Research On The Control Strategy Of The Grid-connected Inverter With Harmonic Suppression

Based on the traditional grid inverter, the harmonic suppression function is added inthis paper. It makes the inverter compensate the grid harmonic to achieve the aim ofharmonic suppression while the inverter sends active power to grid. From the inverterproceeding in the paper, it analyzes it’s working principle and studies it’s control strategy.On this basis, the harmonic suppression is added. And in the view of reducing harmonicdistortion in transmission line, it is added a synthetic harmonic wave impedance method.Firstly, it introduces the basic principles of single-phase and three-phase grid inverter.Starting from the principle analysis of how to keep the inverter output power factor to be1,it makes theoretical foundation for the following control method to inverter. Secondly, itcontrasts and analyzes the various control methods for grid inverter such as open loopcontrol, average voltage feedback control, voltage instantaneous value control, currentinstantaneous value feedback control, voltage current double loop feedback control method,the voltage space vector method and the advantages and disadvantages of each method.And finally it selects voltage current double loop feedback control method.Again, it introduces and analyzes the synthesis of harmonic impedance method. Thismethod can reduce the resonance distortion of inverter output wave in the transmissionlines. It introduces the concept of synthesis harmonic impedance in principle. It derives thetransfer function of system according to the equivalent circuit, gives the inverter outputimpedance potter diagram and validates the feasibility of this method in theory.Finally, it makes the simulation analysis for the entire system based onmatlab/simulink including active transmission simulation, only alone harmonicsuppression function simulation, both harmonic suppression and the active transmissionsimulation, adding synthetic harmonic impedance method simulation. It gets the correlativesimulation waveforms and verifies the method in the paper correct.