一种双馈风力发电机组定子低次谐波电流抑制的方法

A scheme of low harmonic current suppression for doubly-fed induction generator

电网电压的低次谐波会影响风电变流器的并网电能质量。传统的PI调节器无法有效实现对谐波的抑制,因此,文中以双馈风力发电系统为背景,在电网电压含有低次谐波电压的情况下,分析并推导了电机定转子的数学模型。通过对数学模型的分析,利用单R谐振调节器对定子电流实时分解的方式,将特定次谐波电流的调节量作为谐波电压补偿量,参与转子侧变流器控制,实现了对定子侧低次谐波电流的抑制。并利用波特图和根轨迹的方法分析了系统的稳定性及谐振调节器参数的选择方法。最终以5、7次谐波为例,通过仿真和实验验证了所提出方法的有效性。

The low harmonics of power grid voltage will have effects on grid-connected power quality in wind power converter.Traditional PI regulator can’t eliminate the harmonic effectively,and the power quality can’t meet the requirements.Thus,the resonant controller are designed in this paper.Regulating the harmonic current to compensate harmonic voltage and then control the DFIG.Considering the low harmonics voltage,this paper analyzes and derives a mathematical model of the motor stator and rotor.And by the use of a resonant,the stator current is decomposed in real-time to regulate the particular harmonic current as harmonic voltage compensation,control the converter of rotor-side,and realize the suppression of low harmonic current on stator side.The stability of the system is analyzed by the Bode program and root locus.Taking the five and seven harmonic current as an example,simulation and experimental results validate the feasibility of the scheme.