This paper deals with the three-phase current reconstruction method under the low modulation index operation of three-phase three-level PWM inverters by using the single-shunt current signal measurement. The shunt is placed in a DC-link. The proposed reconstruction method is based on the combination of collinear vector injection and shifting of Space Vector Modulation (SVM) signals. The method offers a good solution for the area where the small modulation index appears. In this case, a lack of measurement time exists due to the narrow triggering pulses. This approach was studied theoretically and verified by laboratory experiments.
Keywords: current reconstruction; power electronics; single-shunt; three-level inverter; vector injection.