Grid Connected Resonance Suppression And Equivalent Modeling Of Photovoltaic Multi Inverter

The only way to implement sustainable development is to strictly prevent and control environmental risks,strengthen energy conservation and environmental protection,clean energy,ecological environment and other industries.In recent decades,wind energy,solar energy and other renewable energy have been widely concerned and efficiently used in many countries.However,a large number of power electronic devices are introduced into the new energy grid connected system,and the harmonic resonance problem can not be ignored.The research on equivalent model considering grid connected resonance of multi inverters has become the focus of transient steady-state analysis of power system.Therefore,in this paper,the resonance suppression optimization and multi machine grid equivalent modeling of photovoltaic power station connected to distribution network are studied and analyzed in detail.Firstly,the working principle of photovoltaic array,maximum power point tracking algorithm,inverter control system,filter circuit and parameter setting criteria are discussed,and the detailed electromagnetic transient model of photovoltaic grid connected system is established.Secondly,the Norton equivalent circuit is used to replace the detailed model of the system,and the mathematical model of the current at the parallel point is derived,which is extended to the parallel connection of multiple inverters under the same working condition.The equivalent model is established,and the resonance characteristics of the system are analyzed,and the influencing factors of the resonance point are discussed.Then,the method of filter circuit capacitor series virtual resistance is proposed to suppress resonance,and the virtual resistance value and optimization scheme are determined.In view of the fact that the photovoltaic environment conditions,inverter conversion effect and grid connected line impedance are not completely consistent in practical application,a multi inverter model is established by improving the canopy + K-means clustering algorithm,which takes the photovoltaic array temperature,solar radiation intensity,active power output,filter circuit capacitor series virtual resistance and transmission line equivalent impedance as clustering indexes The model is compared with the single machine equivalent model.Finally,the system simulation analysis based on MATLAB / Simulink verifies the feasibility and effectiveness of the above resonance suppression method and equivalent model.