Research On Integrated Control Strategy Of Micro Grid Voltage Quality

With the gradual depletion of global fossil energy and environmental pollution,in order to ease the energy crisis and protect the ecological environment of the earth,it is imperative to replace the traditional fossil fuel power generation with renewable clean energy generation.At present,the main renewable alternative energy sources,including solar energy,wind energy,water energy,biomass energy,including photovoltaic power generation,wind power generation has been rapid development in recent years.Photovoltaic power generation,wind power in addition to large photovoltaic power plants,wind farms,a large number of photovoltaic,wind power access to the distribution network using micro grid.Because of the fluctuation of the distributed generation,the randomness of the local load and the interaction of the inverter,the voltage quality of the microgrid has some problems.With the user requirements on power quality improvement of micro network voltage quality problem is more and more and more research attention in power supply enterprises,new and more suitable compensation measures and control strategies to improve the quality of voltage level of microgrid grid,has very important significance.Based on the existing typical microgrid structure,operation mode,main power supply and distributed control strategy based on the established model of microgrid system,micro grid voltage harmonics and unbalance are analyzed,put forward the integrated control strategy of inverter based on multi function interface.The main work is as follows:First of all,first of all,according to the harmonic problems in the microgrid,combined with the method of harmonic detection based on instantaneous power theory of nondestructive,combined with micro interface inverter control network,this paper proposes a multi.function interface inverter,but because of the traditional proportional integral(PI)controller can not the sine wave type zero static error,proportional resonant(PR)controller is also difficult to be used in practice,combined with the traditional PI controller and PR controller,the proportional integral resonant(PIR)controller is used to control the inner interface inverter.Secondly,aiming at the unbalanced problems,mainly analyzes the network interface of micro inverter under unbalanced grid voltage mathematical model and output characteristics under the condition,this paper proposes a multi.function inverterinterface,superposed on the basis of constant power control of the feedforward negative sequence voltage control measures.Finally,the DIGSILENT/Power simulation software is used to build the model of the two kinds of multi.function inverter.The results show that the above voltage quality control measures can be applied to the microgrid environment,and can effectively improve the voltage quality in the microgrid while ensuring the constant power control of the inverter.The multifunctional inverter control strategy to suppress the harmonic or three.phase voltage imbalance,the comparison method of power electronic device installation and tradition,not only can reduce the cost and maintenance cost,but also avoid the installation of power electronic device to microgrid to inject new harmonics at the same time.