Research On Converter Grid-connected Based On Model Of Synchronous Generator

As development and utilization degree of solar, wind and other renewable energyincreasing, distributed power generation causes people more and more attention, andhow to convert the DC produced by renewable energy to AC and transport it to thepower grid become a research hot spot. In order to let the converter reflectsynchronous generator characteristics to the power grid, and implement renewableenergy connecting to the power grid friendly, this paper does some researches on thecontrol of converter based on the model of synchronous generator.Firstly, a mathematical model of synchronous generator is built, and some deepresearches on the converter control method based on model of synchronous generatorhave been done. How to design the controller and its parameters are analyzed in detail,and an example is given. Two grid-connected ways that quasi synchronization way andself-adaptive way are presented, and simulations about them have been done inSimulink. The results show that the converter control method based on model ofsynchronous generator can control the frequency and amplitude of converter outputvoltage to track the frequency and amplitude of grid voltage well, and the twogrid-connected ways can accurate control the converter to connect to the power gridfriendly when the frequency, amplitude and phase of converter output voltage satisfythe grid-connected condition.Secondly, detailed analysis for converters running in parallel is given. In allusionto the deficiency of traditional droop control algorithm, an improved droop controlalgorithm is introduced. The simulation results show that due to fixed droop coefficient,the traditional droop control algorithm is easy to cause excessive droop, while thedroop coefficient of improved droop control algorithm has certain function relationshipwith output power, so when the load change, the improved algorithm is moreconducive to the stability of the entire system.Finally, this paper introduces the structure of photovoltaic power generation system, and does some further researches on photovoltaic array model under partiallyshaded conditions, the most power point tracing and DC bus voltage stability. In viewof synchronverter can realize grid-connected friendly, it is used in grid-connected PVsystem. Model of every link is set up in Simulink, and some system simulations havebeen done. The results show that the synchronverter can realize photovoltaic powergeneration system connect to the power grid well, and can control the powertransported to the power grid.