Switched reluctance motor noise reduction design, vibration reduction design, torque ripple control design, no position sensor, and control strategy design have been the research hotspots of SRM. Among them, the control strategy design based on modern control theory is to suppress noise, vibration and Torque ripple service.
1. The noise and vibration of the SRM suppress the noise and vibration of the
switched reluctance motor, which is the main bottleneck restricting the promotion of the SRM. Due to the double-convex structure, the control method of the asymmetric half-bridge and the non-sinusoidal air-gap magnetic field, the SRM has inherent noise, The vibration is larger than that of asynchronous motors and permanent magnet motors, and there are many high-frequency components, the sound is sharp and piercing, and the penetrating power is strong. The research ideas of noise reduction and vibration reduction are generally divided into several directions:
1) Modal analysis, study the influence of frame, stator and rotor shape, end cover, etc. on each order mode, analyze the natural frequency under each order mode, Investigate how the electromagnetic excitation frequency is far away from the natural frequency of the motor.
2) Reduce noise and vibration by changing the shape of the stator and rotor, such as changing the ji arc, shape, yoke thickness, key position slotting, oblique groove, punching, etc.
3) There are many novel motor structures invented, but all of them have problems. Either the manufacturing is difficult, the cost is high, or the loss is large. Without exception, they are all laboratory products and things born for the thesis.
2. The torque pulsation control of the switched reluctance motor
basically starts with control. The general direction is to control the instantaneous torque or improve the average torque. There are closed-loop control and open-loop control. The closed-loop control requires torque feedback or through current, Variables such as voltage calculate torque indirectly, and open-loop control is basically a table lookup.
3. Research on position sensor of switched reluctance motor
The direction without position sensor is a major producer of papers. In theory, there are harmonic injection methods, inductance prediction methods, etc. Unfortunately, there are no position sensors in mature industrial products at home and abroad. Why? I think it is still because of unreliability. In industrial applications, an unreliable location information may cause accidents and losses, which are unbearable for enterprises and users. SRM’s current reliable position detection methods include low-resolution position sensors represented by photoelectric switches and Hall switches, which meet the commutation requirements of motors in general occasions, and high-precision position sensors represented by photoelectric encoders and resolvers. Meet the need for more accurate control.
The above is the main content of the switched reluctance motor. Among them, the split type resolver is very suitable for the use of SRM, with small size, high precision and good environmental adaptability. I think it is the inevitable choice for servo SRM in the future.
Post time: Apr-27-2022