| Wireless power transmission technology is an up-and-coming technology in the field of electrical engineering.It transfers energy by a wireless way,and solves the problems of line aging,point discharge,and electric spark during the traditional metal wire power transmission process.It is very suitable for wet,flammable,explosive and other extreme environments.Therefore,wireless power transmission technology will become the mainstream power supply solution in the future.Compared with other wireless transmission schemes,inductively coupled power transfer has the characteristics of large transmission power,high transmission efficiency,and easy influenced by distance.With proper coupler designing,the transmission can be completed under the premise of ensuring transmission power and transmission efficiency,also the impact of distance changes on energy transmission is effectively reduced.It is suitable for high-power,distance-changing wireless energy transmission.The research of this paper comes from an engineering project that the author participated in,in this project,the author is responsible for circuit debugging and coupler structure designing.The project needs to complete the 200 W power transmission task in the space of 200mm*200mm*100mm.The power supply end and the power receiving end are noncontact and guarantee the 15 mm range of motion.The project has strict requirements for the power supply environment.Through the analysis of project indicators,this paper achieves the project requirements.The main work of this paper is:(1)Analyze the project requirements,select the electromagnetic induction transmission scheme,and determine the topology of the transmission system,analyze the key links and parameters in the system,and provide guidance for the subsequent system design;(2)A more compact full-bridge inverter circuit with overcurrent protection is designed.The innovation of this circuit is that it eliminates the complicated overcurrent protection design of the traditional inverter,and uses the SG1825 chip with current limiting function as the inverter drive,which saves overcurrent detection and action circuit and other related components,saving circuit design.The chip usage and layout space,and the associated loss of the inverter are analyzed to ensure that the circuit power consumption meets the specifications;(3)A coupler with shaft structure is designed to solve the problem of serious fluctuation of coupling coefficient in dynamic distance transmission.The traditional coupler structure is often used for wireless energy transmission at a fixed distance.The coupling coefficient of the coupler cannot be dynamically adjusted with distance,which affects transmission stability.The project requires stable transmission of power under dynamic distance,and the traditional coupler structure cannot meet the demand.Through theoretical verification and MAXWELL software simulation test,the axial structure proposed in this paper effectively reduces the variation of the coupling coefficient under dynamic distance,thus ensuring transmission stability and transmission capability.In the system testing section of this paper,the feasibility verification of the shaft coupler is realized;(4)The shaft-coupled wireless energy transfer whole system is realized,and the system is tested experimentally.In the size of 200mm*200mm*100mm,the range of the coupler is 0~15mm,and the power input is 60 V.Energy source,complete 200 W power transmission,full load efficiency above 85%,verifying the feasibility of the shaft coupler.Finally,the shortcomings of the shaft-coupled wireless energy transfer system are summarized,and the future development of the system is prospected. |
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