Motor Control Skill

Overview

This skill provides motor control algorithm implementation and driver development expertise for embedded systems controlling DC, BLDC, stepper, and AC induction motors.

Capabilities

PWM Generation

• Center-aligned PWM configuration
• Dead-time insertion
• Complementary output setup
• PWM frequency selection
• Duty cycle modulation
• SVPWM (Space Vector PWM)

Control Algorithms

• FOC (Field-Oriented Control)
• Scalar V/f control
• Six-step commutation
• Sinusoidal commutation
• DTC (Direct Torque Control)
• Model predictive control

Position/Speed Feedback

• Encoder interface (quadrature)
• Hall sensor configuration
• Resolver interface
• Sensorless algorithms
• Back-EMF zero-crossing
• Observer-based estimation

Current Sensing

• Shunt resistor configuration
• Current amplifier setup
• ADC synchronization with PWM
• Oversampling strategies
• DC offset compensation
• Phase reconstruction

Control Loops

• Current loop (torque control)
• Speed loop (velocity control)
• Position loop (servo control)
• Anti-windup strategies
• Feed-forward compensation
• Gain tuning methods

Motor Identification

• Parameter measurement
• Auto-tuning procedures
• Resistance/inductance measurement
• Back-EMF constant
• Inertia estimation

Protection Features

• Overcurrent protection
• Overvoltage protection
• Overtemperature monitoring
• Stall detection
• Safe torque off (STO)

Target Processes

• device-driver-development.js - Motor driver implementation
• real-time-architecture-design.js - Real-time control design
• isr-design.js - Control loop ISR design

Dependencies

• Motor control libraries (ST MC SDK, TI MotorWare)
• DSP libraries for fixed-point math
• Encoder/Hall sensor hardware

Usage Context

This skill is invoked when tasks require:

• Motor driver development
• FOC algorithm implementation
• Position/speed control
• Motor parameter tuning
• Protection circuit design

Motor Types Supported

| Type | Control Method | Feedback | |------|---------------|----------| | Brushed DC | PWM duty cycle | Encoder optional | | BLDC | Six-step, FOC | Hall, encoder, sensorless | | PMSM | FOC | Encoder, resolver, sensorless | | Stepper | Step/direction, microstepping | Open-loop, encoder | | AC Induction | V/f, FOC | Encoder, sensorless |

FOC Implementation Example

c
typedef struct {
    float i_alpha, i_beta;    // Clarke transform output
    float i_d, i_q;           // Park transform output
    float v_d, v_q;           // Voltage commands
    float v_alpha, v_beta;    // Inverse Park output
    float theta;              // Rotor angle
    float speed;              // Rotor speed
} foc_state_t;

void foc_current_loop(foc_state_t* state, float i_a, float i_b, float i_c) {
    // Clarke transform
    clarke_transform(i_a, i_b, i_c, &state->i_alpha, &state->i_beta);

    // Park transform
    park_transform(state->i_alpha, state->i_beta, state->theta,
                   &state->i_d, &state->i_q);

    // PI controllers
    state->v_d = pi_controller(&pid_d, state->i_d_ref - state->i_d);
    state->v_q = pi_controller(&pid_q, state->i_q_ref - state->i_q);

    // Inverse Park
    inv_park_transform(state->v_d, state->v_q, state->theta,
                       &state->v_alpha, &state->v_beta);

    // SVPWM
    svpwm_generate(state->v_alpha, state->v_beta, pwm_duties);
}

Configuration

yaml
motor_control:
  motor_type: bldc | pmsm | stepper | induction
  control_method: foc | six_step | vf | step_dir
  pwm_frequency: 20000  # Hz
  current_loop_rate: 20000  # Hz
  speed_loop_rate: 1000  # Hz
  feedback: encoder | hall | sensorless