Need help spinning motor using TWR-KV58F220M and TWR-MC-LV3PH

[nathaniel]

Hello,

We are trying to use the TWR-KV58F220M and TWR-MC-LV3PH modules to spin a motor and are currently having trouble trying to get it to run, even with Scalar Control.

We have been able to build and load the PMSM firmware obtained in SDK_2.7.0_TWR-KV58F220M onto the board. We have verified that we can run the Linix Motor included in the kit using MCAT. (i.e. we are able to visualize data and control the Linix motor)

However, we are unable to get the same result with another motor. The motor that we are attempting to use with the development kit is this one:Cobra CM2820. The one thing that stood out to us with this motor is that it is wired in the Delta configuration, instead of a Wye configuration, such as the Linix motor. Maybe this is a clue? We haven't been able to find much information about setting up a delta motor with this platform.

When we try to go through the Motor Identification step in MCAT, we get the following results:

Note how Rs is negative. Also, the motor is giving out a high pitch tone and the identification process seems to be hung up, so we had to manually stop the motor via the application switch.

So the next thing we tried was to manually enter the motor parameters in the Parameters tab, as shown here:

The values for pp and Ke were derived from the "Number of Magnet Poles" and "Motor Kv Value" from the motor specification table, respectively. The Uph nom was lowered to 3V from 15V. Other settings were left unchanged.

After we loaded these setting on to the board, we attempted to run the motor using Scalar Control. One observation that we have is that once the application switch was set to ON, before the Freq_req is set, the motor was producing a buzzing sound. When we set the Freq_req to 100Hz, the Uq_req changes to 0.643V. The motor does not spin and instead in producing an even louder buzzing sound.

Previously, we have tried using the PMSM firmware from MCRSP_PMSM_V1.2.0. However, this version of firmware was causing an over current fault whenever we tried to run the motor.

We have been at this for several days and at this point we need some guidance on the matter. Please let us know if you need more information.

[sunita0685]

Hi, I have been trying the same thing: and just though of posting, as I am also countering the same issue, and if you got any solution or any idea on this.

Got FRDMKV31F control board and interface it with my own 4kW power board and connected to PMSM motor after entering basic motor data Rs,Ld,Lq and current and voltage max. scaling values.

Observed PWM with 10kHz and 0.5us dead time.

With motor connected as soon as I give the required speed command from Free master, DC bus over current comes as a fault.  But when I measure DC bus current its not capturing as any over current or so.

The controller stops at very first pulse or start command.

I am using the MCRSP_PMSM_V1.2.0 PMSM software.

Although I was able to run FRDMKV31F and FRDM PMSM board from NXP with 24V motor provided by NXP, that was running fine, but with my own power board and NXP control kit , there is a issue for dc bus over current fault.

Regards,

Sunita

[joseftkadlec]

Hi Nathaniel,

The motor you are trying to measure has very low resistance (<0.1ohm) and its identification is problematic. Due errors introduced by the inverter measured Rs value might be negative. I such case I recommend not to use the identification and measure motor parameters manually(https://www.nxp.com/docs/en/application-note/AN4680.pdf). There will be no problem for the SW if the motor is wired in Delta or Wye configuration.

Some parameters are updated only during build time. Try to fill your parameters, re-generate m1_pmsm_appconfig.h, re-build in your IDE, download to MCU and finally try Scalar control again. Try to tune V/Hz factor and observe Phase currents in FreeMASTER Recorder (they should be sinusoidal high enough to turn the motor but not to exceed the motor rating or power stage over-current level.

BR,

Josef

[nathaniel]

Hi Josef,

Thanks for the reply.

When making the measurements, do I need to transform the measured values to a Wye configuration?

For example, the stator resistance. In a Wye configuration, according to AN4680, the final stator resistance is half of the measured resistance. So a measured value of 12 Ohms for example, yields a final stator resistance of 6 Ohms.

Now let's say I measured the same stator resistance of 12 Ohms on a Delta configuration motor. Do I use the same 6 Ohms value as the Rs parameter, or do I need to consider the fact that the measured resistance is

Rs = Rmeasured * 3 / 2

Same goes for inductance?

Nathaniel

[joseftkadlec]

Hi Nathaniel,

measure the motor as you wouldn't know its wiring. Assume that it has Wye configuration and make the measurement according to AN4680. When I receive a customer motor I never think about its configuration and measure the motor as it has Wye configuration. Then tune FOC and let me know how it worked, please.

BR,

Josef