光伏电源单向并接市电的无逆流供电系统

Non-countercurrent power supplies with one-way parallel connection between photovoltaic inverter and mains

分布式光伏发电自发自用可避免谐波逆向馈入电网造成供电质量下降及其带来的监管困难。设计了光伏逆变器通过交流单向隔离电路与市电联合对负载供电的并线不并网防逆流方案。光伏直流输入经市电正弦波包进行SPWM同步调制及DC-AC同步逆变,既防止了逆变输出逆流进入电网产生干扰的可能性,也避免了并网对技术要求苛刻带来的系统复杂性以及入网监控的管理成本。实验测试结果表明,系统运行稳定,峰值效率为91.2%,是一种既节能又经济的光伏应用方案。

Self-consumption of distributed photovoltaic power generation can avoid the deterioration of power supply quality and the supervision difficulties caused by the reverse entry of harmonics into the grid. A parallel but not grid-connected scheme of photovoltaic inverter powered to the load by AC anti-backflow and municipal electricity is designed. The SPWM synchronous modulation and DC-AC synchronous inversion of photovoltaic DC input through the sinusoidal wave packet of the grid not only prevents the possibility of interference from the inverter output counter current into the grid, but also avoids the system complexity caused by the strict technical requirements of grid-connected and the management cost of grid-connected monitoring. The experimental results show that the system runs stably and the peak efficiency is 91.2 %, which is an energy-saving and economic photovoltaic application scheme.