SU1577033A1 - Half-bridge inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in the design of secondary power sources. The goal is to increase reliability by simplifying the circuit. The device is made according to a half bridge circuit on power transistors 18, 19, the control transitions of which are connected to the secondary windings 4, 5 of the transformer 3 of the main pulse generator. The secondary windings 10-13 of the output transformer of the additional pulse generator serve to eliminate the through currents in the circuit and force the power transistors 18, 19 to turn off. In order to force the switching processes to the closing power transistor, a blocking voltage is applied that is close to the maximum permissible voltage, and the voltage supporting the opposite power transistor in the closed state is chosen of small size, which improves the process of their inclusion. 2 Il.

Description

FIG. one

The invention relates to a converter technique and can be used in direct-current or variable-frequency converters with an intermediate link of increased frequency.

The purpose of the invention is to increase reliability by simplifying the circuit.

FIG. 1 shows the layout of the inverter rack; in fig. 2 shows voltage diagrams explaining the principle of generating control signals for power transistors.

The inverter (Fig. 1) contains a master oscillator 1, the main driver 2 pulses with an output transformer 3 having secondary windings 4 and 5, an additional driver 6 pulses connected to the outlets of the two elements 7 and 8 coincidence, 9 and with secondary windings 10–13 through 4% diodes 14–17., Which are connected to Vche manus power transistors -8 and 19, the power circuits of which are shunted by sensors 20 and 21 of the state of the transistor. Sensors 20 and 21 are made on photo-emitters 22 and 23, photo-receivers 24 and 25, and output nodes 26 and 27.

FIG. 2 shows voltages: 28 at the forward output of the master oscillator; 29 - on the windings 4 and 5 of the transformer 3 of the main pulse generator; 30 and 31 at the outputs of the transistor state sensors; 32 - on the windings of the transformer 10 additional pulse shaper; 33 and 34 — power transistor control 18 and 19.

The operation of the inverter is as follows.

Let us assume that at time t (switching of master oscillator 1 occurs and voltage 29 on the output windings of transformer 3 changes polarity so that the previously closed transistor 18 starts from voltage winding 4 and the open transistor 19 is in the locking polarity. Due to the resorption process of excess carriers from the base region, the transistor 19 does not instantly close, therefore signal 1 is applied to both inputs of the coincidence node and a voltage 32 is formed at the output windings 10-13. The windings of transformer 9 are made in such a way that the windings of windings 10 and 11 are close in magnitude to the maximum allowable voltage of the base – emitter junction of the power transistor, and the voltage on windings 12 and 13 is slightly greater than the voltage drop on diodes 16 and 17. Under the action of voltage 32, diodes 15 and 16 are open. Voltage 33 is applied to the closed transistor 18, which maintains the transistor 18 in the closed state, and voltage 34, which ensures the forced closing of the transistor 19.

At the time t, the transistor 19 is closed and from the output of the state sensor 21 is supplied to the element 7 of the OA co-operation. At the first input of the element 8, coinciding with the inverse output of the master oscillator 1, the signal O is generated at the output windings of the transformer 9. At the same time, the transistor 18 opens and b., the second input of the element 8, coinciding with the sensor 20 of the state of the transistor 18, receives a signal 1.

At the moment of time t 3, the output signal level of the master oscillator changes and the first input of the element 8 coincident with the inverse output of the master oscillator receives the signal 1. The output windings 10-13 of the transformer 9 begin to form a voltage 32. Under the action of the voltage on the winding 10 the transistor 18 starts to turn off forcefully, and the voltage on the winding 13 does not allow the transistor 19 to open until the transistor 18 is completely turned off, despite the fact that a voltage 29 in the opening polarity is formed on the winding 5. At time t, the transistor 18 is closed, and then the operation of the circuit is carried out similarly.

Thus, at the points in time when the excess carriers of the power transistors are resorbed, voltages of different magnitudes are applied to their base-emitter transitions. The base-emitter transition of the transistor, which was previously closed, is supplied with a voltage of the order of (0.3-0.5) V, and an open (4-6) V in the locking polarity. Under the action of the closing voltage is forced to turn off the open transistor

and, thereby, the key.

51577 (333

acceleration of the invention process

A half-bridge inverter containing power transistors, the control inputs of which through the base resistors are connected to the secondary winding of the transformer of the main pulse generator, the input connected to the outputs of the master oscillator connected to the first inputs of the matching elements, the outputs connected to the input of the additional pulse generator with the output transformer, secondary windings which through the first diodes are connected to the control

inputs of power transistors, the power circuits of which are connected to transistor state sensors, characterized in that, in order to increase reliability by simplifying, the outputs of transistor state sensors are connected to the second inputs of the matching elements, and the input transformer secondary windings are connected in parallel to the control inputs of the power transistors additional pulse former through the entered second diodes, while the direction

the conductivities of the first and second diodes and the control transitions of the power transistors of the tori are consistent, and the polarity of switching on the secondary windings of the specified transformer is opposite.

FIG. 2

Claims (1)

Claim A half-bridge inverter containing power transistors, the control inputs of which are connected through the base resistors to the secondary winding of the transformer of the main pulse shaper, connected to the outputs of the master oscillator, connected to the first inputs of the matching elements, the outputs connected to the input of the additional pulse shaper, secondary outputs with an output transformer, windings of which are connected through perp to the control inputs of power transistors, whose power circuits are connected to dates transistor status indicators, characterized in that, in order to increase reliability by simplifying, the transistor status sensors outputs are connected to the second inputs of the matching elements, and the input secondary transformer windings of the additional pulse former are connected via the second diodes in parallel with the control inputs of the power transistors, while the direction of conductivity the first and second diodes and control transitions of power transformers _{t of} consonants, and the polarity of the inclusion of the secondary windings of the specified transformer opposite.