并联三相PWM变换器零序环流带宽扩展  

Circulating Current Loop Bandwidth Expansion for Parallel Three-Phase PWM Converter Connection System

作　　者：张学广[1] 陈佳明[1] 张文杰[1] 徐殿国[1] 

机构地区：[1]哈尔滨工业大学电气工程及自动化学院,哈尔滨150001

出　　处：《电工技术学报》2015年第18期69-75,共7页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金重点(51107020);国家自然科学基金(51237002)资助项目

摘　　要：三相PWM变换器并联系统运行时会产生环流。为解决并联系统环流问题,本文提出一种零序电流环带宽扩展策略。在分析并联模块环流模型的基础上,详细研究了变换器的参数差异和数字控制器的延时对零序电流环带宽的限制,利用电压零矢量前馈控制消除了变换器参数差异和运行状态不同对零序电流环带宽设计的限制,并结合单个载波周期内双次电流采样双次PWM更新方式(DSDU)有效增加了零序电流环的带宽。该方法不需要提高系统的开关频率,具有动态响应快和环流抑制效果好的优点,能够在并联模块滤波电感不同及给定电流不同的情况下,获得较好的环流控制效果。实验结果验证了理论分析的正确性和控制策略的有效性。The common dc-link dual parallel three-phase converter-system would produce circulating current. To suppress circulating current, a method to expand the bandwidth of zero-sequence current loop was proposed. Restrictions to the bandwidth of zero-sequence current loop caused by the difference in parameters between inverters and the time delayed by the control system were analyzed based on the model of parallel system. The restrictions caused by parameter difference as well as different converter operating state was eliminated with the zero vectors feed-forward strategy. Dual current sampling and dual PWM duty update method combined with the zero vectors feed-forward strategy was proposed to expand the zero-sequence current bandwidth effectively. This method has fast dynamic response and good performance of circulating current suppression, without increase in switching frequency. Both the validity of the theoretical analysis and the effectiveness of the control strategy was confirmed by experimental results.

关 键 词：三相PWM变换器并联 环流控制 带宽扩展 电压零矢量前馈 

分 类 号：TM461[电气工程—电器]