电网不平衡下基于SGSC和Lyapunov控制器的DFIG协调控制

Coordinated control of DFIG based on SGSC and Lyapunov controller under unbalanced power grid

针对双馈异步发电机(DFIG)风电系统在电网电压不平衡时存在的问题,提出了一种改进的基于DFIG风电系统的协调控制策略,可以很好地解决这些问题。该控制策略的创新之处在于把串联网侧变换器(SGSC)与Lyapunov控制2种结构结合在一起。其中,SGSC可抑制系统输出功率2次谐波脉动,Lyapunov控制可提高系统控制性能。该策略实现了4种控制目标,即直流母线电压恒定、电网侧的有功、无功无2倍频谐波和电网侧的电流无负序分量,且还实现了定子和转子的电流平衡,DFIG输出的功率和电磁转矩无2次脉动。软件仿真平台和硬件实验平台上实验结果验证了本文所提协调控制策略具有响应速度快、鲁棒性强、控制参数少等优点。

An improved coordinated control strategy based on doubly-fed induction generator(DFIG)wind power system was proposed to solve the problem of DFIG wind power system under unbalanced power grid.Series grid-side converter(SGSC)was combined with Lyapunov controller,in which SGSC can suppress the second harmonic fluctuation of the output power of system,and Lyapunov control can improve the control performance of system.The control strategy not only realizes the 4 control targets that are constant voltage of DC bus,grid-side active power without second harmonics,grid-side reactive power without second harmonics,and grid-side current without negative sequence component,but also realizes the balance of stator current and rotor current without distortion,and DFIG output power and electromagnetic torque without second harmonic ripples.The experimental results on the software platform and the hardware platform show that the proposed coordinated control strategy has the advantages of fast response,strong robustness and less control parameters.