Halfbridge circuit observation

  • 592 Views
  • Last Post 30 November 2023
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

---

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

Attached Files

Order By: Standard | Newest | Votes
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

---

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

Attached Files

Jagau posted this 14 November 2023

Hello Bearn

For the 2n60s5 infeon technologies says that you are within the standards.

However the tests carried out in the laboratory are only a guide the conditions of Vds and Vgs can be completely different and given different results and there is also another condition the type of load used.

As you see in this datasheet you are correct.

 

Their tests are generally on linear loads in ideal laboratory conditions.

Do not forget, Rt / Ft is drains source waveform and delay r / delay f is for gate waveform

I don't know if that's what you want to know but it might help.

Jagau

baerndorfer posted this 21 November 2023

with this halfbridge i energize a coil which is placed between 2 capacitors. the first capacitor acts like a reservoire and the second capacitor is the resonance-capacitor.
as secondary coil i use a opposing-coil. the benefit of such coil is, that the magnetic vectors cancel each other out. so technically the energy reduce to zero and you get no magnetic force, that acts against the primary coil.

this is how it looks on the bench...

i use 100W lightbulb and connect it directly to secondary coil. when you get the correct distance the output on load is maximum and you cannot measure a voltage. so the voltage on bulb is zero, and the current is maximum. this is what john bedini describes in his work when he studied Tesla. this is called current-node.

have a nice day,

B

 

AlteredUnity posted this 22 November 2023

Very interesting, nice setup Baerndorfer, thanks for sharing. I see you are using somewhat high voltage, does the effect take place with lower voltage?

baerndorfer posted this 22 November 2023

you can have the same effect with lower voltage, but then you should have a high frequency. in my case i use 100W light bulp. if i like to have full brightness i need 3kV and about 900kHz. i can have the same brightness from bulp if i run 10kV at 300kHz.

magnetic flux is defined as the number of field lines passing through a given area and is a way of looking at the total magnetic field in that area. we can say the induced voltage in a circuit is propotional to the rate of change of the magnetic flux over time. 

voltage and frequency plays a keyrole here.

regards

B

Fighter posted this 22 November 2023

Hi Baerndorfer,

you can have the same effect with lower voltage, but then you should have a high frequency.

...

voltage and frequency plays a keyrole here.

Hopefully this is true with Don Smith's tech too so I will not need to work with high-voltage in my Don Smith Effect experiments.

But just in case I will be forced to use high-voltage, what do you use to obtain it ? Don Smith was using neon transformers like Bertonee NPS-12D8S and NPS-12D10S :

What do you use for high-voltage and also how dangerous is to work high-voltage ?

Thanks for sharing your experiment !

Regards,

Fighter

"If you want to find the secrets of the universe, think in terms of energy, frequency and vibration."
Nikola Tesla
YoElMiCrO posted this 22 November 2023

Hello everyone...

@Baerndorfer.

Driver properties only report the times you measure
on its output, this is with no charge attached to it, just that.
What matters when you have a switch coupled is the current
that the driver is capable of delivering, let me explain...

The IRS2304 has a maximum peak current at the output
60mA (Source) and 130mA (Sink), now depends on the mosfet you dock,
specifically to the total load gate charge, this load depends on the voltage of the 
drain among other things.
The way to control the times is with the serial resistance to the mosfet gate,

Rg~Vcc/(Tgc/T)

That's roughly why the times don't add up, it really is
more complicated than that, since it depends on many variables.
Almost always the time of descent is longer than the time of ascent, in this case
it is usually equalized with two resistors, one for Ton and one with a diode in
inversely for Toff, so that the dead time between the two is fulfilled and there is no
between the two rails.

I hope I was able to help you.

YoElMiCrO.

baerndorfer posted this 22 November 2023

Hi all,

@Fighter.

To obtain HV on my coil i use simple tank-circuit (L-C in series). I showed it in above image. Halfbridge is feeding energy into this system till resonance is reached. You can reach very high voltages with this method and it is not complicated. I can touch this 'radio frequency' at high voltage but did not recommend it to others. You remember touching an electric fence as a kid? It is that feeling which comes through your veins when we lay our hands onto this stuff. 😎

@YoElMiCrO.

Thank you for explaining. I try to understand what you say but i'm sure it will take couple of days till i get it fully! Always a pleasure reading from you. 

thx

Fighter posted this 23 November 2023

Understood, so with my device I should try with a capacitor in series with the coil so I wouldn't need the switching circuitry anymore. I thought you have high-voltage on input from a device like Don Smith's transformer.

So high-voltage but high-frequency, if touched accidentally the energy is circulating just through the skin, not going deep into the body and become life-threatening.

I'm trying to not spam your thread so I got just one more question: how does the scope handle this high-voltage, isn't there the risk of damaging it ? I must check what's the upper voltage limit of my scope. I suppose setting the probes to 10X would be enough to avoid any damage to my scope.

Thank you for your explanations, I'm stopping here with my "spam" on your thread... 🙂

Regards,

Fighter

"If you want to find the secrets of the universe, think in terms of energy, frequency and vibration."
Nikola Tesla
baerndorfer posted this 23 November 2023

if i understand don smith correctly then he always tries to disturb the ambient background. he used high voltage and high frequency in a resonating system with coils and capacitors. on some of his circuits he extracts energy with a second coil which i assume to be made in opposing-style. he always mentioned, that the condition in which he operates his devices has to be 'resonance'. so the whole thing should be in resonance. from the first wire till the end of structure. he said, that a wire which is placed in a strong field will act like antenna. if the length of wire meets a harmonic from main frequency, then this wire can become a dipole which feeds additional energy into the system. 

everything seems important.

he said, that a coil which is wound in opposing style will transform the energy into its 2 main parts. one part (voltage) and the other part (amperage). he also talks about spinning the electron left or right makes a difference. in his book he wrote about this.

instead of high-voltage module which he used for driving his primary coil i use my halfbridge which energizes a L-C tank in resonance. the effect is the same with both methods. the primary coil is in resonance and the voltage is in the kilovolt region. these modules operate at 30kHz which seems to be enough for don smith. i prefer to have a much higher frequency to begin with because i can disturb the background even more. and that can be a good thing.

for measurements in the kilovolt region i bough some 1:1000 probes. but it is not really needed. you can use 1:10 probe and connect it over the isolation from cable. you will not get a accurate voltage reading, but in that region we should only focus on quality of resonance signal. 

still many things to learn....

thank you for questioning! i will always answer if i can.

regards

B

 

 

baerndorfer posted this 24 November 2023

two observations...

the temperature on capacitor is too hot (58.8o C). maybe because of high frequency, but i'm within the limits of 16kV which this capacitor can handle. the primary coil (44o C) seems ok. i cannot see any temperature coming from secondary coil where the load is connected. interesting...

finally some of the IRS2304 died unexpectedly. nice!

regards

B

Close