| Magnetic Coupled Wireless Power Transfer(MC-WPT)technology is one of the most mature and widely used Wireless Power Transfer(WPT)technology.It uses highfrequency electromagnetic field as the transmission medium and transfers energy from the transmitter to the receiver.It can effectively solve the equipment power supply problem in special power applications.It has the advantages of security and flexibility.In some special applications,MC-WPT system will also face wide input voltage range,large load fluctuation and large change of coupling distance.In such application scenarios,the system may not be able to maintain constant voltage output to provide stable power to the load.Therefore,this paper will study this situation,the main works are as follows:(1)The advantages and disadvantages of the constant voltage output technology commonly used in MC-WPT system and its constant voltage adjustment ability when facing the above factors are analyzed.Then,the influence of typical key technologies such as high frequency inverter circuit,DC-DC converter circuit and resonance compensation network on MC-WPT system and their application occasions are analyzed.Finally,the voltage regulation method of cascade Boost converter with phase-shifting control full bridge inverter at the transmitter end of the system and the scheme of LCC-S resonant compensation network are presented.(2)AC impedance modeling and analysis are carried out for the transmission characteristics of LCC-S type resonant compensation network,and the influence of load,mutual inductance and input voltage on the output voltage of LCC-S type MC-WPT system is studied.On this basis,the mathematical model of Boost converter circuit under non-ideal continuous operation mode is established by using three-port switch device model method and energy conservation method,and then the exact mathematical model of LCC-S MC-WPT system is established by using generalized state space averaging method.(3)A detailed analysis of the key features of the power MOSFET devices is presented.Based on the law of conservation of energy,the calculation methods of loss and efficiency for each link of the system are given.,and the theoretical transmission efficiency of the system in phase-shifting mode and boost mode is calculated for different coupling distances.Then,according to the established system mathematical model,and combined with the actual needs,the closed-loop controllers of the system are designed in the phase-shifting mode and the boost mode respectively.Finally,the closed-loop control system is simulated by using MATLAB/Simulink.(4)The validity and practicability of the constant voltage output MC-WPT system proposed in this paper are verified by experiments.The experimental results show that the system can maintain constant voltage output under load fluctuation,coupling distance change and wide input voltage range. |
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