一种高压链式负序电流发生装置及其控制策略

A High-voltage Cascade Negative-sequence Current Generator and Its Control Strategy

由于不对称性负载的广泛存在,STATCOM的负序电流补偿能力得到越来越多的重视,但是目前还缺乏合适的高压负序电流测试装置对其性能进行准确测试。本文提出一种高压链式负序电流发生装置,并对负序电流输出下直流电压相间不均衡进行了分析,理论分析表明产生这一现象的原因是单相桥臂中负序电流与正序电压形成的有功功率,在此基础上本文提出根据相间压差通过PI控制获得零序电压从而实现负序电流输出的控制策略。最后,本文通过搭建的20 kvar链式负序电流发生装置试验平台对控制策略进行验证,试验结果证明了控制策略的有效性。

More and more attention is paid to the negative sequence current compensation ability of SATCOM due to wide existence of asymmetry load.However,there is at present a lack of a suitable high-voltage negative-sequence current generator for its performance test.In this paper,a kind of high-voltage cascade negative-sequence current generator is proposed and the dc-voltage unbalance between different phases under negative-sequence current output is analyzed.It is shown by the theoretical analysis the reason for this phenomenon is due to active power formed by the negative-sequence current and positive-sequence voltage in the single phase bridge arm and,on this basis,zero-sequence voltage is obtained by PI control in accordance with voltage difference between phases is proposed so to achieve the control strategy of negativesequence current output.Finally,the control strategy is verified by the set 20 kvar cascade negative sequence current generator test platform and the effectiveness of the control strategy is verified by the test result.