BoostXL-DRV8301 as parallel driver with DRV8301-LS31-KIT

Alan Lindner

Other Parts Discussed in Thread: BOOSTXL-DRV8301, DRV8301

I have added a BoostXL-DRV8301 as a second parallel motor drive to the DRV8301-LS31-KIT. So I am trying to control two motors with one set of PWM signals from the MCU. The regular motor output of the DRV8301-LS31-KIT connected to the supplied Teknic M2310 motor and works fine.

Jumper wires are attached to the J5 connector to the BoostXL board. Attachment is as follows:

DRV8301	PIN	BoostXL
J5-6	EN_GATE	J4-15
J5-9	FAULTn	J3-6
J5-12	OCTWh	J3-8
J5-13	DC_CAL	J4-17
J5-22	PWM_CL	J4-12
J5-23	PWM_AL	J4-4
J5-24	PWM_AL	J4-8
J5-25	PWM_AL	J4-2
J5-26	PWM_CH	J4-10
J5-28	PWM_BH	J4-6
J5-39	GND	J3-3
J5-40	GND	J4-1

As can be seen, all the outputs of the MCU to the DRV8301 are connected but not all the return signals fromt he DRV8301 to the MCU. I am basing the sensorless measurements from one motor.

Please identify what signals must be connected for operation and which ones don't have to be.

Thanks

Alan

over 11 years ago

0 ChrisClearman over 11 years ago

TI__Guru** 119680 points

Alan,

I don't understand.

Alan Lindner said:
but not all the return signals fromt he DRV8301 to the MCU. I am basing the sensorless measurements from one motor.

You are trying use the feedback from the DRV8301 EVM motor to drive the motor connected to BOOSTXL motor? This will never work

0 Alan Lindner over 11 years ago in reply to ChrisClearman

Intellectual 500 points

Yes, I am trying to drive two identical motors that are physically connected together yet electrically only having the sensorless feedback from one motor. The two motors only share the PWM signals. Theoretically this should work but in the real workd???

0 ChrisClearman over 11 years ago in reply to Alan Lindner

TI__Guru** 119680 points

theoretically this will NOT work

the rotor position of one motor has nothing to do with the rotor position of the other (whether you are doing 6-step commutation or field oriented control)

0 Alan Lindner over 11 years ago in reply to ChrisClearman

Intellectual 500 points

Chris,

I understand and agree if they are separate motors. But if this case, the windings are being separated so it is the same shuttle, just driving different parts of the stator. Would that then work?

0 ChrisClearman over 11 years ago in reply to Alan Lindner

TI__Guru** 119680 points

Alan,

I don't follow the mechanics of what you're saying. Do you have a picture/sketch of this motor(s)?

0 Alan Lindner over 11 years ago in reply to ChrisClearman

Intellectual 500 points

Chris,

Attached is a picture of a motor where there are two sets of 'Y' windings that would be driven driven separately.

So one H-bridge connects to Phase A, B and C. A second H-bridge connects to Phase A-2, B-2 and C-2. There would only be one rotor. The PWM signal would go to both driver chips but the sensorless current feedback would only come from one.

Alan

0 ChrisClearman over 11 years ago in reply to Alan Lindner

TI__Guru** 119680 points

I assume you mean two 3-ph inverters,not H bridge, correct?

These stators are only connected to a common ground, correct? I would think that for 6-step BLDC your switching patterns for the 2nd would need to be phase shifted by 60 degrees or else you will be energizing coils that aren't helping you generate torque. But I'm not sure how this second stator effects the Bemf that you sense only on one stator set.

Sorry, this is very unusual and we don't have any experience with this type of motor.

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BoostXL-DRV8301 as parallel driver with DRV8301-LS31-KIT