基于混合脉宽调制的并联并网变换器控制方法

摘要

The parallel three-phase grid-connected converters sharing direct current and alternating current buses can increase the system level,but the circulating current problem is inevitable.According to an analysis of the causes of the circulation,the circulation problems caused by the injection of different zero-sequence voltages are studied.A mathematical model of the circulating current is developed and a modulation scheme combining sinusoidal pulse width modulation (SPWM) and space vector pulse width modulation (SVPWM) is proposed.It is expected that the voltage utilization can be increased,the low-frequency circulation due to the injection of different zero-sequence voltages should be avoided.Finally,the experiment platform of parallel three-phase grid-connected converters is set up in the laboratory to facilitate experiments and verify the feasibility and effectiveness of the proposed modulation method.%共享直流母线和交流母线的三相并网变流器并联系统可以提高系统容量,但不可避免地带来环流问题.在分析环流产生原因的基础上,研究了由于注入不同零序电压引起的环流问题,建立了环流的数学模型,提出了一种正弦脉宽调制(SPWM)与空间矢量脉宽调制(SVPWM)结合的调制方式,既能提高电压利用率,又能避免由于零序电压注入不一致引起的低频环流问题.最后,在实验室搭建了变流器并联运行的实验平台,通过相关实验验证了所提出的调制方法的可行性和有效性.