BRUSHLESS MACHINES USING OPTIMAL PHASE ANGLE CONTROL

WIPO Patent Application WO2001020751

A3

A system for controlling the torque of a sinusoidally excited permanent magnet motor (12). The system includes a rotor position encoder (14), speed measuring circuit (16), controller (18), power circuit (20) and power source (22). The position and speed signals (24, 26) and a torque command signal (28) are applied to the controller (18). The torque command signal (28) is indicative of the desired motor torque. The controller (18) determines a voltage amplitude (30) required to develop the desired torque by using the position, speed, and torque command signals (24, 26, 28) and other fixed motor parameter values. The controller (18) transforms the voltage amplitude signal (30) into three phase signals by determining phase voltage command signals (Va, V