一种基于直流微网技术的新型地铁能量回馈系统

Metro energy feedback system based on DC microgrid technology

针对地铁传统能馈系统中刹车回馈能量损失较大的问题,提出了一种新型地铁能量回馈系统及其控制与能量管理策略。首先,所提出的新型能馈系统相比传统方案,通过引入超级电容与UPS电池构建混合储能,实现了列车刹车回馈能量的全部吸收,减小了牵引网侧直流母线电压波动和牵引变电站的功率峰值要求,同时充分整合站内浮充UPS资源,降低储能设备成本。随后,分析了系统源荷储在理想状态下的功率分配,并基于直流母线电压信号的下垂控制,提出一种可实现电池SOC复位的改进下垂控制方案,有效控制了牵引直流母线电压并合理分配了功率。并通过对电池SOC的闭环控制,在保证UPS应急功能正常工作下,充分发挥了电池的功率平滑优势。仿真和实验验证了所提出新型地铁能馈系统的可行性与有效性。

Aiming at the large loss of regenerative braking energy, a novel metro energy feedback system was proposed and its control method and energy management strategy were studied. First, the proposed energy feedback system and the traditional system were compared. By introducing the hybrid energy storage device consisting of supercapacitor and UPS battery, the proposed solution can absorb all the regenerative braking energy, reduce the voltage fluctuation and peak power demand of traction grid, make full use of the idle UPS resources in the station and reduce the cost of energy storage device. Then, the ideal power distribution relationship between source, storage and load was analyzed. Based on droop control commonly used in microgrids, the enhanced droop control method for battery SOC reset was proposed, which can effectively control the traction bus voltage and allocate the power reasonably. The closed-loop control of the battery SOC can fully utilize the smoothing ability of the battery and ensure the emergency function of UPS. Simulation and experimental results verify feasibility and effectiveness of the proposed energy feedback system and its control method.