When the conventional hybrid frequency (HF) modulation strategy applies to the asymmetric cascaded H-bridge (ACHB) inverter with dc voltage in a ratio of 1:1:2, there are uneven problems of switching loss in low-voltage cells and output power over all operating cells. Thus, a modified HF based on a dual-layer power balance (MHF-DPB) modulation strategy was presented. First, step modulation was still applied to a high-voltage cell on the basis of the conventional method, but improved level-shifted pulsewidth modulation (LS-PWM) was applied to two low-voltage cells. Subsequently, the power balance between high-voltage and low-voltage cells was controlled by adjusting the conduction angles of the power switch and then the carriers of the two low-voltage cells were rotated periodically in order to realize the two low-voltage cells’ power balance. The proposed method can not only realize the power balance of cascaded cells, but also distribute the switching loss of two low-voltage cells equally. In the meantime, it reduced the total switching loss of the inverter. Finally, it was validated by simulation and experimental results.

中文翻译：

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九电平不对称级联H桥逆变器模块功率分配平衡的新型调制方案


传统的混合频率（HF）调制策略应用于直流电压比例为1：1：2的非对称级联H桥（ACHB）逆变器时，存在低压电池开关损耗和输出功率不均匀的问题覆盖所有操作单元。因此，提出了一种基于双层功率平衡（MHF-DPB）调制策略的改进的高频。首先，在传统方法的基础上仍然对高压电池应用步进调制，但对两个低压电池应用改进的电平移位脉宽调制（LS-PWM）。随后，通过调节功率开关的导通角来控制高压和低压电池之间的功率平衡，然后周期性地旋转两个低压电池的载流子，从而实现两个低压电池的功率平衡。权力平衡。该方法不仅可以实现级联电池的功率平衡，而且可以平均分配两个低压电池的开关损耗。同时，降低了逆变器的总开关损耗。最后通过仿真和实验结果对其进行了验证。