Analysis flux linkage measurement method without using rotor clamping device for switched reluctance motors

Obtaining flux linkage characteristics is the first step of designing a high performance torque controller or an accurate position sensorless control system for switched reluctance motors. Flux characteristics can be measured experimentally or calculated by finite-element or geometry-based methods. DC excitation is an accurate and simple method widely used to measure flux profile. One drawback of this method is requirement of clamping devices for locking rotor during measurement operation. In this paper the possibility of eliminating rotor clamping devices in DC excitation method is analyzed. Although, lack of clamping devices may cause rotor to rotate, but here some solutions are introduced to minimize this error. In addition three methods are proposed to calculate and predict maximum rotor angle changes without using any position sensor. For verifying and validating these methods a simulation is done on a 12/8 SRM motor and its results are analyzed. Because locking rotor is mostly done manually by operators, the proposed method can be used as core of an automatic approach for universal SRM drives to obtain flux linkage profile.