Beyond Unity - Halfbridge circuit observation

baerndorfer posted this 14 November 2023

some time ago i build a halfbridge for doing experiments. the circuit looks like this,,,

i managed to design a scetch for arduino where i can adjust frequency and duty-cycle. the thing looks like this...

i use infineon IRS2304 as gate-driver IC.

when i look into datasheet i can find information about amount of time which is taken by IC to switch ON or OFF.

so it took between 70 and 120ns for IC to turn ON

and it took between 35 and 60ns to turn OFF

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today i did some experiments where i use this halfbridge and on oscilloscope screen you can find output from halfbridge on CH4 under load.

now as we can see, the RiseTime and FallTime of the output from halfbridge is incredibly fast compared to the data given by datasheet for gate-driver.

on CH2 we can see the Gate-Signal from highside-FET and CH3 represents Gate-signal from lowside-FET.

CH1 is Resonance-Signal from secondary coil-system which should be not relevant for the input situation.

at the moment i cannot understand, why the output signal has such sharp edges.

hopy some electronic-experts can help me understand better.

regards

B

halfbridge risetime falltime

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Fighter posted this 25 November 2023

My guess is that capacitor gets hot because it can't handle the high frequency. High-ESR.

I don't know if there are available 16KV capacitors but with low-ESR, that should solve the heating problem in my opinion.

Considering what we see in the thermal image, you should check it. If it reached that temperature I think it's already damaged. I doubt it's still functioning as in its specifications.

About the driver, I'm sorry, the image makes me think at the components I destroyed during my different experiments and especially during ZPM's development. Unavoidable losses, that's a part of the costs of our research...

Regards,

Fighter

"If you want to find the secrets of the universe, think in terms of energy, frequency and vibration."
		Nikola Tesla

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baerndorfer posted this 30 November 2023 - Last Edited 30 November 2023

to understand more i wound a new secondary coil. the difference to first one is, that i gave the windings more room. don smith said, that we can increase Q-factor by adding more distance between each windings.

i use asymetrical load (100W and 60W light bulp) and connect the center tap to GND.

CH1: primary coil Resonance / CH2: secondaryCoil(bottom) / CH3: secondaryCoil(top)

compared to old secondary coil, this new one is more powerfull in terms of output.

regards

B

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Jagau posted this 30 November 2023

I think the power analyzer will give you great insight.
Nice work Bearndorfer

Jagau

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baerndorfer posted this 04 February 2025

while playing with HF/HV resonance something astonishing happened.

below is a picture of a spark only connected to 'thin air'

resonance frequency: 544kHz

Vpp: 1200V

maybe the high frequency is key to open systems?

regards

B

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baerndorfer posted this 05 February 2025 - Last Edited 06 February 2025

10mm tungsten rod - yes baby !
what a nice flame... can you tell me what is burning here?
the heat is tremendous by the way.

many things to learn...

have a nice day

B

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Jagau posted this 05 February 2025

There may be an answer here in this link on a more advanced spark gap technique

https://teslauniverse.com/nikola-tesla/articles/advanced-spark-gap-technology

Really very interesting.

Jagau

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Inception posted this 06 February 2025

Be aware that high potential electrons aimed at a tungsten object can dislodge lower orbit electrons, causing higher orbit electrons to replace them ... emitting x-rays and visual, infrared, and ultraviolet light.

Protecting yourself from ionizing radiation exposure is highly recommended.

Is it possible that the intense heat is caused by a combination of these emissions?

Is this a thoriated tungsten rod?

"Thoriated tungsten electrodes contain radioactivity, they can ionize living tissue through the pathways of both external and internal radiation exposure."

Cutting, filing, or polishing this metal can produce various serious health issues.

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Jagau posted this 07 February 2025

I understand your warning inception, but Nicolas Tesla worked a good part of his life with spark gaps and at high voltages and died later than the average person.

It is always good to make warnings but for our small systems I worry less. Automobiles run on tungsten spark plugs center element (8 to 15kv) and there are millions of them in circulation, incandescent lamps run on tungsten too and Industrial welders produce huge spark with very high melting baths., to name just those.

It takes very specific conditions and well-tuned components and very high voltage to produce X-rays.

Beardorfer's work is important and goes in the right direction.

Jagau

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