含源网络中复合储能式电力电子变压器的协调控制

Coordinated Control of Composite Energy Storage Power Electronic Transformer in Source Network

因电力电子变压器(power electronic transformer,PET)自身难以应对电网电压的跌落或中断,为提升含源网络中PET低压直流侧的电能质量,拟将多类型复合储能系统的多端口DC/DC变换器与光伏系统结合,以应用于工程实践。首先采用能量流均衡控制优化多端口蓄电池,使各荷电状态接近同一值。后引入超级电容来补偿负荷突变的高频分量,减小充放电对蓄电池的冲击。再采用功率分配型控制对光伏系统进行并网,与复合储能系统进行协调控制,对系统的稳定性进行优化。仿真结果表明,光储协调控制能提高PET的功率补偿能力以及对新能源的消纳能力,验证了光储系统应用在低压直流侧的有效性,提高了系统的稳定性。

Since the power electronic transformer(PET) itself is difficult to cope with the drop or interruption of grid voltage,in order to improve the power quality of the low-voltage DC side of PET in the active network,it is proposed to intends to combine the multi-port DC/DC converter of multi-type composite energy storage system with photovoltaic system for engineering practice.Firstly,the multi-port battery was optimized by energy flow balance control to make the state of charge close to the same value.After that,the supercapacitor was introduced to compensate for the high-frequency component when the load changes abruptly,which reduces the impact of charging and discharging on the battery.Then the power distribution control was used to connect the photovoltaic system to the grid and coordinate with the composite energy storage system,so as to optimize the stability of the system.The simulation results show that the coordinated control of optical storage can improve the power compensation ability of PET and the consumption ability of new energy,which verifies the effectiveness of the application of optical storage system in low voltage DC side and improves the stability of the system.