CONTROL TECHNIQUES FOR IMPROVED HIGH-SPEED PERFORMANCE OF INTERIOR PM SYNCHRONOUS MOTOR-DRIVES

The interior permanent magnet (IPM) synchronous motor has several desirable features for high-performance adjustable-speed operation. This paper describes two control techniques to enhance the performance of the IPM drive over an extended speed range. The first technique is a feedforward compensation algorithm improving the performance of current regulators operating in the stationary reference frame. Speed-dependent back EMF and inductive voltage drops are compensated so that steady-state current errors are nulled at all speeds until current regulator saturation limits are encountered. The second technique is a flux-weakening control algorithm that uses stator current components to prevent premature current regulator saturation, thereby improving the machine's torque production capabilities at high speeds. Both new algorithms require no additional feedback signals from the motor beyond those already used in the pre-existing controls, and they are relatively insensitive to variations in the machine parameters, despite their feedforward characteristics.