Research On Droop Control Strategy Of Microgrid Inverter Based On DSP

With the progress and development of our society,people's demand for energy is growing,so the development and use of new energy is imminent.Followed by the rapid development of distributed generation technology,including new energy,people can get it from more channels.The rapid development of micro network provides a good opportunity,in such a situation,people enhance the use of nuclear,solare,wind energy and other clean energy.The key technology is the research on the operation and regulation of the microgrid,and the useful control method can make the microgrid play a more important role.First of all,this paper briefly introduces the background and function of microgrid research,the research status at home and abroad and the basic concept of microgrid.Then,the circuit structure and control method of microgrid are briefly introduced,and the droop control and its characteristics are emphatically analyzed.In the rotating coordinate system,the mathematical model of the inverter is constructed,and the theory of instantaneous reactive power is expounded to obtain the correct power calculation formula.Then,for the voltage and current phase of the fast and accurate tracking,the use of SPLL design.Based on the theory of droop,the droop controller is designed,its parameters are set and the mathematical model is constructed.This paper probes into the shortcomings and deficiencies of the traditional droop.In order to solve the problem that the power can not be shared,the voltage and current double closed loop strategy and the virtual impedance method are adopted.The frequency droop equation based on the Sigmoid function is used to solve the problem of frequency offset.For islanded microgrid simulation on Simulink platform,namely to build a single inverter model and two-parallel-inverters model to simulation,getting the traditional droop and improved droop control under the waveform comparison results which show that the improved waveform type droop control is more excellent in power sharing performance,and improves the frequency offset in a certain range,which tests the effectiveness of the method.Finally,the hardware structure and software design of microgrid inverter system based on TMS320F28335 are briefly introduced.The hardware mainly introduces the designs of main circuit,the drive circuit,sampling circuit and the protection circuit.The software gives the flow chart of the main program,interrupt subroutine and over-current protection.