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High Voltage Circuits

Powerful ZVS Flyback Driver Circuit

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It is probably the most powerful and efficient flyback transformer driver that was fairly recently invented by Vladmiro Mazilli. It uses resonant zero voltage switching (also know as ZVS) to drive the flyback transformer. This means the MOSFET´s are designed to switch (on or off) when the voltage across them becomes zero. Because the MOSFET´s switches when there is no voltage across them, it will generate very little heat, the only source of heat is caused by the MOSFET´s internal resistance. Unlike the simple 555 timer flyback drivers, The ZVS flyback drivers will allow you to run your flyback transformers for much longer periods of time before the MOSFET´s overheat. If you get really good MOSFET´s, it might be even possible to run your ZVS flyback driver infinitely! (Or until the circuit is interrupted)
Not only the ZVS flyback driver is powerful, but it is very dangerous. You can easily pump several hundreds of watts into the flyback transformer and the output current would be around 50mA to 200mA (or even more), which is way above the lethal rate which is 10mA. Do NOT attempt to do this as your first flyback transformer driver project, I recommend you to start with using simple 555 timer flyback drivers before thinking about building an ZVS driver. And finally, you are solely responsible for any harm to others or damage or any other problems that a ZVS driver may cause. The ZVS driver should be used for educational and research purpose only.


Schematic Circuit
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Component List

• Flyback transformer
Newer flybacks are recommended as they are very robust. You can use an older flyback for higher current output, however, they are more likely to burn out due to excessive voltage.

• 2x 470Ω 2W resistors
The color code is yellow/purple/brown

• 2x 10KΩ 1/4W resistors
The color code is orange/brown/black

• 2x 12v 1/4W zener diodes

• 2x 400+ volts fast diodes
I used UF4007 diodes.

• 1x  inductor
The value is not critical but it should be 47uH to 200uH rated at 10A or more. You can find an inductor from a computer PSU or you can simply make your own, just wrap 20 turns of 16 gauge of enameled wire around a ferrite toroid.

• 1x 0.68uF 250v (or higher) capacitor
This capacitor must be bipolar and must be good quality, such as MKP ot MMC types. NEVER use an electrolytic capacitor, they will blow up. You can test various types of capacitors to see which one suits your ZVS driver well.

• 2x IRFP250 MOSFET´s
They are a bit pricey, however, you can use other MOSFET´s that has Vds 4x more than the power supply and has the Rds(on) lower than 150mΩ. Unfortunately those MOSFET´s are a bit over my budget so I used the IRFP254 MOSFET´s instead, not the best, but it is cheaper and it and it should give me good arc results. I also tried using the popular IRF540 MOSFET, however, it gave me very poor results.

• 2x small heatsink
They won´t be necessary if you are going to run your ZVS driver lower than 12v.

• Large variable voltage power supply
Now this can cost quite a big chunk of change, you can a computer power supply unit for 12v power source. If you want a higher voltage power supply, then you might want to consider modifying a microwave oven transformer, but this is another project. As I don´t have a large power supply so I used six  6v sealed lead acid batteries all in series to gain 36v to power my ZVS driver.

Then finaly the other bits and pieces you may need such as solder, thick wires, etc. 

The 5 turns of wire as the primary is not critical, you can add or remove windings for different performance.The voltage input to the driver may affect the number of turns required as well. 

The "47-200 µH" inductor can be customized to the desired output of the flyback transformer. In general, if you want a higher voltage, the inductor should have an higher value, if you want more current, the inductor should have an lower value. Also, an inductor is a ´must´ for the ZVS driver, without it, your ZVS driver may work poorly or not work at all.

Changing the value of the capacitor can also affect the performance depending on the flyback transformer, again, make sure you use good quality capacitor.

hvv a8f

Not only the ZVS flyback driver is powerful, but it is very dangerous. You can easily pump several hundreds of watts into the flyback transformer and the output current would be around 50mA to 200mA (or even more), which is way above the lethal rate which is 10mA.

Do NOT attempt to do this as your first flyback transformer driver project, I recommend you to start with using simple 555 timer flyback drivers before thinking about building an ZVS driver.

And finally, you are solely responsible for any harm to others or damage or any other problems that a ZVS driver may cause. The ZVS driver should be used for educational and research purpose only.

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Note:

Keywords : Powerful, Zvs, Flyback, Driver, Circuit, High, Voltage, Transformer
Writer : delon  |
8 Jul 2019 Mon   
|  42 Views
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