A Novel Mathematical Nonlinear PMSM Realization Method for Electric Machine Emulator

Abstract

Electric machine emulator (EME) system is developed for power electronics test. The accuracy of emulator, especially the accuracy of motor model, is of vital importance in this system. The traditional lumped parameter permanent-magnet synchronous motor (PMSM) model ignores the nonlinearity. The finite-element analysis (FEA) model and the magnetic circuit analysis (MEC) are not suitable for EME real-time systems. In this article, we proposed an improved distributed parameter PMSM modeling method, which integrates the magnetic saturation, spatial harmonics, and cross coupling in a mathematical expression. The method reconstructs the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i> -axis current versus flux linkage and electric angular, rederives the electromagnetic torque, and simplifies the realization schematic. It should be emphasized that the model can be applied on the real-time running system. With these improvements, the proposed model occupies much less RAM space compared with the lookup table method. The model can mimic the harmonics and hold the merits of high accuracy and high running speed. To validate the accuracy of the proposed method, the simulations and experiments on field-programmable gate arrays (FPGAs) are carried out. Sufficient comparison among three models is implemented. The results validate the accuracy of the proposed model.