补偿双馈风电机组电磁转矩-转速闭环相位滞后特性的传动轴系统阻尼控制

Damping Control of Drive-Train System of DFIG to Compensate Phase Lag Characteristics of Electromagnetic Torque-Generator Speed Closed Loop

准确地获取双馈风电机组闭环控制回路的相位特性并对其进行合适的相位补偿是设计传动轴系统阻尼控制器的关键,为此,推导了定子磁链定向坐标系下双馈风电机组闭环系统电磁转矩-电机转速的微增量表达式,建立了阻尼转矩系数与有功控制策略、机组运行状态和控制系统参数之间的联系,据此设计了含相位补偿环节的基于电机转速信号的扭转振荡阻尼控制器,并从阻尼转矩系数分析、根轨迹分析和时域仿真3个角度验证了该控制器在不同运行状态下的有效性和鲁棒性。结果表明,在相同增益下,补偿控制系统相位滞后特性的阻尼控制比无相位补偿阻尼控制更能有效地提高扭转振荡阻尼以及降低对轴系的暂态转矩冲击。

It is a key step to obtain accurate phase characteristics of the closed-loop system of a doubly-fed induction generator （DFIG） and compensate the corresponding phase lag in the design of a drive-train system damping controller. Therefore, the closed-loop electromagnetic torque-generator speed characteristics of DFIG under small perturbations are formulated in the stator-flux orientation reference frame. This formulation also quantitatively establish the relationship between the damping torque coefficient and operating points, active power schemes as well as machine and controller parameters. On this basis, a generator speed-based damping controller is designed to mitigate torsional oscillations in the drive-train system of DFIG considering the phase lag within the torque-speed loop. The effectiveness and robustness of the damping controller with respect to various operating points are verified through damping torque coefficient analysis, root locus and time-domain simulations. It is demonstrated that for the same gain, the damping controller with phase compensation can more effectively improve the torsional damping and reduce the transient torque in the drive-train system than that without it.