Control 4 BLDC Motors with STM32G484

[L_Kopp]

Hello all,

I have an application in which I want to control four BLDC motors independently using the FOC. I want to use a STM32G484 for this. The question now is how I can distribute the interrups so cleverly that I can control all motors with 16kHz without them blocking each other.

Many thanks for your answers :)

 

[Zied b.]

Hi @L_Kopp 
In the solution that we propose on the MCSDK, it is possible to use the STM32G474E-EVAL Board with 2 motors, but the current solution does not offer baords that make more than 2 motors. One of the ideas that I can suggest to you is to use 2 baords and have them communicate by Uart for example. Out of curiosity, can you tell me for which application you need 4 motors?
Regards

[L_Kopp]

Hey @Zied b. 

thank you for your answer. For a first try I can use two Nucleo boards but later I want to design my own board and use only one MCU if possible. Here, as I said, I'm not sure how to get the timings right so that all four motors can be controlled independently.
The application is a mobile robot :)

Regards

[Zied b.]

hi @L_Kopp ,
I can also suggest you look at the B-G431-ESC card, it is possible to control it from a PWM input to vary the speed with the Electronic Speed ​​Control, you can for example have 4 ESCs and one central control card.

 

here is information on how the ESC works: 

 

The electronic speed control (ESC) feature allows to control the motor speed with a PWM signal in input, for example on the B-G431B-ESC1 boards it is possible to use this feature to control the motors of a drone sending a PWM signal with a different duty cycle to switch the motor to armed, armed with a minimum speed, armed with a maximum speed and unarmed state.

You can find more details on this example on this link : click here

[nukersson]

Hello,

I am interested in usage of stm32g4 with x4 stdrive101 to control x4 BLDCs from single MCU with FOC.

My idea for design is to use:

- x3 advaced TIM's with break funktionality and x1 TIM without such to drive one stdrive101 each

- stdrive101 shall provide fixed pwm phase shift for H-bridge protection

- x4 ADC channles with x4 OPAMPs for current sensing on x1 shunt residtor. IMPORTANT: There is no way around one-shunt reistor on H-bridge, since number of OPAMPs is limited to max x8 on one stm32g4.

- x1 TEMP temperature sensor for over-temperature protection

- x1 VBUS sensor for bus voltage sensing

 

Please let me know, if you see some potential pitfalls NO-GO's in mentioned design idea.

Currently I am inspierd by https://www.st.com/en/evaluation-tools/steval-ptool4a.html#cad-resources steval-pool4a schematic design.