基于光纤同步技术的大功率并联变流器设计

Design of High Power Parallel Converter Based on Optical Fiber Synchronization Technology

针对三相变流器直接并联运行时存在高次短路谐波电流和零序环流的问题,提出一种基于光纤同步的环流抑制技术。通过分析两台逆变器直接并联电流,发现其干扰主要由高次谐波电流和零序环流构成。而高次谐波电流主要由开关周期不一致造成,但这种谐波电流由于频率太高无法通过谐振控制进行抑制,对此利用TMS320F28377D芯片EPWM模块特有的同步引脚,实现两台变流器开关周期同步。此外引入多级并联准比例谐振控制器实现对零序环流抑制。实验结果表明,该方法可有效保证系统高效、稳定运行。

To solve the high short-circuit harmonic current and zero-sequence circulation problem in three-phase direct parallel inverter.This paper proposes a suppression technology based on optical fiber synchronization.By analyzing the parallel direct current of two inverters, founding the interference is mainly composed of high harmonic current and ze- ro sequence circulation.The high harmonic current major caused by the switching cycle inconsistency,which cannot be suppressed by the resonance control because the frequency of harmonic current is too high,so we use TMS320F28377D EPWM chip module-specific synchronization pin to achieve two converter switching cycle synchro- nize.In addition, the paper introduces a multi-stage parallel resonant quasi-proportional control loop to achieve the ze- ro-sequence suppressed.Experimental results show this method can guarantee the system operate efficiently and stably.