Transient Performance Analysis of A Six-Phase Pole Change Induction Motor for Electric Vehicles.

Abstract

We have already proposed a six-phase pole change induction motor (six-phase PCIM) for electric vehicles (EV), and have been making clear about its operation principle and steady state characteristics. The six-phase PCIM further expands the constant power operation range using the pole change technique without mechanical contactors, therefore it possesses the superb characteristics to miniaturize the EV's driving systems.This paper proposes a new analyzing method for the six-phase PCIM in order to derive the basic equations which can be utilized to analyze the transient phenomena caused by pole change and to create the control methods. First, a “six-phase tensor-transformed rotational d-q axis” (provisional name) will be defined, and its physical meanings will be made clear. By using this axis, the voltage and torque equations which can uniformly deal with the steady state and the transient state will be derived.Next, comparative examinations between the measured results and the simulated results regarding the voltage, current and torque characteristics on the steady state and the transient state at the pole change operation and the both poles dual operation will be achieved. Through these examinations, the propriety of this theory and its effectiveness in the further detail performance analysis and the application to the control method for the six-phase PCIM will be discussed.