中文摘要：

针对由级联式多电平变换器为主电路的有源电力滤波器，其主电路中直流电容相互独立，如果没有有效控制措施，这些独立的电容电压会产生不平衡，严重威胁装置的安全、稳定运行。本论文提出一种有效控制策略，不仅具有良好的补偿效果，而且保证了主电路中各级联单元直流侧电容电压恒定和均衡。为了验证所提控制方法和控制策略，本文搭建了两级级联式有源电力滤波器，实验结果表明，该系统具有良好的滤波性能，同时也保证了各级联单元直流侧电容电压恒定和均衡，进一步表明本文所提方法的有效性和正确性。

英文摘要：

High-power applications of cascaded multilevel inverter to active power filters （ APF） is hindered by the problem of keeping capacitor voltage balance while retaining good filtering performances. This paper proposes a no-vel control method with capacitor voltage balancing control for high power active power filters （ APF） using casca-ded multilevel converter. This method not only can balance the capacitor voltages of cascaded multilevel converter using for APF, but also has the better filtering characters. Firstly, the system topology of APF using cascaded mul-tilevel converter is described in detail. Secondly, the control method of APF using cascaded multilevel converter is discussed. Thirdly, a laboratory prototype of the APF based on five-level cascaded multilevel inverter is built, rated at 100kVA, to verify the capacitors voltage regulation and the harmonic filtering performance. Lastly, the experi-mental waveforms show that good filtering characteristics of the APF are achieved and the capacitor voltage is also controlled and balanced by using the proposed control methods.