Cannot start BLDC motor with NUCLEO-L476RG & X-NUCLEO-IHM08M1using MotorControl Workbench 5.Y.2

[MNazir]

Hi everyone,

I am unable to start a Maxon "EC-max 30" BLDC motor (ref 272766) with "NUCLEO-L476RG" development board & "X-NUCLEO-IHM08M1" expansion board using "MotorControl Workbench 5.Y.2" and its corresponding "Motor Pilot 5.Y.2".

1. First of all, the hardware setup of the expansion board was done for FOC control in 3-shunt current sensing topology according to the user manual "UM1996" as well as the motor profiler configuration guidelines (for both the development and the expansion board).
2. For info, the motor parameters could not be identified using "Motor Profiler 5.Y.2" tool as it tries to draw too much current and the identification process could not be finished, so the motor parameters were taken from the datasheet.
3. As for the MC workbench software:

• The bus voltage sensing, temperature sensing, current sensing, over-current protection and power stage parameters were taken from table 7 of the user manual "UM1996".
• The parameters of the motor and its sensor were taken from their respective datasheets (encoder ref 110514).
• As for speed sensing, default parameters were used for the quadrature encoder as the main sensor and the sensorless observer + PLL as auxiliary.
• In analog input and protection section 2.5 ADC clk was used as sampling time for current on ADC1, and 47.5 ADC clk for bus voltage and temperature on ADC2
• MCU and clock freq. section was configured in accordance with figure 73 of the user manual "UM2380".
• The drive settings were configured for position mode control with the PWM frequency, position regulator execution rate, torque & flux execution rate and cut-off frequency chosen such that no FOC duration or overcurrent errors occur.

The result is that I could successfully start & run the motor using "Motor Pilot" as I began to manipulate the gains of the regulators, so the configuration was saved the hardware setup was preserved, the next day I could not get the motor to start anymore as I kept getting an overcurrent message even though no current draw was observed on the power supply which has an even lower current limit than the one allowed in software.

I tried every recommendation in the FAQ to get rid of this problem without success.

When over-current protection is removed, the motor pilot can successfully pass to the RUN state without being able to rotate the motor.

Has anyone faced this problem or has an idea what might be its cause?

Thanks in advance.

[Vijay Ganisetti]

Hi Nazir,

May I know what is the bus voltage??

I had a similar problem with f446re and IHM08m1 3sh boards. Ratings of motor: 36V, 12A, 375W , 3400rpm. Motor profiler works at 24V to measure motor parameters. If bus voltage voltage is 36V, it fails to generate parameters. If directly 36V is applied to motor using workbench, when Click on "Start Motor" in Monitor Screen immediately an "Over current" fault occurs. And motor works under 24V bus-voltage.

Any suggestions are welcome.

Thank You.

Regards,

Vijay

[MNazir]

Hi Vijay,

The bus voltage in my case is 12V which is the nominal voltage supply of the motor so I cannot decrease it much since it should be at least 10V for the expansion board.

Increasing the voltage supply to 24V yields the same results for me. Did you make the necessary hardware modifications for 3 shunt sensing topology? Did you verify the pôwer stage parameters? If you did, try reducing the current regulation loop bandwidth.

Regards,

Mohamad

[Vijay Ganisetti]

Hi Mohamad,

I just made some changes in order to sense the Hall Signals (Replace R79,R81 and R84 with 10k) and R181 is removed. It helps to rotate the motor with 24V DC-bus voltage. However it fails in 36V and shows an "overcurrent" fault.

Regards,

Vijay