Radiant Half Bridge Circuit is Flawed, PCB is not

hi my name is evo and i'm doing research into nikola tesla's impulse electricity i published my radiant half bridge circuit in november 2020 but it does not work as i intended there is a design flaw that i am not able to fix but luckily the pcb still is functional i realize the dual mosfet pcb can now be used to simultaneously switch to mosfets in series which i now use in my tesla oscillator circuit let me explain what went wrong and how it still can serve its new purpose this is the november 2020 radiant halfridge circuit the intention was to produce alternating unipolar impulses but it can't as it is ringing all over the place i will show you three small experiments to explain what is going wrong let's start with showing you the ringing of a coil at its resonant frequency with a simple circuit using a six volt battery first thing we'll do is switch a coil that is grounded connected up to a battery of six volts we'll hook up a probe so we can see what the coil is doing and what we'll do is make a very short connection over here when it's connected the l1 coil is magnetized and when disconnected the l1 coil will start ringing like so it will start with a negative voltage because we are switching the positive which is the high side if we would be switching the negative then we would start with a positive voltage so let me explain the setup first i've got a battery here six volts i put a ground connection on it it attaches the outside rim of the coil to the negative and then we have the inside rim of the coil here i've connected it to the high voltage probe and what i will do is connect it very shortly to the positive of the battery and then disconnect it meanwhile the oscilloscope will trigger and will record what is happening with the voltage on the coil i'll very shortly tap it like this a little spark what this did is magnetize the coil and when it was disconnected the coil starts ringing which is at the resonant frequency of this coil here you can see the oscilloscope i've recorded what happened and zoomed in i'll zoom out again you can see it is ringing and that ringing dies off due to the resistance of the coil which transfers the resonant electric energy into heat and radiation if we zoom in to the beginning it's a little bit erratic but you can see it starts off with a negative voltage and this is because i switched the positive voltage on and off in the next experiment i will show you what happens when i switch the six volt battery on and off with a mosfet but first we'll take a look at the body diode of a mosfet let's take a look at a mosfet this is the drain this is the gate and this is the source of the mosfet now i've got something here i did that on purpose there is a body diode over here this body diode is like a valve that only passes electric energy in one direction and this body diode is always part of a mosfet due to the way a mosfet is being made normally this is not really a problem but we will be switching a coil and then this coil will start ringing like so this part of the negative voltage when the mosfet is turned off will not be able to pass anything because the diode is blocking the negative voltage but here in the second half of the cycle of the resonant l1 we have a positive voltage and a positive current and this can pass through that body diode and then it goes up to the drain back into the battery and this doesn't need to be a problem but i can produce 3500 volt impulses so you can imagine that when 3500 volts is flying out of that mosfet then the power supply might be damaged so to protect it we place another diode over here right before the positive power supply this way when that second half and the positive voltage is passing through the body diode it will be blocked by this diode again to be clear there are igbts without body diodes but igbts do not turn off quick enough to produce proper impulses so i only use mosfets so positive power supply voltage flows through this diode through the mosfet into the coil energizes it then the gate voltage is lowered the mosfet turns off the coil starts ringing we first have a negative voltage which is blocked by the diode and the mosfet but then we have a positive voltage which passes through the body diode up to the drain and there it is blocked again by this diode let's take a look at how this looks in a experiment so here we have the setup with the single mosfet this pcb turns the mosfet on and off by using a coax i am hooked up to the signal generator which produces a 50 duty cycle square wave on this pcb also is a diode and the battery is grounded the coil is hooked up to the outside rim as before inside rim is connected to the source of the mosfet and then i have another lead going to my high voltage probe to see what is going on between the source and the coil i've got another battery pack here this is purely to provide 19 volts to the gate driver ic that switches to mosfet so this can be ignored also the the electronics on top that's not connected it's from another project and i've got a 12 volts power supply externally for the fan so let me turn it on and we'll take a look at the scope at what is happening here you can see the signal in purple when the mosfet is turned on it's high and when it's turned off it's low and as you can see when it is turned off the coil starts ringing this is at 53.9 kilo cycles per second so the resin frequency is the same as before around 1 mega cycles per second as you can see it starts again at the negative voltage because the velocity voltage is being switched so the coil now is ringing we do not have a single impulse if we would want to have a single impulse then i would have to connect a capacitor from the drain to the ground let me show you this so we've seen that it remains ringing and this is not what we want what we want is to have a single impulse so only a half wave and then we want the voltage to stay zero here on the l1 coil between the coil and the source where we are probing it now how do we do this we have a solution for this we can do this by adding a capacitor between the drain and the diode to ground what this does is store that positive energy from this half so when that half is being created it is passing through the body diode up to the drain it is blocked by this diode because it is in reversed but now it can charge up the capacitor and then all that energy is charged in that capacitor so it doesn't appear here anymore that's really nice the capacitor is large enough that that voltage will never rise to a very high voltage it keeps it very low because that's a large capacitor then it stays in that capacitor it stays charged until the mosfet is being turned on again and then it discharges over the l1 coil again once the capacitor is discharged enough the diode will open up again and the positive voltage is powering the l1 coil again for the next cycle so the energy is fully stored and reused by using this method let's take a look at this okay this is the new setup i've got a capacitor here which is a wema mkp 10 0.68 micro farad's 2000 volts dc 700 volts ac i connected it to the drain of the mosfet so it's between the diode and the mosfet in and to the ground the negative of the power supply the rest of the setup is the same nothing has changed so let me turn it on and show you how the signal looks now as you can see there is now only a single half wave which is the impulse that i want to see that i want to use but you can also see is the little little bump right before the mosfet turns on again let me zoom into that there's a little bump right before the mosfet turns on again and this bump is something i don't understand but this is the impulse that i want to see and that i want to use so there is no ringing anymore and this is because when it turns positive the body diode of the mosfet turns on and conducts the energy into the added capacitor and then the capacitor discharges again when the mosfet is turned on and this is very efficient no energy losses there is no excessive heating all the energy is recycled and reused and a powerful unipolar impulse is created but this cannot be applied to the radiant harvest circuit as it has two mosfets so now we have seen that we can produce a single impulse and that's really nice but this solution with the capacitor can't be done with the radiant half bridge because now the l1 coil is in between the two mosfets and we still have those body diodes like so so now when that l1 coil starts ringing when it starts ringing with the positive first so this cycle then it can pass through this up to here and to solve this i placed a blocking diode like so over here but i can't place a capacitor here because that will take that voltage of the first impulse and will store it and then i would have no capacitor at all the same is when we switch the other mosfet then the resonance will start negative and then the negative voltage will pass through the other body diode go down and to here so then i place a diode in reverse over here but still i can't get a capacitor there so it is not functional and i have tried to come up with a solution for this but there is no solution for this at least not as far as i can see it maybe somebody can see it but i can't see it right now [Laughter] and now for something completely different so the radiant half bridge circuit doesn't work as expected luckily all the work i put into it was not a waste as this circuit is able to simultaneously switch two mosfets in series and that is awesome i love how this came to be i worked very hard to get the radiant half bridge circuit working and then i suddenly realized it could also be used to switch mosfets in series there it suddenly was on my workbench without even knowing i had solved the challenge so to be clear i will not be using the radiant half bridge circuit anymore instead i will use that pcb to switch to mosfets in series let me show you how that is connected [Music] now we have this flawed circuit design now we can fix it to make it into a working design again because now we still have the two mosfets in series and switch them simultaneously these squares are the gate driver ics and they are giving the same signal 50 duty and that way they will turn off and on simultaneously very fast and this makes it able to switch a coil here again on the bottom we still need a blocking diode over here just one is enough and then we put a capacitor over it again as before to store the energy again and then with this setup using the pcb of the radiant half bridge circuit we can create very negative impulses of minus 3 500 volts as i have shown you before because all the positive energy of that transformation all this energy is then again passing through the body diodes of the two mosfets in series is being blocked by the diode over here and then it is stored inside of this capacitor and then when the both the mosfets are turned on again then this capacitor is discharged over the l1 coil again and the energy is reused so it's very efficient again and that is what i'm using right now so here we have two pcb boards of the mosfets this is the one i published and this is the one i now use they are both basically the same so the radiant half bridge isn't useful what needs to be done to make this useful is make it into a series switched mosfet board and to do this you remove the diodes from the board and what you do is you place another connector there where the diodes are so you have another hookup place on the source and the drain this is for the l2 coil to be hooked up in parallel to the mosfets so you need another connector here and another connector there and what you need is to forget all about this in the middle in between the mosfets you don't need this connection anymore so you just forget about it don't use it that's it furthermore let me show you with this circuit board that is based on the c2m mosfets what i did is hook up this coax to the board this red one is coming from my signal generator and as you can see it is split into two signals that feed into the gate driver ics as you can also see i placed another connector here another connector here so here the positive of the supply comes in and that is this extra addition here is that capacitor that captures the positive impulses of l1 that pass through the body diodes of the mosfets so they are coming into here and they are captured in this capacitor which is grounded and connected to the power supply and then we have the diode i have two diodes in series so the positive half wave that passes through the body diodes is blocked by this diode and then it is stored in that capacitor bank which are four times one microfarad 100 volts wema fkp2 capacitors in parallel four times and yeah that's about it that's how this all works i placed the fans on the mosfets again because the energy that passes through the body diode makes it heat up a little bit and the more the mosfet stays cool the better it switches this is how you make it work it's a small modification and then you are able to switch very high voltages and produce very high voltage impulses like what i'm doing here is 3.5 kilovolts maximum and uh yeah for to me it's a very uh impressive i'm very happy that i'm able to do this with this beautiful designed circuit board my youtube channel has almost reached 10 000 subscribers which makes it possible to link merchandise to this channel and i was wondering if you would be interested in that and if so what items would you like let me know in the comment section below please hit that like button subscribe and if you wish to fund my open source research you can leave a donation on my paypal account which is listed below this video that's it for now thank you for watching and see you next time

Channel: Master Ivo

Views: 3,343

Keywords: Dielectric field, magnetic, field, field theory, bifilar coil, bifilar tesla coil, resonance, tesla coil, nikola tesla, dielectricity, impulse, electricity, radiant, research, half bridge

Id: bl4xk8CMe8I

Length: 20min 28sec (1228 seconds)

Published: Sun Jul 04 2021