基于准PR调节器电流双闭环LCL三相并网逆变器控制

摘要

复杂的电网工况下，研究高效的并网逆变器控制方法具有重要的实用价值。提出了αβ静止坐标系下基于准PR（比例谐振）调节器电流双闭环LCL三相并网逆变器控制策略，与传统的dq坐标系下PI（比例积分）控制相比，响应快速、系统稳定且能单位功率因数运行，在电网故障情况下具有很好的鲁棒性。电容电流内环反馈控制能够抑制LCL 滤波器在谐振频率处的谐振尖峰；基于静止坐标系并网电流外环控制无需对电流分量进行解耦，其控制算法简单，准PR控制基波频率处增益有限，不会造成系统不稳定，且具有抵抗电网频率波动的能力。仿真结果证明了提出的控制策略的优越性，并验证了其有效性。%The effective control of grid-connected inverters under complicated network situation is very important for the practical value. A dual-closed-loop control strategy based on grid-side current closed-loop and capacitor current closed-loop is proposed. Compared to conventional PI controller, it can ensure the system's speed, stability, unity power factor operation and good robustness during grid faults. Capacitor current inner-loop feedback control can suppress the LCL filter resonance peak, grid current outer-loop control based on stationary coordinate system needs no current decoupling, and the control algorithm is simple, quasi-proportional-resonant (QPR) has limited gain at the fundamental frequency, won’t cause system instability, and is capable to resist the grid frequency fluctuations. The advantages of this control strategy is analyzed, and effectiveness is validated by simulation.