Abstract In this paper, an enneagon multi-level converter (E-MMC) is proposed, which can directly connect six-phase wind power generator to AC grid. It has the advantages of high efficiency, small fluctuation of capacitor voltage of sub-modules (SMs), and no need of step-up transformer. The working principle of the converter is analyzed, and the optimal phase shifting angle between the two windings of the six-phase wind turbine is determined under different boost ratios. The voltage stability control strategy of the converter and the current tracking control strategy based on proportional resonance (PR) are proposed. The simulation and experiment verify the effectiveness of the proposed system and its control strategy from both steady and transient aspects.

中文翻译：

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基于enneagon MMC变换器的六相风力发电机交/交流并网

摘要 本文提出了一种可将六相风力发电机直接接入交流电网的多电平变换器（Enneagon Multi-Level Converter，E-MMC）。具有效率高、子模块(SM)电容电压波动小、无需升压变压器等优点。分析了变流器的工作原理，确定了不同升压比下六相风力机两绕组间的最佳移相角。提出了基于比例谐振(PR)的换流器电压稳定控制策略和电流跟踪控制策略。仿真和实验从稳态和瞬态两个方面验证了所提出的系统及其控制策略的有效性。