设计了一台基于DSP控制的3 kW光伏并网逆变器，阐述了其关键技术，提出了一种基于恒压法和扰动观测相结合的MPPT新算法以及一种优化的基于主动频率偏移法的主动孤岛检测新方法。对电流控制策略作了简要介绍，经Matlab系统仿真和实际实验结果表明，系统有较好的稳定性和快速的动态跟踪特性，并网电流总谐波畸变率较低(THD<4%)，并且与电网电压同频同相。%The design of a 3 kW photovoltaic grid-connected inverter was presented. Firstly, the key technique for inverter was discussed in detail. A new MPPT algorithm, which was based on the combination of constant pressure and disturbance observation method was presented. In addition, one optimized islanding detection method based on frequency drift was also proposed. And then the current control strategy was introduced. The results of simulation and actual experimental show that it makes system has better stability and fast dynamic response characteristics, and lower total harmonic distortion rate ( THD less than 4%) and the inverterd current in synchronism with network voltage.
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