Transcript
Wireless Power Charging System Through Magnetic Induction
Tamim AlkhonainiUBong UdoessienNadeem Qandeel
Advisor: Dr. Aiping Yao | Committee: Dr. Michael Glazos, Dr. Mark Petzold
Outline1. Background2. Problem Statement3. Goals4. Project Description5. Modifications6. Test/ Verification7. Problems8. Future Work9. Budget10.Conclusion
Background1. Wireless energy transfer since 1800’s.2. Interest in new applications for consumer
products. 3. Applications could extend to higher power, e.g.
electric vehicles.4. Industry standard which all products conform
to.5. Wireless Power Consortium; Qi Standard.6. Different devices will charge with each others
wireless charging device.
Problem Statement
Design and implement a wireless phone charging system, in compliance with Qi standard, that will transfer around 5W of power to a mobile device, using inductive coupling.
Goals• First semester1. Charge a mobile phone wirelessly through inductive coupling.2. Using transmitter unit, reciever unit and Arduino. 3. Connect LCD and weight sensor.
• Second semester1. Establish communication between receiver and transmitter. 2. Ensure a 80% power transfer efficiency. 3. Base station will charge multiple mobile devices simultaneously.
Project Description● Transmitter Unit (Base station).● Receiver Unit.● Control/ Communication Unit.
Project Description: Transmitter Unit
● Step Down Transformer○ 240V/12v
● Half Bridge Inverter: Converts DC to AC ○ 12V VDD○ 5V, (110 KHz - 205 Khz), 50% Duty Cycle○ 2N7002 Mosfets (2)
● Resonant Circuit: Converts AC square wave to sinusoidal wave○ Primary Coil (12.5uH)○ Capacitor (0.147uC)
Project Description: Transmitter Unit
LTSpice Simulation of Transmitter circuit.
Project Description: Receiver Unit The receiver unit is responsible for picking up AC signal from the transmitter unit using secondary coils, and then convert it to DC voltage to charge the phone.
Project Description: Receiver Unit Receiver unit consists of:● Resonant Circuit: AC filter. ( L = 16 uH, Cs=127 nF, Cd= 1.6 nF)● Full bridge rectifier: convert from AC to DC. (Four 1N4148
diodes) ● Low-pass filtering capacitance: 22uF● voltage regulator: regulate voltage to 5 V. (LM7805C)
Project Description: Control /Communication Unit
Arduino Uno● Control switching frequency of system using PWM.● Control LCD output.● Receives input from weight sensor.
Communication● Send instructions from receiver to transmitter regarding:
o Start and stop charging.o Amount of power supplied.
Modifications● Transmitter circuit
○ Use of half Bridge Inverter ○ Half bridge Driver IC to maximize switching speed.
● Receiver circuit○ Add resonant capacitor to have a stronger signal which will
increase the efficiency. ● Communication and Control
○ NFC as an alternative to Bluetooth.○ Automatic connection (No Pairing). ○ Tag doesn't require Power.○ 2 PWM’s instead of 4.○ Use less than 4 buttons for LCD.
Test/Verification
Generation of PWM signal● Desired frequency range 100 KHz - 200 KHz
(recommended 125 KHz)● Duty cycle range (0%<d<100%) ● Amplitude 4. 7 V● Noise 0.5-0.9 %
Test/Verification.
Weight Sensor● Sensitivity 10 g - 1 Kg● Active area 4cm x 4cm
Test/Verification
LCD ● Display phone information.
LED’s● Light indicators
Test/Verification
Testing Results (Receiver unit):A phone was tested while it is charging to measure the exact charging voltage and current. ● Phone type: iphone 4s● Voltage: 4.75 V● Current: 0.77 A● Power: 3.66 W
Test/Verification
The Receiver circuit was designed and simulated by using LTspice.
Test/Verification
LED experiment was done to test the magnetic induction between primary and secondary coils. ● Using a function generator, the primary coil was supplied by:
120 KHz sine wave, 8 Vpp. ● 120 KHz → weak light , 230 KHz → strong light.
Test/Verification
Transmitter unit: ● Load Voltage: 2.4V,50% Duty cycle,
110 Khz.● Load current: 0.16A.● Load Resistor: 15 Ohms.● Dimly lit LED, No coupling.
ProblemsTransmitter UnitThe ultimate goal of the Tx circuit is to achieve a high voltage and low current. Expected Outputs: 6V, 0.4AExperimental Outputs: 2.4V at 50% duty cycle.
● Cross Conduction● Slow switching due to CMOS inverter low current.
Some Problems.
Possible Solutions.● Use a half-bridge driver ic.
ProblemsReceiver Unit:The goal of the receiver circuit is to charge a phone. Expected Outputs: 4.8 V, 0.8 AExperimental Outputs: 4.70 V, 0.047 A
● output current is very low <0.05 A● Secondary coil can not pick up a signal from transmitter unit.
Some Problems:
Possible Solutions:● Use a transistor as a current
amplifier.
Future Work
● Addition of NFC Reader and Tag to transmitter and receiver unit respectively.
● Improve circuitry for both transmitter and receiver.
● Use PWM generated from UNO to run transmitter circuit.
● Producing a document comparing research and findings.
Future Work
• First semester modified schedule.
• Second semester plan of work.
Task Start Date Duration (Days) End DateFirst Semester
Research 1/12/2015 34 2/15/2015Proposal 1/20/2015 31 2/20/2015Shopping 3/15/2015 15 4/1/2015
Design & Simulation 2/28/2015 5 3/5/2015Parts Testing 3/3/2015 7 3/10/2015
Transmitter Testing 3/20/2015 30 4/19/2015Receiver Testing 3/20/2015 30 4/19/2015Arduino Testing 3/23/2015 23 4/15/2015
Transmitter & Receiver 4/20/2015 6 4/26/2015Progress Report 4/21/2015 14 5/5/2015Hardware Demo 4/27/2015 4 5/1/2015
Second SemesterTransmitter & Receiver 9/5/2015 20 9/25/2015
Communication 9/15/2015 30 10/15/2015Evaluation 10/20/2015 5 10/25/2015
Improvements 10/25/2015 31 11/25/2015Final Hardware Demo 12/7/2015 3 12/10/2015
Final Report 11/20/2015 26 12/16/2015
Future WorkGANTT Chart for both 1st and 2nd semester
Research
Shopping
Parts Testing
Receiver Testing
Transmitter & Receiver
Hardware Demo
Transmitter & Receiver
Evaluation
Final Hardware Demo
Budgetitem Price per Unit Number of
unitsTotal price
LCD Display Board
$ 20.00 1 $ 20.00
Transmitter Coils $ 10.00 1 $ 10.00
Receiver Coils $ 8.00 1 $ 8.00
Arduino $ 30.00 1 $ 30.00
Bluetooth Module $ 35.00 1 $ 35.00
Sensor $ 4.00 1 $ 4.00
USB breakout $ 10.00 1 $ 10.00
Shipping $ 30.00
1st semester total cost is $ 147.00
item Price per unit
Number of units
Total price
Sensors $ 4.00 3 $ 12.00
Transmitter Coils
$ 10.00 3 $ 30.00
Receiver Coils
$ 8.00 1 $ 8.00
Shipping $ 30.00
2nd semester total cost is $ 80.00
What’s learned!
Based on research, simulation and experimentaion we learned about power conversion, system integration and requirements for wireless charging in mobile devices.
Conclusion
Modifications to the project based on new information about Qi standard and problems encountered, will lead to improvements in the design and circuitry of the project. This will allow for efficient power transfer and communication between the base station and a mobile device.
top related