| With the wide application of implantable medical devices,the problem of energy supply has been given attention by many research groups at home and abroad.Magnetic coupling resonance wireless power transfer technology is widely used in the field of implantable medical devices.Because it has unique advantages in transmission efficiency and transmission distance.The size of the receiving coil is limited by the implantable medical device.It affects the transmission efficiency of the system.Therefore,improving transmission performance through the rational design of the coil is one of the most urgent problems to be solved.Firstly,the transmission mechanism of the magnetic coupling wireless power transfer technology is analyzed.The mathematical model of the system's circuit topology is established by an equivalent circuit theory.The transmission characteristics of the system are investigated.Several key factors that affect the transmission characteristics of the system are obtained.They are self-inductance of the coil,mutual inductance between the coils,frequency,and load resistance and so on.The impact of these key parameters on the transmission characteristics is analyzed.Secondly,an improved mutual inductance calculation method is proposed.The mutual inductance between the coils is computed by the finite element software.The experimental measurement platform of mutual inductance is set up.It is verified by the finite element method and experimental measurement.The solution of the finite element method,the theory method and the experimental measurement are coincident.Improved mutual inductance calculation method is used to calculate the mutual inductance of two coils in any relative spatial position.It is also suitable for different types of coils.Finally,the percutaneous wireless power transmission system is divided into two parts:the in-vitro transmitting circuit and the in-vivo receiving circuit.In the transmitter,the high-efficiency class E power amplifier is as an inverter circuit.In the receiver,the voltage double rectifier circuit is selected as the rectifier filter circuit.The type of resonant coil is optimized for the size limitations of the receiver in the body.A coil design method for increasing transmission efficiency is proposed.The results show that when the number of turns is determined,the single layer spiral coil is selected for the transmitting coil and the double plane helical coil for receiving coil.So that the transmission characteristics of the system is optimal.The transmission of wireless power under percutaneous conditions is achieved. |
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