the stator and rotor of SRM are of salient-pole cogging structure, and the stator and rotor cores are made of silicon steel sheets. Therefore, SRM has excellent characteristics such as simple and firm structure, good control performance and high efficiency. Therefore, Switched Reluctance Drive (SRD) has become a strong competitor of AC variable frequency speed regulation and brushless DC motor system, although it has a short development time. Because there is no winding on the rotor, no permanent magnet, and concentrated winding on the stator, SRD also has a unique fault operation ability, which is excellent at high speed and high temperature. Therefore, it is especially suitable for harsh working environment, such as underground shearer. SRM is a typical mechatronics motor, its control is very flexible, and it is easy to realize four-quadrant operation.
SRM is the executive component of SRD, and its structure and working principle are fundamentally different from traditional AC/DC motors. The rotor has neither windings nor permanent magnets, and the stator poles are wound with concentrated windings. SRM can be designed into a variety of structures with different phase numbers, and the pole numbers of stator and rotor have a variety of different collocations.
the operation of SRM follows the principle of minimum reluctance, that is, the magnetic flux always closes along the path of minimum reluctance, and when the iron core with a certain shape moves to the position of minimum reluctance, its main axis must coincide with the axis of magnetic field. When the stator A-A' pole is excited, the generated magnetic force tries to make the rotor rotate to the position where the rotor pole axis 3-3' coincides with the stator pole axis A-A', and maximize the inductance of the A-phase excitation winding. If the relative position of the stator and rotor in the drawing is taken as the starting position, the A→B→C→D phase winding is energized in turn, and the rotor will continuously rotate counterclockwise against the excitation sequence. Conversely, if the phase C→B→A→D is energized in turn, the motor will rotate clockwise. It can be seen that the steering of SRM has nothing to do with the current direction of the phase winding, but only depends on the order in which the phase winding is energized. In addition, as can be seen from Figure 1-2, when the main switching devices S and S are turned on, the A-phase winding absorbs electric energy from the DC power supply, while when S and S are turned off, the winding current continues to flow through the freewheeling diodes D and D and is fed back to the power supply.