A New High-Frequency Voltage Injection Method for Sensorless Drive of Permanent-Magnet Synchronous Motors with Pole Saliency

This paper proposes a new sensorless vector control method for salient-pole permanent-magnet synchronous motors. In regard to rotor phase estimation, the sensorless vector control method is featured by a new high-frequency voltage injection method distinguished from the conventional ones by a unique ellipse shape of the spatially rotating, and by a new PLL method whose input is a high frequency current auto-correlated signal. The new vector control method established by two innovative technologies can have the following high-performance and attractive features: 1) it can allow 250% rated torque at standstill; 2) it can operate from zero to the rated speed under the rated motoring or regenerating load; 3) it accepts instant injection of the rated load even for zero-speed control; 4) it accommodates a load with huge moment of inertia; 5) phase estimation is very robust against inverter dead time; 6) computational load for estimating rotor phase is very small, would be the smallest among the methods with comparable performance. This paper presents the new vector control method by focusing on two innovative technologies from its principles to design rules. Usefulness of the new vector control method is verified through extensive experiments.