Decoupling Control of Single-Stage Multiport Inverter-Fed Motor Drives Using Zero-Sequence Voltage Injection

The single-stage multiport inverter (SSMPI)-fed motor drives enable direct connection from the dc-side energy sources to the ac motor without utilizing any dc/dc converters, which feature high power density and high efficiency of the overall system. However, the output power of each source is highly coupled with the motor control in this topology, which provides poor flexibility of power control. To address this problem, a decoupling control strategy is proposed in this paper. First, an asymmetrical carrier-based modulation strategy is adopted to ensure the high performance of the motor control by fully considering the voltage variation of sources. Then, injecting different values of the zero-sequence voltage adds a degree of freedom for controlling the output power of sources. With the proposed method, the flexible power control is realized without affecting the performance of the motor control. Finally, the effectiveness of the proposed control scheme is verified through experiments on a permanent magnet synchronous motor (PMSM)-based laboratory prototype.