This post is for 500 watt induction heater.
Here the coil makes a strong magnetic field that changes very quickly.
When anyone puts metal in the coil the metal heats up.
This happens because of swirling currents in the metal called eddy currents.
There is another effect from the metals properties that causes heating but its a bit more complicated.
Even though the coil is small it needs a high current around 100 amps to work well.
To make this circuit work efficient we should add another part called a capacitor that needs to be a specific size to match the coil.
This whole system with the coil and capacitor needs to run at a special frequency for best results.
What is a Induction Heater Circuit:
An induction heater circuit is an electronic circuit that uses the principle of electromagnetic induction to generate high temperatures in a conductive material typically a metal.
These circuits are commonly used in applications such as metal hardening, cooking, induction heating cooktops and various industrial processes.
The basic idea behind induction heating is to use a high frequency alternating current AC to create an electromagnetic field and when a conductive material is placed within this field it generates eddy currents that cause concentrated heating.
Circuit Diagram:
Parts List:
| Component | Description | Quantity |
|---|---|---|
| Resistors | All resistors are 1/4 W MFR unless specified | |
| 100k | 2 | |
| 10k | 1 | |
| 4.7Ω 4W | 1 | |
| 15Ω | 2 | |
| Capacitors | ||
| PPC | 330nF 250V | 5 |
| PPC | 330pF 1kW | 1 |
| PPC | 4.7nF 1kW | 1 |
| PPC | 470nF 250V | 2 |
| Electrolytic | 100uF 25V | 2 |
| Semiconductors | ||
| Diode | 1N4007 | 4 |
| Diode | BA159 | 1 |
| Zener Diode | 16V | 2 |
| MOSFET | IRF840 | 2 |
| IC | IR2153 | 1 |
| Neon Bulb | 1 | |
| Coil | copper wire or tube | 1 |
| Filament Bulb | 200 – 500W | 1 |
How to Build:
- Build a coil with 12 to 30 turns on a 3 to 10 cm diameter by winding the copper wire or tube.
- To reach the required resonance capacity connect a minimum of six capacitors.
- To control the MOSFETs put the IR2153 circuit to work.
- Attach small heatsinks to the MOSFETs.
- Connect a neon lamp to indicate resonance.
- Supply the control circuit with 12 to 15V DC using a wall outlet adapter or other suitable means.
- Wind approximately 20 turns of 1.5 mm diameter copper wire on an 8×10 mm ferrite core.
- Adjust the air gap for power control.
Tune the Frequency:
- Adjust the operating frequency between 20 and 200 kHz with the potentiometer.
- Use the neon bulb to keep an eye on the resonance indicator.
- Turn the system ON and watch how it works.
- Throughout operation keep an eye on the coils and resonance capacitors heat production.
Cautionary Note:
- Take all necessary safety precautions and proceed at ones own risk while working on this 500 watt induction heater project.
- In this circuit everyone should follow the possible risks and take the necessary precautions.
- Always put safety first and if anyone lack knowledge with high voltage systems than think about getting help from an electrical specialist.
Formulas:
A 500 Watt induction heater must be constructed safely and effectively leading to the need for careful consideration of several factors and complex the calculations.
Here are some essential formulas to use in order to help one in designing this circuit:
Power Formula (P):
P = VI
where,
- P is power in watts
- V is voltage in volts and
- I is current in amps.
This formula connects the circuits voltage and current to the 500W induction heaters output power.
Coil Impedance Z:
Z = √(R2 + X2)
where,
- Z is impedance in ohms
- R is resistance in ohms and
- X is reactance in ohms
The total impedance of the induction heater coil is calculated using this formula which is the product of its resistance R and inductive reactance X.
The coil configuration and operation frequency influence these values.
Resonant Frequency (f):
f = 1 / (2π√(LC))
where,
- f is frequency in hertz
- L is coil inductance in henrys and
- C is capacitance in farads.
The resonance frequency of the circuit which is required for effective power distribution to the heated object is calculated using this formula.
The resonant frequency is affected by the coil inductance L and any additional capacitance C.
Conclusion:
Because high frequency and high power circuits can be dangerous safety measures should be taken into account while constructing or operating a 500 watt induction heater circuit.
The specific requirements of the application such as the material properties and heating temperature will also have an impact on the induction heater circuit design .
References:
Design and Construction of Power System for Induction Heating