Custom BLDC Motor Controller

Overview

This project delivered an end-to-end BLDC motor controller combining a 2-layer control PCB, STM32G473 motor-control MCU, 3-phase MOSFET bridge, QSPI flash, touchscreen interface, and FreeRTOS-based firmware.

Highlights

• Closed-loop PID speed control
• Touchscreen and physical-button interface
• Hardware-level brake, STOP, and over-speed safety
• Validated against a laser tachometer reference

Challenges

• Stabilize PID speed control against noisy frequency feedback.
• Synchronize motor, display, and button tasks without race conditions.
• Design a clean 3-phase MOSFET driver with gate-drive, switching-noise, and isolation considerations.
• Boot firmware from external QSPI flash using a custom External Loader.

Solutions

• Integrated MCU, driver, power, display, and inputs on one compact 2-layer PCB.
• Separated motor, screen, and button workflows with FreeRTOS tasks protected by mutexes and semaphores.
• Used TIM2 input capture, low-pass speed estimation, bounded PID output, and anti-windup control.
• Cross-checked commanded RPM, on-screen RPM, and non-contact laser tachometer measurements.

Features

• Manual hold, auto ramp with countdown, recalibration, STOP, and over-speed brake modes.
• ST7796 LCD with FT6336 capacitive touch.
• 24V/12V power input with integrated motor-control electronics.

Key Results

• Working prototype built and tested on real hardware.
• Closed-loop accuracy validated against calibrated reference measurements.
• Hardware, driver electronics, and firmware delivered under one roof.