Updates appended to bottom of page
2. Power Inverter
June 1 2008 update:
I think we are close to delivery, maybe a week or two, we'll see.
Good news, the dimensions have been reduced in each axis since I had created the model used for original fitting. That makes this job basically a done deal. It's a perfect fit.
At the same time, I was able to workout the coolant plumbing sequence/routing for all 4 components that share the cooling system.
August 30 2008 update:
The inverter is mounted:
This mount is secure. All axis are firmly supported to prevent mechanical resonance.
The Drive motor will fill the hole below with 3/4 inch minimum clearance around it's body.
Because of the limited access to the left side mounts at the rear of this inverter box, I moved the mount points to be just below the inverter with the pre-mounted support seen below.
The 3 holes along the bottom edge of this support have pressed in stainless PEM nuts so the installation into the motor compartment is very simple, with or without the drive motor mounted.
I machined notches into the 1/2 inch 6061 ALU plate that supports the steel tabs on the inverter. This prevents the side loading on the mounting bolts.
Without the inverter mounted, you can see the right hand mount points for the inverter. The cross bar supports the inverter in that axis and allows for a nice wiring support path
The holes in these little brackets for wiring will allow cinching down with zip ties.
A close up of a wiring support arm being welded on
Power Inverter Update March 14, 2009
Temporary Inverter installation - Siemens 100kW Simotion drive inverter
Here is the new plan to get the BMW on the road while waiting for the 200kW drive unit:
I will make a new set of ALU brackets to custom mount these two enclosures to the same chassis tie points, making them interchangeable.
I will be making a lower profile cover for this contactor box, getting 1 inch to allow this fit.
All the plumbing and big wire paths are clear and accessible. Luck happens.
This has the originally planned clearance for the battery pack so it will be fully compatible.
The wires come out from the right of contactor box in ideal path to connect with my pack.
I will configure the pack for 350V drive system while using this inverter.
May 2009 Update:
This 200kW Inverter has not been completed and the Dutch company Evisol has run out of money while debugging their SW/HW problems.
The new investors have personally pledged to repay or deliver after new development restart but is just words rather than any guarantee.
At this point, those of us that invested in this product are not sure if or when they will deliver anything that will make our Inverter hardware functional.
Original Plan : .... delayed for redesign of the DSP board
July 2009 Update:
Things are looking up for the inverter SW design. There are multiple design efforts now going in parallel with this very capable power stage hardware.
This is one of those things that I did not plan to spend time engineering, but some times you have to take matters into you own hands... On the bright side, this forces the understanding of this critical element of the drive system that will certainly have big payback on future projects.
Oct 2009 Update:
While the development is progressing, I have been able to get a sponsorship from a local company with some AC motor drive systems coming on the market: Rinehart Motion Systems at www.rinehartmotion.com
The motor is in their hands now for setting up the inverter and confirming by testing.
I will then make a simple adaptor to attach it to the mount system already in place for the 200kW drive unit.
March 30 2010 Update:
The recent bench testing all went perfectly and finally, a fully installed Inverter:
Everything is installed/wired/plumbed. The only thing missing from this view is the battery pack, which hides everything when installed... This Inverter(blue box) is a compact 100kW AC Induction motor drive control which has HV IGBT devices allowing for my 700V Lithium Ion battery system. With this 100kW inverter, the 660V nominal operating voltage will lower the current demand from the battery modules to a mere 150 Amps, only 22% of the cell module's continuous output rating of 700 Amps(1200A for 10 sec peak). These cells will just be "idling" under full power.
I am not sure if I have mentioned this but, the pack is spec 'd to deliver 684HP (based on 1000 amp @ 510V output, 204s10p configuration-still only 80% of peak). The new "weak link" is now the motor. So take this as a hint: motors are progressing well in power/weight and packaging, allowing another 2x power delivery in same space. A new generation of IPM brushless is nearing production that will be part of my next development, adding significantly to continuous power output levels and torque, delivered into a 4WD sport machine for best traction/regen braking.
The 200kW Inverter SW redesign is progressing well also. The motor is spinning on the bench under new control system. Victor at MetricMind.com, (where I purchased it) is committed to remedy Evisol's development problem with eventual working result using original excellent HW drive electronics. Once ready, it will easily drop it into this vehicle in its originally planned form.
April 6 2010 Update:
And finally with the cowling installed as well as cooling and hydraulic fluids topped off,
Ready to install the battery pack..
