Robust Variable-Pitch Control Design of PMSG Via Perturbation Observer

Wind turbine employs pitch angle control to maintain captured power at its rated value when the wind speed is higher than rated value.This work adopts a perturbation observer based sliding-mode control(POSMC)strategy to realize robust variable-pitch control of permanent magnet synchronous generator(PMSG).POSMC combines system nonlinearities,parametric uncertainties,unmodelled dynamics,and time-varying external disturbances into a perturbation,which aims to estimate the perturbation via a perturbation observer without an accurate system model.Subsequently,sliding mode control(SMC)is designed to completely compensate perturbation estimation in real-time for the sake of achieving a global consistent control performance and improving system robustness under complicated environments.Simulation results indicate that,compared with vector control(VC),feedback linearization control(FLC),and nonlinear adaptive control(NAC),POSMC has the best control performance in ramp wind and random wind and the highest robustness in terms of parameter uncertainty.Specially,the integral absolute error index of!m of POSMC is only 11.69%,12.10%and 15.14%of that of VC,FLC and NAC in random wind speed.

Experimental investigation on indoor daylight environment of building with Cadmium Telluride photovoltaic window

Photovoltaic(PV)windows have received more and more attention in recent years since their active energy-saving advantages.Considering the surface covered with solar cell modules,the indoor daylight environment of PV windows is obviously different with clear glass windows.However,despite many scholars have studied the indoor daylight environment of PV windows,there few investigations study it from the perspective of human subjective visual perception.In this paper,the indoor daylight environment and human visual comfort of building with Cadmium Telluride Photovoltaic(CdTe-PV)window were investigated.Firstly,the parameters of indoor daylight environment and subjective questionnaires in rooms with CdTe-PV window and clear glass window were analyzed respectively.On the basis of this,combined with indoor working surface illuminance and results of subjective questionnaires,the daylight illuminance threshold of human visual comfort was investigated by the method of Mean Bias Degree(MBD).Finally,an evaluation model for indoor daylight environment of buildings with CdTe-PV window was developed by Fuzzy Comprehensive Evaluation Method.The results showed that the working surface illuminance of CdTe-PV window was lower than that of clear glass room,the CCT of different windows room had a minor gap and the CdTe-PV window room was closer to the recommended range that was 3300-5000K.As for CRI,both the CdTe-PV window room and the clear glass room could meet the visual comfort requirements of office staff.Furthermore,it was found that the requirement of human visual comfort was met when indoor working surface illuminance varies between 500-2200lx in the room with CdTe-PV window.At last,according to the comprehensive evaluation model proposed in this paper,it was found that the indoor daylight environment of buildings with CdTe-PV window was excellent in the present experiment.