driving plasma spark ignition

Hi guys, I'm new here and a novice with arduino. Have some experience with electronics but the following is a HV project that I've been working on.

The project is a plasma spark ignition setup for a gasoline generator to be run on fuel and water vapor. The ignition system is basically a capacitive discharge ignition. The cap is charged with a solid state bedini circuit that charges the cap to 150-300 volt. A BT151 800V thyristor is used to dump the cap to the Plus side of the ignition coil. Up untill now the triggering of the BT151 was done mechanically with contact points but we would like to use a Hall sensor in the future.

Currently I have the system on the testbench and would like to trigger the thyristor with the PWM output of the arduino. I have tried to take a output and connect it to gate but that didn't work for long, I may have fried output 11. I would love to get some help to setup the arduino board and protect it from HV spikes . Could I just use diode like 1n4007 on the output in series to the gate of the thyristor??

Thanks for your help.


A schematic and perhaps a photo would help.

The spark is a lot more than the voltage in the capacitance. If during testing that spark injects the circuit, the Arduino is destroyed.

So I would suggest a optocoupler. Perhaps a fast one, since most common optocouplers are slow. The Arduino would use a resistor and the optocoupler. You need to make a circuit to trigger the thyristor. Perhaps you need an extra transistor.

Most things in a car are extensively developed for optimal use. It's not easy to make something better with your own circuit.

Hi Erdin,

After your advice to use a optocoupler I did some more fiddling with the circuit but still unable to get that to work. However, even without the optocoupler I still got it working for test purposes and play :slight_smile:
I made a short clip for you to see the setup of the ignition system. A circuitscheme will come but you will get the idea. No idea how the circuit is really triggering right now, the gate is connected with diode to neg rail of the oscillator. Frequency changes as I increase voltage on the power supply.
Here’s the video: http://youtu.be/YVmUk9ox96I

That reminds me when I used a thyristor with a xenon flash to make a strobe… Worked great, until things started to melt. So don’t underestimate the energy you are working with.