IGBT Dimmers

[Guy Macon]

I need to learn a bit more about IGBT dimmers in the 10-100kW range.
I have done a lot of work with IGBTs generating AC from a DC buss,
and a bit of work with SCR/Triac dimmers, but have never used IGBTs
in dimmer circuits. Does anyone here have experience with them?

My initial impression is that I will be able to reduce harmonics
and that the price will be quite a bit higher, but what about
power dissipation and product weight (smaller chokes)?

Wild idea: could this possibly be an application suitable for
a GTO (Gate turn-off Thyristor)?

-----------------------------------------------------------

Results of my preliminary web search:

The Silence of the Lamps: The New Wave in Dimming
http://livedesignonline.com/mag/lighting_silence_lamps_new/

Back to the Future: Sine wave dimming
http://livedesignonline.com/mag/lighting_back_future/

Cost of Energy Comparison, IGBT vs SCR Dimming Equipment
http://www.lolcontrols.com/clientuploads/techdocs/87-0614.pdf

Benefits of IGBT vs. Sinewave Dimming
http://www.etdimming.com/clientuploads/downloads/87-0539.pdf

Benefits of IGBT vs. SCR Dimming
http://www.etdimming.com/clientuploads/downloads/87-0540.pdf

IGBT vs. SCR Dimming Spreadsheet
http://www.etdimming.com/clientuploads/downloads/compare_energy.xls

Using IPS Dimmers to Reduce Power Line Harmonic Currents
http://www.etdimming.com/clientuploads/downloads/LowHarm_npn.pdf

Effects of harmonics on power systems
http://ecmweb.com/mag/electric_effects_harmonics_power_2/
http://ecmweb.com/mag/electric_effects_harmonics_power/

United States National Committee Powerline Harmonics Position Paper
http://grouper.ieee.org/groups/harmonic/docs/usccemc9901.pdf

Wikipedia: Dimmer
http://en.wikipedia.org/wiki/Dimmer

Wikipedia: Gate turn-off Thyristor
http://en.wikipedia.org/wiki/Gate_turn-off_thyristor

Powerpedia: Thyristor
http://peswiki.com/index.php/PowerPedia:Thyristor

 

[Phil Allison]

"Guy Macon"

I need to learn a bit more about IGBT dimmers in the 10-100kW range.

** Incandescent lamps in the " 10-100kW range " are rare beasts indeed.

You sure about wanting single channel dimming at such huge power levels ?

I have done a lot of work with IGBTs generating AC from a DC buss,
and a bit of work with SCR/Triac dimmers, but have never used IGBTs
in dimmer circuits. Does anyone here have experience with them?

** IGBTS are used in two quite separate ways as dimmers - as you first URL
alludes to.

1. Phase control by chopping the AC wave.

2. PWM of the AC wave to produce sine wave output at lower voltages.

My initial impression is that I will be able to reduce harmonics
and that the price will be quite a bit higher, but what about
power dissipation and product weight (smaller chokes)?

** The issue with phase control is that the fast switching of large currents
generates EMI - particularly bad in the audio and AM broadcast bands.
Choke filtering helps with the AM band noise - but annoying buzz injection
into audio systems is still there.

With IGBTs, the turn on and off times can be controlled to reduce ( AM band)
EMI, plus the chopping of the AC wave normally operates in the reverse
sense - ie starting at zero volts, rising slowly with the AC input voltage
and cutting off as required.

With PWM sine wave dimming, EMI can be virtually eliminated making these
dimmers very suitable for use in close proximity to sensitive audio gear.
Sine wave dimmers cause no harmonic current in the neutral and have unity
power factor - but cost a lot more to make than the simple phase control
types.

Phase control dimmers, of whatever type, DO cause harmonic currents and have
poor power factors - despite the false claims being made in some of the
URLs you posted.

But they *are* cheap.


........ Phil

 

[[email protected]]

I need to learn a bit more about IGBT dimmers in the 10-100kW range.

Who would need a dimmer for a lighthouse? Isn't that self-defeating?

 

[John B]

I need to learn a bit more about IGBT dimmers in the 10-100kW range.

Here's one that you missed, which might be of interest:

http://semitone.sourceforge.net/wiki/index.php/Semitone_Diamond

It has several ouput modules including IGBT.

 

[Guy Macon]

Who would need a dimmer for a lighthouse? Isn't that self-defeating?

Just because you haven't prsonally worked with Incandescent fixtures
that draw more than 10kW of power, tha doesn't mean that they don't
exist. For example:

20kW Fresnel light
http://www.panavision.com/product_detail.php?maincat=3&cat=53&id=213

145kW Super Wendy light (224 bulbs x 650W = 145.6kW)
http://www.panavision.com/product_detail.php?maincat=3&cat=60&id=278

In addition, common usage of the the term "dimmer" referes to a
device that reduces the wattage of AC power, and does not specify
the load (although if the load isn't resistive, that should be
mentioned). A nickel-chromium resistance wire heating element
can also be dimmed. In such a case the load is still incandescent,
with the output mostly infrared and with with a small amount of
the output in the visible red.

 

[[email protected]]

http://dictionary.reference.com/browse/joke

 

[Guy Macon]

Here's one that you missed, which might be of interest:

http://semitone.sourceforge.net/wiki/index.php/Semitone_Diamond

It has several ouput modules including IGBT.

Thanks! I found a lot mor by doing a Google search on "Open Dimmer":
http://www.google.com/search?q="open+dimmer"

 

[Phil Allison]

"Guy Macon" :

145kW Super Wendy light (224 bulbs x 650W = 145.6kW)
http://www.panavision.com/product_detail.php?maincat=3&cat=60&id=278

** That is not a single load to a dimmer.

Would require at least three huge dimmers, one for each phase.

In addition, common usage of the the term "dimmer" referes to a
device that reduces the wattage of AC power, and does not specify
the load ..

*** Shame how all your URLs were about dimming lamps.



......... Phil