Minimum Copper Loss Direct Torque Control of Brushless DC Motor Drive in Electric and Hybrid Electric Vehicles

A novel direct torque control (DTC) method with copper loss minimization is proposed for the brushless dc motor (BLDCM) in electric vehicle (EV) application. In order to realize high efficiency and high torque control precision at the same time, a special stator flux linkage trajectory is designed based on pseudo-dq transformation for maximum torque per ampere (MTPA) control of BLDCM. The three-phase conduction voltage vectors switch table is used to realize the flux linkage tracking control for high dynamic performance of torque control. The torque ripple caused by the non-ideality of the back EMF and the commutation in traditional two-phase conduction voltage vector based DTC method can be eliminated, which improves the torque control precision. The validity and effectiveness of the proposed DTC scheme are verified through experimental results.