SU1467702A1 - Variable a.c. to a.c. voltage converter for lc-circuit supply - Google Patents

Abstract

This invention relates to the field of converter technology. The purpose of the invention is to increase the power delivered to the load due to a more complete use of the energy of the storage capacitors. The capacitors of block 3 are charged through the thyristors of block 1. The synchronization pulses corresponding to a certain phase of the input voltage through block 11 of delay, the OR element 9 and the driver 10 open the thyristors of block 2, after unlocking which the energy from block 9 is transferred to the LC circuit 4. the time interval T / 4 formed by the driver 12, after the accumulative capacitor of the unit 3 is discharged, a signal from the current sensor 5 is re-delivered to the thyristors of the unit 2, thereby achieving the goal. 5 il. S cl

Description

l 10 pulses, and the second input is a connection IS-NOT 44. The output of the element IS-NOT 42 is soleno with the output of the first block 11 of the pulse delay and the input of the driver 12 of the time interval connected by the output with the second input of the second block 8 of the delay. The control DO input of the first delay unit 11 is connected to the output voltage setting unit 13 of the output voltage, and the synchronization input is connected to the output unit 14 of the sindeen with the output terminal of the counter 38, as well as the input of the AND-44 element, which other input is connected to the input 45 block 8.

FIG. 5 shows the device forming the 6 blocking pulses. It contains a rectifying diode bridge 46 connected to the input terminals 47, the output of which is connected

synchronization, the input of which is connected 45 resistor 48. Variable resistor 49

to input pins 15 for connecting the network.

FIG. 2 shows the supply voltage 16, the voltage 17 at the output of the synchronization unit 14, the voltage 18 at the output of the delay unit 11, the voltage 19 at the output of the time period generator 12, the current 20 in the LG circuit 4, the voltage 21 at the driver output 6 blocking pulses, the voltage 22 at the output of the driver 7 additional control pulses, the voltage 23 at the output of the block 8 delay, voltage 50

55

one output is connected to the negative output of the rectifying diode bridge 46, and the other to the positive power supply bus. The comparator 50 is connected to one input with a positive output of a capacitive diode bridge 46, and the other to a control terminal of a variable resistor 49, the output of comparator 50 is output 51 of the former 6.

Shaper 7 additional control pulses and shaper 12 of the time interval are made in the form of single vibrators. Block 13

AND-NO 44. The output of the item AND-NO 42 is connected to the zeroing input of the counter 38, as well as to the input of the item AND-NO 44, the other input of which is connected to the input 45 of block 8.

FIG. 5 shows the device of the driver 6 blocking pulses. It contains a rectifying diode bridge 46 connected to the input terminals 47, to the output of which is connected

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one output is connected to the negative output of the rectifying diode bridge 46, and the other to the positive power supply bus. The comparator 50 is connected to one input with a positive output of a capacitive diode bridge 46, and the other to a control terminal of a variable resistor 49, the output of comparator 50 is output 51 of the former 6.

Shaper 7 additional control pulses and shaper 12 of the time interval are made in the form of single vibrators. Block 13

phase assignment - in the form of a variable resistor. Shaper 10 pulses and block 14 synchronization can be made in the form of any lime structure. The charge thyristor unit 1, the storage capacitor unit 3 and the discharge thyristor unit 2 can be configured, for example, as shown in FIG. 1 and contain drosel de selec 52, charge thyristors 53 and 54, chokes 55 and 56, discharge thyristors 57 and 58, and capacitors 59 and 60.

The device works as follows .15

In the process of charging the storage capacitors of block 3 through the thyristors of block 1, the current in the circuit has the form of a half-wave sinusoid. When this current reaches zero, the charge thyristors 20 are locked. The storage capacitors at this time are charged to a certain voltage, depending on the angle of control of the thyristor, the supply voltage and the parameters of the charge circuit elements. Since thyristors can be considered as ideal switches, and the leakage current in storage capacitors is negligible,

the first switching, was not transferred from the storage capacitor to the electromagnet circuit. For its transmission, additional thyristor control pulses of block 2 are generated. The first control pulse arrives at the time interval generator 12, which is a one-shot, which generates a pulse equal to 1/4 of the period T of the mains supply, during which it is possible to pass through the second delay unit additional pulses for controlling the thyristors of unit 2. An impulse with a duration of T / 4 is fed to the input, 43 -block 8 delay. At the moment of the discharge of the storage capacitor to the LC circuit 4, the signal from the current sensor 5. In the form of a half-wave sinusoid enters the driver 6 blocking pulses. The impulses formed at its output are equal to the duration of the current flow in the circuit. the discharge of the storage capacitors is fed to the input of the generator 7 additional control pulses which, by the decay of the input pulses, produces pulses arriving

the charge accumulated in them can be taken to the second input 45 of the delay unit 8,

live for a considerable time. The synchronization pulses, outputted by the synchronization unit 14 and corresponding to a specific voltage phase at the input of the converter, are fed to a delay unit 11 controlled by the phase reference unit 13. The pulses from the output of block 11 are fed to the first input of the element OR 9 and then to the shaper 10 pulses to control the thyristors of block 2, after unlocking the energy accumulated in the capacitors of block 3, is transmitted as short pulses to the LC circuit 4. Chokes 55 and 56, increasing the discharge time of the capacitors of the unit 3 to the capacitor of the LC circuit 4, protects the discharge thyristors of the unit 2 from breakdown and increases the efficiency of the converter.

At the moment of equality of the voltages on the storage capacitor unit 3 and on the capacitor LC circuit 4, the thyristor unit 2 is closed. Wherein

35

40

45

50

part of the energy is equal to

From i, 2U to

Where

from the output of which, through the element OR 9 and the driver of the 10 pulses, enters the block 2 of discharge thyristors. The thyristor of unit 2 opens again and closes again at the moment of equal voltage on the storage capacitor and on the capacitor LC-circuit 4. Again an additional control pulse is generated, which with a delay arrives at the shaper 10, the thyristor opens again. The process is repeated in the time interval T-4 until the storage capacitor of the unit 3 is completely discharged.

Since the process of recharging and an auxiliary capacitor on the LC circuit. 4 passes almost instantly, then during T-4 the storage capacitor almost completely transfers its energy to the LC circuit 4.

Due to the smoothing effect of an electromagnet inductance, the magnetic field induction curve is very close to a sine wave.

C - the value of the capacity of the storage capacitors of the block 3; U ,, is the voltage on the LC circuit 4 at the time of blocking the thyristor 57 (58) of block 2 after

first switching, it was not transferred from the storage capacitor to the electromagnet circuit. For its transmission, additional thyristor control pulses of block 2 are generated. The first control pulse arrives at a time interval generator 12, which is a one-shot, which generates a pulse equal to 1/4 of the period T of the mains supply, during which it is possible to pass through the second block 8 of delay additional pulses for controlling the thyristors of unit 2. An impulse with a duration of T / 4 is fed to the input, 43 -block 8 delay. At the time of the discharge of the storage capacitor to the LC circuit 4, the signal from the current sensor 5. In the form of a half-wave sinusoid enters the driver 6 blocking pulses. The pulses formed at its output are equal to the duration of the current flow in the circuit. The size of the storage capacitors arrives at the input of the generator 7 additional control pulses, which, by decreasing the input pulses, produces pulses arriving

five

0

five

0

five

from the output of which, through the element OR 9 and the driver of the 10 pulses, enters the block 2 of discharge thyristors. The thyristor of unit 2 opens again and closes again at the time of equal voltage on the storage capacitor, capacitor and capacitor LC-circuit 4. Again an additional control pulse is formed, which with a delay arrives at the imaging unit 10, the thyristor opens again. The process is repeated in the time interval T-4 until the storage capacitor of the unit 3 is completely discharged.

Since the process of recharging the storage capacitor to the LC circuit .4 takes place almost instantaneously, during the time T-4 the storage capacitor almost completely transfers its energy to the LC circuit 4.

Due to the smoothing effect of the inductance of an electromagnet, the magnetic field induction curve is very close to a sinusoid.

Claims (1)

Invention Formula Adjustable AC to AC converter for  And P iplg and n ft t n n n rt Fia.g 7 Phie. 51 -O FIG. five