> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/vedderb/bldc/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuration parameters

> Reference for all key mc_configuration parameters with their default values from mcconf_default.h.

All parameters belong to the `mc_configuration` struct defined in `datatypes.h`. Default values are set in `motor/mcconf_default.h` and can be overridden per hardware target.

<Note>
  Hardware-specific builds may override any of these defaults. The values shown here are the firmware-wide defaults that apply when no hardware override is present.
</Note>

## Current limits

| Parameter                 | Default        | Description                                                                       |
| ------------------------- | -------------- | --------------------------------------------------------------------------------- |
| `l_current_max`           | `60.0 A`       | Maximum motor phase current (upper limit).                                        |
| `l_current_min`           | `-60.0 A`      | Minimum motor phase current (lower limit, negative for braking).                  |
| `l_in_current_max`        | `99.0 A`       | Maximum input (battery) current draw.                                             |
| `l_in_current_min`        | `-60.0 A`      | Minimum input current (negative = regen current back into battery).               |
| `l_abs_current_max`       | `130.0 A`      | Hard absolute current limit — triggers `FAULT_CODE_ABS_OVER_CURRENT` immediately. |
| `l_current_max_scale`     | `1.0`          | Scale factor applied to `l_current_max` at runtime.                               |
| `l_current_min_scale`     | `1.0`          | Scale factor applied to `l_current_min` at runtime.                               |
| `l_in_current_map_start`  | `1.0`          | Input current to Q-axis current limit map start threshold.                        |
| `l_in_current_map_filter` | `0.005`        | Low-pass filter constant for the mapped input current limit.                      |
| `l_watt_max`              | `1,500,000 W`  | Maximum output power. Set to a practical value for the drive system.              |
| `l_watt_min`              | `-1,500,000 W` | Minimum output power (maximum braking power).                                     |

<Warning>
  Setting `l_abs_current_max` above the hardware current rating can destroy MOSFETs. Always set this below the gate driver and FET peak current specification.
</Warning>

## Voltage limits

| Parameter                   | Default    | Description                                                                                      |
| --------------------------- | ---------- | ------------------------------------------------------------------------------------------------ |
| `l_min_vin`                 | `8.0 V`    | Minimum input voltage — triggers `FAULT_CODE_UNDER_VOLTAGE` below this.                          |
| `l_max_vin`                 | `57.0 V`   | Maximum input voltage — triggers `FAULT_CODE_OVER_VOLTAGE` above this.                           |
| `l_battery_cut_start`       | `10.0 V`   | Input voltage at which positive current output begins to ramp down.                              |
| `l_battery_cut_end`         | `8.0 V`    | Input voltage at which positive current output is cut to zero.                                   |
| `l_battery_regen_cut_start` | `1000.0 V` | Input voltage at which regen current begins to ramp down (set very high to effectively disable). |
| `l_battery_regen_cut_end`   | `1100.0 V` | Input voltage at which regen current is cut to zero.                                             |

<Tip>
  Set `l_battery_cut_start` and `l_battery_cut_end` to match your battery chemistry's minimum cell voltage multiplied by cell count, to protect cells from deep discharge.
</Tip>

## Temperature limits

| Parameter                | Default                   | Description                                                                                      |
| ------------------------ | ------------------------- | ------------------------------------------------------------------------------------------------ |
| `l_temp_fet_start`       | `85.0 °C`                 | MOSFET temperature at which current begins to be reduced.                                        |
| `l_temp_fet_end`         | `100.0 °C`                | MOSFET temperature at which the motor is shut off (`FAULT_CODE_OVER_TEMP_FET`).                  |
| `l_temp_motor_start`     | `85.0 °C`                 | Motor temperature at which current begins to be reduced.                                         |
| `l_temp_motor_end`       | `100.0 °C`                | Motor temperature at which the motor is shut off (`FAULT_CODE_OVER_TEMP_MOTOR`).                 |
| `l_temp_accel_dec`       | `0.15`                    | Fraction by which temperature limits are reduced during acceleration to prevent thermal runaway. |
| `m_motor_temp_sens_type` | `TEMP_SENSOR_NTC_10K_25C` | Type of motor temperature sensor.                                                                |
| `m_ntc_motor_beta`       | `3380.0`                  | Beta coefficient for the NTC motor thermistor.                                                   |
| `m_ptc_motor_coeff`      | `0.61 %/K`                | Resistance change coefficient for PTC sensors.                                                   |

## RPM limits

| Parameter              | Default         | Description                                                            |
| ---------------------- | --------------- | ---------------------------------------------------------------------- |
| `l_max_erpm`           | `100,000 ERPM`  | Maximum electrical RPM (upper).                                        |
| `l_min_erpm`           | `-100,000 ERPM` | Minimum electrical RPM (lower).                                        |
| `l_erpm_start`         | `0.8`           | Fraction of `l_max_erpm` at which RPM-based current limiting begins.   |
| `l_max_erpm_fbrake`    | `300 ERPM`      | Maximum ERPM at which full braking is applied.                         |
| `l_max_erpm_fbrake_cc` | `1500 ERPM`     | Maximum ERPM at which full braking is applied under current control.   |
| `l_min_duty`           | `0.005`         | Minimum duty cycle.                                                    |
| `l_max_duty`           | `0.95`          | Maximum duty cycle.                                                    |
| `l_duty_start`         | `1.0`           | Duty cycle fraction at which current limiting begins (1.0 = disabled). |

## Motor parameters

These parameters describe the physical motor and are normally determined by running motor detection in VESC Tool.

| Parameter                | Default                       | Description                                                         |
| ------------------------ | ----------------------------- | ------------------------------------------------------------------- |
| `si_motor_poles`         | `14`                          | Number of motor poles (pole count, not pole pairs).                 |
| `si_gear_ratio`          | `3.0`                         | Drive gear ratio (motor revolutions per wheel revolution).          |
| `si_wheel_diameter`      | `0.083 m`                     | Wheel diameter in meters, used for speed and odometer calculations. |
| `si_battery_type`        | `BATTERY_TYPE_LIION_3_0__4_2` | Battery chemistry selection for display and BMS integration.        |
| `si_battery_cells`       | `3`                           | Number of cells in series.                                          |
| `si_battery_ah`          | `6.0 Ah`                      | Battery capacity in amp-hours.                                      |
| `si_motor_nl_current`    | `1.0 A`                       | Motor no-load current, used for efficiency calculations.            |
| `foc_motor_l`            | `7 µH`                        | Phase inductance (L). Set by motor detection.                       |
| `foc_motor_r`            | `15 mΩ`                       | Phase resistance (R). Set by motor detection.                       |
| `foc_motor_flux_linkage` | `0.00245 Wb`                  | Motor flux linkage (λ). Set by motor detection.                     |
| `foc_motor_ld_lq_diff`   | `0.0 H`                       | Difference between d-axis and q-axis inductance (saliency).         |

<Note>
  The default motor parameters are placeholders. Always run motor detection for accurate FOC operation.
</Note>

## FOC parameters

<AccordionGroup>
  <Accordion title="Current controller">
    | Parameter                  | Default                      | Description                                                  |
    | -------------------------- | ---------------------------- | ------------------------------------------------------------ |
    | `foc_current_kp`           | `0.03`                       | Proportional gain of the d/q axis current PI controller.     |
    | `foc_current_ki`           | `50.0`                       | Integral gain of the d/q axis current PI controller.         |
    | `foc_f_zv`                 | `25,000 Hz`                  | Zero-vector (switching) frequency for FOC.                   |
    | `foc_dt_us`                | `0.12 µs`                    | Dead-time compensation in microseconds.                      |
    | `foc_cc_decoupling`        | `FOC_CC_DECOUPLING_DISABLED` | Cross-coupling compensation mode for the current controller. |
    | `foc_sat_comp_mode`        | `SAT_COMP_DISABLED`          | Stator saturation compensation mode.                         |
    | `foc_sat_comp`             | `0.0`                        | Stator saturation compensation factor.                       |
    | `foc_current_filter_const` | `0.1`                        | Low-pass filter constant for displayed/logged currents.      |
    | `foc_overmod_factor`       | `1.0`                        | Overmodulation factor (>1.0 enables overmodulation).         |
  </Accordion>

  <Accordion title="Observer">
    | Parameter                | Default                              | Description                                                        |
    | ------------------------ | ------------------------------------ | ------------------------------------------------------------------ |
    | `foc_observer_type`      | `FOC_OBSERVER_MXLEMMING_LAMBDA_COMP` | Position observer algorithm.                                       |
    | `foc_observer_gain`      | `9×10⁷`                              | Observer feedback gain. A starting point is approximately 600 / L. |
    | `foc_observer_gain_slow` | `0.05`                               | Fraction of `foc_observer_gain` used at minimum duty cycle.        |
    | `foc_observer_offset`    | `-1.0`                               | Observer angle offset in timer update cycles.                      |
    | `foc_pll_kp`             | `2000.0`                             | PLL proportional gain used by the speed tracker.                   |
    | `foc_pll_ki`             | `30,000.0`                           | PLL integral gain used by the speed tracker.                       |
  </Accordion>

  <Accordion title="Sensor mode and open-loop">
    | Parameter                   | Default                      | Description                                                          |
    | --------------------------- | ---------------------------- | -------------------------------------------------------------------- |
    | `foc_sensor_mode`           | `FOC_SENSOR_MODE_SENSORLESS` | Sensor mode: sensorless, encoder, hall, HFI, or variants.            |
    | `foc_sl_erpm`               | `3500 ERPM`                  | ERPM above which only the observer is used (hybrid mode transition). |
    | `foc_sl_erpm_start`         | `2500 ERPM`                  | ERPM below which only sensored commutation is used (hybrid mode).    |
    | `foc_openloop_rpm`          | `1500 ERPM`                  | Target RPM during open-loop startup or index-finding.                |
    | `foc_openloop_rpm_low`      | `0.0`                        | Fraction of `foc_openloop_rpm` at minimum current.                   |
    | `foc_sl_openloop_hyst`      | `0.1 s`                      | Time below minimum RPM before open-loop is activated.                |
    | `foc_sl_openloop_time`      | `0.05 s`                     | Time to remain in open-loop after RPM ramp.                          |
    | `foc_sl_openloop_time_lock` | `0.0 s`                      | Time to lock rotor at start of open-loop sequence.                   |
    | `foc_sl_openloop_time_ramp` | `0.1 s`                      | Time to ramp up to open-loop speed.                                  |
  </Accordion>

  <Accordion title="Field weakening">
    | Parameter                 | Default | Description                                                                     |
    | ------------------------- | ------- | ------------------------------------------------------------------------------- |
    | `foc_fw_current_max`      | `0.0 A` | Maximum negative d-axis current for field weakening (0 = disabled).             |
    | `foc_fw_duty_start`       | `0.8`   | Duty cycle fraction at which field weakening begins.                            |
    | `foc_fw_ramp_time`        | `0.0 s` | Ramp time for field weakening current.                                          |
    | `foc_fw_q_current_factor` | `0.05`  | Fraction of field weakening current fed to the q-axis when target current is 0. |

    <Warning>
      Field weakening increases motor and FET stress. Start with `foc_fw_current_max` set to a small fraction of `l_current_max` and monitor temperatures carefully.
    </Warning>
  </Accordion>

  <Accordion title="HFI (High Frequency Injection)">
    | Parameter               | Default                   | Description                                                            |
    | ----------------------- | ------------------------- | ---------------------------------------------------------------------- |
    | `foc_hfi_voltage_start` | `20 V`                    | Injection voltage during ambiguity resolution at start.                |
    | `foc_hfi_voltage_run`   | `4 V`                     | Injection voltage during normal HFI tracking.                          |
    | `foc_hfi_voltage_max`   | `6 V`                     | Injection voltage at maximum current.                                  |
    | `foc_hfi_gain`          | `0.3`                     | Correction gain for HFI V2 mode.                                       |
    | `foc_hfi_max_err`       | `0.30 rad`                | Maximum HFI angle error before truncation (noise rejection).           |
    | `foc_hfi_hyst`          | `0.0`                     | Sense vector offset hysteresis.                                        |
    | `foc_sl_erpm_hfi`       | `3000 ERPM`               | ERPM above which the observer takes over from HFI.                     |
    | `foc_hfi_reset_erpm`    | `500 ERPM`                | ERPM below which the HFI state is reset.                               |
    | `foc_hfi_samples`       | `HFI_SAMPLES_16`          | Number of HFI injection samples per electrical revolution.             |
    | `foc_hfi_start_samples` | `5`                       | Number of samples taken at start for ambiguity resolution.             |
    | `foc_hfi_obs_ovr_sec`   | `0.001 s`                 | Duration to continue using the observer when entering HFI speed range. |
    | `foc_hfi_amb_mode`      | `FOC_AMB_MODE_SIX_VECTOR` | HFI ambiguity resolution mode.                                         |
    | `foc_hfi_amb_current`   | `60.0 A`                  | Current used during HFI ambiguity resolution.                          |
    | `foc_hfi_amb_tres`      | `15`                      | Ambiguity resolution threshold.                                        |
  </Accordion>

  <Accordion title="Phase filter">
    | Parameter                        | Default     | Description                                                      |
    | -------------------------------- | ----------- | ---------------------------------------------------------------- |
    | `foc_phase_filter_enable`        | `true`      | Enable hardware phase voltage filters when available.            |
    | `foc_phase_filter_disable_fault` | `true`      | Disable `FAULT_CODE_PHASE_FILTER` (fault suppressed by default). |
    | `foc_phase_filter_max_erpm`      | `4000 ERPM` | Use phase voltage filter only below this ERPM.                   |
  </Accordion>

  <Accordion title="Temperature compensation and MTPA">
    | Parameter                 | Default         | Description                                        |
    | ------------------------- | --------------- | -------------------------------------------------- |
    | `foc_temp_comp`           | `false`         | Enable motor resistance temperature compensation.  |
    | `foc_temp_comp_base_temp` | `25.0 °C`       | Reference temperature for resistance compensation. |
    | `foc_mtpa_mode`           | `MTPA_MODE_OFF` | Maximum torque per amp algorithm mode.             |
  </Accordion>
</AccordionGroup>

## Speed PID parameters

| Parameter             | Default               | Description                                                  |
| --------------------- | --------------------- | ------------------------------------------------------------ |
| `sp_pid_loop_rate`    | `PID_RATE_1000_HZ`    | PID loop execution rate (shared by speed and position PID).  |
| `s_pid_kp`            | `0.004`               | Speed PID proportional gain.                                 |
| `s_pid_ki`            | `0.004`               | Speed PID integral gain.                                     |
| `s_pid_kd`            | `0.0001`              | Speed PID derivative gain.                                   |
| `s_pid_kd_filter`     | `0.2`                 | Low-pass filter constant for the speed PID derivative term.  |
| `s_pid_min_erpm`      | `900 ERPM`            | Minimum ERPM for the speed PID (below this, output is zero). |
| `s_pid_allow_braking` | `true`                | Allow the speed PID to apply braking current.                |
| `s_pid_ramp_erpms_s`  | `25,000 ERPM/s`       | Speed setpoint ramp rate.                                    |
| `s_pid_speed_source`  | `S_PID_SPEED_SRC_PLL` | Speed source used by the PID controller.                     |

## Position PID parameters

| Parameter              | Default   | Description                                                    |
| ---------------------- | --------- | -------------------------------------------------------------- |
| `p_pid_kp`             | `0.025`   | Position PID proportional gain.                                |
| `p_pid_ki`             | `0.0`     | Position PID integral gain.                                    |
| `p_pid_kd`             | `0.0`     | Position PID derivative gain (error-based).                    |
| `p_pid_kd_proc`        | `0.00035` | Position PID derivative gain (process-variable-based).         |
| `p_pid_kd_filter`      | `0.2`     | Low-pass filter constant for the position PID derivative term. |
| `p_pid_ang_div`        | `1.0`     | Divide angle error by this value before the PID.               |
| `p_pid_gain_dec_angle` | `0.0`     | Reduce PID gains when error is below this angle.               |
| `p_pid_offset`         | `0.0 °`   | Angle offset added to the position setpoint.                   |

## Miscellaneous parameters

| Parameter                | Default                 | Description                                                         |
| ------------------------ | ----------------------- | ------------------------------------------------------------------- |
| `m_fault_stop_time_ms`   | `500 ms`                | Duration for which motor commands are ignored after a fault clears. |
| `m_duty_ramp_step`       | `0.02`                  | Maximum duty cycle ramp step per millisecond in duty control mode.  |
| `m_current_backoff_gain` | `0.5`                   | Gain of the current limiting backoff algorithm.                     |
| `m_encoder_counts`       | `8192`                  | Number of encoder counts per revolution.                            |
| `m_sensor_port_mode`     | `SENSOR_PORT_MODE_HALL` | Mode of the combined hall/encoder sensor port.                      |
| `m_invert_direction`     | `false`                 | Invert the motor rotation direction.                                |
| `m_drv8301_oc_mode`      | `DRV8301_OC_LIMIT`      | Gate driver over-current protection mode.                           |
| `m_drv8301_oc_adj`       | `16`                    | Gate driver over-current protection threshold (0–31).               |
| `m_bldc_f_sw_min`        | `3,000 Hz`              | Minimum switching frequency in BLDC mode.                           |
| `m_bldc_f_sw_max`        | `35,000 Hz`             | Maximum switching frequency in BLDC mode.                           |
| `m_dc_f_sw`              | `25,000 Hz`             | Fixed switching frequency in DC motor mode.                         |
| `m_out_aux_mode`         | `OUT_AUX_MODE_OFF`      | Auxiliary output pin behavior.                                      |
| `m_hall_extra_samples`   | `3`                     | Extra ADC samples averaged when reading hall sensors.               |
| `m_batt_filter_const`    | `45`                    | Battery voltage display filter time constant.                       |