Full Electrical Parameter Estimation Method of PMLSM Considering Parameter Asymmetry Without External Excitation

The longitudinal end effect of permanent magnet linear synchronous machines (PMLSMs) induces parameter asymmetry, imparting time-varying and nonlinear characteristics to the machine model. In parameter estimation, parameter asymmetry introduces additional estimated parameters and results in nonlinearity and coupling among the parameters. To enhance the modeling precision and estimation performance, this paper proposes a full electrical parameter estimation method considering asymmetry. First, the universal asymmetric equations are formulated for modeling parameter asymmetry. After these equations are subjected to reparameterization, the linear regression formulations with model order reduction are yielded. Second, the dynamic regressor extension and mixing method is employed to achieve full parameter estimation. The quasi-steady state caused by the end effect ensures that the estimation equations incorporate sufficient excitation, thereby meeting the stability conditions without the necessity of external excitation. Finally, the comparative, disturbance, and control application experiments are carried out, which validate the effectiveness and merits of the estimation method.