Direct Torque Control Of SRM

The Switched Reluctance Motor system has excellent performance of speed adjustment, simple structure, high reliability and lower cost. It has so many advantages. Every coin has two sides. Its unique structure also leads advantage such as its serious torque ripple. The Switched Reluctance Motor has many parameters that can be controlled to adjust speed, for instance the phase voltage on the winding, the turn-on angle and the turn-off angle. The system needs different control strategy for different speed zone because of its highly nonlinear characteristic. Therefore its control scheme is very complex. The direct torque control is famous for its unique control concept and simple scheme. The thesis is aimed to apply the Direct Torque Control on the Switched Reluctance Motor.The thesis introduces the basic structure, elementary functions, and operation characteristics of Switched Reluctance Motor. It deduces the direct torque control for Switched Reluctance Motor compared with the method used on the inductive motor. It sets the control aim for Switched Reluctance Motor. It defines the voltage vector for Switched Reluctance Motor. It studies the selection of voltage vectors according to the operation characteristics. It chooses several voltage vectors as active voltage vectors. And three look-up sheets are set relatively. The thesis gives an novel technique for torque estimation. Then the problems such as linkage control and the torque regulation are investigated.The following is the analysis for SRM torque characteristics. It gives own opinion for the root of torque ripple production and torque ripple classification. It compares the methods which are used to restrain the torque ripple. The direct torque control is capable to regulate the torque for it has torque feedback loop. It applies the direct torque control to solute the torque ripple and proves it with the simulation.