Sunday in review (the Greenstage Gathering)

We had a great turnout on Sunday, with people coming and going all day long.  Plenty of EVs onsite with people just dropping in to show off their cars and others coming to see what's happening and what's possible for them.  This is exactly what we like to see!

Greenstage Gathering 2012

The underlying community focus and vision from Greenstage (and the associated Open Source technology projects, Tumanako and SolarNetwork) is explained within the 2012 flyer, please download this and share it around or have a look at the image below.

Greenstage Community Focus

Mid afternoon we demonstrated the SolarNetwork enabled charging pedestal in action, we showed how this facilitates the sharing of existing charging infrastructure amongst EV owners.  People registered with the SolarNetwork can enable other peoples charging pedestals anywhere around the country (assuming the owners of the pedestal have granted permission for this).  They do this using the Android based Tumanako Dashboard which uses wireless communications to activate the charging pedestal (as well as activating charging pedestals, this dashboard also monitors your EV performance while driving). 

Tumanako Dashboard

This is a very low cost way of creating a charging network that grows as demand grows (every EV owner already installs some form of charging infrastructure at home, so even if only 50% of EV owners join the network, this will easily create a nationwide distributed EV charging infrastructure).

Community Charging

Not to be outdone, Chris Olsen announced the Energy Share co-op to great excitement.  Already it's obvious that people have been hanging out for this and that the co-op is going to be a game changer with respect to personal energy independence.  You can download more information on EnergyShare from here and if you are ready to join and get involved, please fill in the online form.

So all in all it was a great day.  Lots of learning, lots of fun and lots of opportunity for everyone.  I know I haven't covered everything, but please feel free to share your thoughts and experiences in the comments section below, the more we share the more everyone benefits.

Finally, these gatherings don't happen on their own, its the community that brings it all together.  So a big thanks to Grey Lynn Dogs, Switch EV, Electrex, Stewart Design, Diamond Age Solutions, Andrew Simms Mitsubishi, Andy Harper Tyres, APEV, ECONZ, Athol, Warren, Jeremy, Steve and Dee, Tom and Tabitha, my wife Kirstin, Dylan Aimee and Sophie, plus all the Greenstage crew and their families for making this happen, it wouldn't happen without you.

Exciting times ahead, the technology is ready, the community is growing and we are all eager for change.

Lets make it happen!

Greenstage Gathering 2012

Yes, it's time for another Greenstage gathering!

It's a one day event being held from 10am till 3pm, on Sunday 18th November at 19 Newton Rd in Auckland (head down Newton Rd from Khyber Pass Rd, it's just past the North Western motorway over-bridge on the left, just before you get to Ponsonby Rd).  Parking is available in the nearby back streets and pay and display parking is available on the corner of Karangahape Rd and Gundy St.

As well as having a bit of fun and showing off a few grouse EVs, the purpose of the gathering is to launch new clarity around desirable positive actions we can collectively and individually take to make life more enjoyable, less costly and overall better for everyone and the environment.

The Future is Now:

1) it's desirable
2) it's community focused
3) it's knowledge driven (and fuelled by sharing)
4) it's high tech and high performance!
5) and it's a whole lot of FUN!

Here's some of what will be happening on the day:

• Join the launch of a distributed energy Co-op (sign up for cheaper renewable power)
• Meet Vik and the RepRap fabricating physical Open Source components (print your own objects!)
• Talk to the experts about photovoltaic systems with storage and SolarNetwork monitoring and control
• See and learn about the Greenstage GS750V (now with high performance race battery)
• Talk with the owner of the Switch EV Ute (NZ designed and built electric induction motor, controller and instrumentation!)
• Learn about the Tumanako Dashboard (controlling SolarNetwork EV charge points from an Android phone)
• See the ScottDrive powered Honda Prelude (exceptional NZ designed and built motor controller and powerstage!)
• See the Switch EV Toyota Celica (a very tidy conversion, powered by solar generated electricity - no fuel bills)
• Marvel at the Tesla Roadster (Yes! The world's leading high performance electric road car)
• Consider the Nissan Leaf  (a very practical mid sized EV)
• Investigate the Mitsubishi i-MiEV (a nice 4 seat EV)
• Drink Coffee (it's Sunday morning)
• Eat solar hotdogs (weather permitting)
• Listen to live Music!!! (Grey Lynn dogs and more)

In addition to the look point and talk discussions and conversations in the carpark, there will be a number of scheduled presentations indoors:

• 11:30 am - The RepRap, Vik builds a casing for the KiwiAC bluetooth module (which is used to talk wirelessly with the Tumanako Dashboard)
• 12:30 pm - Co-op Launch
• 1:30 pm - Tumanako Dashboard (Android powered EV dashboard and charge controller)

Please email if you plan on coming along (we need a rough idea of numbers), also, if you have any ideas or suggestions to make the event even better.

Let us know!

Switch EV is go! (part 3)

The Greenstage Team has been helping Switch EV with final tuning and testing on their Electric Holden Ute.  We decided to capture some of the action and we have put together a little montage, with a hint to what's coming next as well.



If you're after more information, check out earlier Switch EV blog posts part 1 and part 2.

Enjoy!

KiwiAC driving Switch EV Induction motor … Part 2: Motor Control

Following on from our bench testing earlier in June, Switch EV have installed their motor into their test vehicle and undergone some driveway testing. Sorry no video or photos this time, just output logs turned into pretty graphs (go LibreOffice!)
At the most basic level we are controlling motor current. Our serial output is not fast enough to report every current measurement (two performed every 12kHz), but we can see if the current is behaving within the region we expect. First we can compare the requested current output magnitude, vs raw, directly sampled phase currents. The vertical axis is a signed internal scale, where 32700 is approximately 1000 Amps.

Here you can see that every reported current is within the magnitude requested. Because of stroboscopic effects, (sampling windows and AC sinusoidal waveforms etc) it is expected that we would see values less than requested current.

Delving into the Motor Model at the heart of Field Oriented Control, we can check that the two current vectors, (magnetic flux producing Id and torque producing Iq) are controlling:  

Here, the error between requested Id and Iq are plotted as DId and Diq. The error is around 1%, which equates to a output Torque error of about 0.01% (output Torque is proportional to motor flux times torque current).
At the moment, we are controlling Flux and Torque to equal throttle position (thick grey line). Flux (the green line) should always be positive however, (as two negative numbers would multiply to a positive torque). We have set the throttle zero position to produce regen torque, to approximate engine braking, but only while moving. You can see at 175 seconds when the vehicle was stopped that the torque and flux trending to zero, no longer following the throttle position. A small acceleration occurs from 184-193 seconds, and a much greater one at 205 seconds.

This final graph shows power in the controllers DC bus, versus the calculated mechanical motor power (estimated torque times motor speed) and an estimation of the inverter and motor AC conduction losses. At the time the car was traversing undulating terrain, so change in speed does not correspond that well to delivered power.
Finally, a big thanks to Lachlan for putting together the data extraction scripts that made these graphs possible and to Switch EV for building such a great EV!
Stay tuned, driving videos coming soon...

KiwiAC driving Switch EV Induction motor

We have recently been helping to commission a new induction motor made be Switch EV (a NZ manufacturer).  We are pretty happy with the results so far and hope to be showing vehicle based dyno (dynamometer) results in the near future. For now though, here are some videos and images to whet your appetite.

The motor shown is being driven via a Gen 1 SKAI with a Greenstage KiwiAC control board and a 330V Lithium Iron Phosphate battery pack providing the energy.

As you can see the brake rotor on the dyno gets quite hot (hence the smoke!), it is absorbing the energy from the motor when we load it up to measure the torque.

Zero RPM torque tests showed we were achieving in excess of 600 Nm, which is "heaps" of torque and matching nicely with design goals.  Unfortunately the dyno didn't quite measure up and soon after we snapped the shear pin on the shaft.

Never mind, the dyno did its job and the Switch EV motor is ready for the next stage!  Stay tuned for more information...