Three-phase BLDC motor control involves the coordinated switching of three sets of stator windings to create a rotating magnetic field that interacts with the rotor’s permanent magnets. The entire process is controlled by a BLDC motor driver or controller, which manages commutation, speed regulation, and torque output.

The foundation of 3-phase BLDC motor control is the commutation sequence. Most BLDC motors use six-step (120-degree) commutation. In each electrical cycle, the controller energizes two phases while the third remains floating. This creates a rotating electromagnetic field that pulls the rotor forward. Proper commutation depends on the precise detection of rotor position, which is commonly achieved using Hall sensors.

PWM (Pulse Width Modulation) plays a key role in speed control. By adjusting the duty cycle applied to the active phases, the controller varies the average voltage delivered to the motor, thus controlling speed while maintaining good torque performance. Higher PWM duty cycles produce faster speeds, while lower duty cycles reduce speed proportionally.

Current sensing is another essential element. It protects the motor from overcurrent and enables advanced control strategies. Many controllers include shunt resistors or Hall-effect current sensors to monitor real-time current flow. This feedback allows the system to implement current limiting, torque regulation, and soft-start features.

For sensorless control, the driver relies on back-EMF generated in the floating phase. When the rotor moves, the back-EMF zero-crossing point indicates the rotor’s electrical position. This technique eliminates the need for Hall sensors and is ideal for cost-sensitive applications, though it performs less effectively at very low speeds.

Some advanced systems use Field-Oriented Control (FOC) or sinusoidal control for smoother operation, lower noise, and higher efficiency. Although traditionally associated with PMSM motors, FOC is increasingly applied in high-end BLDC motor controllers.

Applications of 3-phase BLDC motor control include industrial drives, robotics, electric scooters, drones, pumps, and air-conditioner compressors. With the global shift toward energy-efficient technologies, mastering BLDC control fundamentals is critical for engineers developing modern motion systems.