SU1418867A1 - D.c. to d.c. voltage control system - Google Patents

Abstract

The invention relates to electrical engineering and can be used to convert a constant voltage into a constant voltage. The purpose of the invention is to reduce the no-load loss of the converter. The device contains an inverter on thyristors 1-4, a rectifier on diodes 9-12, filter capacitors 13, 14, capacitors 15,17,22, 23, reactors 16,18,20,21 and a control unit 24. With a constant pause of pulses load current decreases dependence on load current during recovery of thyristor controllability. As a result, the amplitude of the oscillating circuit current nfn in the absence of saturation of the transformer magnetic circuit is reduced to a value equal to twice the maximum no-load current of the transformer. 2 Il. ate

Description

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The invention relates to electrical engineering and can be used to convert a constant voltage into a constant voltage.

The purpose of the invention is to reduce the no-load losses of the converter. Fig. 1 is a schematic diagram of a device for controlling a DC / DC converter; figure 2 - timing charts of the device.

The device contains an ushverter made according to a bridge circuit on thyristors 1 - A with counter diodes 5-8, rectifier diodes 9-12, capacitors 13 and 14 of the filter at the input of the inverter, capacitor 15 and reactor 16 of the inverter oscillator circuit, capacitor 17 and reactor 18 of the auxiliary circuit, power transformer 19, filter reactors 20 and 21, filter capacitors 22 and 23 at the output of the rectifier, control unit 24, the outputs of which are connected to control 1CIM thyristor transitions 1-4 inverters through current transformers 25-28 and sync input - through the transformer 29 of the current with the output of the master oscillator, made in accordance with the relaxer circuit on the diode thyristor 30 and the capacitors 31 and 32. In order to reduce energy losses and provide a constant pause between load current pulses, the time specifying capacitor 31 is shunted by a discharge circuit made on the transistor 33 according to the current stabilizer circuit and containing resistors 34-36. The base circuit of the transistor 33 is connected to the output of the rectifying bridge 37 via the zener diode 38 and is bridged by a diode 39. At the same time, the input of the bridge 37 is connected to the secondary hydrochloric winding current transformer 40 whose primary is connected in series to the inverter output of the output transformer of the inverter circuit.

To eliminate the possibility of a sharp decrease in the period of the current pulse at the output of the master oscillator when the load disappears, the power supply circuit of the upstream current regulator input is shunted with a pulse key containing the thyristor 41 and diode 42, which are shunted by a series oscillatory circuit including the reactor 43 and the capacitor 44. The thyristor control junction h

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connected to the output of the generator via a current transformer 43, and the potential output of the key is connected to the power source through a resistor 4 (5. Before starting the toggle switch 47, the diode thyristor 30 guards it.

In the initial state, the capacitors 13 and 14 of the filter at the input of the inverter are charged to the voltage of the power supply, and the capacitors 15 and 17 of the switching switching circuits are discharged. The capacitors 31 and 32 of the master oscillator and the capacitor 44 k: 1 are charged to the supply voltage of the control circuit.

At time t, after the contacts of the toggle switch 47 are opened, capacitor 31 begins to discharge.

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u | it gradually decreases by an amount equal to the switching voltage of the diode thyristor 30. When the thyristor 30 is rotated at a time t, a short pulse i flows through the sensor 31 and the primary windings of the current transformers 29 and 45, which ensures the start of the control unit 24, forming a current pulse i, and unlocking the thyristor 41, which shunts the control circuit of the current stabilizer on the transistor 33 and eliminates the discharge of the capacitor 31 in the time interval, the duration of which is equal to the period of natural oscillations of the circuit, containing a reactor 43 and a capacitor 44, due to a decrease in the voltage U- at the anode of the thyristor 41; and the circuit of the control input of the current stabilizer.

The current pulse i provides unlocking of the thyristors 1 and 2 of the inverter. At the same time, current pulses i of the oscillating circuit of the inverter and the load component of the current flow through them (FIG. 3). The impulse of the load component of the current c has a duration shorter than the duration of the period of natural oscillations of the current i of the inverter oscillatory circuit. Due to this, at time tj, when the current pulse through the thyristors 1 and 2 approaches zero, they are locked. However, the current i ,, of the oscillating circuit of the inverter continues to flow through the diodes 5 and 6 of the inverter and the capacitor 14 phi.

During the current prp) flow of current i., Through the primary winding

Matrix 40 of the current at the output of the coupling bridge 37 produces a negative current pulse i, which keeps the current stabilizer on the transistor 33 in the locked state for a time equal to the duration of the load current pulse,

At the moment of time t, at the approach of the load current pulses and the current at the output of the rectifying bridge 37, the current regulator of the discharge of the condenser 31 unlocks to zero. As a result, the capacitor 31 begins to discharge and the voltage on it decreases,

At time tj after the current pulse c decreases to zero, the voltage Uj increases at the input of the inverter, and the voltage Ugj at the output of the rectifier decreases, In the steady state operation, the change in voltage DO, and UQ during the pause time is equal to the change in the indicated voltage for the duration of the pulse current load component

At time t, the current I of the inverter oscillating circuit approaches zero, diodes 5 and 6 turn off, and the voltage on thyristors 1 and 2 and diodes 5 and 6 is restored.

At time t, the voltage across the diode thyristor 30 increases to a value equal to the switching voltage and when it is unlocked again, electromagnetic processes in the converter circuit proceed similarly to the processes when the thyristors 1 and 2 are unlocked. However, the direction of the current pulses through the inverter circuit, the transformer winding and the additional oscillatory contour is reversed.

The period of current pulses at the output of the master oscillator is equal to the sum of the natural oscillation period of the circuit formed by the reactor 43 and capacitor 44, and the time delay for unlocking the diode thyristor 30 in the absence of a load at the converter output or the sum of the duration of the load current pulse and the time of decay pulse current load to zero. In this case, the delay time for unlocking the anode thyristor of the master oscillator is equal to

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pause of the following pulses of the load current and does not depend on its size.

With a constant pause of load current pulses, the dependence on load current of the recovery time of thyristor control decreases. As a result, the amplitude of the oscillating circuit current of the inverter in the absence of saturation of the transformer magnetic circuit is reduced to a value equal to twice the maximum value of the transformer open circuit current,

5 Thus, the invention makes it possible to ensure the continuity of the pause time of the inverter load current, to reduce the amplitude of the current pulses in the oscillating circuit of the inverter and, consequently, to reduce the no-load losses of the constant-voltage converter to constant,

Claims (1)

5 Invention Formula A device for controlling a constant-voltage converter constant on a bridge Q full-wave thyristor autonomous voltage inverter with a switching LC circuit, output loaded on the primary winding of a power transformer, the secondary winding of which is connected to the rectifier through an additional LC circuit containing a pulse distributor whose outputs are intended for connecting pulse transformers to them thyristor control electrodes, and the input through a current transformer is connected to the output of a relaxation generator, made on a diode thyristor, by an anode along connected to the pole output of the power source, and the cathode connected in series to the primary winding of the current transformer and time to the drive capacitor, characterized in that, in order to reduce the no-load losses of the converter, it is equipped with a current regulator made on the transistor, the second and third current transformers, oscillatory LC-circuit of the base circuit, a pulse key, performed on oppositely connected in parallel to the diode and thyristor, and the rectifier, and the primary five five 0 55 the winding of the second current transformer is connected to the circuit between the output time of the capacitor capacitor and the minus bus of the power supply source, the current regulator is connected to the common connection point of the first current transformer and the reference capacitor emitter circuit is connected to the first output capacitor of the oscillating LC circuit - pa of the base circuit, the anode of the diode and the cathode of the thyristor pulse key and the second output of which is connected to the first input of the current stabilizer, to the thyristor anode, cathode of the pulse key diode and through a resistor to the positive power supply bus, the second input of the current stabilizer through the zener diode is connected to the output of the rectifier, the input of which is connected to the secondary winding of the third current transformer whose primary winding is included. successively in the secondary circuit of a power transformer, secondary winding minus bus power source, The second terminal of the oscillator – IS capacitor of the second current transformer of the connected LC coitur is connected to the first terminal to the control transitions with the inductor element of the pulse switch contour. Fla.Z the second output of which is connected to the first input of the current stabilizer, to the thyristor anode, cathode of the pulse key diode and through a resistor to the positive power supply bus, the second input of the current stabilizer is connected via a zener diode to the output of the rectifier whose input is connected to the secondary winding of the third current transformer whose primary winding is included. successively in the secondary circuit of a power transformer, secondary winding