Inverter DC Link Current Spectrum Analysis for PMSM Based on Vector Control

Abstract:

The accurate analysis of the inverter DC link current is the key to the assessment of the electromagnetic interference and computation and selection of the DC link capacitance. Aiming at the mathematical expression and solving method to the inverter DC link current for PMSM based on vector control, the paper analyzed the corresponding equivalent inductances for the fundamental wave and the high order harmonics of the phase voltage. The results show that the equivalent inductances for all the harmonic waves of the salient pole PMSM are equal and constant, the equivalent inductances for the high order harmonics of non-salient PMSM are changeable with the rotator position, and the fundamental wave can be decomposed on the d-axis and q-axis by phasor synthesis and the corresponding inductances are d-axis inductance and q-axis inductance. In the theoretical computation, the high order inductances can be regarded as a constant through averaging method or the high order harmonics can be abandoned. The correctness and effects were verified through the simulation and experiment.