Bipolar operation of fully-pitched winding switched reluctance drives

Doubly salient switched reluctance (SR) machines usually have single-tooth windings supplied from unipolar power converters. For bipolar operation with independent phase current control, four active devices per phase are required. However, for a three-phase machine connected in star configuration, bipolar phase currents can be supplied from a standard six switch bridge circuit. An experimental fully-pitched winding SR machine has been produced by rewinding a conventional single-tooth winding SR machine that was rated at 7.5 kW, 1500 RPM. The drive electronics comprises of an IGBT inverter switching at 10 kHz, and a microprocessor based controller. The results presented in this paper were obtained from an experimental drive operating at low speed, with the phases connected separately, or in star configuration.