不平衡负载下三端口电力电子变压器二倍频功率解耦控制策略
Double Fundamental Frequency Power Decoupling Control Strategy for Triple-port Power Electronic Transformer Under Unbalanced Loads
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摘要: 电力电子变压器(powerelectronictransformer,PET)作为分布式可再生能源发电设备和交直流负荷灵活接入的有效解决方案,在交直流混合微电网中极具研究前景。其中,分布式电源和负荷的间歇性波动及不平衡交流负载的接入是影响PET端口输出电能质量的重要因素,PET多个端口之间的耦合作用会进一步影响其他端口负荷的正常运行。因此,研究不平衡负载工况下多端口PET的功率解耦控制策略非常关键。该文针对含交/直流端口的三端口PET拓扑结构,建立交流端口接入三相不平衡负载下PET二倍频功率传输模型,提出一种基于谐振控制的二倍频功率解耦策略,实现二倍频功率在PET不同端口间的解耦。最后,通过建立基于RT-Lab的硬件在环实验平台,验证所提控制策略的有效性。Abstract: Power electronic transformer（PET） has been increasingly investigated in the AC/DC hybrid micro power system as the power flexible interface of distributed renewable energy power generation equipment and AC/DC load. Intermittent fluctuation of distributed power supply and unbalanced AC loads are important factors to deteriorate the power quality of PET ports. The power coupling effect among multiple PET ports can degrade the normal operation of PET system. Therefore, it is of great significance to investigate the power decoupling control strategy of PET under unbalanced AC loads condition. Aimed at the topology of triple-port PET, the double fundamental power transmission model was built in this paper on the condition of the AC port connected with unbalanced three-phase AC loads, and a double fundamental frequency power decoupling control strategy based on the resonant controller was proposed, which can achieve the decoupled control target on the double fundamental frequency power. Finally, the experimental results based on the hardware-in-loop platform with RT-Lab were given to validate the effectiveness of the strategy.
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