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7 years 8 months ago #29527035 by intolubbe
BLDC Cogging? was created by intolubbe
I can find no information regarding Roboteq controllers and BLDC cogging. Is this simply not an issue with your controllers, or does it depend on the type of feedback? I\'m specifically looking at a PERM PMS 150 double sided at 48V with hall feedback. I need precise rpm control driving a small boat propeller up to 1200 rpm; do you know how well the rpm would be controlled with such a load?

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7 years 8 months ago #29527037 by roboteq
Replied by roboteq on topic BLDC Cogging?
Cogging is not an issue with our controllers.

If you want to run at precise and controlled speed, then you will need to operate in close loop speed mode.

The controller can measure speed with good accuracy by timing the transitions on the hall sensors.

Note that speed is measured by measuring the time between hall sensor transitions. This technique will not work well at very low speed. At 1200 RPM it should be fine but we\'d need to know the number of poles of your motor to give a more definitive answer.

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7 years 8 months ago #29527039 by intolubbe
Replied by intolubbe on topic BLDC Cogging?
Our lowest speed would probably be 100rpm. The motor appears to have 4 poles. They mention \"pole pairs\', but I think it is because they have a single and double version of their motors where they just put a second rotor/coil up against the first. Can I have both hall and optical inputs to the controller so I get more pulses per rev for better speed regulation?
If I am using the hall sensors to control the motor, can I run it at a constant power setting? Some of the time we need tight rpm control and other times we would want to run at constant power and let the rpm vary with load. If the controller doesn\'t have that capability, could I write a BASIC script to do it by monitoring motor power and adjusting rpm to keep it at the same power point?

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7 years 8 months ago #29527047 by roboteq
Replied by roboteq on topic BLDC Cogging?
You can write a very simple script that switches between open loop and closed loop upon certain conditions.

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