چكيده به لاتين
Electric motors are the main part of a traction system. In other words, choosing a suitable electric motor for the electric train propulsion system is a very important part of the whole system design. Therefore, efforts to reduce losses, cost, weight, dimensions and improve the performance of electric motors used in the traction system have always been of special importance. In recent years, attention and use of synchronous electric motors in traction systems have increased and these electric motors have become an attractive and reliable alternative to induction and direct current electric motors. Among the different types of synchronous electric motors, synchronous reluctance electric motors have attracted a lot of interest due to their simple structure, absence of magnets and coils in the rotor, lower losses, higher efficiency and economic efficiency. Speed control of synchronous reluctance motors is one of the main challenges related to these motors. Vector control is one of the conventional methods to control the speed of synchronous reluctance motors, which has received more attention due to its simplicity and less Computational cost. In fact, this method transforms three-phase complex synchronous reluctance electric motors into a separate excitation direct current motor where the flux and torque are controlled in two different channels. Reaching the conditions of maximum torque per amper can also improve the overall performance of synchronous reluctance electric motors. Under these conditions, for the optimal stator current, the total losses of the synchronous reluctance motor are reduced and as a result, its efficiency increases. Traditionally, the accurate speed control of the system depends on the shaft encoder, but the presence of this encoder increases the volume and cost of the control system. Therefore, the use of sensorless speed control methods has been considered. The sensorless speed control methods of synchronous reluctance motors are in two categories: methods based on the basic model of the motor and methods based on the inherent saliency of the rotor. In the meantime, sensorless speed control method based on active flux due to its simple concept, low Computational cost and low dependence on changes in machine parameters and control method based on sliding mode due to its simplicity of implementation and usability in all types of electric motors have received more attention
