| Switched Reluctance Motor(SRM) is doubly salient structure which is simple and rugged. The rotor has no permanent magnet or windings while the stator is wound with concentrated winding. Owning to few motor manufacturing processing steps and low-cost structure, SRM is especially suitable for high speed, high temperature or bad industrial and mining working environment conditions. However the closed-loop operation system needs the rotor position sensor which increases the cost and complexity of the system and reduces the reliability and robustness of the SRD system, so the sensorless technology of SRM becomes a research hotspot.In this paper, sensorless methods for both initial position and high speed running conditions of SRMs have been investigated. Also fault-tolerant estimation algorithm when the system failed to capture the rising or falling edge impulse of position signal has been studied which improved the reliability and robustness of the proposed sensorless technology in the actual operation environment.In view of the initial position estimation, this paper proposed a method which compares the rising time of the three phase-current when the pulse current peak is fixed. Based on the analysis on the principle of pulse injection method, the paper parsed the relationship of rotor position, phase inductance and phase current at zero speed. The proposed method used to determine the initial conduction phase is easy to realize without complex calculation. The experiment and simulation results verified the correctness of the algorithm.In order to measure motor flux, this paper sets up flux measurement platform based on ds PACE1104 and mechanical index apparatus. The paper studied the measurement and optimizing process of the phase flux which is easy and convenient to realize. According to the structure characteristic of SRM, in the largest and minimum inductance area, there exists convex plate which caused a small error of the initial position. In face of this, the paper puts forward an arithmetic mean method based on the symmetry of phase inductances which improved the accuracy of the characteristics position flux and paved the way for the subsequent sensorless technology.The indirect position detection method used in this paper is improved simplified flux modified based on the characteristics position flux. In view of the heavy burden of the processor caused by the three-dimensional table of rotor position, phase current and flux, this paper proposed a modified exponential function of flux modeling method. The comparison and analysis results validated the new flux model has higher precision.Based on the analysis of structure characteristics of the three-phase 12/8 pole SRM, the paper puts forward the sensorless technology used single feature position of 15°. The principle is simple, easy to implement and can be widen to other SRMs. In the experiment, due to the loss of even one single pulse signal, the motor can be stopped. Aimed at solve this, the fault-tolerant strategy is put forward. The original algorithm is improved to obtain the position signals by magnetic properties of current conduction phase. By delaying angle, the edge trigger pulse of position is determined. Then the paper puts forward the suitable fault-tolerant strategy for both single-phase fault and two-phase fault conditions. Finally the correctness of the above theory is verified by simulations and experiments. |
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