一种基于Boost并联结构的新型DMPPT系统设计

Anew DMPPT system design based on Boost parallel structure

光伏发电站工作时,常常会受到外界环境和元器件不匹配等诸多问题的影响,从而会影响发电的效率。分布式最大功率跟踪(DMPPT)概念的提出,在一定程度上弱化了上述影响。但是现有DMPPT架构直接可用于并网发电的较少,因此提出一种基于新型DMPPT架构的光伏并网发电系统。对MPPT一个光伏串列,再给每个光伏串列配备一个DC-DC变换器,并联后获取统一的直流电压,紧接着通过一个大功率逆变器将电能输送给电网。该系统大大减少了光照不均、阴影遮挡对系统发电效率的影响,降低了对系统控制的复杂程度和成本。通过仿真验证了此控制方法的有效性。

Photovoltaic power stations are often affected by many problems in operation such as the mismatch of external environment and interior components,which will affect the efficiency of power generation.The model of distributed maximum power tracing(DMPPT)weakens the above influence to some extent.However,few existing DMPPT architectures can be directly used for grid-connected power generation,so this paper proposed a new grid-connected photovoltaic power generation system based on DMPPT architecture.This paper compared and analyzed the topological structure of MPPT converter,and finally decided to adopt Boost parallel structure.In this system,multiple photovoltaic panels were connected in series to form a PV series,and then a DC-DC converter was equipped for each PV series.After parallel connection,the unified DC voltage was obtained,followed by a high-power inverter to transmit the power to the grid.The system greatly reduces the influence of uneven illumination and shadow shading on the system's power generation efficiency,and reduces the complexity and cost of system control.For the last part,the effectiveness of this control method is verified by simulation.