| With the rapid development of hydropower construction in China,the unit size and single unit capacity are getting larger and larger,the relative rigidity of the unit is weak,and the unit vibration problem induced by nonlinear factors such as hydraulic,electromagnetic and mechanical is more prominent.Therefore,it is very necessary to establish a nonlinear model of the hydro-generator system based on a comprehensive consideration of a variety of nonlinear factors,and then to study the vibration control of the unit system.In this paper,by introducing magnetorheological damper(MRD)into the nonlinear dynamic model of the hydro-generator shaft system,a nonlinear dynamic model of the hydro-generator shaft system based on magnetorheological fluid is established.The position of the damper,the effects of the magnetorheological damper on the vibration control of the shaft system of the unit and the vibration control of the unit considering the basic excitation are systematically studied.The paper mainly uses numerical analysis methods to obtain the following results:(1)Based on the innovative introduction of magnetorheological damping material,a nonlinear dynamic model of hydro-generator-based shafting system based on magnetorheological fluid is established.On this basis,the control effect of MR damper on the vibration of hydro generator shafting under low speed operation and high speed operation under transient condition is analyzed.(2)Using the basic theory of optimization,by setting the position parameters,the position parameters are introduced into the dynamic model of magnetorheological damper,and the nonlinear rheological force model of magnetorheological fluid with positional parameters is established.The influence of different arrangement positions of the damper on the vibration of the hydro-generator unit is studied,and the optimal interval of the damper arrangement is determined.It has certain reference value for engineering practice.(3)Based on the nonlinear dynamic model of magnetorheological fluid turbine generator set,the fuzzy control model of magnetorheological fluid unit is established by fuzzy control.Through the fuzzy control rules,the energy consumption function of the magnetorheological damper is utilized to a greater extent,and the vibration of the shafting of the unit under passive control is compared and analyzed.The results show that the control effect on the vibration of the unit shaft is improved.(4)Considering the influence of the foundation on the vibration of the unit,the basic excitation is assumed to be a combination of harmonic and random excitation,and the basic excitation is transmitted to the unit through the guide bearing.The effects of basic excitation on unit vibration under different parameter groups are studied,and the effect of the improved nonlinear damping force model on the vibration control of unit under basic excitation is analyzed. |
