采用自适应小波包分解的混合储能平抑风电波动控制策略

采用蓄电池和超级电容构建混合储能系统以平抑风电场输出功率波动,实现风电平滑并网。首先,针对不同风电出力场景下风电功率的波动特性,结合风电并网波动标准和混合储能系统性能特点,实现风电功率的自适应小波包分解和储能初级功率分配,得到风电并网功率和混合储能初级功率指令;其次,在混合储能系统内部,根据超级电容的荷电状态,利用模糊优化控制对蓄电池和超级电容的功率指令进行二次修正,得到优化后的混合储能功率分配指令。算例分析表明,所提策略能够自适应地实现风电功率的最优分解和合理分配,确保混合储能荷电状态工作在合理区间,有效改善风电输出功率波动平抑效果,保证混合储能系统长期稳定运行。

Wind Power Fluctuation Smoothing Strategy of Hybrid Energy Storage System Using Self-adaptive Wavelet Packet Decomposition

A hybrid energy storage system(HESS)consisting of battery and super capacitor is developed to mitigate wind power fluctuation and realize smooth integration of wind power. According to the fluctuation characteristics of wind power in different output scenarios, and considering the grid regulations on wind power volatility and the performance characteristics of HESS, a novel self-adaptive wavelet packet decomposition and HESS primary power distribution method is proposed, which can yield wind power grid-connected values and HESS primary power instructions. Then the HESS primary power instruction will be given secondarymodification using fuzzy optimal control inside HESS according to the state of charge(SOC)of the super capacitor, and the final HESS power distribution instruction can be determined. Simulation results show that the proposed strategy is able to achieve optimal decomposition and rational distribution of wind power, ensure the SOC of HESS working within the reasonable range, effectively improve the smoothing effect of wind power output fluctuation, and guarantee long-term stable operation of the HESS.