高速永磁同步电机驱动系统具有电磁时间常数小、高速区载波比低的特征，加剧了电流纹波，影响系统效率、振动噪声和电磁干扰。为降低高速永磁同步电机的电流纹波，基于SiC-MOSFET/Si-IGBT混合型逆变器设计了一种改进型低损耗空间矢量调制算法。首先，通过调整零电压矢量的生成方式和各功率器件的开关动作时序，将大部分开关动作转移至低损耗的SiC-MOSFET中，并为高损耗的Si-IGBT提供零电压开关条件，降低了逆变器损耗，提高了驱动系统的效率和可用开关频率，逆变器开关频率的提高有效降低了电机电流纹波。其次，对该算法作用时的电流纹波特性进行深入分析，在此基础上提出一种变开关频率模式的最优交轴电流纹波峰值调制算法以优化交轴电流纹波性能。然后，根据预测的交轴电流纹波峰值实时调整载波频率，通过削峰填谷的方式对交轴电流纹波进行平均，在不增加开关损耗的条件下，分散开关能量、降低转矩脉动、改善振动噪声和电磁兼容性能。所提方案的优势在于：较于传统型逆变器，逆变器开关损耗降低、效率提高，可进一步提升开关频率以改善电流纹波；较于传统空间矢量调制算法，改进了电压矢量的生成方式，并利用载波频率这一新增自由度分散能量，降低了交轴电流纹波。最后，通过仿真与实验对所提出算法的有效性进行了验证。
The High-Speed Permanent Magnet Synchronous Motor (HSPMSM) drive system has two characteristics: small electromagnetic time constant, and low carrier frequency ratio of high-speed zone. These two non-ideal factors cause severe current ripple, which affects the efficiency, vibration noise and electromagnetic interference of the HSPMSM drive system. To suppress the current ripple, an improved low-loss space vector modulation algorithm is proposed based on a SiC-MOSFET/Si-IGBT hybrid inverter. The generation method of the zero voltage vector and the switching operation sequence are adjusted to transfer most switching actions to SiC-MOSFET and provide zero-voltage switching conditions for Si-IGBT. The switching loss of the inverter is then reduced, thereby improving the efficiency of the system and the available switching frequency. Improvement of the switching frequency effectively reduces current ripple. To further optimize the ripple performance, the ripple characteristics are analyzed. An optimal peak quadrature-axis current ripple modulation algorithm is proposed based on the variable switching frequency mode. The carrier frequency is adjusted in real time according to the predicted peak value of q-axis current ripple. The q-axis current ripple is averaged by means of peak load shifting, so as to disperse switching energy under the condition that the average switching frequency remains unchanged. The electromagnetic compatibility performance and vibration noise are improved. The proposed scheme has the advantages as follows: compared with the traditional inverter, the switching loss is reduced, the efficiency is improved and the switching frequency is increased to reduce the current ripple; compared with the traditional space vector modulation algorithm, the voltage vector generation method is improved. The carrier frequency is used to disperse the energy, and the peak value of the quadrature axis current ripple is reduced. Simulations and experiments executed on a HSPMSM verify the effectiveness of the proposed algorithm.
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