Cooperative Control for Motor Drive System Integrated of Multiple High-Speed Motors and Magnetic gear

A novel motor drive system integrated of multiple high speed motors and magnetic gear which called as Magnetic Multiple Spur Gear (MMSG) efficiently converts the total output power of high speed motors by using MMSG in non-contact, that is effective to realize the downsizing, high power density, and high efficiency for motor systems. However, it causes the torque unbalance between multiple motors by the effects of the difference of individual motor parameters such as inductance and winding resistance, and the detection error of magnetic poles position that causes unbalanced load between motors, resulting in lower efficiency and out-of-synchronization of magnetic gear. Moreover, the simple and inexpensive control system is required for driving multiple motors. In this paper, the behavior of MMSG when torque unbalance occurs is clarified, the cooperative control for torque unbalance between multiple motors is proposed.