A Novel Field and Armature Synchronous Pulse Injection Method for Sensorless Drive Control of 12/10 DC Vernier Reluctance Machine

DC-excited Vernier reluctance machine (DC-VRM) exhibits the advantages of small torque ripple and high reliability, which has good potential to be applied as an aerospace starter generator. Combined with a sensorless drive, system reliability can be further guaranteed. However, the inherent self-inductance saliency is canceled out by winding connections in 12/10 DC-VRM, thus limiting the application of the self-inductance-based sensorless drive method in such machines. By revealing the saliency annihilation effect in self-inductance and the saliency enhancement effect in mutual inductance, a novel field and armature synchronous pulse injection method is proposed based on machine mutual inductance characteristics. The key is to inject detection pulses into both field and armature windings with the same sequence and pulse width to detect the mutual inductance between them. Then, an optimized virtual inductance-based position estimation method is presented to estimate the position and strengthen the fault-tolerant ability. Moreover, the potential magnetic saturation influence on position estimation caused by superimposed detection currents is avoided with the reverse pulse injection in the field winding. Consequently, the field current density can be decreased during the detection pulse injection stage. The proposed method is easy to be implemented and verified by experimental results.