基于LCL滤波的双馈风电变流器有源阻尼法

LCL filter-based active damping method for doubly-fed wind power generator's converters

在双馈风电变流器中,LCL滤波器通常串联在网侧变流器与电网之间来抑制开关频率周围的电流纹波。提出基于LCL滤波的双馈风电变流器新型有源阻尼方法,即根据测量的电网电压和LCL滤波器网侧电流,计算得到LCL滤波器的电容电压,并将该电容电压经过有源阻尼模块加到网侧变流器电流环的输出电压指令上。对系统稳定进行分析,给出合适的网侧变流器电流环比例增益;并分析有源阻尼系数对系统稳定的影响。仿真结果验证了该有源阻尼方法的有效性。

In the converter circuit of a doubly-fed wind power generator, an LCL filter is usually connected in series between the grid-side converter and the grid to suppress current ripple around switching frequency. A novel active damping method of the converter based on LCL filtering is proposed, in which the capacitance voltage of the LCL filter is calculated according to measured grid voltages and filter＇s grid-side current, and the calculated voltage is added to output voltage instructions of the grid-side converter＇ s current loop through an active damping module. Appropriate proportional gain of the grid-side converter＇ s current loop is given depending on the system stability analysis. The effect of the active damping coefficient to the system stability is also studied. The final simulation results show the validity of the proposed method.