局部阴影下光伏阵列自适应MPPT方法研究

RESEARCH ON ADAPTIVE MPPT METHOD FOR PV ARRAY UNDER PARTIAL SHADE

光伏阵列受局部阴影、个别光伏组件故障等影响,输出P-U特性呈多峰现象,此时传统最大功率点跟踪(MPPT)往往无法跟踪到真正的全局最大功率点(MPP)。为了避免由此导致的光伏阵列输出功率大幅度损失,在深入研究阴影条件下光伏阵列多峰功率特性的基础上,提出一种自适应全局MPPT方法。当光伏阵列的输出P-U特性发生变化时,该方法能自适应调整跟踪策略寻找到全局MPP。20 k Wp光伏阵列仿真实验和统计分析结果表明,该方法在超过90%的阴影案例中,能准确快速平稳地跟踪到真正的全局MPP,且对开路电压和短路电流估测误差具有鲁棒性。实验测试结果表明:该MPPT方法能在局部阴影发生前后跟踪到光伏阵列的全局MPP。由于原理简单、所需传感器数量少、MPPT跟踪性能优异,自适应MPPT方法具有较好的应用前景。

Affected by characteristic curve. Us partial shade or PV module＇ s fault, et al, there may be muhiple peaks on PV array＇ ually conventional maximum power point tracking （MPPT） algorithms are unable to s output P-U find the real global maximum power point （MPP） for this case. In order to avoid considerable output power loss of PV array, the multi- peak＇ s characteristic of PV array under shades is studied in depth, and an adaptive global MPPT method is proposed. When PV array＇ s output P- U characteristic varies, the proposed algorithm can adaptively adjust tracking strategies to find global MPP. Simulation and statistical analyses on a 20 kWp PV array were carried out. The results shown that the adaptive MPPT method can track the real global MPP accurately, quickly and smoothly under more than 90% shade cases, and it is robust to estimation errors on open-circuit voltage and short-circuit current of the PV array. Experimental results shown that the proposed MPPT method tracked out global MPP of PV array before and after partial shade successfully. Due to simple theory, less sensors needed and outstanding MPPT performance, the adaptive MPPT proposed in this paper will have a good application prospect.