The Research Of Control Technologies For SPWM Single Phase Grid-connected Inverter Of Microgird

Energy crisis and environmental pollution problems accelerate the renewable energyresearch and development. The new distributed power sources such as solar photovoltaiccells, wind turbines and fuel cells and other renewable energy constitutes an importantmicro-grid distributed power, distributed generation in the form of energy can be achievedgeographical complementarity and optimal allocation of resources. These distributedpower subject to a fixed interface device connected to the grid, to the remote load, ordirectly to the use of an inverter to convert the local AC load power supply, so no matterwhat kind of power will go through the form of grid-connected inverter converts. Drivenby the rapid development of modern electronic technology and information, science andtechnology continue to progress. high-tech products and electrical equipment for powerquality make increasingly stringent requirements, so superior performance, full-featured,high reliability grid inverter has become the subject of great concern.In this paper, the work will be done in the following aspects:(1) The phase grid-connected inverter control technology is based on the SPWMTMS320F28335. Construction of the micro-grid model and inverter simulation model toanalyze the basic concepts of the principle of SPWM inverter, modulation andphase-locked loop. The establishment of a micro-grid system simulation model is inMatlab/Simulink simulation environment, the simulation results show that the applicationof phase-locked loop technology, the system completes the inverter current and the gridvoltage lock-in0.17s. Followed by selection and design of the LC filter circuit of theinverter circuit device.(2) Studing the topology of the network and the main circuit of the inverter, theworking principle of the system is analyzed to determine the control strategy of the system.DSP hardware design introduced from minimum system circuit, the signal acquisitionmodule, IGBT power module, human-computer interaction module, communication module; software design introduced the program, system clock design, implementationSPWM symmetry regular sampling method, CAP achieve phase-locked loop functions.(3) To the inverter SPWM wave and current test object, the establishment of asingle-phase grid-connected inverter system are studied grid voltage waveform qualityconversion, SPWM dead zone settings, the carrier is not the same than the SPWMwaveform and grid voltage and you get phase lock signal. Experimental results andcomparative analysis of the results shows that the design theory: The application ofsymmetry regular sampling method can get good quality waveform SPWM wave; invertersinusoidal signal frequency is50Hz, sinusoidal signal with the grid voltage signalcompletion of lock-in, phase-locked frequency error2.5%, within the allowable fluctuationrange; single-phase SPWM inverter control system and reasonable structure design, stableoperation, to verify the legitimacy and effectiveness of the program.