Quote:
Originally Posted by bennelson
I also noticed that the "whine" seems to happen at around 250 amps while accelerating, NOT when maxing out the ammeter.
We need to investigate this "hurkey-jerky" thing the controller does while starting accelerating. It feels like the car doesn't know if it wants to go or not. From the drivers point of view, it's just not a good thing.
Also, anything we can do to "unleash" the amperage with this controller is good. I like on the Curtis that you can use a pot to adjust your throttle response and power output.
Overall, the controller is very nice. I'm mostly comparing it to the Curtis and Alltrax controllers that I have experience with.
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Are you measuring battery amps or motor amps? The current limiting is happening when motor amps goes over 500 (according to the current sensor), and the battery amps is the MOTOR_AMPS*PWM_DUTY. So, at low duty, you can have low battery amps, but very high motor amps. Actually, that's another reason why we need to get the signal cleaned up out of the current sensor! If there's a 15 or 20% error on the current sensor reads, then the hardware current shutdown might be coming on anywhere in the motor amps range of 400 to 500.
And another reason to clean up that signal!!! I'm using the current to limit throttle. So, if I'm trying to set the current so that it matches the throttle position, and the dang current sensor is spazzing out, +/- 20% error! haha! You are going to feel the "not sure if it wants to go or not" phenomenon. It wouldn't be the same issue at higher RPM, because the motor current would change more slowly, because of the inductance, so I'm thinking it would be more accurate current sensor reads then.
I have gotten some really good suggestions about how to fix it. In fact, I might be able to fix it without any new components added to your controller, Ben. I'm almost done with version 1.000001 (few changes from the previous one, so I can drive to the alternative energy fair in a couple weeks, and use my car once again!), and I'm going to try some software ideas that have been sent my way. I could then send you that chip, and you could take off the top of the controller, and plug in the new one, and see if there is any improvement at the low RPM.