双馈感应风力发电机网侧变换器低压运行与控制

Operating and Control for Grid Converter of Double-fed Wind Generator under Grid Voltage Dip

电压型双PWM变换器用作双馈风力发电机的交流励磁电源在风力发电系统中得到广泛应用,但在电网故障时会引起电网侧变换器直流链电压波动,影响双馈感应风力发电机的不间断运行。分析了引起交流励磁发电机电网侧变换器直流链电压波动的因素,提出了在电压跌落时采用基于小波模型方法,通过引入恰当的前馈项,使流入母线电容的电流为零。与传统的前馈控制策略进行仿真比较分析,验证了改进的前馈控制策略能在负载突变和电网电压骤降的情况下,有效地控制变换器直流母线电压,提高了直流电压调节速度,减小了振荡幅值,同时也起到保护直流链电容的作用,提高了电力系统的稳定性。

Double-fed wind power generator wilh file dual pulse widlh modulation （PWM） conlrol voltage source converter asexcitation power supply were widely used in wind power generation system. However, the DC-link voltage of the converter willfluctuate under grid fault, which may affect the ride lhrough of Doubly-fed wind general. The factor of DC-link voltage fluctuation isanalyzed based on altened cunrent excitation generalor （ACEG）, and a small wave model wilh suitable feed forward is proposed for fileconlrol oflhe grid-side converter during grid voltage dip, to maintain a 0 level of currant into bus ber capacity under gird fault the traditional feed forward strategy, simulation and analysis shows that tile DC-link voltage of file converter can be effectivelycontrolled when load is changed suddenly and votlage dip, improving DC-link voltage regulaling speed and reduce the amplitude of the oscilltion,the DC-link capacitor can also be protected and the power system stability can be improved urder the grid fault