Motor Control

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

FOC Implementation Example

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

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