一种计及总损耗功率估计与转速前馈补偿的飞轮储能系统放电控制策略

A Discharge Strategy for Flywheel Energy Storage Systems Based on Feedforward Compensation of Observed Total Dissipative Power and Rotational Speed

针对飞轮储能系统放电过程中飞轮转速迅速下降、直流侧功率突然变化等因素影响母线电压动态性能和稳定性的问题,该文在传统飞轮PI放电控制策略基础上,提出一种计及总损耗功率估计与转速前馈补偿的飞轮储能系统放电控制策略。采用电容储能比例反馈控制,利用非线性扰动观测器对电机与变流器损耗功率、负载功率等总损耗功率进行统一观测,并引入转速补偿环节对系统进行直接前馈补偿控制;根据闭环控制系统的主导极点图和伯德图,分析系统的稳定性与抗扰动性能,并给出一种控制器参数的选择方法。该控制策略调节参数少、无需负载侧的电流传感器、控制结构简单。仿真和实验结果表明,所提放电控制策略和参数选择方法能够有效抑制飞轮转速迅速下降和直流侧负载突变对母线电压的影响,系统鲁棒性得到提高。

In the discharge process of flywheel energy storage systems(FESS),the DC-link voltage’s dynamic response performance and stability are susceptible to the rapid decrease of flywheel speed,the sudden change of DC-side power,and etc.To cope with this issue,this paper proposed a discharge strategy with respect to total dissipative power observation and rotational speed compensation based on traditional PI method by using proportional feedback control of DC-link capacitor’s energy with direct feedforward compensation of flywheel velocity and total dissipative power which was observed by a nonlinear disturbance observer and contained DC-side load and power consumed by the machine and converter.Parameters of the proposed discharge strategy were designed through analyzing stability and anti-disturbance property of the closed system with the dominant pole map and the Bode diagram.Only few coefficients and a simple structure without load current sensors were owned by the proposed strategy.Simulated and experimental results demonstrate effectiveness of the proposed methodology and parameter design method on the regulation of DC-link voltage facing variation of flywheel speed and DC-side power,indicating that robustness of the system is improved.