Research And Design Of High Power High Voltage Pole-Changing Two-Speed Asynchronous Motor

Pole changing double speed asynchronous motor is a kind of speed regulating motor,which has the advantages of simple structure,convenient operation,more economy,etc.it is widely used in the occasion of low speed regulating performance requirements for fans,pumps,etc.,and can play a good energy-saving effect.The pole changing motor studied in this paper is a high-power high-voltage pole changing asynchronous motor with a rated power of 5600 / 3500 and a rated voltage of 10.The specific research content is divided into the following aspects:Firstly,this paper analyses the theory and method of pole-changing,and designs two design schemes of stator winding using reverse pole-changing method based on unified design method.By comparing and analyzing the two schemes through the calculation of winding magnetic potential and current balance,the optimal scheme with smaller harmonic of winding magnetic potential and favorable for variable front pole and variable rear pole is obtained,and the optimal pitch selection for both poles is given.Secondly,when the number of slots is given to 72 slots,the common slot matching is selected to avoid additional torque.Based on the stator winding designed in Chapter 2 of the electromagnetic field theory,the two-dimensional transient magnetic field model of Pole-changing motor with different slot matching is established.Maxwell in Ansys is used to calculate the time-stepping finite element method to calculate the pole-changing.The influence of three different multi-slot combinations on the magnetic field is studied by analyzing the change of no-load magnetic field and load magnetic field under two series.Then,the effect of slot matching on the starting characteristics and loss characteristics of the pole-changing motor studied is analyzed.The simulation results are analyzed,and the different torque curves under no-load and load are obtained.The starting torque,maximum torque,rated torque and starting current of Pole-changing motor with different slots are analyzed,and the influence of slot-matching on the starting performance of motor is analyzed.On the basis of the magnetic field analysis in the third chapter,the changes of iron loss,stator copper loss and rotor copper loss of pole-changer motor under no-load and load operation are studied,and compared with the existing experiments,the influence of slot fit change on motor loss characteristics is obtained.Finally,the amplitude and order frequency of the radial electromagnetic force of the rake-pole motor are solved by analytical calculation method.Based on the fundamental wave and harmonic distribution of the radial magnetic density obtained in Chapter 3 and its Fourier analysis,the spatial and temporal distribution of the radial electromagnetic force of the motor is obtained.The influence of different slot matching on the amplitude of electromagnetic force of Pole-changing motor's front pole and rear pole is analyzed,and the optimal slot matching selection for reducing electromagnetic noise of Pole-changing motor is obtained.