ZVS Induction Heater + Tank Calculator

Let us build a full ZVS driver + tank circuit simulator super useful for trying different values of voltage, frequency, inductor, capacitor, and seeing how your ZVS-based induction heater behaves.

What This Simulator Does:

Calculates:

• Resonant frequency (f)
• Required inductance (L)
• Tank current (approximate)
• Reactive power (Q-factor)
• Heating efficiency range estimate
• Shows warnings if parameters are unsafe

How It Works Behind the Scenes:

• Z = Xl - Xc → reactance difference creates the LC resonance tank
• I = V / Z → approx current in the LC loop (not including switching losses)
• Q = Xl / Z → higher Q means sharper resonance and better energy recycling
• Reactive Power shows how much VA is circulating (not real power)

Design Tips for Best Results:

Parameter	Recommended Value
Frequency (f)	50kHz to 200kHz
Capacitance (C)	0.1 to 2 µF (MPP/MKP type)
Inductance (L)	1 to 20 µH (air-core or copper tubing)
Voltage (V)	12V to 36V (ZVS driver safe range)
Tank Current (I)	Preferably try to Keep under 30 A unless heavy copper used

How You Can Keep Tank Current Below 30 Amps:

Move Slightly Away from Resonance (Detuning)

Tank current goes to peak only at exact resonance. If you shift the frequency a bit above or below resonance then current drops without killing heating.

Example:
Resonance at 100 kHz
Try operating at 105–110 kHz or 95–90 kHz

This reduces I = V / (Xl - Xc) because Xl ≠ Xc anymore.

Increase Net Reactance (Z = Xl - Xc)

Your current is high because:

Z = |Xl - Xc| is very small → I = V / Z becomes very very big...

To increase Z and reduce current, you can:

a. Reduce Capacitance

Use lower value capacitor. For example:

• Instead of 0.33 µF, Try 0.1 µF.
  This increases Xc which increases |Xl - Xc| → lowers current

b. Increase Inductance

Use slightly more turns or wider coil

• Instead of 7.6 µH, Try 15 µH.
  This increases Xl which helps in detuning and results in less current.

Try keeping Z around 0.8 Ω minimum

So for 24V:

I = 24 / 0.8 = 30 A

Lower the Supply Voltage

Tank current is directly proportional to voltage:

I = V / Z

So instead of 24V we can use 12V:

• 12V supply
  Same Z = 0.05 Ω
  Now I = 12 / 0.05 = 240 A (still high, but 50% lower than 24V case)

But better if you combine lower voltage + detuning → then real current can go under 30A.

Add a Small Series Resistance (Lossy Method)

This is a crude method but works:

• Add 1 to 2 Ω high-watt resistor in series with tank.
• Will limit current but waste energy as heat.
• Use only for small systems, not recommended for powerful heaters.

Use PWM Controlled Supply Instead of Constant Voltage

If you use a PWM buck converter to softly power the ZVS circuit then you can:

• Limit the average input voltage
• Use a current sensor to cut power at 30A
• Gradually ramp up to avoid peak surges

This gives full control like a professional induction heater.