Using Pulse Width Modulation (PWM) for Brushless DC Motor (BLDC) Speed Control

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Using Pulse Width Modulation (PWM) for Brushless DC Motor (BLDC) Speed Control
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Duration：10 minutes and 22 seconds
Date：2020/12/20

Uploader：抛砖引玉

Introduction

keywords： motor control BLDC MATLAB

Watch this video series to learn about brushless DC motor control. You will learn about the inner workings of BLDC and six-step commutation (trapezoidal control). The video will cover some examples that will show how to simulate a BLDC to study its back EMF shape and design a speed controller.

Learn the basics of brushless DC motors (BLDC). Brushless DC motors have many advantages over brushed DC motors. They have high efficiency and low maintenance costs, and have been widely used in household appliances, robotics and the automotive industry.

-The inner workings of a BLDC
-How to simulate a BLDC in Simulink® using Simscape Electrical™ and study the shape of its back-EMF voltage
-How to control a BLDC using six-step commutation (ladder control)
-How about a BLDC and a permanent magnet synchronous motor (PMSM) Controlled by trapezoidal and magnetic field orientations respectively

In this video, you will learn how to design a motor control algorithm for controlling the speed of a BLDC motor. You will learn how the different components of the system work, such as commutation logic and three-phase inverters. We will also discuss why we observe fluctuations in the speed and torque response of BLDC motors and give you a visual understanding of the concept of inductive flyback.

This video discusses what PWM (Pulse Width Modulation) is, and two architectures for using PWM control for BLDC motor speed control. PWM is a square wave signal that repeats itself at a certain frequency. Each PWM period is called a period, and the percentage of time the PWM signal is on during a given period determines the duty cycle. Using PWM we can adjust a constant DC voltage to different voltage levels. This helps us control the motor at variable speed. This video demonstrates two common architectures for PWM control. In the first one, we use a buck converter and a PWM generator to step down the DC supply voltage to a three-phase inverter. In the second one, we discussed a different architecture where PWM control is used to directly modulate the three-phase voltage.

Field-oriented control (FOC) is a technology used to control various motor types, including permanent magnet synchronous motors (PMSM). FOC uses Clarke and Park transforms to convert three-phase sinusoidal currents into DC and quadrature currents. You will learn how to control DC and quadrature currents so that the stator magnetic field direction is orthogonal to the rotor field direction, thereby maximizing torque production.

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