Theoretical Research And Design Of The AC Induction Exciter

Aiming at the shortage of the existing brushless excitation device, a novel AC variable frequency induction brushless excitation system is proposed, the AC induction exciter is the key component to increases strong excitation ability of the brushless excitation system, its performance calculation and design method is foundation of the design and optimization of the excitation system. this paper made a deep theoretical analysis on the excitation machine, and discussed its design method in detail.The basic equations and coordinate transformation principle of the AC induction exciter are introduced, according to mathematical model of AC induction exciter and rotating rectifier operating characteristics, the mathematical model of AC induction exciter is built in different coordinate system, The mathematical model which is suitable for the analysis of the control and output characteristics of exciter is obtained.Adopting the mathematical model in the rotor coordinate, three phase commutation state of the rotating rectifier operation is analyzed, and the external characteristic of the exciter and transfer function is derived, the relationship between the steady-state characteristics and frequency is analyzed.Two common silicon materials modeling methods are introduced, the variation rule of the different components of the constant coefficient three item iron loss model with the magnetic density and frequency is analyzed. the iron loss coefficient extraction method and steps of the Maxwell software is given, and the relationship between core loss and efficiency and frequency is analyzed.The program for the calculation of the size, the winding, the magnetic circuit, the parameters, the loss and the efficiency of the AC induction exciter is made, forming a computer analysis and design method of AC induction exciter, The calculation method of ANSYS Maxwell and its combined with external circuit simulation is introduced, and the detailed operation steps are given.The lamination size and winding arrangement of AC induction exciter is designed, the rated operating parameters of the AC induction exciter are calculated by the magnetic circuit method and the finite element method respectively, the influence on commutation overlap angle of different excitation winding resistance is analyzed, the power matching of the excitation winding and the AC induction exciter is studied, and the no-load characteristics of the original AC synchronous exciter are calculated and the different design schemes are compared.An experimental platform for the AC induction exciter is built, excitation experiment of static load test and rotating operation of exciter is completed, The stator voltage, current, rotor voltage and DC excitation voltage are recorded, and the experimental results verify the correctness of the theoretical calculation results.