Full Electrical Parameter Identification Method for PMLSM Based on Triangular Wave Injection and Considering Current Differential Terms

Online parameter identification can enhance the control accuracy and operational robustness of permanent magnet linear synchronous motors (PMLSMs); therefore, it has been extensively researched. However, the analysis of parameter observability has rarely been addressed. This paper utilizes the local weak observability theory transforming the complex observability analysis into a concise algebraic problem. Moreover, it theoretically proves that accurate identification of all electrical parameters of PMLSM can be achieved when the differential terms of the d-q axis currents are non-zero during steady-state operation. This provides a theoretical foundation for the subsequent identification method proposed in this article. The method adopts the biased triangular wave injection approach and considers the effect of the current differential term. The three electrical parameters of resistance, inductance and flux linkage of the PMLSM can be accurately identified at different velocities and thrusts under steady state operation, and the identification error of each parameter is less than 3%.