Research On Dynamic Wireless Charging System Of Mobile Equipment With Buffered Super Capacitor

Mobile equipment power supply and energy storage have become the key to solve energy crisis,reduce environmental pollution,and improve the quality of life and production.At present,the power source of mobile vehicle and other mobile devices is mainly from battery,however,shortcomings of the existing battery and charging technology such as short battery life,long charging time,and low charging efficiency restrict the development of mobile devices.Super capacitor is expected to replace the dominant position of battery on energy storage field in the future,because of its high charge and discharge power,long cycle life and other advantages.With the rapid development of power electronic technology and semiconductor devices,wireless power transfer(WPT)technology has been widely studied and applied.WPT can achieve transmission of energy without cable,when high transmission efficiency,high power,farther transmission distance and others are achieved.And the pickup can move flexibly,and it is suitable for mobile applications in charging occasions.Dynamic Wireless Charging(DWC)technology is an emerging technology based on the principle of electromagnetic induction WPT.With DWC technology,mobile device in the power supply rail coil area can be dynamically charged by electromagnetic induction.DWC overcomes the problems that battery life is short,endurance is weak,charging time is long and other shortcomings to a certain extent.The invention of super capacitor,the mature application of WPT technology have brought hope to solve the problem of energy storage and mobile device power supply.Research on DWC is expanded mainly from the following aspects:(1)The initial design for DWC system.The basic structure of the system charging circuit is determined via comparison and analysis of DWC characteristics.In order to maximize the picked energy in the process of moving charging,and to avoid the introduction of control in the pickup,super capacitor is used as the system load,playing the role of energy caching.(2)Using the Laplacian phasor transformation,the process of start-up of charging process is analyzed,and the dynamic model of the coil current change process of the DWC system with super capacitor load is obtained.The model is validated by theoretical analysis and simulation.(3)Using mechanism modeling to model the mobile charging process of mobile device in power supply track,the dual input dual output transfer function model of the system is obtained.And decoupling condition of the system and the complex frequency domain expression of the coil current under the decoupling condition are obtained by analysis.Finally the variation of operating frequency,resonant current,system efficiency and power with input voltage are studied.(4)DWC system power circuit and signal circuit design.The control of the track current is realized by using the segmented hysteresis loop control method.The condition of realizing the zero voltage switch(ZVS)of the resonant converter and the failure condition of ZVS are analyzed.An experiment device was built and the correctness of the theoretical analysis and simulation was verified by experimental means.