| Abstract |
A motor operating with high efficiency at variable speed essentially contributes to the energy saving of drive systems. For electric vehicles in particular, motor operation over a wide speed range is achievable through a highly efficient variable-speed drive, for instance, by changing the number of poles. To achieve high performance with pole and phase changes and obtain low-torque ripple, we proposed a motor with two or three winding groups combined with two or three inverters and had them operated under individual current control. The results of this study confirmed that the technique of both the multi inverter and multi winding allows the motor to change the number of poles and phases. In particular, the motor changing operation from 8 poles to 4 would lead to a decrease to half of the iron loss, which indicates that the motor can be expected to operate with high efficiency as it changes a high pole to a low pole at the operational region of high rotational speed. |
