Digital field oriented control of a PM synchronous actuator without current sensors

The authors describe a field oriented control system suited for PM synchronous actuators with surface mounted rare earth permanent magnets. The main feature of the system consists in the achievement of the field oriented control without current sensing in the armature windings. Moreover, the organization of the controller around two 8 bit microprocessors results in a purely digital generation of the PWM control signals for the voltage source inverter feeding the motor. Comparison with the classical solution using current sensors shows the good static and dynamic performances of the system. Experimental results confirm the theoretical results.