A Complementary Carrier based PWM Strategy for Average Current Sampling of Three-Phase Inverter Using Single Current Sensor

This paper proposes a complementary carrierbased pulse width modulation (PWM) strategy for the average current sampling of three-phase inverter using single current sensor (SCS) in dc-link. Conventional three-phase current reconstruction method for a three-phase inverter using SCS reconstructs the three-phase currents by measuring the two-phase currents corresponding to the two active voltage vectors. However, the current measured by SCS is not the average current. In addition, there is a current reconstruction dead zone (CRDZ) near the boundary of each sector. The proposed PWM strategy outputs the voltage of the inverter using two carriers that are inverted in phase with each other. This strategy compares the inverted carrier with the voltage references of one or two phases and compares the remaining phase voltage references with the noninverted carrier. This allows us to measure the average current and significantly reduces the CRDZ to the corners of the space vector hexagon. The validity of the proposed strategy is verified by simulation results.