An optimal control method for grid-connected photovoltaic micro-inverter to improve the efficiency at light-load condition
An optimal control method for grid-connected photovoltaic micro-inverter to improve the efficiency at light-load condition
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DOI：
10.1109/ecce.2011.6063772
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
Zhe Zhang;Min Chen;M. Gao;Qiong Mo;Z. Qian
中科院分区：
文献类型：
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作者：
Zhe Zhang;Min Chen;M. Gao;Qiong Mo;Z. Qian
微型逆变器将单个太阳能电池板的直流电 (DC) 转换为交流电 (AC)。与传统组串式逆变器相比，它们具有多种优势，例如更高的最大功率点跟踪效率、更易于安装和更长的使用寿命。对于微型逆变器的控制，选择边界电流模式（BCM）来提高效率，同时使用断续电流模式（DCM）来限制开关频率。如果 DCM 中的开关频率恒定，则轻载条件下开关损耗在总功率损耗中将发挥更重要的作用。本文首先分析了DCM/BCM控制和频率限制对效率和输出性能的影响。然后提出了一种可变开关控制方法，以减少不同光伏电池板输出功率水平和输入/输出电压变化下的开关损耗。仿真和120W样机的实验结果验证了所提出的控制方法。
Micro-inverters convert direct current (DC) from a single solar panel to alternating current (AC). They have several advantages over conventional string inverters like higher maximum power point tracking efficiency, easier installation and longer lifetime. For the control of micro-inverter, boundary current mode (BCM) is chose to improve the efficiency while discontinuous current mode (DCM) is used to limit the switching frequency. If the switching frequency in DCM is constant, the switching loss will play a more significant role in the overall power loss at light load condition. In this paper, the effect of the DCM/BCM control and frequency limitation to the efficiency and output performance is analyzed first. Then a variable switching control method is proposed to reduce the switching loss under different PV panel's output power level and input/output voltage changes. Simulation and a 120W prototype's experimental results validated the proposed control method.