基于推挽正激电路的准单级式光伏并网逆变器仿真分析

Simulation Analysis on Quasi-Single-stage Grid-Connected Photovoltaic Inverter Based on Push-pull Forward Converter

针对两级式光伏并网逆变系统结构复杂、成本高、效率低的不足,研究了一种单级式光伏并网逆变系统。采用电流瞬时值反馈控制、双模式MPPT算法和直流母线电压前馈控制的方法,研究了单级式光伏并网逆变系统并网电流的正弦控制、最大功率点跟踪控制和光照突变下系统的稳定性,并对300VA光伏并网逆变系统进行了建模仿真。研究结果表明,单级式光伏并网逆变系统具有并网电流质量高、动态特性好、最大功率点跟踪精确、效率高、光照突变适应性强、稳定性高等优点,在要求电气隔离的分布式并网逆变场合具有广阔的应用前景。

A single-stage grid-connected photovoltaic system was investigated to overcome the drawbacks of two-stage gridconnected photovoltaic system such as complex structure, high cost and low efficiency. It has researched the grid-connected current sinusoidal control, maximum power point tracking （MPPT） and the system stability under the rapidly change of light intensity, which were based on the instantaneous current feedback control, dual mode MPPT and DC-link voltage feed-forward control. At last, the model of 300VA PV grid-connected system was built and simulated to verify the theoretical analysis. The research results demonstrate that the single-stage grid-connected system have many advantages such as high quality and good dynamic characteristics of grid- connected current, accuracy MPPT, high efficiency, strong adaptability to the rapidly change of light intensity, high reliability etc. Therefore, it can be deduced that this kind of PV system has a wide application prospect in the place where the grid-connected inverter requires electrical isolation.