An Improved Grid-connected Control Strategy of Double PWM Direct-drive Permanent-magnet Synchronous Wind Generators

摘要

Based on the speed loop characteristics analysis of direct-drive permanent magnet synchronous wind turbines, a closed-loop transfer function of speed control for the generator-side PWM converter is deduced. To eliminate the non-origin closed-loop zero in the transfer function and to enhance system dynamic characteristics under disturbances, an improved control strategy is proposed and applied to the control of the grid-side converter. A model of double PWM direct-drive permanent magnet wind power generation system with the proposed grid-connected control strategy is established with MATLAB/SIMULINK. Results show that the overshoots of the dynamic response in the generator-side and grid-side control systems can be reduced by using the modified control strategy, and the stability of grid-connected operation for the whole direct-drive permanent magnet wind power generation system can be improved.