| Based on the principle of electromagnetic induction,the Magnetic Coupling Wireless Power Transfer(MC-WPT)technology realizes the Wireless transmission of complete electrical isolation through alternating electromagnetic field,which has broad scientific research value and practical application prospect.This paper to the radio can transmit topology as the research object,the second by second port theory,briefly expounds the current application more low compensation topology and the output characteristics of the high order compensation topology,finally through to the two kinds of secondary side S compensation topology for the impedance model analysis,made clear the aim of this article for the LCC-S compensation topology,In addition,an in-depth study was carried out on the problems of resonant compensation network parameter configuration difficulty,high-order nonlinear output characteristics,complex control and high cost of LCC-S MCWPT system.The contents are as follows:(1)Topology analysis of MC-WPT system.By combining the traditional compensation topology and high-order compensation topology of MC-WPT system with the two-port equivalent theory,the advantages and disadvantages of the current compensation topology are analyzed and briefly expounded.According to the application requirements of the current MC-WPT system,the output characteristics of the primary side constant current and secondary side constant voltage presented by the LCC-S topology are analyzed.The research object is LCC-S MC-WPT system.(2)Parametric nonlinear programming of resonant compensation network in full resonant mode for LCC-S MC-WPT system.When the resonant compensation of LCC-S topology is studied,it is found that the parameter configuration of the primary side series compensation inductor in full resonant mode is free,and it only needs to be less than the transmitting coil.Therefore,a parameter planning method is proposed to obtain the most suitable resonant compensation network parameters by comparing the output characteristics of the system,so that the output power of the system can meet the requirements and improve the transmission efficiency.The result of the planning is used as the compensation network parameter configuration of the LATER MC-WPT system.(3)Study on constant current frequency domain of LCC-S MC-WPT system.By using variable substitution method and without adding any components,the working frequency domain which can make the output characteristic of the system change from constant voltage to constant current is derived,and the correctness of the theory is verified by simulation.By comparing and analyzing the inverter current THD value,output power and transmission efficiency of the constant current frequency domain detuning mode and full resonance mode system,it is concluded that the MC-WPT system in constant current frequency domain is characterized by high power and low efficiency,which is suitable for high power work scenes such as rescue and disaster relief,underground coal mine.The full resonant mode MC-WPT system is characterized by high efficiency and low power and is suitable for most radio transmission applications.Aiming at the low efficiency of LCC-S MC-WPT system in constant current frequency domain,ac-AC AC envelope modulation technology was introduced to reduce the system cost and control difficulty,and improve the transmission efficiency of the system.A real object was built for experimental verification,and the results show that the theoretical research in this paper is effective.(4)Constant voltage charge control,constant current charge control and constant current/constant voltage two-stage charge control of LCC-S MC-WPT system.On the basis of the parameter planning above,aiming at the charging method of ev that is most widely used at present,a four-switch Buck-Boost converter is added after the rectifying bridge on the secondary side to realize constant voltage charging,constant current charging and constant current/constant voltage two-stage charging of the whole charging system.The simulation results show that the three control systems designed are effective.The constant voltage control system can output constant voltage stably and has certain anticoupling offset ability.Constant current control system can not be affected by the load to provide a stable output current and simple control,high precision;The constantcurrent/constant-voltage two-stage control system combines the constant-voltage control and constant-current control designed before,simplifying the difficulty of control and ensuring that the charging process strictly follows the rigid requirements of first constantcurrent and then constant-voltage.Moreover,the charging voltage and charging point current almost have no fluctuation,and the system has high precision. |
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