ZVS Induction heater 2000W 40A 50V - Page 1
Forum section: electronics / projects

author: strawberry
author_rank: Super Contributor
timestamp: March 04, 2017, 01:32:56 pm
content: ZVS Induction heater 15..50V 40A 2kWStanby loss with 6 capacitors: 6A@50VMOSFETS: IRFP4227Capacitors: WIMA FKP4 0.22uF 1000VdcTank coil: D35mm H35mm 5wPCB fabricator: PCBwayPower supply: DPS-2500AB 2000W P-CLASS PROLIANT BLADE POWER SUPPLYhttps://youtu.be/1Z1EJBMwy5QAltium source files :https://drive.google.com/open?id=0BwVLiaRx-ca4c2pJVlhLRmEyNDQCoil :https://www.ebay.com/itm/303569445933

author: bktemp
author_rank: Super Contributor
timestamp: March 04, 2017, 01:50:10 pm
content: Nice design. What does your work coil look like?One neat trick I have seen is using a small mosfet instead of the diodes (D2 and D3 in your design):Connect the gate to 15V, source to the gate of the main mosfet and drain to drain of the opposite mosfet. So the gate voltage follows the drain voltage as long it is below ~13V.Using this method all the gate drive power is derived from the tank circuit. So you don't need any pullup resistor or the addional gate drive stage.The only drawback is, the 15V auxiliary supply must be present before the main voltage is applied, otherwise it may no start up correctly.

author: strawberry
author_rank: Super Contributor
timestamp: March 04, 2017, 03:48:41 pm
content: Cu pipe

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 04, 2017, 08:50:59 pm
content: Cute, but how is it different from the cheap junk one made in China? Is this one safe from exploding when the coil is open or short circuited? Does it have power control? Can it be scaled up to practical sizes (10kW+)?Tim

author: RadioNerd
author_rank: Regular Contributor
timestamp: March 04, 2017, 10:28:43 pm
content: It looks like you are not using any water cooling for the work coil.Can you use it for several minutes without overheating?

author: strawberry
author_rank: Super Contributor
timestamp: March 05, 2017, 09:13:34 am
content: It have new MOSFETs , ultra low loss capacitors, 70um PCB technology, unified heatsink(safty), no need for gate resistors(simple turn on/off), integrated bimetal overheat protection, It all in small 50x160mm pcb form factor. Efficiency increased up to 6A stb. with same konfiguration as chinese 1kW version on ebay.Work coil and capacitors are capable at more power than 2kW, When used all 10xcapacitors heating gone realy fast but coil reached ~400°C in 10s. With 6xcapacitors still it is not useable for several min. I cool it down in water bucket.No it is not protected from short neither power control. It is first such powerfull device made. Because I made it not china.

author: doktor pyta
author_rank: Frequent Contributor
timestamp: March 05, 2017, 04:38:47 pm
content: Few Years ago I built similar device for wireless energy transfer. I found that when I tried to turn on the power supply one of five attempts ended with high current consumption an activating overcurrent protection (10A) of the PS. This is possible when the symmetry in the circuit is "too good". From further investigation it was becausethe two "drain" inductors were not coupled (as a middle-tapped autotransformer)."working coil" has no central tap. I think that making it similar to Resonant Royer topology would make it work more reliable.Maybe someone has better explanation.

author: strawberry
author_rank: Super Contributor
timestamp: March 05, 2017, 05:17:52 pm
content: Interesting drain inductors configuration. I never had startup failure before(at no load).When turning device on with gate power then drains get voltage overshoot.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 05, 2017, 09:56:13 pm
content: Most common failure mode is lack of oscillation leading to massive power dissipation, or gate bias dropping out before drain current, resulting in massive overvoltage spike.This is a current-sourcing circuit, and as with all current sources, it must be commutated by bringing the source to a short-circuit condition. (The source supplying the transistors is the inductor(s), and whatever current they've been charged up to. Discharging these, with a short circuit, while there's a constant-voltage source behind them, is a non-obvious procedure. This highlights another of the fundamental quirks/design issues of this circuit.)Tim

author: strawberry
author_rank: Super Contributor
timestamp: March 29, 2017, 05:08:18 am
content: PCB update

author: BlackTM
author_rank: Newbie
timestamp: May 18, 2017, 07:24:45 pm
content: Hi strawberry.Can you please tell me at what frequency does your induction heater work?

author: james_s
author_rank: Super Contributor
timestamp: May 19, 2017, 12:30:25 am
content: The induction heater I built from a circuit I found online uses a small 15V standby power supply to get it oscillating and then there is a relay that applies full power when activated. Hasn't blown up yet.

author: strawberry
author_rank: Super Contributor
timestamp: September 26, 2017, 06:28:40 pm
content: Quote from: BlackTM on May 18, 2017, 07:24:45 pmIt's roughly 90..100kHz( depends on work coil and capacitors)Quote from: james_s on May 19, 2017, 12:30:25 amMy schematic are the same, but additional gate drive emitter follower gives nice square wave for MOSFET gates.

author: calexanian
author_rank: Super Contributor
timestamp: September 26, 2017, 11:23:38 pm
content: Looks good. I have a couple of those cheap ones from china. I also have a big old lepel RF generator. I have always wanted to modify one of these circuits with a starter circuit that would always ensure a proper start. I think maybe a quick one shot pulse on one side to get it going, or introduce a low level recurring pulse on one side from a separate driver circuit that then just gets ignored once the power devices get going. I have mine connected to a foot switch and an LED riged up when it is running. If the light does not turn on I let up on the pedal momentarily and when I step back on it again it will usually start. I also use a variac to control the power level. Its a nice arrangement. Very accurate. Makes pretty welds in copper pipe if solder paste is used. Fantastic for copper tube wave guides. Gotta use water cooling for that though cause copper is hard to heat.

author: strawberry
author_rank: Super Contributor
timestamp: September 27, 2017, 07:18:51 pm
content: Lepel RF generator is something new for me, is it using vacuum tubes? Do you have schematic?I am planing to build mains powered PLL induction heater. I am aiming on about 3kW power

author: calexanian
author_rank: Super Contributor
timestamp: September 27, 2017, 09:15:43 pm
content: Lepel is still in business. They are owned by Inductotherm now. The unit I have is tube based but they make fully modern types now. Honestly though i just use the ZVS ones now. Less trouble. Ebay is full of old Lepel tube models, but I would advise against them. Once the insulation on things starts breaking down inside they just dont work right anymore and they are truly a pain to rebuild. Way cheaper and easier to build one like yours. There is a classic circuit in the RCA transmitting tube manual for a 833 type tube based one that was popular back in the day. Its very tricky to get the main coil and tank circuit right, but they evidently worked quite well.

author: kelesekrem
author_rank: Newbie
timestamp: October 03, 2017, 06:38:15 pm
content: hi, thanks.I want to use this heater model in 3d printer, can I use it and can go to high temperatures for 600C

author: strawberry
author_rank: Super Contributor
timestamp: October 03, 2017, 10:23:59 pm
content: Do you mean casting metal in 3D printed molds .. Yes it could be possible, by now I have not tried to melt something with induction heater.

author: 3DARTjar
author_rank: Newbie
timestamp: January 31, 2018, 10:20:01 am
content: Thank you Strawberry for sharing with us your project! I would be interested what quantity of nonferrous metal can you melt with this heater in a alumina crucible ? I would like to use it with a AEG SAFT NIFE 50V/34A power supply if it is suitable ?

author: jlkazim
author_rank: Newbie
timestamp: February 19, 2018, 02:50:00 pm
content: Hello I am interested in ZVS Induction heater 15..50V 40A 2kW but now I want to order 20 PCB of this machine and the components how to do?

author: CopperCone
author_rank: Super Contributor
timestamp: February 19, 2018, 05:21:03 pm
content: I wanted to build one with h bridge phase power control. This way you could use a dspic to control both phase and frequency.This seems less parts heavy then designing a high power adjustable supply for the circuit in this thread. The only benefit i see is that it operates at the resonant frequency without tuning, but it seems to have a potential startup problem.Is there any benefit to using dual stages vs full h bridge control with an adjustable induction heater.However as your melt gets hot the inductance changes so the resonance frequency changes and you get power loss... So this method may be better then phase control for that reason.I guess that you would need to add a pll tracking circuit to the mcu and have the mcu periodically sample the pll output to adjust the center frequency..

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 19, 2018, 07:02:38 pm
content: Back in industry, I used a single stage, full wave, frequency offset control. Simplest power stage, but crappy to compensate. Wanted to try phase control, but the driver and output stage didn't have the logic to support it. Yes, you need a PLL to track resonance, or something near it in any case. Phase shift PWM gives you effectively a variable voltage source, exactly what you need. With the system at resonance, the amplitude response is a (single or repeated?) pole at the tank time constant, low Q and easy to compensate.Downside is 100% switching loss and EMI. A tri-level inverter (a half bridge with a shorting-to-zero mode) might be preferable for this reason.Tim

author: j2000
author_rank: Newbie
timestamp: August 05, 2018, 05:06:12 am
content: Hey Strawberry...thanks for the schematic...Did u sell DIY kit complete?RegardsJoel

author: IvanLazarov
author_rank: Newbie
timestamp: August 09, 2018, 02:46:49 pm
content: Hi Strawberry, thanks for sharing the schematics for your induction heater. I will try to build it myself.Can you please advice what should be the current rating of chokes L1 and L2? If the total power is 2KW, does that mean that each choke should be rated at minimum of 20A?What is the purpose of the additional circuit on the right hand side that you included in the latest revision the drawing?Cheers,Ivan

author: strawberry
author_rank: Super Contributor
timestamp: August 09, 2018, 10:00:13 pm
content: 1/If you want do serious staff with it, then L1 L2 will be redesigned.2/It is protection circuit idea

author: RolingStones
author_rank: Newbie
timestamp: October 03, 2018, 08:45:07 am
content: Looks impressive and well buildMay I ask if you if you have tried using litz wire for heating coil instead of the copper tube? I have been working with a smaller 1000W ZVS drive and trying to optimize the electrical hysteresis by heating an iron pipe (high ferromagnetic material). Using a copper tube as heating coil the iron (Fe) heats faster than when using a litz wire. Theoretically it should be the other way around.

author: RolingStones
author_rank: Newbie
timestamp: October 08, 2018, 06:52:38 am
content: Quote from: strawberry on September 27, 2017, 07:18:51 pmWere you able to design the 3kW? I would be very interested in seeing it in action.

author: SharkyJr
author_rank: Newbie
timestamp: October 13, 2018, 02:44:39 pm
content: Hey thanks for sharing this! Im a beginner in Electronics and i wanted to know what should be the power rating of the resistors? I noticed in the order history, you shared on Drive, that the 1k and the 10K are 1/4W but no info on the other ones.

author: aamirchef135
author_rank: Newbie
timestamp: November 26, 2018, 08:01:28 pm
content: Where I can buy it and how much pleaseSent from my SM-G935F using Tapatalk

author: DR Martin
author_rank: Newbie
timestamp: December 07, 2019, 12:53:21 pm
content: Do you have the Altium source files for you rev. 2 board with protection?

author: krul_serwisu
author_rank: Newbie
timestamp: April 23, 2020, 08:30:32 am
content: Hello,Could you tell what is the gauge of the wire you've used to make the inductors? As I've seen there are 32w of 4-wire wick.