SU1607064A1 - Semi-bridge inverter - Google Patents

Abstract

The invention relates to electrical engineering and can be used in secondary power supply systems. The purpose of the invention is to increase efficiency and reliability by providing protection against end-to-end and inverse transistor currents. Transistors 2 and 3 are controlled by current transformers 4 and 5. The control windings 17 and 20 of current transformers 4 and 5 are connected at the output of a pulse shaper 13, to inputs A-D of which are output signals A and B of current sensors 14 and a master oscillator 12. The current of the primary windings 22 and 23 of the current sensors 14 passing through one of the open transistors 2, 3 and recuperative diodes 6 and 7, before switching the transistors 2, 3, creates, using a pulse generator 13, the switching on of the corresponding transistor 2, 3, providing their protection from penetrating and inverse currents. 1 hp f-ly, 1 ill.

Description

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

The purpose of the invention is to increase efficiency and reliability by providing protection against through and inverse current transistors.

The drawing shows a circuit diagram of an inverter.

Half-bridge inventory contains power amplifier 1 with transistors 2 and 3, controlled by current transformers 4 and 5. The recovery diodes 6 and 7 are connected to the input terminals of the power amplifier 1, the output of which is connected to the primary winding of the output transformer 8. The secondary windings of the output transformer 8 through the inputs of the power diodes 9 and 10 and the filter 11 are connected to the output terminals of the converter. The block contains a master oscillator 12 and a driver for controlling impulses 13. The current sensor 14 is the first and second, output A and B is connected to two inputs of the driver 13 pulses. The input circuit of the sensor 14 is connected in series with the transistors 2 and 3 of the amplifier 1 power. For switching of the transistor 2, the current transformer 4 contains a primary 15, a base 16 and. the control winding 17, and for switching the transistor 3, the current transformer 5 also contains a primary 18, a base 19 and a control winding 20. Winding 17 and 20 are connected to the outputs of the imaging unit 13 pulses. The other terminals of the regenerative diodes 7 and 6 are connected respectively to the points a and b of the connection of the opposite power transistors 2 and 3 of the power amplifier 1 with the input circuits of the current sensor 14. The current sensor contains a transformer 2 Current with primary 22 and 23 and secondary 24 and 25 windings, loaded with each of the secondary half windings through rectifying diodes 26 and 27 by resistors 28 and 29, which produce unipolar voltage pulses proportional to the collector currents of transistors 2 and 3, Separating diodes 30 and 31 are switched on according to the OR scheme to form a signal of the current sensor, which is fed to the master oscillator 12. The outputs of the rectifying diodes 9 and 10 through the power choke 32 (through its oppositely connected devices 33 and 34) are connected to the capacitor 35 of the LC filter 11. The damping circuit of the series-connected resistors 36 and the capacitor 37 is connected parallel to the input of the power throttle 32.

Half-bridge inverter operates as follows.

The generator 12 generates two sequences of pulse-width modulated pulses that are out of phase by 180 ° relative to each other. These pulse sequences are fed to the main inputs C and D of the pulse driver 13 so that, through the control windings 17 and 20 of the current transformers 4 and 5, the power transistors 2 0 and 3 of the power amplifier 1 are switched with the duty cycle required to maintain the output voltage of a constant to us.

Consider the switching processes in the half-bridge converter when the fill factor of the control pulses of the power amplifier 1 to 5 is approached, i.e. when the half-bridge converter operation mode is similar to the unregulated converter operating on an output rectifier with an LC filter.

Suppose, before switching, the power transistor 2 is open, held in the open state by positive feedback between the primary 15 and the base 16 5 windings of the current transformer 4. Consequently, the collector current of this transistor, flowed through the primary winding 22 of the current transformer 21 will be transformed along the circuit: secondary winding 24, 0 rectifying diode 26 and resistor 28. At the last through voltage pulse of positive polarity proportional to the collector current of the power transistor 2 The voltage from this arm 5 of the matching part of the protection and blocking units is fed to one of the auxiliary inputs B of the driver of 13 pulses for duplicating the signal on the main input G in order to hold the 0 3 transistor in the locked state by turning on the control winding 20 of the transformer 5

current.

Simultaneously with switching on the power transistor 2, a rectifier 45 diode 9 opens, allowing the load of the half-bridge inverter to pass through the half winding 33 of the power throttles 32 of the output LC filter 11. When 12 pulses are received from the generator to turn on input B of the equal winding 17 of the transformer 4 and input for disconnecting at the G input of the formaker 13 pulses of the control winding 20 of the current transformer 5, the food is eaten by the southwestern. the ear. Immediately after their submission is included

55 the control winding 17 of the current transformer 4 for locking the power transistor 2, and turning off the control winding 20 of the current transformer 5 is blocked by the signal on the auxiliary input B of the driver of 13 pulses due to the presence of a step

dissolving when turning off the transistor 2 power amplifier 1. Consequently, during this stage, due to the flow through the primary winding 22 of the current transformer 21 of the collector current of the power transistor 2, the auxiliary input B of the pulse former 13 will receive a signal to block the control winding 20 of the current transformer 5 to eliminate the through-current of the Inventor transistors.

After the resorption stage is completed, the front voltage of the power rectifier begins to form. At this time, the energy accumulated during the previous half-period in the output transformer 8 is discharged to the power supply through the recovery diode 7, the primary winding 22 of the current transformer 21 and the primary winding of the output transformer -a 8. Consequently, at the so-called inverse current stage, the input B of the pulse shaper 13 pulses will have a positive voltage that blocks the control winding 20 from turning off transformer 5 current, prohibiting the inclusion of the power transistor 3 in the investment mode.

The inclusion of the power transistor 3 of the power amplifier 1 occurs after the fall of the inverse current in the primary semi-winding of the current separation transformer 21. This forms a reverse polarity at the input of the power rectifier, which opens rectifying diode 10 when rectifying diode 9 is still closed. When connecting rectifying diode 10 to secondary winding 34 of power drossel 32, the switching current of auxiliary diodes 9 and 10 is limited by inductance dissipation of power droplets 32 when turning on its windings 33 and J4 is opposite.

40 45 50

The resistor 36 and the capacitor 37 damp the high frequency emissions of the voltage arising from the switching of the windings of the transformer 8 and drossel 32.

After turning on the transistor 3 of the power amplifier 1, its collector current flows through the primary winding 23 and is transformed into the secondary winding 25 of the current transformer 21 and creates a positive polarity voltage drop across the second resistor 29. The voltage from the output A of the current sensor 14 is fed to the driver input A 13 control pulses for blocking the activation of the control winding 17 of the current transformer 4 of the transistor 2, which locks it into all stages of the half-cycle of conversion.

Simultaneously with supplying inputs A and B of a shaper 13 voltage pulses from resistors 28 and 29, it goes through dividing diodes 30 and 31 to the input of master oscillator 12. In order to convert the inverter into each half-period when the collector currents of a certain level exceed set a blocking potential at the protective input D of the pulse shaper 13 for the mandatory switching on of both control windings 17 and 20 and for locking the power transistors 2 and 3.

Image formula

Claims (2)

1. A half-bridge inverter containing 0 two transistors, each of which is equipped with a control current transformer with a primary winding connected in series with the transistor, a base winding. connected between the base and the emitter of the transistor, and the control winding connected to the corresponding output of the control unit, the first and second current sensors, each of which along the input circuit is connected in series with the corresponding transistor, and the connection point of the input current sensor circuits is connected to each other to the output terminal of the inverter, the output of each current sensor is shunted by a resistor and through a separating diode b is connected to the input of the protection node, the output of which is connected to the first input of the control unit; which provides both transistors off trench, wherein. that, in order to increase efficiency and reliability by providing protection against the transient and inverse current of the transistor, two transducer switch-on interlocks are connected to the control unit, connected to the second and third inputs of the control unit, to which the outputs of the first and second current sensors are connected , and an antiparallel circuit consisting of the corresponding transistor and the input circuits of both current sensors included an inserted recovery diode. 2. The inverter according to claim 1. that both current sensors are made in the form of a common transformer with two counter-connected primary windings, which cut off the current sensor input circuits, and two according to the included windings connected to the current sensor output terminals via rectifying diodes