Research On Multi-coil Magnetically Coupled Resonant Wireless Power Transmission System

The drawbacks of the traditional wired transmission method are gradually revealed,the wear,aging,etc of the wire are prone to lead to the touch sparks,seriously affect the reliability and safety of the power supply process.The magnetically coupled resonant transmission system has less electromagnetic pollution,high transmission efficiency,and does not cause harm to the human body,therefore,the technology has broad market application prospects.Firstly,the function relation of load receiving power and transmission efficiency with respect to transmission distance between coils in the multi-coil magnetic coupling resonant wireless power transmission system is theoretically derived in this paper.The influence of the relay coil position on the system performance is discussed by solving the non-linear equation which satisfies the constraints.In addition,the influence of the number of relay coils on system performance was analyzed.Based on the theoretical derivation,two kinds of platform software were designed.The software can simplify the complicated theoretical calculation,obtain the corresponding data directly according to the system parameters set in the practice,and the distance characteristic function of the system can be plotted.Based on the theoretical analysis of multi-coil magnetic coupling resonant wireless power transmission system,the experimental research was carried out by the experimental platform.The results show that in the multi-coil magnetic coupling resonant wireless power transmission system,the increase of the relay coils leads to the larger power and efficiency,but the improvement effect is only obvious when the transmission distance is long.In the three-coil magnetic coupling resonant wireless power transmission system,the transmission power is the largest when the relay coil is in the middle position,there is no obvious law in the four-coil system when the optimal transmission power is reached.In addition,the four-coil system can achieve a larger transmission distance than the three-coil system when the power of the load resistance is constant.Finally,in order to increase the power received at the load resistance,a power amplifier is designed at the front end of the transmitting coil,the double-coil,three-coil and four-coil systems are analyzed experimentally.The results show that the power amplifier can greatly increase the load receiving power,effectively extend the transmission distance of electric power,and enhance the system practicability.