Experimental Evaluation of the Online MTPA Angle Search Method Based on Flux-linkage Plane Estimation for IPMSMs

Abstract

Maximum torque per ampere (MTPA) control is a typical control method for achieving a high-efficiency operation for interior permanent magnet synchronous motors (IPMSMs). However, inductances of IPMSMs with magnetic saturation, vary depending on the current; thus, obtaining the MTPA condition is difficult. This study developed an online MTPA angle search method for IPMSMs with cross-saturation. In the proposed method, a flux-linkage plane is modeled and the model parameters are identified using the recursive least squares (RLS) method. The proposed method searches for the optimum current phase angle (MTPA angle) achieving MTPA control based on the gradient ascent method using the parameters identified for the flux-linkage plane model. This study conducted various experiments to evaluate the performance of the proposed online MTPA angle search method. The effectiveness of the method was demonstrated.