SU1636971A1 - Device for controlling push-pull transistor inverters - Google Patents

Abstract

This invention relates to electrical engineering and can be used in secondary power supply sources. The purpose of the invention is to expand the functionality by ensuring the stabilization of the average value of the voltage across the load when the supply voltage changes. The goal is achieved due to the fact that the frequency of

Description

The invention relates to electrical engineering and can be used in the sources of secondary power supply systems of radio engineering, automation and computer technology.

The aim of the invention is to enhance the functionality by stabilizing the average value of the voltage across the load as the supply voltage changes.

1 shows a diagram of the device; figure 2 - characteristics of the input - the output of the Comparators; Fig. 3 shows voltage diagrams for the operation of the device.

The device for controlling an inverter made in the form of power transistors 1 and 2 (Fig. 1) and output transformer 3 with primary windings 4 and 5 connected according to the middle point circuit and secondary winding 6 contains a sensor 7 of the magnetic core the output transformer 3 and the control unit 8; In the control unit 8, the winding 9 of the sensor 7 is connected via bridge rectifier 10 to the inputs of comparators 11 and 12, the output of comparator 11 is connected to the input Zi of the pulse selector 13 in duration, the output Q of which together with the output of comparator 12are respectively the inputs Xi and Xa of the digital automat 14, the outputs YI and Y2 of which are connected via power amplifiers 15 and 16 to the power transistors 1 and 2. The output of the comparator 12 is connected to the input of the element HE 17 and the first input of the element 18 and the output of the selector 13 pulse duration - to the input element 19 and the first input element And 20, and the output element 19 is connected to the first input element And 21, and the output element NOT 17 - to the first input element And 22, the second input is connected to the first inputs of elements And 23 and 24, with the second input element And 21, with the input element is NOT 25 and with the output of the element OR 26, the inputs of which are connected to the outputs of the elements And 21, 20 and 24, and the second input of the element And 24 is connected to the second input of the element And 20, with the first input of the element

Both 27 and with the output of the element NOT 28. whose input is connected to the second inputs of the elements AND 23 and 18 and to the output of the element OR 29, the inputs of which are connected to the outputs of the elements And 18, 22 and 23, and the output of the element And 23 being simultaneously the output YI of the digital circuit breaker 14, through the power amplifier 15 is connected to the base of the power transistor 1, and the base of the power transistor 2 is connected to the output of the power amplifier, to the input of which is connected the output of element 27, which is the output of Y2 digital automatic circuit 14, the second input of element 27 and connected to the output of the element HE 25, than the pulse generator 30 and the output is connected to an additional control input 13 of the selector Z2 pulse duration.

The device works as follows.

The switching voltages of the comparators 11 and 12 are selected in accordance with the characteristics shown in Fig. 2. Pulse selector 13 has a duration Zi input from comparator 11, additional control input22 from a pulse generator 30, output Q connected to input Xi of a digital automaton 14. Pulse selector 13 passes a signal Zi 0 from the comparator output to input Xi of a digital automat 14 only in the case of the appearance at the control input Z2 of a logical one. The operation of the selector 13 pulses in duration occurs in accordance with Table 1. The table

Signals from the comparator 11 about the presence of current in the windings 4-6 come to the input Zi. those. if Zi 0, then the currents in the windings are absent, and the additional control input Z2 contains signals from the generator of 30 pulses. The latter starts simultaneously.

supplying power to control unit 8 and generating short pulses of positive polarity. The pulse period of the generator 30 is equal to the saturation time of the core of the power transformer 3 when 4 or 5 minimum supply voltage Un min at the input terminals of the inverter is applied to the half-winding.

Digital automat 14 has input Xi, which is output Q of selector 13 pulses in duration, input X2 from comparator 12, X2 1, means the operating point on the magnetization reversal curve of the core of output transformer 3 approached saturation zone, output YI of control of transistor 1 and output of control Y2 transistor 2. If the signals at the output of YI or Ug are equal to logical 1, the corresponding transistor 1 or 2 is open, if to the logical O - the corresponding transistor is closed. The operation of the digital automaton 14 can be described using the table, 2 states. When power is applied to the control unit 8, the digital automaton 14 is set to state 1 (Table 2), when logical 1 is present at the output of the YI element And 23, and logical O is present at the output of the Ya element And 27. Table 2

Element 23 signal is amplified by power amplifier 15, transistor 1 opens, and the inverter starts working. When power is removed from control unit 8, transistors 1 and 2 are locked and the inverter turns off.

Voltage Emp from winding 9 of sensor 7 is proportional to the derivative of the total current with respect to time. At the output of the rectifier 10, an EMP voltage is formed.

The operation of the device is taken from the voltage diagrams (Fig. 3). Let at the time tt at the voltage at the input terminals of the inverter Un Un min turn on transistor 1 (the digital automaton is in state 1, table 2, and input 2.2 receives a pulse from the pulse generator 30, table 1) and through winding 5 begins leak current. The signal from the winding 9 of the sensor 7 is rectified by the bridge rectifier 10 and in positive polarity is fed to the outputs of the comparators 11 and 12. After the flow of current through the primary winding 5 begins, the signal from the winding 9

sensor 7 increases slightly, which causes the comparator 11 to switch from a logical O state to a logical 1 state. As current flows through the winding 5

0, the core of the output transformer 3 is saturated, the signal from sensor 7 rises sharply, which causes the comparator 12 to switch from the logical state O to the logical state 1. This corresponds to the time t2 (FIG. 3). Digital automat 14 is then set to state 3 (Table 2) when YI and Y2 are equal to logical O, i.e. The bases of transistors 1 and 2 receive the blocking signals from power amplifiers 15 and 16. Transistor 1 is closed. When transistor 1 is closed, the signal from winding 9 of sensor 7 is close to zero, comparator 11 is switched to the state corresponding to the presence of a logic

5 O at the input Zi of the selector 13 pulses in duration, however, logical 1 is still present at its output. At the instant of time r3, from the generator of 30 pulses to the additional input Z2 comes

0 a pulse of positive polarity, which causes the output at the output Q of the selector 13 to have a pulse of logical duration O, and therefore a logical 0 is now present at the input Xi of the digital auto mate 14. The digital automat 14 (in accordance with Table 2) switches to 4, when YI is equal to O, and Y2 is equal to 1. At the base of transistor 2, through the power amplifier 16, there is a triggering signal.

0 Next, similar processes are repeated with the transistor 2. Suppose that at time t4 the supply voltage increases to Un Un mm. Now the saturation time of the core of the output transformer 3 is reduced,

5, respectively, 2 times, since it is inversely proportional to the voltage applied to the transformer winding. 8 moment of time ts transistor 1 turns on. Digital automat 14 - in state 1. In

0 moment of time te, the output transformer 3 is saturated and transistor 1 is turned off. Transistor 2 is turned on at time t after the pulse arrives from pulse generator 30 to the additional input of selector 13 pulses in duration, which causes the appearance at input Xi of digital automat 14 logical O and switching digital automat 14 into state 4 when YI O , a Ya 1. Further processes proceed similarly. So about: once, the average load voltage at

The change in power at the input terminals of the inverter remains unchanged, since the duration of the voltage pulse across the load varies inversely with the amplitude of the voltage pulse UH across the load (Fig. 3).

Claims (1)

The formula of the grid image A device for controlling a push-pull transistor inverter containing a magnetic sensor of the core of an inverter output transformer, the output of which is connected to the inputs of the first and second comparators via a bridge rectifier, the output of the first comparator is connected to the first input of the digital automat made in the form of seven elements AND, four elements NOT and two elements OR, and the inputs of the first and second elements are NOT used as the first and second inputs of the digital automat, respectively and connected to the first inputs of the first and second elements And, respectively, the second input of the first element And connected to the first input of the third element AND and the output of the first element OR, the second input of the second element And connected to the first input of the fourth element And and the first input of the fifth element And, the second inputs of the third and fourth elements And are combined and connected to the output of the second element OR and the first inputs of the sixth and seventh elements AND, the second inputs of which are connected to the outputs of the first and second elements NOT respectively, output dy the first, third and sixth elements And connected to the inputs of the first element OR, the outputs of the second, fourth and seventh elements AND - with the inputs of the second element OR, the outputs of the first m of the second element OR are connected to the inputs of the third and fourth elements, respectively, the outputs of which are connected to the first and second inputs of the fifth element AND, respectively, the output of the third element It is used as the first output of the digital automat and is connected to the input of the first power amplifier, the output of which is intended to be connected to the control input of the first transistor of the inverter, for connection to the control input the second transistor of which is intended to output the second power amplifier, the input of which is connected to the output of the fifth element AND, used as the second output of the digital automaton, characterized in that, c, to expand the functionality of the device by stabilizing the average value of the voltage at voltage change. power supply, a pulse generator and a pulse selector for duration are introduced, functioning in accordance with the switching table of the form Zi o o one one Z2 about 1 about 1 Q 1 O 1 1 the BxoAZi pulse selector is connected in duration to the output of the second comparator, input Z2 to the output of the generator, pulses, and output Q to the second input digital machine. cailotar it Uiax comparator iz tjluit U