كنترل مستقيم و مستقل توان اكتيو ماشين القايي دوسو تغذيه بدون استفاده از حسگر موقعيت روتور

چكيده انگليسي :

122 Direct Decoupled Active and Reactive Power Control of Doubly Fed Induction Machine without Rotor Position Sensors Navid Amiri n amiri@ec iut ac ir Date of Submission 2011 05 14 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Seyed Mohammad Madani madani104@yahoo comAbstract In recent years the matter of using renewable energy sources like solar or wind energy has become amajor concern due to the limited amount of fossil fuel The wind energy is one of the renewable energysources which have attracted many researchers in recent years Converting the wind kinetic energy toelectrical energy is done by the use of a wind turbine connected to an electrical generator One of thegenerators used for this purpose is the doubly fed induction machine In this machine the torque orelectrical power of the machine s stator can be controlled by feeding the rotor windings correctly Using theequivalent circuit of the DFIM we can express the stator active and reactive power in terms of stator androtor flux vectors The power equations show that the stator active and reactive power is in direct relation toboth magnitudes of the flux vectors and the angle between them With the stator being directly connected tothe grid the rotor flux can only be controlled by applying correct rotor voltages To achieve a goodperformance the power components control should be decoupled To achieve this the two axis model ofthe DFIM is used with the direct axis being placed on the stator flux vector Now the active and reactivepower of the stator can be controlled by controlling the quadrature and direct components of the rotor fluxrespectively By neglecting the stator resistance it can be assumed that the stator flux remains constantduring the operation With more precise analysis it can be seen that the existence of the stator resistancecan change both the magnitude and angle of the stator flux vector making the power control strategycoupled To overcome this problem in this thesis first the coupling between active and reactive power isanalized and the the reasons behind it are introduced Then the grid flux reference frame is used to make thepower equations unaffected by the changes in the reference frame angle afterwards a new method tocalculate the correct reference rotor flux vectors is introduced by predicting the stator flux from the powercommands with regards to the stator resistance Knowing the fact that the rotor current can be directlymeasured in a DFIM it can be used to estimate the rotor position by matching the measured and estimatedrotor current vectors therefor eliminating the need for a position sensor to be used in the method Toensure the correct estimation procedure for the rotor current comparison of the magnitudes of the measuredand estimated rotor current vectors is used to correct the magnetizing inductance value Simulation resultsshow the effectiveness of the proposed method in decoupled controlling of the stator power without theneed of rotor position sensors The results also show that the applied MRAS loop can correctly estimate thesteady state value of the machine magnetizing inductance To ensure the validity of the method anexperimental setup was prepared Practical results confirm the simulation results for the method s ability todecouply control the power without the need for a rotor position sensor Keywords Wind Energy Doubly Fed Induction Machine DFIM Direct Power Control DPC Direct Decoupled Power Control Sensorless control MRAS

اميري، نويد

كنترل مستقيم و مستقل توان اكتيو ماشين القايي دوسو تغذيه بدون استفاده از حسگر موقعيت روتور

انرژي باد , DFIM , كنترل مستقيم و مستقل توانDPC , sensorless , تخمين پارامتر , MRAS