The Research On Inductance Sensorless Control Methods Of Switched Reluctance Motor

Due to its simple structure, reliable work and high fault tolerance, switched reluctance motor (SRM)has superior working performence in harsh environment, especially in the extreme conditions of hightemperature, high pollution, strong electromagnetic interference and nuclear radiation. SRM hasreceived wide application in aerospace, electric vehicles, ships, flywheel energy storage, textilemachinery and other fields. However, the operation stability of SRM depends on accurate rotorposition information. External position sensors not only increase the cost and volume of SRM, butalso deteriorate the reliability of operation in harsh environment. Hence, the research of sensorlesstechnology has great industrial application value.In this paper, the basic theory of SRM is introduced. The basic equations and mathematical modelsare summarized as well as the control modes of SRM.A sensorless algorithm based on regional comparison of calculated three-phase inductance isproposed. The logic relationship of phase inductance varies regionally with the change of rotorposition. The rotor position can be divided into several regions, position pulse signal of each phase isobtained by recognizing position regions. According to position pulse signals, rotor position can beestimated and then sensorless operation is achieved. Considering the different conditions caused bythe change of turn-off angle, this methed analyzed each condition and a unified position estimationalgorithm is carried out. Simulation and experimental results have verified the validity of the method.The algorithm mentioned above is lack of fault tolerance because of the inductance information ofeach phase is needed. A new algorithm using the crossing point of transformer EMF and back EMF ispresented to increase fault-tolerant ability. The crossing point position can be derivate frominductance mode, and it is regarded as a reference point to estimate rotor position. Because of thetraditional inductance mode can not use to calculate the overlap point, a new inductance mode ofSRM is proposed. Simulation and experimental results have verified the validity of the method.Finally, the system hardware platform and software design are introduced. The hardware platformconsists of power circuit, digital control circuit, voltage and current detection circuit and so on. Thesoftware discusses the design of two sensorless control technologes above.