A three-phase current reconstruction technique using a single current sensor based on active vector pulse insertion

Abstract

A single dc-link current sensor to reconstruct all three inverter phase currents has been proposed for the purpose of cost reduction and sensor fault tolerance in the motor drive. A novel phase current reconstruction scheme, with the immeasurable areas reduced, has been reported in the paper to tackle the problems caused by the presence of regions in the voltage vector plane where the phase currents are not directly measured. An active vector pulse insertion method achieves this objective by applying additional active voltage vectors in the brief intervals, and guaranteeing the invariant duty cycle in three-phase leg configuration during each fundamental frequency cycle. The effectiveness of the proposed reconstruction algorithm has been verified via a permanent magnet synchronous motor drive with 500 W rated power. Simulation and experimental results are provided to confirm the attractive performance characteristics of the resulting current reconstruction and regulation using the active vector pulse insertion method.