Principle and Operation of the BLDC Motor/Controller Pair*
Brushless DC motors, or BLDC motors, are found everywhere in our modern daily lives: drones, electric bikes, smart fans, domestic robots... Their popularity is no accident: these motors combine efficiency, longevity, and low maintenance.
To understand why, it's essential to look at their internal architecture and the crucial role of the accompanying motor controller.
The Internal Architecture of a BLDC Motor
A BLDC motor mainly consists of two elements:
The stator, made up of coils, which produces the magnetic field.
The rotor, equipped with permanent magnets, which rotates under the influence of this field.
When current passes through the stator coils, it generates a rotating magnetic field. The poles of the rotor are then attracted or repelled, causing mechanical rotation.
Unlike traditional DC motors, commutation is not handled by mechanical brushes. Here, it is electronically managed by the controller. This lack of contact reduces wear, improves efficiency, and allows for much quieter operation.
The Importance of the Motor Controller
If the motor transforms electrical energy into motion, the controller is the brain of the system. It manages electronic commutation by sending current to the correct phases of the stator according to the exact position of the rotor.
The quality of the controller directly impacts:
The performance of the motor
The smoothness of rotation
The lifespan of the system
Control Modes
BLDC controllers can operate in different modes depending on the application's needs:
Speed control: Maintains a constant speed despite load variations. Ideal for fans, pumps, or robots requiring fine regulation.
Torque control: Prioritises rotational force, perfect for powerful starts or high-load applications like power tools or industrial systems.
Control Parameters
The motor's behaviour can be refined through several controller settings:
Supply voltage: The higher it is, the faster the speed, but beware of overheating.
Switching frequency: A high frequency makes the motor more responsive and smoother, at the cost of additional losses.
Current profile: it allows for optimising torque according to speed and load, for operation suited to each application.
Advanced Functions
Modern controllers often integrate features for safety and performance:
Protection against overloads and short circuits
Thermal regulation to prevent overheating
Position control (servo mode), used in drones, robots, or machine tools for precise positioning
Conclusion
The BLDC motor/controller pair is a high-performance and configurable electromechanical system. The motor transforms electricity into motion, while the controller optimises this motion in terms of speed, torque, and precision.
A good coupling between motor and controller ensures maximum efficiency, reliability, and longevity, which explains why these systems have become indispensable in modern technologies.
*: The technical information presented in this article is provided for informational purposes only. It does not replace the official manuals of the manufacturers. Before any installation, handling, or use, please consult the product documentation and follow the safety instructions. Torque.works cannot be held responsible for inappropriate use or incorrect interpretation of the information provided.