Research And Optimization Design Of Large Pole Changing Two-speed Asynchronous Motor

With the rapid development of China’s economy and improving of industrial modernization,electric energy consumption is becoming more and more in all the industrial fields.Motor as a unit of electrical energy into mechanical energy,is applied to various occasions in industrial production.So it becomes the main device of power consumption.But motor speed control can effectively avoid the waste of electricity according to the load’s different requirement of the rotate speed.Motor speed control divides into step-less frequency conversion timing and pole changing control.When the load doesn’t need neither high range of speed control nor step-less,pole changing control is widely adopted as a kind of lower cost solution,especially using in the fan,water pump load.Therefore,how to design high-performance pole changing two-speed motor becomes a very important subject in motor design and manufacturing.As a high-performance pole changing two-speed motor designed,it must have high utilization of stator winding under two poles,have less lead connector and use less control switch.At the same time,it must have steady electromagnetic performance which means that it’s not easy to appear the electromagnetic vibration and noise and can start with the load successfully by overcoming harmonic torque.This is the target to achieve when we designing a pole changing two-speed motor.This thesis relies on the order of a pole changing two-speed motor of circulating pump of a certain power plant.User has strict requirements on the cost of control and running performance.Therefore,this thesis researches the theory of motor pole changing and harmonic analysis,and then contrasts the characteristics of 2Y/△ and 3Y/3Y pole changing,analyses the shortage of the existing pole changing two-speed motors in detail combined with practical examples.This thesis determines the optimized scheme of 3Y/3Y+Y winding arrangement,and it’s checked to be reasonable in theory by drawing vector diagram,harmonic calculation and finite element simulation.At last,through the prototype trial-manufacture and type tests,we finally get the motor test data which proves the correctness of the optimization design of pole changing two-speed motor and the feasibility of the method put forward in the thesis.