电网不平衡下级联型电力电子变压器的网侧谐波抑制方法研究  

Research on grid side harmonic suppression method for cascaded power electronic transformers under unbalanced grid conditions

作　　者：牛春豪 徐永海[1] 范兴管 NIU Chunhao;XU Yonghai;FAN Xingguan(State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学新能源电力系统国家重点实验室,北京102206

出　　处：《电测与仪表》2024年第9期40-47,共8页Electrical Measurement & Instrumentation

基　　金：北京市自然科学基金资助项目(3172036)。

摘　　要：低压级联H桥换流器由于采用级联结构,被广泛用于中压场合尤其是电力电子变压器的输入级,但是在电网不平衡工况下,交流侧功率波动会引起直流侧电压纹波突增进而导致网侧出现电流畸变。针对这一问题,提出了一种不平衡工况下级联型电力电子变压器网侧谐波抑制方法。文中推导分析了电网不平衡时网侧谐波的产生机理,揭示了交流侧谐波和直流侧纹波的耦合机制。基于这种机制提出了一种改进的准比例谐振控制器来抑制网侧谐波,并对控制系统的稳定性进行了分析。在PSCAD/EMTDC中搭建了仿真模型,与传统控制策略对比证明了所提谐波抑制策略的有效性。Cascaded H-bridge converter is widely used in medium voltage applications,especially in the input stage of power electronic transformer,because of its cascade structure.However,under unbalanced grid conditions,the power fluctuation on AC side will cause the voltage ripple on DC side to increase abruptly,resulting in the current distortion on grid side.Aiming at this problem,a harmonic suppression method for cascaded power electronic transformers under unbalanced conditions is proposed in this paper.The generation mechanism of grid side harmonics is deduced and analyzed,and the coupling mechanism of AC side harmonics and DC side ripple is revealed;Based on this mechanism,an improved quasi-proportional resonant controller is proposed to suppress the grid side harmonics,and the stability of the control system is analyzed;A simulation model is built in PSCAD/EMTDC,and compared with the traditional control strategy,the effectiveness of the proposed harmonic suppression strategy is verified.

关 键 词：级联H桥 耦合机制 改进的准比例谐振控制 谐波抑制 

分 类 号：TM41[电气工程—电器]