Wirless Charging Progress Presentation
- 1. Wireless Power Charging System Through Magnetic Induction Tamim Alkhonaini UBong Udoessien Nadeem Qandeel Advisor: Dr. Aiping Yao | Committee: Dr. Michael Glazos, Dr. Mark Petzold
- 2. Outline 1. Background 2. Problem Statement 3. Goals 4. Project Description 5. Modifications 6. Test/ Verification 7. Problems 8. Future Work 9. Budget 10.Conclusion
- 3. Background 1. 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.
- 4. 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.
- 5. Goals • First semester 1. Charge a mobile phone wirelessly through inductive coupling. 2. Using transmitter unit, reciever unit and Arduino. 3. Connect LCD and weight sensor. • Second semester 1. Establish communication between receiver and transmitter. 2. Ensure a 80% power transfer efficiency. 3. Base station will charge multiple mobile devices simultaneously.
- 6. Project Description ● Transmitter Unit (Base station). ● Receiver Unit. ● Control/ Communication Unit.
- 7. 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)
- 8. Project Description: Transmitter Unit LTSpice Simulation of Transmitter circuit.
- 9. 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.
- 10. 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)
- 11. 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.
- 12. 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.
- 13. 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 %
- 14. Test/Verification. Weight Sensor ● Sensitivity 10 g - 1 Kg ● Active area 4cm x 4cm
- 15. Test/Verification LCD ● Display phone information. LED’s ● Light indicators
- 16. 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
- 17. Test/Verification The Receiver circuit was designed and simulated by using LTspice.
- 18. 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.
- 19. 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.
- 20. Problems Transmitter Unit The ultimate goal of the Tx circuit is to achieve a high voltage and low current. Expected Outputs: 6V, 0.4A Experimental 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.
- 21. Problems Receiver Unit: The goal of the receiver circuit is to charge a phone. Expected Outputs: 4.8 V, 0.8 A Experimental 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.
- 22. 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.
- 23. Future Work • First semester modified schedule. • Second semester plan of work. Task Start Date Duration (Days) End Date First Semester Research 1/12/2015 34 2/15/2015 Proposal 1/20/2015 31 2/20/2015 Shopping 3/15/2015 15 4/1/2015 Design & Simulation 2/28/2015 5 3/5/2015 Parts Testing 3/3/2015 7 3/10/2015 Transmitter Testing 3/20/2015 30 4/19/2015 Receiver Testing 3/20/2015 30 4/19/2015 Arduino Testing 3/23/2015 23 4/15/2015 Transmitter & Receiver 4/20/2015 6 4/26/2015 Progress Report 4/21/2015 14 5/5/2015 Hardware Demo 4/27/2015 4 5/1/2015 Second Semester Transmitter & Receiver 9/5/2015 20 9/25/2015 Communication 9/15/2015 30 10/15/2015 Evaluation 10/20/2015 5 10/25/2015 Improvements 10/25/2015 31 11/25/2015 Final Hardware Demo 12/7/2015 3 12/10/2015 Final Report 11/20/2015 26 12/16/2015
- 24. Future Work GANTT Chart for both 1st and 2nd semester 1/12 2/1 2/21 3/13 4/2 4/22 5/12 6/1 6/21 7/11 7/31 8/20 9/9 9/2910/1911/811/2812/18 1/7 Research Shopping Parts Testing Receiver Testing Transmitter & Receiver Hardware Demo Transmitter & Receiver Evaluation Final Hardware Demo
- 25. Budget item Price per Unit Number of units Total 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
- 26. What’s learned! Based on research, simulation and experimentaion we learned about power conversion, system integration and requirements for wireless charging in mobile devices.
- 27. 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.