调节阀特性非线性补偿对动态特性影响的仿真研究

调节阀特性非线性将影响机组的稳定运行,必须通过非线性补偿,使机组的静态特性线性化。液压调节系统通过凸轮转角与阀门升程特性的调整实现线性化,数字电液调节系统通过非线性补偿函数实现系统特性的线性化。通过计算机仿真,对不同补偿方式时系统的动态特性进行了研究,结果表明,当油动机滑阀没有限幅时,两种系统的补偿环节对动态特性没有影响;当油动机滑阀具有限幅时,数字电液调节系统补偿特性对系统的动态特性具有重要的影响,为了保证系统的稳定,必须限制补偿环节的斜率或者负荷扰动的幅值。为调节系统补偿环节的设计提供了理论依据。

Simulation Study of Non-linear Compensating of Control Valve Property on System Dynamic Response Characteristics

The stability of steam turbine control system could be effected by the governing valve nonlinear position-flow characteristic.In order to obtain a linearization static governing property for the unit,the nonlinear valve property should be compensated.In the hydraulic control system,usually a cam and its angle-valve position characteristic is used to compensate the nonlinear property.As in digital electro-hydraulic(DEH) control system,a nonlinear compensation function is used to make the property linearization.In this paper,the dynamic properties of the governing system with different compensation methods are analyzed by simulation and some results are obtained.There has no effect on the dynamic property of the system when the motion of the pilot valve of the actuator is unlimited with different compensating method.But the dynamic property of the DEH control system is significantlly effectted by the compensation function when the motion of the pilot vale is limited.The system could be unstable with the increasing of magnification of the compensation function and the load disturbance.In order to keep the stability of system,the magnification of the compensation and the value of the load disturbance should be limited in a range.A theory element is provided for the design of the control system compensating function.