有源中点箝位型五电平(active neutral-point-clamped five-level,ANPC-5L)变换器与三电平相比,具有输出电压等级较高、输出功率更大、电流谐波含量较低等特点,在高压大功率领域具有较高的研究价值.以ANPC-5L变换器作为研究对象,采用空间电压矢量脉宽调制控制算法,通过分析ANPC-5L变换器的单相拓扑结构及其工作原理,针对不同开关状态下的ANPC-5L变换器的母线中点电压的波动模型进行研究分析,得出了平衡母线中点电压偏差的公式及ANPC-5L 变换器中点电位的平衡域曲线.以此为基础,提出一种有效平衡中点电压的控制方法,通过选择参考电压矢量所在三角形的开关序列及同时控制复用矢量的作用时间之比,实现了悬浮电容电压与中点电压的解耦和平衡控制,最后通过实验进一步验证了控制算法的正确性和有效性.
The active neutral-point-clamped five-level (ANPC-5L) converter has been widely researched and applied. Compared with the three level converter, it has high rating of output voltage, large power and low current harmonic contents. To take the ANPC-5L inverter as a research object, a space vector pulse width modulation (SVPWM) control algorithm was adopted, by analyzing the single-phase topology of the ANPC-5L inverter and its working principle, the neutral-point voltage of the ANPC-5L inverter was studied. Under different switch states, the region of the balancing neutral-point and the adjusting formula of the neutral-point deflection have been obtained. An effective control method of the neutral-point is proposed, by selecting the switch sequence of the reference voltage vector in the triangle and controlling the reuse vector function of time, a decouple method and a balancing control of the floating capacitor voltage and the neutral-point voltage balance are achieved. Finally the correctness and effectiveness of the control algorithm were verified by experiments.