[ausev] DIY controller?
Charlesvsi at aol.com
Charlesvsi at aol.com
Sat Jun 14 21:38:44 GMT 2008
Basic functions off the top of my head:
1. sensors monitoring the relationship between accelerator pedal and phase,
amplitude,etc. of current going into motor, while monitoring phase shift of
back emf that indicates how fast electric motor armature is going around.
2. And algorithm that limits current to maximum current drawn from
batteries, and that monitors the voltage of batteries, (Ideally separate readings for
each cell of batteries ) .
3. Then there is regeneration when accelerator pedal is let up some amount,
recharging batteries begins, how much current and how fast to charge to
maintain long life and not overheat ( temperatures of cells monitored too since
battery life is reduced when at high temperatures).
4. And relationship between pressure on and position and rate of change of
accelerator and brake pedals. All related to actual speed of vehicle to apply
an algorithm to get maximum regeneration charge current but with an override
by brake pedal if brakes are needed hard down to prevent a crash.
5. A display system that shows charge voltage level of battery pack, rpm of
electric motor,vehicle speed in mph, forecast of miles to go before needing
6.A circuit to calculate and warn about level of voltage in every cell of
battery so they do not ever get discharged too low and flip over and get
negative charge when charging. Displays to show all this data including red flag
7. A circuit monitoring electric motor speed and temperature so it does
not overheat and run too fast, melting solder, destroying itself, and displays
showing all of the above when needed to warn driver to not do something, etc.
8. The charging circuit from 120 or 240 vac transformed to maximum voltage
needed for battery charge, rectified to DC, and then circuits monitoring and
then reducing ac input to not over charge batteries. And a display to show
that it is all working.
Probably more, but these are the same elements needed in Aircraft auto
pilots, except we only need input and control on one horizontal axis instead of 3
axis for airplaines.
9. Probably a yaw or turn sensor to keep vehicle from turning too fast with
power on to roll over, based on the amount of unsprung weight on wheels and
axles, and the springing and shock absorber dynamics so it does not yaw
itself off of the road.
I worked on the design of the B52 and Boeing 727 autopilots, but that was in
the 60's, so I probably don't remember a few details.
Good luck with the controller.
In a message dated 6/14/2008 8:42:41 A.M. Central Daylight Time,
evehicle4me at hischopsticks.org writes:
What are the "basic functions" that a controller needs to manage?
Quoting Charlesvsi at aol.com:
> Good luck on DYI, We have a Honda Civic Hybrid, I'm amazed at all the
> the computer does so well.
> I was in Process Control Computer Systems for 38 years, The control
> software is very complicated, especially in life or death
> applications like cars.
> Hopefully you can find some inexpensive controller, with sensors
> etc, and menu
> driven software, so it will run all the basic functions, you will just h
> to provide specific information about your vehicle etc.
> Have fun. C.
> Chuck Simms
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