Maximum Torque Per Ampere Operation for IPMSM Based on Sliding-Mode Extremum Seeking Control

Aiming at the problem of poor robustness of model-based maximum torque per ampere (MTPA) algorithm, a sliding mode extremum search control based MTPA (SMESC-MTPA) method with d-axis current as search variables is proposed. SMESC-MTPA does not require either sinusoidal excitation signal or high-pass and low-pass filters to estimate the function gradient. Based on Lyapunov criterion, the stability of SMESC-MTPA is analyzed, and the convergence speed and control accuracy of the proposed algorithm are studied by analyzing the formation and switching process of sliding mode surface. The effectiveness of the proposed method is verified by simulation and experiment.