What does permanent magnet brushless motor and brushless DC motor mean?
Speed control system composed of permanent magnet synchronous motor used to be called the sinusoidal permanent magnet synchronous motor (PMSM) speed control system; and the trapezoidal wave (Fang Bo) speed control system composed of permanent magnet synchronous motor, the principle and control methods of DC motor and similar, so this system for brushless DC motor (BLDCM) synchronous motor speed control system, Fang Bo is also known as the brushless DC motor (or square wave motor).
The permanent magnet synchronous motor rotor adopts permanent magnet, so that the rotor magnetic field in space distribution can be divided into sinusoidal and trapezoidal wave two kinds: one is sinusoidal waveform; the other is trapezoidal wave.
Permanent magnet brushless motor is usually divided into permanent magnet AC brushless motor and permanent magnet brushless DC motor. Permanent magnet brushless AC motor usually refers to AC synchronous motor. The permanent magnet brushless DC motor can be divided into two kinds of sinusoidal permanent magnet synchronous motor and brushless DC motor.
Brushless DC motor usually adopts a tile rotor magnet, through magnetic circuit design, can obtain the air gap magnetic trapezoidal wave density of stator winding with concentrated windings, so the Induction EMF is trapezoidal wave. The control of Brushless DC motor requires position information feedback. It is necessary to have a position sensor or a sensorless estimation technique to form an automatic speed regulation system. When controlling, each phase current is also controlled to square wave as much as possible, and the output voltage of inverter can be controlled according to the method of brush DC motor PWM. In essence, brushless DC motor is also a permanent magnet synchronous motor, and the speed regulation is also in the category of variable pressure variable frequency speed regulation. Generally, the permanent magnet synchronous motor with stator windings in three-phase distribution He Yongci rotor magnetic circuit structure and winding distribution ensure the Induction EMF waveform is sine, stator voltage and current applied should be sinusoidal, usually by AC voltage frequency. Permanent magnet synchronous motor (PMSM) control system usually adopts automatic control and position feedback information. Vector control (field oriented control) or direct torque control (DTC) can be adopted as the advanced control strategy. The difference between them can be considered as the design concept caused by square wave and sinusoidal wave control
