基于风力发电机典型控制策略的控制参数设计及稳定性验证

由风速变化引起的功率波动会对电力系统的稳定性以及风电系统变流器的可靠性等产生负面影响.文中基于风力发电机2种典型的功率平滑控制策略,即改进最大功率点跟踪控制和功率反馈控制,分别建立了从风速到输出功率、电磁转矩和转速的传递函数.然后,分析了风力机的稳定运行条件,合理设计了风力机稳定运行下变流器的控制器优化参数.此外,通过绘制系统的根轨迹以及分析随机风速下系统的Nyquist曲线和Bode图来进一步验证参数设计方法的合理性和可行性.最后,基于MATLAB/Simulink建立了永磁直驱风力发电系统仿真模型,检验所提出的控制器设计参数的效果.通过验证可知,优化设计下的参数能最大程度地跟踪功率、减小功率波动,同时保证风力机转速的稳定性.

Control Parameter Design and Stability Verification Based on Typical Control Strategies of Wind Generators

Power fluctuations caused by the changes of wind speed could have negative impacts on the stability of power systems and the reliability of converters in wind power systems. In this paper, based on two typical power smoothing control strategies of wind generators, namely the improved maximum power point tracking (MPPT) control and the power feedback control, the transfer functions from the wind speed to the output power, the electromagnetic torque and the rotating speed are established, respectively. Then, the stable operation conditions of wind turbines are analyzed, and the optimal controller parameters of the converter for the stable operation of the wind turbine are reasonably designed. In addition, the rationality and feasibility of the parameter design method are further verified by plotting the root locus of the system and analyzing the Nyquist curves and Bode plots of the system with random wind speeds. Finally, based on MATLAB/Simulink, a simulation model of permanent magnet direct-drive wind generation system is established to test the effect of design parameters of the proposed controller. The verification shows that the parameters with the optimal design can track the power to the maximum extent and reduce the power fluctuation, while ensuring the stability of the rotating speed for wind turbines.