为最大化地降低可再生能源输出功率的波动程度,优化混合储能系统的运行,采用时间常数随储能系统荷电状态变化的低通滤波算法确定目标功率值;根据蓄电池和超级电容的荷电状态,采用模糊控制理论将超出目标值的功率偏差在两种储能介质之间进行分配;当超级电容电量充足时,由其独立补偿功率偏差值,以减少蓄电池的充放电次数。算例分析表明,所提控制策略能够有效地平抑可再生能源功率波动,避免储能介质出现荷电状态越限现象,达到延长蓄电池使用寿命的目的。
For reducing the fluctuation of renewable energy output power in maximum degree and optimizing the operation of hybrid energy storage system (HESS), this paper adopted the low-pass filtering algorithm whose time constant was mixed with the state of charge (SOC) of HESS to determine the goal output, and adopted the fuzzy control theory to distribute the power deviation out of the leveling target between two energy storage mediums, according to the SOCs of batteries and supercapacitors. For reducing the number of times of battery charging and discharging, the supercapacitors compensate the power deviation independently when their energy was adequate. Numerical results showed that the control strategy could effectively level the fluctuation of renewable energy power, avoid the out-of-limit phenomenon of energy storage mediums, and achieve the purpose for prolonging batteries' life.