Research On The Process Control And Grid-Connected Harmonic Compensation Method Of Wind Power Generation

Wind power is concerned by many countries as a kind of new, clean and reliable energy that stand out from other various renewable energy. The past five years, wind power generation increase with the growth rate of about30%every year. Variable speed&constant frequency (VSCF) wind power technology has improved the drawbacks that the speed must be kept constant with the technology of constant speed&constant frequency (CSCF) so that the output frequency of the stator must be the same as the grid frequency, which allows the rotational speed of the wind turbine to follow the change of wind speed rotation to capture maximum wind energy.Firstly, the wind turbine model is established in this paper, then the basic structure of the PWM converter is given and the control strategy of the grid-side and rotor-side is derived according to the operating principle of the VSCF doubly-fed induction generation (DFIG) wind power system and DFIG mathematical models. In order to obtain the speed information to achieve variable speed constant frequency and capture the maximum power, a new speed sensorless method is pretented in this paper that the stator flux in the m-axis component is taken as the output of the reference model and adjustable model according to the PQ decoupling vector control (VC) strategy. In addition, the Popov super stability theorem is used to design the adaptive law to estimate the real speed. Finally, the result shows the dynamic and static performance of the system by comparing the identified speed and the actual speed.Due to the uncertainty of the wind resource and the fluctuating power caused by the characteristic of the wind turbine operating wind pwer generation, which may affect the grid’s power quality so that the power quality need to be compensated. In this paper, the impact of wind power on power quality is briefly introduced and the main circuit topology of the unified power quality conditioner (UPQC) is analyzed on this basis and then the establishment of mathematical models of UPQC is given out. In this paper, a new kind of double hysteresis is applied in the parallel side and the active disturbance rejection controller (ADRC) controller is designed to change the drawbacks of conventional double hysteresis current control with no action in the inner ring and get more precise compensation. Finally, the chaotic particle swarm optimization algorithm (C-PSO) is also used to optomize the parameters of the ADRC controller. Compared with other current control method, this method improves the utilization ratio of voltage. The simulation results on MATLAB software are presented to verify the anticipated steady-state and dynamic performance of this control strategy.