Development of an algorithm for controlling the power regulators in the testing station of rolling stock traction electric motors

Abstract

The article deals with the issue of energy efficiency of power regulators used at test stations for rolling stock traction electric motors. The analysis of the existing equipment showed that in thyristor converters switching gaps exist in the sinusoid curves of the supply voltage and non-sinusoidality in the current curve. The presence of these interferences is caused by the existing switching interval, resulting in an interphase short circuit of the switched phases. Besides, the existing power regulators reduce the operating voltage. The analysis of the operation of the proposed power controllers as part of the test station made it possible to develop an effective control algorithm for power semiconductor devices that directly transfer electrical energy from an intermediate energy storage device to traction motors. The repetition rate of voltage pulses applied to the windings of traction electric motors is chosen in such a way that the current ripple factor in the traction motors windings does not exceed 2 % without using a smoothing reactor, which is a distinctive feature of the use of controlled rectifiers, in which a smoothing reactor is used to reduce the ripple factor. The presented mathematical analysis of the power controllers of the test station proves the effectiveness of the developed algorithm for controlling power semiconductor devices. The impact on the supply network is minimized by choosing the appropriate width of the power semiconductor devices control pulses at each stage of the traction electric motors operation. The proposed control algorithm makes it possible not to load the supply network with additional currents providing high electromagnetic compatibility of the test station with the supply network over the entire range of power regulation.