On-line Compensation of Periodic Error in Resolver Signals for PMSM Drives

This paper proposes a novel method for online compensation of periodic position error in resolver signals based on model reference adaptive system (MRAS) and phase-locked loop (PLL) for the first time. Analytical expressions are derived to demonstrate the detrimental effects of periodic position error on the performance of PMSMs. It can be interpreted that periodic position error will lead to a distinction between stator currents fed back to current controller and real stator currents, generating current harmonics and torque ripples in PMSMs. It is proved that there exist fundamental and harmonic current vectors simultaneously due to periodic position error in resolver signals. The cross-product of fundamental and harmonic current vectors is implemented to obtain the information of position error. The principle of the novel method is elaborated, in which a reference model and an adaptive model are constructed. The reference model is based on coordinate transformation and PLL while the adaptive model is simple, containing only a coordinate transformation. Finally, the feasibility and reliability of the compensation method based on MRAS and PLL is verified by simulation and experiments.