Brushless DC Motors – Part I: Construction and Operating Principles. Electrical equipment often has at least one motor used to rotate or displace an object from its initial position. There are a variety of motor types available in the market, including induction motors, servomotors, DC motors (brushed and brushless), etc. Depending upon the application requirements, a particular motor can be selected. However, a current trend is that most new designs are moving towards Brushless DC motors, popularly known as BLDC motors. This article will concentrate on the following aspects of BLDC motor design: Construction of the BLDC motor. Operation of the BLDC motor. Torque and Efficiency requirements. Comparison with Induction and Brushed DC motors. Selection criteria for a BLDC motor. Motor control – Speed, Position and Torque, to be covered in Part II of this article. Construction BLDC motors have many similarities to AC induction motors and brushed DC motors in terms of construction and working principles respectively. Like all other motors, BLDC motors also have a rotor and a stator. Windings in a stator can be arranged in two patterns; i. The major difference between the two patterns is that the Y pattern gives high torque at low RPM and the . A slotless core has lower inductance, thus it can run at very high speeds. The main disadvantage of a slotless core is higher cost because it requires more winding to compensate for the larger air gap. An improper selection may lead to multiple problems during production, resulting in market delays and increased design costs. Rotor The rotor of a typical BLDC motor is made out of permanent magnets. Depending upon the application requirements, the number of poles in the rotor may vary. Increasing the number of poles does give better torque but at the cost of reducing the maximum possible speed. Working Principles and Operation The underlying principles for the working of a BLDC motor are the same as for a brushed DC motor; i. In case of a brushed DC motor, feedback is implemented using a mechanical commutator and brushes. With a in BLDC motor, it is achieved using multiple feedback sensors. If the direction of the magnetic field is reversed, the voltage developed will reverse as well. For Hall- effect sensors used in BLDC motors, whenever rotor magnetic poles (N or S) pass near the hall sensor, they generate a HIGH or LOW level signal, which can be used to determine the position of the shaft. In a commutation system – one that is based on the position of the motor identified using feedback sensors – two of the three electrical windings are energized at a time as shown in figure 4. In figure 4 (A), the GREEN winding labeled “0. NORTH pole and the BLUE winding labeled as “0. SOUTH pole. Because of this excitation, the SOUTH pole of the rotor aligns with the GREEN winding and the NORTH pole aligns with the RED winding labeled “1. In order to move the rotor, the “RED” and “BLUE” windings are energized in the direction shown in figure 4(B). This causes the RED winding to become the NORTH pole and the BLUE winding to become the SOUTH pole. This shifting of the magnetic field in the stator produces torque because of the development of repulsion (Red winding – NORTH- NORTH alignment) and attraction forces (BLUE winding – NORTH- SOUTH alignment), which moves the rotor in the clockwise direction. 3-Phase BLDC Motor Control with Sensorless Back EMF Zero Crossing Detection Using 56F80x Design of 3-Phase BLDC Motor Control. The Brushless DC motor (BLDC motor) is also referred to as an electronically commuted motor. MODELING AND CONTROL OF A BRUSHLESS DC MOTOR A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE. AVR493: Sensorless Commutation of Brushless DC Motor (BLDC) using AT90PWM3 and ATAVRMC100 1. Introduction This application note describes how to implement a sensorless commutation of BLDC motors with the ATAVRMC100. Direct Back EMF Detection Method for Sensorless Brushless DC (BLDC) Motor Drives Jianwen Shao ABSTRACT Brushlesss dc (BLDC) motors and their drives are penetrating the market of home appliances, HVAC industry, and automotive. Brushless AC Motor Commutation Sinusoidal Commutation with a PC based Motion Controller Application Note AN1004 Precision MicroControl Corporation 2075-N Corte del Nogal Carlsbad, CA 92009-1415 USA Tel: (760) 930-0101 Fax. Brushless Motors: HOW DO THEY WORK? Brushless DC motors are simple enough: magnets attached to a shaft are. Take a brushless motor apart; you’ll see a number of loops of shiny copper wire running parallel to the motor shaft. Popular Motor Designs The DC motor, brushless DC, and AC induction motor are the popular motor designs used in today's industrial applications. Each of these motor types has its own unique characteristics, but they all operate. How a brushless motor works ( animation) iulian207. Subscribe Subscribed Unsubscribe. Want to watch this again later? Standard YouTube License; Loading. Design of 3-Phase BLDC Motor for Electric Vehicle Application by Using Finite Element Simulation.
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