Are you curious about why a BLDC motor without carbon brushes can rotate continuously and stably? In the fields of smart home and new energy vehicles, BLDC motors are favored for their high efficiency and energy saving, and brushless commutation is the “heart” of BLDC motors. This article will unveil the mystery of this technology for you and help you quickly master the core principles.
The core mechanism and principle of brushless commutation
Customers often wonder how BLDC motors can achieve commutation without carbon brushes to conduct current? Traditional brushed motors rely on mechanical contact between carbon brushes and commutators to switch the direction of current, while BLDC motors use electronic commutation to solve the problem of carbon brush wear from the root. The BLDC motor consists of a stator winding and a permanent magnet rotor. Its core is to accurately control the stator winding current by detecting the rotor position. Take the Hall sensor as an example. It is like the “eye” of the motor, monitoring the rotor pole position in real time. When the rotor rotates, the signal output by the Hall sensor changes. After receiving the signal, the controller immediately adjusts the current direction of the stator winding so that the stator magnetic field rotates synchronously with the rotor, thereby achieving brushless commutation. If a sensorless solution is adopted, the rotor position information is indirectly obtained by detecting the back electromotive force. Although the cost is lower, the control difficulty is relatively high.
Key technical paths to achieve brushless commutation
To achieve stable brushless commutation, it is necessary to start from both hardware and software. In terms of hardware, choosing a suitable position sensor (Hall sensor or encoder) is the basis, and its accuracy directly affects the commutation accuracy. At the same time, a high-performance motor controller is essential, which must have the ability to quickly process signals and accurately control current. At the software level, advanced control algorithms are crucial. For example, the field-oriented control (FOC) algorithm decomposes the three-phase current into independent torque current and excitation current through coordinate transformation, realizes precise control of the motor torque, effectively reduces torque fluctuations, and improves running stability. In addition, the optimized commutation logic can reduce current shock and extend the life of the motor.
The value and implementation guide of brushless commutation technology
Brushless commutation technology gives BLDC motors significant advantages, not only improving motor efficiency and reliability, but also reducing maintenance costs, and is widely used in many fields. In new energy vehicles, precise brushless commutation allows the motor to drive the vehicle efficiently; in smart home devices, it brings a quiet and energy-saving experience. To implement this technology, it can be carried out in three steps:
（1）Clarify the application scenario requirements and select the appropriate motor model and sensor accordingly;
（2）Develop or select an adaptive controller and control algorithm to ensure accurate commutation;
（3）Perform comprehensive testing and optimization, adjust parameters according to actual operating data, and achieve optimal performance.
Mastering the principles and implementation methods of BLDC motor brushless commutation can enable us to better select and use related products. Whether you are a technical practitioner or an enthusiast, you may wish to study this technology in depth. If you have more questions or practical needs, please share and communicate, and start a wonderful journey to explore BLDC motors.