Rotor Loss Reduction Using Segmented Inverter in Surface-Mounted Permanent Magnet Drive

In this paper, the influence of different switching modulation arrangements, i.e. current waveform modulation- and phase-shift, on the resultant current waveform of an electrical machine drive consisting of a two segment inter-leaved inverter feeding a surface-mounted permanent magnet (SPM) machine with two identical sets of three phase windings is investigated. The modulation- and phase-shift have been illustrated and the influence of the different modulation and frequency indices have been studied. Furthermore, the torque, and rotor eddy currents and core losses are calculated using FEA when either modulation-shifted or phase-shifted current waveforms are generated and fed to the machine. It is found that using modulation-shift can reduce the current harmonic substantially however the inverter requires two sets of input signals. On the other hand, although the current harmonic reduction is less than that of the modulation-shift, the phase-shift layout can be employed using one set of input signals with a signal delay.