一种适用于LCL型并网逆变器的有源阻尼策略

An Active Damping Strategy for LCL-type Grid-connected Inverter

基于LCL滤波器状态变量反馈的有源阻尼(AD)方法具有实现简单、鲁棒性强的优点,但需要配备高精度传感器,增加了系统成本。此处提出基于负带通滤波器等效二阶微分环节反馈进网电流以实现AD的方法,可与进网电流控制器共用同一个电流传感器。详细讨论了提出的AD方法的参数设计方法,并分析了其稳态、动态、延时补偿和背景谐波抑制特性。最后,建立了并网逆变器样机验证了上述分析的正确性。

Active damping(AD) strategies based on LCL filter states variables feedback have the advantages of simple implementation and strong robustness,but need high-precision sensors.As a consequence,the cost of the system would be high.A method based on the equivalent second-order differential link of negative band-pass filter is proposed to feedback the incoming current to realize AD.The advantage of proposed AD strategy can share the current sensor with grid-connected current controller.Furthermore,the parameters design method of proposed AD strategy are discussed,as well as steady-state and dynamic performance,delay compensation and harmonic restriction from the grid have been analyzed in detail.Finally,a grid-connected inverter prototype is built to verify the correctness of the proposed strategy.