DRV8323: ??

omer yaffe

Part Number: DRV8323
Other Parts Discussed in Thread: DRV8245-Q1, DRV8262, , DRV8706-Q1

Tool/software:

Hi,

I am a control engineer and currently working on designing a current loop for DC motors. My objective is to implement a current loop with a bandwidth (BW) of 1 kHz and subsequently build speed and position loops on top of it.

I would like to consult about the required operating rate for the current loop and the design of building the measured current input for the PID controller. I am attaching the DRV8323H datasheet for reference. The available hardware enables the measurement of two phases on the low side with an analog bandwidth of 1 MHz.

Specifically, I would like to ask:

Would you recommend filtering the measured voltages with an analog bandwidth of 10 kHz?

How should the current feedback be calculated in each iteration for optimal performance?

I would greatly appreciate your advice on how to approach this design effectively.

My implemntation of the position, velocity and current controller will be based on the simulink.

Best regards,

Omer.

3 months ago

0 Yara Al Shami 3 months ago

TI__Genius 10985 points

Hi Omer,

omer yaffe said:
Would you recommend filtering the measured voltages with an analog bandwidth of 10 kHz?

Yes, a 10 kHz analog filter bandwidth is would be a good choice. It is significantly higher than your current loop bandwidth of 1 kHz, ensuring noise reduction without introducing excessive phase lag. This balance is crucial for maintaining loop stability and performance.

omer yaffe said:
How should the current feedback be calculated in each iteration for optimal performance?

Here are some resources that might help you answer this question:

https://www.ti.com/video/6216805428001#transcript-tab

https://www.ti.com/lit/an/bpra048/bpra048.pdf

I think it also might be helpful to see the firmware that is used on the launchpads for the EVMs, feel free to download them off of our EVM's webpage

Regards,

Yara

0 omer yaffe 3 months ago in reply to Yara Al Shami

Prodigy 10 points

Hi, i asked on DC brushed motors. you provided me information on the FOC commutation which is relevant for the BLDC motors.

I want to build current control loop based on the two currents sense in the low side which i have in the circuit.

All of my questions are related to this goal.

Thanks a lot again for the help,

Omer.

0 Yara Al Shami 3 months ago in reply to omer yaffe

TI__Genius 10985 points

Hi Omer,

Thank you for clarifying this is for a brushed motor application. I'm not entirely familiar with using this devices for a brushed application so I'll be reaching out to my team for help on this one. I'll provide an update soon.

Regards,

Yara

0 Jacob Thompson 3 months ago in reply to Yara Al Shami

TI__Mastermind 23250 points

Hey Omer,

If this is a brushed DC motor I recommend using a Brushed DC Motor driver instead of a BLDC motor driver. Brushed DC (BDC) motor drivers product selection | TI.com I recommend looking at DRV8262 or DRV8245-Q1 if you need high power. Both of these have integrated current sensing within the driver itself, if the accuracy is good enough for you. Else you're welcome to continue using external current sense amplifiers.

How much current and voltage do you need on this BDC motor? I see the DRV8323 you picked is a 65V gate driver, here are our gate drivers: Brushed DC (BDC) motor drivers product selection | TI.com - check out DRV8706-Q1

Here's some more detail on the integrated current sensing in our BDC drivers: (+) [FAQ] How to configure IPROPI and current sensing - Motor drivers forum - Motor drivers - TI E2E support forums

As for the filtering, that will depend on your application. For BDC motors most customers do not implement any filtering like you mention.

Does that help answer your question?

Best,

Jacob