Development of a position sensorless control system on an electric vehicle driven by a permanent magnet synchronous motor

This paper presents a new position sensorless control system of an interior permanent magnet synchronous motor (IPMSM) for electric vehicles. The proposed control system is based on an injected voltage vector that is synchronized with a PWM carrier of an inverter. The pole position is estimated from the relation between the injected voltage vector and the saliency of the rotor. The first current difference vector is detected when the injected voltage vector in the estimated pole position direction is added to the motor control voltage vector. Next, the second current difference vector is detected when the injected voltage vector in the opposite direction of the estimated pole position is added to the same motor control voltage vector. Then, the pole position of the rotor with anti-saliency can be estimated from the first and second current difference vectors. This control needs neither motor parameters nor band pass filters. The anti-salient pole type IPMSM can be operated over a wide speed range including zero speed, with a quick response. Good driving of electric vehicles is realized using the proposed system.