[Technical Tips] Why is motor FOC control becoming more and more popular?-EEWORLD

Collect

FOC control algorithm

Why is FOC becoming more and more popular?

What is FOC?

FOC (Field-Oriented Control), also known as vector frequency conversion, is currently the best choice for efficient control of brushless DC motors (BLDC) and permanent magnet synchronous motors (PMSM).

FOC precisely controls the size and direction of the magnetic field, making the motor torque stable, low noise, high efficiency, and high-speed dynamic response. It has gradually replaced traditional control methods in many applications and has attracted much attention in the motion control industry.

The principle of FOC

FOC control first needs to obtain the position of the motor rotor, motor speed, current and other information as feedback input. It is necessary to collect the motor phase current and perform a series of mathematical transformations and estimation algorithms on it to obtain the decoupled and easy-to-use control feedback.

The controller dynamically adjusts according to the error between the feedback value and the target value, and finally outputs a three-phase sinusoidal wave to drive the motor to rotate.

FOC typical control block diagram

Sensored FOC vs. Sensorless FOC

For sensor FOC, the encoder can feedback the position information of the motor rotor, so the control is simple, but the control performance requirements are often high. For

sensorless FOC, it is necessary to collect the motor phase current and use the position estimation algorithm to calculate the rotor position. Therefore, the control is difficult, but the wiring is simple, the cost is low, and the reliability is high. It is mostly used in fan applications.

FOC case recommendation

The fourth phase of the Engineer Growth Program