Active Elimination of Supply Current Harmonics in a Subway Motor-Compressor Drive

This paper considers the problem of interference of the current, consumed by motor compressor of the subway train, with the frequencies used by collision prevention system. With the incremental modification of the power converter, which feds the induction motor of the compressor, the sizes of the input filters were reduced in order to increase reliability and price. This results in significant increase of the current consumption at the frequencies of 275 and 325 Hz used by collision prevention system of Russian subways. Possible solutions to the problem were considered and a strategy for active elimination of these harmonics was proposed. It ules constant power controller for the compressor drive that decreases 25 Hz harmonic produced by the load torque; thus, 300 Hz ripple from the rectifier at the traction station do not interfere with power ripple caused by mechanical of compressor. Therefore, subharmonfcs of 275 and 375 Hz were decreased and do not affect operation of the collision prevention system The proposed control strategy is presented, it was implemented, and experimental results are provided.