基于负载电流前馈补偿的网侧变流器控制

Control strategy research of grid side converter based on load current feedforward compensation

保证母线电压恒定是风电系统稳定传输能量的关键,当电网受到扰动时,快速控制变流器响应,保持功率平衡,以使并网系统保持稳态运行.根据功率平衡原理,结合前馈和反馈的优点,利用小信号分析法,提出一种负载电流的前馈控制策略.引入负载电流前馈项,抵消来自系统故障下的扰动,缓和了风电系统能量失衡,保证了直流电压稳定.系统仿真波形显示,该策略不仅缓和了直流侧电压暂态波动,还能发出无功功率帮助系统恢复稳态运行.

The grid side converter of wind power generation system as the intermediate link is mainly used to transmit power, improving the quality of power transmission, and ensure the bus voltage keep stable is the key to the stability of wind power system. When the power grid is disturbed, it can control the converter response quickly and keep the power balance, so that the grid connected system can be kept stable. We put forward a load current feedforward control strategy, which based on the principle of balance of power by combining with the advantages of feedforward and feedback and using the small signal analysig method. In order to guarahtee the stability of DC voltage, we easy the energy imbalance for wind power system, offset from the system fault disturbance, and introduce load current feedforward. According to the system simulation waveforms, the feedforward compensation strategy is proposed, which not only helps to alleviate the transient fluctuation of the DC side voltage, but also helps the system to restore the steady state operation.