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Research On Virtual Synchronous Generator Control Of Microgrid Inverter

Posted on:2019-04-20Degree:MasterType:Thesis
Country:ChinaCandidate:Y L WangFull Text:PDF
GTID:2322330569479953Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
The history of human civilization is a history of energy development and utilization.While economic and social development and population increase,the reserves of traditional fossil energy are less and less,and the pollution caused by the consumption of traditional energy is becoming more and more serious.In recent years,wind,light and other new energy power generation has been developing and utilizing more and more because of its natural pollution-free and rich and renewable advantages.The electricity generated by renewable energy is usually made up of microgrid and then connected to the grid.As a hub connecting the distributed generation and distribution network,the multifunctional control of inverter plays an important role in the distributed generation of renewable energy.The inverter is composed of electronic devices,which is characterized by easy control and fast response,but there is a lack of inertia and damping of the traditional synchronous generator.If the control algorithm can be designed to have the output characteristics of the synchronous generator,it can make the grid connected inverter combine the advantages of the two,and will be beneficial to the stability of the distributed generation system.In this paper,we use the control method of Virtual Synchronous Generator(VSG)to improve the interface characteristics of microgrid inverter.This method can not only provide the support for the voltage and frequency of the microgrid,but also increase the inertia buffer and damping effect for the inverter under the load fluctuation,and participate in the regulation of the voltage and frequency of the microgrid.This paper mainly studies the virtual synchronous generator control of microgrid inverter.This paper first introduces the present situation and prospects of the distributed power generation using renewable energy to make use of the form of micro grid,and points out the practical significance of the research in the background of the increasingly prominent shortcomings of the traditional fossil energy.Before introducing the control of virtual synchronous generator,the control strategies of several traditional microgrid inverters are compared,and their advantages and disadvantages and applicable scope are pointed out.According to the mathematical model of traditional synchronous generator,the control structure of VSG is established.The VSG control is divided into active ring and reactive ring based on active power frequency regulation and reactive power voltage regulation,and virtual governor,virtual swing equation control structure and virtual excitation regulator are designed.Through the small signal model and transfer function,the influence of the main circuit parameters,the virtual inertia and the virtual damping on the frequency response characteristic of the output power of the system is analyzed.And the parameters are designed.The system simulation is carried out on the Matlab/Simulink software platform.The simulation model is divided into five parts: the main circuit,the active frequency,the reactive voltage,the virtual impedance and the SVPWM control,and the construction process of the main controller is introduced in detail.The simulation results of the inverter under the VSG control are divided into the output characteristics of the isolated island running charged resistance load and the resistive load,and the output characteristics of the given reference power under the condition of the grid.The frequency output characteristics of the VSG control and droop control under the same load condition are compared,and the virtual inertia and the virtual load are switched on the load.The effect of the pseudo damping on the frequency output characteristics.Finally,based on DSP320F2812 as the control chip,the hardware experimental platform of inverter based on VSG control is developed.The implementation program of control algorithm is written on the platform of CCS3.3.The output waveform of hall,conditioning and zero crossing circuits is verified by the hardware platform and software program.The output waveform of the inverter under the control algorithm is measured after the SVPWM control signal in the school.The experimental results prove the effectiveness of the control method.
Keywords/Search Tags:distributed power supply, microgrid inverter, moment of inertia, damping, virtual synchronous generator
PDF Full Text Request
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