AVR447: Sinusoidal driving of three-phase permanent magnet motor using ATmega48/88/168

Features

•Three-phase sine waves

-192 steps per electrical revolution

-8-bit amplitude resolution

•Software dead-time generation

•Controlled by hall-sensors

•Speed control through run-time scaling of sine wave amplitude

-Speed reference from analog input

•Automatically synchronizes to a running motor at startup

•Safe startup using block-commutation the first commutation steps

•Direction controlled by digital input

•Safe stop and direction change procedure

-Active braking or coasting during stopping

•Advance commutation angle adjustable at run-time

•Reverse rotation signal output

•Tacho output signal

1 Introduction

This application note describes the implementation of sinusoidal driving for threephase brushless DC motors with hall sensors.

The implementation can easily be modified to use other driving waveforms such as sine wave with third harmonic injected.

Figure 1-2. Sine wave driving of brushless DC motor with hall sensors.

8-bit Microcontrollers

Application Note

8010A-AVR-06/06