为克服传统光伏阵列逆变器因局部不佳而造成整体输出功率下降的缺陷,提出了一种针对单块太阳能电池板的小功率微型逆变器拓扑结构及其相应的控制策略。微型逆变器采用两级式并网结构:前级控制采用基于传统电导增量法和自适应算法的变步长最大功率跟踪算法以获得更好的动稳态特性;后级控制鉴于LCL滤波器的结构特点采用电压外环与双电流内环组成的三环控制策略以获得高品质的入网电流。在Matlab仿真环境下,利用Simpower Systems功能模块,对太阳能电池板的数学模型、最大功率跟踪算法控制策略和并网控制策略分别建立了仿真模型,仿真结果证明了该方案和控制策略的正确性。
To improve the whole drop of the traditional PV inverter caused by poor local output, a low-power micro-inverter topology and the corresponding control strategies for a single solar panel are presented. A two-stage network structure is considered for the micro-inverter. For the former control, a variable step adaptive MPPT algorithm based on traditional increment conductance method and adaptive algorithm is applied in order to get better dynamic and steady performance. Meanwhile in view of the structure and characteristics of the LCL filter, the latter control applies a strategy consisting of an outer voltage loop and a dual inner current loop for high-quality network current. Simulation model for the photovoltaic cell mathematical model, MPPT strategy and grid-connected strategy are built on the platform of Matlab by using the functional modules of the SimpowerSystems. The simulation results confirm the correctness of the scheme and control strategies.