Research On New Brushless Doubly-fed Machine And Its Variable Frequency Speed Regulating System

High voltage-high power motor is widely used in fan and pump industry,using variable frequency speed saving energy is about the consensus of all countries,but the high voltage inverter is high cost and technology is immature,The brushless doubly fed motor without brush and slip ring has the advantages of good stability,the small capacity frequency converter has been payed attention in the world.Countries around the world have invested a lot of manpower and material resources around brushless doubly fed motor research,the new type brushless doubly fed machine power winding uses high voltage drive,the control winding uses low voltage frequency control is the focus of research,it reduces the capacity and the voltage grade of the frequency converter,suitable for high voltage and high power drive,is considered to be the best solution for high power inverter.The new brushless doubly fed machine has the advantages of stable speed regulation,high motor voltage level,high reliability,and so on.However,the relevant research about its speed control system is still at the initial stage.In view of this,this paper studies the performance of the new type brushless doubly fed machine speed control system,focusing on the analysis of the steady-state operation of the new brushless doubly fed machine speed control system under vector control.First,the article analysis of the stator and rotor structure model of brushless doubly fed machine,and analyzes the working principle and working mode of the motor,a detailed analysis of the energy flow in doubly fed operation;2.Then we establishe up the mathematical model of brushless doubly fed motor in the three-phase static coordinate and dq coordinate system at the same time,the analysis of the mathematical model of dual PWM converter,the mathematical model of equivalent circuit of single-phase motor under,finally introduces the new control method of brushless doubly fed machine;3.using the mathematical model to build a new 400kW speed control system of brushless doubly fed machine in Matlab/Simulink simulation the software,and simulates the situation of motor running in steady state,asynchronous mode,impact excitation simulation observation of motor performance through the inverter,the simulation results show that the motor can be stable operation;4.Finally,the converter using 400kW model of BDFM prototype and 250kW adopts vector control method to test the initial rotor position locating,and the motor is running in asynchronous mode,double fed mode test,the test results verify the feasibility of a new brushless doubly fed motor control of the the vector,can control the motor speed effectively.