Motor Inductance: Motor inductance is the resistance to changes in current in the motor. The time constants involved are typically faster than human perception. Changing inductance is crucial for control stability and rotor angle estimation.

Purpose:

• Setting higher inductance increases current gain, allowing the controller to correct current errors more aggressively.

• Used in the observer to estimate rotor position, affecting angle lead at high speeds and currents.

• Raising Motor Inductance: Increases current gain, causing the controller to output more voltage to correct current errors more aggressively Leads to a larger angle estimation at high speeds and currents in the observer.

• Lowering Motor Inductance: Reduces current gain, resulting in less aggressive correction of current errors. Decreases the angle estimation in the observer at high speeds and currents.

Motor Resistance: Motor resistance refers to the resistance to steady-state current flow, causing most of the motor heat (i^2*R).

Purpose:

• Primarily used in VESC for similar purposes as resistance.

• Sets Ki, dealing with steady-state error in the current controller for stability.

• Affects observer behavior at low speeds, with higher resistance causing lag in flux change estimation.

• Raising Motor Resistance: Increases Ki, affecting the steady-state error correction in the current controller. Affects observer behavior at low speeds, causing more lag in flux change estimation.

• Lowering Motor Resistance: Decreases Ki, impacting the steady-state error correction in the current controller.

  Affects observer behavior at low speeds, causing less lag in flux change estimation.

Current KP:

Kp is the Proportional Gain, a tuning factor in control systems.

• Cause: It decides how the system reacts to current errors, which are the differences between desired and actual values.

• Purpose: Kp adjusts immediate responses to deviations and influences the strength of corrective actions.

• Raising Current KP: Increases the proportional contribution to the control action.

  • Consequences:
    • Faster response to immediate errors.
    • Quicker correction of deviations from the desired state.
    • May lead to overshooting or instability if set too high.

• Lowering Current KP: Reduces the proportional contribution to the control action.

  • Consequences:
    • Slower response to immediate errors.
    • Slower correction of deviations from the desired state.
    • May result in a more stable but potentially sluggish system response.

Current KI:

Ki represents Integral Gain, a tuning parameter in control systems.

• Cause: It addresses steady-state errors, accumulating corrections over time for persistent deviations.

• Purpose: Ki ensures the elimination of persistent errors by responding to accumulated or integral errors.

• Raising Current KI: Increases the integral contribution to the control action.

  • Consequences:
    • Enhanced ability to eliminate persistent or steady-state errors.
    • Improved long-term accuracy.
    • Risk of instability or overshooting if set too high.

• Lowering Current KI: Reduces the integral contribution to the control action.

  • Consequences:
    • Reduced ability to eliminate persistent errors over time.
    • Slower correction of steady-state errors.
    • The system may be more responsive but might struggle with long-term accuracy.

Observer Gain: The observer's role is to monitor the passage of magnets across the coils, generating a roughly sinusoidal signal. To the microcontroller (MCU), this signal is represented as numbers, and due to factors like measurement error and quantization, it gradually drifts away from being a sinusoid around zero. The observer gain comes into play by pulling this signal back towards zero.

It’s Worth Noting: mxlemming and Ortega differ in how they correct signal drift. Ortega uses an elastic band that adjusts the pull towards zero, while mxlemming sets a fixed limit, acting like a rigid wall.

• Raising Observer Gain:
  • Results in a more aggressive correction towards zero.
  • This may lead to oscillations and undesirable behavior.
• Lowering Observer Gain:
  • Causes a less forceful correction toward zero.
  • This may result in the signal drifting away from zero, leading to the generation of inaccurate or "garbage" data.

Motor Inductance Difference: Motor Inductance Difference refers to the difference in inductance between the two phases of an electric motor. This happens because of manufacturing differences or uneven motor structure. In electric motor control, especially with Field-Oriented Control (FOC), Motor Inductance Difference is important. The FOC controller needs precise inductance information to control the current in the motor. If there's a big difference in inductance between phases, it can affect how well the FOC algorithm works.

• Cause: Primarily caused by the shape of magnets and their interaction with metal. In hub motors, it's influenced by magnet saturation in the stator.
• Usage in VESC: Limited use in VESC control, utilized in MTPA and as a correction factor in the observer inductance.

Motor Inductance Difference:

• Torque Impact: Tweaking this parameter can affect how much torque the motor produces, especially under specific conditions.
• High-Frequency Effects: Adjustments can be used for High-Frequency Injection (HFI), influencing certain motor behaviors.
• Strategy Influence: The parameter's changes matter more in specific strategies like MTPA, affecting how efficiently torque is produced per unit of current.
• System Performance: Overall, modifying the Motor Inductance Difference can subtly shape how well the motor control system performs. Precise tuning is key to achieving the desired effects without sacrificing stability or efficiency.

Motor Flux Linkage: Analogous to the inverse of kV, representing the area under the sin wave of a free-spinning motor.

• Cause: Motor Flux Linkage is the result of the area under the sine wave in a freely spinning motor, reflecting the amount of voltage multiplied by time per electrical revolution.
• Purpose: It plays a crucial role in observers within the control system, acting like the width of a lane for them to operate. The parameter's purpose is to provide space for observers to work effectively.
• Impact: Having the parameter too high may hinder the observer's ability to control estimated parameters while having it too low limits the parameters' movement space. Calibration is essential for optimal system performance.

Motor Flux Linkage:

• Impact on Observers: Increasing the Motor Flux Linkage parameter could potentially limit the observer's ability to effectively control estimated parameters. On the other hand, decreasing the parameter might restrict the movement space for these parameters within the system.
• System Performance: Proper adjustment is crucial for maintaining a balance. A well-calibrated Motor Flux Linkage parameter ensures that observers can operate optimally, contributing to efficient and stable system performance.
• No Substitute: Unlike some other parameters that might tolerate variations, there is no substitute for having the correct Motor Flux Linkage parameter. Precise adjustment is necessary for the system to function at its best.