Transformers of impulse sources. Space technology. TPI type transformers What power pulse TPI 4

Screwdriver, or rechargeable drill is a very convenient tool, but there is a significant disadvantage - when active use The battery discharges very quickly - in a few dozen minutes, and hours are required for charging. Do not even save the presence of a spare battery. A good exit from the position when conducting work in a room with a 220V operating power grid would be external source To power the screwdriver from the network, which could be used instead of battery. But, unfortunately, industrial sources are not available, specialized sources for powering screwdrivers from the mains (only charging device For batteries that cannot be used as a network source due to insufficient output current, but only as a charger).

In the literature and the Internet there are proposals as a power source for a nominal voltage 13V to use car chargers based on a power transformer, as well as power supplies from personal computers And for halogen lighting lamps. All this is possible good options, but not claiming originality, I propose to make a special power supply yourself. Moreover, on the basis of a diagram, a different destination power supply can be made.

And so, the source scheme is shown in the picture in the text of the article.

This is a classic reverse AC-DC converter based on PWM generator UC3842.

The voltage from the network enters the bridge on VD1-VD4 diodes. On the C1 condenser stands out constant pressure About 300V. This voltage is powered by a pulse generator with a T1 transformer at the output. Initially, the starting voltage enters the power output 7 IC A1 through the R1 resistor. The microcircuit pulses generator turns on and issues pulses at the output 6. They are fed to a powerful shutter field Transistor VT1 in the stock circuit of which the primary winding of the pulse transformer T1 is included. The operation of the transformer begins and the secondary voltages appear on the secondary windings. Voltage from winding 7-11 straightens the VD6 diode and used
to power the A1 chip, which turns on the permanent generation mode begins to consume a current that is not capable of maintaining a start-up power source on the R1 resistor. Therefore, when the Diode malfunction VD6, the source pulsates, - through R1 C4 capacitor is charged to the voltage required to start the microcircuit generator, and when the generator starts the increased C4 current discharge, and the generation stops. Then the process is repeated. With the health of the VD6, the diagram immediately after starting it turns into power from the winding of the 11 -7 transformer T1.

The secondary voltage is 14V (at idle 15v, under full load 11V) is taken from the winding 14-18. Straightens the VD7 diode and smoothes the C7 capacitor.
Unlike a typical scheme, a circuit of the output key transistor VT1 from high current stock source is not used. And the protection of the anti-exit 3 chip is simply connected to the total minus power. Cause this solution In the absence of the author in the presence of a necessary low-level resistor (still have to do from what is in stock). So the transistor here is not protected from current overload, which is certainly not very good. However, the scheme has been working for a long time without this protection. However, if desired, you can easily make protection, following a typical scheme for inclusion of the UC3842 IC3842.

Details. The pulsed transformer T1 is ready by the TPHI-8-1 from the power module of the MP-403 color domestic TV type 3-USLD or 4-USL. These TVs now often go to the disassembly either are thrown away. And TPI-8-1 transformers are available on sale. The diagram of the number of the conclusions of the transformer windings is shown according to the labeling on it and on the concept of the MP-403 power module.

The TPI-8-1 transformer has other secondary windings, so that you can get another 14V using the winding 16-20 (or 28V is connected sequentially 16-20 and 14-18), 18V with winding 12-8, 29V with winding 12- 10 and 125V with winding 12-6. This way you can get a power source to feed any electronic device, for example, UNH with a preliminary cascade.

But this is limited to this, because rewinding the TPI-8-1 transformer, is a rather ungrateful job. His core is tightly glued and when trying to share it breaks at all where you expect. So in general, any voltage from this block will not get out, except with the help of a secondary downstream stabilizer.

The IRF840 transistor can be replaced by IRFBC40 (which is also the same in principle), or on BUZ90, KP707V2.

The KD202 diode can be replaced with any more modern straightening diode on a direct current not lower than 10a.

The radiator of the key transistor can be used as a radiator for the transistor VT1, a radiator of a key transistor, a little converting it.

Fig. 1. Scheme of the network filter board.

In Soviet TVs, the Horizon C-257 was used a pulsed power source with an intermediate conversion of a network voltage of 50 Hz to the rectangular pulses with a rectification frequency of 20 ... 30 kHz and their subsequent straightening. The output voltages are stabilized by changing the duration and frequency of repetition of pulses.

The source is made in the form of two functionally finished nodes: the power module and the power filter board. The module is secured by the television chassis from the network, and the elements are galvanically associated with the network, closed with screens that restrict access to them.

The main specifications of the pulse power supply unit

• Maximum output power, T.........100
• Efficiency..........0,8
• Limits of network voltage changes, in......... 176...242
• Unstable output voltages,%, no more..........1
• Nominal values \u200b\u200bof current loads, Ma, voltage sources, in:
  135 ....................500
  28 ....................340
  15 ..........700
  12 ..........600
• Mass, kg .................. 1

Fig. 2. Schematic scheme Power module.

It contains a network voltage rectifier (VD4-VD7), a start-up cascade (VT3), stabilization nodes (VT1) and 4VT2 locks), a converter (VT4, VS1, T1), four single-alipeside output voltage rectifiers (VD12-VD15) and a voltage compensation stabilizer 12 V (VT5-VT7).

When the TV is turned on, the network voltage through the restrictive resistor and the interference circuit, located on the power filter board, enters the VD4-VD7 rectifier bridge. The voltage straightened by them through the magnetization winding of the I pulse transformer T1 passes to the VT4 transistor collector. The presence of this voltage on C16 condensers, C19, C20 indicates the HL1 LED.

Positive power voltage pulses through capacitors C10, C11 and R11 resistor charge C7 Cascade Cascade Conductor. As soon as the voltage between the emitter and the base 1 of the single-pass transistor VT3 reaches 3 V, it opens and the C7 capacitor is quickly discharged through its emitter transition - base 1, emitter transition of the VT4 transistor and resistors R14, R16. As a result, the VT4 transistor opens by 10 ... 14 μs. During this time, the current in the magnetization winding of I increases to 3 ... 4 A, and then when the VT4 transistor is closed, decreases. The pulse voltages arising on windings II and V are straightened by diodes VD2, VD8, VD9, VD11 and Capacitors C2, C6, C14 are charged: the first one is charged from winding II, two others - from the winding of V. with each subsequent turning on and off of the transistor VT4 is recharging capacitors.

As for the secondary chains, at the initial moment after turning on the TV, the C27-SZO capacitors are discharged, and the power module works in mode close to the short circuit. At the same time, all the energy accumulated in the T1 transformer enters the secondary chains, and the auto-oscillating process in the module is absent.

Upon completion of charging capacitors oscillation of residual energy magnetic field In the T1 transformer create such a voltage positive feedback In the winding V, which leads to the emergence of an auto-oscillating process.

In this mode, the VT4 transistor opens with a voltage of positive feedback, and is closed with a voltage on the C14 condenser entering the vs1 thyristor. It happens so. A linearly growing current of the current transistor VT4 creates a voltage drop on the resistors R14 and R16, which in positive polarity through the R10C3 cell arrives at the Tristor VS1 control electrode. At the time determined by the trigger threshold, the thyristor opens, the voltage on the C14 condenser is applied in reverse polarity to the emitter transition of the VT4 transistor, and it closes.

Thus, the inclusion of a thyristor specifies the duration of the saw-shaped pulse of the collector current of the transistor VT4 and, accordingly, the amount of energy given to the secondary chains.

When the output voltages of the module reaches nominal values, the C2 capacitor charges so much so that the voltage removed from the R1R2R3 divider becomes more voltage on the VD1 stabilion and the transistor VT1 of the stabilization node opens. Some of its collector current is summarized in the circuit of the thyristor control electrode with a current of the initial displacement generated by the voltage on the C6 condenser, and the current arising from the voltage on the resistors R14 and R16. As a result, the thyristor opens earlier and the collector current of the transistor VT4 decreases to 2 ... 2.5 A.

With an increase in the voltage of the network or reduce the load current, the voltage increases on all the windings of the transformer, and consequently, the voltage on the C2 condenser. This leads to an increase in the collector current of the transistor VT1, the earlier opening of the vs1 thyristor and the closure of the VT4 transistor, and therefore, to reduce the power given to the load. Conversely, with a reduction in network voltage or increasing the load current, the power transmitted to the load increases. Thus, all output voltages are stabilized. The trim resistor R2 establishes their initial values.

When short circuit One of the outputs of the module auto-oscillations are broken. As a result, the VT4 transistor is opened only by a trigger cascade on the VT3 transistor and is closed by a vs1 thyristor when the current reserves of the transistor VT4 value is 3.5 ... 4 A. The pulse packets appear on the power frequency and the fill frequency of about 1 kHz on the transformer windings. In this mode, the module can work for a long time, since the collector current of the VT4 transistor is limited to a permissible value of 4 A, and the currents in the output circuits are safe values.

In order to prevent large current shots through the VT4 transistor with an excessively low voltage of the network (140 ... 160 V) and, therefore, with an unstable triggering of a thyristor VS1, a blocking node is provided, which in this case turns off the module. The proportional to the rectified network constant voltage from the R18R4 divider, and the Emitter, comes to the VT2 transistor pulse voltage The frequency of 50 Hz and amplitude determined by the VD3 stabilitron. Their ratio is chosen such that with the specified voltage of the network, the VT2 transistor opens and the collector current pulses opens a thyristor VS1. The auto-oscillating process stops. With an increase in the voltage of the network, the transistor closes and does not affect the operation of the converter. To reduce the output voltage instability of 12V, a voltage compensation stabilizer on transistors (VT5-VT7) with continuous adjustment is applied. His feature is a current limitation with a short closure in the load.

In order to reduce the effect on other chains of the channel output cascade sound accompaniment It feeds on separate winding III.

IN the pulsed transformer TPI-3 (T1) applies M3000NMS M3000НС x12x20x15 With an air gap of 1.3 mm on the middle rod.

Fig. 3. The layout of the winding of the pulse transformer TPI-3.

The winding data of the TPI-3 transformer of the pulse power supply is given:

All windings are made with PEWTL wire 0.45. In order to uniformly distributing the magnetic field along the secondary winding of the pulse transformer and increasing the communication factor, the winding I is divided into two parts located in the first and last layers and connected in series. Stabilization winding II is performed in a step of 1.1 mm in one layer. Winding III and Section 1 - 11 (I), 12-18 (IV) are wound in two wires. To reduce the level of emitted interference, four electrostatic screens have been introduced between windings and a short-circuit screen over the magnetotrium.

On the power filter board (Fig. 1), elements of a barrier filter L1C1-SZ, a current-limiting resistor R1 and a device for automatic demagnetization of a kinescope mask on the thermistor R2 with a positive TKS, are placed. The latter provides the maximum amplitude of the modulus current to 6 A with a smooth decline for 2 ... 3 s.

Attention!!! When working with a power module and a TV, you must remember that the elements of the power filter board and part of the module parts are under the voltage of the network. Therefore, it is possible to repair and check the power supply module and the voltage filter fees only when it is turned on through a separation transformer.

Pulse power transformers (TPI) are used in pulsed household and office equipment power supply devices with an intermediate supply of power supply 127 or 220 V with a frequency of 50 Hz into a rectangular pulse with a rectangle pulse up to 30 kHz, made in the form of modules or power supplies: BP, MP-1, MP-2, MP-Z, MP-403, etc. Modules have the same scheme and differ only with the type of pulsed transformer used and the denomination of one of the capacitors at the filter output, which is determined by the characteristics of the model in which they are applied.
Powerful TPI transformers for pulse sources Nutrition are used for interchange and energy transmission into secondary chains. Energy accumulation in these transformers is undesirable. When designing such transformers, as a first step, it is necessary to determine the scope of the oscillations of the magnetic induction of DV in the steady mode. The transformer must be designed to work with a greater number of DV, which allows you to have a smaller number of turns in the magnetizing winding, increase the rated power and reduce the induction of the dispersion in practice, the DV value can be limited to either induction of the saturation of the core B S or loss in the transformer magnetic circuit.
In most full-alone, half-lit-off and double-footer (balanced) circuits with a midpoint, the transformer is excited symmetrically. At the same time, the magnetic induction value changes symmetrically with respect to zero characteristics of magnetization, which makes it possible to have theoretical maximum value of DV equal to the double value of the saturation induction of BS. In most single-clock schemes used, for example, in one-stroke transducers, magnetic induction fluctuates completely within the first quadrant of magnetization characteristics from residual induction BR to bs saturation induction limiting the theoretical maximum of two to the value (BS - Br). This means that if the DV is not limited to losses in the magnetic core (usually at frequencies below 50 ... 100 kHz), the transformer of large sizes will be required for one and the same output power.
In the voltage-powered schemes (which include all the schemes of lower stabilizers), in accordance with the Faraday law, the value of DV is determined by the work of the "Volt-second" on the primary winding. In the installed mode, the work of the "Volt-second" on the primary winding is set at a constant level. The swing of oscillations of magnetic induction is thus also constant.
However, with the usual method of controlling the working cycle, which is used by most chips for pulse stabilizers, during start-up and during a sharp increase in the load current, the DV can reach a double value from the value in the steady mode, so that the core is not saturated with the transition processes must be two times less theoretical maximum however, if a chip is used, which allows you to control the value of the "Volt-second" product (schemes with the perturbation of the input voltage), then the maximum value of the "Volt-second" product is fixed at the level, slightly exceeding the established Allows you to increase the value of DV and improves the performance of the transformer.
The value of the saturation induction B s for most ferrites for strong magnetic fields of type 2500NMS exceeds the value of 0.3 T.. In the two-stroke voltage-feed circuits, the magnitude of the increment of induction of DV is usually limited to a value of 0.3 T.. With increasing excitation frequency up to 50 kHz, the magnetic loss loss is approaching the losses in the wires. Increasing the losses in the magnetic core at frequencies above 50 kHz leads to a decrease in the value of DV.
In one-stroke schemes without fixing the work of the "Volt-second" for cores with (BS - Br), equal to 0.2 T., and, taking into account the transient processes, the established value of DV is limited at the level of only 0.1 tl loss in the magnetic circuit at a frequency of 50 kHz will be insignificant due to a small scope of oscillations of magnetic induction. In schemes with a fixed value of the work of the "Volt-second", the DV value can take values \u200b\u200bup to 0.2 T., which makes it possible to significantly reduce the overall dimensions of the pulse transformer.
In the focused current systems of power sources (increasing transducers and drive-driven lowering stabilizers on linked inductors' coils), the value of DV is determined by the work of the "Volt-second" on the secondary winding at a fixed output voltage. Since the work of the "Volt-second" at the output does not depend on changes in the input voltage, the flow of the circuit can work with the VAR value close to the theoretical maximum (if not to take into account the losses in the core), without the need to limit the magnitude of the "Volt-second" .
At frequencies above 50. 100 kHz Value DV is usually limited to losses in the magnetic circuit.
The second step in the design of powerful transformers for pulse power sources must be made right choice A type of core that will not be saturated with a given work of the "Volt-second" and will provide acceptable losses in the magnetic lines and the windings for this can be used the iterative calculation process, however, the formula (3 1) and (3 2) referred to below can calculate the approximate value of the area of \u200b\u200bthe area The core S o S C (the product of the core window S O and the cross-sectional area of \u200b\u200bthe magnetic pipeline S c) of formula (3 1) is used when the Vitive value is limited to saturation, and formula (3.2) - when the DV value is limited to losses in the magnetic circuit in doubtful cases are calculated Both values \u200b\u200band the most of the tables of reference data for different cores are selected that type of core, in which the product S o S C exceeds the calculated value.

where
RVH \u003d rye / l \u003d (output power / efficiency);
To - coefficient, taking into account the degree of use of the core window, the primary winding area and the constructive factor (see Table 3 1); FP - transformer operating frequency


For most ferrites for strong magnetic fields, the hysteresis coefficient is to K \u003d 4 10 5, and the coefficient of losses for vortex currents - KW \u003d 4 10 10.
In formulas (3.1) and (3.2) it is assumed that the windings occupy 40% of the core window area, the ratio between the primary and secondary windings corresponds to the same current density in both windings, equal to 420 A / cm2, and that the total losses in the magnetic circuit breeding and windings They lead to the temperature difference in the heating zone of 30 ° C with natural cooling.
As a third step in the design of powerful transformers for pulse power sources, it is necessary to calculate the winding of the pulse transformer.
In tab. 3.2 The unified power supply transformers of the TPI type used in television receivers are shown.








Winding data of TPI type transformers working in pulse blocks The nutrition of stationary and portable television receivers is shown in Table 3. 3 The fundamental electrical circuits of TPI transformers are shown in Figure 3. 1

[ 28 ]

Designation of transformer	Type of magnetic pipeline		Vilarov windings	Type of winding	Number of Vitkov	Brand and diameter of the wire, mm
		Primary		Private in 2 wires
		Secondary, B. 6,3 26 26 15 15 60	2-1 10-13 6-12 5-12 1-4 3-9	Private Same Private too		0.75 PEVTL-2 0.28 PEVTL-2
		Primary
		Secondary
		Primary
		Secondary
		Primary				PEVTL-2 0 18
		Collector		Private in 2 wires
		Primary		Private in 2 wires		PEVTL-2 0.18
		Secondary
						PEVTL-2 0,315
	Cup M2000 nm-1	Primary
		Secondary
BTS Yostnoy		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary
		Primary
		Secondary

End of Table 3.3.

Designation of transformer	Type of magnetic pipeline	Name of transformer windings	Conclusions of the windings	Type of winding	Number of Vitkov	Brand and diameter of the wire, mm	Resistance dC. Oh.
		Primary	1-13 13-17 17-19	Private in 2 wires
		Secondary		Private center
				Private in 3 wires		PEVTL-2 0 355
		Fourth		Private in 2 wires
				Private in 4 wires
				Private in 4 wires

Winding data of TPI type transformers, operating in pulsed blocks of stationary and portable television receivers, are shown in Table 3 3. Connected electrical schemes of TPI transformers are shown in Figure 3 1

10 IS 15 15 1412 11

Figure 3 1 Electric circuits of TPI-2 type transformers

3.3. Transformers for reverse transducers

As mentioned above, transformers for reverse transducers perform the functions of the electromagnetic energy during the effect of the pulse in the circuit of the switching transistor and, at the same time, the element of galvanic isolation between the inlet and output voltages of the converter so, in the open state of the commuting transistor under the action of switching pulse, the primary magnetizing transformer winding The reverse turn is connected to a source of energy, to the condenser of the filter, and the current in it is linearly increasing at the same time, the polarity of the voltage on the secondary windings of the transformer is such that the rectifying diodes are locked in their chains. Next, when the switching transistor is closed, the voltage polarity on all transformer windings is changed to The opposite and energy, stored in its magnetic field, goes to the output smoothing filters in the secondary windings of the transformer. It is necessary in the manufacture of a transformer to ensure the electromag There would be a maximum possible connection between its secondary windings. In this case, voltage on all windings will have the same shape and instantaneous voltage values \u200b\u200bare proportional to the number of turns of the corresponding winding in this way, the reverse transformer works as a linear throttle, and the accumulation intervals of electromagnetic energy in it and transmission The accumulated energy in the load is separated in time

For the manufacture of reverse transformers, it is best to use armor ferrite magnetic pipelines (with a gap in the central rod), providing linear magnetization

The main procedures for designing transformers for reverse converters consist in choosing a material and shape of the core, determining the peak induction value, determining the sizes of the core, calculating the magnetic gap and the determination of the number of turns and the calculation of the windings, with all the required parameter values \u200b\u200bof the converter scheme elements, such as

the inductance of the primary winding of the transformer, peak and standardized currents and the transformation coefficient must be determined before the calculation procedure.

Selection of material and core shape

The material for the reverse transformer core is most often used ferrite powder molybdenum-permalloe toroidal cores have higher losses, but they are also often used at frequencies below 100 kHz, when the switches of the magnetic flux are small - in the throttle and reverse stroke transformers used in Continuous current mode. Powder iron cores are sometimes used, but they have either too low magnetic permeability value, or too large losses for practical use In pulsed power sources at frequencies of more than 20 kHz.

High values \u200b\u200bof magnetic permeability (3 ooky ... 100 LLC) of the main magnetic materials do not allow to store a lot of energy in them. This property is acceptable for the transformer, but not for the inductor inductor. A large number of The energy that should be stuck in the throttle or transformer of the reverse stroke is actually focused in the air gap, which breaks the path of magnetic power lines inside the core with large magnetic permeability. In molybdenum-permalloe and powder iron cores, the energy accumulates in a non-magnetic binder that holds the magnetic particles together. This distributed clearance cannot be measured or defined directly, instead the equivalent magnetic permeability is given for the entire core, taking into account the non-magnetic material.

Definition of peak induction

The values \u200b\u200bof the inductance and current calculated below relate to the primary winding of the transformer. The only winding of the usual inductor coil (throttle) will also call primary winding. The required value of the inductance L and the peak value of the short-circuit current through the coil of the inductance 1kz is determined by the application scheme. The magnitude of this current is set by the current limitation circuit together both of these values \u200b\u200bdetermine the maximum energy value that the inductance coil should store (in the gap) without saturation of the core and with acceptable losses in the magnetic lines and wires.

Next, it is necessary to determine the maximum peak value of the hydrogen induction, which corresponds to peak current 1x - to minimize the size of the gap required for the accumulation of the required energy, the inductance coil should be used as much as possible in the maximum induction mode. This allows you to minimize the number of turns in windings, losses for vortex currents, as well as the size and cost of inductance coil.

In practice, the value of the BTs is limited to either the saturation of the BS core, or losses in the magnetic circuit. The losses in the ferrite core are proportional to both frequency and the complete scope of the change in the induction of the DV during each switching cycle (switching), erected into a degree of 2.4.

In stabilizers operating in continuous current mode (chokes in low-pass stabilizers and transformers in reciprocating circuits), losses in the core of inductance coil at frequencies below 500 kHz is usually insignificant, since the deviations of magnetic induction from a constant working level are insignificant in these cases, the value of maximum induction can to be almost equal to the value of the saturation induction with a small margin. The value of the saturation induction for most powerful ferrites for strong fields of type 2500H1 \\ / 1C is above 0.3 T., so the maximum induction value can be selected equal to 0.28.p..0.3 T.

I will introduce my own (partially truth borrowed from a more steep special person in this matter, I think it will not be offended) Pyat into this piggy bank.
Before disassembling not harmful to measure the inductance Qoterness of the windings, and even better to remove this data from the live sample to be compared after repair.
In blocking - hair dryer does not always help in the case of large cores. I used to split first with a small laboratory tile, then with a flat ten
An electric kettle (there is even a thermal switch for 150 degrees, but it is possible to include and select the temperature for reinsurance through the LATER). I installed necessarily tightly pressed the free part of the ferrite (if a side of the gluing is pre-tossed by the influx of the adhesive) to the cold surface of the heater and then turned on.
When disassembly, the main patience - pulled the stronger and here the problem is superfluous.
On cores - with disassembly and reverse assembly, there were almost no problems except Grundigs and Panasonic. In the Hurdelov (filled with a compound TPI in old TV), the main problems are just the same with cores more precisely with their configuration. To put another suitable core in size due to the fact that the operating frequency of these TPIs is 3-5 times higher and low-frequency cores do not live in them. In this case, the use of cores from large FBT is saved. For a full recreation, a lively sample is required from the same product to compare the characteristics. (if it is very strained to restore - there is)
(Questions about the cost and feasibility of these works, please do not specify, but the fact remains a fact - such hybrids work.)
With some Panasi, the trick lies in very little gaps and here it helps the preliminary measurement of inductance.
I don't advise to glue the superclaim to T K had several repeats due to cracking of the adhesive seam. A drop of epoxy is certainly vyuly but more reliable, and after gluing it is good to squeeze the joint (for example, feeding constant voltage to the winding - it's still pulling it and it will also be slightly warmed).
About a saucepan with boiling water - I confirm for the case with FBT (it was necessary to exhale the cores of 30 dead flas) works fine, so much on the TPI, which did not have rewind.
On the this moment All that was rewrought (by me, and in particularly severe cases mentioned special N.Novascular) works. There were even successful rewind results. lowercase transformers (with an external multiplier) from enough ancient industrial monitors, but there the secret of success in vacuum impregnation of the windings (by the way Nikolai impresses almost all revealed transresis except the frank broadcast) and on the knee it unfortunately is not treated.
Rematik's device mentioned recently recently trains from dashboard Mercedes - showed everything OK on a deliberately punish trance, however, the Diemenian device also deceived on it - the trance made his way on a rather large voltage that sobs-but allowed him to measure it at low.