Development of a Wireless Power Transmission System - Electrical Engineering Guide
1. Introduction
Wireless Power Transmission (WPT) refers to the transmission of electrical energy without wires or physical connectors. It allows powering or charging devices remotely using electromagnetic fields. WPT is increasingly used in consumer electronics, electric vehicles, and medical implants.
2. Objectives
• Design and implement a prototype for wireless power
transmission.
• Explore resonant inductive coupling as the transfer method.
• Test efficiency, range, and effectiveness under different conditions.
3. System Overview
The WPT system consists of a power source, a transmitting coil, a receiving coil, and an energy harvesting circuit. The transmitter converts AC power into a magnetic field, which is received and converted back to electrical energy.
4. Working Principle of Wireless Power Transmission
WPT works on the principle of electromagnetic induction or magnetic resonance coupling. An AC current passed through a coil generates a magnetic field. A nearby coil resonates at the same frequency to receive the energy wirelessly.
5. Types of Wireless Power Transmission
• Inductive Coupling
• Resonant Inductive Coupling
• Capacitive Coupling
• Microwave Transmission
• Laser Transmission
6. Components Required
• High-frequency oscillator circuit
• Transmitting coil (copper wire)
• Receiving coil
• Capacitors for resonance tuning
• Rectifier and voltage regulator (LM317 or similar)
• Power supply unit (12V DC)
• Load (LEDs, battery, or phone charger)
7. Circuit Diagram and Design
The circuit includes a high-frequency generator, tank circuit for tuning, and a rectifier on the receiving end. Both coils are tuned to the same resonant frequency for maximum efficiency.
8. Transmitter and Receiver Design
Transmitter: High-frequency AC generated by a
transistor-based oscillator is fed into the transmitting coil.
Receiver: A coil receives the AC signal which is rectified and regulated to
power the load.
9. Resonant Inductive Coupling
Using resonant frequency matching between transmitter and receiver improves efficiency and range. Capacitors are adjusted so that both coils resonate at the same frequency, typically around 100 kHz to 1 MHz.
10. Safety Considerations
Ensure that the system does not radiate high levels of electromagnetic fields that could interfere with other devices or pose health risks. Proper shielding and low power operation are essential for safe use.
11. Efficiency and Range
Efficiency decreases with distance. Typically ranges from 1 cm to 10 cm for inductive systems with efficiency ranging from 60% to 85% under optimal conditions.
12. Implementation Methodology
1. Design and simulate the oscillator and resonant circuits.
2. Build coils and assemble transmitter and receiver circuits.
3. Tune resonance using capacitors.
4. Test with different distances and loads.
5. Measure power transfer efficiency and output voltage.
13. Testing and Validation
Use multimeter and oscilloscope to measure output voltage, waveform, and frequency. Validate performance over different distances and with varying load conditions.
14. Advantages and Limitations
Advantages:
• No physical connectors
• Safe in wet or harsh environments
• Convenient for charging
Limitations:
• Limited range
• Lower efficiency
• Interference and shielding required
15. Applications
• Wireless phone chargers
• Electric vehicle charging
• Biomedical implants
• Industrial automation
• Consumer electronics
16. Future Enhancements
• Improved resonant coupling designs
• AI-based adaptive tuning
• Integration with IoT systems
• Multi-device charging platforms
17. Conclusion
Wireless Power Transmission is a promising technology that simplifies power delivery. The developed system demonstrates effective short-range power transfer and highlights areas for further improvement.