扩大级联H桥光伏并网逆变器运行范围的控制策略  

Control Strategy for Expanding the Operating Range of Cascaded H-bridge Photovoltaic Grid-connected Inverter

作　　者：袁义生 朱启航 刘伟 YUAN Yisheng;ZHU Qihang;LIU Wei(School of Electrical and Automation Engineering,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学电气与自动化工程学院,南昌330013

出　　处：《电力系统及其自动化学报》2023年第11期50-57,共8页Proceedings of the CSU-EPSA

基　　金：国家自然科学基金资助项目(52067007,52367020);江西省自然科学基金资助项目(2023ACB204024)

摘　　要：级联H桥光伏并网逆变器由于输入功率不平衡而导致功率大的级联单元发生过调制现象,从而引发电网电流畸变。为解决此问题,提出一种新型控制方式。所提控制方法通过引入适量的基波至过调制单元调制波中,使得过调制单元的调制波由幅值超过1的正弦波变为幅值为1的正弦波,调制度始终不超过1,并将引入的基波按各单元可承受能力反向补偿至其他非过调制单元,从而抵消在过调制单元中引入基波的影响,解决了过调制问题,扩大了级联H桥光伏并网逆变器调制范围。所提方法可将调制范围扩大至1.27,扩宽了级联H桥光伏并网逆变器稳定域的运行范围。The cascaded units with large power will be overmodulated due to the unbalanced power input to a cascaded H-bridge photovoltaic grid-connected inverter,thus leading to the grid current distortion.To solve this problem,a novel control method is proposed in this paper.By introducing an appropriate amount of fundamental wave to the modulated wave of the overmodulated unit,the modulated wave changes from a sine wave with amplitude larger than 1 to a sine wave with amplitude equal to 1,with the modulation index not higher than 1 all the time.The introduced fundamental wave is compensated to other non-overmodulated units according to their capacities respectively,thus offsetting the in⁃fluence of the fundamental wave introduced to the overmodulated unit.The proposed method can extend the upper bound of modulation range to 1.27,and expand the operating range of the stability domain of the cascaded H-bridge photovoltaic grid-connected inverter.

关 键 词：级联H桥 光伏并网逆变器 基波补偿 功率平衡控制 稳定域 过调制 

分 类 号：TM464[电气工程—电器]