How a simple and powerful pulse power supply is running. Inverter power supply or startup for auto inverter power supplies with their own hands

The scope of application of pulsed power supplies in everyday life is constantly expanding. Such sources are used to power all the modern household and computer equipment, to implement uninterruptible power supply sources, batteries for batteries for various purposes, the implementation of low-voltage lighting systems and for other needs.

In some cases, the purchase of a ready-made power supply is little acceptable from an economic or technical point of view and assembling a pulsed source with their own hands is the optimal output from such a situation. It simplifies such an option and the wide availability of a modern element base at low prices.

The most popular in everyday life is impulse sources with power supply from the standard AC network and a powerful low-voltage output. Structural scheme This source is shown in the figure.

The network rectifier SV converts the variable voltage of the supply network into constant and smoothing the ripples of the straightened voltage at the output. The high-frequency converter of the RFP transforms the straightened voltage into an alternating or unipolar, having a form of rectangular pulses of the required amplitude.

In the future, such a voltage or directly, or after straightening (HV) enters a smoothing filter, the load is connected to the output. The RFP control is carried out by the control system receiving the feedback signal from the load rectifier.

Such a structure of the device may be criticized due to the presence of multiple conversion links, which reduces the source efficiency. However, with the right choice of semiconductor elements and the qualitative calculation and manufacture of motion units, the level of power loss in the diagram is small, which allows to obtain the real efficiency of the efficiency above 90%.

Circuits of pulsed power supplies

Decisions of structural blocks include not only the rationale for the choice of scheme implementation options, but also practical recommendations for the choice of the main elements.

To straighten the network single-phase voltage, one of three classic schemes depicted in the figure are used:

• single-alterogeneous;
• zero (two-speech-mode with an average point);
• dVXPOLUPERIOUS MOST.

Each of them is inherent in dignity and disadvantages that determine the scope.

Single-Perside scheme It has simplicity of sales and minimum semiconductor components. The main disabilities of such a rectifier are a significant amount of pulsation of the output voltage (there is only one half-wave of the network voltage in the straightened) and a small rectification coefficient.

Rectification coefficient Kv.determined by the ratio of the average voltage value at the output of the rectifier UDKvalid value of phase network voltage UF.

For single-alterogeneic scheme KV \u003d 0.45.

For smoothing pulsation at the output of such a rectifier, powerful filters are required.

Zero, or two-speech diagram with medium dotAlthough it requires a doubled number of rectifying diodes, however, this deficiency is largely compensated by a lower level of ripples of the straightened voltage and the increase in the magnitude of the rectification coefficient to 0.9.

The main disadvantage of such a scheme for use in domestic conditions is the need to organize an average network voltage point, which implies the presence of a network transformer. Its dimensions and mass are incompatible with the idea of \u200b\u200ba small-sized homemade impulse source.

Two-footer-line bridge scheme Straightening has the same indicators for the level of pulsation and the rectification ratio, which is zero scheme, but does not require network availability. This compensates for the main disadvantage - a double number of rectifier diodes both from the point of view of the efficiency and cost.

For smoothing pulsations of straightened voltage the best solution is the use of a capacitive filter. Its use allows you to raise the magnitude of the straightened voltage to the amplitude value of the network (at UF \u003d 220V UFM \u003d 314B). The disadvantages of such a filter it is customary to consider the large values \u200b\u200bof impulse currents of rectifying elements, but this deficiency is not critical.

The selection of the rectifier diodes is carried out by the magnitude of the average direct current Ia and the maximum reverse voltage U Bm.

Taking the value of the pulsation coefficient of the output voltage of KP \u003d 10%, we obtain the average value of the rectified voltage UD \u003d 300B. Taking into account the capacity of the load and efficiency of the RF converter (80% is accepted for the calculation, but in practice it turns out above, it will allow some reserve).

Ia - the average current of the rectifier diode, the power of the load, η - the efficiency of the RF converter.

The maximum reverse voltage of the rectifier element does not exceed the amplitude value of the network voltage (314B), which allows the use of components with a value U BM \u003d 400B with a significant reserve. You can use both discrete diodes and ready-made rectifier bridges from various manufacturers.

To ensure a given (10%) pulsation at the output of the rectifier, the capacitance of the filter capacitor is taken at the rate of 1MKF to 1W output power. Electrolytic capacitors are used with a maximum voltage of at least 350V. Capacities of filters for different power are shown in the table.

High-frequency converter: its functions and schemes

The high-frequency converter is a single or two-stroke key converter (inverter) with a pulse transformer. Options for RF transducers are shown in the figure.

Single scheme. With the minimum number of power elements and simplicity of implementation, has several flaws.

1. The transformer in the scheme works on the private hysteresis loop, which requires an increase in its size and overall power;
2. To provide power at the output, it is necessary to obtain a significant amplitude of the pulse current flowing through the semiconductor key.

The scheme has found the greatest use in low-power devices, where the effect of these disadvantages is not so significant.

To independently change or install a new meter, no special skills are required. The choice of correct will ensure correct accounting of the current consumption and will increase the safety of the home power grid.

IN modern conditions Ensuring lighting both indoors and streets are increasingly using motion sensors. This attaches not only comfort and convenience to our dwellings, but also allows you to save substantially. Discover practical advice By selecting the installation site, the connection schemes can be.

Two-stroke scheme with an average transformer point (Pushpule). Received its second name from the English version (Push-Pull) description of the work. The scheme is free from the disadvantages of the one-bit option, but has its own - the complicated transformer design (the manufacture of identical sections of the primary winding is required) and increased requirements for the maximum voltage of keys. Otherwise, the decision deserves attention and is widely used in pulse sources Nutrition made by their own hands and not only.

Two-stroke welded scheme. According to the parameters, the diagram is similar to the diagram with the midpoint, but does not require a complex configuration of the transformer winding. The own disadvantage of the scheme is the need to organize the middle point of the rectifier filter, which entails a fourfold increase in the number of capacitors.

Due to the simplicity of implementation, the scheme is most widely used in pulse power sources with a capacity of up to 3 kW. At high capacity, the cost of the filter capacitors becomes unacceptable high compared to the semiconductor keys of the inverter and the bridge scheme is most advantageous.

Two-stroke pavement scheme. By parameters, similar to other two-stroke schemes, but is devoid of the need to create artificial "midpoints". A double number of strength keys becomes a pay for this, which is beneficial with economic and technical points of view to build powerful pulsed sources.

The selection of the keys of the inverter is carried out according to the amplitude of the collector current (drain) I CMA and the maximum voltage collector-emitter uham. For calculation, load power and the transformation coefficient of the pulse transformer are used.

However, before you need to calculate the transformer itself. The pulse transformer is performed on the ferrite core, permalloe or twisted in the ring of transformer iron. For power up to units of kW, ferrite cores of ring or W-shaped type are fully suitable. The transformer calculation is based on the required power and frequency of the conversion. To eliminate the appearance of acoustic noise, the conversion frequency is desirable to be taken out of the sound range (made above 20 kHz).

In this case, it must be remembered that with frequencies close to 100 kHz, losses in ferrite magnetic pipelines significantly increase. The transformer calculation itself is not difficult and can easily be found in the literature. Some results for various sources and magnetic pipelines are shown in the table below.

The calculation is manufactured for a frequency of conversion of 50 kHz. It is worth noting that when working at a high frequency, the effect of turning out the current to the surface of the conductor takes place, which leads to a decrease in the efficient winding area. To prevent this kind of trouble and reduce losses in conductors, it is necessary to carry out a multiple cross section. At a frequency of 50 kHz, the permissible diameter of the winding wire does not exceed 0.85 mm.

Knowing the load capacity and transformation coefficient can be calculated in the primary winding of the transformer and the maximum stream of the power key collector. The voltage on the transistor in the closed state is selected higher than the straightened voltage entering the input of the RF transducer with some reserve (U camaes\u003e \u003d 400V). According to these data, the keys are selected. Currently, the best option is the use of IGBT or MOSFET power transistors.

For the rectifier diodes on the secondary side, it is necessary to observe one rule - their maximum operating frequency must exceed the frequency of the conversion. Otherwise, the efficiency of the output rectifier and the converter will generally decrease significantly.

Video about the manufacture of the simplest pulse feeder

A little about the use and uPS device

The site has already published an article in which it is described about the UPS device. This topic can be somewhat added with a small stories about the repair. Under the Abbreviation, the UPS is often mentioned. So that there were no discrepancies, we agree that this article is a pulse power supply.

Almost all pulsed power supplies used in electronic hardware are built on two functional schemes.

Fig.1. Functional schemes of pulse power supplies

According to the half-spin diagram, it is usually quite powerful powerful power supplies, such as computer. The two-stroke scheme also produces powerful power supplies and welding machines.

Who was the repair of 400 amplifiers and more watts, knows what their weight is perfect. We are talkingNaturally, the prick with traditional transformer block Nutrition. UPS televisions, monitors, DVD players are most often made according to a scheme with a single output cascade.

Although other varieties of output cascades are actually existed, which are shown in Figure 2.

Fig.2. Output Castes of Pulse Power Supplies

Here are only power keys and primary winding power transformer.

If you carefully look at Figure 1, it is not difficult to notice that the entire scheme can be divided into two parts - primary and secondary. The primary part contains a network filter, network voltage rectifier, power keys and power transformer. This part is galvanically connected to the AC network.

In addition to the power transformer, in pulsed power blocks, still unleashing transformers are used through which the PWM controller controllers are fed to the valves (bases) of power transistors. In this way, a galvanic isolation from the secondary chain network is provided. In more modern schemes, this junction is carried out using optocouples.

The secondary chains are galvanically tied from the network using a power transformer: the voltage from the secondary windings is fed to the rectifier, and then in the load. The secondary chains also feed stabilization and protection schemes.

Very simple pulse power supplies

Performed on the basis of the autogenerator when the controller asks the PWM. As an example, such a UPS can be brought to the Taschibra electronic transformer.

Fig.3. Electronic transformer Taschibra.

Similar electronic transformers are issued by other firms. Their main purpose is. A distinctive feature of a similar scheme is simplicity and a small number of details. The disadvantage can be considered that this scheme is simply not started, the output voltage is unstable and has a high level of ripples. But the light bulbs are shine! At the same time, the secondary chain is completely untied from the supply network.

It is clear that the repair of such a power supply is reduced to replacing transistors, resistors R4, R5, sometimes VDS1 and R1 resistor performing the role of the fuse. It's just nothing more in this scheme to burn. With a small price of electronic transformers, a new one is often bought, and the repair is made, which is called, "from love for art."

First, the safety technique

Since soon there is such a very unpleasant neighborhood of the primary and secondary chains, which in the process of repair must, albeit even by chance, will have to feel with their hands, then some safety regulations should be reminded.

You can touch the source included only with one hand, in no case are not at once. This is known to everyone who works with electrical installations. But it is better not to touch at all, or, only after disconnecting from the network by pulling the plug from the outlet. Also, you should not solder something to solder or simply turn the screwdriver.

In order to provide electrical safety on the charges of the power blocks "Dangerous", the primary side of the board will be burned with a large enough strip or shaded with thin paint strips, more often than white. This is a warning that this part of the board is dangerous.

Even the pulsed power supply unit can be rolled by hand only after a while, not less than 2 ... 3 minutes after shutdown: on high-voltage capacitors, the charge is saved sufficiently long, although there are discharge resistors in any normal power supply unit parallel to capacitors. Remember how a charged condenser was offered to each other! To kill, of course, will not kill, but the blow is quite sensitive.

But the worst thing is not even in this: Well, think, slightly tweaked. If immediately after turning off the electrolytic condenser with a multimeter, then it is quite possible to go to the store for a new one.

When such a measurement is foreseen, the condenser must be discharged, at least tweezers. But it is better to do this with a resistor resistance to several dozen com. Otherwise, the discharge is accompanied by a bunch of sparks and quite loud-clicking, and it is not very useful for a capacitor.

And yet, during repair, it is necessary to concern the included pulsed power supply, at least for carrying out some measurements. In this case, the reassembling transformer will help to maximizely protect the transformer, often called the security transformer. How to make it, you can read in the article.

If, in a nutshell, this is a transformer with two windings by 220V, with a capacity of 100 ... 200W (depends on the power of the repaired UPS), the electrical circuit is shown in Figure 4.

Fig.4. Security transformer

The left over the winding circuit is included in the network, a faulty power supply unit is connected to the right winding through the light bulb. The most important thing is that such an inclusion is that one hand can be touched by one hand to any end of the secondary winding, it is possible to uselessly, as well as all the element of the primary power supply circuit.

On the role of light bulbs and its power

Most often, the repair of the pulsed power supply unit is performed without a disconnecting transformer, but as an additional security measure, the inclusion of the block is made through the light bulb with a capacity of 60 ... 150W. On the behavior of the bulb, you can, in general, judge the state of the power supply. Of course, such an inclusion will not provide a galvanic junction from the network, it is not recommended to touch your hands, but it may well protect from smoke and explosions.

If, when you turn on the network, the light lights up in full swing, then a malfunction in the primary chain should be signed. As a rule, it is a pierced power transistor or rectifier bridge. With the normal operation of the power supply, the bulb first flashes quite brightly (), and then the thread of the heat continues to shone weakly.

There are several opinions about this light bulb. Someone says that it does not help to get rid of unforeseen situations, and someone believes that the risk of spilling just the walled transistor is much reduced. We will stick to this point of view, and the light bulb to repair.

About collapsible and unintended corps

Most often, pulsed power supplies are performed in the housings. It is enough to remember the computer power supplies, various adapters included in the outlet, laptop charger, mobile phones, etc.

In the case of computer power supplies, everything is simple enough. Of metal housing Several cogs are turned off, the metal cover is removed and, please, the entire board with the details are already in hand.

If the case is plastic, then you should search on the back of the back, where there is a network fork, small coarseers. Then everything is simple and understandable, turned away and removed the lid. In this case, we can say that it's just lucky.

BUT B. lately Everything goes along the way to simplify and reduce the cost of structures, and the halves of the plastic case are simply glued, and quite firmly. One comrade was told how he drove into some kind of workshop such a block. To the question, how to disassemble the masters said: "You, not Russian?". After that, they took the hammer and quickly split the body into two halves.

In fact, this is the only way to disassemble plastic glued enclosures. But it is necessary to bother neatly and not very fanatically: the paths leading to massive parts can be blocked by the body by the body, for example, transformers or throtters.

It also helps the knife inserted in the seam, and a slight tapping on it is all the same hammer. True, after the assembly, traces of this intervention remain. But let there be minor traces on the building, but you do not have to buy a new block.

How to find a schema

If in former times, in almost all domestic production devices, fundamental electrical circuits were attached, then modern foreign electronics producers share their secrets do not want. All electronic equipment is completed only by the user manual, where it is shown, which you need to press the buttons. Circuit diagrams to user guidelines are not attached.

It is assumed that the device will work forever or repairs will be made in authorized service centers, where there are repair manuals referred to as Service Manual. Service centres Do not have the right to share with all those who wanted this documentation, but, praise the Internet, for many devices, these service manuals can be found. Sometimes it may turn out free, that is, for nothing, and sometimes the necessary information can be obtained for a minor amount.

But even if the desired scheme could not be found, it is not worth a despair, especially when repairing power supplies. Almost everything becomes clear with attentive consideration of the board. This powerful transistor is nothing more than the output key, but this microcircuit is the PWM controller.

In some controllers, a powerful output transistor "hidden" inside the chip. If these parts are fairly dimensional, then they have complete marking, which can be found technical documentation (Data Sheet) chip, transistor, diode or stabilion. It is these parts that make up the basis of pulsed power supplies.

It is somewhat more difficult to find datasheets on small SMD components. Full marking on a small case is not placed, instead of it, a code designation of several (three, four) letters and numbers is installed on the housing. On this code using tables or special programsFreeding again on the Internet, it is possible, the truth is not always, to find the reference details of the unknown element.

Measuring instruments and tools

To repair pulsed power supplies, you will need the tool that each radio amateur has. First of all, it is a few screwdrivers, glass-booths, tweezers, sometimes passage and even mentioned above the hammer. This is for fitting and installation work.

For soldering works, of course, you will need a soldering iron, it is better somewhat, various power and dimensions. It is quite suitable for a regular soldering iron with a capacity of 25 ... 40W, but it is better if it is a modern soldering iron with a thermostat and a temperature stabilization.

To disappear multiple parts, it is good to have at hand if not super thorough, then at least a simple inexpensive soldering hair dryer. This will allow without special efforts and the destruction of printed circuit boards to have multiple details.

To measure voltages, resistance and several less frequent currents, you will need a digital multimeter, even if not very expensive, or the good good shooter tester. That emergency device It is too early to write off the bills that it gives additional features that modern digital multimeters can be read in the article.

Invaluable help in repairing pulsed power supplies can be provided. It is also quite possible to use an old, not even a very broadband electron beam oscilloscope. Unless of course there is an opportunity to purchase a modern digital oscilloscope, then it is even better. But, as practice shows, when repairing pulsed power supplies, you can do without an oscilloscope.

Actually, during repair, two outgoings are possible: either to repair or make even worse. It is appropriate to recall the Horner's law: "The experience is growing directly in proportion to the number of disabled equipment." And although this law contains a pretty share of humor, in the practice of repairing things in this way. Especially at the beginning of the way.

troubleshooting

Pulse power supplies fail much more often than other nodes of electronic equipment. First of all, it affects that there is a high network voltage, which, after straightening and filtering, becomes even higher. Therefore, the power keys and the entire invertor cascade work in very serious mode, both electrical and heat. Most often, the fault lies in the primary chain.

Faults can be divided into two types. In the first case, the failure of the pulse power supply is accompanied by smoke, explosions, destruction and charging parts, sometimes tracks pCB.

It would seem that the simplest option is enough just to change the burnt details, restore the tracks, and everything will work. But when trying to determine the type of chip or transistor, it turns out that, together with the case, the part markings and marking the part. What was happening here, without a scheme, which is more often at hand, it is impossible to know. Sometimes repairs at this stage ends.

The second type of malfunction is quiet, as Lyoul said, without noise and dust. The output voltage was just lost without a trace. If this pulse power supply is a simple network adapter It seems to be a charger for a cell or laptop, then first of all it is necessary to check the health of the output cord.

Most often a break occurs either around the output connector, or at the exit of the case. If the unit is included in the network using a cord with a fork, then first should be verified in its serviceability.

After checking these simple chains, you can already climb into the debris. As these Debreys, take a diagram of the 19-inch monitor of the LG_FLATRON_L1919S. Actually, the fault was quite simple: yesterday turned on, and today it does not turn on.

With the apparent severity of the device - as-no, the monitor, the power supply circuit is quite simple and visual.

After opening the monitor, several swollen electrolytic capacitors were detected (C202, C206, C207) at the output of the power supply. In this case, it is better to change all the capacitors at once, only six pieces. The cost of these parts is kopecking, so you should not wait for it, too, will also be aback. After such a replacement, the monitor earned. By the way, such a malfunction in LG monitors is quite frequent.

The expanded capacitors caused the operation of the protection scheme, the operation of which will be told a little later. If, after replacing capacitors, the power supply has not earned, you will have to look for other reasons. To do this, consider the scheme in more detail.

Figure 5. Monitor power supply LG_FLATRON_L1919S (to enlarge click on the drawing)

Network filter and rectifier

Network voltage through the SC101 input connector, F101 fuse, the LF101 filter enters the BD101 rectifier bridge. The straightened voltage through the TH101 thermistor enters the smoothing capacitor C101. On this condenser turns out constant pressure 310V, which enters the inverter.

If this voltage is missing or much less than the specified value, then you should check the F101 network fuse, the LF101 filter, the BD101 rectifier bridge, C101 condenser, and the TH101 thermistor. All of the specified details are easy to check with a multimeter. If there is a suspicion of the C101 capacitor, then it is better to change it to knowingly well.

By the way, the network fuse just does not burn. In most cases, its replacement does not lead to the restoration of the normal operation of the pulse power supply. Therefore, you should look for other reasons leading to the burning of the fuse.

The fuse should be placed on the same current that is specified in the diagram, and in no case is not "to power" the fuse. This can lead to even more serious faults.

Inverter

The inverter is made according to the one-stroke scheme. As a specifying generator, the U101 PWM controller chip is used to the output of which the power transistor Q101 is connected. To the flow of this transistor through the FB101 throttle, the primary winding of the transformer T101 is connected (conclusions 3-5).

Additional winding 1-2 with rectifier R111, D102, C103 is used to power the PWM of the U101 controller in the steady operation of the power supply operation. Run the PWM controller when turned on is made by the R108 resistor.

Output voltages

The power supply generates two voltages: 12V / 2A to power the backlight lamp inverter and 5V / 2A to power the logical part of the monitor.

From the winding of 10-7 transformer T101 through the diode assembly D202 and the filter C204, L202, C205 is obtained 5V / 2A voltage.

The winding 8-6 is connected to the winding 10-7, from which the D201 and filter C203, L201, C202, C206, L201, C202, C203, C207 obtains a constant voltage of 12V / 2A.

Protection against overload

The source of the transistor Q101 includes a R109 resistor. This is a current sensor that via the R104 resistor is connected to the output 2 of the U101 chip.

When the output overload through the transistor Q101 increases, which leads to a voltage drop on the R109 resistor, which via the R104 resistor is fed to output 2cs / FB chips U101 and the controller ceases to produce control pulses (6out output). Therefore, the voltages at the output of the power supply disappear.

It is this protection that has been triggered when expanded electrolytic capacitors, which mentioned above.

The response level of the protection of 0.9V. This level is given by the source of the sample voltage inside the chip. Parallel to the resistor R109 is connected to ZD101 stabilization voltage with a stabilization of 3.3V, which ensures the protection of the input 2cs / fb from high voltage.

To the conclusion 2cs / fb via the divider R117, R118, R107, a voltage of 310V is supplied from the C101 capacitor, which ensures the operation of protection against increased network voltage. A permissible range of network voltage, in which the monitor is normally working in the range of 90 ... 240V.

Stabilization of output voltages

Made on adjustable stabilion U201 type A431. The output voltage is 12V / 2A via a divider R204, R206 (both resistor with a tolerance of 1%) is fed to the U201 R Stabitron control input. As soon as the output voltage becomes equal to 12V, the stabilion opens and the PC201 op op op op op opens.

As a result, the optology transistor opens, (conclusions 4, 3) and the supply voltage of the controller via the R102 resistor is fed to the output 2cs / fb. The pulses on the terminal 6Out disappear, and the voltage at the outlet 12V / 2A begins to fall.

The voltage on the control input R of Stabilite U201 drops below the reference voltage (2.5V), the stabilion is locked and turns off the PC201 optocoupler. At the output 6Out impulses appear, the voltage 12V / 2A begins to increase and the stabilization cycle is repeated again. Similarly, the stabilization circuit is built in many pulsed power supplies, for example, in computer.

Thus, it turns out that the controller input is 2cs / fb using a wired or immediately three signals: overload protection, protection against network voltage and output voltage stabilizer circuit output.

Here it is relevant to remember how you can check the work of this stabilization loop. For this, just when it is turned off !!! From the power supply unit to submit to the output 12V / 2A voltage from the adjustable power supply.

On the output of PC201 clinging better by the arrow tester In the measurement mode of resistance. While the outlet voltage adjustable source Below 12V, the resistance at the OPBROD output will be large.

Now we will increase the tension. As soon as the voltage becomes more than 12V, the arrow of the appliance will fall aside aside the resistance. This suggests that Stabytron U201 and PC201 optocouplers are good. Consequently, the stabilization of output voltages should work normally.

Alternatively, you can also check the operation of the stabilization loop in computer pulse power supplies. The main thing is to deal with what voltage is the stabilion is connected.

If all of the specified checks have been successfully, and the power supply is not started, then you should check the transistor Q101, dropping it from the board. With a good transistor, the most likely, the chip U101 or its impunity. First of all, this is the electrolytic capacitor C105, which is best to check the replacement to the obviously good.

When a car for a long time It costs without a case, you need to start it at least once a month. The battery is well supplied with electricity a car for 4-5 years, then it is not able to normally provide electricity machine, and also poorly charged from the generator or portable charger. After much experience assembling welding inverters, I have an idea to make a device to start the engine based on such machines.

This device can be used both with a battery installed and without it. FROM rechargeable battery inverter power supply It will even easier to start the engine. I tried to start the engine without a battery for 88 horsepower. The experiment was a success, without any breakdown.

On the inverter you need to adjust the output voltage of 11.2 V. Starter of the internal combustion engine, designed for such a voltage (10-11 V). Inverter block Nutritionwhich we collect has the ability to stabilize the voltage, as well as the function of protection against maximum currents 224 A, protection against electrical wiring.

IGBT technology According to which the electrical circuit of the device was developed, based on the principle of complete opening and the complete closure of powerful transistors, which are used in the block. This makes it possible to better minimize the losses on IGBT keys.

At the output, it is possible to adjust the strength of the current and voltage due to the change in the width of the power keys control pulses. Since they work at high frequencies, then the adjustment must be carried out at a frequency of 56 kHz. Such idealization is possible only with a stable frequency at the output, as well as hold it at such levels under which the power supply is valid. In this case, it will be changed, only the width and duration of the voltage in the range (0% - 45%), from the pulse width. The remaining 55% is the zero level of voltage on the control key.

Inverter block transformer It has a ferrite core. This makes it possible to adjust the device at a high frequency of 56 kHz. Vortex currents are not created on the metallic core.

IGBT transistors - have the necessary power, and also do not create vortex fields around them. Why do you need to create such high frequencies in the power supply? The answer is obvious. When using a transformer, the higher the voltage frequency, the less you need the turns of the winding on the core. Another advantage of a high frequency of work, a high transformer efficiency, which in this case becomes 95%, since the core winding is made of thick wire.

Transformer device Used in the scheme small on the dimensions and very easy. The latitudinal pulse device (PWM) - creates less losses, stabilizing the voltage, compared with the analog elements of stabilization. In the latter case, the power dissipates on powerful transistors.

Those people who disassemble a bit in electronics may notice that the transformer connects to the power source during cycles. One connects to a plus, another to minus. Electrical constructing circuit based on the principle of fli tank provides for connecting a transformer with one key. Such a connection leads to large loss of power (a total of about 10-15% of total power), since inductive windings dispel energy on the resistor. Such power losses are not allowed to build powerful power supplies to several kilowatts.

In the shown scheme This defects eliminated. Energy emissions goes through the VD18 and VD19 diodes back to the power of the bridge, which in turn increases the transformer efficiency even more.

Losses on the additional key become no more than 40 watts. The Flea Tank scheme provides such losses on the resistor that are 300-200 watts. The IRG64PC50W transistor, which is used in the power circuit with IGBT technology, has a quick opening feature. At the same time, the speed of closure is much worse, which produces a crystal to pulsed heating at the time of the transistor closure. On the walls of the transistor, about 1 kW of energy in the form of heat is distinguished. Such power is very large for the transistor, which is fraught with overheating.

To reduce this instantaneous power between the collector and the emitter of the transistor, include an additional C16 R24 VD31 chain. The same thing was done with the upper IGBT transistor, which reduces the power on the crystal at the time of closing. Such implementation leads to an increase in power at the time of opening the transistor key. But it happens almost instantly.

At the time of opening the IGBT, the C16 condenser is discharged through the R24 resistor. Charging occurs at the time of closing the transistor through the fast diode VD3. As a result, the voltage rise format is delayed. While the IGBT is closed - the power released on the transistor key is reduced.

Such a change in the electrical circuit is perfectly coping with transformer resonging emissions, thereby not allowing voltage above 600 volts through the key.

IgBT. - This is a composite transformer, which consists of a field and bipolar transistor with the transition. The field transistor acts here as the main one. In order for them to control the rectangular pulses with an amplitude of at least 12 V, as well as not more than 18 V. On this section of the circuit, special optocoules are included (HCPL3120 or HCPL3180). Possible pulse workload is 2 A.

Optron works in this way. In the event that the voltage on the optro LED appears, the inputs 1,2,3 and 4 are powered. At the output instantly, a powerful current pulse with an amplitude of 15.8 V. The pulse level is limited to resistors R55 and R48.

When the voltage on the LED disappears, the amplitude recession is observed, which opens the T2 and T4 transistor. This creates a current more high level On resistors R48 and R58, as well as a quick discharge of the IGBT key condenser.

The bridge along with the drivers on the optocouplers we collect on the basis of the radiator from the Pentium 4 computer, which has a flat base. On the surface of the radiator, before installing the transistors, you must apply thermal paste.

The radiator needs to be cut into two parts so that the upper and lower key does not have electric contact between themselves. Diodes are attached to the radiator with special mica gaskets. All power connections are installed using the use of mounted mounting. On the power bus, you will need to solder 8 pieces of film capacitors 150 NF each and the maximum voltage of 630 V.

Output winding of the power transformer and choke

Since the output voltages without load reaches 50 V, it must be necessary to straighten with the VD19 and VD20 diodes. The load voltage is then enabled to the throttle with which the stress is smoothed and dividing the voltage in half.

During when IGBT transistors are open, the l3 choke saturation phase occurs. When IGBT is in a closed state, the choke discharge phase occurs. The discharge occurs through the closing chain diode VD22 and VD21. Thus, the current that enters the capacitor straightens.

Stabilization and current limit at latitude emotional modulation

2 is an input for increasing voltage, 1 - output of the amplifier. The amplifier changes the operating current of the inverter, as well as the width of the pulse. Discrete changes create a load characteristic depending on the feedback voltage between the power supply and the input of the microcircuit. The output of 2 chips is maintained voltage 2.5 V.

The width of the working impulse depends on the voltage at the inlet 2 chip. The width of the pulse becomes wider if the voltage is more than 2.5 V. If the voltage is less than the specified one, then the width is coated.

The stability of the power supply is depends on the resistors R2 and R1. If the voltage is strongly seats due to large output currents, it is necessary to increase the resistance of the resistor R1.

Sometimes it happens that in the process setting the block begins to make some buzzing sounds. In this case, it is necessary to adjust the resistor R1 and the capacitance of C1 and C2 capacitors. If even such measures are not able to help, you can try to reduce the amount of turns of the C3 throttle.

The transformer must work quietly, otherwise transistors burn. If even all of the above measures did not help, you need to add several capacitors of 1 μF to three Channels of BP.

Capacitor Board 1320 μF

During the power supply of the power supply into the network with a voltage of 220 V, the current jump occurs, after which fails diode assembly VD8, while charging the capacitor capacity. To prevent such an effect, you need to install the R11 resistor. When the capacitors are charged, the timer on the zero transistor will give the command to sway the contacts and draw the relay. Now the current work current comes to the electric bridge with the transformer.

The timer on VT1 opens the contacts of the relay K2, which allows the use of the process of latitude-filled modulation.

Setting block

First of all, it is necessary to submit a voltage of 15V on the power bridge, trace the correct work of the bridge as well as the installation of elements. Next, you can save the bridge with the voltage of the network, into the gap between +310 V, where 1320 μF capacitors and a condenser with a capacity of 150 NF are located, put a light bulb for 150-200 watts. Then we connect to the electrical chain of the Ospilograph on the emitter collector of the bottom power key. It is necessary to make sure that the emissions are located in the normal zone, not higher than 330 V. Next, set the tact frequency of Shima. It is necessary to reduce the frequency until it appears on an oscillogram of a small bending of the pulse, which indicates the reduction of the transformer.

The working clock frequency of the transformer is calculated in this way: first we measure the clock frequency of the transformer's oversaturation, we divide it to 2 and the result add to the frequency on which the pulse bend occurred.

Then you need to power the bridge over the kettle, 2 kW. We disconnect the PWM voltage feedback, supply the adjustable voltage to the resistor R2 in the connection site with the stabitron D4 from 5 V to 0, thereby adjusting the closure current from 30 A and to 200 A.

Configure a voltage at a minimum, closer to 5 V, we move the capacitor C23, closing the output of the block. If you heard the ringing, you need to skip the wire to the other side. Check the phasing of the power transformer windings. We connect the oscilloscope to the bottom key and increase the load so that there is no stall, or even a voltage burst above 400 V.

We measure the temperature of the bridge radiator so that the radiator is heated evenly, which indicates high-quality bridges. Connect the feedback on the voltage. We put the C23 condenser, measure the voltage so that it is in the range of 11-11.2 V. load the power supply by a small load, 40 watt value.

We configure the quiet operation of the transformer, changing the number of turns of the throttle L3. If it does not help, we increase the echo of the C1 and C2 capacitor, or by placing the PWM board away from the interference of the power transformer.

Preface

I want to prevent the respected readers of this article in advance that this article will not have a completely familiar form and content for readers. I will explain why.

The material provided to your attention is absolutely exclusive. All devices of which will be discussed in my articles are designed, macated, configure and bring to mind personally. Most often, everything starts with attempts to implement some interesting idea in practice. The path is very ternist, and sometimes it takes, quite a long time and what will the end result will be, and whether it will be in general - it is not known in advance. But, the practice confirms - the road will be aswaling ..., and the results, sometimes exceed all the expectations ... And as the process itself is fascinating - not to convey words. I should admit that I have known knowledge and skills (like everyone else, it should be noted). Wise and timely tips are only welcome, and help bring the idea to a logical end. Here is the specificity ...

This article is addressed not so much novice, but rather to people already having the necessary knowledge and experience, which is also interested to walk the faded paths, and which the standard approaches to solving tasks are not so interesting ... It is important to understand that this is not a material for thoughtless repetition, but rather - The direction in which you need to move ... I do not promise readers of large details about obvious, well-known and understandable things in electronics ..., but I promise that the main essence will always be well lit.

About the inverter

Inverter, which will be discussed, appeared on the light that described above ... Unfortunately, I can not, not disturbing the rules of publishing these articles, to highlight in detail how it was born, but I assure that the schemes of the two extreme inverter options have not yet Published ... Moreover, the penultimate option of the scheme is already practically used, and the extreme (hopefully - the most perfect one), so far only on paper and has not yet been labeling, but I do not doubt it in performance, and the manufacture and test will take it a couple of days ...

IR2153 acquaintance for the IR2153 semi-bridge inverter, it produced a good impression - a rather small power consumption current, the presence of a did-half, built-in control of the power ... But she has two essential drawbacks - there is no possibility to adjust the pulse duration at the output and a rather small drivers of the drivers ... (Really, it is not voiced in the datashee, but it is unlikely more than 250-500 mA ...). It was necessary to solve two tasks - to come up with how to implement the inverter voltage adjustment, and how to increase the current drivers of power keys ...

These tasks managed to be administered to the optical drivers of field transistors, and differentiating circuits at the IR2153 chip outputs (see Fig. 1)

Fig.1

A couple of words about how the adjustment of the pulse duration is working. The pulses from the IR2153 outputs come to the differentiating chains consisting of elements C2, R2, the optical driver LED, the VD3-R4-transistor of the optical ..., and the elements C3, R3, the optical driver LED, the VD4-R5-R5 transistor of the optical ... The elements of differentiating circuits are calculated in such a way. As closed with a protransstore of feedback, the pulse duration at the outputs of optical drivers is almost equal to the pulse duration at the outputs of IR2153. At the same time, the voltage at the outlet of the inverter is the maximum.

At the moment when the voltage at the output of the inverter reaches the stabilization stabilization, the proton transistor is started, it leads to a decrease in the time constant of the differentiating chain, and, as a result, to reduce the pulse duration at the output of the optical drivers. This ensures the stabilization of the voltage at the output of the inverter. VD1, VD2 diodes eliminate negative emissions arising from differentiation.

The type of optical drivers is deliberately not voicing. That is why - the optical driver of the field transistor, this is a large separate topic for conversation. The nomenclature of them is very large - dozens ... if not hundreds of types ..., for every taste and color. To understand their appointment and their features, it is necessary to study them independently.

The presented inverter has another important feature. I will explain. Since the main purpose of the inverter is charging lithium (although it can be any, of course) batteries, had to take measures to limit the current at the output of the inverter. The fact is that if you connect a discharged battery to the power unit, charging current may exceed all reasonable limits ... To limit charging current on the level you need, in the TL431 control electrode circuit, the RS shunt is entered ... How does it work? The minus of the charged battery is connected not to the minus of the inverter, but to the top according to the conclusion scheme RSh ... when current flow through RS, the potential on the control electrode TL431 ..., which leads to a decrease in the voltage at the output of the inverter, and, as a result, to limit the charging current. As the battery is charging, the voltage on it grows, but after him, the voltage at the outlet of the inverter is growing, striving for stabilization stabilization tension. It is simple, and more effective to the disgrace. By changing the RS rating, it is easy to limit the charge current at any level we need. That is why, the Nominal RS himself is not voiced ... (landmark - 0.1 Ohms and below ...), it is easier to choose experimentally.

Anticipating the set of comments about "correctness" and "incorrectness" of the principles of charging lithium batteries, a big request - from such comments to refrain and believe the word that I am more than aware of how it is done ... This is a large, separate topic ... and within This article will not be discussed.

A few words about the important features of the inverter signaling part ...

To check the performance and configuration of the inverter signal part, you must submit +15 volts into the power supply circuit of the signal part from any external power supply and control the oscilloscope the presence of pulses on the shutters of power keys. Then, it is necessary to simulate the response of feedback (feeding the voltage to the optocoupler) and make sure that it occurs almost a complete narrowing of pulses on the shutters of power keys. At the same time, it is more convenient to connect the probability of the oscilloscope, but otherwise the signal wire of the probe to one of the shutters of the power key, and the overall wire of the oscilloscope is to the shutter of another power key ... This will give the opportunity to see the pulses of different seats at the same time ... (what in the neighboring semi-accomplishes We will see the pulses of the opposite polarity, here does not have a value). Now the most important thing - it is necessary to make sure (or achieve) so that when the feedback is turned on, the control pulses are not tested to zero (the minimum duration remained, but did not lose the rectangular shape ...). In addition, it is important that the resistor R5 (or R4) is to ensure that the pulses in the adjacent separates were the same duration ... (the difference is quite likely, due to the difference characteristics of optical drivers). See Fig.2

Fig.2

After these hassle, the connection of the inverter to the 220 volt network, will pass, most likely without problems. It is very desirable to connect a small load when setting up to the output of the inverter ... due to the nonzero minimum duration of control pulses, without load, the voltage at the inverter output may be higher than the stabilization voltage. It does not interfere with the operation of the inverter, but, from this unpleasant moment, I hope to get rid of the next version of the inverter.

Important about drawing of a printed circuit board - it has a number of features ...

For the past few years I use fees developed under ala-planar installation of elements ... That is, all elements are located on the side of printed conductors. Thus, all the elements of the scheme are soldered ..., even those that are not intended for the planar edge. This significantly reduces the complexity of manufacturing. In addition, the board has an absolutely flat bottom and the ability to place a board directly on the radiator. Such a design simply simplifies the process of replacing items when setting up and repairing. Some connections (the most uncomfortable, for wiring in princess) Perform an isolated mounting wire. This is quite justified, as it can significantly reduce the size of the board.

PCB drawing itself (see cris.3), it is likely the basis for exactly your design. Therefore, the final drawing will need to adjust the optical drivers under your you use. It should be borne in mind that different optical drivers have different enclosures, and the numbering and assignment of the conclusions may differ from the scheme in this article. The presented fee has already experienced decisions of ten modifications regarding the signal part. The adjustment of the signal part, sometimes very significant, takes at all a long time.

Fig. 3.

I do not plan to bring an accurate list of items within this article. The reason is simple - the main goal of all this is useful thing With minimal labor costs from the most accessible elements. That is - collect, from what is. By the way - if the output voltage of the inverter is not planned to do more than twenty volts, you can use any transformer as the output transformer computer Blok. Nutrition (assembled on the semi-bridge circuit). The photo below is a general view of the collected inverter so that you have an idea, as it looks like (better - to see one time than to hear a hundred times). I am very pleased to be condescending to the quality of the assembly, but I just have no way out - the hands are only two ... soldered the current option, and in my head the next option is almost ripe ... and otherwise - no way ...- Through the step you will not jump .. .

Yes, that's what I forgot to mention - I'll certainly have questions about the power of the inverter. I will answer this way - the maximum power of such an inverter is difficult to estimate ..., it is determined mainly by the power of the used power elements, the output transformer and the maximum peak current of the output of optical drivers. For large capacities big influence The design itself, damping chains of power keys will begin to provide ..., It will take the use of synchronous rectifiers instead of diodes at the outlet ... In short, it is already a completely different story, much more complicated in the implementation ... With regard to the described inverter, I use it to charge the LifePO4 battery with voltage 21, 9 volts (capacity - 15a / h) current 7-8 amp ... This is the limit where the temperature of the radiator and the transformer is in reasonable limits and no compulsory cooling is required ... for my taste - cheap and angry ..

I do not plan to talk about this inverter in more detail in this article. It is not possible to light everything (and takes such a cloud of time, it is necessary to notice ...), so it will be more reasonable to discuss the questions that have arisen in a separate topic on the soldering iron forum. There I will listen to all the wishes and critical comments, and I will answer questions.

I have no doubt - very many may not like this approach. And many are confident that everything is already invented before us ... I assure it is not the case ...

But this is not the end of the story. If there is an interest, then it will be possible to continue the conversation ... because there is one more, the extreme version of the signal part. ... I hope - the continuation should be.

Additions from 06/25/2014

This is how it turns out this time - I have not managed to dry ink in the article, and there were already very interesting thoughts, how to make the signal part of the inverter more perfect ...

I want to warn that all drawings marked with the signature "Project" in a fully assembled inverter were not checked! But if, the performance of individual fragments of the scheme was tested on the layout, and their performance was confirmed, I will be prompted.

The principle of operation of the modified signal part is still based on the differentiation of pulses from the IR2153 chip. But from the point of view of the correctness of the construction of electronic circuits, the approach here is more competent.

A pair of explanations - actually differentiating chains now include C2, R2, R4 and C3, R3, R5 plus VD1, VD2 diodes, and feedback opamp. Diodes that eliminate negative emissions arising from differentiation are excluded ..., since they do not need to be needed - field transistors allow the supply of the valve of the shutter +/- 20 volts. The indinged pulses that change their duration when exposed to the feedback is applied to the T1, T2 transistor shutters, which include Optical Driver LEDs ...

This scheme is checked on the layout. It showed good performance and greater flexibility in the setup. I strongly recommend to use.

In the photo below, the fragment of the concept with a modified signal part and the picture is printed with corrections for the modified signal part ...

To be continued...

Update on 06/29/14

This is how the extreme version of the inverter signaling, which I mentioned at the beginning of the article looks like. Finally, I found time to make his layout and see in the realities of his work ... I looked ... and that - yes, it is he who will be appointed the most perfect of the proposed ... The scheme can be called successful and because all the elements in it perform functions for which And designed from birth.

In this variant of the regulator, a different, more familiar, method for changing the duration of the managers. The pulses from the outputs of IR2153 are converted from rectangular, in a triangular form, integrating circuits R2, C2 and R3, C3. The generated triangular impulses come to the inverting inputs of the Dual LM393 comparator. The non-screwing inputs of comparators comes with voltage from the R4, R5 divider. Comparators compare the current value of the triangular voltage with the voltage from the R4, R5 divider, and at the moments when the value of the triangular voltage exceeds the voltage from the R4, R5 divider, low potential occurs on the outputs of the comparators. This leads to the inclusion of the Optical Driver LED ... An increase in the voltage from the divider R4, R5 leads to a decrease in the pulse duration at the outputs of the comparators. That is how to organize the feedback of the output of the inverter with the duration of the pulse duration, and to ensure, thereby stabilization and control of the output voltage of the inverter. When a feedback optron is triggered, the optical transistor is open, the voltage from the divider R4, R5 increases, which leads to a decrease in the duration of control pulses ..., wherein the output voltage is reduced ... The size of the resistor R6 * determines the degree of influence of the feedback chain on the duration of the formed pulses ... - than the value of the R6 * resistor * less, the less the duration of the pulses when the feedback is triggered ... when setting up, the change in the ratio of the R6 resistor *, makes it possible to ensure that the duration of the formed pulses at the time of operation of the feedback will strive (or will be equal - here It is not scary) to zero. Figures below will help to understand the essence of the work of comparators.

A pair of words about important when setting up. The setup procedure itself is quite simple, but to make it without an oscilloscope - do not even try ... it is equivalent to attempts to drive with blindfolded eyes ... Feature (and this, rather, his dignity than the flaw) is that it will make it possible to form impulses With any ratio of durations in neighboring channels ... It is necessary to understand that the formitor can how to change (enter or eliminate completely) the duration of the did-time between the impulses of adjacent channels, but even form them so that the impulses of adjacent channels will "overlap" on each other ... that, naturally, it is unacceptable ... Your task - controlling the oscillating pulses at the output of the drivers, changing the value of the resistor R4 *, to put such a voltage on non-converting inputs of comparators, in which pulses separated by did-timer will be formed on the outputs of the drivers 1 -2 μs (than did-time wider - the risk of through currents is less).

Then, it is necessary to turn on the feedback opamp, and, changing the size of the resistor R6 *, select it in such a time at which the duration of the formed decreases to zero. During this procedure, it will not be harmful to control the moment of disappearance of the formable pulses. It is very desirable that the complete disappearance of the impulses formed occurred at the same time ... an unlimited disappearance is possible if the parameters of integrators R2, C2 and R3, C3 are strongly different. This can be cured with a small change in the denominations of the elements of one of the integrators. I did it practically. For convenience, temporarily, instead of the circuit, the transistor Optron-R6 *, connected the potentiometer to 20 kΩ, and set the pulse duration on the edge of the disappearance. The difference in the duration of the formed pulses, turned out to be insignificant ... But I also eliminated it, settling the addition capacitor (only 30 PF), parallel to the C3 condenser.

A pair of words about the features of optical drivers ... When configured, it turned out that the optical drivers work better with a larger current of LEDs. I use, there is one more important nuance - the Optro LED consumes a larger current not for the entire duration of the pulse, but only in sufficiently short periods (1-23), coinciding over time with the positions of the fronts of pulses. This is important, since it makes it possible that the average current consumed by the Optodrava LED is really not at all high. These considerations are due to the choice of the R7 resistor rating. The actually measured peak current of the oprodear LED, with the value indicated in the diagram, is 8-10 mA.

The diader (VD5) is added to the circuit in the circuit in the power chain of the bottom driver. I will explain why. Applied by me by the optodrayer, have a built-in power control system. Due to the fact that a diode is always used in the power supply chain of the top driver, the voltage of the upper driver always turns out to be slightly lower than the supply voltage of the lower drivers. Therefore, when a supply voltage is reduced, pulses from the output of the top driver disappear a little earlier than the lower. To bring closer to turning off the drivers and the diode VD5 is introduced. You should always pay close attention to these moments ...

Here, it's time to notice that this formator can be used (after a small change in the logic of the comparator) together with the usual (not optical) drivers of semi-bridges. Who did not understand what we are talking, see, for example, what is IR2113. Like darkness ... and their use may be even more preferable than optical ... But this is the topic for the next addition to the article ... I do not promise that I will check their work in practice, but at least at the level schemes several options - no problem ....

This is how many beats - but really the setting is reduced to the selection of two resistors. I want to note that this formator is not critical of its nutrition - in the IR2153 chip power range (9-15 volts), it works absolutely adequately. The disappearance of the pulses from the IR2153 outputs with a decrease in its power (at the time of turning off the block), leads to the closure of power keys.

A more couple of tips - do not try to replace IR2153 with a certain analogue on discrete elements - it is not productive ... Really, it is possible, but it's just not reasonable - the number of details will grow at times (in the original - there are only three of them ... where less). In addition, you will have to solve questions on the behavior of the analogue when you turn on and off (and they will be unambiguous). The fight against this will further complicate the scheme, and the meaning of this venture will be reduced to no ...

For those who, this topic is interesting, I attach for a convenience adjusted for this formator drawings of printed circuit boards. Among them is the actual formator in the form of submodule ... - It is more convenient to start the first acquaintance with them. Especially emphasized - if you decide to try to configure the driver autonomously (without connecting the power keys), remember that when configured, you must connect the "virtual" total top driver, with a real common wire (otherwise - the top driver will be missing).

Although I did not plan further change in the inverter, but it should be noted that the presence of only one chain of the duration adjustment will easily enter any current protection in it. This is a separate interesting topic, and we may return to her later ...

In conclusion of this supplement, I remind - from birth, the main purpose of the inverter is charging lithium batteries. Special, very important properties, it is emphasized in the RS scheme ... who did not realize his appointment, I recommend to delve into the section of the article in which it is about it.

If you do not use RS (move) - we will have a conventional inverter with voltage stabilization (but, without any protection, naturally ...).

List of radio elements

Designation	A type	Nominal	number	Note	Score	My notebook
	Power Driver and Mosfet	IR2153.	1			In notebook
	IC source of reference voltage	TL431	1			In notebook
T1, T2.	Field-effect transistor		2			In notebook
VD1-VD6.	Diode		6			In notebook
VD7, VD8.	Rectifying diode	FR607.	2			In notebook
VD9.	Diode bridge	RS405L	1			In notebook
	Optopara		1			In notebook
	Optical driver		2			In notebook
C1	Capacitor	3900 PF	1			In notebook
C2, C3, C10	Capacitor	0.01 μF.	3			In notebook
C4.		100 μF 25 in	1			In notebook
C5, C6.	Capacitor	1 μF.	2			In notebook
C7, C12	Capacitor	1000 PF	2			In notebook
C8, C9.	Electrolytic condenser	150 μF 250 V	2			In notebook
C11.	Electrolytic condenser	1000 IFF	1			In notebook
R1	Resistor	5.1 com	1			In notebook
R2, R3	Resistor	1.3 com	2			In notebook
R4, R5	Resistor	110 Oh.	2			In notebook
R6, R7	Resistor	10 Oh.	2			In notebook
R8, R9	Resistor	10 com	2			In notebook
R10, R15	Resistor	3.9 com	2	R10 0.5 W.		In notebook
R11	Resistor	3 com	1	0.5 W.		In notebook
R12.	Resistor	51 Oh.	1	1 W.		In notebook
R13, R14.	Resistor	100 com	2			In notebook
R16, R18	Resistor	1 com	2			In notebook
R17	Resistor	7.76 com	1			In notebook
RS	Resistor	0.1 Ohm and less	1			In notebook
	Transformer		1	From computer bp		In notebook
	Inductor		1			In notebook
F1.	Fuse	2 A.	1			In notebook
	Specifying generator. Option number 2.
	Power Driver and Mosfet	IR2153.	1			In notebook
T1, T2.	Mosfet transistor	2N7002.	2			In notebook
	Optopara		1			In notebook
	Optical driver		2			In notebook
VD1-VD3.	Diode		3			In notebook
C1	Capacitor	2200 PF	1

The welding inverter from the computer unit is becoming increasingly popular both among professionals and amateur welder. The advantages of such devices are that they are comfortable and lungs.

The use of an inverter power source allows you to qualitatively improve the characteristics of the welding arc, reduce the size of the power transformer and thereby facilitate the weight of the device, makes it possible to make more smooth adjustments and reduce splashing during welding. The disadvantage of an inverter type welding machine is a significant price than that of the transformer counterpart.

In order not to overpay in stores large amounts of money for welding, you can make. This requires a working computer power supply unit, several electrical measuring instruments, tools, basic knowledge and practical skills in electrical work. Also it will not be useful to acquire appropriate literature.

If there is no confidence in your abilities, it is necessary to apply for the finished welding machine to the store, otherwise, with the slightest error in the process of assembly, there is a risk of obtaining electrodes or burn all the wiring. But if you have experience to collect schemes, rewind transformers and create electrical appliances with your own hands, you can safely begin the assembly.

The principle of operation of inverter welding

The welding inverter consists of a lower voltage voltage of a power transformer, choke-stabilizers that reduce the pulsation of the current, and the power supply unit. For circuits, you can apply MOSFET or IGBT transistors.

The principle of the inverter is as follows: alternating current from the network is sent to the rectifier, after which the power module conversion occurs direct current Variable with increasing frequency. Further, the current comes to a high-frequency transformer, and at the outlet of it turns out the current of the welding arc.

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Tools required for the manufacture of the inverter

To collect welding inverter From the power supply with your own hands, the following tools will be needed:

• soldering iron;
• screwdrivers with different tips;
• pliers;
• nippers;
• drill or screwdriver;
• crocodiles;
• wires of the desired section;
• tester;
• multimeter;
• consumables (wires, solder for soldering, tape, screws and others).

To create a welding machine from a computer power supply, materials are needed to create a printed circuit board, getinax, spare items. To reduce the amount of work, it is worth contacting the store for finished holders for electrodes. However, they can be made and independently, soldering the crocodiles to the wires of the required diameter. With this work, it is important to observe polarity.

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Order of the assembly of the welding machine

First of all, to create a welding machine from a computer power supply, you need to get the power supply from the computer housing and make it disassembly. The main elements that can be used from it is a few spare parts, a fan and standard housing plates. It is important to take into account the cooling mode. It depends on which items to provide the necessary ventilation should be added.

The work of the standard fan, which will cool the future welding machine from the computer unit, must be tested in several modes. Such an inspection will make sure to work the element. In order for the welding machine during the work, it is possible to put an additional, more powerful cooling source.

To control the required temperature, install the thermocouple. The optimal temperature for the operation of the welding machine should not exceed 72-75 ° C.

But first of all, you should install on the welding machine from the computer unit of the required size handle for carrying and convenience. The handle is installed on the top panel of the block with screws.

It is important to choose screws optimal in length, otherwise too large can hurt the inner scheme, which is unacceptable. At this stage of work should be worried about the good ventilation of the device. The placement of the elements inside the power supply unit is very dense, therefore it should be in advance to arrange a large number of through holes. They are performed by a drill or screwdriver.

Next, to create a circuit inverter, you can use several transformers. Typically choose 3 transformers such as ETD59, E20 and KX20X10X5. You can find them in almost any radio electronics store. And if there is already experience in creating transformers yourself, it is easier to perform them with your own hands, focusing on the number of turns and the performance of transformers. Find similar information on the Internet will not be any difficulty. You may need a current transformer K17x6x5.

Perform homemade transformers is best of all from getanakse coils, the winding will serve the enamel wire, cross section 1.5 or 2 mm. You can use a copper tin 0.3x40 mm, having previously wrapped it with durable paper. The thermobumage is suitable from the cash register (0.05 mm), it is solid and is not so torn. The crimp should be made of wooden pads, after which the entire design should be pouring "epoxy" or to cover with varnish.

By creating a welding machine from a computer unit, you can use a microwave transformer or old monitors, without forgetting to change the number of turns of the winding. With this work, it will be useful to use electrical literature.

You can use PIV as a radiator, pre-painted on 3 parts, or other radiators from old computers. You can buy them in specialized stores involved in disassembling and upgrading computers. Such options will allow pleasantly saving time and strength in search of suitable cooling.

To create a device from a computer power supply unit, you must use a one-dimensional Speat Quasimistic Bridge, or "Spit Bridge". This element is one of the main in the work of the welding machine, so it is better not to save on it, but to purchase a new one in the store.

Printing boards can be downloaded on the Internet. This will greatly facilitate the recreation of the scheme. In the process of creating the board, you will need condensers, 12-14 pieces, 0.15 MK, 630 volts. They are needed to block the resonant current emissions from the transformer. Also, to make such a machine from a computer unit, you will need C15 or C16 capacitors with a K78-2 or SWV-81 brand. Transistors and output diodes should be installed on radiators without using additional gaskets.

During operation, it is necessary to constantly use the tester and multimeter to avoid errors and for a faster assembly of the circuit.

After the manufacture of all the necessary parts, it is necessary to place them in the case followed by their wiring. The temperature on the thermocouple is worth setting 70 ° C: it will protect the entire design from overheating. After assembly, the welding machine from the computer block must be preset. Otherwise, with an error allowed during assembly, you can burn all the basic elements, and then get the blow to the current.

On the front side, you should install two contact holders and several current strength regulators. The device switch in such a design will be the standard computer unit toggle switch. The case of the finished apparatus after the assembly is required to additionally strengthen.