Field-Oriented Control (FOC) on STM32 From Scratch

This project demonstrates a complete, low-level implementation of Field-Oriented Control (FOC) for controlling a BLDC motor using an STM32F4 microcontroller, without relying on high-level motor control libraries.

Built using PlatformIO, STM32 HAL/LL drivers, and FreeRTOS, this project is designed for learning and practical experimentation in precision motor control.

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Features Implemented

• Clarke & Park Transforms
• Position feedback via AS5047 encoder
• Phase current sampling via ADC
• SVPWM (Space Vector PWM) generation
• Torque Control
• Speed Control
• Position Control
• Encoder auto callibration
• Self-Commissioning for PI Gain current controller auto tuning
• Sensorless mode using Sliding Mode Observer (SMO) & High Frequency Injection (HFI)
• USB CDC interface for real-time tuning and monitoring
• Save configuration to flash memory
• Interrupt-driven timing and FreeRTOS tasking

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Development Tools

• PlatformIO
• STM32CubeMX
• STM32Cube HAL & LL Drivers
• FreeRTOS (via PlatformIO package)
• VS Code + Serial Monitor for debugging
• Altium Designer (for Hardware) you can see in STM32-FOC-hardware.zip
• ACTUATOR CONTROL APP in controller_app.zip

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Simple Command Line Interface (CLI)

• change control mode: mode <mode>
<mode>:
  0 -> torque/current control
  1 -> speed control
  2 -> position control
• change set point: sp <value>
• run self commissioning: calib
• read motor parameters: motor_param
• read all PID parameters: pid <control>
<control>:
  id -> direct current control
  iq -> quadrature current control
  speed -> speed control
  position -> position control
• read PID specific parameter: pid <control> <param>
<param>:
  kp -> proportional gain
  ki -> integral gain
  kd -> derivative gain
  deadband -> error deadband (min error)
  max -> max output
• write PID parameter: pid <control> <param> <value>
• save changes to flash memory: save
• reset settingst: set_default
• add/remove plot variable: plot <action> <param>
<action>:
  add -> add parameter to plot
  rm -> remove parameter from plot
  <param>:
  ia, ib, ic → phase current (A)
  i_alpha, i_beta → alpha / beta current (A)
  id, iq → d–q current (A)
  va, vb, vc → phase voltage (V)
  v_alpha, v_beta → alpha / beta voltage (V)
  vd, vq → d–q voltage (V)
  v_bus → DC bus voltage (V)
  rpm → motor speed (RPM)
  e_rad → electrical angle (radian)
  m_deg → mechanical angle (degree)

UPDATE LOG

08-02-2026

• Change CLI format
• Integrate sensorless and sensored in one function and struct

03-02-2026

• Add Initial position detection with polarity judgement

20-01-2026

• Update HFI using single-bin Sliding DFT

26-11-2025

• Add sensorless mode using High Frequency Injection (HFI)
• Hysteresis switching between SMO and HFI

11-11-2025

• Add sensorless mode using Sliding Mode Observer (SMO)
• Dynamic max output PI controller Id Iq based on Vbus
• Save Rs, Ld, Lq to flash memory
• Move parse CLI code to controller_app

30-10-2025

• change algorithm to estimate resistance using constant voltage (vd)

15-10-2025

• self commissioning, auto calculate Motor Resistance and Inductance (Rs, Ld, and Lq)
• Auto Calculate PI Gain Current Control loop using R, L, and Bandwidth
• Setting bandwidth using CLI set_bandwidth=(bandwidth in Hz)
• move custom library code to lib folder

6-10-2025

• CAN bus
• Haptic control demo
• Setting Error Deadband and Max out PID Controler using CLI

16-9-2025

• Update audio mode

20-8-2025

• ADC injected simultaneous mode to read currents and DC voltage faster
• Add command to change title, legends, and erase graph in serial plotter

9-8-2025

• Add eccentricity calibration for magnetic encoder
• CLI for auto calibration
• Change PID manual tuning settings
• Save configuration to flash memory
• Default config

29-7-2025

• Add parity check for AS5047P

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