SU1705992A1 - Inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply and automation systems. The purpose of the invention is to increase the efficiency. In the half-bridge inverter, the first transistor 1 is selected bipolar, and the second transistor 5 is field-effect. Due to diodes 9 and 10, connected in the direction of conducting the current, closing the transistors 1 and 5, the transistors quickly turn off, which is also facilitated by the winding of the positive feedback of the output transformer 2. Turning on of the transistor 5 is delayed due to recharge of its input capacitance through the resistor 8. Due to this, the through current during switching of transistors 1 and 5 is eliminated and the dynamic power losses dissipated in them are reduced. 1 il.

Description

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The invention relates to electrical engineering and can be used in secondary power supply and automation systems.

The purpose of the invention is to increase efficiency.

The drawing shows a schematic diagram of the inverter.

The inverter contains a bipolar transistor 1, a transformer 2, two capacitors 3 and 4, a field-effect transistor 5, three resistors 6, 7 and 8, two diodes 9 and 10, and a control unit 11. The primary winding of the transformer 2 is connected to the first terminals of capacitors 3 and 4 by its first extreme terminal, to the first terminal of the first resistor 6 by the second extreme terminal. One input terminal of the inverter is connected to the collector of transistor 1 and the second terminal of the capacitor 3. The second input terminal of the inverter is connected to the source field-effect transistor 5 and the second output of capacitor 4. The base of transistor 1 is connected to the anode of diode 9, the second output of resistor 6 and the first output of resistor 7, the second output of which is connected to the first output of control unit 11 and the cathode of the diode 9. The second output of the control unit is connected to the cathode of diode 10 and the first lead of the resistor 8, the second lead of which is connected to the gate of the field-effect transistor 5 and the anode of the diode 10.

Resistors 6, 7, and 8 are current-limiting elements that determine the opening processes of transistors 1 and 5. Diodes 9 and 10 increase the closing speed of transistors 1 and 5.

As a transistor 1 can be used with a static induction transistor (SIT). A feature of the SIT is that it is in the open state at zero voltage on its gate.

In the absence of control signals at the outputs of the control unit 11, transistor 1 is closed and transistor 5 is open. The closed state of transistor 1 ensures the absence of a through current.

When the control voltage Uynp.1 arrives at the first output of control unit 11 and Uynp.2 at the second output of control unit, transistor 1 opens and transistor 5 closes. Since transistor 5 has a high speed and its input capacitance is charged through the forward-mounted diode 10, it closes faster than the transistor 1 opens. Unlocking of transistor 1 is forced due to the positive feedback winding created by additional coils of primary transformer windings. The more the current flowing through the transistor 1 changes, the greater the opening voltage on the additional part of the primary winding of the transformer 2. In this case, the capacitor 3 is discharged and the capacitor 4 is charged. Therefore, in this mode the through current is minimal, since the transistor 5 closes faster than transistor 1 opens.

Upon receipt of the locking Uynp.1 and unlocking Uynp.2, transistor 1 closes and transistor 5 opens. The resampling of the input capacitance of the transistor 5 occurs through the resistor 8, the resistance of which largely determines the time after which the transistor 5 opens. The voltage Uynp.1 applied to the base of transistor 1 through the shifted diode 9 closes the transistor 1. As soon as the current in the primary winding of the transformer 2 starts to change when the transistor 1 is locked, transistor 1 is forcedly closed due to positive feedback. In this case, the capacitor 3 is charged and the capacitor 4 is discharged. Thus, the through current is minimal, since transistor 1 closes faster than transistor 5 opens. After the switching process of the transistors is completed, the static losses due to the low resistance of the channel of the field-effect transistor 5 are small.

Low power losses, both when switching transistors. And in the static state when the field-effect transistor is open, increase the efficiency of the device.

Claims (1)

Invention Formula An inverter comprising first and second transistors and two capacitors connected in half bridge, as well as an output transformer with a primary winding connected to the output terminals and a positive feedback winding connected through the first resistor to the input of the first transistor, characterized in that to increase efficiency. The first transistor is selected as a bipolar, and the second transistor is a field transistor; the control circuits of the first and second transistors are connected to the corresponding outputs of the inserted control unit through the second and third entered resistors, respectively, each of which is shunted by an input diode connected to the opposite conductivity of the input transistor circuit,