: Switched Reluctance Motor (SRM) possesses many merits, such as simple structure, low manufacturing cost, high torque and high reliability. In recent years, due to increasing cost of magnets, Permanent Magnet (PM) motors lose their economic advantages in some applications, therefore SRMs are becoming an attractive candidate. But, SRM has some disadvantages which restrict its wide usage. Torque ripple and need for position sensors are the main drawbacks. Torque ripples cause acoustic noise and produce vibration in motor structure and its nearby devices. Position Sensors are almost expensive, and reduce the reliability of the drive system. Nowadays, there are many methods to overcome these problems, but these methods almost require motor characteristics. Most of practical methods for obtaining motor characteristics need a device to clamp the rotor in specific angles. These devices, increasing the cost and cannot be used while the motor is in service. Due to manually fix of clamping device, these methods cannot be done automatically, therefore eliminating rotor clamping device is an effective step to design SRM universal drives which can automatically obtain motor characteristics. In this thesis, a new method to obtain motor characteristic without using a clamp device is introduced. The proposed method is based on this fact that mechanical time constant of the motor is greater than the electrical time constant. Consequently, under special condition in the traditional method, rotor can leave free and not clamped. First, the proposed method is analyzed assuming there is a position sensor in the drive system. One of the most challenging subjects of the proposed method is determining rotor angle changes during operation and its impact on flux profile accuracy. For this purpose in the second stage, five methods are engaged to calculate the rotor angle movement before or after operation. To ensure the quality and accuracy of the proposed method, a simulation is done on a 4kW 8/6 SRM four-phase and an 80W 12/8 three-phase SRM. The results of this simulation indicate that rotor movement and flux error are too small and can be neglected. Also rotor movement calculation methods show reasonable results for predicting and calculating rotor angle changes. To verify these results, an SRM drive is implemented and a practical experiment is done on these two motors. Finally, a comparison is done between the proposed method and traditional methods. Keywords: Switched Reluctance Motor (SRM), Flux Linkage Measurement, Obtaining Motor Characteristics, Rotor Clamping Devices, Position Sensor
