Adaptive Maximum Torque per Ampere Control for IPMSM Drives With Load Varying Over Mechanical Revolution

Abstract

This paper proposes an adaptive maximum torque per ampere (MTPA) control algorithm for interior permanent magnet synchronous motor (IPMSM) drives. This algorithm is insensitive to motor parameters variation due to operating conditions that is important for systems, which prioritizes reliability and efficiency. The proposed algorithm is designed to improve conventional control schemes, where the output of the speed controller is the commanded quadrature current and direct current is calculated using an MTPA equation. However, in distinction from the conventional MTPA approach, the proposed algorithm does not use any motor parameters. It implements a seeking technique and continuously varies the stator current phase angle while trying to minimize the magnitude of the current. The main contribution of this paper is the development of the method to overcome the main disadvantage of seeking algorithms – the necessity of stable disturbances at the consecutive measurement intervals. This paper adopts the seeking technique for the operation with the load torque varying over mechanical revolution, which is typical for many applications such as compressors, washing machines, robots, mechanical manipulators, servodrives, etc., The feasibility of the proposed algorithm is proven with experimental results shown and described in the corresponding section.