Current Control for AC Motor Drives Using a Single DC-Link Current Sensor and Measurement Voltage Vectors

A new algorithm using a single dc-link current sensor to reconstruct all three inverter phase currents has been proposed that overcomes problems caused by the presence of regions in the voltage vector plane where the phase currents are not conveniently measurable. The measurement vector insertion method (MVIM) achieves this objective by applying additional active voltage vectors for brief intervals only when needed during each fundamental frequency cycle. This paper addresses techniques for incorporating the MVIM algorithm into a closed-loop current regulator designed to provide high-quality current control using a single dc-link current sensor. Virtual active resistance state feedback is introduced into the synchronous-frame current regulator in order to improve the controller's ability to reject disturbances caused by the MVIM measurement vectors. Experimental results are provided to confirm the attractive performance characteristics of the resulting current reconstruction and regulation using the MVIM algorithm