Run current limitation

[BL1]

Using SPINFamily Evaluation Tool 3.2, STnucleo-f401re and IHM03A1, I try to drive a 48V-9A motor.

In SPINFamily interface, I choosed current mode and tried to set run current to 9A. But an error show up in the interface: "Power dissipation on sense resistor to High for RUN Current".

With run current to 7A, all is working fine, but not higher. Do you know why?

[BL1]

Hi @Cristiana SCARAMEL​ ,

X-NUCLEO-IHM03A1 is designed for

• Voltage range from 10.5V to 85V
• Phase current up to 10Arms

So why is there some physical change to do on the board to be able to reach 9A ?

[Cristiana SCARAMEL]

Hi @BL​,

the mentioned ratings are related to the poweSTEP01 device and not the default setup of the board.

Adjusting the values of the passives, in particular shunt resistance, based on the application targets (both for higher and lower values) is part of the normal hardware design process.

In any case, when working with power devices with high load currents, it is necessary to take into account the ratings of all components and ensure adequate heat dissipation to avoid damage.

So I advise you to change the resistance of shunt and keep the temperature of the board monitored.

Otherwise I suggest you to use the EVLPOWERSTEP01 that from the power dissipation point of view has better performance.

[BL1]

Hi @Cristiana SCARAMEL​ / @MM..1​ ,

Thank you very much for useful help 🙂

[MM..1]

@BL​ for complete clear , maybe you need stop work with 10Amps , when you need ask this questions. Start learn use multimeter, Ohm law and scope.

And FYI 30mA can kill your heart.

[Cristiana SCARAMEL]

Hi @BL​,

Please click on the 'Select as Best' label to close the topic and help other user to find the answer to a similar question.

[BL1]

Hi @Cristiana SCARAMEL​,

One more question about this topic, can it be solved without shunt résistance by using voltage mode?

[Cristiana SCARAMEL]

Hi @BL​,

if you chose the voltage mode driving, you can remove the sense resistors and connect the sense pins directly to ground (refer to Figure 3 of powerSTEP01 datasheet).

When the voltage mode driving is selected the device controls the phase current applying a sinusoidal voltage to motor windings.

Phase current amplitude is not directly controlled but depends on phase voltage amplitude, load torque, motor electrical characteristics and rotation speed.

However, I understand from your new posts that you are carrying on your project in current mode driving.