ZVS Driver

A Zero Voltage Switching (ZVS) circuit is a popular device among electronics hobbyists for creating high voltages, generating arcs, transmitting power wirelessly, and performing induction heating, all in one circuit. This driver circuit is cost-effective, easy to make, and power-efficient.

Components List

he following components are required to make this project.

Designation	Parts	Quantity
Q1, Q2	IRFP250 N-Channel Power MOSFET	X2
D1, D2	1N4744 Zener Diodes	X2
D3, D4	UF4007 1000V 1A Ultra-Fast Recovery Diode	X2
R1, R2	10kΩ 1/4W Resistor	X2
R3, R4	470Ω 2W Resistor	X2
L1, L2	100uH, 5A Toroidal Inductor	X2
L3	1uH Air Core Inductor	X1
C1	1uF 600V Polyester Film Capacitor	X3

Circuit Diagram

The schematic of a ZVS driver circuit is shown below.

Circuit Explanation

The main switching elements in the driver circuit are two N-channel MOSFETs (Q1, Q2), which alternately turn ON and OFF. This circuit is powered by a 12-48V DC voltage supply. The 15V Zener diodes (D1, D2) are used to protect the gates of the MOSFETs from overvoltage. Resistors (R1, R2) are used to limit the gate current to protect the MOSFETs, while pull-down resistors (R3, R4) ensure that the gates of the MOSFETs are properly discharged when they are supposed to be OFF.

When MOSFET Q1 turns ON, current flows through inductor L1 to ground, storing energy in its magnetic field. This drops the gate voltage to zero, turning Q1 OFF. The stored magnetic energy in L1 is then converted back into electrical energy, which flows through inductor L3, diode D3, and resistor R1, discharging the energy.

Similarly, when MOSFET Q2 turns ON, current flows through inductor L2 to ground, storing energy in its magnetic field. This drops the gate voltage to zero, turning Q2 OFF. The stored magnetic energy in L2 is then converted back into electrical energy, which flows in the opposite direction through inductor L3, diode D4, and resistor R2, discharging the energy.

The capacitor C1 and inductor L3 together form a resonant circuit, determining the oscillation frequency of the circuit. These oscillations generate a rapidly alternating magnetic field around inductor L3. When a conductive metal object is placed near this magnetic field, it induces circular currents within the metal, known as eddy currents. These eddy currents flow through the metal's resistance, causing it to heat up due to the Joule effect, or resistive heating.

If the circuit is connected to a flyback transformer, the high-frequency oscillations can be stepped up to a much higher voltage in its secondary coil. This high voltage can then be used for applications such as driving a Tesla coil or as a high-voltage arc generator. Additionally, the continuously generating high-frequency AC signals in the primary coil (L3) of the ZVS driver induce current in a nearby receiver coil through inductive coupling.