Tham khảo tài liệu 'fundamental and advanced topics in wind power part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | MPPT Control Methods in Wind Energy Conversion Systems 349 optimum energy. The method has been presented in section . The wind speed estimation method in 19 is based on the theory of support-vector regression SVR . The inputs to the wind-speed estimator are the wind-turbine power and rotational speed. A specified model which relates the inputs to the output is obtained by offline training. Then the wind speed is determined online from the instantaneous inputs. The estimated wind speed is used for MPPT control of SCIG WECS. Power signal feedback In 20 fuzzy logic controller is used to track the maximum power point. The method uses wind speed as the input in order to generate reference power signal. Maximum power output Pmax of the WECS at different wind velocity vw is computed and the data obtained is used to relate Pmax to vw using polynomial curve fit as given by Pmax - 12 The reference power at the rectifier output is computed using the maximum power given by 12 as Pref G RPmax 13 The actual power output of the rectifier Po is compared to the reference power Pref and any mismatch is used by the fuzzy logic controller to change the modulation index M for the grid side converter control. Hill climb search control HCS control of SCIG WECS are presented in 21 22 . In 21 a fuzzy logic based HCS controller for MPPT control is proposed. The block diagram of the fuzzy controller is shown in Fig. 11. In the proposed method the controller using Po as input generates at its output the optimum rotor speed. Further the controller uses rotor speed in order to reduce sensitivity to speed variation. The increments or decrements in output power due to an increment or decrement in speed is estimated. If change in power AP0 is positive with last positive change in speed Arnr indicated in Fig. 11 by LAar puj the search is continued in the same direction. If on the other hand Arnr causes -AP0 the direction of search is reversed. The variables
