Design and control of system inverter-driven permanent magnet synchronous motors for high torque operation

This paper describes a current vector control method of permanent magnet synchronous motors (PM motors) for high torque operation. In this control method, the current phase angle is controlled according to load conditions in order to use the reluctance torque effectively. Several characteristics such as torque, efficiency, power capability and so on are greatly improved by this control on comparison with the conventional control method. The performance characteristics are greatly affected by the motor parameters which depend on the rotor configurations and permanent magnet geometries. The available maximum torque and power capability are also examined for the several types of PM motor considering the inverter capacity. The tendency toward magnetic saturation and demagnetization of permanent magnet are also examined.