变流器参数不一致下的无互联线并联方法研究

摘要

The wireless parallel system applied in auxiliary inverters of urban rail transit system is susceptible to parameter inconsistencies,which will cause unbalanced current of parallel system.In order to solve the prob-lem,the paper analyzed the unbalanced current and pointed out that output impedance inconsistence is the root cause of unbalanced current.On this basis,the paper proposed a control strategy.Firstly,the proportional droop coefficient was expanded to reduce the influence of parameter inconsistencies and to balance output cur-rent,but it gave rise to the drop of output voltage at the same time.Secondly,the voltage amplitude of each phase obtained from Park transformation was compared with rated voltage,to compensate output voltage am-plitude.With the application of the above steps,the unbalanced current problem was solved.A large number of simulations and experiments were carried out to prove the effectiveness of the proposed theory and method.%城轨交通辅助变流器无互联线并联系统易受参数不一致影响，使得并联系统无法准确均流。为了解决这个问题，本文深入分析了不均流现象，指出输出阻抗不一致是输出不均流的根本原因。在此基础上，文章提出了一种控制策略，首先通过增大比例下垂系数，减弱参数不一致的影响，使得并联系统均流，但同时也引起了输出电压跌落；其次通过 Park 变换得到各相电压幅值并与额定电压进行比较，补偿输出电压幅值。通过以上两步措施，有效解决不均流问题。论文进行了大量仿真和实验，充分验证所提理论和方法的有效性。