直流微网混合储能系统优化控制策略

Optimal Control Strategy of Hybrid Energy Storage System for DC Microgrid

和单一储能相比,蓄电池/超级电容混合储能系统可以满足微网多样化的要求。在独立直流微网系统中,根据优先使用功率密度较高的超级电容、减少蓄电池频繁大电流充放电的原则,提出了一种混合储能系统优化控制策略。加入延迟环节延迟蓄电池出力,由超级电容迅速平抑系统功率波动;根据超级电容实时荷电状态和充放电状态,采用模糊控制器调整延迟时间,在保证超级电容安全运行的前提下实现其充分利用;蓄电池作为持续供能设备,采用基于其端电压的多滞环电流控制方法,对蓄电池充放电过程进行优化,减少高频充放电电流切换造成的损伤。仿真实验结果验证了控制策略的有效性。

Compared with a single energy storage, battery/supercapacitor hybrid energy storage system （HESS） can meet multiple requirements of microgrid. In the isolated DC microgrid, an optimal HESS control strategy is proposed according to the principles of priority using supercapacitor with higher power density and reducting the fluctuation/magnitude of the charge/discharge current of battery. Adding a delay block to delay battery out- put, the power fluctuation is quickly stabilized by supercapacitor. According to the real-time state of charge （SOC） of supercapacitor and its charge/discharge status, a delay-time adjustment fuzzy controller is adopted to achieve full advantages of supercapacitor while ensuring its safe operation. A multi-hysteresis current control method based on battery voltage is adopted to improve the battery working process and reduce the damage caused by frequent current transition. The simulation results verify the feasibility of the control strategy.