Introduction to the top 10 technologies in the field of motor control

01. Integration is taking over the motor control market due to technological advances. Brushless DC motors (BLDC) and permanent magnet synchronous motors (PMSM) of various sizes and power densities are rapidly replacing motor topologies such as brushed AC/DC and AC induction.

02. Brushless DC motors/permanent magnet synchronous motors have the same mechanical structure, except for the stator winding. Their stator windings use different geometric structures. The stator is always opposite to the motor magnets. These motors can provide high torque at low speeds, so they are very suitable for servo motor applications.

03. Brushless DC motors and permanent magnet synchronous motors do not require brushes and commutators to drive the motors, so they are more efficient and reliable than brushed motors.

04. Brushless DC motors and permanent magnet synchronous motors use software control algorithms instead of brushes and mechanical commutators to drive the motor.

05. The mechanical structure of brushless DC motors and permanent magnet synchronous motors is simple. The motor has an electromagnetic winding on the non-rotating stator. The rotor is made of permanent magnets. The stator can be inside or outside and is always on the opposite side of the magnet. But the stator is always the fixed part, and the rotor is always the moving (rotating) part.

06. Brushless DC motors can have 1, 2, 3, 4 or 5 phases. Their names and driving algorithms may be different, but they are all brushless in nature.

07. Some brushless DC motors have sensors that help obtain the rotor position. Software control algorithms use these sensors (Hall sensors or encoders) to assist in motor commutation or motor rotation. These brushless DC motors with sensors are needed when the application needs to start under high load.

08. If the brushless DC motor does not have a sensor for obtaining the rotor position, a mathematical model is used. These mathematical models represent sensorless algorithms. In sensorless algorithms, the motor is the sensor.

09. Compared with brushed motors, brushless DC motors and permanent magnet synchronous motors have some important system advantages. They can drive the motor using electronic commutation schemes, which can improve energy efficiency by 20% to 30%.

10. Many products today require variable motor speeds. These motors require pulse width modulation (PWM) to change the motor speed. Pulse width modulation provides precise control of motor speed and torque, enabling variable speed.