AN1858: Sensorless Brushless dc Motor Using the MC68HC908MR32 Embedded Motion Control Development System

Overview Motorola's MC68HC908MR32 (MR32) microcontroller (MCU) is specifically designed for motor control applications. The MR32 is suitable for ac induction motors as well as brushless dc (BLDC) motors. The pulse-width modulator motor control (PWMMC) module can be configured to control brushless dc (BLDC) motors using several different PWM strategies. BLDC motors are being designed into many applications that require fractional horsepower, highly efficient, variable speed motors. Brushless dc motors have several advantages over other motor types. For instance: • Because BLDC motors do not have brushes to wear out, they have a longer life and greater reliability than normal brushed dc motors. • BLDC motors offer performance similar to dc motors with a high starting torque and a high no-load speed.