The New Portable Non-contact Charging System Research

Today, the portable electronic products have been widely used in people’s daily life. Each of them has an accompanying charger, Traditional charging method is basically a wired connection, this way there is the trouble of charging method, insecure, unsightly and other shortcomings. The new contactless charging method based on inductive coupling, can implement power transmission without any physical connection. Because of the advantages of safe, convenient, versatile, beautiful and durable, contactless charging has broad application prospects. However, it is not widely used because of the low efficiency and high cost. Therefore, studying of high-efficiency low-cost contactless charging system has certain significance. Some research based on contactless charging has done, the main contents of this article include the following aspects:Firstly, based on the mutual inductance model, separable transformer model has been built. Characteristics of four compensation mode of contractless power transmission are described in detail, including the voltage gain, impedance characteristics and the selection of compensation capacitor for primary and secondary winding. Simplify the system model and analysis under the conditions of the resonant state and the sine-wave input. It provides a theoretical basis for the circuit parameter design.Secondly, by comparison of the existing circuit structure, combined with the requirements of actual application, a kind of high-frequency inverter circuit has been designed with the structure of push-pull way. This circuit has lots of advantages, such as simply drove, small size, high efficiency, and so on. In order to ensure the primary and secondary coil work in the quasi-resonant state to improve transmission efficiency and achieve stability, a frequency of tracking system including Current transformer circuit, Phase compensation comparison circuit and Phase detector circuit was designed after analysis of the primary and secondary circuit.Thirdly, multi-layer PCB windings were studied in order to get uniform magnetic field in the plane on the basis of comparison and analysis of several designs of traditional coils. PCB windings were designed based on Simulation and Analysis.Finally, a contactless charging platform system was build for the test and analysis after a contactless charging prototype was designed with the rounded rectangle winding. Tested the charging system.