SU1264272A1 - Device for controlling d.c.converter with a.c.element - Google Patents

Abstract

The invention relates to electrical equipment and can be used to control converters. The aim of the invention is to increase reliability. The capacitor 27 of the integrator 14 is charged in the vertical portion of the hysteresis loop of transformer 1. The end point of this path is determined by the gain of the amplifier 21. As the magnetising current decreases almost to a normal value, the voltage of the amplifier 21 decreases and the frequency of the master oscillator 18 is set close to the initial value. If each subsequent half-wave of the magnetization current differs from the previous one, this leads to a proportional change in the frequency of the master oscillator in such a way as to shift the partial cycle of the remagnetization (Lag to the side of the magnetisation current.) Additional distortion of the output voltage is eliminated and the magnetization current is stabilized. 2 silt

Description

The invention relates to electrical engineering and can be applied in the control of high-speed voltage regulators, key amplifiers operating in devices with an intermediate link at a higher frequency. The purpose of the invention is to increase reliability. FIG. 1 shows a functional diagram of an adjustable voltage converter and devices for controlling it; in fig. 2 - diagrams on the operation of the device. The device contains harmonics transformer 1, the primary and secondary windings of which are included in the high-frequency inverter 2 diagonals performed on fully controlled switches 3-6, and the demodulator 7, also executed on the keys 8 11, the low frequency diagonal of the inverter 2 is connected to the input the converter terminals via the consumed current sensor 12, and the demodulator diagonal - in series with the load Z, the magnetization current meter 13, connected to the primary and secondary circuits of the matching transformer, the integrator 14, A pulse puller 15, phase shifter, blocks 16 and 17, a frequency-controlled master oscillator 18, the paraphase output of which is intended to be connected to the control circuits of keys 8-11 of the demodulator, and the other output connected to one of the input blocks 16 and 17, other inputs are combined to form the control input 19 of the device, and the paraphase outputs are intended for connection to the control circuits of the keys 3 and 4, 5 and 6, the inverter, the reference voltage source 20, the error signal amplifier 21, the storage unit 22, half-wave top mute 23, full-wave a single rectifier 24, two equal keys 25 and 26, a switch 25 are humbled by the integrator capacitor 27 of the integrator 14, and the switch 26 is switched on by the output of the integrator 14 and the output of the unit 22. The meter 13 is completed in the form of two current transformers 28 and 29, primary the windings of which are connected in series with the primary and secondary windings of transformer 1, and the secondary windings are interconnected between themselves with each other and form a meter output. FIG. 2 denotes the signal 30 at the paraphase outputs of the generator 18; control voltage 31 acting on control input 19; sawtooth support voltages 32 and 33 of blocks 16 and 17. The device operates as follows. If a constant supply voltage is applied to the converter input, and when signals 30, 34 and 35 are applied (Fig. 2) to the control of the key chain 3-6 and 8-11, the phase angle of the control signals 34 and 35 and, therefore, the algorithm the closures of the keys of the inverter 2 are determined by the voltage 31. At a minimum value of voltage 31 in the interval from zero to time t, signals 34 and 35 are in antiphase, and the phases of signals 30 and 34 coincide. The positive half waves of signals 34 and 35 correspond to the on state of the switches 3 and 5 of inverter 2, and the negative ones to the switched on states of the keys 4 and 6. The positive half waves of the voltage 30 correspond. (the on state of the keys 8 and 11 is turned on, and the negative state is on the state of keys 9 and 10 of demodulator 7. A change in the voltage level 31 leads to a change in the phase shift between the signals 34 and 35. In Fig. 2, the input voltage 31 is set by stepwise variation Thus, it is possible to trace all possible modes of operation of the power circuit: 1) the mode of summing up the voltage of the demodulator with the voltage of the power source (0 t ti); 2) overvoltage control mode (t t t); 3) undistorted transmission mode (tj t tj); 4) the voltage control mode of the demodulator of the voltage deducted from the voltage Uo (tj: t t); 5) mode (t t ,,). The first mode is provided at a value of voltage 31 applied to the combined input 19 (Fig. 1) of phase shifting blocks 16 and 17, less than the minimum value of voltages 32 and 33. Signals 34 and 35 are generated at the outputs of blocks 16 and 17. Key closure algorithm Inverter 2 of demodulator 7 is completely determined by the phases of signals 30, 34 and 35. In the demodulator, the keys are switched in pairs, and the positive half of the waveform of 30 corresponds to the closed coil of keys 8 and 11, and the negative to the closed state of keys -9 10. In the time interval About tt, in the first half IRS simultaneously closed in the inverter keys 3 and 6. The primary winding of the transformer 1 is connected to the positive beginning and source. In the demodulator, the keys 8 and 11 are simultaneously closed, and the load current flows through the circuit :, plus Ug - the end of the secondary winding of transformer 1 (at which a negative potential operates) - the beginning of this winding - key 11 - load 2 minus Uo. The voltage source U and the winding of the transformer 1 are turned on according to, the load has a voltage 36 equal to the sum of these voltages. In the second half-period, the keys 3 and 6 of the inverter are open, the keys 5 and 4 are closed — the primary winding of transformer 1 is connected to the positive side Uo by the end, voltage 37 changes polarity, in demodulator the keys 9 and 10 are closed, the load current runs through the circuit : plus U - key 10 is the beginning of the secondary winding of transformer 1 (at which a negative potential acts) - the end of this winding - key 9 - load Z - min UQ. And in this half period, the voltage 36 remains constant. Further, the processes are repeated. As the voltage increases, 31 (t t t) changes from the phase of the signals 34 and 35, with the phase behind the signal 34 changing in the direction of lagging, and the phase of voltage 35 leading to the leading direction. This will lead to a change in the inverter key switching algorithm. At t t ,, the voltage addition and and additional mode is maintained, then the key 6 opens and the key 5 closes when the key 3 is closed - the transformer 1 is short-circuited and its voltage on the windings becomes zero, and the voltage i UQ is applied to the load. In this mode, keys 8 and 11 of the demo port are turned off and keys 9 and 10 are turned on without breaking the circuit to draw load current. Then the key 3 opens, closes the key 4, which corresponds to the negative half-voltage of the transformer windings and the summation of this voltage Uo. Next, the processes are repeated, alternating the additive mode with undistorted transmission. Increasing the control voltage 31 to half the amplitude of the voltages 32 and 33 (t t tj) drives. It leads to the undistorted transmission mode, since the phases of signals 34 and 35 are equal and coincide with the transformer 1 being shorted all the time. A further increase in voltage 31 is accompanied by a reversal of the polarity of the voltage on the transformer windings with respect to the original first mode, while maintaining which voltage 36 would change as shown in FIG. 2 dotted line. Key locking algorithm in this mode: 4i5-5iZ-Zi6-6i4. In particular, at tt, the keys 4 and 5 are simultaneously closed and the power supply end is connected to the end of the primary winding of transformer 1, which corresponds to the negative polarity of voltage 37. The load current flows through the circuit: plus U - key 8 - end of the winding of transformer 1 (in which the positive potential acts) the end of this winding - key 11 - load .ZP - minus and, since the demodulator key switching algorithm is preserved. A voltage difference U and the output voltage of the demodulator 7 is applied to the load. At tt, the phases of the signals 34 and 35 change by t (the total shift is 2F), while the inverter keys 4 and 5 are simultaneously closed in one half period and keys 3 and 6, which corresponds to the maximum voltage on the windings of the transformer and counter-switching it on with the voltage of the power source and ,. The operation of the inverter and demodulator keys is determined by the operation of the control device. Suppose that transformer 1 operates in a symmetrical mode with this induction and the magnetizing current is determined by the magnitude and form of voltage 37. The current consumed by the inverter (in idle mode) is determined by the magnetizing current, but when switching keys, the reactive component scattering inductance of the transformer 1. The frequency of the master oscillator 18 and the rate of change of the sawtooth voltage is determined by the magnitude of the output voltage amplified 21, which is equal to the difference of the reference voltage across the source voltage The voltage sensor 20 and the output voltage of the unit 22. The voltage of the unit 22 is formed as follows. The output voltage of the meter 13, proportional to the magnetizing current 1 ,. Vtp ml of the full-wave expander 24 and is fed to the input of the integrator 14. The magnitude of the output voltage of the integrator at the time of the change of the sign of the voltage 30 is equal to the average value Ij for the inverter half-voltage. At the end of each half-period, a signal from one of the outputs of its generator 18 is outputted by the generator 15 and a pulse is received to the control; the input of the key 26, the closure of which leads to a rewriting of the voltage level of the block 22, which remains constant until the next driver 15. At the same time, from the output voltage of the sensor 12, the rectifier 23 separates the negative and current currents of the inverter, coming to the input of the driver 15, at the second output of which pulses are generated. Thus, after the key 26 is unlocked, the key 1 is key 25 and the higher voltage of the integrator 14 becomes zero. In this case, the charge of the capacitor 27 starts with zero initial conditions. In the symmetric mode of operation of the transformer 1, the half-wave current is equal, therefore, the voltage at the integrator's output does not differ in magnitude from half-period to half-period. For this reason, the output voltage of the unit 22 and the output voltage Life Amplifier 21 does not change. A change in voltage 31 at time t leads to a change in the phase shift of signals 34 and 35 between themselves and with respect to voltage 30. A change in the operating mode leads to an increase in the magnetizing current. The voltage at the output of the integrator increases in proportion to the increase in IP, but at the output of block 22, a voltage proportional to the average value IM for the previous half-period still acts, therefore the frequency of the master oscillator is unchanged. When the key 26 is pinched, the voltage at the output of the block 22 increases in a jump. The error signal at the output of amplifier 4 decreases, losing the frequency of the master oscillator 18 and the rate of change of sawtooth voltages 32 and 33. The impulse of the driver .15 closes key 25, which opens when the magnetizing current (the negative current consumed by the inverter becomes zero. Thus, the capacitor 27 of the integrator 14 begins to charge almost in the vertical portion of the hysteresis loop of the transformer 1. The end point of this trajectory is determined by the gain of the amplifier 21 and can be chosen any one on the vertical section of the hysteresis loop. Since the magnetization current decreases to almost normal (symmetrical) value, the voltage of the amplifier 21 decreases again at a time, and the frequency of the master oscillator 18 is set to the initially specified value. the half-wave of the magnetized w} (its average value) differs from the previous one in one direction or another, it often changes proportionally of the master oscillator in the direction of decreasing it, thus To move the partial magnetization reversal in the direction of reducing cycle magnetizing current. As a result, additional distortions of the output voltage are eliminated and the magnetizing current is stabilized, which leads to an increase in the reliability of the converter. An increase in the load current can lead to a change in the magnitude and duration of the reactive component of the inverter current, and, consequently, to an insignificant change in the frequency of the master oscillator in the direction of its increase. Thus, the use of the device eliminates the jiocTopoHHero mode of the transformer at the expense of stabilizing the magnetizing current and improves the reliability of the converter, and the stabilization is carried out without forcing the control pulses to change, which guarantees the exclusion of additional distortions and reduction in the mass and size of filter devices. converter

71

formula of invention

A device for controlling a DC converter with an AC link consisting of an inverter, a transformer and a demodulator containing an integrator, a pulse shaper, two phase-shifting units, the outputs of which are intended to be connected to the inverter of the converter, and a controlled drive generator, the first outputs of which They are intended for connection to the converter demodulator, the second output is connected to the first inputs of phase-shifting units, the second inputs of which are connected to the control input CTBA, characterized in that, in order to increase reliability, it is provided with a source of reference voltage, vychitayu1TsIM amplifier, a current transformer magnetization meter, a storage unit odnopoluperiodnm

642728

and a full-wavelength detector and two controllable keys, the first controllable key is connected between the integrator's input and output, the integrator's 5th output is connected via a second controlled key and a storage unit to the first input of the detracting amplifier, the second input of which is connected to the output source of the reference 0 the voltage of the subtractive amplifier is connected to the third inputs of the phase-shifting units and the input of the controlled master oscillator, the first of which is output through the driver

5 pulses are connected to the control input of the second control key, the control input of the first control key is connected via a pulse shaper and a one-wavelength rectifier to the output of the inverter current sensor, and the output of the transformer magnetizing current meter is connected to the integrator via the full-wave rectifier.

Claims (1)

Claim A device for controlling a DC-DC converter with an AC link consisting of an inverter, a transformer and a demodulator, comprising an integrator, a pulse shaper, two phase-shifting units, the outputs of which are intended to be connected to the inverter of the converter, and a controlled master oscillator, the first outputs of which are intended to be connected to the converter demodulator, the second output is connected to the first inputs of the 15 phase-shifting units, the second inputs of which are connected to the control input of the device Twa, characterized in that ', in order to increase reliability, it is provided with a source of 0 ₂ nick reference voltage subtracter amplifier, meter transformer magnetizing current, a storage unit, a half-wave and full-wave rectifiers and two controlled switches, · wherein the first controllable switch is connected between the input and output of the integrator, the output of the integrator is connected through a second controlled key and a storage unit to the first input of the subtracting amplifier, the second input of which is connected to the output of the reference voltage source voltage, the output of the subtracting amplifier is connected to the third inputs of the phase-shifting units and the input of the controlled master oscillator, the first outputs of which are connected through the pulse shaper to the control input of the second controlled key, the control input of the first controlled key is connected through the pulse shaper and a half-wave rectifier with the output of the inverter current sensor, and The output of the transformer magnetization current meter is connected through a half-wave rectifier to the integrator input. figure 2