基于混合储能的微电网功率控制策略

Power Control Strategy for Microgrid Based on Hybrid Energy Storage System

微电网中间歇式微电源输出功率较大的不确定和波动,给微电网孤网运行时的电能质量和并网运行时的功率可调度控制带来了巨大的挑战。采用单一的储能系统平滑功率波动,不仅无法很好解决上述两种问题,且不利于延长储能元件的寿命。文中利用超级电容的高功率密度、快速充放和蓄电池适于平抑长周期功率波动的特点,提出了基于超级电容和蓄电池组成的混合储能系统及相应的控制策略,微电网孤网运行时采用超级电容平滑波动频率较高的功率,并网运行时结合蓄电池平抑频率较低的功率,通过两者的共同作用提高了微电网孤网运行的电能质量与并网运行的可调度性,同时避免了蓄电池频繁充放电。在PSCAD/EMTDC中建立微电网仿真模型,验证了所提出的混合储能结构及其控制策略的可行性。

The output fluctuation of intermittent micro-power in mircrogrid will bring great challenge to the control of power quality at the island operation mode and the power schedu｜ability at the grid-connected operation mode. Using one type of energy storage system to smooth the power fluctuation is hard to perfectly solve the above prob- lems but is not good to extend the life of energy storage device. This paper proposes a control strategy based on hy- brid energy storage system consisted of super-capacitor and battery, which takes advantage of the battery to smooth long-periodic fluctuation power and the high power density, fast charge and discharge of the super-capacitor. The super-capacitor is used to smooth the high fluctuation power when the microgrid on island operation mode. By com- bining with the battery, the super-capacitor can be used to smooth the low fluctuation power when the microgrid on grid-connected operation mode. Therefore, the power quality on island operation mode and schedulability of the mi- crogrid on grid-connected operation mode can be improved, and too much charge and discharge of the battery can be avoided. A simulation model of microgrid is built by PSCAD, and simulation results verify the feasibility of the proposed hybrid energy storage construct and control strategy.