Motor Controller Design: A Photo Journal!

AC, DC, amps, volts and kilowatt. It's all discussed in here
zeva
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Post by zeva » Wed, 26 Nov 2008, 10:35

Hi all,

I've just finished putting together a web photo gallery plus commentary detailing my progress with DC motor controller design over the last few months. Check it out here:

http://www.zeva.com.au/tech/controller_design/

In short, I currently have a 600A controller of my own design installed and working in my MX5, right now! Yes, the same vehicle in which a Curtis 1231C blew up a few months ago and no, my controller doesn't whine.. Image

I've very much been of two minds putting all these pics up on the web, because they represent a lot of R&D effort, and I've vague intentions to market the thing if/when I'm happy with the design. But the socialist in me won over in the end (I'm a big fan of "open source") so I thought I should share it all with the community. Plus, it is a pretty tough build - I doubt many people would be game to tackle it and I can now speak from experience in saying that building a one-off is really not worth your time.. Unless you have lots of it, and/or like doing things just for the challenge, in which case go for it!
Ian Hooper
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Post by Johny » Wed, 26 Nov 2008, 15:14

Thanks Ian. I'm pretty that the support you get with this community will massively swamp any loss of income that providing these details could incur. (Any larger group would just buy one and reverse engineer it anyway). The other bonus is that you may get helpful comment on the design to save time/money down the track a bit.

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Post by Electrocycle » Wed, 26 Nov 2008, 16:06

awesome stuff :)

What to the FETs and diodes cost?
I've been planning on making my own much smaller controller, but have only been developing it with low voltage FETs so could be interested in adding some to your next order if possible :)
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Post by drowe67 » Wed, 26 Nov 2008, 20:30

Hi Ian,

Congratulations on your controller - an amazing effort.

I think it's also great that you are sharing your experiences - I am also a big fan of open source. I have been doing a lot of work in open hardware over the past few years, and working together with a community of developers and companies we have released real world, commercial, open hardware products in the VOIP IP-PBX space. It's also how I derive my day-day income - so open hardware really can be used to develop commercial products.

In fact it's been my experience that open hardware is a superior way of developing hardware products, just like open software is generally superior to closed. Lots more information on my blog, web site, various magazine articles etc, I won't rave on any more here....

Anyway a couple of ideas for your design:

1/ I would get in and make some measurements to sus out where those heating losses are coming from. Might be something easy fixed. Measure the currents and voltages through a FET and diode and see if the power dissipated matches your calculations. Maybe just test with a single section for a start.

2/ Not sure what sort of CRO you used to look at the waveforms (laptop based?). Would suggest taking a look at those gate waveforms using a Tek CRO or similar with a good analog BW (at least 100MHz, 500MHz preff). Given the physical size you have some pretty long runs there and it it quite possible you have some high frequency transients you may not be seeing. Simple inductance of the gate drive wiring loom may be slowing down the switching time. Use good probes with 1 inch ground connections, probe right at the FET, and compare waveforms along various FETs. Apologies if you already know all this.

3/ I was wondering about the failure modes of MOSFETs? Do they just turn into one lump with low R between the terminals? In that case you might get the 200V bus connected to the gate drive and hence pop everything. Would it be worth adding some protection? For example a small resistor (like an 0805 surface mount) or fuse in each gate drive design to sacrifice itself, and back-back zeners somewhere on each gate to quickly short any big voltages to ground. Maybe sense wires to detect a popped MOSFET and shut down the controller quickly.

Cheers,

David
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Post by AMPrentice » Wed, 26 Nov 2008, 23:12

Ian we hope you profit eventually from your controller.
I think once the heat issue is solved you should maybe
consider them partly built somewhere overseas then assembled here.
Otherwise some government funds should go your way like Toyota
has received and have a fab in WA to make them.
We need DC controllers or AC controllers made locally more and more
as the Aussie dollars plummets and hopefully stays there for exporters.
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Post by htial » Wed, 26 Nov 2008, 23:51

Aww...   ...The polycarbonate buss bars look so much better than the copper ones...

/noob statement...   Image

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Post by woody » Thu, 27 Nov 2008, 00:05

It's transparent aluminium, not polycarbonate. Don't you watch Star Trek?

It's a step up from Kearon's "Wireless Power" cover story for his unfinished Capri at the field day.

Hoops:

I'm guessing that a 2000A controller is just a longer version of the 1200 amp with fatter bus bars?

Would there be an advantage in having the motor outputs at the opposite end to the battery inputs ?

Maybe I eat too much chocolate, but your controller would look tastier in a triangular prism enclosure, like a Toblerone. Or have it all chocolate brown (anodised aluminium heatsinks) for the full effect.

cheers,
Woody
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Post by htial » Thu, 27 Nov 2008, 00:15

woody wrote: It's transparent aluminium, not polycarbonate. Don't you watch Star Trek?

It's a step up from Kearon's "Wireless Power" cover story for his unfinished Capri at the field day.

Oh yeah...   ...I forgot about that...

Where can I check out Kearon's cover story???...   ...I've watched his vids a number of times over now...

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Post by Johny » Thu, 27 Nov 2008, 00:16

Ian. I didn't see any mention of snubbers or something to absorb high frequency spikes from the DC bus so the electros don't suffer too much.

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Post by zeva » Thu, 27 Nov 2008, 00:54

HI all,

Thanks for the kind words and suggestions. The guys on the EVTech have also offered me a wealth of advice on how I might improve efficiency (and long-term reliability), so I've got some further experimentation to do before another build! But we're getting there.. at least I haven't blown anything up for a while Image

woody: Within reason you can just add more devices in parallel for higher current, but things get harder of course - bigger bus bars needed, longer hence higher inductance tracks cause more ringing & spikes, larger currents involved, etc. I figure 144V 600A would be fine for 90% of conversions out there - kind of ironic though that my own EV is in the other 10%!
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Post by ourbobby » Thu, 27 Nov 2008, 04:59

Hi Guys,
        I have an interesting EV Inverter Design article DIY. I can't see where I can upload files on this forum. Or is this not possible?

Also, are any of you familiar with the Rotoverter? Small input Large output. Can use Speed controllers - PWM. Just google rotoverter!!

Regards
Rob

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Post by Richo » Thu, 27 Nov 2008, 05:09

Click post options and select reply.
Then you will have options to upload.

Otherwise go to your "File manager" under "Member control Panel" at the top of the page.
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Post by evric » Thu, 27 Nov 2008, 05:31

Great work Ian.
144V 600A sounds good for me.
Eric.
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Post by ourbobby » Thu, 27 Nov 2008, 05:47

Richo wrote: Click post options and select reply.
Then you will have options to upload.

Otherwise go to your "File manager" under "Member control Panel" at the top of the page.


Sorry buddy, I'm a being a bit thick tonight. Can't see the upload option or file manager. Most forums actually have a specific file upload option spelt out when posting.

Regards
Rob

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Post by woody » Thu, 27 Nov 2008, 05:58

At the top of the page under the logo there are two lines:
^Forum Home -> ...
Member Control Panel

Also right in the top right corner is a Reply link <it's just over here ---------->

It takes you to the "Full Reply Editor".

Also below in the "Quick Reply" is a button (arrow in 2 squares) which takes you to the "Full Reply Editor".

cheers,
Woody (who just figured out half this stuff)
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Post by woody » Thu, 27 Nov 2008, 06:12

ourbobby wrote: Also, are any of you familiar with the Rotoverter? Small input Large output. Can use Speed controllers - PWM. Just google rotoverter!!
Hi Rob,

I had a quick look just now at the Rotoverter PDF from Panacea.

I'm not an Elec Engineer, but I work with lots of them.

Overlooking the "Over unity" and related buzzwords...

Quite a few of the techniques are done by good Variable Frequency Drives:
* Low voltage + hence low power when low torque required (compared to Direct-On-Line)
* Capacitors to recycle the Reactive current

Idling is by definition a 0% efficiency operation - no torque = no power output.

Others make sense:
* Changing out the squirrel cage rotor for a permanent magnet PMAC.
* Running in star or reducing voltage some other way so that magnetic saturation is not reached. I read in one of the two textbooks I've borrowed on Electric Machines that typically motors are designed to be magnetised about 10% over the most efficient point, and there are some magnetic losses (way less than 10%) due to this.

Others I'm not sure about:
* Capacitor tuning

There's a lot of over-unity and perpetual motion stuff (hooking motors to generators and getting more out of the generator than you put into the motor) which I just don't buy...

cheers,
Woody
Planned EV: '63 Cortina using AC and LiFePO4 Battery Pack

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Post by woody » Thu, 27 Nov 2008, 06:16

htial wrote:
woody wrote: It's a step up from Kearon's "Wireless Power" cover story for his unfinished Capri at the field day.
Where can I check out Kearon's cover story???...   ...I've watched his vids a number of times over now...
It wasn't the cover of a magazine, it was his (sleep-deprived) joke to people looking under the bonnet of his capri - at that stage he'd just bolted everything in, but not wired it up. He may have told it to his video, it might make it into episode 8.
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Post by Electrocycle » Thu, 27 Nov 2008, 06:28

When I read the words "over unity" I tend to close the browser :)
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Post by htial » Thu, 27 Nov 2008, 06:31

woody wrote:
htial wrote:
woody wrote: It's a step up from Kearon's "Wireless Power" cover story for his unfinished Capri at the field day.
Where can I check out Kearon's cover story???...   ...I've watched his vids a number of times over now...
It wasn't the cover of a magazine, it was his (sleep-deprived) joke to people looking under the bonnet of his capri - at that stage he'd just bolted everything in, but not wired it up. He may have told it to his video, it might make it into episode 8.


Ahh...   ...I follow now...

I know he did say something about a display in his Capri being wireless...   ...That might have been what I was thinking about...

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Post by ourbobby » Thu, 27 Nov 2008, 06:39

woody wrote:
Others I'm not sure about:
* Capacitor tuning

There's a lot of over-unity and perpetual motion stuff (hooking motors to generators and getting more out of the generator than you put into the motor) which I just don't buy...

cheers,
Woody


You seem to have a good grasp of basic procedures. Yes, its all in the capacitor tuning. My understanding is initial tuning is done with a bank of switched caps. Very difficult to find the resonance of a 3ph motor. Easier to suck it and see. Once you have the caps value for the res freq that's essentially the set-up. Using the PWM on the circuit/drive takes a little bit more thought. I do have a reply on my system somewhere from someone who persevered and got it going.

I'm working on something else at the moment, but, the RV does provide sequential torque for small input. With respect to EV's, that will translate to reduced battery use. Also, it is possible to concurrently run an alternator from the electric motor for very little energy. Thereby, increasing the trip length for EV travelling.

I'll look for the PWM article and post it when I find it. Not tonight though. By the way google Tesla Switch. It will blow your mind if you are not familiar with this. Leave you to discover that one for yourself.

Don't discount "overunity"! People have the Tesla Switch working!!

Off to bed now. Goodnight and regards to you all
Rob

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Post by ourbobby » Thu, 27 Nov 2008, 06:49

woody wrote: At the top of the page under the logo there are two lines:
^Forum Home -> ...
Member Control Panel

Also right in the top right corner is a Reply link <it's just over here ---------->

It takes you to the "Full Reply Editor".

Also below in the "Quick Reply" is a button (arrow in 2 squares) which takes you to the "Full Reply Editor".

cheers,
Woody (who just figured out half this stuff)


You and I must have different option enabled. I do not get a "Quick Reply" option with arrow in 2 squares. Maybe newbies cannot upload files.

Regards and definitely good night!
Rob

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Post by Andrew » Thu, 27 Nov 2008, 07:20

ourbobby wrote:
woody wrote: At the top of the page under the logo there are two lines:
^Forum Home -> ...
Member Control Panel

Also right in the top right corner is a Reply link <it's just over here ---------->

It takes you to the "Full Reply Editor".

Also below in the "Quick Reply" is a button (arrow in 2 squares) which takes you to the "Full Reply Editor".

cheers,
Woody (who just figured out half this stuff)


You and I must have different option enabled. I do not get a "Quick Reply" option with arrow in 2 squares. Maybe newbies cannot upload files.

Regards and definitely good night!
Rob


I've just made an update so that Noobie's can upload pictures. Once over 30 posts you can upload other types of files such as zip and PDF.

This is just a security measure. Image

Now back to the topic...
Last edited by Andrew on Wed, 26 Nov 2008, 20:21, edited 1 time in total.

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Post by ourbobby » Thu, 27 Nov 2008, 20:14

Andrew wrote:
ourbobby wrote:
woody wrote: At the top of the page under the logo there are two lines:
^Forum Home -> ...
Member Control Panel

Also right in the top right corner is a Reply link <it's just over here ---------->

It takes you to the "Full Reply Editor".

Also below in the "Quick Reply" is a button (arrow in 2 squares) which takes you to the "Full Reply Editor".

cheers,
Woody (who just figured out half this stuff)


You and I must have different option enabled. I do not get a "Quick Reply" option with arrow in 2 squares. Maybe newbies cannot upload files.

Regards and definitely good night!
Rob


I've just made an update so that Noobie's can upload pictures. Once over 30 posts you can upload other types of files such as zip and PDF.

This is just a security measure. Image

Now back to the topic...



Hi Woody , here is one of the posts from the EVgray forum - Yahoo group- lots on RV here:- As I don't like the restrictive practises here, it is unlikely that I shall post again. Why wait for5 50 posts to share information!!!

Best of luck with it

Both these updates here have been added to RV energy saving R and D
the comp.

Theory Comparison of bench drills efficiency

Two separate bench drills are obtained; drill no 1 is to be a single
PH (phase) 1 HP (horse power) rated motor; the other is to have an RV
modified motor. The RV modified motors can range from:

A 3PH 60CPS 3 to 7.5 HP230/460VAC motor, in this example apply the RV
motor in a 1 to 1.8 HP role. In a 50 hertz or 50 CPS RV motor, a 5 to
10 HP or a 4KW (5+HP) RV will afford approx 1-1.25 HP out put.

Tune the RV to match the other motors 1HP max load, then measure the
two readings by a cumulative Watt hour meter. After a day of drilling
by the same load, compare and evaluate the 2 readings Compare by the
classic A vs. B comparison.

Tips: Try to find any old belt driven machine you can, something that
looks easy to line up another motor and have clearance for an
oversized belt. Or get a custom Drill made up, it will be the most
efficient drill in the world.

On the RV modified drill motor, use low friction belts (test timing
belts for best RV performance ) what matters is that they have to
have the same RPM to be compared on performance , a 3600 RPM RV will
move tons at 360 RPM wood drill with an efficient low loss down
gearing.

It has since been advised that the lowest-loss you can do with belts
is to use rubber toothed timing belts. Regular V-belts have to have
too much tension just to get the belts to grip the pulleys and the
teeth in rubber toothed belts means you don't need so much belt
tension that way.

Timing belts are low friction:

http://www.dogpile.com/info.dogpl/searc ... 2Bfriction%
252Bpulleys/1/-/1/-/-/-/1/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-
/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/-/417/top/-/-/-/1

Timing belts from cars are also standard and are used in industrial
servomotor applications (less friction than V belts) also the grooved
V belts can run better. A Bench grinder 60 hertz 3PH 460VAC motor can
also be made to run more efficient in RV mode.

To be further made simple the speed and torque must match the ones
required for original operation or better, a pulley down stepped 3450
RPM RV will definitely outperform any stock 1725 1/4 to .5 HP motor.

A Basic example-1 HP RV is can be made from a 60 hertz 5 or 7.5 HP
3PH motor, the then max load is to be calculated and the RUN
capacitor can be set in a mid adjustment range (broad banded), even
though the Run cap wont be optimally tuned to the specific loaded
condition, the RV will outperform the normal motor!!!

Baldor's motor's can also wind up 120,240,380,460 & up to 920VAC 3PH
Motors which can be RV'ed anywhere from 100-120 200 240 VAC 47 -60cps
with only needing to be using capacitors and centrifugal start switch.

For an automatic tuning of the RV drill load, later we can switch to
an automatic computer controlled load sensor which can also utilize
the RV's hidden OU component and operation. This method is the
specific LOAD tuned Amplitude, frequency & pulse length. This is
where Hector details the RV's relation to OU and ZPE.

ANY motor can be run this way using adaptive electronics and reach
the FULL HP range of the rated motor in RV mode (preforming the HP
more efficiently) using Amplitude control Voltage from 120VAC to
460VAC (Frequency adjusting or boasting the voltage). Frequency
control from 0 CPS to Infinite

The engineering protocol involves a Pulse length control, when
adjusting from 0 to the MAX frequency length pulse, the operation is
determined by the sine wave or square DC wave length in time
(modified sine wave) & sine wave or any wave slope angle saw tooth,
incremental logarithmic, stepped pulsed, quadrature modulated or
phase modulated or any compound modulation or amplitude form, power
or RF current & voltage phased angles (power factor).

A frequency adjustable inverter Power supply has variable parameters
(amplitude control). When this concept is applied in RV mode the
Voltage regulates the impedance as if it were VARACTOR tuned LC. This
also regulates the HP output and energy saving Impedance states. The
frequency control regulates the speed, and thus horsepower output,
this is in combination with amplitude.

ANY frequency drive can be MODIFIED to do this; especially the 480ACV
rated ones by adding voltage and amplitude control. The frequency
drive needs to be constructed to regulate its final drive voltage
from 100 to 480VDC. This can be switched by the 3 PH transistor or
IGTBs 3x3 network. The drive can regulate motors into a full range of
parameters; this has been given open sourced in RV disclosure with
the advantage of having FULL rated horsepower at demand.

Any modified sine wave inverter can be modified to operate in
amplitude, frequency and pulse length control. The opto isolated
drives are the best, 12.7VDC operated electronics and also opto
isolated & computer driven are as an Extra option.

Any number of inverters can be arranged to create an improved
multiphase array, where also the computer can be used drivers by
using opto isolated stages.

One EFF example:

3 10KW inverters can drive 30KW 3 phase system with same source and
using computer driven 3PH trigger, pulse & amplitude generation. More
speed = more power which is gown geared to less speed. It is
recommended to test a 1/2 HP and 1 HP drill motor against a normal &
frequency regulated Over-rev'd RV Motor.

Range parameters are Hi frequency Hi HP in 450 CPS RV 3 HP motor will
give an equivalent output of a 30HP 50cps one.

In the RV drill tests the GEARS for the optimal performance at the
drill head against the normal drill, this gives the POWER to optimize
& is professional RV use in R&D to quantify and improve power
performance

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

Norm's big motor RV tests

Quote -Norman Wootan

I have a 30 HP Magnetek, Century E Plus Motor, 1760 RPM, 460 V. 35
A. running on 1.2 A @ 125 VAC input. I disassembled the motor and
washed the grease out of the bearings and machined off the large
aluminium cooling internal fan. Now the motor will free spool for a
long time when power is turned off. Very little rolling friction.

Congratulations, Norman Wootan on your MOUSTER RV setup the standard
book rules state you did the impossible. This will lead to rethink
the ways motors are engineered, but are up to the group and all
others to force this KNOWLEDGE into
The media and petrol mafia cartel faces. One megawatt motors running
with 10 amps! -Hector

Technical analysis-Hector


The 40KW motor is asynchronous operating by a squirrel caged motor as
per a description contained in standard engineering protocol. The
primary winding (stator) is connected to the power source and the
shorted secondary (rotor) carries the induced secondary current.

The Torque is produced by the action of the rotor (secondary)
currents on the rotary repulsion from the off phase 3 ph fields and
capacitor vectored virtual 3rd phase.

The induction motor is a common form of asynchronous motor and is
basically an AC transformer with a rotating secondary. The primary
winding (stator) is connected to the power source and the shorted
secondary (rotor) carries the induced secondary current.

NOTE: An Ac transformer with a rotating secondary.

A motor as a transformer does not need to use POWER unloaded. Power
engineering in the last hundred years totally misused power in 100%
waste modes, a motor can work as a transformer unloaded with minimal
power consumption.

Rotors typically consist of a laminated, cylindrical iron core with
slots for receiving the conductors. The most common type of rotor has
cast-aluminium conductors and short-circuiting end rings.
This "squirrel cage" rotates when the moving magnetic field induces a
current in the shorted conductors. The speed at which the magnetic
field rotates is the synchronous speed of the motor and is determined
by the number of poles in the stator and the frequency of the power
supply: ns = 120f/p, where ns = synchronous speed, f = frequency,
and p = the number of poles.

Synchronous speed is the absolute upper limit of motor speed. If the
rotor turns exactly as fast as the rotating magnetic field, then no
lines of force are cut by the rotor conductors, and torque is zero.*
ZERO (ZERO point energy) (Note here that on 0 torque we have 0 power
on a theoretical 0 current) being self induction NEGATIVE in relation
to rotary field the VOLTAGE vector becomes NEGATIVE resistance to
line power contributing power to such source (seen as POWER factor
correction on LOW impedance but as OU in matched hi impedance
circuits.)

When running, the rotor always rotates slower than the magnetic
field. The rotor speed is just slow enough to cause the proper amount
of rotor current to flow, so that the resulting torque is sufficient
to overcome windage and friction losses, and drive the load. The
speed difference between the rotor and magnetic field, called slip, s
normally referred to as a percentage of synchronous speed: s = 100
(ns - na)/ns, where s = slip, ns = synchronous speed, and na = actual
speed.

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Post by Thalass » Sun, 30 Nov 2008, 10:46

Great stuff, Ian! Does this mean the MX5 will be at whiteman park tomorrow?


Next project: a 3-phase induction motor controller with support for multiple motors...

I'd buy one!
I'll drive an electric vehicle one day.

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Post by zeva » Sun, 30 Nov 2008, 19:07

Thalass wrote: Great stuff, Ian! Does this mean the MX5 will be at whiteman park tomorrow?


Unfortunately not, the controller isn't running too efficiently yet and would likely overheat on the way!

(Also I've got a motor to drop off on the way, and the MX5 wouldn't be much use there..)
Thalass wrote: Next project: a 3-phase induction motor controller with support for multiple motors... I'd buy one!


Yeah.. one day!
Ian Hooper
--
"Never doubt that the work of a small group of thoughtful, committed citizens can change the world." - Margaret Mead
http://www.zeva.com.au

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