Features

• Controls max 3 DC motors
• Current up to 4A/motor
• Supply voltage up to 46V
• Current sensing
• PWM control
• Single sided PCB
• 15 pin Control Unit compatible header

After examining BLDC controllers available on the net (mostly for RC airplanes), I decided to design and build my own controller for robots.

Requirements

• Sensorless
• Max voltage: 12V
• Max current: 10A
• I²C for control
• RS232 (5V) for diagnostic and configuration
• No SMD parts
• Minimum additional elements
• ISP connector for programming

Controller is based on Atmel ATmega8 chip with limited number of external components. Preliminary design is finished.

Introduction

A brushless DC motor is electric engine where the stator is a classic 3 phase stator and the rotor has surface mounted permanent magnets. It is equivalent to a reversed DC commutator motor, in which the magnet rotates while the conductors remain stationary. BLDC motor has no commutator and brushes, it requires electronic control for operation. They often have external position sensors used by control unit, but sensorless control is also possible.