Design And Analysis Of A Brushless Self-excited Air-core Compensated Pulsed Alternator

Compensated pulsed alternator(CPA)is a synchronous generator integrated with the inertial-energy-storage and magnetic flux compensation technologies to provide high pulsed power and current for the small load.Air-core CPA(ACPA)is a kind of CPA with high energy density,high power density and good excitation adjustability.It is one of the most potential miniaturized high energy pulse power sources.Compared with iron-core CPA(ICPA),ACPA has the problems of too large excitation power and rotary speed,which is a severe burden for the brush and slip mechanism.It makes the whole APCA system low-reliability and low-safety.Thus,a brushless self-excited air-core compensated pulsed alternator(BSACPA)is proposed in this paper.Rotating alternative current excitation is employed in BSAPCA.Combining pulsed self-excitation and separate-excitation,not only the topology can adjust the excitation current,but also solve the problem of the serious wear and heat of the brushes and slips.In addition,a motor/generator integrated BSACPA is also presented in this paper,which integrates the prime motor,initial excitation and BSACPA,making the system more miniaturized.The BSACPA is discussed and analyzed sufficiently from the aspects of the theory,simulation and experiments,as given in following:(1)Several different brushless structures for the synchronous generator are compared and analyzed if they were employed in ACPA system.Then the motor/generator integrated BSACPA is also presented in this paper.(2)A novel inverse-sequence connective squirrel-cage rotor winding(SCRW)is proposed with its design procedures.The SCRW eliminates the four winding terminals of the conventional wound rotor winding,decreasing the winding resistance,shortening the axial length of the machine and increasing the power density.This topology can also be used in traditional ironcore cascaded doubly-fed induction motors.(3)The design processes and theory analysis of the BSACPA are presented in this paper,including the basic operation principle,power flow theory,electromagnetic field analysis method,steady-state equivalent circuit,transient formulas in dq reference,parameters calculation program,prototype design and optimization,prototype performance simulation,high-speed rotor dynamic simulation and strength check,and machine thermal simulation.They provide the guidance for the BSACPA design.(4)A motor/generator integrated BSACPA prototype and experiments are carried out in this paper.The experiments include the basic test and discharge experiments at low speeds.The experimental results are in good agreement with the simulation results,which verifies the operation principle of the BSACPA.