Resources:
Build & demo video: Click here
Coil form tool Download STL file
PCB Gerber files Download gerbers
Schematic Download Schematic
Details:
Voltage input: 12~48VDC
Current input: up to 30A (@48VDC)
Peak power input: 1,400watts
The Circuit
This induction heater is based on the popular "Royer induction heater" schematic. I believe this is the original post/author? Click here
Changes made to the design include:
Higher rated MOSFETs
Bigger Zener diodes
RC filter on the Gates
Flyback Diode (D8)
Gate resistors to limit ringing (R8, R9)
In short, all of the changes help to improve the durability of the induction heater. It has been reported with the original design, often the MOSFET gate's would be damaged from flyback after extended use. To be fair, I haven't tested the circuit without my additions so I can't confirm or deny this. Gate resistors have to be added as ringing was quite a problem without them. The ringing would cause the MOSFETs to become quite hot & this can lead to premature failure. With the addition of a pair of 18R gate resistors. The ringing was reduced to an acceptable level.
Components:
2x Wakefield-Vette, 694-50 Heatsink Click here
2x IRFP4668PBF MOSFETs Click Here
10x WIMA, MKP1J034706B00KB00, 470nF, 630VAC Capacitor Click here
2x 2.2uF Ceramic 100v Capacitor Click here
2x FR307 Fast Diode Click here
2x 47R, 5w Metal Oxide resistor Click here
2x 470R, 5w Metal Oxide resistor Click here
2x 12v, 5w Zener Diode Click here
1x SB5H100 Schottky Diode Click here
2x 100uH, 15A inductor Click here (see below for details)
2x 10k, 1/2w resistor
1x 4.7k, 1/2w resistor
2x 18ohm 1/2w resistor
1x 5mm LED of your choice (power indicator LED)
The inductors
For the inductors, I opted to wind my own. Options for this size are somewhat limited & it was cheaper to make my own anyhow. If you don't wish to make your own, then alternatively you can buy them from banggood Click here
Toroid details:
Size: 42x22x17mm
Material: Iron Powder, HY2
Color Code: Yellow/White
For the wire, I used 1.25mm (16AWG) enamel insulated copper wire. Each toroid used approx 1.6m (63inch) of wire. This length of wire yields 30~32 turns around the toroid giving an approx inductance of 100uH.
Tinning the high current traces
Located on the underside of the PCB is several exposed traces that should be tinned with PLENTY of solder after all the components have been installed. These traces carry very high current that pulses through the work coil. Failure to adequately bolster these traces with copious amounts of solder will result in the solder melting off the PCB, which will result in the trace burning out, which in turn blows up one of the MOSFETs (not that I'd have done anything like that :P )
I'd recommend laying down some fairly heavy copper wire on top of the traces & solder it in place just to be on the safe side.
The Coil
This is the work coil. I made my coil from 3/8" copper tubing (the type used for aircon, fridges.etc) It's pretty inexpensive & easy to find at most hardware stores or aircon shops. The inside diameter of my coil is 70mm to accommodate almost anything I'd need to heat.
The coils consist of 6 & 1/2 turns. The amount of turns does play a role in determining the resonating frequency (and also power output/consumption). If you know what you are doing & are willing to experiment with different coils, then go for it. Otherwise, I'd suggest making a coil with 6~8 turns.
If you watched my build video, then you'll have seen me 3D print a form tool, used to wrap the copper around to form the coil into a spiral. Strictly speaking, It's not essential however, it does produce a nice uniform coil. You can download the STL file Here
Performance
With a 48V power input and a 140mm PC fan blowing air over the heatsinks & caps. Temperatures were quite acceptable at 80c (176f) for the MOSFETs, the capacitors were about the same. And the inductors never felt even slightly warm. I think for higher input voltages (above 48VDC) You'd have to start considering spacing the caps further apart for better cooling & depending on how far you push the envelope.... maybe water cooling the MOSFETs & work coil.
Will it melt Aluminum?
The original author demonstrates his induction heater melting an aluminum heatsink. I've attempted to melt alloy in my induction heater and it failed to do so. I'm not exactly sure why he was able to melt alloy and I was not but, I do wonder if he is tuning up his power input to achieve this? He seems to indicate this in his post. It's also possible different alloy's melt easier than others so perhaps this is something I'll explore later.
What would it take to make this induction heater more powerful?
In truth, the components used could probably handle 60V (just monitor the peak voltage across the caps & make sure to stay within their max voltage rating). However, at higher power levels, you certainly need to bolster the high current traces on the PCB to prevent failure. Keeping the caps & MOSFETs within temperate limits could also be a challenge. Perhaps water-cooling would be a viable solution? In any case, it's certainly possible for this circuit to handle higher voltage than 48VDC if appropriate measures are implemented.
Man, I made the same schematic, made a new PCB, get it ordered. But, it does not work (does not oscillate). I tried Ltspice to simulate the circuit, got a flat line. I have no idea what went wrong and what's causing the issue, can anyone assist?
An aluminum rod that doesn't fill the coil throat doesn't have good heating prospects; either use another
material like a graphite crucible (the graphite heats, so anything inside it, does too), or a smaller-diameter
coil. There's also a 'skin effect' so that at 10 kHz, only about a millimeter of the aluminum conducts; what's the frequency here, 30 kHz? Much less than a millimeter...
Hey! From Canada. Ordered 5 pcbs, parts, assembled one and it works. can't believe it. i am such a noob. Powering with 12v, one mosfet gets hot. i powered the circuit once for .5 seconds without the induction coil. Bad?. i have 4 more to build. haha. thank you so mucho. I need to heat up 16mm steel rods to bend them 180 in a short radius. Edit: I made the exact same coil he makes and now the circuit is perfect, no overheating on one side. I have 2 perfect boards now, lets do the 3 others. 7 turns (8 loops when you count them with your finger).
i have the same mosfet but not that 1400watt of power.
what components should i change? or i need to change the circuit??
I will have to experiment. Thank you.
Hi, I know it is an old post, I'm building this circuit to anneal brass and I'm wondering how to find/tune the right resonating frequency for what I need, around 120 Khz.
What's the size of the PCB and how many layer is it.
Shouldn't we use AC supply instead of DC for the induction heater and why?
Does anyone have spare PCB to sell in Europe?
That metal rod you heated up red hot in the video, what safety considerations have you incorporated in this project should you drop the rod onto the coil and shorted it out?
HOW TO BUY PCB
Where can I buy the pcb?
Please send me the PCB drawing by email because I am in a country where I don't have access to buy it, so I have to make it myself.
I've built a annealing coil approximately 19mm ID, two layers of 3.25 turns, 6.35mm (1/4") OD Copper Tubing for a total of 6.5 turns. My LCR meter measures the coil at around 3uh of inductance. I've measured other inductors and the meter seems reasonably accurate. I've built the ZVS Circuit as designed with PCB's from JLPCB (I have a few extras...). My Power supply is a 48Vdc 25A MEISHILE from Amazon and it's set for 48Vdc. As soon as I turn it on, without a case in the coil, it crowbars the power supply off within 10 seconds and has blown 20a fuses on the DC side. The coil is getting very warm, but not warm enough to burn skin. I'm wondering what the coil inductance should be?? 3uh seems a little high, I was shooting for less than 1 because 3uh calulates to 42Khz frequency. Any ideas? Thanks!
I would like to build a case annealer.
Having trouble finding info needed in one place. This really screws with my dyslexia.
Any help is appreciated.
This is a powerfull project am thinking can we use it for cooking in developing countries using solar powe where most people are using biomass especialy wood degrading environment
Hi all,
I see a lot of induction heating projects having input voltages of 12 till 48 volt and it made me wondering. What would happen if you rectify 230AC and rectify this to be used as an input? If this is possible could you then still control output bij PWM?
Maybe stupid question but for anyone willing to answer I would like to thank you in advance.
kind regards,
Mitchell
Can I buy ready one to try it?
These are the mosfets I was able to get, I dont know if they are the correct ones needed.
Hello,
I have a project where I have to produce a certain quantity of heat with the lowest consumption possible. This quantity is quite low, got it @12V and 36 Amps with the appropriated workcoils on a chinese induction circuit. I want to use your circuit because of its durability. Do you think I could get lower amps @48V to reach the same wattage? for example 48V and 9 amp? By designing the workcoil properly?
My main concern being heat dissipation this could make my life more easier 😁
Hey. I had an incident with blowing my mosfets because one of the traces blew apart. Fixed the trace, switched to new mosfets and powered it back on to see no heating at all and then later figured another mosfet burnt... Any ideas? No traces failed this time. I am using the v1.1 heater with 48vdc @ 30 A. This project is taking me a little too long.
I'm having a couple of issues with my version of this circuit. I've had to substitute IXFQ140N mosfets, as the IRFP mosfets weren't available. I believe these should be very comparable.
First, the gate resistors are getting very hot. I turned one of mine brown in perhaps 5 seconds when I first fired up my circuits. Would lowering R8/R9 to 10 ohms perhaps help that, or does it indicate some other issue? I'm going to triple check everything to make sure I don't have anything different from the provided schematic, but I believe everything is exactly the same except for the mosfets.
Second, this circuit is latching my SSR closed, such that my Arduino can not turn it off. Still trying to figure out why. Has anyone else had such an issue? Might be the cheap SSR but I did not have this issue with the cheap Amazon ZVS circuit running the same power level.
I'm considering simplifying the circuit back to the basic ZVS style, just using the more robust components, and then slowly adding back the extra features (RC circuit, flyback diode, gate resistors) to see which area may be causing me issues.
Hi,
I'm going to build 3kW induction heater... any specific PBC used for it.
Has it any name or model to order please.
Many thanks
Can i use it to make hot water boiler.
Pcb board
hello, pleas what's the size of the pcb, i can't find it?
PSU update. We tried to use a microwave oven transformer, but it's not possible to get sufficient number of windings onto the secondary due to space constraints. So today I will be ordering some U cores from Powermagnetics. These are 126mm x 90 x 20 and give plenty of room to wind a custom primary and secondary. We'll feed the output to a full wave rectifier and smoothing. I'll post back with results.
Paul
Hi,
What did you use for the power supply?
Regards,
La Mar
Hi
I tried to simulate your circuit in LT spice, But I get the wrong waveform.
Please check my schematic:
Does this heat titanium and/or tungsten. I am going crazy trying to figure this out. Thanks for your help, and the project looks so neatly done.
which is the link where is the video that shows how the components are connected and solderedLooks like a well made system. I'm not an electronics engineer, just a hobby electronics. If the caps are getting hot a) check their temp with a meter, b) use a cooling fan. If the temp is too high for their rating, they will break down. The cause is the amount of current in the circuit (caps and coil ). It may be possible to change the rating of the capacitors perhaps - need to explore on google etc. I am exploring making a higher power version of this myself, but a higher power version won't work with caps on a PCB> I'll check out some components and report back - caveat I am not an electronic engineer :) It may be possible to change the number of capacitors, but it's a resonance circuit, so if you change the number of caps, you'll probably have to change the number of turns on the coil and back to square one (hot caps). Perhaps Amon might give us some pointers?
Hi, I also made this device, but the capacitors are getting hot. Please solve my problem.
Another interesting idea with the MOSFETS might be to double up each one so that they share the current load. This could perhaps allow for an increase in current supplied to the capacitor bank by upto 2x (in theory), but the PCB might need mods and almost certainly the capacitor bank would need offloading from the PCB onto external copper rails.
Given the current associated with the capacitor bank, would it be useful to offload the capacitor bank into a separate bus capable of handling the current. Perhaps solder the caps to thick copper rail.
Hi this looks really good. Will it heat 15mm square steel bar to a temperature where it can be modelled on a blacksmith's anvil?
Thanks for designing and posting this! I just built one on your PCB and a test at 12 V worked great. Current matched your video, around 2.5 A idle and 5-10 A with a workpiece. Now I need a bigger power supply...
Hi Amon, thanks for such useful projects and clear explanations for us inexperienced electronics newbies. Just waiting for a quote from a local pcb manufacturer here in the UK from you files (thanks again). I’m thinking of making the coil from solid copper bar which I’m hoping I can solder to the pcb and drill to take the capacitor bank, hopefully avoiding the heat issues. Was the tube you used fairly thin walled? Thanks again for these projects
Len.
I did not find any less power
https://ru.mouser.com/ProductDetail/Vishay-Draloric/AC01000001809JA100/?qs=R4%2FAj8xQbdVl8RU3K%2F2%252BNA%3D%3D
Ok, maybe a stupid question, but are the 18R gate resistors just an 18omh resistor and what wattage would it be? Does anyone know where I could find some?
Who knows - this is a normal algorithm voltage sequence? And what should you turn on first? Start or Main? What beads would be better to put on R8 and R9? http://www.amidoncorp.com/small-ferrite-beads/?sort=featured&page=3 Two beads for each resistor? On resistors R2, R5 and R1, R4 is the same desirable? Who's to say? On one of the switches to put on delay timer with relay?
Hmm. Are there any live ludi here? Or I'm in 28 Days Later
You can see it in the photo at the beginning of the post. He is the smallest. There are no conditions. The current through it is minimal. This can be traced to the datasheet of the transistor.
Hello, I am currently building this. I was wondering: what are the specifications for the 18Ohms Gate resistors (R8 & R9)? Cheers and greetings from germany
Johannes
Found the power supply unit RSP-1500-48 Mean well, not new. But the price is normal - $ 84. Well, delivery, 15 dollars.
Keep in mind induction heating requires a ferromagnetic susceptor (whatever is placed in the coil) If you want to heat something that is not ferromagnetic, make yourself a ferromagnetic tube or sheath to fit around around your part. It should fit fairly well since you are depending upon radiation to heat your part with the susceptor. Ferromagnetic means something like iron that is attracted to a magnet.
What was your approximate build cost for this, if you don't mind?
Also- I get that coil as designed will heat steel- how exactly do you determine size of coil for different metals, like you did above for stainless tube? How did you calculate diameter and turns in the first place?
I've wanted one of these FOREVER- this looks actually buildable- thank you so much for posting all this!
Hi, what is the current through the coil at 48V and no load? Trying to figure out the magnetic field it generates.
我做了3个 就一个启振的 ， 另两个死活不启动
Thanks for that! Thanks for the project schematic, I just upgraded my CNC machine and plan on using shrink fit tooling, and needed an induction heater to put the cutting bits into the tool holder. The commercial devices are prohibitively expensive, so this will work out very nicely, very much appreciated.
Hello! Thank you for your work and info on this project. I'm a fan of your channel. I went to download the Gerber files, but the link is the same as the Coil Form Tool. Is there a better link to use?