SU995226A1 - Two-cycle inverter - Google Patents

Description

. (54) TWO-TIME INVERTER

one

The invention relates to converter equipment and can be used to power electronic equipment.

Voltage converters are known that contain power switches, a transformer, a rectifier and a smoothing filter 1.

The disadvantage of these converters is the presence of abrupt changes in the currents in the power circuits, resulting in significant switching losses, low reliability of the operation of the power switches, a high level of electromagnetic interference generated.

Closest to the present invention is a push-pull inverter containing the first and second power switches shunted by return diodes, a control unit connected to the control electrodes of the power switches, a transformer whose primary winding, the winding of the drossel and the main capacitor are connected in series to the secondary winding of the transformer connected rectifier with capacitive filter 2.

In the well-known inverter switching processes are smooth. but

Connecting the power switches in series complicates the control circuit, since galvanic isolation is required, and control losses increase. In addition, in the moments of switching are possible.

5 through-currents through power switches, which increases dynamic losses and reduces operational reliability.

The purpose of the invention is to simplify the device, increasing its efficiency and reliability.

to by providing a proportional-current control mode without galvanic isolation and eliminating the simultaneous unlocking of the power switches.

The goal is achieved by the fact that a two-stroke inverter containing the first

15 and the second power switches shunted by the return diodes, the control unit associated with the control electrodes of the power switches, the transformer whose primary winding, the throttle winding and the main capacitor are connected in series, the rectifier with a capacitive filter connected to the secondary winding of the transformer, are inserted autotransformer, additional capacitors and diodes, moreover, auto-.

of the transformer is connected to the first input terminal of the inverter, and the extreme leads to the second input terminal through the blue keys, the throttle winding and the primary winding of the transformer are divided into two sections, the first throttle section connected to the common point of the primary power switch and winding autotransformer, first transformer winding section, main capacitor, second transformer winding section and second throttle winding section connected to the common connection point of the second power switch and winding av of the transformer, form a series circuit in which the said winding sections are connected according to, the first additional capacitor is connected between the control electrode of the first power switch and the common connection point of the main capacitor and the second section of the primary winding of the transformer, the second additional capacitor is connected between the control electrode of the second power switch key and common point of connection of the main capacitor and the first section of the primary winding of the transformer, input circuits of power switches shuntirova our additional diodes.

In the first embodiment, the control unit contains two commuting diodes and transistors, the first commutation diode is connected between the control and power electrodes of the first and second power switches, respectively, and the second commutation diode is connected between the control and power electrodes of the second and first power switches, respectively the switching transistors shunt the input circuits of the power switches, the bases of these transistors are combined and connected to the control terminal of the block.

In the second variant, the control unit contains an inverter status sensor, the inputs associated with the power electrodes of the power switches, and the output with the input of the switch and the first input of the adjustable delay device, the second input of which is connected with the control input of the unit, and the output with the combined bases switching transistors that shunt the input circuits of the power switches, the first and second outputs of the switch are connected to the control electrodes of the first and second power switches, respectively.

FIG. 1 shows the proposed two-stroke inverter with the first embodiment of the control unit; in fig. 2 - the second embodiment of the block. management

In the device (FIG. 1), a common point of the windings 2 and 3 of the autotransformer 4 is connected to its first input terminal I. The end of the first half winding 2 is directly connected to the first electrode of the output circuit of the first power switch 5, and the circuit is indicated by the first return diode 6. The beginning of the second half winding 3 is directly connected to the first electrode of the output circuit of the second power switch 7, and the indicated circuit is shunted by the second return diode 8. The input circuits of the power switches 5 and 7 are shunted by the first and second additional diodes 9 10.

In each of the power switches 5 and 7, the common electrode for the input and output circuits is directly connected to the second input terminal of the device II.

Winding throttle 12 and the primary winding of the transformer 13 is made in two sections. The first section 14 of the windings of the throttles 12, the first section 15 of the primary windings of the transformer 13, the main capacitor 16, the second section 17 of the primary windings of the transformer 13 and the second section 18 of the windings of the throttles 12 form a series circuit in which the above mentioned sections of the windings are connected and the series the circuit is connected between the power electrodes of the switches 5 and 7. Between the first output of the capacitor 16 and the control electrode of the first power switch 5 is connected the first additional capacitor 19. Between the second output

5, the capacitor 16 and the control electrode of the second power switch 7 include a second additional capacitor 20.

The control electrodes of the power switches 5 and 7 are connected to the first and second output terminals 21 li 22 of the block 23

0 control The first and second input terminals 24 and 25 of the control unit 23 are directly connected to the first electrodes of the output circuit of the power switches 5 and 7. The terminal 26 of the control unit 23, common to the input and output circuits, is directly connected to the second input terminal 11 of the push-pull inverter.

In control unit 23, between the first output terminal 21 and the second input

terminal 25 includes the first switching diode 27, and between the second terminal output terminal 22 and the first input terminal 24 is connected the second switching diode 28. Between terminals 21 and 26 the first switching transistor 29 is connected, and between

terminals 22 and 26, the second switching transistor 30. The control electrodes of the transistors 29 and 30 are connected to the control terminal 31 of the control unit 23 via resistors.

Claims (2)

In the control unit (Fig. 2), the input terminals 24 and 25 are the inputs of the state sensor 32 of a two-stroke inverter power section. The output of this sensor is connected to the pulse input of the adjustable delay device 33 and the input of the switch 34. The output of the adjustable delay device 33 is connected via resistors to the control electrodes of the switching transistors 35 and 36, the output circuits of which are connected between the output terminals 21 and 22 and the terminal 26, common to the output and input circuits of the control unit 23. The control (analog) input of the device 33 of the adjustable delay is connected to the control clip 31. The principle of operation of the proposed push-pull inverter is considered on the example of the circuit (Fig. 1). When unlocking the power switch 5, for example, the bias current set through a resistor (Fig. 1, dotted line) between the beginning of the winding 3 and the end of the winding 2 of the autotransformer 4, a voltage drop occurs, which causes a charge of the capacitor 16 and, consequently, an increase in the potential of the first output .this capacitor and lowering the potential of the second output. At the same time, positive and negative input currents are transmitted through the capacitor 19 and 20 to the input circuits of the power switches 5 and 7, respectively, which are proportional to the charging current of the capacitor 16. The charging current of the capacitor 16 is sinusoidal due to the selection of the appropriate quality factor of the circuit formed by this capacitor and choke 12. The current of the input circuit of the key 5 varies synchronously and in phase with the current of the power circuit, which is ensured by an appropriate choice of the ratio of the capacitors 16 and 19. This ensures proportional current mode control. The flow of an oscillating LC circuit formed by the winding of the throttles 12 and the capacitor 16 through connected in series according to section 15 and 17 of the primary winding of the transformer 13 causes the transfer of energy through a rectifier and a capacitive filter (not shown) to the load. Through the half cycle of the oscillation process, the direction of the current in the circuit is reversed. In this case, the oscillating circuit current begins to flow through the return diode 6, and the voltage on the power switch 5 is inverted. The voltage inversion on this key by the control unit 23 is perceived as a signal of a change in the state of the inverter power part, i.e., a transition from the stage of energy storage in the oscillating circuit to the stage of its return. When moving to the energy recovery stage, the control unit prohibits the conductive state of the power switches. This is accomplished using a switching diode 28, which is unlocked and prevents the transfer current through the capacitor 20 to the input circuit of the power switch 7, while energy is removed from the circuit, and a current flowing through the return diode 6 provides voltage inversion on the power switch 5. During the energy output, the direction of the current of the capacitor 19 corresponds to the maintenance of the locked state of the key 5. After the energy has been removed from the oscillating circuit, the return diode 6 is locked and the switching diode is locked accordingly 28 in control unit 23. During the time of energy transfer to the circuit through the power switch 5 and then outputting it through the return diode 6, energy accumulates in the autotransformer 4, because the polarity of the voltage on the windings 2 and 3 is unchanged. When the stored energy is removed from the autotransformer 4, the unlocking current is set through the capacitor 20 in the input circuit of the power switch 7 and the locking current in the input circuit of the power switch 5, due to the flow of the current of the winding 2 and 3 through the capacitor 16. By virtue of this, the locking of the switching diode 28 causes the switch of the power switch 7 to the conduction state and then the processes are repeated. Thus, in a two-stroke inverter, an autogeneration mode arises, during which energy is transferred to the load on the secondary side, and the inverter acts as a source of bell-shaped current pulses with respect to the loads. The supply of a control pulse to the input terminal 31 allows switching the switching transistors 29 and 30 to a high conductivity state and to ensure the generation failure by pushing the input circuits of the power controlled switches 5 and 7. The time variation of the supply of control pulses and their duration is provided regulation of the output power of the device. In the control unit 23 (Fig. 2), when the return diode 6 is unlocked and the transition from the energy storage mode to the recoil mode, the sensor 32 of the state of the power unit of the push-pull inverter generates a pulse signal that switches the switch 34 to a new state ("1 output, connected with the control electrode of the power switch 7). At the same time, an adjustable delay device is triggered, which generates a signal that switches commuting transistors 35 and 36 into a conducting state. When the delay ends, the switching transistors are switched to the locked state, and the signal "1 at the second output of switch 34 causes unlocking of the second power supply" control key 7. After this, the already described processes of energy accumulation and transfer occur. By varying the delay value with an analog signal through control clamp 31, the output power is regulated. Thus, the proposed device is simpler, since the two power switches are electrically combined across the control circuit, which makes it possible to free the control transformers and reduce control losses, as well as more economically, since the power control switches of the transistor type are set to the mode of proportional-current control, and more reliably than the known ones, since the circuit automatically excludes the mode of simultaneous unlocking of power switches, since the same control current is unlocking Yush, named for one power controlled key and locking for another. Claim 1. A two-stroke inverter containing first and second power switches shunted by return diodes, a control unit connected to the control electrodes of the power switches, a transformer whose primary winding, the drossel winding and the main capacitor are connected in series, the rectifier to the capacitive filter connected to the secondary winding of the transformer, characterized in that, in order to simplify, increase the efficiency and reliability in operation, an autotransformer, additional capacitors and diodes, What is the retraction from the midpoint of the winding of the autotransformer connected to the first input terminal of the inverter, and the extreme leads to the second terminal through the power keys, the throttle winding and the primary winding of the transformer are divided into two sections, while the first section of the throttle connected to the common connection point of the first power key and autotransformer windings, first transformer winding section, - main capacitor, second transformer winding section and second throttle winding section, connected to the common connection point of the second The sludge key and the autotransformer winding form a series circuit in which the said winding sections are connected according to, the first additional capacitor is connected between the control electrode of the first power switch and the common connection point of the main capacitor and the second section of the transformer primary winding the electrode of the second power switch and the common point of connection of the main capacitor and the first section of the primary winding of the transformer, the input circuits and power switches shunted by additional diodes. 2. The inverter according to claim 1, characterized in that, in order to control the output power, the control unit comprises two switching diodes and transistors, the first switching diode being connected between the control and power electrodes of the first and second power switches, respectively, and the second switching diode connected between the control and power electrodes, respectively, of the second and first power switches, and the switching transistors bypass the input circuits of the power switches, the bases of the transistors are combined and connected to the control block clamp. 3. The inverter according to claim 1, characterized in that the control unit comprises an inverter status sensor connected to the power electrodes of the power switches and the output to the switch input and the first input of the adjustable delay device, the second input of which is connected to the control the input of the block, and the output with the combined bases of the switching transistors that shunt the input circuits of the power switches, the first and second outputs of the switch are connected to the control electrodes of the respective first and second power switches. Sources of information taken into account in the examination 1. Moin V. S., Laptev N. N. Stabilized transistor converters. M., “Energie, 1972, p. 131, 193, fig. 5-10 “a, 6-9. 2. US patent number 3953779, cl. H 02 M 3/315, 1976. / O) I cf, // ABOUT- // L / y    J fff J / yy from g Ji7 Fig. /