中文摘要：

H桥级联静止无功补偿器（STATCOM）具有结构简单、易模块化实现等众多优点，但直流电容电压难以实现平衡控制始终是限制其广泛应用的一个重要难题。从内在机理出发对现有的电容电压平衡控制方法进行归类分析，提出控制手段的整体评价方法，为实际系统中控制策略的选取提供理论依据。搭建实验样机并基于直接功率控制完成包含直流电容电压平衡的整体控制，实验结果验证了该控制方法的有效性。

英文摘要：

H-bridge cascaded static var compensator（STATCOM） has many advantages,such as compact structure, easy sealability.One of the main disadvantages of the cascaded H-bridge converter is the voltage unbalance of direct current capacitor that could appear on the direct current side of different H-bridges.The capacitor voltage balancing control strategy from the internal mechanism is analyzed which could provide a theoretical basis for the actual system. An experimental prototype is designed, direct current capacitor voltage balancing control based on direct power control is completed, experimental results verify the effectiveness of the control method.