| With rapid growth of economy and increasing of power demand, wind power industry has the potential of dominating the world market in order to make electrical energy supply diversified and carbon emissions reduced simultaneously. At present, with wind power industry developing fast in our country, the difficulty of wind power grid-connected is still not solved thoroughly, wind power grid technology is one of the reasons, except for government policies. Therefore how to connect with power grid for wind power with high quality steadily becomes much-needed issue.Grid-connected control related problems in direct-drive wind system is studied in the article, improved space vector pulse width modulation (SVPWM) technology is applied to wind power grid inverter control, which has smaller harmonic, higher DC voltage utilization ratio, the current PI adjuster control is used in order to make the output current track fast given current and realize unit power factor grid-connected, the voltage PI closed-loop control is also used in order to maintain DC voltage constant, namely double closed loop control structure. The three-phase voltage inverter is studied in-depth, the basic principle and control algorithm of the improved SVPWM modulation technology is analyzed in detail, the overall structure of wind power grid inverter part based on double closed loop control and SVPWM control is constituted. Improved SVPWM control algorithm simulation make use of MATLAB SIMULINK dynamic simulation tool is achieved, and wind power grid inverter is controlled respectively by means of improved SVPWM and traditional SVPWM control algorithm, and the two control simulation results are analyzed, it is concluded that harmonic content of the grid current is less, total harmonic distortion rate is lower with the improved SVPWM control, and the unit power factor grid connected is realized, it has practical meaning to direct-drive wind power grid-connected system. |
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