Sliding-Mode Observer for IPMSM Sensorless Control by MTPA Control Strategy

Abstract: This paper presents a nonlinear sliding mode control (SMC) scheme for interior permanent magnet synchronous motors (IPMSMs).The proposed SMC is able to reduce the settling time without an overshoot by giving a low damping ratio at the initial time and a high damping ratio as the output reaches the desired setpoint. At the same time, it enables a fast convergence in finite time. To improve the efficiency of a system in the constant torque region, the control system incorporates the maximum torque per ampere (MTPA) algorithm. The stability of the nonlinear sliding surface is guaranteed by Lyapunov stability theory. The effectiveness of the proposed nonlinear SMC scheme is verified experimentally. From these experimental results, the proposed nonlinear SMC method reveals a faster transient response, smaller steady-state speed error, and low sensitivity to system uncertainties.