A performance study of reluctance synchronous machines fed by non-sinusoidal currents

Abstract

Reluctance synchronous Machines (RSM's) have become a viable alternative for alternating current (ac) drives since electronic drives have improved. These electronic drives make use of static switching devices to control the speed and torque of ac machines. The output waveforms of these devices contain numerous harmonics which can have harmful effects on some of the machine's performance parameters. Performance parameters of the RSM include torque, torque ripple, power, power factor and efficiency which are essential for the machine designer as well as the user. Poor efficiency of the RSM is mainly due to the copper losses of the stator windings and core losses in the stator iron. The core losses primarily consist of hysteresis- and eddy-current losses as well as additional losses which are due to domain wall rotation and pinning. Unlike the Induction Machine (JM), the RSM has no copper losses in the rotor, which reduces the operating temperature of the machine considerably. This thesis will focus on the influence non sinusoidal currents have on the performance parameters of a RSM. The machine will be subjected to ideal harmonics created by a six pulse drive which are theoretically predicted based on the operation of a six pulse drive. The machine will also be subjected to published data which are measured data for a more practical approach. These two cases will be compared to rated operating conditions.