Severe Sevcon faults

[IHmk4]

Hi everyone.

I am a motorsport student from London and on my spare time I take part in an electric race bike project.
Previously the project was run by a lecturer who has now left. The bike uses Sevcon Gen4 Size 10.

Long story short - the bike was running ok, with some throttle response issues previously. Then the bike wasn't run for about 3 months after which the bike went on dyno. There is was discovered that throttle seems to have developed more issues - if it's held steady on high current draw or low for couple seconds, power to the motor drops significantly and cannot be recovered until the bike is turned on and off. Another unfortunate side effect is when the throttle response drops sometimes it also locks the rear wheel.

Anyway, I've tried to connect the DVT program to Sevcon through IXXAT, never done this before. When connected, error messages kept coming up, I wasn't able to log in, it kept telling me it's access level is in Timeout. Syntax errors and reading errors have been coming up too when trying to Get the Controller Information or Get Fault Information. Eventually, after many restarts of the program, I was able to get out Fault Information and it gave me two faults - 0x5044 and 0x4F41.
How can I deal with these faults and get the bike running again?
Help!

 

[liveforphysics]

Sevcon is local to you. I would visit them with the bike and see if you can get someone to help you. Tuning a Sevcon is needlessly complex and difficult and counter-intuitive.

 

[zombiess]

Sevcon needs to drop their silly Canbus programming adapter and move to normal USB, it's 2015.

Not sure why their setup is so complex when TI offers instaspin which is stupid simple to tune, they can add all the features they want, even motion control.

 

[IHmk4]

Thanks for your reply guys, I've tried contacting Sevcon, but they won't help me until they find out where the controller was purchased.
As I am involved in the project after everything was gathered and put together and the project leader has left, I cannot find info Sevcon is asking for

 

[Punx0r]

Is this electric bike project funded by the college/uni? If so, you can speak to the accounts depart. The project would likely have its own accounting which can be looked up. Then they can find all invoices for stuff purchased for that project. Hopefully in there will be one for the Sevcon, which would contain details of where it was purchased and when.

 

[Lebowski]

maybe it's time to build your own...

 

[IHmk4]

OK, I've asked a member of staff to look through uni's invoices that they have the access to.
But I got a feeling that luck is not on my side, because the project leader who left had a separate account for the project cause he fell out with uni accounting department when he was running the bike project previously.
Anyway, have to try that.

Meanwhile, would it help to try and terminate CAN bus, to try and get the connection between the IXXAT and Sevcon only?

 

[IHmk4]

Well, Lebowski I would love to build my own and know a guy who did after struggles with Sevcon,
but unfortunately I've never done any kind of programming, software programming or computational integration systems.
I'm just a mechanical engineering student thrown in the deep end. :?

 

[IHmk4]

Another question for anyone who might know the answer:

I have one Gen4 Size 10 on the bike. When there is only one motor controller is it still possible to run it in slave mode?
Or is it only possible when you have two (or more?) controllers on a vehicle where one would run in master mode and the second one in slave?

 

[ARod1993]

Well, Lebowski I would love to build my own and know a guy who did after struggles with Sevcon,
but unfortunately I've never done any kind of programming, software programming or computational integration systems.
I'm just a mechanical engineering student thrown in the deep end. :?

Building your own controller by yourself would be pretty difficult, especially without a programming background. However, there is an option for you that will let you avoid most if not all of the software work and make some of the power electronics design easier. Lebowski has designed and built a field-oriented controller for use on ebikes; it's pretty damn nice feature-wise (including nice things like options for custom throttle curves and the like), you can talk to it directly via serial port as opposed to mucking about with CANBUS protocols or IXXAT equipment), and it's fairly modular (the brain and the power stage can be built separately and then interfaced together). Last I checked, you could buy a preprogrammed brain chip off him for 25 Swiss francs or so, and everything else (including the PCB files and schematics for the brain board) is open source.

Similarly, a member on here known as ZombieSS built a 10-30kW power stage for a Lebowski brain board (100V, 100-300A) for use on his electric bike; while the whole thing is still in testing it looks really promising so far. You'd be playing on a different power level than he would be (if the Sevcon Size 10 specs are anything to go by, you'll want to be able to do 800-900V at 300-500A), but it would be a good starting point. You could probably achieve 900V 400A continuous by building a 36-IGBT version of that power stage using the IXYH82Ns (they're rated for 1200V at 200A continuous apiece, but current ratings from semiconductor companies tend to be incredibly optimistic; the TO-247 package will start suffering damage and fail before the silicon will, and you'd best not push a TO-247 transistor above 60-80A continuous and 100-120A for short bursts), but you'd probably need to mod the layout somewhat to maintain satisfactory insulation with an 800-900V power bus. You'd also need to buy or build some sort of auxiliary DC-DC converter to drop the 800V down to the 60-125V that the brain board and gate drive power supplies are set up to use. None of these problems are insurmountable; they're just an enormous pain in the ass. The question then becomes whether dealing with Sevcon is going to be more of a pain in the ass and/or less rewarding than doing a 400kW Lebowski build.

In case you're interested, just check out Lebowski's megathread for information and setup/fabrication instructions for the brain board, and then ZombieSS's power stage thread for more info on the power stage design. Either way, let us know how it goes!