Research On Wireless Charging Efficiency And Design Of Receiver Coil

With the development of the wireless charging market,the energy transmission efficiency between the wireless charging power transmitter and the power receiver has become a hot topic in the field of the wireless charging.As an important part of the wireless charging system,the receiver coil directly affects the wireless charging efficiency of the system.However,the design of the receiver coil has not yet been clearly defined in the industry rules and standards.For Wireless charging efficiency,in order to improve the efficiency of wireless charging system and enhance the practicability of receiver coil,this paper starts with three key factors:wire diameter,turn number and layer number of receiver coil to achieve higher efficiency of wireless charging.This paper starts with the analysis of the factors that affect the efficiency of wireless charging.The design requirement of the wireless charging test system is put forward,a set of wireless charging power transceiver is designed and implemented,the test data is analyzed,and the design strategy of the receiving end coil is given.The main contents of this paper are as follows:(1)The factors that affect the efficiency of wireless charging are analyzed.Combined with the basic principle of the wireless charging,a formula for calculating the efficiency(loss)of wireless charging system is established,and the calculation results of efficiency(loss)are obtained by deducing the formula.(2)The design requirements of wireless charging efficiency test system are put forward.The framework of the efficiency test system is set up.The design requirements of the basic composition of the wireless charging power transceiver,the specification of the coil,the specification of the shielding layer and the circuit are put forward,and the power transmission flow of the system is described.(3)Design and implement a set of wireless charging power transceiver.This paper analyzes the working principle of each part of wireless charging power transceiver and completes the selection of important components.The condition that LLC system works stably in ZVS is obtained by Mathcad calculation and measured waveform.The gain curves with and without C_s resonant capacitance are obtained by Mathcad modeling and Simplis simulation.By analyzing the gain curve,it is proved that it is necessary for the receiver to contain C_s resonant capacitance.(4)Analysing test data and the design strategy of receiver coil is put forward.Start with the three key factors:turn number,wire diameter and layer number of the receiving coil,several receiving coils required for the experiment are made,and the wireless charging efficiency test system and the self-built test environment are used.The charging efficiency of different receiving coils is measured accurately.The theoretical efficiency(loss)of different receiver coils is also obtained by theoretical calculation,which proves the consistency between the measured results and the theoretical calculations,and verifies that the proposed design strategy of the receiver coil can help to achieve higher charging efficiency.Select the coil which is the most efficient in the experiment test and the receiver coil of some mobile phone brand products to carry on the contrastive test.Under the test objects and conditions described in this paper,the efficiency of the coil design in this paper is high,which proves the effectiveness of the design strategy of the receiver coil proposed in this paper to improve the charging efficiency.Through the research,the efficiency of wireless charging system can be improved under the condition of considering the three key factors of the receiver coil diameter,turn number and layer number.