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Unable to achieve maximum RPM with my motor

Other Parts Discussed in Thread: DRV8301, BOOSTXL-DRV8301, DRV8301-69M-KIT, LAUNCHXL-F28069M, LAUNCHXL-F28027F

Hi,

I have a 780kV rated motor with 14 poles, with 14.8V bus voltage as its supply. The maximum speed it can achieve is 11,544RPM, but I am unable to exceed 8000RPM. There is also a very noticeable sound coming from the motor when running beyond 5000RPM. I am assuming I have incorrect parameter values in my user.h, limiting the maximum speed it can achieve. Can someone help me identify potential problems?

Thanks.


My user.h:

//! \brief CURRENTS AND VOLTAGES
// **************************************************************************
//! \brief Defines the full scale frequency for IQ variable, Hz
//! \brief All frequencies are converted into (pu) based on the ratio to this value
//! \brief this value MUST be larger than the maximum speed that you are expecting from the motor
#ifndef QEP
#define USER_IQ_FULL_SCALE_FREQ_Hz        (1463.0)   // 800 Example with buffer for 8-pole 6 KRPM motor to be run to 10 KRPM with field weakening; Hz =(RPM * Poles) / 120
#else
#define USER_IQ_FULL_SCALE_FREQ_Hz        (USER_MOTOR_NUM_POLE_PAIRS/0.008)   // (4/0.008) = 500 Example with buffer for 8-pole 6 KRPM motor to be run to 6 KRPM; Hz = (RPM * Poles) / 120
#endif

//! \brief Defines full scale value for the IQ30 variable of Voltage inside the system
//! \brief All voltages are converted into (pu) based on the ratio to this value
//! \brief WARNING: this value MUST meet the following condition: USER_IQ_FULL_SCALE_VOLTAGE_V > 0.5 * USER_MOTOR_MAX_CURRENT * USER_MOTOR_Ls_d * USER_VOLTAGE_FILTER_POLE_rps,
//! \brief WARNING: otherwise the value can saturate and roll-over, causing an inaccurate value
//! \brief WARNING: this value is OFTEN greater than the maximum measured ADC value, especially with high Bemf motors operating at higher than rated speeds
//! \brief WARNING: if you know the value of your Bemf constant, and you know you are operating at a multiple speed due to field weakening, be sure to set this value higher than the expected Bemf voltage
//! \brief It is recommended to start with a value ~3x greater than the USER_ADC_FULL_SCALE_VOLTAGE_V and increase to 4-5x if scenarios where a Bemf calculation may exceed these limits
//! \brief This value is also used to calculate the minimum flux value: USER_IQ_FULL_SCALE_VOLTAGE_V/USER_EST_FREQ_Hz/0.7
#define USER_IQ_FULL_SCALE_VOLTAGE_V      (16)   // 24.0 Example for drv8301_revd typical usage and the Anaheim motor

//! \brief Defines the maximum voltage at the input to the AD converter
//! \brief The value that will be represented by the maximum ADC input (3.3V) and conversion (0FFFh)
//! \brief Hardware dependent, this should be based on the voltage sensing and scaling to the ADC input
#define USER_ADC_FULL_SCALE_VOLTAGE_V       (66.32)      // 66.32 drv8301_revd voltage scaling

//! \brief Defines the voltage scale factor for the system
//! \brief Compile time calculation for scale factor (ratio) used throughout the system
#define USER_VOLTAGE_SF               ((float_t)((USER_ADC_FULL_SCALE_VOLTAGE_V)/(USER_IQ_FULL_SCALE_VOLTAGE_V)))

//! \brief Defines the full scale current for the IQ variables, A
//! \brief All currents are converted into (pu) based on the ratio to this value
//! \brief WARNING: this value MUST be larger than the maximum current readings that you are expecting from the motor or the reading will roll over to 0, creating a control issue
#define USER_IQ_FULL_SCALE_CURRENT_A          (42.0)   // 41.25 Example for drv8301_revd typical usage

//! \brief Defines the maximum current at the AD converter
//! \brief The value that will be represented by the maximum ADC input (3.3V) and conversion (0FFFh)
//! \brief Hardware dependent, this should be based on the current sensing and scaling to the ADC input
#define USER_ADC_FULL_SCALE_CURRENT_A        (82.5)     // 82.5 drv8301_revd current scaling

//! \brief Defines the current scale factor for the system
//! \brief Compile time calculation for scale factor (ratio) used throughout the system
#define USER_CURRENT_SF               ((float_t)((USER_ADC_FULL_SCALE_CURRENT_A)/(USER_IQ_FULL_SCALE_CURRENT_A)))

//! \brief Defines the number of current sensors used
//! \brief Defined by the hardware capability present
//! \brief May be (2) or (3)
#define USER_NUM_CURRENT_SENSORS            (3)   // 3 Preferred setting for best performance across full speed range, allows for 100% duty cycle

//! \brief Defines the number of voltage (phase) sensors
//! \brief Must be (3)
#define USER_NUM_VOLTAGE_SENSORS            (3) // 3 Required

#define   I_A_offset    (0.975757658)
#define   I_B_offset    (0.981840134)
#define   I_C_offset    (0.980548680)

//! \brief ADC voltage offsets for A, B, and C phases
//! \brief One-time hardware dependent, though the calibration can be done at run-time as well
//! \brief After initial board calibration these values should be updated for your specific hardware so they are available after compile in the binary to be loaded to the controller
#define   V_A_offset    (0.411259115)
#define   V_B_offset    (0.411382854)
#define   V_C_offset    (0.413100541)


//! \brief CLOCKS & TIMERS
// **************************************************************************
//! \brief Defines the system clock frequency, MHz
#define USER_SYSTEM_FREQ_MHz             (90.0)

//! \brief Defines the Pulse Width Modulation (PWM) frequency, kHz
//! \brief PWM frequency can be set directly here up to 30 KHz safely (60 KHz MAX in some cases)
//! \brief For higher PWM frequencies (60 KHz+ typical for low inductance, high current ripple motors) it is recommended to use the ePWM hardware
//! \brief and adjustable ADC SOC to decimate the ADC conversion done interrupt to the control system, or to use the software Que example.
//! \brief Otherwise you risk missing interrupts and disrupting the timing of the control state machine
#define USER_PWM_FREQ_kHz                (60.0) //30.0 Example, 8.0 - 30.0 KHz typical; 45-80 KHz may be required for very low inductance, high speed motors

//! \brief Defines the maximum Voltage vector (Vs) magnitude allowed.  This value sets the maximum magnitude for the output of the
//! \brief Id and Iq PI current controllers.  The Id and Iq current controller outputs are Vd and Vq.
//! \brief The relationship between Vs, Vd, and Vq is:  Vs = sqrt(Vd^2 + Vq^2).  In this FOC controller, the
//! \brief Vd value is set equal to USER_MAX_VS_MAG*USER_VD_MAG_FACTOR.  Vq = sqrt(USER_MAX_VS_MAG^2 - Vd^2).
//! \brief Set USER_MAX_VS_MAG = 1.0 for a pure sinewave with a peak at SQRT(3)/2 = 86.6% duty cycle.  No current reconstruction is needed for this scenario.
//! \brief Set USER_MAX_VS_MAG = 2/SQRT(3) = 1.1547 for a pure sinewave with a peak at 100% duty cycle.  Current reconstruction will be needed for this scenario (Lab10a-x).
//! \brief Set USER_MAX_VS_MAG = 4/3 = 1.3333 to create a trapezoidal voltage waveform.  Current reconstruction will be needed for this scenario (Lab10a-x).
//! \brief For space vector over-modulation, see lab 10 for details on system requirements that will allow the SVM generator to go all the way to trapezoidal.
#define USER_MAX_VS_MAG_PU        (1.0)    // Set to 1.0 if a current reconstruction technique is not used.  Look at the module svgen_current in lab10a-x for more info.


//! \brief Defines the Pulse Width Modulation (PWM) period, usec
//! \brief Compile time calculation
#define USER_PWM_PERIOD_usec       (1000.0/USER_PWM_FREQ_kHz)

//! \brief Defines the Interrupt Service Routine (ISR) frequency, Hz
//!
#define USER_ISR_FREQ_Hz           ((float_t)USER_PWM_FREQ_kHz * 1000.0 / (float_t)USER_NUM_PWM_TICKS_PER_ISR_TICK)

//! \brief Defines the Interrupt Service Routine (ISR) period, usec
//!
#define USER_ISR_PERIOD_usec       (USER_PWM_PERIOD_usec * (float_t)USER_NUM_PWM_TICKS_PER_ISR_TICK)


//! \brief DECIMATION
// **************************************************************************
//! \brief Defines the number of pwm clock ticks per isr clock tick
//!        Note: Valid values are 1, 2 or 3 only
#define USER_NUM_PWM_TICKS_PER_ISR_TICK        (3)

//! \brief Defines the number of isr ticks (hardware) per controller clock tick (software)
//! \brief Controller clock tick (CTRL) is the main clock used for all timing in the software
//! \brief Typically the PWM Frequency triggers (can be decimated by the ePWM hardware for less overhead) an ADC SOC
//! \brief ADC SOC triggers an ADC Conversion Done
//! \brief ADC Conversion Done triggers ISR
//! \brief This relates the hardware ISR rate to the software controller rate
//! \brief Typcially want to consider some form of decimation (ePWM hardware, CURRENT or EST) over 16KHz ISR to insure interrupt completes and leaves time for background tasks
#define USER_NUM_ISR_TICKS_PER_CTRL_TICK       (1)      // 2 Example, controller clock rate (CTRL) runs at PWM / 2; ex 30 KHz PWM, 15 KHz control

//! \brief Defines the number of controller clock ticks per current controller clock tick
//! \brief Relationship of controller clock rate to current controller (FOC) rate
#define USER_NUM_CTRL_TICKS_PER_CURRENT_TICK   (1)      // 1 Typical, Forward FOC current controller (Iq/Id/IPARK/SVPWM) runs at same rate as CTRL.

//! \brief Defines the number of controller clock ticks per estimator clock tick
//! \brief Relationship of controller clock rate to estimator (FAST) rate
//! \brief Depends on needed dynamic performance, FAST provides very good results as low as 1 KHz while more dynamic or high speed applications may require up to 15 KHz
#define USER_NUM_CTRL_TICKS_PER_EST_TICK       (1)      // 1 Typical, FAST estimator runs at same rate as CTRL;

//! \brief Defines the number of controller clock ticks per speed controller clock tick
//! \brief Relationship of controller clock rate to speed loop rate
#define USER_NUM_CTRL_TICKS_PER_SPEED_TICK  (15)   // 15 Typical to match PWM, ex: 15KHz PWM, controller, and current loop, 1KHz speed loop

//! \brief Defines the number of controller clock ticks per trajectory clock tick
//! \brief Relationship of controller clock rate to trajectory loop rate
//! \brief Typically the same as the speed rate
#define USER_NUM_CTRL_TICKS_PER_TRAJ_TICK   (15)   // 15 Typical to match PWM, ex: 10KHz controller & current loop, 1KHz speed loop, 1 KHz Trajectory

//! \brief Defines the controller frequency, Hz
//! \brief Compile time calculation
#define USER_CTRL_FREQ_Hz          (uint_least32_t)(USER_ISR_FREQ_Hz/USER_NUM_ISR_TICKS_PER_CTRL_TICK)

//! \brief Defines the estimator frequency, Hz
//! \brief Compile time calculation
#define USER_EST_FREQ_Hz           (uint_least32_t)(USER_CTRL_FREQ_Hz/USER_NUM_CTRL_TICKS_PER_EST_TICK)

//! \brief Defines the trajectory frequency, Hz
//! \brief Compile time calculation
#define USER_TRAJ_FREQ_Hz          (uint_least32_t)(USER_CTRL_FREQ_Hz/USER_NUM_CTRL_TICKS_PER_TRAJ_TICK)

//! \brief Defines the controller execution period, usec
//! \brief Compile time calculation
#define USER_CTRL_PERIOD_usec      (USER_ISR_PERIOD_usec * USER_NUM_ISR_TICKS_PER_CTRL_TICK)

//! \brief Defines the controller execution period, sec
//! \brief Compile time calculation
#define USER_CTRL_PERIOD_sec       ((float_t)USER_CTRL_PERIOD_usec/(float_t)1000000.0)


//! \brief LIMITS
// **************************************************************************
//! \brief Defines the maximum negative current to be applied in Id reference
//! \brief Used in field weakening only, this is a safety setting (e.g. to protect against demagnetization)
//! \brief User must also be aware that overall current magnitude [sqrt(Id^2 + Iq^2)] should be kept below any machine design specifications
#define USER_MAX_NEGATIVE_ID_REF_CURRENT_A     (-0.5 * USER_MOTOR_MAX_CURRENT)   // -0.5 * USER_MOTOR_MAX_CURRENT Example, adjust to meet safety needs of your motor

//! \brief Defines the low speed limit for the flux integrator, pu
//! \brief This is the speed range (CW/CCW) at which the ForceAngle object is active, but only if Enabled
//! \brief Outside of this speed - or if Disabled - the ForcAngle will NEVER be active and the angle is provided by FAST only
#define USER_ZEROSPEEDLIMIT   (1.0 / USER_IQ_FULL_SCALE_FREQ_Hz)     // 0.002 pu, 1-5 Hz typical; Hz = USER_ZEROSPEEDLIMIT * USER_IQ_FULL_SCALE_FREQ_Hz

//! \brief Defines the force angle frequency, Hz
//! \brief Frequency of stator vector rotation used by the ForceAngle object
//! \brief Can be positive or negative
#define USER_FORCE_ANGLE_FREQ_Hz   (USER_ZEROSPEEDLIMIT * USER_IQ_FULL_SCALE_FREQ_Hz)      // 1.0 Typical force angle start-up speed

//! \brief Defines the maximum current slope for Id trajectory during PowerWarp
//! \brief For Induction motors only, controls how fast Id input can change under PowerWarp control
#define USER_MAX_CURRENT_SLOPE_POWERWARP   (0.3*USER_MOTOR_RES_EST_CURRENT/USER_IQ_FULL_SCALE_CURRENT_A/USER_TRAJ_FREQ_Hz)  // 0.3*RES_EST_CURRENT / IQ_FULL_SCALE_CURRENT / TRAJ_FREQ Typical to produce 1-sec rampup/down

//! \brief Defines the starting maximum acceleration AND deceleration for the speed profiles, Hz/s
//! \brief Updated in run-time through user functions
//! \brief Inverter, motor, inertia, and load will limit actual acceleration capability
#define USER_MAX_ACCEL_Hzps                 (20.0)      // 20.0 Default

//! \brief Defines maximum acceleration for the estimation speed profiles, Hz/s
//! \brief Only used during Motor ID (commission)
#define USER_MAX_ACCEL_EST_Hzps           (14.0)         // 5.0 Default, don't change

//! \brief Defines the maximum current slope for Id trajectory during estimation
#define USER_MAX_CURRENT_SLOPE           (USER_MOTOR_RES_EST_CURRENT/USER_IQ_FULL_SCALE_CURRENT_A/USER_TRAJ_FREQ_Hz)      // USER_MOTOR_RES_EST_CURRENT/USER_IQ_FULL_SCALE_CURRENT_A/USER_TRAJ_FREQ_Hz Default, don't change

//! \brief Defines the fraction of IdRated to use during rated flux estimation
//!
#define USER_IDRATED_FRACTION_FOR_RATED_FLUX (1.0)      // 1.0 Default, don't change

//! \brief Defines the fraction of IdRated to use during inductance estimation
//!
#define USER_IDRATED_FRACTION_FOR_L_IDENT    (1.0)      // 1.0 Default, don't change

//! \brief Defines the IdRated delta to use during estimation
//!
#define USER_IDRATED_DELTA                  (0.00002)

//! \brief Defines the fraction of SpeedMax to use during inductance estimation
//!
#define USER_SPEEDMAX_FRACTION_FOR_L_IDENT  (1.0)      // 1.0 Default, don't change

//! \brief Defines flux fraction to use during inductance identification
//!
#define USER_FLUX_FRACTION           (1.0)            // 1.0 Default, don't change

//! \brief Defines the PowerWarp gain for computing Id reference
//! \brief Induction motors only
#define USER_POWERWARP_GAIN                   (1.0)         // 1.0 Default, don't change

//! \brief Defines the R/L estimation frequency, Hz
//! \brief User higher values for low inductance motors and lower values for higher inductance
//! \brief motors.  The values can range from 100 to 300 Hz.
#define USER_R_OVER_L_EST_FREQ_Hz (300)               // 300 Default


//! \brief POLES
// **************************************************************************
//! \brief Defines the analog voltage filter pole location, Hz
//! \brief Must match the hardware filter for Vph
#define USER_VOLTAGE_FILTER_POLE_Hz  (335.648)   // 335.648, value for drv8301_revd hardware

//! \brief Defines the analog voltage filter pole location, rad/s
//! \brief Compile time calculation from Hz to rad/s
#define USER_VOLTAGE_FILTER_POLE_rps  (2.0 * MATH_PI * USER_VOLTAGE_FILTER_POLE_Hz)

//! \brief Defines the software pole location for the voltage and current offset estimation, rad/s
//! \brief Should not be changed from default of (20.0)
#define USER_OFFSET_POLE_rps            (20.0)   // 20.0 Default, do not change

//! \brief Defines the software pole location for the flux estimation, rad/s
//! \brief Should not be changed from default of (100.0)
#define USER_FLUX_POLE_rps              (100.0)   // 100.0 Default, do not change

//! \brief Defines the software pole location for the direction filter, rad/s
#define USER_DIRECTION_POLE_rps             (6.0)   // 6.0 Default, do not change

//! \brief Defines the software pole location for the speed control filter, rad/s
#define USER_SPEED_POLE_rps           (100.0)   // 100.0 Default, do not change

//! \brief Defines the software pole location for the DC bus filter, rad/s
#define USER_DCBUS_POLE_rps           (100.0)   // 100.0 Default, do not change

//! \brief Defines the convergence factor for the estimator
//! \brief Do not change from default for FAST
#define   USER_EST_KAPPAQ               (1.5)   // 1.5 Default, do not change

// **************************************************************************
// end the defines


//! \brief USER MOTOR & ID SETTINGS
// **************************************************************************

//! \brief Defines the default bandwidth for SpinTAC Control
//! \brief This value should be determined by putting SpinTAC Control through a tuning process
#define USER_SYSTEM_BANDWIDTH_SCALE    (1.0)

//! \brief Define each motor with a unique name and ID number
// BLDC & SMPM motors
#define Estun_EMJ_04APB22           101
#define Anaheim_BLY172S             102
#define Teknic_M2310PLN04K          104
#define T_MOTOR_MN3110_15_780         105
// IPM motors
// If user provides separate Ls-d, Ls-q
// else treat as SPM with user or identified average Ls
#define Belt_Drive_Washer_IPM       201

// ACIM motors
#define Marathon_5K33GN2A           301

//! \brief Uncomment the motor which should be included at compile
//! \brief These motor ID settings and motor parameters are then available to be used by the control system
//! \brief Once your ideal settings and parameters are identified update the motor section here so it is available in the binary code
//#define USER_MOTOR Estun_EMJ_04APB22
//#define USER_MOTOR Anaheim_BLY172S
//#define USER_MOTOR Teknic_M2310PLN04K
//#define USER_MOTOR Belt_Drive_Washer_IPM
//#define USER_MOTOR Marathon_5K33GN2A
#define USER_MOTOR T_MOTOR_MN3110_15_780

#if (USER_MOTOR == T_MOTOR_MN3110_15_780)                  // Name must match the motor #define
#define USER_MOTOR_TYPE                 MOTOR_Type_Pm  // Motor_Type_Pm (All Synchronous: BLDC, PMSM, SMPM, IPM) or Motor_Type_Induction (Asynchronous ACI)
#define USER_MOTOR_NUM_POLE_PAIRS       (7)            // PAIRS, not total poles. Used to calculate user RPM from rotor Hz only
#define USER_MOTOR_Rr                   (NULL)         // Induction motors only, else NULL
#define USER_MOTOR_Rs                   (0.06772009)     // Identified phase to neutral resistance in a Y equivalent circuit (Ohms, float)
#define USER_MOTOR_Ls_d                 (2.58498e-5)  // For PM, Identified average stator inductance  (Henry, float)
#define USER_MOTOR_Ls_q                 (2.58498e-5)  // For PM, Identified average stator inductance  (Henry, float)
#define USER_MOTOR_RATED_FLUX           (0.007918171)         // Identified TOTAL flux linkage between the rotor and the stator (V/Hz)
#define USER_MOTOR_MAGNETIZING_CURRENT  (NULL)         // Induction motors only, else NULL
#define USER_MOTOR_RES_EST_CURRENT      (3.0)          // During Motor ID, maximum current (Amperes, float) used for Rs estimation, 10-20% rated current
#define USER_MOTOR_IND_EST_CURRENT      (-1.0)         // During Motor ID, maximum current (negative Amperes, float) used for Ls estimation, use just enough to enable rotation
#define USER_MOTOR_MAX_CURRENT          (20)         // CRITICAL: Used during ID and run-time, sets a limit on the maximum current command output of the provided Speed PI Controller to the Iq controller
#define USER_MOTOR_FLUX_EST_FREQ_Hz     (135.0)         // During Motor ID, maximum commanded speed (Hz, float), ~10% rated
#define USER_MOTOR_ENCODER_LINES        (1.0)       // Number of lines on the motor's quadrature encoder
#define USER_MOTOR_MAX_SPEED_KRPM       (10.0)          // Maximum speed that the motor
#define USER_SYSTEM_INERTIA             (0.0606352)         // Inertia of the motor & system, should be estimated by SpinTAC Velocity Identify
#define USER_SYSTEM_FRICTION            (0.0428040)         // Friction of the motor & system, should be estimated by SpinTAC Velocity Identify

#else
#error No motor type specified
#endif

#ifndef USER_MOTOR
#error Motor is not defined in user.h
#endif

#ifndef USER_MOTOR_TYPE
#error The motor type is not defined in user.h
#endif

#ifndef USER_MOTOR_NUM_POLE_PAIRS
#error Number of motor pole pairs is not defined in user.h
#endif

#ifndef USER_MOTOR_Rr
#error The rotor resistance is not defined in user.h
#endif

#ifndef USER_MOTOR_Rs
#error The stator resistance is not defined in user.h
#endif

#ifndef USER_MOTOR_Ls_d
#error The direct stator inductance is not defined in user.h
#endif

#ifndef USER_MOTOR_Ls_q
#error The quadrature stator inductance is not defined in user.h
#endif

#ifndef USER_MOTOR_RATED_FLUX
#error The rated flux of motor is not defined in user.h
#endif

#ifndef USER_MOTOR_MAGNETIZING_CURRENT
#error The magnetizing current is not defined in user.h
#endif

#ifndef USER_MOTOR_RES_EST_CURRENT
#error The resistance estimation current is not defined in user.h
#endif

#ifndef USER_MOTOR_IND_EST_CURRENT
#error The inductance estimation current is not defined in user.h
#endif

#ifndef USER_MOTOR_MAX_CURRENT
#error The maximum current is not defined in user.h
#endif

#ifndef USER_MOTOR_FLUX_EST_FREQ_Hz
#error The flux estimation frequency is not defined in user.h
#endif


// **************************************************************************
// the functions


//! \brief      Sets the user parameter values
//! \param[in]  pUserParams  The pointer to the user param structure
extern void USER_setParams(USER_Params *pUserParams);


//! \brief      Checks for errors in the user parameter values
//! \param[in]  pUserParams  The pointer to the user param structure
extern void USER_checkForErrors(USER_Params *pUserParams);


//! \brief      Gets the error code in the user parameters
//! \param[in]  pUserParams  The pointer to the user param structure
//! \return     The error code
extern USER_ErrorCode_e USER_getErrorCode(USER_Params *pUserParams);


//! \brief      Sets the error code in the user parameters
//! \param[in]  pUserParams  The pointer to the user param structure
//! \param[in]  errorCode    The error code
extern void USER_setErrorCode(USER_Params *pUserParams,const USER_ErrorCode_e errorCode);


//! \brief      Recalculates Inductances with the correct Q Format
//! \param[in]  handle       The controller (CTRL) handle
extern void USER_softwareUpdate1p6(CTRL_Handle handle);


//! \brief      Updates Id and Iq PI gains
//! \param[in]  handle       The controller (CTRL) handle
extern void USER_calcPIgains(CTRL_Handle handle);


//! \brief      Computes the scale factor needed to convert from torque created by Ld, Lq, Id and Iq, from per unit to Nm
//! \return     The scale factor to convert torque from (Ld - Lq) * Id * Iq from per unit to Nm, in IQ24 format
extern _iq USER_computeTorque_Ls_Id_Iq_pu_to_Nm_sf(void);


//! \brief      Computes the scale factor needed to convert from torque created by flux and Iq, from per unit to Nm
//! \return     The scale factor to convert torque from Flux * Iq from per unit to Nm, in IQ24 format
extern _iq USER_computeTorque_Flux_Iq_pu_to_Nm_sf(void);


//! \brief      Computes the scale factor needed to convert from per unit to Wb
//! \return     The scale factor to convert from flux per unit to flux in Wb, in IQ24 format
extern _iq USER_computeFlux_pu_to_Wb_sf(void);


//! \brief      Computes the scale factor needed to convert from per unit to V/Hz
//! \return     The scale factor to convert from flux per unit to flux in V/Hz, in IQ24 format
extern _iq USER_computeFlux_pu_to_VpHz_sf(void);


//! \brief      Computes Flux in Wb or V/Hz depending on the scale factor sent as parameter
//! \param[in]  handle       The controller (CTRL) handle
//! \param[in]  sf           The scale factor to convert flux from per unit to Wb or V/Hz
//! \return     The flux in Wb or V/Hz depending on the scale factor sent as parameter, in IQ24 format
extern _iq USER_computeFlux(CTRL_Handle handle, const _iq sf);


//! \brief      Computes Torque in Nm
//! \param[in]  handle          The controller (CTRL) handle
//! \param[in]  torque_Flux_sf  The scale factor to convert torque from (Ld - Lq) * Id * Iq from per unit to Nm
//! \param[in]  torque_Ls_sf    The scale factor to convert torque from Flux * Iq from per unit to Nm
//! \return     The torque in Nm, in IQ24 format
extern _iq USER_computeTorque_Nm(CTRL_Handle handle, const _iq torque_Flux_sf, const _iq torque_Ls_sf);


//! \brief      Computes Torque in lbin
//! \param[in]  handle          The controller (CTRL) handle
//! \param[in]  torque_Flux_sf  The scale factor to convert torque from (Ld - Lq) * Id * Iq from per unit to lbin
//! \param[in]  torque_Ls_sf    The scale factor to convert torque from Flux * Iq from per unit to lbin
//! \return     The torque in lbin, in IQ24 format
extern _iq USER_computeTorque_lbin(CTRL_Handle handle, const _iq torque_Flux_sf, const _iq torque_Ls_sf);


#ifdef __cplusplus
}
#endif // extern "C"

//@} // ingroup
#endif // end of _USER_H_ definition

  • what lab are you using? you should use 2c to ID and then 10a to run so you can tune the speed controller and apply over-modulation to hit higher speeds.

    your parameters look very reasonable for these motors
    #define USER_MOTOR_Rs (0.06772009) // Identified phase to neutral resistance in a Y equivalent circuit (Ohms, float)
    #define USER_MOTOR_Ls_d (2.58498e-5) // For PM, Identified average stator inductance (Henry, float)
    #define USER_MOTOR_Ls_q (2.58498e-5) // For PM, Identified average stator inductance (Henry, float)
    #define USER_MOTOR_RATED_FLUX (0.007918171)


    in your user.h, this value is too large.
    #define USER_IQ_FULL_SCALE_FREQ_Hz (1463.0)

    You should only set this up to 4x the
    #define USER_VOLTAGE_FILTER_POLE_Hz (335.648)
    so I would choose something like (1300.0)
    it's ok if your actual frequency is slightly higher.

    how are you tuning your speed controller?
  • also, in the future please don't copy/paste the user.
    instead drag/drop the file into the reply window so that it will attach
  • another comment
    - are you doing this test with no load / propeller?
    - do you have enough current (I assume you are using batteries, so yes)
  • and yet another comment...
    I notice you are using the DRV8301 EVM. This EVM doesn't have the cleanest current sense layout. It can get very noise with higher PWM frequencies and at higher modulation (rotor frequency). Although the BOOSTXL-DRV8301 is only 10A continuous, I much prefer to use this for initial eval of these small hobby motors with such low inductance / poor current ripple motors.
  • Thanks for the quick reply Chris,

    "also, in the future please don't copy/paste the user.

    instead drag/drop the file into the reply window so that it will attach"

    Sorry, thanks for the reminder!


    "You should only set this up to 4x the
    #define USER_VOLTAGE_FILTER_POLE_Hz (335.648)
    so I would choose something like (1300.0)
    it's ok if your actual frequency is slightly higher."

    I have taken your advice and changed the value, but just out of curiosity, would this affect the maximum speed the motor can run up to?

    "- are you doing this test with no load / propeller?
    - do you have enough current (I assume you are using batteries, so yes)"

    Yes, there is no load applied to the motor during the tests. Yes there is enough current as well.

    ChrisClearman said:
    and yet another comment...
    I notice you are using the DRV8301 EVM. This EVM doesn't have the cleanest current sense layout. It can get very noise with higher PWM frequencies and at higher modulation (rotor frequency). Although the BOOSTXL-DRV8301is only 10A continuous, I much prefer to use this for initial eval of these small hobby motors with such low inductance / poor current ripple motors.


    Yes, I'm currently using the DRV8301-69M-KIT. According to my motor's manufacturer, it requires 14.9A of current to reach 9000 RPM (a target speed I would like to reach). Can this be performed using the BOOSTXL-DRV8301?


    I redid Lab 2c again, and I updated the values in my user.h (f2806xF). I then proceeded to Lab 10a and ran the motor, but I was unable to exceed 1200RPM without experiencing some jittering (the speed feedback shows the speed fluctuating between 500 RPM to 1700 RPM). Have I set some of my parameters too high in my user.h?

    8371.user.h

  • "I have taken your advice and changed the value, but just out of curiosity, would this affect the maximum speed the motor can run up to?"
    not exactly. but by keeping the FREQUENCY < 4 * FILTER_POLE you are avoiding a variable overflow which can cause serious system stability issues.

    "requires 14.9A of current to reach 9000 RPM (a target speed I would like to reach). Can this be performed using the BOOSTXL-DRV8301? "
    No, the BOOST can only do 10A continuous, 14A peak.

    "but I was unable to exceed 1200RPM without experiencing some jittering (the speed feedback shows the speed fluctuating between 500 RPM to 1700 RPM)"

    Have you tuned your speed controller? how? If you are having trouble I suggest you try InstaSPIN_motion proj_lab05c - 5f to use the SpinTAC controller. Simpler to tune and excellent performance.

    besides that I would say the culprit would be in poor current measurement data into the system at high speeds / high modulation. This could be corrected with better HW layout for current sense.
  • Thank you for the help Chris.

    Regarding the BOOSTXL_DRV8301, I read that it is not a standalone evaluation kit, and it requires a compatible LaunchPad XL. I'm quite interested in the BoosterPack, so what LaunchPad XL can I use and which one would be the most ideal? Also, I'm located in the UK, if I want to buy the BoosterPack, do I buy it from the site or is there a UK based supplier that I can buy it from? [Considering the shipping cost and the time needed... :((((]


    ChrisClearman said:


    Have you tuned your speed controller? how? If you are having trouble I suggest you try InstaSPIN_motion proj_lab05c - 5f to use the SpinTAC controller. Simpler to tune and excellent performance.

    I have tried doing Lab 5a and 5b, and I obtained values of,


    Ki series (PU): 0.133

    Kp series (PU): 0.438

    Truth be told, for Lab 5b's calculations, I was quite confused as to how to get the value for the time constant of the velocity filter low pass filter, . For J, the inertia, can I use the value found in Lab 5c? From Lab 5c, I got 0.0606352 As/krpm as the value for the inertia, and then I converted it, ended up with 2.264e-5 kg.m^2.

    I will try the 5c-5f again tomorrow and update you on my findings. Am I right to assume that tuning the SpinTAC velocity controller only requires tuning the BWscale (Lab 5e)?

  • for the boosterpack you can use LAUNCHXL-F28069M or LAUNCHXL-F28027F both are in stock with TI eStore as well as distribution partners like Digikey and Mouser.

    In lab05b what are the default values for the speed Kp and Ki? What values are you then replacing these with?

    For these high speed motors, to do no load testing a good starting point is to usually divide the default values by 10.

    I agree the equations/write-up for the speed controller tuning are hard to follow. It's complex and I find that manual trial and error testing typically works well enough. You can also try the SpinTAC controller as it works quite well and very simple to try different tunings with yes - just the single variable.
  • ChrisClearman said:
    In lab05b what are the default values for the speed Kp and Ki? What values are you then replacing these with?

    Default Spd_Kp and Spd_Ki values were 12.4 and 0.0464 respectively. I reduced the values by a factor of 10. It does seem rather time consuming and difficult to get good values through trial and error, because the motor goes crazy and the jittering noise becomes absurdly loud if the input number is slightly off, so I guess I am struggling to pinpoint 'good' values for Spd_Kp and Spd_Ki, especially when they vary with the motor's speed (just for a confirmation, as I increase the value for the referenced speed, in order to maintain a somewhat 'stable' performance, I have to decrease the Spd_Kp and Spd_Ki further. Is this correct?)


    I have been doing Lab 5c-5e, and I still get roughly the same values for inertia and friction as my previous test results. For 5e, the instruction was "Make sure the motor is at zero speed by setting “gMotorVars.SpeedRef_krpm” to 0. Once the motor is at zero speed, manually rotate the motor shaft with your hand to feel how tightly the motor is holding zero, this is an indication of how aggressively the motor is tuned... Once the SpinTAC Velocity Control is tightly holding zero the bandwidth scale has been tuned." I increased the bandwidth scale by increments of 1.0; BW scale higher than 4.0 causes the motor to oscillate, and turning the motor manually by a small angle results in the motor spinning shortly in the opposite direction. I can actually feel the vibration when I touch the motor. For 1000RPM to 2000RPM, I set the BW scale to 3.0, and everything was ok. Increasing the speed > 2000 RPM, and the motor makes the jittering noise. The guide says set the speed reference as the maximum motor speed, when I attempted with 9000 RPM, the speedfeed back only shows 5000, and the jittering noise is very loud. Reducing the BW scale by 10-15% didn't solve the issue. I'm not quite sure how to proceed from this.

    ChrisClearman said:
    for the boosterpack you can use LAUNCHXL-F28069M or LAUNCHXL-F28027F both are in stock with TI eStore as well as distribution partners like Digikey and Mouser.


    So if I get a LAUNCHXL-F28069M and the BOOSTXL-DRV8301, will I then be able to fully evaluate my motor? (If I use another rotor blade, I can achieve even higher RPM while requiring less current, so 14A peak current is not an issue.) How does my current kit (DRV8301-69M-KIT) fare against LAUNCHXL-F28069M + BOOSTXL-DRV8301, regarding their capabilities with high PWM frequencies and modulation?

  • Yau Tsang said:

     The guide says set the speed reference as the maximum motor speed, when I attempted with 9000 RPM, the speedfeed back only shows 5000, and the jittering noise is very loud.


    UPDATE: I tried again, and I set the RPM to 9000, and the motor is able to reach 7850 RPM, with less jittering noise than 5000~7000 RPM. I remember reading somewhere in Lab 4 that when I set the IqRef to a high enough value, the motor will spin to its full speed (voltage limited). I re-attempted Lab 4, and when the Iq is set as 0.5, the motor's RPM is shown to be 7850. Does that mean 14.8 voltage (my battery's maximum voltage) is not sufficient to be able to drive the motor to 9000 RPM since 7850 is the full voltage limited speed?

  • when you set the speed ref higher than it can achieve your speed controller is saturating to it's maximum output, allowing the Iq_Ref to be it's maximum output. This makes the controller stable. When you are commanding a speed <7850 the control is becoming unstable because the reference and the feedback are not matching and/or the controller is not tuned well (it's probably too stiff and is hunting, commanding a high torque, then a lot, then a high, then a low...).

    the voltage being applied to the motor is not sufficient to reach 9000 RPM. You can try using proj_lab10a where you can adjust your modulation up to a value of 1.33, putting 33% more voltage onto the motor and increasing your speed. This is showing in the LaunchPad + BoosterPack training videos in section 5:

    www.ti.com/.../support_community.shtml
  • IMHO (I'm just learning too), you indeed seem to be hitting the voltage limit.

    Remember that for FOC, you need to apply a sinusoidal waveform to your motor. With the peak voltage 1.4 times the RMS value of the voltage. So you need a slightly (1.4 times) higher powersupply voltage to achieve the same maximum RPM as when the motor is driven "old fashioned" with a trapezoidal waveform.
  • Thank you Chris and Roger for the help! I can successfully reach the max speed by using field weakening and by changing the modulation to 1.33. I've been conducting tests with my newly arrived Launchxl-F28069m and BOOSTXL-DRV8301, and there are significantly less noise, and tuning the motor appears to be easier too (Lab 5b).


    Many thanks,


    Yau