传统光伏储能发电系统都是由光伏阵列和储能电池组构成的,但这种结构易受光伏电池阴影效应及储能电池均衡性问题的影响。基于此,提出了一种由单体光伏电池和单体储能电池构成的新型光伏储能发电系统。该系统中,单体光伏电池和与之电压、容量匹配的单体储能电池构成光伏储能模组,一定数量的模组串联后组成串联支路,经升压型DC/DC电路汇流至直流母线,多个串联支路并联后向直流负载或经逆变器向交流负载供电。通过监测光伏电池、储能电池的电压电流,光伏储能模组能够在5种工作模式间切换以实现模组内的"自治"控制;同时,通过监测DC/DC变换器的输入电压,实现了光伏储能模组投入与切出的支路级控制。以太阳能的利用效率为衡量标准,提出了一种模组内光伏电池电压,参数的选择方法。最后,建立了新型发电系统的仿真模型,从原理上通过仿真验证了该光伏储能发电系统的可行性和有效性。
Traditional PV/energy storage generating system is composed of photovoltaic array and storage cell, which easily suffers from PV cell’s shadow effect and energy storage cell’s equalization. Therefore this paper proposes a novel PV/energy storage generating system consist of single PV cell/single energy storage cell. In this generating system, single PV cell and single energy storage cell having the matched voltage and capacity with the former constitute PV/energy storage module. A certain number of modules are connected in series to form a series branch, which is connected to the DC bus by boosting DC/DC converter. Series branches are connected in parallel to supply power to DC load or to AC load via inverter. The PV/energy storage module has 5 operating modes, which are switched autonomously by monitoring PV cell and energy storage cell’s voltage and current. The series branch, containing PV/energy module switch-in and switch-off, is controlled by monitoring the input voltage of DC/DC converter. This paper also proposes a method of choosing the PV cell’s voltage parameter in the proposed module based on the criteria of utilization efficiency of solar energy. At last, the simulation model of the new generating system is built, which shows the feasibility and effectiveness of the system theoretically.