基于退役动力电池储能的光储微网系统

锂电池作为光储微网的储能电池,能够提高光伏发电系统的稳定性,改善电能质量,但成本高昂。将电动汽车的退役动力锂电池用于光储微网的储能单元,不仅可以降低投资成本,还可以缓解大批量电池进入回收阶段的压力。首先基于锂电池的工作原理,构建了退役动力锂电池的等效电路模型。接着建立了储能变流器和多重双向DC/DC变换器级联拓扑,储能变流器采用电压外环、电流内环的双闭环策略,稳定直流母线的电压;多重双向DC/DC变换器采用以电池组的荷电状态(SOC)为约束条件的双闭环控制策略,平抑光伏发电系统的功率波动。最后搭建了基于退役锂电池储能的光储微网系统,验证了控制策略的有效性。

Photovoltaic/Battery Micro-Grid System Based on Energy Storage of Decommissioned Power Battery

As a storage battery for micro-grid, lithium battery can improve the stability of photovoltaic power generation system and improve power quality, but the cost is high. The use of decommissioned lithium battery of electric vehicle for energy storage unit of photovoltaic/battery micro-grid can not only reduce investment costs, but also alleviate the pressure of large-scale batteries entering the recycling phase. Based on the working principle of lithium battery, the equivalent circuit model of lithium battery is constructed. Cascaded topology of energy storage converter and multiple DC/DC converters is investigated. The energy storage converter uses a double-closed-loop strategy of voltage outer loop and current inner loop to stabilize the voltage of the DC bus. The multiple bidirectional DC/DC converter adopts a double-closed-loop control strategy based on the state of charge (SOC) of the battery pack to stabilize the power fluctuation of the photovoltaic power generation system. An photovoltaic/battery micro-grid system based on decommissioned lithium battery energy storage is built to verify the effectiveness of the control strategy.