SU1317622A1 - Semibridge self=excited transistor inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and electric drive systems to convert DC voltage to AC. The goal is to increase efficiency in a wide range of load current variations. The device is made according to a half bridge circuit on transistors 3 and 4 and capacitors 1.2. A chain of two parallel-connected diodes 9, 10 and a resistor 8 is connected in series with the winding 6 of the transformer 7. One of the positive feedback winding terminals 15 is connected to the bases of transistors 3.4 and the other to the collectors of transistors 13 and 14. Introduction of transistors 13 and 14 allowed us to accelerate the avalanche-like switching process of transistors 3 and 4 by organizing current feedback. 1 il. c (L vl Oh go th

Description

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 The invention relates to electrical engineering and can be used in secondary electrical power supply systems and electric drives for converting constant voltage to alternating voltage.

The purpose of the invention is to increase the SM in a wide range of load current variation.

The drawing shows a diagram of the proposed inverter.

The inverter contains capacitors 1 and 2 and transistors 3 and 4, forming a bridge, in one diagonal of which a constant voltage source 5 is connected, and in the other diagonal is the primary winding 6 of the transformer 7 o In series with a winding 6 a chain consisting of current-measuring resistor is included 8 and pairs of anti-parallel connected diodes 9 and 10. In parallel to this circuit, two are included. a chain consisting of base resistors 11 and 12 and base-emitter transitions of transistors 13 and 14, respectively. The connection point of the collectors of transistors 13 and 14 through the winding 15 of the positive feedback of the transformer 7 is connected to the connection point of the bases of transistors 3 and 4. The output winding 16. of the transformer 7 can be, for example, through the rectifier 17 connected to the load 18 bounded by a capacitor nineteen.

The inverter works as follows.

Let the leakage current of transistor 3 be slightly greater than the leakage current of transistor 4. When the power is supplied diagonally across the bridge, consisting of the primary winding 6 of transformer 7, resistor 8 and diode 9, the differential current will flow. The current flow of transistor 3 through the circuit diode 9 - resistor 8 creates unlocking voltage for transistor 13 and blocking voltage for transistor 14. Base current of transistor 13 defined by resistor 11, amplified by transistor and across collector circuit of transistor 13 - winding 15 of transformer 7 - base of transistor 3 unlocks the last one. The increase in the collector current of the transistor 13 leads to a further opening of the transistor 13, due to the PolNIIPI Order 2432/53 Circulation 660 Subscription Frequency-Polyr. pr-tie, Uzhgorod, st. Project, 4

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positive feedback, the process of avalanche opening of the transistor 3 occurs. When the core of the transformer 7 is open,

The feedback is broken, the transistor 13 starts to close, on the windings of the transformer 7 an EMF of opposite polarity appears. This leads to the rapid switching on of transistors 13 and 3 and the switching on of transistors 14 and 4. Further operation of the converter occurs in the same way as described. The base current of the transistor 13 (14) op

is determined by the voltage drop across the resistor 8 and, therefore, the load current of the inverter. Consequently, the current of the winding 15 and the base current of the power transistor 3 (4) are directly proportional to the load current, t, e. current feedback is performed, which increases the efficiency of the inverter over a wide range of load current variations.

Claims (1)

Invention Formula A half-bridge self-exciting transistor inverter containing two power transistors of different conductivity type, connected according to the half-bridge circuit and connected to each other by E1 itters and bases and an output transformer with positive feedback winding connected by one output with bases of power transistors, characterized in that, in order to increase efficiency in a wide range of load current, between the emitters of the power transistors and the output of the primary winding of the output transformer included a chain of series-connected current-measuring diodes and two pairs. control transistors. of a different type of conductivity, the collectors of which are combined and connected to another terminal of the positive feedback winding, emitters also connected and connected to the emitters of power transistors, and the base through the input resistors connected to the output of the primary winding of the output transformer.