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With advances in technology and lower cost electronic components, mobile phones have become essential in our daily life communication tools, at the same time, cars are approached our lives, showing civilians trend. People in long-distance travel or business trip, if the phone battery runs out, it will have a huge impact on people's normal work and life. Now part of the car has appeared in both car charger car phone charger wireless, but due to different brands of mobile phone charging interface are very different, so if you want to be recharged in the car and you must bring your own cell phone charging matches It is not very convenient. And because the vehicle power supply is limited and does not allow multiple phones simultaneously charging. Based on the above, we propose the idea of vehicle wireless charger, the electromagnetic induction technology into the field of mobile phone charging by electric, magnetic, magneto-electric conversion, a non-contact charging of the phone, which is similar to the core technology of coreless transformer treatment.
2, the idea of wireless charging
2.1 The overall plan diagram
This paper presents a vehicle for a new mobile phone charging solutions, and system hardware block diagram in Figure 1 and are shown in Figure 2.
Car Wireless Charger
Car cigarette lighter 12V Dc-550 rrA provide power using an inverter to inverter to mains, the built-in induction coil connected to the base of the inverter output. Because the square spiral indiscriminately into the adjoining edge of the connecting portion, the presence of the current mutation. Therefore, using the built-in induction coil radius circular spiral coil of 5cm.
Phone receiving end receiver module and primary phone charging circuit. Will receive an induction coil, rectifier, filter circuit through the PCB technology integration in sufficiently small module, built-in cell phone batteries, the receiver module output to a 5V DC 1A. Provide power for mobile phone battery, thereby completing the wireless charging capabilities.
3, wireless charging works and its parameters
Wireless charging the charger and the receiver and asked the current is no direct link, coil current, voltage is generated by a magnetic coupling, and its essence is a pair of mutual coupling coil, magnet coils no substance, the equivalent circuit diagram shown in Figure 3 It shows:
4, the inner coil 1 and the coil 2 are located at the base and handset receiving module, assuming that the coil 1 (number of turns. ") Current is passed through, the line ignored the magnetization 2 (number of turns) at It can be approximated as:
2 is the magnetic flux of the coil:
2 stars coil induced electromotive force is:
So, simply adjust the turns ratio of the two coils of the transformer can play a role in the simultaneous wireless transmission to give the desired phone charging voltage.
Since the receiver module in the induction coil sensed alternating current, in order to meet the requirements of mobile phone charger, must also join the rectifier and filter circuit in the receiver module.
In this paper, the use of electromagnetic induction technology for wireless mobile phone charger study. So that the charger can charge the battery in the absence of direct contact of the current situation. And can be provided within a multi-car phone charging service, convenient and economical, if used in bathrooms and other damp environment, its safety performance is shown. Therefore, the wireless charger will have extensive research and practical value.