Analytical Calculation of Performance of Line-Start Permanent-Magnet Synchronous Motors Based on Multidamping-Circuit Model

This article presents a new analytical method for calculating performance of line-start permanent-magnet synchronous motor (LSPMSM) based on multidamping-circuit model (MDCM) to take spatial harmonic components of LSPMSM into account. First, MDCM of damping bar in the rotor is established according to Kirchhoff's current law. Second, an eleven-order system of LSPMSM is deduced from a group of differential equations according to the equations of flux linkage, voltage, torque, and motion. Then, starting process of LSPMSM is simulated with the proposed analytical method, including speed, current, and electromagnetic torque waveforms versus time, respectively. The starting performance and synchronization capability are analyzed and compared under different effective value of input phase voltage, moment of inertia, and load torque. The simulation time with finite element method is about 1235 times longer than the simulation time with the proposed analytical method to calculate the starting process of LSPMSM with the same computer. Finally, the validation of the developed analytical method based on MDCM is verified by comparing simulating results with experimental results and direct axis and quadrature axis (DQ) model. The results based on this new method are reliable. It is conducive to calculate, analyze, and design LSPMSM with less time.