Research On Inductively Coupled Wireless Power And Data Composite Transfer Technology

Inductively coupled power transfer is widely used in electricial vehicles,implantable medical devices,consumer electronics,etc because of its advantages of small radiation,reliability,flexibility and no direct physical contact.In some occasions,in addition to realizing power transmission,a composite transmission of signals is also required to complete functions such as sending control commands,feeding back measurement signals,and monitoring system status information in real-time.While the existing wireless power and data transfer system mostly adopts separate channels to transmit power and data that will increase the system volume and complexity.At the same time,it generally uses low-order compensation which results in high circuit sensitivity and difficulty in implementing ZVS soft switching.In addition,there are few studies on the crosstalk between energy and signal transmission and the influence of higher harmonics of the energy transmission circuit on signal transmission.In view of the problems above,based on the traditional inductively coupled power transfer system,this paper proposes a composite transmission of power and data by sharing the same loosely coupled transformer without adding signal transmission coils and using high-order compensation network to ensure stable transmission of power.In this paper,the loosely coupled transformer is first modeled and simulated by Maxwell to determine its optimal parameters.To achieve power efficient and stable transmission,this paper explores the characteristics of the designed S/LCC compensation network with the method of fundamental impedance,including the static operating characteristics,input impedance characteristics,output characteristics and so on;Then amplitude shift keying is selected as the modulation method of the system.The impedance characteristics,signal transfer function,signal transmission noise ratio and signal transmission rate of each part of the signal transmission loop are analyzed.Besides,it also summarizes the main factors that determine the relevant characteristics.At the same time,the corresponding signal modulation and demodulation circuit are designed.Finally,the paper explores the comprehensive performance of the power and data composite transmission system,including an asymmetry processing of the compensation network to achieve MOSFET zero voltage soft switching,analysing the crosstalk between power transmission and data transmission.The influence ofthe higher harmonics of the inverter and rectifier components on power and signal transmission is also analyzed to verify that the designed system has good suppression performance for the two higher harmonics.At last,a prototype system is built.In the case of 10 cm air gap,under the power transmission circuit rated power of 50 W,the system efficiency reached 86.2%,and ZVS is realized.At the same time,the composite data transmission is realized.Under the ASK code "11001110",data transmission rate is 40 kbps,the signal to noise ratio is-3.01 d B which verifies the feasibility of the solution.