A Novel Full Electrical Parameters Estimation Method of Permanent Magnet Linear Synchronous Machines Considering Parameter Asymmetry

Permanent magnet linear synchronous machines (PMLSMs) have the characteristic of parameter asymmetry due to the longitudinal end effect, which introduces nonlinear, coupling, and time-varying components to the machine model and leads to additional disturbances in machine control. To obtain high precision control of PMLSM, full electrical parameters including asymmetry parameters are estimated in this article. By the erected universal model of PMLSM, it is found that the parameter asymmetry makes not only the number of estimated parameters increase but also these parameters coupled with each other. To solve the problems of rank-deficient and nonlinearity by adopting a conventional method, a novel online full electrical parameter estimation method based on high-frequency (HF) injection is proposed, which is carried out in two steps. First, the inductance and asymmetry parameters are estimated by a designed dual second-order generalized integrator based on the derived HF response of PMLSM. Second, with the obtained parameters, the resistance and flux linkage are estimated by the recursive least squares algorithm. The method's effectiveness is verified by measured parameters, and the accuracy is also compared with that of the conventional method in the prototype test platform.