EXTREMUM SEEKING-BASED CONTROL METHOD FOR MAXIMUM OUTPUT TRACKING OF A WIND TURBINE GENERATOR

摘要

The present invention discloses an extremum seeking-based control method for maximum output tracking of a wind turbine generator, mainly comprising three steps of first closed-loop feedback, second closed-loop feedback, and third closed-loop feedback. The method for resisting mechanical fatigue of a double-fed variable speed constant frequency wind turbine generator by controlling mechanical torque while capturing maximum wind energy provided in the present invention is applied to a double-fed variable speed constant frequency wind turbine system by improving the control based on sliding mode extremum seeking with the following effects that, with regard to the maximum wind energy tracking effect, the rotating speed can be quickly adjusted to keep the tip speed ratio λ as its optimum value after the wind speed changes, so that the wind energy utilization coefficient is restored to the maximum value.

主权项

1. An extremum seeking-based control method for maximum output tracking of a wind turbine generator, characterized in that, the sliding mode extremum seeking-based control method for realizing maximum output tracking of the wind turbine generator comprises the following steps:
first closed-loop feedback for generating a feedback value of an output active power ps; the specific signaling process comprises comparing the active power ps output by a double-fed motor and a power reference value ps,ref, delivering the difference ε to a sign function sgn(ε), producing a sliding mode action when sgn(ε) changes, delivering the information to a module v0/s after multiplying by a constant u, thus obtaining a reference value ωr,ref of the rotating speed, and obtaining the active power ps according to a WCES image and feeding the active power ps back to the power reference value ps,ref, thereby forming power closed-loop feedback; second closed-loop feedback for generating a feedback closed-loop system of the difference ε between an output value and a reference value; the specific signaling process comprises comparing the sign function sgn(ε) with a preset value ρ after being magnified by a factor of Z0, processing the difference in a 1/s step to obtain a power reference value ps,ref, comparing the power reference value ps,ref with the active power ps to obtain the difference E, and then delivering the difference to the sign function sgn(ε) to form a feedback closed-loop system; third closed-loop feedback for implementing control of rate of change of ωr and in turn for limiting ΔTm within (0,ΔT*m). the specific implementation method comprises comparing the active power ps with the power reference value ps,ref to obtain the difference ε, then delivering the difference to the sign function sgn(ε); on one hand, comparing the sign function sgn(ε) with a preset value ρ after being magnified by a factor of z0, processing the difference in a 1/s step to obtain the power reference value ps,ref, and further comparing with the active power ps to form closed-loop feedback; and on the other hand, magnifying the sign function sgn(ε) by a factor of U to obtain U0/s, and thus obtaining the reference value ωr,ref of the rotating speed, comparing ωr,ref with ωr, processing the difference in a PI proportional differential step to obtain a standard rotor quadrature axis componentωr,reft=iqr*,and then further comparing with a preset value iqr to determine a reasonable upper limit Δω*r, thereby implementing control of the rate of change of ωr and in turn limiting ΔTm within (0,ΔT*m).