Calculation of Core and Stray Load Losses in Brushless Doubly Fed Induction Generators

The brushless doubly fed induction generator (BDFIG) has substantial benefits, which make it an attractive alternative as a wind generator. However, it suffers from lower efficiency and larger dimensions in comparison with the doubly fed induction generator. A major part of drawbacks arises from undesirable spatial harmonics of air-gap magnetic field. Calculation of core loss is an important issue in optimal design studies to improve the performance characteristics. The iron loss is higher and has a more complex nature in BDFIGs in contrast with conventional machines. Furthermore, additional losses cannot be ignored due to a high level of spatial harmonics distortion. This paper aims to formulate core loss and stray load loss (SLL) in BDFIGs based on the design data and experimental parameters provided by electrical steel manufacturers. In addition, an analytical procedure for calculating spatial harmonic components of the stator and rotor magnetic fields is presented. The acceptable accuracy of the theoretical equations is verified by comparing the calculated core loss and SLL of a D-180 prototype BDFIG with the measured data. The results show that SLL in BDFIGs is higher than the predicted per-unit values given by standards for induction machines, e.g., IEC 60034 ~ 2 and NEMA MG1.

[1]  C. Ragusa,et al.  Predicting loss in magnetic steels under arbitrary induction waveform and with minor hysteresis loops , 2004, IEEE Transactions on Magnetics.

[2]  Hashem Oraee,et al.  A novel rotor configuration for brushless doubly-fed induction generators , 2013 .

[3]  Hashem Oraee,et al.  Electromagnetic-Thermal Design Optimization of the Brushless Doubly Fed Induction Generator , 2014, IEEE Transactions on Industrial Electronics.

[4]  Ion Boldea,et al.  The Induction Machine Handbook , 2001 .

[5]  Teng Long,et al.  Dynamic Control of the Brushless Doubly Fed Induction Generator Under Unbalanced Operation , 2013, IEEE Transactions on Industrial Electronics.

[6]  Babak Fahimi,et al.  Optimal Design of Doubly Fed Induction Generators Using Field Reconstruction Method , 2010, IEEE Transactions on Magnetics.

[7]  T.J.E. Miller,et al.  On the variation with flux and frequency of the core loss coefficients in electrical machines , 2006, IEEE Transactions on Industry Applications.

[8]  Hashem Oraee,et al.  Generalized Vector Model for the Brushless Doubly-Fed Machine With a Nested-Loop Rotor , 2011, IEEE Transactions on Industrial Electronics.

[9]  Wenping Cao,et al.  Comparison of Stray Load and Inverter-Induced Harmonic Losses in Induction Motors Using Calorimetric and Harmonic Injection Methods , 2010 .

[10]  Andrea Cavagnino,et al.  International standards for the induction motor efficiency evaluation: a critical analysis of the stray-load loss determination , 2003 .

[11]  F. Blazquez,et al.  Characterization of the Rotor Magnetic Field in a Brushless Doubly-Fed Induction Machine , 2009, IEEE Transactions on Energy Conversion.

[12]  Richard McMahon,et al.  Performance Description of Brushless Doubly-Fed Induction Machine in Its Asynchronous and Variable Speed Synchronous Modes , 2011 .

[13]  Shiyi Shao,et al.  Low-Cost Variable Speed Drive Based on a Brushless Doubly-Fed Motor and a Fractional Unidirectional Converter , 2012, IEEE Transactions on Industrial Electronics.

[14]  Alan K. Wallace,et al.  Investigation of appropriate pole number combinations for brushless doubly-fed machines applied to pump drives , 1994 .

[15]  Marco Liserre,et al.  Overview of Multi-MW Wind Turbines and Wind Parks , 2011, IEEE Transactions on Industrial Electronics.

[16]  Hashem Oraee,et al.  A Novel Modeling Approach for Design Studies of Brushless Doubly Fed Induction Generator Based on Magnetic Equivalent Circuit , 2013, IEEE Transactions on Energy Conversion.

[17]  M. Pastorelli,et al.  International standards for the induction motor efficiency evaluation: a critical analysis of the stray-load loss determination , 2003, 38th IAS Annual Meeting on Conference Record of the Industry Applications Conference, 2003..

[18]  P. Biringer,et al.  A simple method of estimating the minor loop hysteresis loss in thin laminations , 1978 .

[19]  Sajjad Tohidi,et al.  Analysis and Enhancement of Low-Voltage Ride-Through Capability of Brushless Doubly Fed Induction Generator , 2013, IEEE Transactions on Industrial Electronics.

[20]  Zhe Chen,et al.  Overview of different wind generator systems and their comparisons , 2008 .

[21]  M. Aoulkadi,et al.  When loads stray: Evaluation of Different Measurement Methods to Determine Stray Load Losses in Induction Machines , 2008, IEEE Industrial Electronics Magazine.

[22]  B. Heller,et al.  Harmonic field effects in induction machines , 1977 .

[23]  Emmanuel B. Agamloh,et al.  An Evaluation of Induction Machine Stray Load Loss From Collated Test Results , 2009, IEEE Transactions on Industry Applications.

[24]  L. Ferraris,et al.  Induction Motor Equivalent Circuit Including the Stray Load Losses in the Machine Power Balance , 2007, IECON 2007 - 33rd Annual Conference of the IEEE Industrial Electronics Society.

[25]  R. D. De Doncker,et al.  Calculation of losses in ferro- and ferrimagnetic materials based on the modified Steinmetz equation , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[26]  S. Morimoto,et al.  Prediction of iron loss in rotating machines with rotational loss included , 2003 .

[27]  P. C. Roberts,et al.  Performance of the bdfm as a generator and motor , 2005 .