RU1836798C - Dc-to-ac inverter - Google Patents

Abstract

Usage: in industrial electronics. SUMMARY OF THE INVENTION: the device is made according to a half-bridge circuit of the inverter, the primary trans 2,5 windings: formatododes are included in the collector circuits of transistors 4, 6. When switching transistors 4, 6 during saturation of transformer 3, the inrush currents in each arm are limited, and the voltage applied to each of the transistors is reduced, which improves reliability. 1 ill. HY 7-122 8:00 a.m. from -4J o 00 CJ

Description

The invention relates to electronic equipment, in particular to transistor DC / AC converters, and can be used in industrial electronics.

. The aim of the invention is to increase reliability.

The drawing shows a circuit diagram of a single-phase push-pull inverter with self-excitation .. ... The device includes a power source, to the positive pole of which the end of the primary winding 2 of transformer 3 is connected. The beginning of which is connected to the collector of transistor 4, the emitter of which is connected to the beginning of the primary winding 5, the end of which is connected to the collector of another transistor b, and the emitter of transistor 6 is connected to the negative pole of power supply 1, each transistor 4.6 with a connection hydrochloric its collector to half of the primary winding respectively corresponding 2,5 shunted capacitors 7, 8, the end of the excitation coil 9 is connected via a resistor. 10 to the base of transistor 4, the beginning of which is connected through parallel-connected resistor 11 and capacitor 12 to the emitter of transistor 4, and the beginning of the second field winding 13 is connected through resistor 14 to the base of transistor 6, the end of which is connected through parallel-connected resistor 15 and capacitor 16 to the emitter transistor 6, and between the positive pole of power supply 1 and in parallel, resistor 11 and capacitor 12 are connected, resistor 17 is connected, and between resistor 11 and capacitor 12 in parallel, and parallel connected resistor 18 is connected with resistor 15 and capacitor 16, each transistor 4 and 6 are shunted by diodes 19 and 20, respectively, and the anode of each diode is connected to the emitter of the transistor, and the cathode is connected to the collector of the corresponding transformer 3, the load 22.

The device operates as follows. Suppose that at time t the transistor 4 is open and saturated, and the transistor 6 is completely closed and is in cutoff mode. The initial state is maintained by a linear increase in the magnetic flux in the core of the transformer 3 until it becomes saturated, after which the polarity changes on the windings transformer 3 and opening the transistor 6, and the transistor 4 is closed, after which the magnetic flux decreases to maintains a changed polarity by

windings. When saturation of the core of the transformer 3 on the other half of the hysteresis loop is achieved, the process of changing the polarity on the windings of the transformer 3, etc. The polarity on the windings of the transformer 3 is shown in FIG. 1 (the first half-cycle of the inverter or its initial state-polarity is plotted without brackets, the second half-period 0 in brackets). In the first half-cycle, current flows through an open transistor 4, a capacitor 8, which shunts a closed transistor 6, with a series-connected half-winding 5, and through a power source 1, in the second - through a capacitor 7, which shunts a closed transistor 4 with a half-connected half-winding 2, through an open transistor 6 and a power source

0 1. Diodes 19 and 20 are designed to eliminate negative voltage spikes on transistors during switching times.

In the proposed single-phase push-pull, 5th inverter each, its arm also works without inrush currents as well. analog, but the applied voltage to the transistor is two times less than that of the analog. In the prototype, the transistor currents during

0 saturation of the transformer 3 jump increase to very large values. Such an effect can lead to a frequent exit of transistors.

It should also be noted that the claimed

5 device can 4 work with external control.

The prototype of the device has passed laboratory tests. It used transistors type KT839A, capacitors

0 type K78-4, 0.47 μF, 500 V. K72-9.1 μF, 300 V, resistors type MLT-0.5 W, 300 Ohms, 100 Ohms, 2 W, 47 kOhm, diodes type 2D220I, inverter parameters :

Operating frequency 5000 Hz

5 Voltage at 10 V

Claims (1)

Rated power 25 watts. SUMMARY OF THE INVENTION DC / AC converter made according to the oscillator circuit with a capacitive input voltage divider and output transformer. the feedback windings of which are connected to the control circuits of transistors, with the exception of the fact that, 5, in order to increase reliability by reducing current overloads, the primary winding of the output transformer. made in the form of two sections, counter-included in the collector circuits of transistors, each consecutive connection of the transistor and the section winding of the connected parallel-resistive voltage divider, medium the corresponding capacitor is a capacitor - the point of which is connected to the output of the circuit th input voltage divider, sub-control of the corresponding transistor. 5