Ebook

Understanding BLDC Motor Control Algorithms

Chapter 2

Attaching a Controller and Building a Simulation Model of the Motor

Currently, the inverter is fed a constant DC voltage, which results in constant speed as discussed before. We can adjust this voltage by closing the loop with a suitable controller, such as a PID controller as shown in the block diagram below. Based on the difference between the desired and measured speed, the controller will adjust the voltage to bring the motor speed close to the desired value. Note that the blocks shown in light blue represent the control algorithm, while the components of the physical system are highlighted in light gray.

Illustration showing the closed-loop motor control diagram, where the B L D C motor is controlled via a P I D controller.

The closed-loop BLDC speed control algorithm can be implemented in a simulation environment as shown in the Simulink® block diagram below. The matching block labels show how the different components of the control algorithm map to the subsystems in the Simulink model.

A screenshot of the implementation of the closed-loop B L D C motor control algorithm with Simulink.

In this simulation, it is assumed that the voltage can be changed in an ideal manner to demonstrate motor operation, but in reality, pulse-width modulation (PWM) is required to do so.

Read more about implementing motor control algorithms using space vector modulation