Analysis And Design Of Dual PWM Converter For Brushless Doubly-fed Pulsed Alternator

Brushless doubly-fed machine(BDFM)is a new type of AC induction motor,which is widely used in the fields of variable frequency speed regulation,variable speed constant frequency power generation,marine shaft power generation,wind power and hydroelectric power generation.BDFM eliminates brushes and sliding rings,has simple structure and high reliability.It also has many operation modes,such as synchronous operation,asynchronous operation,doubly-fed operation,and its power factor can be adjusted.When the speed changes,the motor can maintain constant voltage output of power winding and has high power density.It is concluded that the above advantages of BDFM are suitable for high energy storage and high power repetitive pulsed charging power supply system,and for fast charging of high voltage energy storage capacitor.Therefore,this paper proposes the research of capacitor charging power supply(CCPS)system based on BDFM.Through this research,on the one hand,it expands the application field of BDFM and applies it to pulsed power generation;on the other hand,it explores a brand new technical scheme of capacitor repetitive charging,enriching the technical means of pulsed power supply.The main research contents of this paper include:Firstly,working principle of brushless doubly-fed pulsed alternator(BDFPA)is mastered,and its mathematical models in static three-phase coordinate,double rotor speed coordinate and double synchronous speed coordinate are built.Based on that,Direct Voltage Control(DVC)strategy of control winding side converter based on double synchronous speed coordination mathematic model and Current-voltage Double Closed-loop Control(CVDCC)strategy of power winding side converter based on AC side voltage orientation are studied and proposed.In addition,the scheme of CCPS system based on BDFPA is studied,and the circuit topology of BDFM for capacitor charging is analyzed.Dual PWM converter matched with BDFM is mainly analyzed and designed,which includes main circuit design,hardware design and software design of the control system.Finally,the simulation models of power winding side converter and control winding side converter are established in Simulink of MATLAB and the corresponding simulation research is carried out.Among them,power winding side converter studies the characteristics of unity power factor operation,dynamic response and energy bidirectional operation.The simulation results show that CVDCC strategy could achieve control objectives of constant DC-side voltage,fast response of AC-side voltage to load changes and bidirectional energy flow.The simulation experiments of control winding side converter in the process of no-load and capacitor charging are conducted respectively.The simulation results show that DVC strategy is feasible.Under no-load condition,the output voltage of the power winding is constant.In the process of capacitor charging,the charging time is relatively short.