An adaptive torque controller with MTPA for an IPMSM using model based self-correction

Abstract

In this paper a novel adaptive Maximum Torque per Ampere (MTPA) control scheme of an interior permanent magnet synchronous machine (IPMSM) is introduced. To avoid an on- or off-line numerical calculation of the reference current for the MTPA curve, a reference model of the torque which is equivalent to the IPMSM with zero d-axis current is utilized to enforce the torque of the IPMSM towards its reference value along the MTPA curve dynamically. Considering the parameter variation, an adaptive current controller with parameters and torque estimation using model reference adaptive system (MRAS) is embedded. The uncertainty within the IPMSM plant is estimated by a general voltage error to guarantee the stability of the current control loop. The parameter error of the IPMSM is estimated by a recursive least square method with a forgetting factor (RLS-FF). The stability of the proposed control scheme is proved. The simulation results demonstrate the performance of the adaptive torque controller with MTPA.