Research On Power Control Of Tram Without Catenary

Tram without catenary is a new type of urban rail transit vehicle,which has the advantages of large carrying capacity,low energy consumption,short engineering period and good comprehensive economy.It uses Wireless Power Transfer(WPT)technology to realize the transmission of electric energy from the grid to the rail train through electromagnetic coupling in a non-contact manner,solving the landscape and safety problems brought by the traditional overhead contact catenary.However,the wireless power transfer system is susceptible to its own parameters and environment,and the output power is constantly changing during the operation.To meet the power requirements of the vehicle,the output power of the wireless power transfer system must be controllable.Therefore,this thesis proposes a power control method for primary side constant current and secondary side power adjustment.On the basis of meeting the adjustable system power,the decoupling control of the primary and secondary sides is realized,and the feasibility of the control method is verified from the perspective of simulation and experiment.Based on the mutual inductance model,this thesis mathematically models and analyzes the wireless power transfer system without catenary.According to the structure of the system,the input-output relationship of the high-frequency inverter circuit,the resonant coupling circuit,the single-phase bridge uncontrolled rectifier circuit and the DC-DC conversion circuit is equivalent on the circuit.The function relationship between the equivalent load resistance of the system and the input resistance of the secondary side is derived.Emphasis is placed on the transmission efficiency and transmission power expression of the serial-type wireless energy transmission system topology The influence of the system equivalent load resistance,the mutual inductance between the system's primary and secondary coils and the system operating frequency on the transmission characteristics of the system are quantified.Secondly,according to the demand of energy management of the tram without catenary,the control strategy of the system output power is proposed.The dynamic characteristics of the system are analyzed.When the equivalent load of the system is increased,the primary current will rise sharply,which will affect the safety of the system.Therefore,the primary side adopts the phase shift control method to ensure the current is constant and the secondary side adopts the Boost circuit.The system equivalent power is changed by adjusting the duty ratio to realize the system power adjustment.According to the parameters of the tram without catenary,the simulation model of the system is built on MATLAB/Simulink,and the simulation results are analyzed to verify the effectiveness of the power control method of primary side constant current and secondary side power adjustment.Finally,the experimental platform of low-power wireless energy transmission system is designed and built.The design of primary circuit,coupling mechanism and secondary circuit are introduced respectively.The experimental platform is used for power control experiments to verify the control scheme proposed in this paper.,draw the conclusion of the experiment.