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Brushless Motor Position Control using Hall sensors

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(@osman)
Eminent Member

Hier Z+ and Z- Channel

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Topic starter Posted : 19/07/2021 9:39 pm
SOLO Team
(@milad)
Chief Member Moderator

@osman

Posted by: @osman

The manufacturer of the motor has contacted me back. And the manufacturer sent me the following last picture below. This picture shows the correct pin assignment. It was a mistake from the manufacturer.

Ok, Great.

Posted by: @osman

I checked my encoder signals afterwards. I got the following results. I get signals from channel A and channel B. But I get no signals from channel Z (see below). Is it normal? I measure only channel B and channel Z or channel A and channel Z in pairs because I have two channel scopes. I took the pictures when the motor was active in sensorless mode.

The Z signal is like a pulse that is generated once every turn, so you should keep monitoring it with your scope ( in Normal or Single trigger mode) and once you turn the shaft 1 turn or More, you should see at least 1 time the Z going from 0 to 5V and then coming back ( a short pulse).

As I see from your calibration results, as the calibration is finished, and you have the values, this means SOLO is detecting the Z signal, and no need to check it further.

Posted by: @osman

I tried to calibrate the motor in spite of the above-mentioned deficiency and got the pictures below.

 

So could you find a combination that works in all Torque, Speed, and Position modes?

Just to add, I see you put the PWM frequency ( switching frequency) at 75kHz, but I believe for your Motor, as it has high inductance, it's better to have a lower frequency like 20-30kHz, high switching frequency is not always good if the internal design of the Motor can not tolerate that ( core saturation resulting in a dramatic reduction of inductance), normally that 75kHz of switching is good for very low inductance motors ( below 100uH).

Regards

Milad

 

If you found the answers helpful and you could solve your problems, please kindly verify here to help others in the future.

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Posted : 20/07/2021 3:02 am
SOLO Team
(@milad)
Chief Member Moderator

@osman

I just noticed another thing:

In your A-B channel captured on scope, I see that A and B signals are not having a stable High state level, as the state level jumping up and down while the signals are at a High state ...

so this can cause issues because the encoder signals are distorted.

if you approve this, I believe you should share the results with the manufacturer of the Motor to understand the reason.

Regards

Milad

 

If you found the answers helpful and you could solve your problems, please kindly verify here to help others in the future.

ReplyQuote
Posted : 20/07/2021 3:23 am
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