摘要
针对光伏发电因光照强度与温度变化而导致的发电功率波动问题,提出一种储能型光伏并网发电系统,以抑制并网功率的波动。以光伏发电最大功率跟踪和并网逆变控制为基础,引入蓄电池储能系统,实现对发电功率削峰填谷、平抑的功能。光伏发电系统采用两级功率变换结构,以最小化逆变器容量,解耦最大功率控制与逆变并网控制。在逆变器直流母线上并接双向DC/DC变换器,对储能电池充放电予以管理。在功率平抑控制中,储能系统采用双环控制,内环控制储能电池电流,外环则分两种情况:1)电网正常时为功率外环;2)电网故障时为电压外环。系统不仅具有最大功率跟踪和并网发电功能,还具有并网功率平抑功能。当电网因故障而断开时,系统将光伏发电能量储入蓄电池,提高了发电效率,确保了直流母线电压稳定。对整个系统建立仿真模型和实验样机,仿真和实验结果验证了所提出的控制方法可行、有效。
An energy storage-based grid-connected photovoltaic（PV） power generation system is proposed to overcome the fluctuation of grid-injected power caused by the change of illumination intensity and temperature.On the basis of Maximum Power Point Tracking（MPPT） and grid-connected DC/AC conversion,a battery-based energy storage control system is employed to smooth the grid-injected power.Two-stage power conversion structure is adopted to minimize the capacity of switching devices and make the MPPT and DC/AC control decoupling.A bi-directional DC/DC converter couples the DC link bus to control the charging and discharging of battery bank,and double closed-loops improve the performance of energy storage system,where the inner loop controls the battery current and the outer loop controls the grid-injected power normally or DC link voltage when the grid disconnects.The proposed system not only has the function of MPPT and grid-connected generation,but also possesses the ability of power stabilization.It can keep the DC-link voltage constant through storing solar energy in the battery during the grid fault,which will improve the power generation efficiency greatly.The simulated model and experimental model of the whole system are estabilished and the simulated and experimental results verify the feasibility and effectiveness of the proposed control system.
出处
《电力系统保护与控制》
EI
CSCD
北大核心
2011年第3期29-33,共5页
Power System Protection and Control
基金
台达电力电子科教发展计划基金资助(DREG2009006)
关键词
光伏发电
最大功率跟踪
并网逆变
储能系统
功率平抑
PV power generation
MPPT
DC/AC conversion
energy storage system
power stabilization
