I like to know why can not read the motor parameters from my evaluation board STEVAL-SPIN3202 using the ST Motor Profiler software and i need to buy an new board B-G431B-ESC1?

[SVlac.1]

My company develop a new BLDC Drive board in order to control a BLDC Motor For use in automatic doors mechanism.

i attach the datasheet of the motor. The electrical parameters of motor is the following:

1. Number of polar pairs : 2

2.Max.application speed: 4000 rpm

3.Nominal Current :1.5Apk

4.Nomianl DC voltage:24v

5. Rs in 3.54 Ohm.

6. Ls in 9.06 mH.

7. B-Emf constant in Vms/Krpm N/A

8.Nominal Torque is 0.048N.m and stall torque torque is 12N.m

9.Nominal current is 1.3A and stall current is 5A

10.Nominal speed is 4000rpm and stall speed is 2800

11.Motor's rotor is possitioned through the hall effect switch and the angle is 60°

it is critical the parameter B-Emf constant in order to make the motor spinning successfully? Do I need to buy the B-G431B-ESC1 board only to measure this parameter using the ST Motor Profiler software?

It is possible to have a assistance from any expert to fill all the right parameters at MotorControl Workbench 5.4.6 software to make the above motor working normally?

How to overcome the StartUp Failure Error?

Thank You in advance

Stamatis Vlachos

[Dario CUCCHI]

Hello @SVlac.1​ ,

My suggestion is not to buy a new board just for measuring the B-Emf constant of the motor.

Usually it is possible to measure the B-Emf constant rotating the motor shaft and measuring the voltage on the phases.

But, you are using a motor with a reduction gearbox, so it would be difficult to rotate from external the motor shaft.

In this case, you can estimate the B-emf, in this way:

1. Estimate the torque constant as the ratio between the rated torque and the rated current.
2. the B-Emf constant in V/(rad/s) is equal to the torque constant (in Nm/A).

Using the data reported in the datasheet you get:

BEMF constant = 0.048 Nm / 1.3A = 0.037 Nm/A = 0.037 V/(rad/s)

Since you need the value in Vrms/Krpm you need to convert this value according to the equivalence: 1 rad/s = 9.55 rpm, 1 V = 0.707 Vrms.

You can get the B-Emf constant = 2.74 Vrms/krpm

This is an estimation, but you can refine it once the motor is running.

About the Startup Failure error, you have to focus on other parameters, apart from the BEMF constant.

I think the number of pole pairs is the most critical value.

Then, you listed some electrical parameters of the motor, that are not reported in the attached datasheet.

Did you measured them or do you have other technical document about this motor ?

Are Ls, and Rs the phase-to-phase values or are they referred to the central tap of the windings ?

How did you setup the Start-up parameters in the Firmware Drive Management block of the workbench ?

If you can share some more details about your project it would be helpful.

[Laurent Ca...]

The question has been moved from the section "Motor Control Hardware" to the "STM32 Motor Control" section (the question is about the STM32 MC SDK). 

Best regards