Basic Principle and Maximum Torque Characteristics of A Six-Phase Pole Change Induction Motor for Electric Vehicles

In addition to basic characteristics such as a small size, light weight and easy maintenance, the electric vehicle (EV) motor is required to possess characteristics which allow for the production of a high torque at a low speed region and to realize a wide range of constant power operation at a high speed region.In an attempt to further improve the constant power operation properties of the induction motor (IM), this paper proposes a six-phase pole change IM (six-phase PCIM). The six-phase PCIM further expands the constant power operation range without increasing the volume and current of IM.To clarify the basic principle and the torque characteristics of the six-phase PCIM, first, its winding method and distribution of mmf will be examined. Next, by establishing a performance calculation method based on quasi-sinusoidal wave method, the feasibility of a highly precise performance calculation sufficient for actual use will be demonstrated. Furthermore, by clarifying the maximum torque characteristics through experiment, the feasibility of the expansion of the constant power operation range will be confirmed and its effectiveness in the EV will be discussed.