三相LCL型并网逆变器双电流环控制器设计

Design of dual current loop controller for three-phase LCL-type grid-connected inverter

并网逆变器在当前电网中具有举足轻重的地位。本文针对三相LCL型并网逆变器进行了研究,建立了其数学模型,给出了其双电流环控制器的设计方法,并针对于常规双电流环控制稳定裕量低的弊端,提出了一种改进型双电流环控制策略。最后,进行了仿真验证,分析表明,在较为理想的模型下,两种双电流环控制策略均具备较为优秀的控制效果,但在非理想模型下,所提改进型控制策略具备更大的稳定裕量,更适合在实际数字控制系统中应用。

The grid-connected inverter plays an important role in the current power grid. In this paper, the three-phase LCL-type grid-connected inverter is studied, and its mathematical model is established. Based on that, the design method of dual current loop controller is given. Moreover, an advanced dual current loop control strategy is proposed aiming at improving stability margin. Finally, the validity of the design results is analyzed and verified by simulation. The analysis indicates that both two current control strategies have excellent control performance when the model is ideal,however, the advanced current control strategy proposed in this paper shows larger stability margin in the scenario where more non-ideal factors are considered and is more suitable for application in practical digital control systems.