Position Sensorless Technology Of Switched Reluctance Motor Drives Considering Mutual Inductance

Switched reluctance motor(SRM)which has the following advantages such as simple strong structure, small startup current, strong fault-tolerant operation ability and big start torque has been widely used in electric vehicle drive, mining, household appliances, and many other fields. But, position sensor used to detect the rotor position information will make SRM structure complex,increase cost,reduce reliability and limit the spread of SRM. Therefore, the sensorless technology research of SRM has high academic and application value. Because conduction angle of each SRM phase is usually larger than its step angle, the motor often works in two-phase excitated mode at the same time in order to improve the torque output capacity in practical engineering application. At this point, coupling magnetic field exists between two excitated phases and mutual flux linkage will lead to great influence to flux linkage and inductance, which also influence rotor position estimation precision based on flux linkage and inductance model. T Sensorless rotor position estimation method of eliminating mutual inductance influence which based on the SRM nonlinear sensorless control technology was proposed in this paper. This method can eliminate the mutual inductance influence to rotor position estimation, without measuring the size of mutual inductance.Firstly, the research status of sensorless control technology and mutual inductance at home and abroad were introduced and summarized in this paper, basic working principle, basic mathematical equations and general control methods of SRM are introduced.Secondly, the 18.5 kW SRM simulation model was built up by finite element analysis software Ansoft Maxwell to research the motor magnetic properties and the 2D simulation was done in this paper. The self-inductance and mutual inductance features of SRM at different excitated situations were researched, and a kind of self-induction flux online obtained method based on a half cycle excitated condition were introduced. Thirdly, the rotor angle estimated schemes were given respectively when SRM working at the single-phase excitated and two-phase excitated situations. Rotor angle estimated scheme based on nonlinear inductance model at the single-phase excitated mode was analyzed. Rotor angle estimated scheme at the two-phase excitated mode was proposed by discussing mutual inductance influence of the rotor angle estimated. The inductance-difference of the two excitated phases was obtained by flux linkage-difference method.Self-inductance value of the previous phase was got according to the online forecast method And then self-inductance value of reference phase at the two-phase excitated mode can be obtained. Proposed nonlinear self-inductance model is used to estimate rotor position under the obtained self-inductance value at angle estimated region. The sensorless control algorithm was simulated by MATLAB to verify its feasibility. Finally, the sensorless SRM start initial rotor position estimation strategy based on excitation pulse method was adopted and a simulation was carried out in this paper.Finally, the hardware implementation platform and the software design of the sensorless control system were introduced in the paper. On this basis, the feasibility of the proposed sensorless control algorithm was verified by experiments, and the experiment results were analyzed and summarized in this paper.