Independent vector control of Induction Motor and Permanent Magnet Synchronous Motor fed a four-leg inverter

This paper proposes the system for independent drive of three-phase Induction Motor (IM) and Permanent Magnet Synchronous Motor (PMSM) fed by a four-leg inverter (4LI) with vector control method. The 4LI is a single inverter that can drive two AC motors independently. If it´s possible that the proposed system can drive IM and PMSM independently, 4LI enlarge the range of its use. The inverter consists of four legs and two capacitors connected in each leg, respectively, whereas the W phase of both motors is connected in the neutral point of two-sprit capacitors. The neutral point voltage is needed to maintain half magnitude of DC-bus voltage for stable driving two ac motors. So the compensation method restraining the drift phenomenon is shown. Next, the experimental results, driving two IMs, demonstrate the validity of the compensation method. Finally, confirm that the proposed system with vector control method and compensation method for drift phenomenon can drive IM and PMSM independently.