并联整流器环流控制策略研究

Research on Circulating-current Control Strategy for Rectifiers in Parallel

并联整流器会增加系统的容量以及效率,但是在实际工程中由于电感参数不相等或输出电流不相等都会产生环流,环流会增加输入电流谐波。为了抑制环流,提出一种修正的比例谐振控制器,实现低次零序谐波控制。首先对并联整流器进行详细的建模分析,然后改变零矢量作用时间实现零序环流抑制。此外,为了能够更好地抑制并联整流器的零序环流,在上述基础上,提出一种双采样零序环流抑制方法,以实现整流器并联的最优控制。仿真和试验表明:和现有方法相比,新方法的零序环流抑制能力增强,输出电流波形得到进一步改善。

While rectifiers in parallel could raise system capacity and efficiency,different inductance parameters or different output currents in actual engineering would generate circulating current,which would in turn increase harmonics of the input current. In order to restrain the circuiting current,this paper proposed a modified proportional resonant controller to realize low-order zero-sequence control.Firstly,a detailed modeling analysis was made for the rectifier in parallel. Then,the zero-vector action time was changed to realize zero-sequence control of circulating current. Furthermore,for the purpose of better suppression of the zero-sequence circulating current of the parallel rectifier,on the above mentioned basis,this paper proposed a double sampling zero-sequence suppression method for circulating current so as to realize optimal control of parallel connection of rectifiers. Simulation and test results indicated that,compared with current method,the proposed approach could give better suppression of the zero-sequence circulating current,and the waveform of the output current could be further improved.