Looking for "matrix converter" experiences

[jraef]

In a project I am working on, the end user has requested that we integrate Yaskawa AC7 "matrix converters" as a regenerative AC drive, as opposed to PWM based regenerative VFD offerrings. I have plenty of experience with Yaskawa products and have no lack of confidence in them, but I have never come across their relatively new (to me) AC7 matrix converters. I know it's been out for a few years now, but I've never seen a request for one nor have I seen one in action.

I'm pretty comfortable with what it is from reading the sales literature and some white papers, what I am looking for is anyone who has had hands-on experience with them and can relate some of the good, and bad, things I can look forward to experiencing, the stuff that doesn't make it into the sales lit.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
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[dArsonval]

Converting a matrix?

Couple that term with Pulse Width Modulation, Regenerative,
Variable Frequency Drive, Muffler Bearings, Ka-Neuton Values,
Mo-Ba-Tron Units, and a box of Grid Squares held up by a Sky Hook.
One wonders... What happen to the "switch"?
The thing you flipped up... to turn all this [stuff] ON.

It's still around isn't it?

John

 

[benta]

John, your sarcasm is misplaced.

A matrix converter drive is characterised by having bidirectional power switches and no DC-bus, meaning no bulky storage capacitor and also no need for power factor correction.
It is also symmetrical, meaning regeneration is inherently built-in.

More info here:

http://www.die.ing.unibo.it/dottorato_it/Matteini/Matteini_PhD_part2.pdf

jraef, I've no practical experience, but the theory looks solid.

Chers,

Benta.

 

[jraef]

I agree, it LOOKS good, but so did several of my jobs when I signed on... I have since learned to be more skeptical and ask people with direct experiences. There seems to be a dearth of people in this forum who have had anything to do with them. Now I wonder if it's a lack of exposure, a fear of the unknown, or some really big pitfall I am unaware of.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[benta]

"Now I wonder if it's a lack of exposure, a fear of the unknown, or some really big pitfall I am unaware of."

Yes to the first two points.
I haven't heard of any pitfalls.
I am more inclined to subscibe it to a lack of suitable power semiconductors and mature control algorithms.

That Yaskawa brings out a commercial product is encouraging.

Benta.

 

[ozmosis]

Jeff
I don't know about the Yaskawa unit but the company we both worked for a while ago developed one and had two issues, maybe three:
1)Ability to cope well on brown/blackouts was a challenge. There are no DC link caps and this created a few issues.
2) Operating on very high impedance supplies created harmonic resonance around the high switching frequency
3) EMC filtering was always a challenge.
The project was dumped before it got to the market but the technology was always interesting.

 

[jraef]

Thanks Patrick.
Apparently this is becoming a big deal in escalator applications, especially reversing ones, because they able to regenerate when people are going down. That was the only real world application Yaskawa could offer and none of them were local. The end user was uncomfortable with being a local guinea pig for them.

My customer was planning on using them on a pallet lift in an automated storage and retrieval system. The regen capability was very attractive to them because in their application, most of the time the lift was going up empty and coming down full (they had one large hydraulic lift for loading pallets into the racks from the truck dock). But we ended up using another brand that offered slightly more conventional and proven technology (you might guess which one Patrick). We commissioned it last week, so far so good.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376