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DC-Excited vernier reluctance machine (DC-VRM) using a 12-slot/10-pole-pair design, exhibits the advantages of small torque ripple and low cogging torque due to the inherent commentary characteristic. However, the inherent saliency is canceled out by a 12/10 pole combination of machine design driven by a traditional three-phase inverter. As a result, the sensorless operation in zero/low-speed regions becomes difficult because the position estimation methods using self-inductance detection cannot be applied. To tackle this problem, we first analyzed the saliency annihilation phenomenon through Fourier analysis that the odd-order harmonics in self-inductance are canceled. Moreover, reconstructing saliency method is proposed by splitting a phase winding into two sub-phase coils and using parallel H-bridge converters to supply sub-phase coils and achieve sensorless drive. Through this method, the saliency effect is recovered in self-inductance, thereby pulse injection sensorless drive can be applied. The constructed 12/10 DC-VRM sensorless drive shows good fault-tolerant ability and can be applied in safety-critical industry applications such as aerospace propulsion. Analysis and experiments are performed in the initial position detection, start-up and free-running stages to verify the feasibility of the proposed solution. A sector estimation accurate to 6° can be achieved. [ABSTRACT FROM AUTHOR]

Presents a study that evaluated the performance of a five-phase synchronous reluctance motor (SynRM) with two typical rotor structures through a time-stepping finite element method. SynRM system description; Basic equations of SynRM; Computation results.