Torque Feedforward Control Technique for Permanent Magnet Synchronous Motors

This paper proposes a torque control method for Interior Permanent Magnet (IPM) motors operating in a wide speed range requiring high torque/power accuracy and fast dynamic response. Using the fact that the motor parameters are nonlinear and vary significantly with direct and quadrature current operating points, a new optimal operating plane is generated. This operating plane combines the PTPA (Peak Torque per Ampere) curve, current limit circle and MTPV (Maximum Torque per Volt) curve, voltage limitations and torque calculation under the nonlinear parameter variations. As a result, new feedforward tables are generated which make full use of measured motor parameters. The new torque and flux regulators built around the feedforward tables provide fast dynamic response and accurate steady state torque/power production. The proposed controller was implemented and successfully tested on a 105kW IPM motor electric drive used in a fuel cell vehicle program.