SU1365287A1 - Voltage converter - Google Patents

Abstract

The invention relates to electrical engineering. The goal is to increase reliability by gradually limiting inrush current. The converter contains an input mains rectifier 1, which is connected via the starting control key 2 to the input of the inverter 3. When the contacts of the starting switch are closed, the delay element 7 of the control unit 5 prohibits its operation. The start key 2 is closed and the voltage to the power input of the inverter 3 is not supplied. During this time, the control circuit goes to nominal mode. The control unit 5 generates one control pulse during one half-wave of the mains voltage. 2 Il.

Description

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The invention relates to electrical engineering and can be used in secondary power supply systems to convert an AC mains voltage to a constant voltage of another level or quality.

The purpose of the invention is to increase reliability by gradually limiting inrush current.

FIG. 1 shows the block diagram of the proposed converter in FIG. 2 shows voltage diagrams showing the operation of the converter.

The voltage converter (Fig. 1) contains an input network rectifier 1, the output of which is connected to the input of the inverter 3 through the starting control switch 2 and loaded onto the output driver and filter 4. The starting control switch 2 is controlled by the control unit 5, and the inverter is 3rd using the control circuit 6

The control unit 5 comprises a series-connected time delay element 7, a linear variable voltage driver 8 and a pulse generator 9 synchronized with the supply network. The output of the generator 9 is connected through the approval of the node 10 with the input of the key 2.

The Converter operates as follows.

From the time t, (the closure of the contacts of the starting switch to the time tj. (Fig. 2) the delay element 7 prohibits the operation of the ramp voltage generator 8. As a result, the start switch 2 is closed and the voltage to the power input of the inverter 3 does not flow During this time, the converter control circuit 6 goes to the nominal mode. From time t, the delay element 7 enables the generator 8 to operate the linearly varying voltage, and the pulse generator 9 through the matching device 10 opens the starting key 2. Pe A double opening pulse at the input of switch 2 appears at the time when the instantaneous value of the mains voltage is almost zero (at the end of the half-wave).

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Control block 5 generates one control impulse during a half-wave of the mains voltage. The time of occurrence of these pulses is synchronized with the network and is varied by means of a ramp voltage generator 8 so that the angle of connection of the output of the rectifier 1 to the inverter 3 varies from 180 to O during the time required for a smooth start of the converter.

Since by the time t all the transients in the control circuit 6 of the inverter 3 are already completed, the control input of the inverter receives pulses whose parameters correspond to those specified for its normal operation.

From the time t to the moment t e, the voltage at the power input of the inverter shucked by the capacitor smoothly varies from zero to the nominal value.

At time 13, the angle of connection of the network rectifier to the inverter stops and the start of the converter is considered complete. After that, the start key 2 is fully opened and does not affect the operation of the converter in the future.

Claims (1)

Invention Formula A voltage converter containing an input mains rectifier, the output of which is connected to an inverter input bypassing a capacitor through a starting control switch and a control unit with a time delay element, characterized in that, in order to increase reliability by gradually limiting the starting current, a pulse generator synchronized with the mains supply and a ramp voltage driver are inputted to the control unit, with the control circuit of the starting control key connected to the output of the generator pa pulses, the control input of which is connected via a driver linearly from yuschegos ene voltage output from the time delay element.