Interference in Power system for traction drive with PMSM

The paper deals with the significant results of the research of the current harmonic spectrum in traction drive with permanent magnet synchronous motors (PMSM). The research was done in the experimental workplace with a real traction drive for wheel vehicles. The spectrums were analyzed by the specialized device on the basis of a central measuring station. The knowledge of marked subharmonic components of stator winding currents is the most significant finding of this research. The frequencies of these components are given by frequency multiples of mechanical speeds. The subharmonic components also pass to DC current at the traction inverter input site. This fact is particularly important from the viewpoint of legislative requirements to electromagnetic compatibility (EMC) of drive with railway interlocking devices.