Current limiting in STM32 for the motor controller

[Karthik DM]

Hello,

I'm working with a BLDC motor controller, I'm currently facing an issue with my current limiting algorithm.

Can anyone please help me with how the current limiting works in the motor controller.

and whats the relationship between RMS current and torque.

[Cristiana SCARAMEL]

Hello @Karthik DM​,

for a better support, could you share more details about your application?

Which hardware are you using?

Which control algorithm are you implementing?

The output torque is directly proportional to the motor current (RMS value) through the KT (constant torque) that is specific to the motor.

Let us know these details and any other information that may be helpful in answering your question.

[Karthik DM]

Hello @Cristiana SCARAMEL​ 

Currently, I'm working with the STM32F302R8Tx controller.

I'm developing six-step motor control logic.

Please tell me more information on current limiting in function

thanks

[Cristiana SCARAMEL · Accepted solution]

Hi @Karthik DM​,

Besides the microcontroller, what other devices are you using to drive the BLDC motor?

For example, motor driver with integrated power stage, or gate drivers with discrete power stage.

In both cases, you can implement a peak current control monitoring the voltage across the shunt resistor (Rs). This power resistor must be connected in a common point with the three low-side power source.

 

The shunt resistor voltage is compared to a reference voltage (Vref) that is proportional to the target current (Ipk-target) with the following equation:

Vref = Rs x Ipk-target

I hope these info can help you.