IGBT Driver – Out With The Old, In With The New (Year)

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IGBT Driver PCB

First off, happy New Year! I hope that everyone is doing well in 2018. The first batch of¬†IGBT Driver boards (Hybrid Driver v1.3) from PCBWay came in today, and they look great! ūüôā

IGBT Driver Old And New - PCBWay

PCBWay Manufacturer

This¬†order was my first time using PCBWay¬†and I am blown away by how seamless from end to end the entire process is! I love the technological process tracking, it’s funny, but it reminds me a bit of how some pizza places track the progress of your pizza. My order was accepted, manufactured, shipped and in my shop in no time at all!

The quality of the boards, through-hole plating, silkscreen, bottom side tinning, and everything is a definite A+. I received excellent communication and engineering cooperation from the beginning. Although there are other PCB manufacturers that I like, I am going to use these guys going forward!¬†I’d recommend¬†them for prototyping or production.

PCBWay Technological Process Tracking

Open Source Advocate

I especially like that they encourage open source projects by allowing you to share your board designs, schematics, and project details after ordering. Here is the Hybrid Driver v1.3 in PCBWay’s project sharing section. ¬†They make it easy for others to order¬†boards since all the Gerber files are already there and pre-approved. They even give a 10% back to the project creator. Check it out and take a look at there projects, there are some impressive ones. I like OpenReflow, a control board to convert a simple toaster oven into an accurate¬†reflow oven for soldering SMD components.

IGBT Driver

The new driver boards look great. I like the high gloss black solder mask and the highly visible white silkscreen over it. The slots for the IGBT gate connections turned out great. The board edges are clean and completely burr free.¬†The only mistake I’ve found is that I forgot to set the OSH logo font to vector, so it expanded a bit and overlapped the G2 silkscreen. I also tweaked a few device¬†name¬†silkscreen¬†positions to improve visibility.

IGBT Hybrid Driver v1.3

I’m waiting for the bulk orders of the¬†VLA106-15242 isolated DC to DC converters and the M57962L gate drivers. After that, I’ll stuff the boards and get them in the ReactorForge to continue refining the firmware.


IGBT Driver Stuff Board

The First Kit

I’m planning on making the IGBT Driver (Hybrid Driver v1.3) the first complete kit. Of course, it will be standalone, apart from the rest of the induction heater. I’m ok with having the major components of the induction heater available individually as well as part of the whole machine kit.

I have never made a kit like this, but I am entirely confident¬†that I can put together a great one. Still, this will give me the chance to test that confidence on a smaller scale. I’ve already established a supply¬†chain for the parts and the PCB. What’s left is ordering consumables such as antistatic shielding bags, labels, and packaging. Then,¬†of course, the written¬†plans or instructions for the kit.

Development Environment

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Development Environment

If you follow the GitHub repository¬†https://github.com/ThingEngineer/ReactorForge by clicking [Watch] you may have noticed work on the firmware. I’ve begun setting up the new development environment. Going forward, I don’t want to deal with switching to Windows to work in AVR Studio. I never liked that environment anyway. I had talked about possibly moving everything into the Arduino environment because of its popularity, however that has its own set of issues. For starters, support for the AT90PWM family of chips isn’t there, and I don’t want to spend the time to add it. Then there’s this:

https://atom.io + https://atom.io/packages/platomformio = frickin awesome

Beginning Development Environment

Arduino is a great prototyping platform and IDE to get started on if you have never worked with microcontrollers. As a beginner, it can get you building projects faster than any other platform out there. But eventually, the features that make it convenient and easy to use can hold you back. It lacks many features which make writing code quicker, easier, and have become quite standard in modern text editors. There are also bits of code that get inserted into your code that can cause some very head-scratching issues.

Moving Beyond Arduino

The next logical step is to leave the Arduino IDE behind. We do that by working in a more fully-featured development environment. Atom + PlatformIO is my new favorite open source cross-platform IDE. It even comes with the Arduino framework among others. That lets you test drive it with a code structure you are familiar. When you are ready, you can remove the training wheels and go full native C++. There is so much more I could brag about with both of these tools. But I’ll let you discover the awesomeness yourself!

Development Environment

Next Steps

What’s next? I’m going to begin porting over the libraries used in the existing project. Then the main code, and¬†start rewriting, optimizing, etc. The photo above is a test rig I used for setting up the new IDE. I will continue to use it throughout the porting process. Once the code is stable in its new environment, I’ll switch over to the ReactorForge!

I had also planned on using this setup to demo and explain the basics behind the AT90PMW software PLL setup. I’ll get to that but for now, it’s back to work in the new development environment!

Patreon Charges and 260 Pound Parts Delivery for IH Kit

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Patreon Charges

There has been a lot of confusion created by they way Patreon charges its patrons and paying creators. You can find the official information can here: https://patreon.zendesk.com/hc/en-us/articles/115005631963 And here is another excellent article on the topic by TechCrunch.

TLDR; The short version is, Patreon moved its credit card processing service fees from the creator to the patron. Because of this change, Patreon was able to lower the overall fee amount and give more to the creator. The fee amount is (2.9% + $0.35) for each monthly pledge.

Because I have worked on unique e-commerce projects, I understand the intricacies and complications of bulk credit card processing, multiple payees, and the associated charges and chargeback liabilities. However, I do not support Patreon’s decision, and I firmly believe there is a better solution. Because Patreon is a goodwill engine, I think this move is, for lack of better terms, just weird. In addition, I won’t personally be canceling any of my Patreon pledges. Nevertheless, as a patron myself and now a fledgling creator, I do hope that we see these processing fees moved back to the creator.

Other Support Options

Your support is much appreciated, but entirely voluntary. You may continue to¬†make a small donation to support the project and website using Patreon. If you decide to cancel out of principal, I understand entirely. If you prefer I’ve added a PayPal button on the pledge page “Coffee” to enable you to make a small reoccurring monthly pledge that you can change or cancel it at any time.


Support the ReactorForge via PayPal



Or you can send a one-time pledge. Please include a note to let me know it’s a gift and what made you decide to support ReactorForge!




I may add members only functionality to the website¬†linked to Patreon PayPal as well, to mirror and even enhance the capabilities Patreon offers. But I’m not sure there is indeed a need for that yet, or possibly ever. Thank you all again for your support, be it monetary, intellectual, or constructive criticism. I value all of it!

ReactorForge Parts Delivery

I just received the first shipment of parts for building more ReactorForge induction heaters, 258 pounds worth. This component is of one particular importance and one I have settled on despite other possible changes I will be making to the design. Anyone care to take a guess what part this is?

ReactorForge Induction Heater Parts Shipment ReactorForge Induction Heater Parts Shipment

Mains Power Feed Complete

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Mains Power

This is the last mains power update for the ReactorForge Induction Heater. It will be the last because it’s complete! Here is how the last couple days of that process went.

Mains Power

I started by connecting the jumpers from the custom splice connector to the 60 Amp 240-volt dual pole breaker and ground bus. The photo shows green hooked to the neutral bus. I later moved this as I did not need to tap 120-volt like I thought I would have to since the ATX power supply runs on 240-volt now. (I just forgot, it’s been a while.)

Mains Power

And here is the 240-volt quick disconnect assembly installed and ready. I will print another version of the slide lock. The slides should be solid so the splice connectors are not accessible while the wires are disconnected.

Mains Power

Next, I prepared the 2 AWG mains power feeder lines. These will connect the splice block directly to the input of the ReactorForge.

Mains PowerMains Power

The splice block side has thick metal tabs that are double layered with heat-shrink tubing. These provide a high current, high durability connection to the screw terminal that will stand up to multiple connect/disconnect cycles.

Mains Power

The Induction Heater side has heavy duty lugs that will accept the terminal post. These are also insulated with double layers heat-shrink.

Mains Power

Bringing It All Together

And here you can see the feeder lines connected to the input of terminal posts on the back of the ReactorForge. I also ran a USB extension with a small hub for connecting the Atmel ISP programmer. I put the Bluetooth dongle here as well. It communicates with the mainboard to send/receive commands and system telemetry.

Mains PowerMains Power

I then installed a variac between the mains contactor and the inverter input filter.

Mains Power Variac

When software activates the contactor, 240 volts directly feeds the inverter typically. Since I have a decent amount of testing to do, I severed that connection and installed the variac to allow lower power testing.

Mains Power

I taped up the small areas where 240 volts was accessible in the front to avoid accidental contact or tools shorting things out. Getting my fingers across 240-volt mains power is not something I want to experience twice!

Mains Power VariacMains Power

On To The CODE!

That’s it for cooling and mains power connections. The next step is to get the programming environment set back up. I will turn things up as is and do some testing to make sure everything is still good. Once that is done I will get right to the next big task, I’ve decided to port the entire thing to Arduino. This won’t be too difficult since the code is already in C and I will be glad to get away from AVR Studio, to be honest. I made the choice to move to Arduino due to is massive use and rise in popularity over the last few years. Since this is an open source project I want to use a platform that people are familiar with. Let’s put industrial level induction heaters right up there with open source 3D printer firmware!

PSA – Net Neutrality – README

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Net Neutrality

Don’t silence humanities most successful form of communication!

Despite¬†what country you live¬†in¬†the topic of Net Neutrality once again affects you. I will get back to updates and work on the ReactorForge Induction Heater tonight, but this is a pressing issue, and we should all be very concerned. More so than concerned¬†we should be active and involved. Voicing your opinion requires only minimal effort. If you don’t have an opinion or have never even heard of the issue, don’t just repeat someone else’s. A¬†quick google search of “Net Neutrality 2017” will help explain the problem. Yes, do include 2017, because this happened already, back in 2015. The following paragraph is my synopsis and view on the matter.

Net Neutrality 2017

I rarely voice my opinion publicly on political matters but hear me out. Our policymakers disgust me. Despite the fact that both parties support net neutrality, they yet again go against our voice. The internet is by far, the most successful form of communication humans have ever invented. We can not give away control of that medium to entities who would redefine it for their financial gain. ISPs or any corporate entity for that matter SHOULD NOT be in control of Internet services. Internet traffic should be treated equally – email, files, web content, can’t be blocked, slowed or discarded by ISPs. I hope our state reps continue to back us up. Call, Facebook, Twitter, and or snail mail your rep!¬†https://www.house.gov/representatives/find-your-representative

Nylon 3D Print of the 240V Quick Disconnect

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3D Print 240V Quick Disconnect

In my last post, I showed a prototype 3D print of the 240V Quick Disconnect. Here are the results of the final 3D print.

Nylon 3D Print

I’ve got the final version of the 240V Quick Disconnect printed in¬†in natural colored Bridge taulman3D industrial high strength nylon. It is insanely strong! The first nylon 3D print failed because I forgot to include a skirt, so the edges curled up slightly, and I didn’t notice until it was complete. It still worked, but it bothered my OCD, so I reprinted another, only took an hour anyway. I ran over that first nylon print with my truck (laying flat), and it didn’t get so much as a scratch on it.

The slide lock completely prevents finger access to the Burndy splice connectors. Still, this is not something you should attempt if you are not familiar with electrical safety and codes. Your best bet is to higher an electrician¬†to add a permanent outlet. This¬†assembly setup is for testing purposes only, and I know what I’m doing. Don’t try this at home.

Safety First

Things you should understand if you do try this at home is the earth ground system in your home electrical wiring. You should also understand how NOT to overload circuits, that’s a significant fire hazard. The NEC can help here understand load maximums on a given wire gauge. Finally, understanding how transformers isolate you from the shocking truth will help you understand how the work coil is electrically separated from your home or shop AC grid.

Remember, Safety should always be first! The voltage and current coming from your wall outlets can kill and should always be respected.

Project ReCap and Photos

The updated CAD 3D print files are on on the Thingiverse Project. This assembly houses 3 Burndy splicers (PN: AMS2BAG2R). It does a few important things, it isolates them from each other, from the breaker box, and it snaps closed to prevent the lugs from sliding out (and attacking passer buys). On the side where the wires enter the assembly from the breaker, it is closed off except for holes just big enough for them, so it’s impossible for the splicers to slide out from that side. There are also ears on the front to keep the entire assembly from sliding all the way in the breaker box.

Power Progress – 240 Volt Quick Disconnect

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240V Quick Disconnect

In the photo below is my power test setup at home. Unfortunately, where my other shop is right now, I am unable to make changes like this. Here I explain what I did to get around that and make power progress!

DIY Induction Heater Power

Now that the ReactorForge is back on the bench it’s time to get it powered up!

This¬†setup isn’t necessarily something that an inspector would like to see. ¬†So don’t think this is my recommendation for a permanent solution. I’m just sharing what I did to make my current setup work. Keep in mind the breaker should always be OFF before connecting or disconnecting wires on the quick disconnect assembly.

To hook up 240 to the ReactorForge in this shop I have to run a temporary line. I don’t want to have to remove the breaker each time I do this, so I made an enclosure that mounts in a breaker slot. The assembly houses 3 Burndy splicers (PN: AMS2BAG2R). It does a few important things, it isolates them from each other, from the breaker box, and it snaps closed to prevent the lugs from sliding out (and attacking passer buys). On the side where the wires enter the assembly from the breaker, it is closed off except for holes just big enough for them, so it’s impossible for the splicers to slide out from that side. There are also ears on the front to keep the entire assembly from sliding all the way in the breaker box.

I printed a quick test in PLA, made a few changes and am ready to 3D¬†print the final version in nylon after Thanksgiving. I’m sharing all the files here in case anyone else finds it useful. Be smart, be safe.

Power progress photos:

New Shop Power Panel

My problem is that I do not want to open up the panel and remove the breaker and wires every time I need to remove the temp line.

Power progress

Fusion 360 power splice quick connect

So I drew a simple small enclosure to house some common splice blocks made by Burndy.

The prototype:

 

The slide lock action:

Technical Drawing:

240V Quick Disconnect Drawing v10.pdf

*Tip: I usualy try to make a technical drawing before I 3D print a part. It’s quick and easy in Fusion 360 and saves me wasted prints and time redrawing later. I always catch a lot more looking at the drawing with multiple views and mesurements than just looking at the drawing in the viewport.

You can view and download the CAD files over at Thingiverse –¬†204 Volt Quick Disconnect Splice Housing¬†

ReactorForge History – A brief history lesson 01010010

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ReactorForge History

There were many before it, after it and in-betweens, but these are the milestones! This is a brief ReactorForge History lesson.

ReactorForge History

From left to right.

  • The first MOSFET version on a PCB. It worked great but didn’t couldn’t handle the power level I wanted. I ended up pushing it to failure and moving to brick IGBTs.
  • The first IGBT version on a PCB. This design is based on a CD4046 PLL and uses gate drive transformer to drive the large brick IGBTs (the ReactorForge now uses hybrid drivers). If you are into electronics and you’ve never worked with a PLL, even if just on a breadboard you should. PLL’s are very well documented, fascinating little devices. This circuit works great but its frequency operation range was limited by the external passives for the VCO (voltage controlled oscillator). Due to its reliance on these passive components, it is also affected by temperature.
  • For mainly that and a few other reasons I decided to explore a software PLL solution. After going around the usual suspects and understanding how a PLL worked I thought there must be some way to do it with a low-cost MCU, not a freaking FPGA or high power processor. Maybe some type of PWM/comparator combination I thought. I found my solution in a motor controller, or power stage controller chip made by Atmel, the PSC216,316 microcontroller. That’s what this breadboard is, the early testing for what is now a rock-solid way to find the resonant frequency (Fr) and adjust power levels by offsetting that frequency from the current Fr all while soft switching (i.e. not making heat in the wrong places and exploding electronics). This was the result of those early tests…

ReactorForge History - Current

The Future:

One more board redesign may be in order but we’ll see. I may look into reducing the size of the board down the standard Eurocard PCB size of 100mm x 160mm. Although the current size is still within the free size limit of 160mm^2 for Autodesk Eagle.

That was the¬†ReactorForge History, now let’s forge ahead to the future!

Reactor Forge on the Bench

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Reactor Forge on the Bench

The Reactor Forge on the Bench and ready to hook up!

Reactor Forge on the Bench

This new rolling stand from SAMs club was perfect for holding the Reactor Forge, Bernard Weldcraft 3 gallon water cooler, extra bricks, and coils. I just need to replace the top plastic insert/mat with a piece of sheet metal. 

High-level action plan:

  • Publish existing mechanical specs, unit wiring schematic, core control board schematic, to Atmel C code to Github.
  • Add my current issues and changes that need to happen to each of the above topics in Github for proper tracking.
  • Work on those issues, changes, and improvements.
  • Make the next version, test, refine, and repeat as needed.
  • Work on BOM supply chain.
  • Kit logistics: work on which parts will be preassembled and which will require user assembly.
  • Create and publish a kit manual.
  • First test kits for¬†users, feedback, etc. etc…

What’s next after getting the¬†Reactor Forge on the Bench?

Hooking up cooling water and power.

Induction Heater Price what is your target range?

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Induction Heater Price

I want to get a better idea of what a machine like this is really worth to you. I’m doing this in an effort to ensure that the additional work I’m about to put into this project to transform isn’t in vain. Because an induction heater price can vary wildly and to go from DIY induction heater to a kit or production unit is a big leap.

I will be completing this project and making it open source regardless of whether or not making a kit is viable. But before I do go down that path, to kit or not to kit, I’d like to know what it’s true value is.

To give you something more concrete to evaluate use the two videos below to get a rough idea of the capabilities of the machine as it relates your needs and use these technical specs.

Reactor Forge Induction Heater Specs:

  • Simple interface and usability
  • Operating Voltage: ~220V
  • Maximum Current Draw: ~40A
  • Typical Current Draw: 10-30A
  • Power Factor of near .99% (You won’t find that in a cheap overseas model!)
  • 100% duty cycle
  • Water cooled (cooler not included but it can be as simple as a garden hose attachment)
  • Mid-range frequency operation best for small to medium size workpieces. (Lower frequency is possible for larger items above 5-6″ cross section at lower power levels.)
  • Remote foot switch operation
  • Simple to complex programmable cycles
  • Many safety features
  • All digital operation (so performance is not affected by the environment)
  • A fully sealed case for protection against debris and dirty shop air.
  • Hackable! Many future improvements possible such as workpiece temperature feedback for reaching very precise temperatures.

Videos of the current Reactor Forge, Critical Mass in use:

https://youtu.be/C8s0zIcqVfk

https://youtu.be/4vICz4akL6k

So what is your target induction heater price?

Please check out the full post and Poll on Patreon to cast your vote: https://www.patreon.com/posts/15375592

Induction Heater Price

Also, check out The ReactorForge Origin Story to learn more about how this project got started.