Research On Initiative Harmonic Suppression In Grid Inverter Suitable For Micro-grid

Nowadays we are facing something serious like global energy shortage andenvironment pollution, and the traditional way generating electricity by water and fire isdifficult to meet the need of the human society. In order to solve the problem, the microgrid gradually receives the attention of the world with its own advantages anddevelopment. It could improve the energy efficiency as a whole through the users easilyget to the nearest electricity and heat removal. It also applies the green energy for powergeneration such as wind power and solar energy, and the use of clean energy significantlyreduce the harmful gas emissions, such as CO2, even achieving zero emissions, whichgreatly improve the environment quality. Therefore micro grid system bring a lot ofconvenience to the society, but when the micro inverter connecting to the grid, there arealso bringing some harmonic, and how to control the inverter power grid harmonicinhibition in the system is becoming one most hotspots in nowadays.Based on the research background of micro grid inverter, aimed at harmonicinterference problems, and studied grid inverter, this paper put forward a kind of virtualharmonic impedance method to suppress the harmonic micro grid. By analyzing theserious impact on the power grid, according to the national requirement for micro gridsystem interconnection, it realizes effective suppress the harmonic power grid in parallelat the same time, with three-phase grid inverter as an example, analysis of three-phasegrid inverter grid inverter in micro grid working principle, while the important researchgrid inverter control method to restrain the harmonics. And on the basis of the currentloop and voltage loop adding virtual harmonic impedance ring. UsingMATLAB/SIMULINK simulation software, establish interconnected micro grid system,micro electric power generation by grid inverter is connected to the grid. In the controlcircuit of grid inverter mainly analyzes the working principle an function of virtualimpedance, the instantaneous reactive power theory to extract power grid harmonics,harmonics impedance, voltage, current loop grid inverter driving signal, finally through the sine pulse width modulation method of SPWM inverter control work, the successfulrealization of interconnection grid harmonics at the same time, to do research. In addition,this article dsPIC30F6010as control core, structures, the hardware experimentalplatform，including the control circuit. Driving circuit, and measuring circuit.Simulation results show that the subject based on virtual harmonic impedancemethod can successfully suppress the harmonic power grid, improve power quality, hasguiding effect to actual project, verify the feasibility of the scheme, reached the designrequirements.