摘要：SPWM逆变器在工作时产生共模电压，会诱发电机轴电压、引起轴电流，可能损坏电机轴承。文章结合高速永磁同步电机调制波频率较大的特点，对共模电压的频谱及影响因素进行了理论推导和仿真分析。结果表明：死区时间对共模电压幅值和谐波含量影响较大；死区时间一定，载波频率增大，共模电压幅值增大、谐波含量减小；管压降和上升沿、下降沿对其影响可忽略不计。上述结论对进一步深入研究永磁同步电机轴电流具有重要参考价值。

关键词：永磁同步电机；共模电压；死区效应
Abstract: SPWM inverter generates common-mode voltage at working status. The common mode voltage induced shaft voltages, and common mode currents may damage the motor shaft bearing. In this paper, combining the characteristics that the modulation wave′s high frequency of  permanent magnet synchronous motor, carried a theoretical derivation and simulation analysis on the spectrum and factors of the common-mode voltage. The results showed that: The dead time affects the common mode voltage amplitude and harmonic content; When the dead time is constant, the amplitude of common mode voltage increases and the harmonic content of common mode voltage reduces with the increase of carrier frequency; The impact of tube voltage drop and the rising edge, falling edge is negligible. The above conclusion brings important reference value for the further research of shaft currents of permanent magnet synchronous motor.

Key words: permanent magnet synchronous motor; common mode voltage; dead time effect