Contactless Energy Transmission Brushless Electrically Excited Synchronous Generator

The electric excitation synchronous generator has superior excitation regulation characteristics and fast de-excitation capability under faults,and its operational reliability is much better than that of permanent magnet generators,so it is widely used in the field of on-board power generation systems with high reliability requirements.In order to overcome the potential safety hazard of sparks caused by carbon brushes and slip rings,a type of rotating armature brushless exciter system is common in excitation application,but its complex structure,large volume,high cost and slow dynamic response limit its application in the special vehicles.In addition,the on-board generator system adopts three-phase four-wire for power supply,which requires high quality of phase voltage waveform and is sensitive to volume and weight.Therefore,optimizing the waveform of generator phase voltage and designing a brushless excitation device with high efficiency,high power density and excellent dynamic characteristics have high application value in the field of vehicle power generation.This paper focuses on the optimization of the voltage waveform of a Y-N connected brushless excitation generator and a brushless excitation system which is based on high-frequency rotary transformer with soft ferrite core.Firstly,based on the optimization of generator pole shoe and sinusoidal winding design,the matching design of the damper winding position parameters is deeply analyzed.The analytical expressions of induced electromotive force and magneto-motive force of damper winding are derived,and the analytical calculation model of harmonic suppression effect of the damper winding on stator armature magneto-motive force is established.Based on this design,the damper winding structure is optimized and the prototype is developed.The simulation and experimental results prove the correctness of the proposed method for analyzing the magneto-motive force of damper winding,which provides a theoretical basis for the optimal design of damper winding of generator.Secondly,in oeder to overcome the shortcomings of the conventional brushless exciter in vehicle applications,this paper introduces a new brushless excitation device based on high-frequency rotary transformer structure with soft ferrite core.By establishing 3D finite-element field-circuit coupling model of rotary transformer,the influence of winding,air gap,coupling coefficient,load and compensation on the working characteristics of the rotary transformer is analyzed.Based on Simulink,the mathematical simulation model of the resonant circuit is established.The frequency characteristics of the resonant circuit are simulated and analyzed,which provides a basis for the selection of resonant circuit parameters.Finally,based on ARM embedded system,this paper designs a high-frequency resonant full-bridge phase-shifting inverter circuit and full-bridge rotary rectifier circuit to realize the control of brushless excitation system of the generator.The prototype experiment of the rotary transformer and its control system has proved that the contactless energy transfer device designed and developed in this paper has good performance and high practical application value.