工频隔离三相并网光伏逆变器的状态反馈控制

State feedback control of three-phase grid-connected PV inverter isolated by line-frequency transformer

重点研究了三相不平衡电网电压、变压器漏感和线路阻抗对逆变器波形质量和稳定性的影响,得出了逆变器的离散状态空间模型,提出并实现了工频隔离并网光伏逆变器的状态反馈控制策略。通过仿真和试验,验证了该控制策略能有效地抑制电网电压不平衡所造成的影响,可解决变压器漏感和线路阻抗所造成的稳定性问题。

First it was studied that the grid-connected PV inverter output waveform quality and sta- bility were influenced by grid unbalance three-phase voltage, inductance leakage of transformer and circuit resistance. Then a discrete state space model of the PV inverter was established. And a state feedback control strategy of the inverter isolated by main-frequency transformer was proposed. A simulation and an experiment of the proposed strategy were achieved. The results show that the strategy effectively reduces the influence caused by unbalance grid voltage, and solves the stability problem made from inductance leakage of transformer and circuit resistance.