SU1003293A1 - Bridge converter control device - Google Patents

Description

(5) DEVICE TO MANAGE THE BRIDGE

one

The invention relates to electrical engineering and can be used in the construction of devices for pulse-phase control of bridge valve converters.

A device for pulsed-phase control of a valve converter is known, comprising a synchronizing device and a driver, the sawtooth voltage lJ.

The disadvantage is that such a device has poor noise immunity and a large asymmetry of the control angles of the mutually similar gates of each input phase of the converter.

Closest to the present invention is a device for controlling a thyristor rectifier containing an input transformer, from the secondary windings of which is connected by a single terminal through a diode in a non-conductive state to the corresponding cell of the ring scaling circuit.

The output is at the input of the phase-voltage source, the output of which is connected through the phase-shifting element to the start input of the ring recalculation cxeMfcj L2j.

The disadvantage of this device is poor noise immunity due to the fact that synchronization with the mains voltage occurs at the moments of trigger switching, which

10, in turn, correspond to the formation times of the thyristor control pulses of the converter and are determined by the triggering level of the threshold element and the sum of the 15 times the voltage of the phase-generating voltage source and the voltage of the secondary transformer. The magnitude of the voltage of the secondary winding of a transformer can be significantly changed with network distortions.

These distortions are especially pronounced when several converting devices from

a commensurate power source, KOI-and switching processes of one converter device can cause short-circuiting of the mains voltage and have a negative effect on the operation of control systems of other converters. The angle of commutation reaches its highest value at small angles of control relative to the moments of natural commutation and the smallest at the instants of the transition of the network Voltage through zero. When switching the trigger device in synchronization with the moments of transition of the mains voltage through zero, the device will have greater noise immunity. The purpose of the invention is to improve the noise immunity of the device and the symmetry of the control pulses of the thyristors of the converter. The goal is achieved by the fact that the device for controlling the bridge converter is equipped with a trigger element and a trigger pulse generation unit, the inputs of the trigger element are connected to the transformer windings, and the outputs are connected to a trigger pulse generation unit whose output is connected to the phase shifter. In addition, the trigger pulse generation unit is made in the form of two pulse extenders and a two-input logic element AND whose inputs are connected to the outputs of the pulse extenders, the inputs of the pulse extenders are the inputs of the trigger pulse generation unit, and the output of the two-input element I is its output. FIG. 1 shows a block diagram of the proposed device; in fig. 2 is a signal shaping diagram. The device for pulse-phase control of a bridge converter (Fig. 1) contains an input trans, a formatter 1, having two phase-phase input windings 2 and 3 for each phase. Next, the channel of each phase includes a trigger element, a triggering driver 5, a phase-shifting element 6 and Common for all phases, the source of 7 phase-generating voltage for the voltage, shaper 5 trigger pulses consists of a two-input logic element AND 8 and two extension cords 9 and 10 pulses.

Device. works as follows.

Claims (2)

The trigger element k changes its state (Fig. 2b and c) only when switching to positive voltage values (Fig. 2a) at one of its inputs connected to the windings 2 and 3 of the input transformer, due to this, increasing the noise of the device stability. Shorting or distortion of the mains voltage at the moment of pulse formation on one HO4 from the trigger inputs, for example FIG. 2 a (f) and figure 2 b, does not affect the state of the trigger, and switching occurs only when a positive person appears at the second entrance The potential from the other winding of the input transformer. The output pulses from the trigger element 4, synchronous with the positive and negative half-waves of the supply voltage, are extended by means of the pulse extenders E and 10 (Fig. 2 g and d) for the duration necessary to recharge the integrating phase-shifting capacitor element 6 and then fed to a logic circuit AND 8 of coincidence, the output of which produces pulses that trigger the phase shifter (Fig. 2 e). In the phase-shifting element 6, depending on the magnitude of the voltage of the source 7 of the phase-generating voltage, the pulses are shifted (Fig. 2e) by the angle of adjustment o1 (Fig. 2 g). Since synchronization with; If the network is produced at the moments of transition of the mains voltage through zero, and the pulse shift by the angle oi for one phase takes place in one channel of the device, this increases the noise immunity and accuracy of control pulse generation in comparison with the basic device. The application of the proposed device allows, due to the symmetry of the control pulses, to improve the quality of the output voltage, its symmetry in the output phases of the thyristor converter. Claim 1. Device for controlling a bridge converter, comprising an input transformer and in series connected source fazozadaimtsego voltage and the phase-shifting element, characterized in that, in order to increase noise immunity and control pulse symmetry tirystornymi transducers, angles is provided with a trigger element and a starting pulse generating unit, wherein the input trigger element connected to the windings of the transformer, and the outputs are connected to BUYUK forming trigger pulses, the output of the Tojporo is connected to the phase-shifting element. 2. A device according to claim 1, wherein the unit for forming a trigger pulse is made in the form of two pulse extenders and a two-input logic element. The VI, whose inputs are connected to the outputs of the pulse extensions, the inputs of the pulse extenders are the inputs of the trigger pulse shaping unit, and the output of the two-input logic element I is its output. I Sources of information taken into account in the examination one  1. The author of the USSR No. 598209, cl. Н02 Р 13/16, 1978. 2. USSR author's testimony No. 31236, cl. Н02 Р 13/16, 1971. rH; , L ./