A composite strategy that combines selective harmonic elimination pulsewidth modulation (SHE-PWM) and model predictive control (MPC) for seven-level hybrid-clamped (7L-HC) inverters is presented in this article. By introducing the unified SHE formulation, all seven-level switching patterns and corresponding switching angles can be obtained simultaneously. Therefore, the optimal switching pattern with the designed optimization goal of each modulation index can be evaluated, and the best expected output performance is achieved. For the voltage balancing issue of 7L-HC, MPC is adopted to control the dc-link and flying capacitors. After receiving the output voltage level signal from the SHE-PWM modulator, the optimal switching state that belongs to the received output voltage level that minimizes the cost function is selected by the MPC module, where the cost function is designed to simultaneously balance capacitor voltages and reduce the switching frequency. Dynamic weighting factors with variable band limits are also proposed to further improve the system performance. The potential industrial application of high-power motor drive is used as an example in designing the key parameters for both SHE and MPC parts. Simulation and experimental results confirmed the validity of this composite SHE-MPC strategy in reducing the switching frequency and improving harmonic performances while keeping capacitor voltages well balanced.

中文翻译：

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具有最优开关模式的七电平混合钳位逆变器的复合选择性消谐模型预测控制

本文介绍了一种将选择性谐波消除脉宽调制 (SHE-PWM) 和模型预测控制 (MPC) 相结合的复合策略，用于七电平混合钳位 (7L-HC) 逆变器。通过引入统一的 SHE 公式，可以同时获得所有七级开关模式和相应的开关角度。因此，可以评估具有每个调制指数的设计优化目标的最佳开关模式，并实现最佳的预期输出性能。对于7L-HC的电压平衡问题，采用MPC控制dc-link和飞跨电容。MPC模块在接收到来自SHE-PWM调制器的输出电压电平信号后，选择属于接收到的输出电压电平使代价函数最小的最优开关状态，其中成本函数旨在同时平衡电容器电压并降低开关频率。还提出了具有可变频带限制的动态加权因子以进一步提高系统性能。在设计 SHE 和 MPC 部件的关键参数时，以大功率电机驱动的潜在工业应用为例。仿真和实验结果证实了这种复合 SHE-MPC 策略在降低开关频率和改善谐波性能同时保持电容器电压良好平衡方面的有效性。在设计 SHE 和 MPC 部件的关键参数时，以大功率电机驱动的潜在工业应用为例。仿真和实验结果证实了这种复合 SHE-MPC 策略在降低开关频率和改善谐波性能同时保持电容器电压良好平衡方面的有效性。在设计 SHE 和 MPC 部件的关键参数时，以大功率电机驱动的潜在工业应用为例。仿真和实验结果证实了这种复合 SHE-MPC 策略在降低开关频率和改善谐波性能同时保持电容器电压良好平衡方面的有效性。