Enhanced torque control in a DFIG connected to a DC grid by a diode rectifier

This paper considers the control of a doubly fed induction machine (DFIG) connected to a dc-bus or dc-grid by using a diode rectifier placed on the stator-side and a single PWM converter on the rotor. In this system, the torque and the frequency have to be regulated simultaneously, in order to make the prime mover operating at the maximum power point and to guarantee at the same time a flux level near the rated value. Since this system is based on a unique reduced-power controlled converter and a diode rectifier, a noticeable reduction of the costs of the power electronics can be achieved. However, the diode bridge causes stator current and voltage harmonics which produce a noticeable torque ripple. A regulation scheme able to reduce the torque ripple is proposed in this paper: resonant current controllers are implemented to track the sixth harmonic components in the reference rotor current commands, in such a way to kill the corresponding harmonic in the electromagnetic torque.

[1]  Roberto Cárdenas,et al.  Overview of control systems for the operation of DFIGs in wind energy applications , 2013, IECON 2013 - 39th Annual Conference of the IEEE Industrial Electronics Society.

[2]  Hiroaki Kakigano,et al.  Low-Voltage Bipolar-Type DC Microgrid for Super High Quality Distribution , 2010, IEEE Transactions on Power Electronics.

[3]  Heng Nian,et al.  A novel DC grid connected DFIG system with active power filter based on predictive current control , 2011, 2011 International Conference on Electrical Machines and Systems.

[4]  A. Di Gerlando,et al.  Simulation and test results of grid connected WECSs with diode rectifiers and modular PMSGs , 2010, The XIX International Conference on Electrical Machines - ICEM 2010.

[5]  Lingling Fan,et al.  Harmonic Analysis of aD FIG for aW ind Energy Conversion System , 2010 .

[6]  Matteo F. Iacchetti,et al.  Inner Control Method and Frequency Regulation of a DFIG Connected to a DC Link , 2014, IEEE Transactions on Energy Conversion.

[7]  J. Clare,et al.  MRAS observer for sensorless control of standalone doubly fed induction generators , 2005, IEEE Transactions on Energy Conversion.

[8]  Gil D. Marques,et al.  Operation and design issues of a doubly fed induction generator stator connected to a dc net by a diode rectifier , 2014 .

[9]  Jiabing Hu,et al.  Operation of Wind-Turbine-Driven DFIG Systems Under Distorted Grid Voltage Conditions: Analysis and Experimental Validations , 2012, IEEE Transactions on Power Electronics.

[10]  R. Perini,et al.  A MRAS observer applied to sensorless doubly fed induction machine drives , 2010, 2010 IEEE International Symposium on Industrial Electronics.

[11]  A. Di Gerlando,et al.  Analysis and comparison of different diode rectifiers solutions in grid connected WECS employing modular PMSGs , 2010, The XIX International Conference on Electrical Machines - ICEM 2010.

[12]  G. D. Marques,et al.  Stator Frequency Regulation in a Field-Oriented Controlled DFIG Connected to a DC Link , 2014, IEEE Transactions on Industrial Electronics.

[13]  Giovanni Maria Foglia,et al.  Comprehensive steady-state analytical model of a three-phase diode rectifier connected to a constant DC voltage source , 2013 .

[14]  Hong-Hee Lee,et al.  Control Strategy for Harmonic Elimination in Stand-Alone DFIG Applications With Nonlinear Loads , 2011, IEEE Transactions on Power Electronics.

[15]  J.A.M. Bleijs.  Continuous Conduction Mode Operation of Three-Phase Diode Bridge Rectifier with Constant Load Voltage , 2005 .

[16]  Gil D. Marques,et al.  A Scheme for the Power Control in a DFIG Connected to a DC Bus via a Diode Rectifier , 2015, IEEE Transactions on Power Electronics.

[17]  Guillermo O. García,et al.  Adaptive Observer for Sensorless Control of Stand-Alone Doubly Fed Induction Generator , 2009, IEEE Transactions on Industrial Electronics.

[18]  Lingling Fan,et al.  Harmonic Analysis of a DFIG for a Wind Energy Conversion System , 2010, IEEE Transactions on Energy Conversion.

[19]  Michael Negnevitsky,et al.  A Novel Control Strategy for a Variable Speed Wind Turbine with a Permanent Magnet Synchronous Generator , 2008, 2008 IEEE Industry Applications Society Annual Meeting.

[20]  Heng Nian,et al.  Dynamic Modeling and Improved Control of DFIG Under Distorted Grid Voltage Conditions , 2011, IEEE Transactions on Energy Conversion.

[21]  Cassiano Rech,et al.  Integrated Full-Bridge-Forward DC–DC Converter for a Residential Microgrid Application , 2013, IEEE Transactions on Power Electronics.

[22]  Dong Chen,et al.  Control and Operation of a DC Microgrid With Variable Generation and Energy Storage , 2011, IEEE Transactions on Power Delivery.

[23]  D. Borojevic,et al.  Modeling and control of a synchronous generator with an active DC load , 2000 .

[24]  F. Blaabjerg,et al.  Power electronics as efficient interface in dispersed power generation systems , 2004, IEEE Transactions on Power Electronics.

[25]  F. Liu,et al.  DC Bus Voltage Control for a Distributed Power System , 2003 .

[26]  G D Marques,et al.  A DFIG Sensorless Rotor-Position Detector Based on a Hysteresis Controller , 2011, IEEE Transactions on Energy Conversion.

[27]  Dehong Xu,et al.  Stator Current Harmonic Control With Resonant Controller for Doubly Fed Induction Generator , 2012, IEEE Transactions on Power Electronics.

[28]  Jon Clare,et al.  Doubly fed induction generator using back-to-back PWM converters and its application to variable-speed wind-energy generation , 1996 .