Research On Resonant Omnidirectional Wireless Power Transfer System

With the increasing popularity of portable consumer electronics equipment,consumer electronics equipment has more and more charging demand.The wireless power transfer system composed of weak coupling coils is a very promising charging solution.Because it does not need a wire and has great convenience,it is becoming increasingly popular at the consumer electronics equipment charging technology center.So far,the widely used wireless charging system on the market mainly adopts a flat structure,and the magnetic field stimulated by the launch coil is one-way.When the device receives a certain bias distance and angle between the device receiving coil and the launch coil,the power transmission capacity and transmission efficiency will be greatly low.In order to improve the flexibility of the charging system of the wireless power transfer system,this article proposes a rectangular coil structure without cover,without requiring the receiving coil and the launch coil.Regardless of how to place the receiving coil,there will always be a transmission path for transmitting coils and receiving coils to provide energy transmission paths.Through ANSYS Maxwell,the launch coil structure is optimized and optimized to determine the structural parameters and electrical parameters of the launch coil.In order to improve the power transmission capacity and transmission efficiency of the omnidirectional wireless power transfer system,the compensation circuit usually uses compensation and adjustment to the system.The resonant circuit consisting of weak coupling coils and compensation circuits is important to design with omnidirectional wireless power transfer system.In this system,the coupling coefficient between the transmitting coil and the receiving coil is determined by the position.Change coupling working conditions are a difficult point for the selection of resonance topology.For the omnidirectional radio energy transmission system,the following conditions must be met:(1)the resonance frequency has nothing to do with the coupling coefficient;(2)the output voltage has nothing to do with the load;(3)The current of the transmitting coil has nothing to do with the load and coupling coefficient;(4)the input impedance is emotional,and the ZVS soft switching function is realized.In addition,the circuit should also achieve as high transmission efficiency and transmission capacity as possible.In order to meet the above requirements,the launch side selects parallel resonance,and the receiving side is selected in series resonance,and the circuit is simulated to verify the circuit.In consumer electronics applications,the improvement of working frequency can improve the power transmission capacity and transmission efficiency of wireless power transfer systems.This article selects the "Air Fuel" standard with an operating frequency of 6.78 MHz.In the MHz system,the switching device to achieve soft switching operations can help reduce the problem of switching loss and electromagnetic interference.Therefore,the theoretical design and analysis of the system soft switch was finally verified by the LTspice simulation.