SD540 Motor Controller

[philso]

Originally Posted by mindsensors.com

Thank you all for your feedback!

The SD540 is equipped with a battery safety feature that would disable operation when battery voltage drops below 9.5 Volts.

Based on your concerns we have realized that such a safety feature is not desired by the FRC community, so we have released a model that does not include this feature. The new SD540B will work down to 6 Volts without disabling any operations! Here is our voltage comparison chart:
http://www.mindsensors.com/content/7...540-and-sd540b

Since our design and production facility is local and our SD540s are made here in USA, we have the advantage to implement changes quickly. The new model SD540B is available now and ordering information is here: http://www.mindsensors.com/frc/159-sd540-model-b

Originally Posted by AdamHeard

How were you able to "fix" the efficiency issue?

Do you have test data to support this, or just a graph?

If the output voltage of the SB540B is very close to that of the SPARK, it would translate to losses that are about half that of the SD540 (based on the very comprehensive data from CTRE). This is a very dramatic reduction in losses. Most engineers working on inverter designs would sell their grandmothers to get a 5 or 10% increase in efficiency.

Mindsensors - How do the firmware changes for the SD540B (other than removing the undervoltage-lockout safety feature) change it's behaviour relative to the SD540 to account for the increase in efficiency? Has the switching frequency been changed? Have the switching edge rates been changed? Is the heatsink temperatures different? Is the linearity performance the same as for the SD540? I am not expecting you to give away any major trade secrets but there are only so many ways to increase the efficiency of an inverter.

Originally Posted by wilsonmw04

They pointed to their local suppliers and short supply chains in making these changes. I have been in almost daily contact with mindsensor. They are doing everything they can to give the FRC community a solid product. They are new to this space. Give them time.

The motor controllers are mission critical components. The Build Season starts in 2 1/2 weeks. Once a team commits to using a particular controller and builds their robot, they would have very little time to change to a different controller if they are not happy with it.