كاهش تلفات اهمي درايو يوئيچ رلكتانس در روش كنترل مستقيم گشتاور

چكيده انگليسي :

Copper loss reduction in SR drives with DTC method Mahdi Abdolhamidy m abdolhamidy@yahoo com Date of Submission Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Sayed Morteza Saghaiannezhad saghaian@cc iut ac ir Abstract As a variable speed drive the SRM has many attractive features which revived the interest in this driveafter the development of fast power switching devices and digital controllers SRM has rather simpleconstruction and can be manufactured with low cost Because of its high torque to inertia ratio and inherentspeed controllability it is currently considered as a valuable candidate as a principle drive for variable speedapplications The SRM also excels with high reliability and fault tolerance capability The primarydisadvantage of an SRM is the higher torque ripple compared with conventional machines which contributesto acoustic noise and vibration The origin of torque pulsations in a SRM is due to the highly nonlinear anddiscrete nature of torque production mechanism The total torque in an SRM is the sum of torques generatedby each of the stator phase which are controlled independently Torque pulsations are the most significant atthe commutation instants when torque production mechanism is being transferred from one active phase toanother The minimization of the torque ripple is essential in high performance servo applications whichrequire smooth operation with minimum torque pulsations There are essentially two primary approaches forreducing the torque pulsations one method is to improve the magnetic design of the motor while the other isto use sophisticated electronic control Machine designers are able to reduce the torque pulsations by changingthe stator and rotor pole structures but only at the expense of motor performance The electronic approach isbased on selecting and optimum combination of the operating parameters which include the supply voltage turn on and turn off angle current level and the shaft load In a switched reluctance motor with availablecharacteristics and with conventional asymmetric power electronic converter it s possible to reduce torqueripple with several methods such as nonlinear control optimization control and direct torque control DTCmethod has many advantages over other control methods such as simple algorithm less torque ripple andneedless to turn on and turn off angle In this thesis first principles of direct torque control are studied andconventional DTC method for SRM in the base of comparing with AC motor is investigated then a method forperformance improving and copper loss reducing under direct torque control is proposed At the end simulation and experimental results for conventional and proposed method are obtained and compared Simulation results with Simulink MATLAB software are presented and analyzed Also experimental resultsare achieved with SRM drive laboratory setup and simulation results are verified Keywords switched reluctance motor direct torque control Copper loss reduction efficiency improvement

عبدالحميدي، مهدي

كاهش تلفات اهمي درايو يوئيچ رلكتانس در روش كنترل مستقيم گشتاور

موتور سوئيچ رلكتانس , كاهش تلفات مسي , افزايش بازدهي