05-11-2016, 11:42 AM
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Abstract:
The Near Field Communication (NFC) is an emerging technology in recent time. The NFC uses the principle of Mutual Induction for the communication between two devices. The two devices must be touched or the distance of separation should be less than 10cm. The current generation smartphones use NFC for sharing data. But sharing of power between two devices using NFC is what we try to explain in this paper. Concept of wireless power transfer has always been a fascination, but it could actually come true.
Introduction:
Smartphones are the most commonly found devices now a days. Everyone uses a smartphone and with the growing technology smartphones are becoming smarter and smarter. But every smartphone requires power to run and batteries are their lifeblood. But their batteries drain very fast, and people face a lot of trouble with a switched off phone. We have seen a group of people share their talk time in case of emergency. Similarly can a group of people share their battery power in case of emergency? To this day, such technology has not arrived. But this work visions at making this a reality.
Description:
The control switch decides which device receives the power and which device transmits the power in the operation.
Accordingly the AC to DC converter and inverters are selected for the operation. The DC signal from transmitting device is fed to a DC to AC converter which produces an AC signal, which will be then fed to the resonant coil in the circuit. Due to the alternating signal, magnetic field is set up. The receiving device’s coil which is in the vicinity of the magnetic field set up, due to mutual induction, produces alternating signal in the receiving device. This signal is fed to an AC to DC converter, in which steady state DC signal is produced. This DC signal then charges the receiving battery.
The time for which the power transfer takes place is as per user requirement.
Transmitter:
Transmitter is the part of the system which converts the DC power, from the battery, into AC power and excite the resonant coil. The circuit could be any oscillator, which produces oscillations at a frequency of 13.54MHz (standard NFC frequency). These oscillations are fed to the resonant circuit. When AC voltage is fed to the coil, fluctuating magnetic field is created. The field will be maximum at resonance.
The oscillator may be found in the form of Integrated Circuit(IC) or could be realized using analog components. But since this has to be implemented in a cell phone, IC is preferred over the latter. The resonant coil as in the figure [1] could be used.
Use of number coils increases the power transmitted, but it comes with a cost of higher power loss.
Receiver:
The receiver also has the same resonant coil in it. The coil when comes in the vicinity of the alternating magnetic field, current is produced according to Faraday’s law. Because the two coils are tuned at same frequency, maximum power is transferred to the receiving coil. The alternating current produced by the electromagnetic induction, is then converted to DC using rectification procedure. Prior to the rectification, if the current is very small, then introduce a current-boosting transistor before rectification. The rectifier uses a bridge circuit followed by regulator which helps to produce a constant voltage, DC voltage. This constant DC then would recharge the battery.
The realization of the transmitter and receiver on MultiSim11.0 are as shown in the figure [2]
Control Switch:
A control switch in this system, could be a system software of the cell phone. Assuming this to be an application, on either Android or iOS or on any other operating system, the control switch is defined. The function of the control switch is to determine the direction of flow of power. The user defines the direction of flow. The application also checks, if the energy in both devices’ cells are comparable. When they are comparable, the process of charging should stop.
Current Supplied by the coil is very less and hence charging may be slow.
The coil spacing should be specific. i.e. The coil should be held parallel to each other for it produce the desired output.
Conclusion:
The circuit regarding Charging of Cell phone battery is partially satisfactory as the amount of current produced by the coil is less and hence the charging time is very large. There is room for improvements in the coming days.
Abstract:
The Near Field Communication (NFC) is an emerging technology in recent time. The NFC uses the principle of Mutual Induction for the communication between two devices. The two devices must be touched or the distance of separation should be less than 10cm. The current generation smartphones use NFC for sharing data. But sharing of power between two devices using NFC is what we try to explain in this paper. Concept of wireless power transfer has always been a fascination, but it could actually come true.
Introduction:
Smartphones are the most commonly found devices now a days. Everyone uses a smartphone and with the growing technology smartphones are becoming smarter and smarter. But every smartphone requires power to run and batteries are their lifeblood. But their batteries drain very fast, and people face a lot of trouble with a switched off phone. We have seen a group of people share their talk time in case of emergency. Similarly can a group of people share their battery power in case of emergency? To this day, such technology has not arrived. But this work visions at making this a reality.
Description:
The control switch decides which device receives the power and which device transmits the power in the operation.
Accordingly the AC to DC converter and inverters are selected for the operation. The DC signal from transmitting device is fed to a DC to AC converter which produces an AC signal, which will be then fed to the resonant coil in the circuit. Due to the alternating signal, magnetic field is set up. The receiving device’s coil which is in the vicinity of the magnetic field set up, due to mutual induction, produces alternating signal in the receiving device. This signal is fed to an AC to DC converter, in which steady state DC signal is produced. This DC signal then charges the receiving battery.
The time for which the power transfer takes place is as per user requirement.
Transmitter:
Transmitter is the part of the system which converts the DC power, from the battery, into AC power and excite the resonant coil. The circuit could be any oscillator, which produces oscillations at a frequency of 13.54MHz (standard NFC frequency). These oscillations are fed to the resonant circuit. When AC voltage is fed to the coil, fluctuating magnetic field is created. The field will be maximum at resonance.
The oscillator may be found in the form of Integrated Circuit(IC) or could be realized using analog components. But since this has to be implemented in a cell phone, IC is preferred over the latter. The resonant coil as in the figure [1] could be used.
Use of number coils increases the power transmitted, but it comes with a cost of higher power loss.
Receiver:
The receiver also has the same resonant coil in it. The coil when comes in the vicinity of the alternating magnetic field, current is produced according to Faraday’s law. Because the two coils are tuned at same frequency, maximum power is transferred to the receiving coil. The alternating current produced by the electromagnetic induction, is then converted to DC using rectification procedure. Prior to the rectification, if the current is very small, then introduce a current-boosting transistor before rectification. The rectifier uses a bridge circuit followed by regulator which helps to produce a constant voltage, DC voltage. This constant DC then would recharge the battery.
The realization of the transmitter and receiver on MultiSim11.0 are as shown in the figure [2]
Control Switch:
A control switch in this system, could be a system software of the cell phone. Assuming this to be an application, on either Android or iOS or on any other operating system, the control switch is defined. The function of the control switch is to determine the direction of flow of power. The user defines the direction of flow. The application also checks, if the energy in both devices’ cells are comparable. When they are comparable, the process of charging should stop.
Current Supplied by the coil is very less and hence charging may be slow.
The coil spacing should be specific. i.e. The coil should be held parallel to each other for it produce the desired output.
Conclusion:
The circuit regarding Charging of Cell phone battery is partially satisfactory as the amount of current produced by the coil is less and hence the charging time is very large. There is room for improvements in the coming days.