Single current sensor technique in the DC link of three-phase PWM-VS inverters: a review and a novel solution

A review of the existing methods to determine the output currents in a pulsewidth modulation voltage-source (PWM-VS) inverter using a single current sensor in the DC link is presented, and a novel solution is proposed. The unique arrangement of the DC link allows full protection of the inverter from short circuits and overloads. Also, a new method of sampling the DC-link current is described that produces true values of the output currents at the centers of switching intervals. Results of investigation of an experimental setup have shown that full protection of the inverter has been accomplished and the output currents can accurately be determined within the whole operating area.