SU1264281A1 - Transistorized self-excited inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in power supply and automation systems to convert DC voltage to AC. The purpose of the invention is to increase the efficiency by sim-i metric of the mode of magnetization reversal of the core of the output transformer. The device contains power transistors 1.2, connected according to the inverter circuit with current feedback. A current stabilizer 10 is connected to the base circuit of each of the transistors, the operating mode of which is chosen so that during the flow of rated currents it is outside the current stabilization zone . An increase in the jDo6oro current from transistors above a given value leads to a limitation of the current consumed from the current transformer and to the stabilization current stabilizer current mode 10, which leads to a faster reversal of the S-core and switching of the transistors. Re (The operation of the current transformer becomes asymmetrical, the operating mode of the transistors and the output transformer is symmetrical, and the dynamic losses are reduced. 3 Il.

Description

The invention relates to electrical engineering and can be used in power supply and automation systems to convert DC voltage to AC.

The purpose of the invention is to increase the efficiency by balancing the mode of remagnetization of the output transformer core.

Figure 1 shows a circuit diagram of an inverter; in Fig.2 and 3 current stabilizer current-stabilizing two-port.

The transistor self-exciting inverter (Fig. 1) contains power transistors 1 and 2, a current transformer 3 and an output transformer 4. The collectors of transistors 1 and 2 through the primary windings 5 and 6 of the current transformer 3 and the primary windings 7 of the output transformer 4 are connected to the first input supply terminal Inverter, and the emitters are combined and connected to the input terminal of the inverter. The secondary windings 8 and 9 of the current transformer are connected parallel to the input of transistor 1 and 2. A current stabilizer 10 is connected in series to the base circuit of each transistor. The specific implementation of current stabilizer 10 is shown in FIG. (Bipolar transistor) and in FIG. 3 (field effect transistor).

The inverter works as follows. I

When a voltage is applied to the input, a constant voltage is shifted to the bases of transistors 1 and 2. When the parameters of transistors 1 and 2 are unbalanced, one of the transistors opens and the other closes as an avalanche. The current through the transistor 1 increases, which causes an increase in the current in the base winding of the current transformer 3. Transistor 1 enters saturation mode and an input voltage Vc is applied to the winding 7 of the output transformer 4, which is transformed and enters the load. Transistor 1 is in the onstage mode as long as current transformer 3 is in the linear portion of the hysteresis loop. When entering saturation mode, the voltages on the windings decrease like an avalanche, as a result of which transistor 1 becomes closed and transistor 2 opens.

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The collector current, which flows through the winding 6 of the current transformer 3, is transformed into the winding 9, providing the necessary saturation of the transistor.

S The mode of operation of the current stabilizer 10 is chosen such that when the rated currents flow, it is outside the current stabilization zone and any increase in current from idle

10 stroke to nominal leads to an increase in current through the stabilizer 10 current. In this mode, the current transformer 3 performs the function of a positive feedback positive-voltage transformer, the voltage drop on windings 5 and 6 is insignificant and is determined by the voltage drop on the emitter junction and on the current stabilizer 10. Increase

20 current through any of the switching transistors above a predetermined value leads to a limitation of the current consumed from the current transformer and to the output of the stabilizing current of the current regulator 10. On the winding 5 or 6 of the current transformer 3, an increase in the voltage and a faster alternating magnetization of the core, and, consequently, switching

30 transistors.

The excess current of one of the transistors can occur due to the asymmetric mode of operation of the output transformer 4, for example,

35 due to the difference in turns of the semi-windings of the winding 7 of the output transformer 4 or due to the scatter of the values of the parameters of the transistors. One of the transistor currents at the end of the half period

40 increases dramatically due to saturation of the core of the output transformer, this leads to an exit to the stabilization mode of the current stabilizer 10 and, consequently, to an increase in the drop

45 the voltage on the winding 5 (6), faster reversal of the core of the current transformer and the reduction of the half-cycle duration. The mode of operation of the current transformer becomes

50 asymmetrical, however, the operating modes of the transistors and the output transformer become symmetrical, and the dynamic losses are drastically reduced.

When a short circuit in the circuit 55 of the load, when the current increases through the windings 5 and 6 to the value at which the current stabilizer 10 enters the current stabilization mode.

3

Claims (1)

transistors 1 and 2 go out of saturation mode, and the current transformer 3 increases the voltage drop (current transformer switches to voltage transformer mode), the current through the primary converter circuit is limited to the value set in the current regulator 10. Invention Formula A current-feedback self-excited transistor inverter containing two power transistors, an overcurrent current transformer with two primary and two secondary windings and an output transformer with two primary windings, the collector of each transistor being connected in series 814 the primary windings of the current transformer and the output transformer are connected to the first input supply of the inverter, the emitters of the transistors are combined and connected to the second input of the inverter, and each secondary winding of the current transformer is connected to the input of the corresponding transistor, characterized in that, in order to increase the efficiency by balancing the mode of the remagnetization of the core of the output transformer, (two stabilizers, a current, each of which is made in the form of a gostabilizing two-port device and is connected in series to the base circuit of the power transistor.