Analysis and Implementation of an Improved Flyback Inverter for Photovoltaic AC Module Applications
Analysis and Implementation of an Improved Flyback Inverter for Photovoltaic AC Module Applications
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DOI：
10.1109/tpel.2013.2279266
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发表时间：
2014-07
影响因子：
6.7
通讯作者：
M. Gao;Min Chen;Chi Zhang;Z. Qian
中科院分区：
文献类型：
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作者：
M. Gao;Min Chen;Chi Zhang;Z. Qian
反激式逆变器具有结构紧凑、控制回路简单、电气隔离、升压比高、效率高等优点，是光伏交流模块应用的一种有吸引力的解决方案。在这种拓扑中，BCM比DCM和CCM更受欢迎，因为它具有更高的功率级别、更高的效率和更宽的开关频率带宽。然而，由于开关频率可变，BCM的控制较为复杂。这也导致很难得到输出电流Iout和参考电流Iref之间的精确数学模型，这对Iout的THD有很大的影响。通过理论推导，分析并提出了BCM中IOUT和IREF之间的数学模型，并提出了一种新的控制策略来产生能够降低输出电流THD的参考电流。同时，还研究了基于该数学模型的最大功率点跟踪算法的实现。最后给出了基于改进的反激式逆变器样机的仿真和实验结果，验证了所提出的数学模型和控制策略的正确性。
Flyback inverter has the advantages such as compact conformation, simple control loop, electric isolation, high step-up ratio, high efficiency, etc., therefore is an attractive solution for photovoltaic ac module applications. In this topology, BCM is more preferred compared to DCM and CCM, because of its higher power level, higher efficiency and wider switching frequency bandwidth. However, the control of BCM is more complicated due to its variable switching frequency. This also leads to the difficulty to get the accurate mathematical model between the output current iout and the reference current iref, which has a great influence on the THD of iout. This paper analyzes and proposes a mathematical model between iout and iref in BCM through theoretical derivation, and proposes a novel control strategy to generate the reference current that can decrease THD of output current. Meanwhile the realization of MPPT based on the mathematical model is also investigated. Finally, simulation and experiment results based on an improved flyback-inverter prototype are presented, which validates the proposed mathematical model and the control strategy.