永磁同步风力发电系统附加虚拟阻尼控制仿真及验证

永磁同步风电机组(permanent magnet synchronous generator,PMSG)传动轴的扭振不仅会增加轴系的疲劳损害,严重时还会影响风电机组(wind turbine generator,WTG)的稳定性、减少机组的使用寿命。为了保证风电机组高效、稳定运行,有效抑制轴系扭振,该文详细阐述了永磁同步风电系统功率控制的基本控制策略,重点探讨与分析了控制参数与轴系阻尼对系统稳定性及轴系扭振的影响。总结出:当控制参数选择的不合适,会导致轴系扭振失稳;轴系阻尼能抑制扭振,并能够提高系统稳定裕度。基于此,该文提出一种附加虚拟阻尼的控制方法,通过在q轴电流控制环注入相应的阻尼的补偿电流,等效于引入阻尼补偿转矩、增加了轴系阻尼。所提控制策略对于抑制轴系扭振、增强机组的稳定性、增加机组的使用寿命,具有一定的现实意义与实用价值,可在轴系阻尼现实不足的情况下,可通过附加虚拟阻尼来增强轴系阻尼,进而对轴系扭振进行有效抑制。

Simulation and validation of additional virtual damping control of permanent magnet synchronous wind power system

Torsional vibration of permanent magnet synchronous generator (PMSG) shafting not only will increase the fatigue damage of the shafting, but also can seriously affect the stability and reduce the service lifetime of wind turbine generator (WTG).Torsional vibration problem of large WTG becomes increasingly prominent.In order to ensure high efficient and stable operation of the WTG, and restrain shafting torsional vibration effectively, this paper expounds the basic control strategy of permanent magnet synchronous wind power system (PMSWPS) in detail, and discusses and analyzes the influence of control parameters and shafting system damping on the system stability and the shafting torsional vibration.It is found that the instability of the shafting torsional vibration will be caused when inappropriately selecting the control parameter, and that the shafting system damping can suppress the torsional vibration, and improve system stability margin.Because of the stronger nonlinearity and complexity of direct-drive PMSWPS (D-DPMSWPS), there exists certain blindness in the setting of control parameters.This paper effectively restrained the shafting torsional vibration caused by the inappropriate parameter selection.The article puts forward a kind of additional virtual damping control method, that is, under the real condition of insufficient shafting damping, introducing the corresponding compensation current at q axis current control loop, which is equivalent to the introduction of damping torque compensation and increasing the shafting system damping.The proposed control strategy has a certain practical significance and practical value for inhibiting the shafting torsional vibration, and improving the stability and WTG service lifetime of the nonlinear complex system D-DPMSWPS, has the same control effect with the actual increase of shafting damping, and can reduce the requirement for the control parameters.We can get the following conclusions by simulation: 1) It can lead to instable torsional vibration, when the control parameter selection is inappropriate.The article chooses 2 groups of control parameters to confirm this conclusion.The first group of control parameters are kp=0.0005, ki=0.001 and T=0.1 and the second group of control parameters are kp=0.0005, ki=0.01 and T=0.1.It is found that the instable torsional vibration occurs under the first group of control parameters, but does not occur under the second group of control parameters.2) Different control parameters have different requirements on shaft system damping.For example, it only needs to increase the shaft system damping to 300 to maintain system stable under the first group of control parameters, while it need not increase the shaft system damping under the second group of control parameters.3) It can inhibit torsional vibration damping and enhance the stability margin by increasing the shafting.This phenomenon will be found that the instable torsional vibration due to unsuitable control parameter selection can be suppressed effectively by increasing damping of shafting, and the stability margin is enhanced under the first group of control parameters.4) Additional virtual damping control has the same effect with the actual increase of shaft damping and can suppress torsional vibration.The last conclusion can be validated by computer simulation that it can enhance WTG damping and restrain shafting torsional vibration effectively through introducing additional virtual damping under the real condition of insufficient shafting damping.