Wireless Power Transfer Mini Project

Wireless power transfer (WPT) technology allows electrical energy to be transmitted from a power source to an electrical load without physical connections. This mini project demonstrates a basic WPT system using a simple transistor circuit.

Project Overview

Objective: Build a basic wireless power transfer system using a transistor to drive the transmitter coil and a receiver coil to pick up the transferred power.

Components Required:

1. Transmitter Coil: Copper wire wound into a coil.
2. Receiver Coil: Copper wire wound into a coil.
3. Transmitter Circuit:
   • Oscillator Circuit: Generated by a simple transistor circuit.
   • Power Supply: DC source (e.g., 12V battery).
   • Transistor (e.g., NPN Transistor like 2N2222): To drive the transmitter coil.
4. Receiver Circuit:
   • Diode Rectifier: Converts AC to DC (e.g., 1N4007 diode).
   • Capacitor: Smooths the rectified signal (e.g., 1000µF capacitor).
   • Voltage Regulator: Provides a stable output voltage (e.g., LM317).
5. Load: Demonstrates power transfer (e.g., an LED or small motor).

Circuit Diagrams

1. Transmitter Circuit:
   • Oscillator Circuit: Create a basic oscillator using a transistor to generate a high-frequency signal. The transistor alternates current through the transmitter coil, creating an oscillating magnetic field.
   

2. Receiver Circuit:
   • Receiver Coil: Positioned to pick up the magnetic field generated by the transmitter coil.
   • Rectifier: The AC voltage induced in the receiver coil is rectified by the diode.
   • Capacitor and Voltage Regulator: Smooth out the rectified voltage and regulate it to power the load.
   


Construction Steps

1. Wind the Coils:
   • Transmitter Coil: Wind several turns of copper wire into a coil (e.g., 20-30 turns) and secure it.
   • Receiver Coil: Similarly, wind the receiver coil with a similar number of turns as the transmitter coil.
2. Assemble the Transmitter Circuit:
   • Create a basic oscillator circuit using an NPN transistor. Connect the transistor in a feedback loop with a resistor and capacitor to generate a high-frequency signal.
   • Connect the transistor’s collector to one end of the transmitter coil, and the emitter to ground.
3. Assemble the Receiver Circuit:
   • Connect the receiver coil to a diode rectifier to convert the induced AC voltage to DC.
   • Use a capacitor across the output of the rectifier to smooth the DC signal.
   • Attach a voltage regulator to ensure a stable output voltage for powering the load.
4. Testing and Adjustment:
   • Power the transmitter circuit and check if the receiver circuit is receiving power.
   • Adjust the position and alignment of the coils to maximize power transfer efficiency.
   • Verify that the load (e.g., an LED) operates as expected.

Applications

• Wireless Charging: Demonstrates basic principles of wireless charging for small electronic devices.
• Wireless Power Transfer: Serves as a foundational project for understanding more advanced wireless power technologies.

Conclusion

This wireless power transfer mini project illustrates fundamental principles of electromagnetic induction using a simple transistor-based oscillator. Adjusting coil alignment and circuit parameters can optimize power transfer, providing a basis for exploring more sophisticated wireless power systems.

RF Transmitter Receiver