Virtual square-wave current injection based maximum torque per ampere control for interior permanent-magnet synchronous machines

The maximum torque per ampere (MTPA) control has been widely employed to improve the efficiency of the interior permanent magnet synchronous machine (IPMSM) drive systems. To achieve online MTPA tracking, in this work, a virtual square-wave current injection based method is proposed. Since no machine parameters and pre-tuning effort are required, the proposed method is robust against parameters and temperature variations. In addition, compared to the existing signal injection based MTPA control, the proposed method eliminate the bandpass filter, which is usually used to extract the gradient of torque with respect to the current control angle, such that the controller bandwidth will be significantly improved to meet the dynamic requirements of the IPMSM drive system for vehicle applications. The feasibility and effectiveness of proposed methods are verified by simulation studies of a high power IPMSM drive system.