DIY Turbopump Controller

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ArkadiuszGibes
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Re: DIY Turbopump Controller

Post by ArkadiuszGibes »

Hi

Here is a repository with kicad files: https://gitlab.com/arkadiusz.g/turbotronik1.0hw/
However, that was the first version of this driver, so it has some issues. One of them is LDO regulator, there is to much current that goes trough it and it is getting hot quite fast. I replaced it with Chinese dc/dc reg and it's fine - this is not updated in those pcb files.
This is a dc/dc converter that i used - https://allegro.pl/oferta/modul-przetwo ... 7563986495,
Also, as i built in on top of someones else code, it is using lcd that is driven by i2c -> parallel IC. From what iv'e seen, sometimes it was crashing so I had to repleace it with other type of lcd in my case.

Would be nice to update those files with DC/DC instead of LDO, and rebuild it with standard parallel interface for LCD so it could be used with cheap 2x16 displays. I can do this in free time, but feel free to do any modification you like.

Nikodem, I see that you are from Poland, if we would fix those "bugs" somehow then we could send it to production to china, and share some costs for pcbs.
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Nikodem Czechowski
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Re: DIY Turbopump Controller

Post by Nikodem Czechowski »

I will download the files tommorow and try to do the updates you have mentioned.

What pump you would want to drive it?

We can share the costs, I would ever need 10 pcbs for that - PM me and we can discuss the details.
ArkadiuszGibes
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Re: DIY Turbopump Controller

Post by ArkadiuszGibes »

Right now im playing with turbovac 50 pump, but it's damaged and i ordered turbovac360V. I will need to do some changes because TMP 360V works on lower voltage and frequency, but this is in most stuff that can be done by FW modifications. I will also repleace my 200V dc/dc converter to toroid transformer. Please shere the files when you update them.

Thanks
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Hi Akradiusz, thanks for the links and files. If I could ask you to introduce yourself on the welcome forum it'd be a big help. The rules the old timers have setup here really help to preserve the quality of information on the forum!
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Re: DIY Turbopump Controller

Post by ArkadiuszGibes »

I already did it.
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Oh geez, I'm super sorry, missed that!
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Re: DIY Turbopump Controller

Post by John Futter »

Nicolas
I have looked at your circuit
I did not use a micro directly to generate the drive frequency due to the danger of a reset or port hang from it.
There is a huge amount of stored energy in a turbo that is why in my diagram it was driven from the 4046 being used as a voltage controlled oscillator through a low pass filter that delayed abrupt voltage changes to the 4046. This filter should be changed to suit differing turbos ie longer time constant for 150 and 360 model pumps. Of coarse you change the buss rail voltage to suit these bigger pumps ie 14 / 28 volts for the tmp 360 and higher current mosfets and dont forget to lower the zener voltage in the buss protector
Fusor use includes high voltage power supplies and there will be the odd high voltage flashover that may reset your micro.
I certainly would not direct drive from a micro a larger turbo than the tmp50 due to the stored energy being released.
Even our turbo controllers have had the PSOC reset and the pump scream to a stop ( that what the big mosfet is for across the DC buss so that the electronics is saved from overvoltage from the motor back emf
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Thanks for the clarification John, I think I've misunderstood something fundamental about the operation of the circuit. I'm going to have to digest your post and look over things.
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Re: DIY Turbopump Controller

Post by John Futter »

You are doing alright I'm just giving a bit of sage advice learnt from doing wrong it in the first place

ask away and i'll answer
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Hi John

I have a TMP 50 so I'm dealing with one of the smaller pumps. But my general understanding of the circuit is that you use some discrete logic to generate the signals which drive the half bridge connected to the 3-phase motor of the pump. I had assumed that hooking up the microcontroller to the logic chips you'd used would have provided enough of an innate buffer to prevent damage to the microcontroller. Looking at my circuit again and your comments I assume the problem is with the current measurement portion of the circuit correct? I expose the microcontroller to large changes in voltage/current at that point. If I included some sort of opto-isolation on that connection would I avoid the problem? I've never used opto-isolation in a current sensing application before.
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Re: DIY Turbopump Controller

Post by John Futter »

Nicolas
It is hard to use linear optos to get volt and current sense across I make sure that there is series impedance then 5 volt TVS diodes across micro I/O pins

my comments were directed at some of the other posts where micro derived drive signals are use to drive the half bridge directly
a TMP 50 has about the same energy as a .22 LR cartridge where as a TMP150 is more like a .308 cartridge amount of stored energy
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Thanks for the clarification John, I've added the suggested circuit protection, now I just have to spec everything and layout the board! That's a nice way of thinking about energy as cartridge size, it's been awhile since I've been on a range but even though .22 LR is small I wouldn't want to be hit by either.
Michal Dvoracek
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Re: DIY Turbopump Controller

Post by Michal Dvoracek »

Hello,

I'm finally built up my turbo controller which is inspired by John's but it also contains speed measurement control.
I'm attaching some photos and video is here: https://youtu.be/OWJsfk7cNfQ

Regards,
Michal
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IMG_20210421_025330.jpg
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IMG_20210421_025408.jpg
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Re: DIY Turbopump Controller

Post by John Futter »

Excellent
looks similar to mine. I could not post the digital controller as it was code written at work hence ip problems ..

But well done
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Richard Hull
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Re: DIY Turbopump Controller

Post by Richard Hull »

Michal, a true love's labor and a grand win. I applaud both your and Nicolas' effort in electronics. I call it the hands on imperative or a "doer", doing. The epitome of the thrust of this site and of real amateur science is obtaining and retention of hard won skills that not only make life more full and rewarding, but in the making of a whole, capable person. You can be proud of your effort, you have earned the right to pride of accomplishment. Also laudable is the aid offered by John Futter and others in the quest.

I am sure that all here realize this is but a micro win in a demanded technology, (obtaining a scientific vacuum), along the road to the fusor and fusion quest here. One must never underestimate just how tough, costly, and demanding this amateur effort is to one's time and purse required for the acquisition of both knowledge and materials. It is not for kids. Big boy pants are needed if this task is taken on by any individual.

In the end, a win is laudable, but a win with useful experiment applied to the win is the ideal.

Note: the pep-rally is over. You can all get back to it....

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Very nice Michael! Would I be able to see your code and schematics? Always interested in seeing how problems I have to solve were solved!
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Just a quick update here. I've specced all the components for the Turbopump controller over the christmas break and now I'm getting in to the PCB layout. Lots of little details left to work out!
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Dennis P Brown
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Re: DIY Turbopump Controller

Post by Dennis P Brown »

Extremely impressive; your own design (yes, inspired by John's)? This is rather advanced level electronics driving a turbo - they are not simple motors. This is EE level work. That doesn't even cover the actual execution/build you've done.
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Thank you for the compliments Dennis, I still have to get it to work! The circuit is John's design, I've added a microcontroller to run the whole thing, but that's it.
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

I've completed most of a first draft of the routing of the board. I can post the KiCAD files if anyone wants to take a look but some details still need work. This is the first time I've routed a 4-layer PCB and a board of this complexity. I'd appreciate any constructive criticism more experienced hands might have to offer.

1. Is there a rule of thumb for controlling trace size given the power running through them? I've made the traces going out to the motor much bigger, but I have 5V, 15V and then motor power traces all running on this thing, and I haven't changed either the 5V and 15V traces
2. For a 4-layer PCB I've made one of my planes the ground plane, and was planning on making the second some sort of power plane. I assume I should make it the power plane for the power traces supplying the motor, is this correct? Or should it be the 5V or 15V power plane?
3. Is it generally acceptable to put component labels inside the outline of a component? I'm having trouble getting all the labels to be visible.
4. How do I size vias for different trace sizes, so far I've just been using the default settings in KiCad, but that clearly won't work for my thickened high power traces
5. Any general constructive criticism about the layout of the board and the traces would be much appreciated!
pcb.JPG
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Joe Gayo
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Re: DIY Turbopump Controller

Post by Joe Gayo »

Saturn tools for trace calculations ... https://saturnpcb.com/saturn-pcb-toolkit/

Think about where the high current loops are and make those as tight as possible.

The power plane can be split amongst multiple voltage rails.

There is an excellent video on PCB layout about how power actually travels in the dielectric space. https://www.youtube.com/watch?v=ySuUZEjARPY
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Thank you Joe, lots of good stuff to work through and learn! That PCB layout video is fantastic! I'm only a 1/4 through but so far it's been hugely enlightening.
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Re: DIY Turbopump Controller

Post by John Futter »

Nicolas
that looks pretty good
ie no input lines to micro going anywhere near the 3 phase output driver
you will see that the motor peaks at about 1 amp during rampup ie a hundred odd watts and with no gas load settle to about 6-11 watts at full speed.
have fun
oh and if it turns the wrong way interchange any two of the 3 phase outputs
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Nicolas Krause
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Re: DIY Turbopump Controller

Post by Nicolas Krause »

Just a quick update on the progress of this controller. I've received the first draft of the PCB in the mail, and had built up nearly the complete board before discovering a couple of errors which means I'll have to do a second revision. They are as follows:
  • Double placed one footprint (see if you can find it!)
  • Polarized capacitors are packed too tightly, I cannot place all 5 with the current footprint layout
  • Holes for a diode bridge are incorrectly sized and the component does not fit
I've got a little cheap hot air setup here, so I figure I should be able to salvage all the bits without too much trouble.
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Re: DIY Turbopump Controller

Post by John Futter »

Drat
comes to mind
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