STOPPING PMSM MOTOR

[jocelync]

Hi,

We are using MCSDK_v5.Y.4. 

We would like to implement Stall Detection and are considering using the measured iq current (used in FOC) for detecting a motor stall. We intend to use a Stall_Detection_Threshold, which is just below the "Current_Limit" to detect when the iq current exceeds this threshold for a given duration of time: stall_time.

We would like to know if the following function, TSK_MF_StopProcessing(), is recommended to use for stopping the motor,

/**

 * @brief Performs stop process and update the state machine.This function

 *    shall be called only during medium frequency task

 */

void TSK_MF_StopProcessing( MCI_Handle_t * pHandle, uint8_t motor)

{

#ifdef REV_1

 R3_2_SwitchOffPWM(pwmcHandle[motor]);

#else

 ICS_SwitchOffPWM(pwmcHandle[motor]);

#endif

 FOC_Clear(motor);

 MPM_Clear((MotorPowMeas_Handle_t*) pMPM[motor]);

 TSK_SetStopPermanencyTimeM1(STOPPERMANENCY_TICKS);

 Mci[motor].State = STOP;

 return;

}

or is there a more immediate "process" or function to use to stop the motor.

From the description in the code, "the MCI_StopMotor() command is used just to begin the

stop motor procedure moving the state to ANY_STOP ". 

Thanks and Best wishes,

Jocelyn

[Gael A · Accepted solution]

Hello jocelync2,

Despite what you said concerning the MCI_StopMotor() command is true, it is nonetheless the safest way (and intended way) to stop a motor. You should have no delay issue and you will be able to easily restart your motor afterwards using the MCI_StartMotor() command.

On a different note, have you tried the latest MCSDK 6.2 version for your project ? It contains many firmware improvement both in stability and performance.

[jocelync]

Hello Gael,

Thank-you very much for your response and your suggestion to upgrade to MCSDK 6.2.

A further question regarding stopping PMSM motors:

          We would like to monitor the angular speed of the PMSM motor:  When the speed increases above a given limit, we would like to stop the motor immediately.

Further Question:   We were wondering where in the MCSDK_v5.Y.4 code, we should perform this monitoring task and then stop the motor when its angular speed exceeds upper limit.    We were thinking of performing this within the function:

                                                 FOC_CurrControllerM1(void),

in mc_tasks.c file, specifically, just before the application of the Torque PI_Controller stage.    The motivation is to perform this check, in a single location in the code (this monitoring of the speed and possibly stopping the motor), where the implementation is applicable for all modes (STC_TORQUE_MODE ,  STC_SPEED_MODE).

Would this be a good location to implement the monitoring and subsequently, stopping of the motor?  or is there a more appropriate location in the code to perform this?

Thanks-in-advance!

Best wishes,

Jocelyn

[Gael A]

Hello jocelync,

The shaft speed is calculated during the MediumFrequencyTask and not the HighFrequencyTask, so I think it would be better to perform your monitoring around (or inside) the CalcAvrgMecSpeedUnit function at the beginning of the MediumFrequencyTask.