Application And Research Of DC Active Power Filter In DC Micrgrid

With the rapid economic development,traditional fossil energy sources are drying up,and the research and utilization of renewable energy sources have been put on the agenda.Among them,the technology of using solar power is becoming more and more perfect,and this technology has been applied in many fields.Natural factors such as light intensity and temperature in solar power generation have a great influence on the photovoltaic battery pack,which will cause intermittent input.There are a large number of converters and non-linear load elements in the independent photovoltaic DC microgrid,which will generate a large amount of ripple.These factors have seriously affected the power quality of the DC microgrid.This paper introduces the structure of three kinds of DC microgrids in detail.Through comparative analysis of these three kinds of DC microgrids,the radial microstructures are selected.In the built DC micro-grid,each unit module and basic control method are introduced.Then,a simulation model of DC microgrid was built by MATLAB /SIMULINK.The simulation results show that the built DC microgrid simulation model generates a lot of ripples,and finally the causes of ripples are analyzed.Aiming at the ripple problem generated by the above-mentioned DC microgrid,this paper uses a DC active filter to suppress the ripple in the photovoltaic DC microgrid.First,a DC active filter(DC-APF)with a single-phase inverter as the main circuit is studied and this structure is relatively simple and the cost is low.In this paper,the DC active filters in PI,fuzzy PI,and fuzzy PI-repetitive control modes are analyzed separately,and the compensation effect of this structure of DC active filters is observed through simulation.The simulation verifies the feasibility of the DC active filter of this structure and the control strategy adopted.Secondly,a single-phase Boost DC active filter is proposed.Compared with the traditional DC active filter,it does not need to detect the load current and does not need to separate the ripple current in the load current.Therefore,the high-precision multiplier is omitted,and the control circuit is simple.The structure topology and working principle of the DC active filter are introduced in detail,and the integral sliding mode control method is adopted for the DC active filter of this structure.The feasibility is verified through the establishment of simulation.Finally,the DC active filters of the above two structures are applied to theconstructed DC microgrid simulation model,and the effects of the DC active filters of the two structures on suppressing ripple is observed.