Author Topic: 10kW 240Vac-line-powered ZVS induction heater?  (Read 609 times)

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1298
  • Karma: +62/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
10kW 240Vac-line-powered ZVS induction heater?
« on: July 06, 2021, 05:44:50 AM »
Still in the planning/simulation stage, but time to seek input/suggestions.  This is an induction heating driver powered directly from rectified 240Vac line.  No bulk capacitance, so induction power will track line voltage.  Output will be ferrite-transformer coupled to work coil, for both isolation and to reduce voltage.

    Up to 10kW (for use on a 40A 240V circuit).
    ~100kHz frequency (perhaps 80kHz minimum, ~200kHz maximum)
    Resonant capacitors on primary side.  (Transformer handles resonant current.)
    IXYH24N170CV1 24A 1700V TO247 IGBTs, 4 total, 2 parallel pairs.
    SCT2H12NY 4A 1700V SiC FET for gate drive to IGBTs
    GD10MPS17H 10A 1700V SiC diodes across IGBTs (which have no internal diodes)
        (ZVS circuit ideally has no reverse IGBT voltage, but slow turn-off requires diodes for momentary conduction.)

My thought for the LARGE output transformer:
    4:1 ratio (with the idea to match voltage from 60V direct-drive ZVS systems).  Would love to learn more about inductance and frequency of typical work coils for <= 10kW power.
    Two sets of large U93/76/30 U-cores arranged to look like an even larger E-core set.
    4-turn primary made of 90mm x 0.2mm copper foil wound as four layers around E-core center.  Leads (copper pipe or bus-bar) exit one end of the E-core set.
    1-turn secondary, 90mm x 0.5mm copper, over (around) primary.
    Windings spaced radially to allow for axial forced-air cooling.
    Each work coil can be soldered to its own 1-turn primary if desired.  Core is separable, so new secondaries can be slid into place.
    90mm x 0.5mm secondary winding can be extended as parallel-plate leads in order to locate work coil farther from transformer without adding significant additional parasitic inductance.

For circuitry, here's my modifications to the simple ZVS oscillator in order to accommodate larger forward drop of HV devices while keeping Vge low voltage close to 0V:


Any feedback and suggestions would be appreciated.  Likely to be some time before this project gets to the top of my list.

Also thinking of a variation w/o ferrite transformer for driving my SSTC.
David Knierim

Offline Twospoons

  • High Voltage Technician
  • ***
  • Posts: 111
  • Karma: +2/-0
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #1 on: July 06, 2021, 12:05:41 PM »
I would have thought fat litz > foil for the transformer.  Looking at the transformer in the Panasonic microwave oven inverter on my desk they've used multifilar (not true litz wire) wire on both primary and secondary.  The primary looks to be at least 50 strands of 0.2mm enameled wire. This is only a 1kW inverter.

If you have a gap in your core you might find some odd current distributions turning up in the foil.  Easy to run a sim with FEMM as a sanity check.

I'm interested to see what you come up with as I'm toying with the idea of a more modest 2kW induction heater, also offline.  But I really need to finish a lot of other projects first  :-[
« Last Edit: July 06, 2021, 12:07:25 PM by Twospoons »

Offline Mads Barnkob

  • Administrator
  • High Voltage Expert
  • *****
  • Posts: 1823
  • Karma: +47/-0
  • Denmark
    • View Profile
    • Kaizer Power Electronics
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #2 on: July 06, 2021, 10:39:03 PM »
Since you want to run this as a cheap induction hob, you could maybe find some more inspiration in how its made?

Induction hobs in Europe are built to 2300W, as 230VAC at 10A is the most common fused group in houses.

My analysis of how it achieves that power rating straight from mains without bulk capacitance is here about quasi-resonant inverter https://kaizerpowerelectronics.dk/general-electronics/hacking-ikea-2kw-induction-hob/
https://kaizerpowerelectronics.dk - Tesla coils, high voltage, pulse power, audio and general electronics
https://www.youtube.com/KaizerPowerElectronicsDk60/join - Please consider supporting the forum, websites and youtube channel!

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1298
  • Karma: +62/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #3 on: July 07, 2021, 05:47:12 AM »
Quote
My analysis of how it achieves that power rating straight from mains without bulk capacitance is here about quasi-resonant inverter https://kaizerpowerelectronics.dk/general-electronics/hacking-ikea-2kw-induction-hob/
Yes, that is roughly the circuit I used for my 23kHz eddy-current levitation box.  It was tricky getting it to work with high-Q loads.  If I were to build that box again, would likely try a two-transistor ZVS oscillator.  Induction cooktops hare relatively low-Q loads, with sensors that turn the unit off when no pan is present (ie. when Q is high).

Quote
I would have thought fat litz > foil for the transformer.  Looking at the transformer in the Panasonic microwave oven inverter on my desk they've used multifilar (not true litz wire) wire on both primary and secondary.  The primary looks to be at least 50 strands of 0.2mm enameled wire. This is only a 1kW inverter.

Yes, litz (multifilar) would be my normal thought.  However, I think it is difficult to get equal voltage on each strand when the turn-count is extremely low (ie. 1 or 2 in this case).  I gather it can be more efficient in such cases to use copper sheet and force the field to (mostly) avoid penetrating the windings.  Saw a tear-down video somewhere of a large TIG welder.  It's transformer was constructed similarly to my thought here, wound with copper sheet.

Quote
If you have a gap in your core you might find some odd current distributions turning up in the foil.  Easy to run a sim with FEMM as a sanity check.
No gap planned.  I don't have experience with any finite-element software (except for viewing results others generated).  Is there a free or cheap application that is reasonably easy to learn?

BTW, unrelated, but I just had to repost this edit, as well as my initial reply this evening.
« Last Edit: July 07, 2021, 06:59:26 AM by davekni »
David Knierim

Offline Twospoons

  • High Voltage Technician
  • ***
  • Posts: 111
  • Karma: +2/-0
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #4 on: July 07, 2021, 10:07:27 PM »

  I don't have experience with any finite-element software (except for viewing results others generated).  Is there a free or cheap application that is reasonably easy to learn?
https://www.femm.info/wiki/HomePage
Free 2D and 2.5D finite element simulator for magnetics, electrostatics, current  flow and heat flow.  Surprisingly useful, as many problems can be reduced to a 2d slice and still yield good results.
I think the hardest thing to get to grips with is setting up the boundaries around the problem - I usually use periodic boundaries to simulate the rest of the universe. There's a pretty good manual, included with the software, that describes all this.
« Last Edit: July 08, 2021, 04:42:59 AM by Twospoons »

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1298
  • Karma: +62/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #5 on: July 08, 2021, 03:42:00 AM »
Quote
https://www.femm.info/wiki/HomePage
Free 2D and 2.5D finite element simulator for magnetics, electrostatics, current  flow and heat flow.  Surprisingly useful, as many problems can be reduced to a 2d slice and still yield good results.
I think the hardest thing to get to grips with is setting up the boundaries around the problem - I usually use periodic boundaries to simulate the rest of the universe. There's a pretty good manual, included with the software, that describes all this.
Thank you!  This looks interesting and useful.  Do you happen to know if it can handle radial symmetry?  In other words, could I simulate a vertical plane slice through a Tesla coil from center out to "infinity", handling the equations correctly for the wedge-shaped slice?  Or is that what 2.5D means?
« Last Edit: July 08, 2021, 03:46:23 AM by davekni »
David Knierim

Offline Twospoons

  • High Voltage Technician
  • ***
  • Posts: 111
  • Karma: +2/-0
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #6 on: July 08, 2021, 04:41:26 AM »
Yes thats what 2.5D means. Also know as "axisymmetric ".  Good for any "solenoidal" type of problem.

Offline davekni

  • High Voltage Expert
  • ******
  • Posts: 1298
  • Karma: +62/-0
  • Physicist, engineer (electronic), and hobbiest
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #7 on: August 29, 2021, 06:26:24 AM »
Quote
https://www.femm.info/wiki/HomePage
Free 2D and 2.5D finite element simulator for magnetics, electrostatics, current  flow and heat flow.  Surprisingly useful, as many problems can be reduced to a 2d slice and still yield good results.
I think the hardest thing to get to grips with is setting up the boundaries around the problem - I usually use periodic boundaries to simulate the rest of the universe. There's a pretty good manual, included with the software, that describes all this.
Finally got to learning FEMM.  Very glad I did.  Thank you again for the pointer!  GUI is not typical Windows style, so takes some learning.  Worth the trouble.  (LTSpice also has an atypical GUI and is well worth learning.  Unfortunately, not the same atypical GUI as FEMM.)  So far I've simulated both versions of this transformer and some QCW coil geometry ideas to optimize coupling.

Quote
I would have thought fat litz > foil for the transformer.
For a 1-turn secondary, I can get to roughly 1/5th power dissipation with 100,000 strands of 44AWG wire per FEMM.  However, a real 1-turn litz coil will not meet one of FEMMs assumptions, that each strand is uniformly distributed across the bundle.  With one fat turn, it is not practical to get each strand to be equally on the inside and outside of the turn.  I'm not sure how much uniformity is possible with a 1-turn coil.  In the extreme of no uniformity (strands layered from inside out), power dissipation will be higher than for copper foil, around 2x for 25% fill factor.  (That is for foil thickness of 2x skin-depth or more.)
David Knierim

Offline Twospoons

  • High Voltage Technician
  • ***
  • Posts: 111
  • Karma: +2/-0
    • View Profile
Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #8 on: August 29, 2021, 01:04:19 PM »
I'm glad you found FEMM to be useful. Numerical simulation (done with the appropriate caveats in mind) is great for getting answers where analytical solutions are prohibitively difficult. Analysing magnetic systems is definitely one of those situations.  I've been fortunate enough to have access in the past to Ansys Maxwell, a full 3D electromagnetic FEA software package. Very capable, very slow on complex problems (days to run some of my simulations), and of course very expensive (NZ$30k per CPU core!).  I was using it to simulate PCB coils for wireless charging, so the geometry was very complex, hence the long simulation times.

High Voltage Forum

Re: 10kW 240Vac-line-powered ZVS induction heater?
« Reply #8 on: August 29, 2021, 01:04:19 PM »

 


* Recent Topics and Posts

post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
Today at 04:30:28 AM
post Keep blowing capacitors
[Spark Gap Tesla Coils (SGTC)]
pmlapl
September 27, 2021, 11:21:43 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 27, 2021, 06:47:52 PM
post Isogrid Features
[General Chat]
Patrick
September 27, 2021, 11:19:47 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 27, 2021, 05:26:36 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
September 26, 2021, 07:51:40 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 26, 2021, 02:26:25 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 26, 2021, 10:32:14 AM
post Re: Tesla plate
[General Chat]
klugesmith
September 25, 2021, 11:09:30 PM
post Re: Measuring TC secondary parameters
[General Chat]
davekni
September 25, 2021, 09:51:49 PM
post Re: Tesla plate
[General Chat]
Duane B
September 25, 2021, 09:18:43 PM
post Re: Measuring TC secondary parameters
[General Chat]
Duane B
September 25, 2021, 09:16:36 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 25, 2021, 08:53:36 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 25, 2021, 06:49:45 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 25, 2021, 05:34:54 AM
post prodc9 interrupter plexi case
[Dual Resonant Solid State Tesla coils (DRSSTC)]
costas_p
September 24, 2021, 07:14:53 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 24, 2021, 05:37:56 PM
post Re: Tesla plate
[General Chat]
Benbmw
September 24, 2021, 05:20:01 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Netzpfuscher
September 24, 2021, 07:26:30 AM
post Tesla plate
[General Chat]
Duane B
September 24, 2021, 01:54:49 AM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2021, 09:08:23 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 23, 2021, 07:09:23 PM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2021, 05:46:38 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 23, 2021, 11:12:25 AM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Netzpfuscher
September 23, 2021, 08:49:51 AM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
davekni
September 23, 2021, 06:15:34 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
September 23, 2021, 05:48:40 AM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 22, 2021, 07:21:12 PM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 22, 2021, 10:41:20 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
September 22, 2021, 07:07:48 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 22, 2021, 05:26:40 AM
post Re: Measuring TC secondary parameters
[General Chat]
MRMILSTAR
September 22, 2021, 05:14:30 AM
post Measuring TC secondary parameters
[General Chat]
Duane B
September 22, 2021, 05:01:22 AM
post Re: Load resistance and discharge terminal for my 14-stage CW multiplier
[Voltage Multipliers]
MRMILSTAR
September 21, 2021, 10:33:34 PM
post Re: Futurist's DRSSTC 0.5
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Mads Barnkob
September 21, 2021, 07:21:50 PM
post Re: Load resistance and discharge terminal for my 14-stage CW multiplier
[Voltage Multipliers]
klugesmith
September 21, 2021, 05:24:35 PM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
futurist
September 21, 2021, 04:18:47 PM
post Load resistance and discharge terminal for my 14-stage CW multiplier
[Voltage Multipliers]
MRMILSTAR
September 21, 2021, 06:30:44 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
September 21, 2021, 06:04:52 AM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
fh89
September 21, 2021, 03:56:28 AM
post Re: Idea for QCW DRSSTC
[Dual Resonant Solid State Tesla coils (DRSSTC)]
johnnyzoo
September 20, 2021, 09:24:10 PM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Uspring
September 20, 2021, 05:07:43 PM
post Re: Large Rectifier Tube
[General Chat]
Benbmw
September 20, 2021, 04:12:27 PM
post Re: Proper phase lead adjustment at the input
[Dual Resonant Solid State Tesla coils (DRSSTC)]
Chrisader
September 20, 2021, 10:40:33 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 20, 2021, 10:39:59 AM
post Re: BrOdin coil - High power Big sparks!
[Dual Resonant Solid State Tesla coils (DRSSTC)]
futurist
September 20, 2021, 10:38:31 AM
post Re: Large Rectifier Tube
[General Chat]
klugesmith
September 20, 2021, 07:07:55 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 20, 2021, 06:03:57 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
davekni
September 20, 2021, 05:31:57 AM
post Re: Help with SSTC feedback circuits with 4046 IC and Schmitt Triggers
[Solid State Tesla Coils (SSTC)]
AFreshLad
September 20, 2021, 04:59:17 AM

Sitemap 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 
SimplePortal 2.3.6 © 2008-2014, SimplePortal