| Recently, Development of wind energy in the world has achieved anunprecedented degree. VSCF doubly-fed wind generator is the mainstream model inwind power fields. The scale of the parallel operation of wind power connected ingrid will have negative effects. Improving VSCF wind power generation systemoutput power quality to ensure the network voltage stability has importantsignificance. Because of the existence of the internal electronic devices in Doubly-fedgenerators, output voltage generator with higher harmonic has some negative effectson power system, such as resonance, low efficiency, Motor Burnout, and so on.The power quality of DFIG which adopts cycloconverter cannot meet the need ofpower system because of harmonics in the output voltage of cycloconverter. Two casestudies are considered, namely: non-sinusoidal rotor injection; an unbalanced statorload scenario. In both scenarios, Fourier analysis is used to resolve the non-sinusoidalwaveform currents into the fundamental component and a series of harmoniccomponents. The model of DFIG established under synchronization reference framein this paper, Simulation model of active and reactive decoupling control with thestator flux oriented vector control is built in MATLAB/SIMULINK. The harmoniccomponents of the stator and rotor currents are calculated and the simulation resultsagree well with the results from analysis. Through the actual data of electric powertest proved in normal working conditions, the reactive power compensation andharmonic control equipment to improve the voltage stability of an important role. |
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