基于虚拟电阻的LCL型并网逆变器阻尼控制

An Active Damping Control Strategy for LCL Grid-Connected Inverter Based on Virtual Resistor

针对LCL型并网逆变器的谐振问题,采用滤波电容器串联电阻器、滤波电容电流负反馈、滤波电容电压负反馈等传统的阻尼方法会增加系统的损耗或者成本。为此,文章提出一种虚拟阻尼控制方法,其基于逆变器侧电流反馈,与滤波电容器串联电阻器方法等效,不仅能有效抑制并网电流谐振、提高系统稳定性,而且不增加附加成本和系统功率损耗。dSPACE半实物仿真结果和分布式光伏电站500 kW并网逆变器实验结果验证了该方法的有效性。

For the resonance of LCL grid-connected inverter, traditional solutions are damping as filter capacitor and resistance in series, filter capacitor current feedback, filter capacitor voltage feedback and so on, but these approaches lead to increased losses or costs of the system. By derivation the equivalent relation of filter capacitor in series with resistor, a novel active damping method based on inverter output current feedback was presented, which can effectively inhibit grid current resonance and improve the system stability with no additional cost and system power loss. The experiment of dSPACE HIL simulation platform and the experiment of 500 kW inverter in the distributed photovoltaic power station verified the validity of the method.