三电平有源中点钳位型微网储能变流器直流侧中点电压优化控制策略

摘要

对三电平有源中点钳位型微网储能变流器的直流侧中点电压平衡优化控制策略进行了研究.由于三电平半周期对称特定谐波消除脉宽调制方法(selected harmonic elimination pulse width modulation,SHEPWM)方程具有无数组解,且每组解对应的开关状态矢量不同.研究了特定谐波消除脉宽调制方法方程不同的解对应的开关状态矢量及其对中点电压的影响.提出在每个周期动态选择合适的解使中点电压趋于平衡的控制策略.该控制策略在消除特定低次谐波的同时,有效的控制了直流侧中点电压波动,因此提高了微网储能变流器并网输出电能质量和降低了对输出滤波器的设计要求.最后搭建了三电平微网储能变流器仿真模型和实验平台对所提出的控制策略进行验证,实验结果表明了该控制策略的有效性.%An optimal control strategy of the neutral point potential (NP) balancing for the three-level active neutral point clamped (3L-ANPC) micro grid energy storage converter is proposed in this paper. Due to the three-level half-wave symmetric selected harmonic elimination pulse width modulation (SHEPWM) equation has multiple solutions, and the corresponding switch state vectors of different solutions are different. The switching state vectors of the SHEPWM equation and their influences on the NP are studied. The NP balancing can be effectively controlled by choosing appropriate solutions in every fundamental period. The proposed control strategy can eliminate specific low order harmonics and also effectively control the fluctuation of NP. Therefore, the grid-connected output power quality is improved and the requirement of the output filter is reduced. Finally, the simulation model and experimental platform of three-level active neutral point clamped micro grid energy storage converter are built to verify the proposed control strategy. The simulation and experimental results are provided to verify the effectiveness of the proposed control strategy.