A regulator circuit for star point side of three-phase AC load

Abstract

The invention discloses a star point side regulating circuit used for a three-phase alternating current load, and is used for regulating the current of a three-phase load circuit. The regulating circuit comprises three electric signal sampling circuits, a control circuit and three trigger drive circuits, wherein the three electric signal sampling circuits are used for being connected with the starpoint side of the three-phase load circuit so as to obtain a standard electric signal on the three-phase load circuit; the control circuit is connected with the three electric signal sampling circuits respectively, and is used for outputting three trigger pulse signals according to the standard electric signal on the three-phase load circuit; one end of each of the three trigger drive circuits isconnected with the control circuit respectively, the other ends of the three trigger drive circuits are connected with the three electric signal sampling circuits respectively, and the control circuit is used for controlling the trigger drive circuits to regulate current on the corresponding load circuit according to the trigger pulse signals output by the electric signal sampling circuit. The trigger drive circuits are connected to the star point side of the load circuit so as to regulate the current of the load circuit, so that the impact failure of power grid harmonic waves in working condition on the trigger drive circuits is reduced.

Description

technical field [0001] The invention relates to the field of load current regulation, in particular to a regulation circuit for the star point side of a three-phase alternating current load. Background technique [0002] With the development of industry, power system accidents caused by harmonics in the power system are becoming more and more serious. Obviously, related industrial load tests are more and more widely used, especially for the starting of high-power motors. At present, three-phase high-voltage AC high-power loads The power regulation method of this class often adopts the method of dividing each phase load circuit into multiple circuits, using multiple contactors (vacuum contactors for high voltage) to work in parallel, and performing switching control according to the required load power. Disconnecting and pulling in to switch the load, then pulling in multiple contactors requires stepwise accumulation to achieve the required load power; secondly, the high-powe...

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Problems solved by technology

[0002] With the development of industry, power system accidents caused by harmonics in the power system are becoming more and more serious. Obviously, related industrial load tests are more and more widely used, especially for the starting of high-power motors. At present, three-phase high-voltage AC high-power loads The power regulation method of this class often adopts the method of dividing each phase load circuit into multiple circuits, using multiple contactors (vacuum contactors for high voltage) to work in parallel, and performing switching control according to the required load power. Disconnecting and pulling in to switch the load, then pulling in multiple contactors requires stepwise accumulation to achieve the required load power; secondly, the high-power motor starting scheme generally connects the control regulator (thyristor) in series with the power grid and the load Between the motors, the thyristors in this connection mode are extremely vulnerable to damage caused by grid harmonics or the back electromotive force formed by the grid and the motor.

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