Coordinated Control Strategy Of Active Power In Multi Inverter Of Photovoltaic Power Station

With the development and progress of human society,the problem of energy shortage is becoming more and more serious.Photovoltaic power generation using photovoltaic effect provides a sustainable way to solve the energy problem..However,with the increase of the permeability of photovoltaic power generation,the inherent intermittent and volatility characteristics of the power system will have more and more influence on the stability of the power system.So the national grid to develop relevant technical standards for photovoltaic power plants to regulate the grid,which request the grid connected photovoltaic power plant output power and power change rate meetting the requirements of the dispatch instructions.Taking into account the photovoltaic power plant PV inverter may come from different manufacturers,in the acceptance of power conditioning tasks,the time of photovoltaic inverter to complete the adjustment will be different,and in order to ensure the power supply reliability and operation stability of power system,and the economic benefits of photovoltaic power station,this paper studies the active power coordination control strategy of multi inverter in PV power station.Firstly,this paper carries on research and analysis of grid connected photovoltaic power generation system,the working principle of photovoltaic array and inverter structure,theoretical analysis and simulation study of the relationship between the output power and photovoltaic power plant changes with the grid frequency offset,and points out the necessity of the active power control of photovoltaic power station.The influence of different adjustment characteristics of the inverter on the active power control and grid operation of PV power station was studied by analysing the active power control process of PV power plant with centralized inverter and the insufficient of the current power allocation strategy widely used,pointing out that the different regulation characteristics of the inverter should be considered in the design of active power control strategy.Secondly,according to the active power change rate limit,put forward the flow of active power change rate limit on the basis of the definition of change rate.To reduce the amount of data in active power control,select a model inverter,whose output power range is the reference standard of the other inverters.Design an average allocation strategy taking the sample inverter into accont for the situation that inverters has same regulation characteristic;another strtegy is put forward for the situation that inverters has vary different regulation characteristic,letting the output power of the photovoltaic power station can be quickly and accurately meet the expected output power,while retaining and improving the photovoltaic power plant capacity by using inverters with fast regulating speed and Power balance method.Finally,build the model of grid connected photovoltaic power generation system to simulate the power control strategy.The simulation results show that the active power control strategy can quickly and accurately track the active power,and meet the target.