混合储能系统二次功率分配及交互控制策略在直流微网中的应用

Secondary Assignment and Interactive Control Strategy of Hybrid Energy Storage Applied in DC Microgrid

针对含随机性、间歇性可再生能源的微电网中储能装置自身容量有限带来的问题,提出了混合储能系统二次功率分配及交互控制策略。文章该策略依据超级电容的荷电状态(state of charge,SOC)确定系统的工作模式。文章详细分析了各工作模式下松弛终端的协调控制方法。在临界极限充放电模式下,引入交互修正电流的概念,根据电压变化率的大小确定交互修正电流的作用区间,使超级电容的荷电状态向稳定的方向变化;在系统极限充放电模式下,提出计及充放电量并考虑SOC恢复的改变滤波时间常数的二次功率分配及交互控制策略。最后将所提控制策略应用于直流微电网中进行仿真,结果表明,该控制策略可以增强储能装置的可靠性,实现荷电状态的自恢复,减少超级电容的能量配置。

Aiming at the randomness and intermittence of renewable energy in microgrid and the problems caused by the limited capacity of energy storage devices,a secondary power assignment and interactive control strategy for hybrid energy storage is proposed.The strategy determines the operating mode of the system according to the SOC(state of charge)of the supercapacitor,and the coordinated control method of slack terminal in each working mode is analyzed in detail.In the critical limit charging and discharging mode,the concept of interactive correction current is introduced,the action interval of the interactive correction current is determined according to the magnitude of voltage change rate,so that the state of charge of the supercapacitor changes to a stable direction.In the limit charging and discharging mode,secondary power assignment and interactive control strategy that take into account the charge and discharge amount and SOC recovery change the filter time constant is proposed.Finally,the proposed control strategy is applied to the simulation of a DC micro-grid.The results show that the control strategy can enhance the reliability of the energy storage device,realize the self-recovery of the state of the charge,and reduce the capacity configuration of the supercapacitor.