A Novel Direct Torque Control Method of PM Synchronous Motors

Direct Torque Control (DTC) technique is a fast, simple, and robust control method, which is not dependent to the parameters of the motor and environmental variations. Its drawbacks are variable switching frequency and high torque ripple. In this paper a new control technique is presented which provides a constant switching frequency and reduces the torque ripple comparing with conventional DTC methods. The fundamental equations of permanent magnet synchronous motors and condensational DTC method are explained. The proposed control technique is introduced and its limitations are discussed. A sensorless technique for rotor position detection and implementation of the new control method is also discussed. Experimental results of the proposed system are provided to show its viability and advantages over the conventional method.