Design Optimization of Bifilar Wound Switched Reluctance Motor Drives

The bifilar wound switched reluctance motor (BSRM) has transformer-like windings on the stator known as primary and secondary windings and has a unique power converter known as the bifilar converter. In this study, an optimized BSRM winding topology along with the lossless snubber for the converter is proposed. The topology investigates the uneven number of turns on the primary and secondary windings of the BSRM while taking into account the converter switch voltage spike, secondary winding current density, and demagnetization time. A lossless snubber circuit is introduced to suppress the switch voltage spike caused by the leakage inductance while preserving the efficiency of the bifilar converter. Another motivation for this research is that the bifilar converter uses fewer switches and diodes than the asymmetric half-bridge converter, which is promising to reduce costs and improve drive system efficiency. The BSRM drive system is designed and compared with the same size conventionally wound switched reluctance motor (CSRM) drive system in terms of physical structure, and efficiency using a multi-physics circuit and finite element analysis (FEA) simulation tools. The operating principle of the bifilar converter has been thoroughly examined, further, the physical setup of the BSRM drive system is tested, and the experimental results are provided.