Research On Load Power Feedforward Closed Loop Control Of Contactless Excitation Energy Transmission System

At present,metal wire connection is often used in the most of the synchronous motor excitation system energy transmission.This kind of connection makes many shortcomings,such as some safety problems caused by bare wire.Furthermore,it could not satisfy the special needs,such as the electric vehicles,medical and other fields of energy transmission of.In order to overcome many of the traditional ways of energy transmission,contactless energy transmission technology will also be proposed.Because of the existence of the brush in the excitation synchronous motor,it not only affects the stability of the system,but also increases the failure rate of the excitation synchronous motor.So it is inevitable for the excitation system of the vehicle to realize the brushless.There are more or less shortcomings and problems in the technology of synchronous motor brushless excitation both here and abroad.Such as the complexity of the structure,the additional magnetic field,the difficulty of adjusting the main magnetic field and so on.The contactless synchronous motor rotor excitation control system,which is analyzed in this dissertation,is suitable for both synchronous motor and synchronous generator.On the one hand,the brush of the excitation system is omitted.On the other hand,some shortcomings of the brushless synchronous motor are improved.Therefore the efficiency and power factor of the motor are significantly improved.This dissertation discusses the composition of the contactless excitation energy transmission system and the working principle of the contactless synchronous motor rotor excitation system.Then it analyzes the characteristics of the contactless tank transformer.In view of the large leakage inductance,the mutual inductance model is selected to simplify the equivalent circuit of the contactless transformer.By analyzing the characteristics of the mapping impedance and the power transmission in the resonant compensation network,the leakage inductance is compensated by the series-series compensation structure.The mathematical model of the transformer both before and after compensation is established and simulated by MATLAB/Simulink.Through this the simulation waveform of the original side voltage,secondary side voltage and secondary side current of the transformer both before and after compensation can be obtained.By comparing the waveforms before and after compensation,it is proved that the series-series compensation structure can compensate the leakage sense very well.In order to not only improve the output characteristics and the stability of the system but also enhance the capacity of resisting disturbance of the system,the algorithm of the load power feedforward is proposed.First,the simplified circuit model can be observed through analysis.Then,the dynamic equation is established to analyze the algorithm of the load power feedforward of.The simulation model is built by Saber2012 to compare the simulation waveform of the DC output under the open loop,PI closed loop control and the load power feedforward control.The theory of the load power feedforward control algorithm is verified.Finally,an experimental platform for the contactless synchronous motor rotor excitation system is built.The output characteristics of the system are analyzed experimentally to verify the correctness of the proposed method and simulation results.