Switched reluctance motor
Switched reluctance motor, also known as reactive synchronous motor, the rotor of the motor itself is not magnetic, but the principle of using the movable part of the magnetic field to minimize the magnetic reluctance of the magnetic circuit, that is, the magnetic flux is always along the path with the smallest magnetic resistance. Closing, due to the distortion of the magnetic field, produces a tangential pulling force. Therefore, its structural principle is to require the largest possible change in the magnetic resistance of the magnetic circuit when the rotor rotates.
The torque is generated by the difference in the reluctance of the two orthogonal directions of the rotor. This torque is called reluctance torque or reactive torque.
The specific working process of the switched reluctance motor is shown in the figure (only one phase is shown).
When the A-phase winding control switches S1, S2 are closed, a current flows in the A-phase winding, and a tangential force is generated, which attracts the rotor to rotate in the direction in which the A-phase winding rotor tooth axis and the stator pole axis coincide with each other, that is, the suction rotor counterclockwise direction Rotate. When the rotor and the B-phase stator are aligned, the phase A is turned off, the phase B is turned on, the tangential force generated continues to attract the rotor to rotate counterclockwise, and so on, and the conduction of C, A, and B continues, and the rotor continues to follow. Rotate counterclockwise to output mechanical energy. Conversely, if the conduction phase changes from phase A to phase C and then from phase C to phase B, cycling in this phase sequence energizes the rotor in a clockwise direction. It can be seen that the rotor steering is independent of the current direction of the phase windings, only depending on the order in which the phase windings are energized.
When the main switching devices S1 and S2 are simultaneously turned on, the A-phase windings absorb power from the DC power source U; when S1 and S2 are simultaneously turned off, the winding current passes through the two freewheeling diodes and continues to circulate, and the remaining power is fed back to the power supply. U. Therefore, the switched reluctance motor has the ability to regenerate electric energy, so the power loss is relatively small and the system efficiency is high.
