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Automatic separation of the working process and position of automatic separation permanent magnetic DC motor

Jun 20, 2019

In the process of automatic separation of automatic separation permanent magnetic DC motor, in each state, only two phase windings are energized, and one state is changed in turn. The axis of the magnetic field generated by the stator winding is rotated by 60° in space, and the rotor follows the stator magnetic field. Corresponding to the 60° electrical angular space position, the rotor is in a new position, so that the position sensors U, V, W generate a new set of codes according to the convention. The new code changes the conduction combination of the power tubes to make the magnetic field generated by the stator windings. The shaft is further advanced by 60° electrical angle. In this cycle, the permanent magnet DC motor will generate continuous torque and drag the load for continuous rotation. Just because the commutation of the permanent magnet DC motor is generated by itself, rather than being forcedly reversed by the inverter, it is also called a self-controlled synchronous motor.


The position sensor code of the automatic separation permanent magnet DC motor makes the position of the combined two-phase winding magnetic field axis ahead of the rotor magnetic field axis position, so the motor will generate a sufficient starting torque at the starting moment regardless of the starting position of the rotor. Therefore, no additional starting winding is required on the rotor.


The automatic separation of permanent magnet DC motor can be regarded as perpendicular to the rotor axis due to the stator magnetic field axis. When the core is not saturated, the average electromagnetic torque generated is proportional to the winding current, and the current-torque characteristic of the separately excited DC motor. same. Whether the load changes, the power supply voltage changes, or the ambient temperature change, when the rotational speed is lower than the commanded rotational speed, the feedback voltage Vfb becomes smaller, the duty ratio δ of the modulated wave becomes larger, the armature current becomes larger, and the electromagnetic generated by the motor is generated. The torque increases to generate acceleration until the actual speed of the motor is equal to the commanded speed.