SMMA Fall Technical Conference - Wrap-Up

Well, I don't really have any new pictures, so here's some dessert.

Yesterday wrapped up my trip to the SMMA Fall Technical Conference and I failed to update the "live blog" (which I have decided never to do again) mostly because I spent many hours in the airport and on a plane. But anyway, I am back in Cambridge now. The trip was definitely a good one for me. I expected to learn a lot, and I did. Here's a few things that I came away with:

• The electric motor industry is very big, reaching out into many markets. The biggest ones seems to be industrial (big constant duty induction motors) and automotive (little accessory PM motors, not traction). But both of those markets took a big hit. The "new markets" are renewable generation (wind) and automotive traction. Almost everyone identified these markets, but few have stepped into them yet, it seems.

• There was a very interesting idea proposed by EMERF for a pre-competitive research consortium that could maybe focus on some of these new markets, or on PM issues. The thing that comes to mind for me is the FEMMulator. Here's what I mean: The "industry" is slow, and built on a large pool of experience and expertise and data from existing designs. And then there's the FEMMulator...a free program that one person wrote to run an iterative FEA design simulation on a brushless motor. Here's the "disruptive technology," except instead of a technology it's really more of a disruptive methodology. The idea that anyone can get access to enough information and computing power to design a motor these days means that the process is different...and a collaborative research intiative seems to make sense, IMO.

• On the technical side, there are a lot of things I know now that I will have to look at more closely. For one, segmented drive PWM. I thought I knew all there was to know about PWM in an h-bridge or inverter, but apparently not. So I will look into the more interesting methods and see if they could be applied to my controller at all. Also, there is a commercial sensorless zero-speed-start BLDC controller available call the DPFlex, from Agile Systems. It uses variations in inductance to measure starting position of the rotor. I knew this was possible and had been researched, but it's interesting to see one in production. I wonder if I could get my hands on one for cheap...or else it's good at least to know that it exists.

• There were also some ideas that were met with a bit of skepticism. There was QM Power, which, well I understand where the skepticism comes from. I actually thought their presentation was pretty good, but after going back and reading their website...their idea is either ridiculous or they do have a clever breakthrough and need to fire their entire marketing/promotional team for making it sound ridiculous. There's also a clever idea for a harmonic drive motor, which is like a harmonic drive gearbox but without the strain wave generator...you use electromagnetic forces to move the spline. That one is really clever, and it would certainly work. The question is how efficient it would be. But it would be great for robot actuators, etc.
  

• I got some good feedback on the axial motor concept. It's fairly unique even among axial motors, and most people think it could get very good power/torque density. Interesting to see how it works out.

That's pretty much the wrap-up. Lots of new contacts and lots to think about. It was an good trip for me and I think the presentation part went pretty well. (Nobody asked about the segway...so that's good...) As promised, a link to the presentation I did (minus videos) and also to the paper. (Overview of the Summer Engineering Workshop with emphasis on the BWD Scooter project, with cool pictures of course.)

SMMA Fall Technical Conference - Day 1

Today was the pre-conference workshops day, and that meant a four-hour course on "Fundamentals of Brushless Motor Control" for me.

Oh boy.

Despite the 8AM-ness of it, I got a lot out of it. It was just the right level for me...stuff I had seen before but don't full understand yet. Hence the reading material. That's the kind of thing that will keep me entertained for quite a while.

For one, I learned that there are more ways than I knew of to drive a PWM signal in an h-bridge or 3-phase bridge. I don't really understand some of the more clever ways yet, or the differences in performance, but it's something to look into in the controllers I build.

Other than that, today was Essex Active plant tour day. I learned what a slot wedge is:

A slot wedge.

It's a wedge that goes in slots. (Motor slots, of course.) It can be made of many things, including Nomex. The windings presumably go inside the wedge. And presumably the wedge is a tad longer than the slot. So the windings never touch steel. Genius. I wish I had some when we were winding the scooter motors. Oh well.

My table-top demo is ready and I will be manning the post early tomorrow morning. Then in the afternoon I present, right before AC Propulsion... Moderately frightening. More pictures tomorrow when that's all over with and I can relax a bit.

Live from Chicago: SMMA Fall 2009 Technical Conference

Here goes my first-ever attempt to use the blog in semi-real-time.

This week, I am in Chicago for the SMMA Fall 2009 Technical Conference.

The SMMA is "The Motor and Motion Assocation." (The 'S' is silent.) Actually it used to stand for the Small Motor Manufacturer's Association. I wonder if I can get it changed to the "Scooter Motor Manufacturer's Association." Probably not. But anyway, you can find more information on the SMMA, which serves as the trade association for the electric motor and motion control industries, here: http://www.smma.org.

I am participating in the conference thanks to support from the Electric Motor Education & Research Foundation (EMERF) which, as the name might suggest, is right up my alley. This foundation supports and promotes academic, pre-commercial electric motor R&D, as well as educational initiatives in the field of electric motors. More information is available here: http://www.emerf.org.

This all has to do with the BWD Scooter project. Since we had the completely original, not ripped-off at all idea of making brushless hub motors for a kick scooter, I made a contact at Proto Laminations who is also a member of the SMMA/EMERF. Having now actually made brushless hub motors for a scooter, I am going to present it, or, I guess, present the Summer Engineering Workshop and its fleet (yes, fleet now) of vehicles. Of course, the scooter is the only one that's in any way portable:

I did say "in any way."

And since it is generally not acceptable to ship/check/carry batteries that you made yourself, the A123 pack has to stay at home. But cordless drills (and their batteries) are totally fine:

All Tech men carry batteries...and cordless drills.

Ok TSA? So back off. Or don't:

Not surprising.

Actually, the trip out went smoothly. Actually, very smoothly. Actually, it was the single most coordinated thing I have ever seen at an airport. A full 50 minutes before the scheduled departure time, we were told to board the aircraft as quickly as possible because they were going to try to beat a storm. ~40 people got on and sat down, the jets spooled up, and we did a rolling takeoff 20 minutes early. Amazing. I honestly don't see what all the complaining is about air travel...

As for the scooter, it survived. Or wait, did it!? Why does the rear motor feel like it's got Jello in it? This is usually a sign of a phase-to-phase short, which, if you've ever shorted the leads on a PM motor, you know is electronic braking. Well, this was a scary few minutes of wondering if the phase windings somehow shorted during transport. But the problem was a lot simpler apparently:

?

Well, actually, I have no idea what the problem was. But I know what the solution was:

1. Remove strain relief zip-tie.
2. Replace strain relief zip-tie.

Problem solved. I don't really want to know what is going on. At least it's not inside the motor. I just have to not mess with it for the next three days. Did I mention that I hate live demos? This is why I obsessively video tape everything while it's working. And why I brought a soldering iron...just in case. Also, the non-functional switch broke:

:(

But since it was non-functional, I guess it's okay.

Anyway, tomorrow I am taking an early-morning brushless motor control course where I might learn just how wrongly I've been doing it. So sleep may be in order. My presentation is on Wednesday, and I will post the slides right after. (But by now, you probably know what to expect.) And, of course, I will get to see all the other demos and presentations. Pictures and updates to come.