| The brushless doubly-fed machine(BDFM)is a new type of AC excited induction machine,with simple structure and excellent durability.Compared with the double-fed induction machine,it removes the brush and slip ring structure,has wider operation speed range,higher reliability,longer service life and lower maintenance cost.The BDFM can be used for both grid-connected and independent power generation,so it has broad application prospects in the field of ship shaft power generation and wind power.The brushless doubly-fed independent generator system consists of the motor and the AC excitation control system,which is a high-end equipment combined with motor technology,numerical control technology and power electronic technology.In this paper,the brushless doubly-fed independent generator system is taken as the research object and the corresponding mathematical models are established.The traditional vector control strategy bases on power winding(PW)flux linkage or voltage orientation of BDFM is abandoned,proposes control winding(CW)current decoupling control strategy under the control winding synchronous rotating coordinate system according to control winding current vector orientation.The experimental platform of the brushless doubly-fed independent generator system is established and the experimental research of the system operation control is carried out.The main contents of this paper includes the following several aspects:The dynamic model of BDFM in three-phase ABC coordinate system is deduced,on this basis,the dynamic model of BDFM in any speed rotary dq coordinate is deduced.To carry out an equivalent transformation of traditional Π-type steady-state model of BDFM,and then derives a new T-type steady-state model of BDFM,which is more suitable for the performance analysis of the brushless doubly-fed independent generator system.And then obtain the mathematical model of stand-alone power generation operation on the basis of the dynamic model of BDFM in rotary two-phase dq coordinate.Based on the dynamic model of BDFM in rotary two-phase dq coordinate,the design principles of each control loop of control winding side converter are derived,proposes a complete control strategy of control winding side converter under the condition of symmetrical load;derives the mathematical model of power supply side converter at the synchronously rotary coordinate,design of current inner loop controller and DC bus voltage outer loop controller,finally presents a complete control strategy of power supply side converter.According to the mathematical model of BDFM and its control system,the simulation model of brushless doubly fed generator system is built in Matlab/Simulink.and complete the simulation experiment of velocity perturbation and load disturbance,the validity of the proposed control strategy in this paper is verified.A set of experimental platform of the brushless doubly-fed independent generator system is established,and a comprehensive experimental study of the system are carried out under the condition of symmetrical load,the experiment and result analysis show the effectiveness of the control strategy which is proposed in this paper. |
