Predictive-Pulse-Injection-Based Dual-Inverter Complementary Sensorless Drive for 12/10 DC Vernier Reluctance Machine

Abstract

A dc-excited Vernier reluctance machine (DC-VRM) using a 12-slot/10-pole-pair design exhibits the advantages of small torque ripple and a robust structure, which has good potential to be applied as an aerospace integrated starter/generator. By eliminating vulnerable position sensors, system reliability can be further improved by sensorless startup. However, driven by the traditional three-phase inverter, the phase inductance of the 12/10 DC-VRM becomes constant due to its complementary characteristic, which means the saliency effect in DC-VRM is obliterated, and thereby a sensorless operation using self-inductance detection cannot be applied. To release the machine saliency effect and further improve sensorless drive performance, a dual-inverter sensorless drive structure is introduced to reconstruct the machine saliency by using separated dual three-phase inverters. The released series inductance model with mutual inductance coupling is established through a piecewise function, and an accurate position estimation method without finite-element analysis or complex measurements is introduced. Moreover, by further analyzing the linearity of series inductance, the full-cycle inductance high-linearity range is composed of dual-inverter complementary features, and thus position estimation accuracy can be guaranteed. Through this feature, a predictive-position-based pulse injection sensorless drive method is proposed to improve acceleration performance with detection time reduction. Based on the predictive position, the detection pulses are only injected into one inverter whose corresponding phases are located at the inductance high-linearity range, thus decreasing the detection time and improving acceleration performance.