一种单相非隔离光伏并网逆变器的控制设计

Control Design of Non-Isolated Single-Phase Photovoltaic Grid-Connected Inverter

提出了对高频非隔离型光伏并网逆变器采用电流跟踪控制和电网电压前馈控制的策略,并对控制系统建模。建立了逆变器的单相并网仿真模型。仿真得到的输出正弦电流波形良好。针对实际电网电压可能出现的畸变、电压突变和光伏电池功率变化等情况进行了抗干扰测试。经试验样机上用DSP来实现数字化控制,验证了基于并网控制策略的光伏逆变器方案能高功率因数0.996向电网发电,动态响应快、鲁棒性强、跟踪精度高,并网电流的总谐波畸变小于3.5%。

For high frequency non-isolated photovoltaic（PV） grid inverters, a current tracking control and grid voltage feedforward control strategy was proposed. The mathematical model of its control system was built. Singlephase inverter feeding grid simulation model was established. The results show that sinusoidal output current is good. An experimental prototype was adopted via DSP digital control. Both simulation resuhs and experimental waveforms verify the feasibility and correctness of the design which is successfully applied in a PV power generation prototype with high power factor of O. 996. Based on the grid connecting control strategy, the inverter can generate electricity to the grid, having fast dynamic response, strong robustness with a high tracking precision, fast response, small total harmonic distorition of less than 3.5%.