Current Measurement Discrepancy Between STDRIVE101 + NUCLEO F303RE and Custom Board with STM32F303VC

[Christophe65]

Hello everyone,

I created a project using Motor Control Workbench, configured for FOC with Hall sensors and 3-shunt current sensing, PWM at 20 kHz. The initial setup used:

• NUCLEO F303RE board
• STDRIVE101 evaluation board
• A BLDC motor with a nominal current of 4 A

During testing, everything worked perfectly: the current reading matched the expected load (4 A at constant effort).

Based on this setup, I developed a custom electronic board using an STM32F303VC. The schematic is identical to the EVALSTDRIVE101 board (same components).

I reconfigured the project in MC Workbench using exactly the same parameters as in the evaluation setup. However, when testing the custom board under the same load conditions, I read a current of 8 A.

I’ve double-checked the hardware: shunt resistor values, op-amps, connections — everything is identical. I suspect a configuration issue or a subtle difference I may have overlooked.

Questions:

• Are there any specific parameters in MC Workbench or Motor Pilot that depend on the exact microcontroller model (RE vs VC)?
• Could differences in ADC behavior or internal amplifier gain explain the doubled current reading?
• Has anyone experienced similar issues when switching from ST evaluation boards to custom designs?

Thanks in advance for your help!

Christophe

[GMA]

Hello @Christophe65,

Are the workbench current sensing parameters (gain and shunt resistor) aligned between both projects?
Is the current scaling factor CURRENT_CONV_FACTOR_INV used by Motor Pilot identical?

[Christophe65]

Hello @st_it_Community,

Yes, all current sensing parameters — including gain and shunt resistor values — are identical between both projects. I’ve already checked them multiple times, and I’m currently reviewing everything once again to be absolutely sure.

The value of CURRENT_CONV_FACTOR_INV used by Motor Pilot also appears to be the same, but I’ll re-verify it during this last check.

Thanks again for your support,
Christophe

[federico.rodighiero87]

possible layout or circuit issue, post the schematic.