Yi L.,Industrial Engineering Engineering Science
Electronics World | Year: 2013
A control solution that can be used with any brushless DC microcontroller (BLDC) with the minimum required hardware peripherals is discussed. BLDC motors have Hall sensors embedded in their stators. The Hall sensors generate a high or low signal when the N or S rotor magnetic pole passes nearby. Based on the sequence of signals coming from the Hall sensors the designer defines the commutation sequence. There are various modulation methods for controlling inverter drives, upper modulation, lower modulation, rotating modulation, or balanced modulation, but upper modulation is most suited to implement on a low-cost microcontroller. order to control the three phase bridge using the upper modulation technique, the microcontroller must be able to generate three PWM signals and it must have a timer or a PWM module capable of generating them. An important feature that must be implemented in every embedded for motor control system is overcurrent protection. This requires an analog-to-digital converter or an analog comparator must be used.