| Megawatt-level high-voltage induction motors have been widely used in various energy fields because of their advantages of large capacity and good economic performance.The wind path of most megawatt-level high-voltage induction motors is a closed structure,and the heat on the rotor side comes from the double superposition of the rotor guide bar and the rotor core,and the contact area between the rotor side and the motor cooling medium is small,so the rotor side heating is more serious than the motor as a whole.Therefore,how to reduce electromagnetic loss in the limited space of the motor and reasonably design the motor cooling structure to improve the heat dissipation capacity of the megawatt-level induction motor is of great significance to the stable operation of the motor.Dissertation takes a 3550 kW/10 kV three-phase two-pole high-voltage induction motor as the research object,and analyzes the electromagnetic loss and heat suppression of the megawatt-level high-voltage induction motor.Starting from the electromagnetic theory of the motor,combined with the electromagnetic structure parameters of the motor,the finite element simulation model of the motor is established,the loss distribution characteristics of the motor under rated working conditions are analyzed,the accuracy of the model establishment is verified by comparing the simulation and experimental monitoring results,and the influence of different air gap and rotor materials on the electromagnetic performance and electromagnetic loss of the motor is studied on this basis.In order to study the fluid flow law and heat transfer process of megawatt-level high-voltage motor,this paper establishes a three-dimensional fluid-structure interaction model of the motor from the fluid network theory,including motor stator and rotor,fan,air gap,back wind chamber,etc.Under the premise of considering timeliness and accuracy,the motor winding is reasonably simplified,and the overall model is axially cut,and 1/8 of the fluid-structure interaction domain is intercepted as the solution model of this paper.Taking the average wind speed on the fan side as the boundary condition of the solution domain,the motor fluid field and temperature field are solved,the distribution law of the motor fluid field and temperature field is analyzed,the accuracy of the simplified model is verified by simulation and experimental comparison,and the influencing factors of excessive temperature rise on the rotor side of the motor are determined.Through the simulation of the fluid field and temperature field of the original motor,the influencing factors of the temperature rise distribution of the motor are analyzed and discussed.Taking the motor fan structure,air gap and rotor guide strip material as variables,by comparing the temperature rise distribution on the rotor side of the motor under different schemes,an effective scheme to reduce the temperature rise on the rotor side was selected,and finally provided a reference for the suppression of rotor temperature rise of the engineering prototype. |
