Differential evolution and common-mode current-based modeling of permanent magnet synchronous motors

The equivalent circuit models of permanent magnet synchronous motors (PMSM) are crucial for investigating electromagnetic compatibility (EMC). In this paper, a new model with fourteen circuit components per phase is proposed, aimed at predicting common-mode (CM) currents in a wide frequency range, from 10 kHz to 30 MHz, during motor operation. Initially, based on experimental measurements of CM and differential-mode (DM) impedance characteristic curves, the component parameters of resonant circuits in the model are identified. Then, an improved differential evolution (I-DE) algorithm, which incorporates a novel mutation strategy, is adopted to optimize and fit the model, selecting optimal individuals within the population to enhance the search efficiency and convergence speed. When compared to standard differential evolution (S-DE) algorithms and genetic algorithms (GAs), the I-DE algorithm shows superior performance in both fitting precision and computation time. Experimental results demonstrate that the established model can accurately predict CM currents, laying a solid foundation for further research on suppressing electromagnetic interference (EMI) in PMSMs.