Research On Three-phase Photovoltaic Grid-connected Inverter With Active Filtering Function

The consumption demand for energy in human society is constantly increasing with the progress of science and technology.Photovoltaic power generation system uses green and clean solar energy to generate electricity,which can effectively alleviate the energy crisis,reduce environmental pollution,and has become a necessary choice for sustainable development.However,due to the influence of external environment changes,the output characteristic curve of photovoltaic grid-connected power generation system shows multiple peaks,resulting in very low actual utilization rate;meanwhile,the nonlinear load in the grid will produce harmonics and reduce the power quality.This paper will combine photovoltaic power generation system and active power filter,on the photovoltaic power generation system,add the active filter in the system tracking technology and contains the source filter function of three-phase grid inverter two key problems analysis and study,realize grid power generation at the same time for harmonic governance,improve the level of system operation.In practical application,the system’s photovoltaic array is susceptible to the external environment,making the power-voltage output characteristic curve produce multiple peak phenomenon.In this case,the traditional maximum power tracking method can easily fall into the local maximum power and miss the actual maximum power,resulting in the output power loss.In view of the optimal solution of the traditional maximum power tracking method,this paper improves the incremental method based on the niche technique.This technology sets the multi-peak output characteristic curve as independent niche peaks,and conducts maximum power point tracking in each niche to find extreme values.Using the elite retention strategy to select the maximum value from all extreme values is the global optimal solution,and the effectiveness of the improved method is verified through the simulation platform.Through the simulation results,the method can well avoid the disadvantages of the traditional conductance increment method cannot seek the maximum power point,with dynamic reliability and dynamic,and simple structure principle,can ensure the global maximum power point tracking,maximize output power,and avoid power loss.compensation.According to the load current characteristics and the minimum mean difference algorithm,the harmonic current is used to improve the detection method to detect the system quickly and accurately.In the command current tracking link,adopt the voltage current double closed loop control strategy,use PI controller to stabilize the DC side voltage and provide active command current for the current inner loop control link.The quasi-PR control multiple algorithm is used to accurately track the fundamental wave components and the main subharmonic components to achieve the unified control purpose.Finally,on the Matlab / Simulink simulation platform with three-phase source filter inverter system simulation model,let the system run in full photovoltaic grid,only harmonic governance and photovoltaic grid and active filter unified control three different working mode and simulation verification,the simulation results show that the proposed unified control strategy is good,can meet the requirements of three different working state,effectively improve the system utilization of harmonic governance.