SU1610572A2 - Bridge-type transistor inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and automation systems. The purpose of the invention is to enhance the functionality by reducing the residual output voltage in the off mode. The inverter contains power transistors 7 and 8 and control transistors 11 and 12 connected in a bridge circuit. The control transistors 11 and 12 are switched by the output signals of the pulse generator 15. The power transistors 7 and 8 are automatically locked by the bias diodes 9 and 10 when the control transistors 11 and 12 are unlocked and vice versa when they are locked. The source for unlocking the power transistors 7 and 8 are rectifiers in the form of isolating diodes 1 (2) and capacitors 5 (6). Compensating diodes 18, 19, streamlined by the current passing through the auxiliary resistor 20, are connected via a shunt diode 16 and 17 to the load circuit. The voltage drop across the compensating diodes 18 and 19 reduces the output voltage of the inverter to zero to almost zero, while the control transistors 11 and 12 are open. 1 sludge.

Description

The invention relates to electrical engineering and can be used in secondary power supply and automation systems.

The purpose of the invention is to enhance the functionality by reducing the residual output. voltage off mode.

The drawing shows a schematic diagram of the inverter.

The inverter contains isolating diodes I, 2, connecting current limiting resistors 3, 4 and capacitors 5, 6 with a positive input terminal (+ E) s. The collectors of power transistors 7, 8 are connected to this terminal, forming a circuit for flowing the load current through the bias diodes 9, 10 and the control transistors 1 1, 12. The bases of the transistors 11 and 12 are connected via diodes 13, 14 to the outputs of the generator 15 and the two shunt diodes 16, 17 connected by anodes to the output terminals of the inverter, and the combined cathodes - to the anode of one of the according-follow Tel'nykh connected compensating .diodov 18, 19, connected

One 9 and a transistor 11, keeps the closed-loop transistor 7. When changing the voltage at the outputs of the generator 15, the transistors 7, 12 are opened, and the transistors 8, 11 are closed.

When the inverter operates in the mode of regular switching power and control

Q of the transistors, the newly introduced elements have no effect on the operation of the circuit.

Upon transition of the input signal U | ,,, p from high potential to low

JV5 (zero) at the outputs of the generator 15, signals appear that open both control transistors 11, 12. At this time, the storage energy in the load inductance (magnetizing

2Q current) is discharged along a circuit depending on the previous open state of the transistors, i.e., the direction of the flow of the magnetizing current at the time of the inverter turning off. If a

25 for example, when transistors 7 and 12 were open, then after the inverter was turned off, the magnetizing load inductance current would flow through diode 16, diode 10, transistor through an additional resistor 20, and the diodes 18, 19. voltage on diodes 18 and 19

It is seen from the sum of the voltage drops on the elements 16, 10, 12, if the inductive magnetizing current of the load circuit is less than the current passing through the resistor 20.

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The inverter works as follows.

When the power supply is turned on: in the absence of an input signal, both the control transistors 11, 12 are open and are in the down state, and the power transistors 7, 8 are closed or due to the voltage of the diodes 9, 10 during the flow through them, charge currents 7 of the capacitors 5, 6, or due to the absence of base currents after charging the capacitors 5, 6.

When the control signal arrives at the inverter input, impulses of antiphase voltages appear at the outputs of the generator 15, alternately opening 1x and closing the control transistors 11 and 12. When transistor 11 opens, the power transistor 8 opens, as a circuit is created to flow the base transistor current due to the discharge of the capacitor 6 through the resistor 4 and the base-emitter junction of the transistor 8. The load current flowing through the transistor 8 is di-

One 9 and a transistor 11 hold the transistor 7 in a closed state. When changing the voltage at the outputs of the generator 15, the transistors 7, 12 open, and the transistors 8, 11 close.

When the inverter operates in the alternate switching mode of the power and control transistors, the newly introduced elements do not affect the operation of the circuit.

Upon transition of the input signal U | ,,, p from high potential to low

(zero) at the outputs of the generator 15, signals appear that open both control transistors 11, 12. At this time, the storage energy in the load inductance (magnetizing

current) is discharged along a circuit depending on the previous open state of the transistors, i.e., the direction of the flow of the magnetizing current at the time of the inverter turning off. If a,

For example, if transistors 7 and 12 were open, then after the inverter is turned off, the magnetizing inductance current of the load will flow through diode 16, diode 10, transistor,

  and diodes 18, 19. At the same time, the voltage drop across diodes 18 and 19

o and diodes 18, 19. At the same time, the voltage drop across diodes 18 and 19

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It is seen from the sum of the voltage drops on the elements 16, 10, 12, if the inductive magnetizing current of the load circuit is less than the current passing through the resistor 20.

In this case, the voltage on the load will be almost zero since the voltage drop on diodes 16 and 10 is compensated by the voltage drop on diodes 18 and 19, and only the voltage on the transistor 12, which is in saturation mode, remains uncompensated.

Claims (1)

Invention Formula Bridge transistor inverter aBTi evo no. 773876, characterized in that, in order to expand its functionality by reducing the residual output voltage of the off mode, two shunt diodes, two compensating diodes and an additional resistor are inserted, and the compensating diodes are connected in series to form a chain one connected to the emitters of the control transistors, and the other 516105726 Through the additional conduction compensation, the compensator compensates with the collectors of the power transducer diodes and coincides with the direction resistors, and through each shunt of the conductivity of the control transistor diode - with the corresponding output level, and the direction of conduction of the converter's output, while the imitating diodes are opposite to it.