Decoupling Vector Control of Single Phase Induction Motor Drives

By the advent of power electronic and microelectronic devices and circuits, together with their steadily cost reduction, single phase induction motors (SPIMs) increasingly are considered as variable speed drives in recent years. This provides improved performances and energy efficiency in traditional applications and opens the door for new applications. Vector control proved to be practical and effective in SPIM drives. However, winding asymmetry in SPIMs causes extra coupling between two stator windings and results in unbalanced machine operation and high current and torque pulsations. In this paper an indirect vector control system is proposed for SPIMs including a rather simple and effective decoupling scheme. This is achieved by introducing two new decoupling signals to the system in addition to the decoupling signals similar to ones used in three phase induction motor drives. The proposed decoupling vector control system is applied to a 0.5 hp commercial SPIM and its performance is evaluated by extensive simulation. It is shown that the proposed decoupling scheme substantially improves the motor performance by providing balanced operation and smooth currents and torque