基于超级电容储能控制的双馈风电机组惯量与一次调频策略

双馈感应发电机在最大功率点跟踪控制下,发电机的输出功率难以响应电网频率波动,常规超速减载控制虽然可保留部分有功备用参与系统调频,但存在风电机组发电效益降低、转速调节范围减小及桨距角控制启动频繁等问题。为此,文中结合双馈感应发电机网侧变流器的控制特性,提出了基于超级电容储能控制的双馈风电机组惯量与一次调频策略。其中,虚拟惯量调节和一次频率调节都由超级电容控制实现,无须改变或增加风电机组额外附加控制,提高了单台风电机组的自稳性和抗扰性;根据实际超级电容模组的成本和充放电效率对储能单元容量进行优化配置。通过对比预留备用一次调频方案的经济性,表明所提方案具有较强的经济优势。最后,通过仿真实验表明其惯量支撑和一次频率调节能力及发电效益相较于常规一次频率控制具有明显提高。

Inertia and Primary Frequency Regulation Strategy of Doubly-fed Wind Turbine Based on Super-capacitor Energy Storage Control

Under the maximum power point tracking control of the doubly-fed induction generator (DFIG), the output power of DFIG is difficult to respond to grid frequency fluctuations. Although conventional overspeed load shedding control can retain active power reserve to participate in system frequency regualtion, there are some problems such as the reduction of power generation efficiency, the reduction of speed regulation range and the frequent start-up of pitch angle control. To this end, combined with the control characteristics of the grid-side converter of DFIG, a strategy of DFIG inertia and primary frequency regualtion is proposed based on super capacitor energy storage control. Both the virtual inertia and the primary frequency regualtion are realized by supercapacitor control and there is no need to change or increase the additional control of the wind turbines, which improves the disturbance resistance and self-stability of a single wind turbine. According to the actual cost of the supercapacitor module and charging/discharging efficiency, the capacity of the energy storage unit is optimized. Compared with the economics of the primary frequency regualtion scheme of active power reserve, the proposed scheme has strong economic advantages. Finally, the simulation experiments show that its inertia support, primary frequency regualtion capability and power generation efficiency are significantly improved compared with conventional primary frequency control.