Design And Implementation Of Transmission Efficiency Test System For Loosely Coupled Transformer

Inductively coupled power transfer technology can achieve the non-electrical transmission of electricity,and fundamentally avoid the potential safety hazard caused by short circuit of power spark and power supply circuit.Loose coupled transformer is the core power components of inductively coupled power transmission system.Due to the load,volume and weight of the system,many parameters of the loosely coupled transformer are limited,making frequency the only variable factor that can optimize system efficiency.Therefore,designing a transmission efficiency test system that capable of continuously adjusting frequency and meeting the demands of voltage,which has great significance for maximizing the efficiency of the inductively coupled power transfer system.Firstly,the structure and working principle of the inductively coupled power transfer system are be analyzed.The mutual inductance equivalent circuit model of loosely coupled transformer is established and the relationship between transmission efficiency and frequency is derived.Based on the requirement of the transmission efficiency test system of the loosely coupled transformer,the working principle of the power amplifier circuit in the system is analyzed.The frequency characteristics of the high-frequency transformer,the voltage decay and distortion occurring in the high and low frequency bands are simulated.Secondly,the main circuit system of transmission efficiency test system is designed,including high-power adjustable voltage regulator,power amplifier and protection circuit.Multisim circuit simulation software is applied to the main circuit system for temperature scanning,AC analysis and load characteristic testing.Then,the high-frequency step-up transformer has been designed and calculated in detail,including the choice of core material,determining the core structure and model with minimum loss;The size of the core window is optimized,and the loss characteristics and core saturation of the transformer are analyzed by COMSOL finite element simulation software.Aiming at the voltage decay occurring in the process of frequency change,a method of changing the turns ratio in different frequency bands is proposed,which makes the voltage almost without distortion in the frequency range required by the subject.the power amplifier circuit matched with the high-frequency step-up transformer is designed,and verify that the system can achieve constant voltage output with purely resistive and resistive load in the COMSOL,and achieve the coordinated control of the sub-bands by using the optocoupler to control the on-off of the DC voltage.Finally,the experimental prototype of the transmission efficiency test system for loosely coupled transformers is developed,and the output performance and load carrying capacity of the power amplifier circuit and the entire system are experimentally tested.A measurement method for the transmission efficiency of the loosely coupled transformer is proposed.The primary and secondary power,the maximum transmission efficiency and the corresponding optimal operating frequency of the loosely coupled transformer are determined,the research results in this paper can provide some theoretical and practical guidance for maximizing the efficiency of inductively coupled power transfer system.