BOOSTXL-DRV8323RS: The motor does not run with the labs in InstaSPIN Projects

Yi,

Thanks for posting on the MD forum!

Where did you read that you need to install the three capacitors?

Are you able to run lab 2 at all?

Please share your motor datasheet and User.h file.

What voltage is your power supply? What current limit is set?

Regards,

-Adam

Hello Adam,

Thanks for your reply!

1. On this website: 

http://www.ti.com/tool/BOOSTXL-DRV8323RS?keyMatch=DRV8323&tisearch=Search-EN-everything&usecase=part-number 

Technical Documentes -> User guides ->  InstaSPIN™ Quick Start Guide (Rev. A)

I read that I shall solder 3 capacitors.

2. I can build and debug the lab 2a, 2b and 2c without problem. But the labs cannot make the motor run smoothly, which means the motor hums and stops when I set “gMotorVars.Flag_enableSys” and “gMotorVars.Flag_Run_Identify” equal to 1.

3. I use the 48V 6 krpm version of motor PMS100 from the company Heinzmann. The datalog can be found under:

https://www.heinzmann-electric-motors.com/en/products/synchronous-motors-generators/pms-disc-motors

Here is some technical data:

I did not change anything in user.h. You can find my user_j1.h in attachment

4. I supply the board with 24V-DC. The real voltage output during the labs was about 12V.

I increased the current limit and the motor can run!

BUT it took about 10A and burned the cables.

Anyway I can make it run. Thanks! But I need thick cable now.

Is the effect normal or is there still something wrong in my software or hardware?

Do I really need those capacitors?

7446.user_j1.h

Best,

Yi

Problem resolved, thank you so much!

I stumbled on this thread and want to understand the function of these capacitors (C9-11).  What are the associated voltage measurements used for?  To monitor FET voltage drop?  Other than FET voltage drop, it seems we would know the coil voltages from the PWM duty cycle, supply voltage (measured) and shunt voltage (also measured).  

Hello Till,

You can find the answer if you take a look at the schematic of the hardware Boostxl-DRV8323Rx. The schematic is located in

http://www.ti.com/tool/BOOSTXL-DRV8323RS -> Design files -> BOOSTXL-DRV8323RS EVM Hardware Files

There is a MDBU017A(001)_Sch.pdf which shows the schematic as followed:

Here we can see that the capacitors C9 - C11 are used for voltage sensing and the only function of those capacitors is to build a low pass filter for the sensing of phase voltages. I thought the labs could also work without those capacitors because TI does not solder the capacitors on it because the voltage scaling effect is realized via the resistances (R2, R7 ect.)

Hope the information can help you further.

Best,

Yi

Hello Yi,

I agree with you on what the resistive dividers and RC filters do.  Sections 5.2.3 and 5.2.4 of the InstanSPIN User's Guide have some information about the purpose of the voltage measurements and filters:  FAST needs them and expects the voltages to be averages over multiple PWM cycles.

To be honest, I had missed the BOOSTXL-DRV8323 Quick Start Guide's information about placing C9-11.  Perhaps this vital step could have been made more visible (i.e. not sandwiched between Windows screenshots that are not so relevant for Linux users).

Thanks again,

-Till

I'd like to help, but the statement "You can probably run without those caps..." was not true for me (and seemingly also for Yi Zhai).