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DC Generator - Chopper Circuit - PWM Control

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Forum 1
(@fingerprint)
New Member
Topic starter
 

Hi SOLO,

 

I would like to know if the on-board brake chopper can actively control/tune the power created by a brushed DC generator.

 

We need to actively control the torque required to rotate a DC generator with a varying analog PWM signal based on its speed.

 

Reading through the User Manual, I understand you can set the activation voltage with a set resistor value based on your provided formula.

From my understanding, this will only short circuit the DC motor when the power generated creates a voltage over the set activation voltage and then begin dissipating energy until it drops below that level.

 

Does the SOLO board have a MOSFET or equivalent high speed switch that we can access to control when the brake chopper is short circuited?

 
Posted : 28/06/2022 8:59 pm
SOLO Team
(@milad)
Illustrious Member Admin
 

Hi @fingerprint,

Posted by: @fingerprint

From my understanding, this will only short circuit the DC motor when the power generated creates a voltage over the set activation voltage and then begin dissipating energy until it drops below that level.

Exactly.

Posted by: @fingerprint

Does the SOLO board have a MOSFET or equivalent high speed switch that we can access to control when the brake chopper is short circuited?

The Brake circuit on SOLO has a MOSFET and an analog voltage detection circuit, so whenever the voltage of the BUS surpasses the limit that is set, the Mosfet will conduct the current through the Shunt resistor (shorting is Drain to Source) while the shunt resistor is connected in between the Positive line of the Bus and the Drain of the Mosfet, regarding your question, to control the regeneration you needed to have access to the Gate of the Mosfet, and unfortunately, such input doesn't exist now on SOLO UNO_v2, so if you want to fully control the regeneration, you need to install an external circuitry on the BUS line.

Let me know if you have any other questions.

Milad

 

 

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

 
Posted : 30/06/2022 7:03 am
Forum 1
(@fingerprint)
New Member
Topic starter
 

Hi Milad,

 

Thanks for the reply.

if you want to fully control the regeneration, you need to install an external circuitry on the BUS line

By external circuitry, do you mean use an independent board with, for example, a MOSFET and NCP driver etc. ?

you needed to have access to the Gate of the Mosfet

By access, do you mean physically or with digitally? There is no way to send commands through the BUS into the SOLO UNO to control the gate?

 

Cheers

 
Posted : 07/07/2022 12:30 am
SOLO Team
(@milad)
Illustrious Member Admin
 

@fingerprint

Posted by: @fingerprint

By external circuitry, do you mean use an independent board with, for example, a MOSFET and NCP driver etc. ?

That's right, so by that, I meant to control the regeneration completely externally using circuitry that comes on top of the VBUS and conserves/dissipates the extra energy independently from the chopper brake circuit on SOLO.

Posted by: @fingerprint

By access, do you mean physically or with digitally? There is no way to send commands through the BUS into the SOLO UNO to control the gate?

Yes, the circuit there is completely independent of the DSP on board, thus it can not be controlled by external commands or by a motion terminal.

Regards
Milad

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

 
Posted : 08/07/2022 10:23 am
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