文档介绍：AVR447: Sinusoidal driving of three-phase
permanent motor using
ATmega48/88/168
8-bit
Microcontrollers
Features
• Three-phase sine waves
- 192 steps per electrical revolution Application Note
- 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 mutation the mutation steps
• Direction controlled by digital input
• Safe stop and direction change procedure
- Active braking or coasting during stopping
• mutation angle adjustable at run-time
• Reverse rotation signal output
• Tacho output signal
1 Introduction
This application note describes the implementation of sinusoidal driving for three-
phase 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.
8010A-AVR-06/06
2 Theory of operation
In most of the literature, permanent motors are divided into two categories
based on the shape of the back-EMF (voltage induced in the coils when the motor is
spinning). The back-EMF can either be trapezoidal or sinusoidal in shape. Although
the terminology is not consistent throughout the literature, the majority seems to
agree that a brushless DC motor (BLDC) has trapezoidal back-EMF, while a
permanent synchronous motor (PMSM) has sinusoidal back-EMF. Both
BLDC and PMSM motors can be driven by sinusoidal currents, so there will not be
made any distinction between them throughout this application note. Instead, they will
both be referred to as a permanent motor, or PMM.
3 Implementation on an AVR®
This application note describes how to drive a three-phase PMM with sinusoidal
currents. The code examp