Solar based Wireless Power Transfer (WPT) Project

Description

Wireless Power Transfer System using Inductive Coupling enables contactless energy transmission through magnetic fields for efficient wireless charging of electronic devices. This circuit-based project uses oscillator, MOSFET driver, and transmitter–receiver coils to demonstrate real-time wireless power transmission with compact and efficient design.

—If coils are properly aligned → ⚡ Wireless Power Transfer Active
—If receiver enters magnetic field range → ✅ Power Transmission Successful

Introduction

#WirelessPowerTransfer #WirelessCharging #InductiveCoupling #ElectronicsProject #FinalYearProject

Award-Winning Capstone Project Idea: Wireless Power Transfer System using Inductive Coupling – Perfect for Final Year Engineering Students (CSE, ECE, EEE, Mechanical, Science)

Introduction

The transmission of electrical energy has traditionally relied on wired connections, which introduce limitations such as power losses, safety risks, mechanical wear, and restricted mobility. With the rapid advancement of portable electronics, electric vehicles, and smart systems, there is a growing demand for efficient, safe, and contactless methods of energy transfer. Wireless Power Transfer (WPT) has emerged as a transformative technology that enables electrical energy transmission without the need for physical conductors.

Wireless power transfer operates on the principle of electromagnetic induction, which is mathematically described by Faraday’s Law:

V = -N (dΦ/dt)

where V represents the induced voltage, N is the number of turns in the coil, and Φ denotes the magnetic flux. When an alternating current flows through the transmitter coil, it generates a time-varying magnetic field. This magnetic field induces an electromotive force in the receiver coil placed within its range, enabling wireless transfer of energy. The efficiency of this process depends on factors such as coil alignment, distance between coils, operating frequency, and coupling coefficient.

The concept of wireless energy transmission dates back to the late 19th century, when Nikola Tesla conducted pioneering experiments demonstrating the possibility of transmitting power through air using resonant inductive coupling. Although the technology was not widely adopted at that time due to practical limitations, recent advancements in power electronics and circuit design have enabled efficient and compact wireless power systems suitable for modern applications.

From a global perspective, energy efficiency is a critical concern. It is estimated that approximately 8–15% of total electrical energy is lost during transmission and distribution processes. Wireless power transfer systems, when optimised, can reduce connector-related losses, eliminate wiring complexities, and improve reliability in specific applications. Additionally, the removal of physical connectors minimises maintenance requirements and enhances safety, particularly in environments where wiring is difficult or hazardous.

The importance of wireless power transfer lies in its ability to provide seamless and convenient energy delivery. It eliminates the need for cables, reduces clutter, and enables operation in sealed, rotating, or inaccessible systems. This makes it highly suitable for next-generation technologies such as wearable electronics, biomedical devices, autonomous systems, and IoT-based smart environments.

The proposed wireless power transfer system utilises an oscillator-based switching circuit with a MOSFET driver to generate high-frequency signals, which are applied to a transmitter coil. The resulting magnetic field induces electrical energy in the receiver coil, which is then rectified and filtered to obtain a usable DC output. The system demonstrates a compact, cost-effective, and efficient implementation of inductive wireless power transmission.

Wireless power transfer has a wide range of applications, including wireless charging of smartphones and laptops, electric vehicle charging systems, powering remote IoT sensors, biomedical implants such as pacemakers, industrial automation systems, and consumer electronics. Its ability to deliver power without physical contact makes it a key technology for future smart cities and advanced engineering systems.

Objectives

1. To design and develop a wireless power transfer system using inductive coupling for contactless energy transmission between transmitter and receiver coils.
2. To analyse the effect of coil alignment, distance, and coupling on the efficiency and stability of wireless power transmission.
3. To implement an oscillator and switching circuit to generate high-frequency signals required for efficient magnetic field generation.
4. To demonstrate practical wireless energy transfer by powering a low-voltage electronic load through induced voltage at the receiver side.

Block Diagram

Original Circuit Diagram

Components Required

1. CD4047 IC (Astable Multivibrator / Pulse Generator)
2. MOSFET (IRF540 or equivalent)
3. Transmitter Coil (Copper Winding Coil) 50 Turns
4. Receiver Coil (Copper Winding Coil) 150 Turns
5. Diodes (1N4007)
6. Resistors 330 Ω, 1 kΩ, 10 kΩ , 100 kΩ390 kΩ220 Ω
7. Capacitors0.01 µF, 1000 µF / 25V (multiple), 1000 µF / 35V (multiple),
8. LED Indicator
9. Zener Diode (5.1V or 5.6V)
10. Voltage Regulator (5V, if used)
11. Battery Rechargeable / DC Power Supply (12V)
12. PCB / General Purpose Board
13. Connecting Wires
14. Load (LED / Small Device like mobile or module)
15. Solar Panel (for alternative power source)
16. Charging Module / Protection Circuit
17. Mobile Phone (for demonstration of wireless charging) (not Provided with project)

Working Theory of Wireless Power Transfer System with Calculations

The proposed wireless power transfer system works on the principle of electromagnetic induction, in which electrical energy is transmitted from a transmitter coil to a receiver coil without direct wire connection. In this circuit, the CD4047 IC is used as a pulse generator, the IRF540 MOSFET acts as a switching device, and the transmitter and receiver coils transfer power through a changing magnetic field.

A DC supply is given to the transmitter side. The CD4047 is configured in astable mode and generates a square wave signal, which is fed to the gate of the IRF540 MOSFET. The MOSFET switches rapidly and causes current to flow through the transmitter coil, producing a time-varying magnetic field. When the receiver coil is brought near the transmitter coil, this magnetic field links with the receiver coil and induces voltage in it. The induced AC voltage is then rectified using a diode and filtered using a capacitor to obtain usable DC output.

The basic law governing this system is Faraday’s Law of Electromagnetic Induction:

V = -N (dΦ/dt)

where
V = induced voltage
N = number of turns
Φ = magnetic flux

This shows that the induced voltage depends directly on the number of turns in the coil and the rate of change of magnetic flux.

Given Specifications

Transmitter coil turns, Nt = 50
Receiver coil turns, Nr = 150
Transmitter voltage, Vt = 6 V
Receiver voltage, Vr = 8 V
Coil wire diameter = 0.3 mm

1. Turns Ratio Calculation

The turns ratio between receiver and transmitter coil is:

Turns ratio = Nr / Nt

Turns ratio = 150 / 50 = 3

So, the turns ratio is:

Turns ratio = 3 : 1

This means the receiver coil has three times more turns than the transmitter coil.

2. Ideal Voltage Ratio

In an ideal inductive system, the voltage ratio is proportional to the turns ratio:

Vr / Vt = Nr / Nt

Substituting your values:

Vr / 6 = 150 / 50

Vr / 6 = 3

Vr = 18 V

So, the ideal theoretical receiver voltage should be:

Ideal receiver voltage = 18 V

3. Actual Received Voltage

From your practical result:

Actual receiver voltage = 8 V

This means the system is not achieving the ideal 18 V because of practical losses such as:

• air gap between coils

• leakage flux

• imperfect alignment

• coil resistance

• switching losses in MOSFET

• rectifier diode losses

• no magnetic core between coils

4. Voltage Transfer Efficiency

Since ideal voltage is 18 V and practical voltage is 8 V, the voltage transfer effectiveness can be estimated as:

Voltage efficiency = (Actual output voltage / Ideal output voltage) × 100

Voltage efficiency = (8 / 18) × 100

Voltage efficiency = 44.44 %

So, the practical voltage transfer relative to the ideal turns-ratio value is:

Voltage transfer efficiency = 44.44 %

5. Practical Gain over Input Voltage

Even though the ideal was 18 V, your actual measured output is still greater than input:

Voltage gain = Vr / Vt

Voltage gain = 8 / 6 = 1.33

So:

Voltage gain = 1.33 times

This means the receiver side voltage is about 33.3% higher than transmitter voltage, mainly because the receiver coil has more turns.

6. Frequency of CD4047

The oscillation frequency of CD4047 in astable mode is given by:

f = 1 / (4.4RC)

From your circuit image, the timing components appear approximately as:

R = 390 kΩ
C = 0.01 µF

Converting units:

R = 390 × 10^3 ohm
C = 0.01 × 10^-6 F = 10^-8 F

Now,

f = 1 / (4.4 × 390 × 10^3 × 10^-8)

f = 1 / (4.4 × 3.9 × 10^-3)

f = 1 / 0.01716

f = 58.27 Hz

So, the approximate oscillation frequency is:

f = 58.27 Hz

If your 100 kΩ preset is adjusted along with the resistor network, the actual frequency may vary around this value.

7. Ripple Voltage Formula

After the receiver coil induces voltage, the diode rectifies it and the capacitor smooths it. Ripple voltage is given by:

Vripple = Iload / (fC)

Since load current is not provided, numerical ripple cannot be calculated exactly. But this formula shows:

• ripple decreases when capacitance increases

• ripple decreases when frequency increases

Your use of 1000 µF capacitor helps reduce ripple and gives smoother DC output.

8. Coupling Statement

The coupling coefficient is:

k = M / √(L1L2)

where
M = mutual inductance
L1 = inductance of transmitter coil
L2 = inductance of receiver coil

Since inductance values are not given, exact coupling coefficient cannot be calculated. But from the measured output of 8 V instead of ideal 18 V, it is clear that the coupling is moderate and not ideal, which is normal in air-core wireless power transfer systems.

9. Effect of Number of Turns

Because:

Nr = 150 and Nt = 50

the receiver coil has more turns, so it can induce a higher voltage than the transmitter side, according to:

Vr ∝ Nr

This is why your receiver side is producing 8 V from a 6 V transmitter side, even under non-ideal conditions.

10. Effect of Wire Diameter

Your coil wire diameter is:

d = 0.3 mm

This affects current carrying capability and resistance. A 0.3 mm copper wire is suitable for small wireless power transfer setups because:

• it allows compact winding

• it reduces excessive coil bulk

• it is suitable for moderate current

• it helps maintain a reasonable number of turns

However, thinner wire has more resistance than thicker wire, which can increase copper losses and reduce efficiency.

Calculated Output Summary

Transmitter turns = 50
Receiver turns = 150
Turns ratio = 3 : 1
Input voltage = 6 V
Ideal output voltage = 18 V
Practical output voltage = 8 V
Voltage gain = 1.33 times
Voltage transfer efficiency = 44.44 %
Approximate CD4047 frequency = 58.27 Hz
Coil wire diameter = 0.3 mm

Final Working Theory Paragraph

The wireless power transfer system uses a CD4047 astable multivibrator to generate square wave pulses, which drive the IRF540 MOSFET. The MOSFET switches the transmitter coil and creates a changing magnetic field around it. The receiver coil, having 150 turns compared to 50 turns in the transmitter coil, captures this magnetic field and develops an induced voltage according to Faraday’s Law. For a transmitter voltage of 6 V, the ideal receiver voltage based on turns ratio is 18 V, whereas the practical measured output is 8 V due to coupling losses, leakage flux, and circuit losses. The practical voltage gain is 1.33, and the voltage transfer efficiency relative to the ideal case is 44.44%. The 0.3 mm coil wire provides a compact winding structure suitable for this low-power wireless charging system.

************************

wireless power transfer project, wireless charging system Arduino, inductive power transfer project, CD4047 wireless power system, IRF540 MOSFET project, transmitter receiver coil project, wireless electricity transfer, inductive coupling project, wireless charging using coils, engineering wireless power project, WPT system Arduino, low power wireless charging system, magnetic induction charging project, final year electrical project, electronics wireless power system, BTech project wireless charging, ECE power electronics project, IoT wireless charging system, smart wireless energy transfer, engineering project ideas, capstone project electronics, wireless power transmission system, solar wireless charging project, contactless power transfer system

🔹 Project Titles (Students Can Use)

1. Design and Implementation of Wireless Power Transfer System Using CD4047 Oscillator and MOSFET Switching
2. Low-Power Inductive Wireless Charging System Using Transmitter and Receiver Coils with Efficiency Analysis
3. Wireless Energy Transfer System Using Magnetic Induction and MOSFET-Based Switching Circuit
4. Efficient Contactless Power Transmission System Using CD4047 Multivibrator and Inductive Coupling
5. Smart Wireless Power Transfer System for Low Voltage Applications Using Coil-Based Energy Transmission
6. Wireless Charging Prototype Using Magnetic Field Induction with Performance and Efficiency Evaluation
7. Design of Inductive Power Transfer System Using IRF540 MOSFET and Coil Optimization Techniques
8. Compact Wireless Energy Transmission System Using Square Wave Oscillator and Coil Coupling
9. Low-Cost Wireless Power Transfer Model Using Inductive Coupling and Oscillator-Based Switching
10. Wireless Power Transmission System Using Coil Turns Ratio and Practical Efficiency Analysis

Contact us:
👨🏼‍🏭𝗩𝗶𝗽𝗶𝗻 𝗞𝘂𝗺𝗮𝗿 𝗦𝗵𝗮𝗿𝗺𝗮
Ph.D., M.Tech, B.Tech in ECE
🎓Lecturer 🚀#Researcher #Drone #Robotics

WhatsApp : https://wa.me/919810326343

✅🔥Follow us on

📺 YouTube 👥 Facebook 🐤 Twitter  📸 Instagram👨🏻‍🎓 LinkedIn

𝗔𝗯𝗼𝘂𝘁 𝗨𝘀 :
𝗫𝗶𝗟𝗶𝗥 𝗧𝗲𝗰𝗵𝗻𝗼𝗹𝗼𝗴𝗶𝗲𝘀™ is India’s 🔖Top rated & Leading R&D Company. It’s an ISO 9001:2008 Certified Company & Govt Approved under MCA & it was established in 2012.