Dynamic Wireless Power Transfer Technology for Maximum Power Transmission of Pre-Embedded Sensors Based on Optimization of Coil Parameters
In rail transit fields,pre-embedded sensors are crucial for structural health monitoring due to their low power consumption(tens to hundreds of milliwatts)and small size.Pre-embedded in the concrete of the subgrade,they can obtain the corresponding key status information in real-time to warn of the subgrade deformation,slope instability,bridge,tunnel damage,and other hazards promptly.Continuous and reliable power supply is the basic premise of the normal operation of the pre-embedded sensors.However,the battery life span is limited,and the wired power supply can easily be damaged.In contrast,the wireless power supply method is easy to install and redeploy,reducing the interference of the construction machinery operation,which provides a new idea for the pre-embedded sensor wireless reliable power supply.Using the inspection vehicle in its operation,the energy is radiated through the transmitting coil mounted on the bottom,and the receiving coil placed around the pre-embedded sensors along the railway line obtains the energy and stores it for the sensors.In the case of dynamic wireless power supply,the transmitter coils are mostly buried underground to supply power to the mobile devices carrying the receiver coils.However,these studies are mainly used for high-power electrical equipment,and the size of the receiving coil is comparable to that of the transmitting coil.At the same time,the shock characteristics of the transmitted energy during the movement of the inspection vehicle affect the smooth output,which is not applicable to the dynamic wireless power supply of pre-embedded sensors.The dynamic power supply is still in its infancy.This paper proposes a method for optimizing the transmitting coil parameters of a dynamic wireless energy transmission system based on equivalent power analysis.The energy acquired at the receiver is maximized,providing an effective solution for the reliable power supply of the pre-embedded sensors.The rebar structure is modeled,and the mutual inductance of the transmitting and receiving coils is obtained.The equivalent power is obtained,and the influence of the DD coil current direction and spacing is analyzed.Finally,an experimental prototype was built to verify the equivalent power calculation method of the proposed dynamic wireless power supply system.When the height difference is less than 220 mm,the DD coil with a different current direction and large coil spacing is good,and the spacing is optimal at 120 mm.When the height difference is more than 225 mm,the DD coil with the same current direction and small coil spacing is good,and the spacing is optimal at 0 mm.The optimized coil with a different current direction can obtain 0.14 W⋅s of energy,which is 50%higher than the pre-optimized coil with the same current direction.The experimental data during the optimization process agree with the theoretical analysis,which verifies the feasibility of the proposed method.
Pre-embedded sensorsdynamic wireless power transferparameter optimizationmaximum equivalent power
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