Project
| # | Title | Team Members | TA | Documents | Sponsor |
|---|---|---|---|---|---|
| 66 | Inductive Charging Case Area Award: Power |
Anshil Bhansali Brian Slavin Jose Javier Rueda Montes |
Jackson Lenz | design_document0.pdf final_paper0.pdf presentation0.pptx proposal0.pdf |
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| Group Members: Anshil Bhansali - abhansa2 Brian Slavin - bmslavi2 José Javier Rueda - jjr3 Problem: As USB type C is becoming more common in phones, many companies are getting rid of the headphone jack on phones. This creates a big problem for those who want to transfer data or listen to music while charging their phone. Solution: Our idea is to implement a Qi transmitter circuit into a case along with a rechargeable battery (It would probably be under 2000mah in order to keep the thickness of the case down). The main components of the transmitting circuit would fit on a PCB board, with the coil attached at the end of the board. It would also be helpful for the user to enable software to turn off charging directly from the phone and to view charging statistics via an app. The main problem would be the distance between the coil in the phone and the coil in the case. The charging distance is usually 6-8mm, so we would have to account for this in the case design. Modules: DC-AC: The most important module is the DC-AC circuit. This will take in a DC current coming from the battery and convert it into an AC current that can be sent through a coil (with specified dimensions and thickness). The major difficulty in implementing this is that Qi doesn’t operate on a single frequency but rather many and the current must constantly change. The microcontroller for this module communicates with a controller on the receiver circuit inside of the phone and makes corrections to attain the necessary frequency. Coil: The coil itself must be taken into consideration when considering the design side of things. There are many configurations of coils with some designs using three layered on top of each other for maximum coverage. We plan on using a single coil design in order to save space. Wifi Module (Or Software): We will either implement a wifi component to the circuit in order to receive data directly from the circuit (and be able to turn it on and off) or simply use software on the phone in order to analyze charging speed, efficiency, etc. for the user end of things. Voltage Stabilizer: We will need to implement a DC-DC circuit (possibly a step up circuit based around what battery is chosen) in order to ensure that the DC-AC circuit always has a constant voltage. Receiving Circuit: The final module would be to add in a receiving circuit identical to that inside of the phone on the opposite end of the case. By doing this, we can essentially enable wireless charging for the case itself. Requirements/Verifications: We want to obtain a minimum efficiency of around 70-75% as this would give the phone a battery life of 150% (We intend to use a smaller battery than that of the phone). This can be tested directly with software as we can calculate how much mah has been transferred and we will know the exact capacity of our battery. In terms of voltage stability, we would like to see no more than a .1V shift in voltage in the DC-DC circuit. This is more so conducive to the upper limit as anything over 5.1V could potentially damage the circuit, especially in the long term. We will have to test this separately as a module before attaching it to the DC-AC circuit. Obviously, we need to verify that the case actually charges a phone, but I’m more curious to analyze the effects of charging a phone while the case is being charged simultaneously. I would also like to test the cases charging each other with no phone involved. |
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