| The wireless power transmission is a kind of power transmission that useselectromagnetic wave to transmit energy, which can leave out the use of power cord andplug heads. The basic theory about wireless charging lithium battery combines with thewireless power transmission theory and lithium battery charging principle. The existingWireless Power Transmission theory is still continuously developing and perfecting.However, some companies and research institutions have made some wireless powersupply products in its familiar territory, but all these samples have the characteristicshortages of little power, short transmission distance, low transmission efficiency limit,has only applied in some special certain scene circumstances. Contrast to the immaturedevelopment of the wireless energy transfer theory, lithium battery charging principlehas been widely recognized, and have found such widespread use.This thesis introduces the basic principles of wireless charging the researchbackground and the wireless power transmission and lithium battery chargingtechnology and characteristics and completed the design of circuit simulation andhardware circuit. Performance test and the final results are given.This thesis introduces an electromagnetic induction wireless charger. It’s combinedwith magnetic coupling and switching power technology. The system can divide intowireless transmit part and receive part. Under the power supply of12V, the receivingend in2.5cm distance can stably output4.2V charging voltage, so as to realize thewireless charging lithium battery charging current adjustable and the transmitter circuitwith circuit protection function, which can effectively prevent the power MOS tube wasthe peak voltage breakdown, short circuit problem. At the receiving end in view of thecharacteristics of lithium battery charging design, effectively prevent the lithium batteryovercharge, may occur in the process of the temperature is too high, the current in adangerous situation. The whole circuit has simple structure, stable function; thereceiving end realizes miniaturization requirements, basically reached the level ofpractical application. |
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