SU508882A1 - Push-pull transistor inverter - Google Patents

Description

(54) TWO-TERM TRANSISTOR INVERTER

one

The invention relates to converter technology and can be used in automation and electric drive systems for converting a constant voltage to an alternating voltage of a controlled frequency.

The known transistor inverters with an output voltage frequency regulator and saturable transformers for controlling transistors have a significant delay in the frequency control process.

The purpose of the invention is to increase the speed of the inverter by the frequency control signal.

This is achieved by the fact that a first pair of anode-connected diodes is inserted into the proposed inverter, parallel to each of which the primary winding of the control transformer is connected through the feedback winding, and the second pair of cathodes connected to the diodes, the anodes of which are connected to the cathodes of the first pair of diodes, A control element is connected between the connection point of the inner part of the first pair of diodes and the connection point of the cathodes of the second pair of diodes.

As a control element, either an adjustable constant-current source, an adjustable constant-current source, a variable resistor, or a transistor can be used.

The inverter can be made both on the bridge and on the push-pull circuit with the middle point of the transformer.

FIG. 1 shows an inverter circuit in which the primary windings of saturable transformers are connected to the primary winding of an output transformer; in fig. 2 and 3 are inverter circuits with additional windings connected in series with the diodes.

The inverter works as follows. Control transformers 1 and 2 transmit pulses to the bases of transistors 3 and 4,

periodically opening and closing transistors. The duration of the pulses, and therefore the output frequency, is determined by the time required for the flow in the core of the corresponding control transformer to change from the initial lead to the value of the saturation flow. When the core is saturated, the voltage in the secondary winding of the transformer drops, which leads to rapid closing

open and open closed transistors. The magnitude of the initial magnetic flux of control transformers is varied by control source 5. After the magnitude of the control source, it can be changed in

wide limits of the initial flux in the cores of transformers I and 2, and, consequently, the output frequency.

The primary windings of the control transformers are separated by diodes 6-9 and connected with the power of diodes 6 and 7 to the windingM of the output transformer 10 in half-cycle when the corresponding transformer transmits to the transistor a voltage pulse opening this transistor and connected via diodes 8 and 9 through the source control signal in half-cycle, when the corresponding control transformer transmits a blocking voltage pulse to the transistor. This achieves a simplification of the circuit and ensures a high response rate when the frequency transitions from low to higher (in the circuit shown in Fig. 1), when the frequency transitions from low to high (Fig. 2) and from high to low (Fig. 3).

The transient process in the circuit (Fig. 1) is delayed as the frequency decreases, due to the fact that e. d. on the control element can have one significant magnitude polarity. Another polarity of this e. d. closes diodes 6-9. In the diagrams and indications of FIG. 2 and 3, e. d. The control element can have both one significant and great polarity and another in the process of the ivertor's operation, and this in turn provides for the transient response rate both at an increase in frequency and at a decrease in frequency.

Since the currents in the primary windings of the control transformers, when they apply the blocking voltage to the transistors, are small, therefore, the control signal current is low, and since in this case the power source is consumed, the signal source can be used resistor or transistor.

Claims (4)

Invention Formula A push-pull transistor inverter with an adjustable frequency output voltage containing an output transformer with feedback windings and two saturating control transformers, the secondary windings of which are connected to input transistors, characterized in that, in order to increase speed, a first pair of anodes are connected diodes, parallel to each of which the primary winding of the control transformer is connected through the feedback winding, and the second pair of diodes connected by the cathodes, the anodes are x coupled to the cathodes of diodes of the first pair, and the connecting point between the first pair of diodes the anodes and cathodes connecting point of the second pair of diodes included control element. 2. The inverter according to claim 1 is also distinguished by the fact that the anodes of the second pair of diodes with the cathodes of the first pair of diodes are connected directly. 3. The inverter according to claim 1, characterized in that the anodes of the second pair of diodes are connected to the cathodes of the first pair of diodes through the additional windings of the output transformer. 4. Inverter pop. 1, with the fact that the anodes of the second pair of diodes are connected to the cathodes of the first pair of diodes through the sections of the primary windings of the control transformers. fig a