独立电力系统电压源型LCL逆变器虚拟阻尼控制

在独立电力系统中,LCL逆变器作为电压源为电网提供稳定电压,其输出谐振是影响电力系统稳定性的重要因素之一。为了提高系统稳定性,对LCL逆变器输出谐振抑制方法进行了研究,在目前采用的前馈解耦双闭环控制系统的基础上进行改进,引入虚拟阻尼代替实际阻尼,通过有源控制,选取合理的采样点和反馈位置,得到一种基于滤波电容电压前馈的虚拟阻尼控制方法。理论分析和仿真验证表明:该方法避免了额外并联实际电阻所造成的系统损耗,同时有效降低了系统输出阻抗,提高了系统的稳定裕度。

Virtual damping control of voltage source LCL inverter for independent power system

In the independent power system, LCL inverter as a voltage source for the power grid to provide a stable voltage, the resonance is one of the important factors affecting the stability of the power system. In order to improve the stability of the system, the resonance suppression method of the LCL inverter is studied. Based on the current feed-forward decoupling double closed-loop control system, the virtual damping is introduced instead of the actual damping. Through the active control, a damping control method based on filter capacitor voltage feed-forward is obtained by choosing reasonable sampling point and feedback position. Theoretical analysis and simulation results show that this method avoids the system loss caused by the extra parallel resistance, and effectively reduces the output impedance of the system and improves the stability margin of the system.