共直流母线多逆变回路并联系统环流分析及其抑制

Circulating Current Analysis and Suppression in Multi Inverting Parallel System with Common DC Bus

共直流母线全桥多逆变回路并联系统在容量配置灵活性、冗余可靠性及直流储能元件利用率方面具有十分明显的优势。然而,当多个逆变回路输出电压幅值或相位存在偏差时,必须考虑系统间环流问题。通过分析系统环流产生机理,得出环流与逆变电流及逆变电压之间的关系,并在此基础上提出一种基于负载电流瞬时均分的统一环流抑制策略,将负载电流均分值与输出电流实际值之间的偏差引入闭环控制,对电压指令进行调整,从而保证各逆变回路输出电压幅值及相位的一致性。最后,仿真及实验验证了所提环流抑制策略可行性与正确性。

The parallel structure of multi full-bridge inverters has obvious advantages in capacity configuration flexibility and redundancy reliability as well as the availability of energy storage components with a common DC bus.However,in case of deviation in amplitude or phase of the output voltage,the problem of circulating current should be considered.Firstly,the relationship between circulating current and the inverting current as well as inverting voltage is obtained by way of analyzing the generating mechanism of circulating current and,on this basis,a unified circulating current suppression strategy based on instantaneous sharing of load current is proposed,which can adjust the order of voltage after introducing the deviation between current target value and actual value into closed-loop control and make sure the consistency of output voltage amplitude and phase of each inverting circuit.Finally,the feasibility and correctness of the proposed circulating current is verified by the simulation and experiment.