Research On Control Strategy Based On Distributed Power Microgrid

Today's power consumption is rapidly developing and the power grid structure is diversified.Higher requirements are placed on the safety and reliability of the load,and the power is more stable.The research on distributed power supply has greatly alleviated the tension of power supply in China,but how to improve the reliability of power supply and the safety of power grid has become an urgent problem to be solved.Different distributed power sources are connected to the power grid.Whether it is different in terms of operation mode and grid-connected parameters,it is necessary to select an appropriate control strategy so that it can not only meet its own operational requirements,but also ensure that it can also be integrated into a microgrid.Make the entire system stable.This paper starts with the characteristics of distributed power model of micro-burning steam turbine power generation system,wind power generation system and photovoltaic power generation system,and studies the control of micro-grid and distributed power inverter composed of multiple distributed power sources with distributed power supply coordinated control as the core.Strategy.Ensure that the distributed power supply meets the grid connection conditions and maintains the stability of the entire system.Firstly,the domestic and international research status of the microgrid is explained,and the operation modes and characteristics of several common distributed power sources are analyzed in detail.It is pointed out that the operation mode of the microgrid is divided into two forms: island operation and grid connection operation.The main control methods of microgrid operation are analyzed in detail.Then,the micro-combustion steam turbine power generation system is studied,and its modeling and grid-connected strategy control are analyzed.(1)For the micro-combustion turbine,the speed control,temperature control and fuel control are analyzed under the basic VF and PQ control strategy strategies.The three control are optimized and the micro-burning turbine model is established.Inverters,rectifiers,microturbines,and synchronous generators are used to analyze their control strategies and simulate modeling.(2)Simplified the equivalent circuit of photovoltaic cells,on the basis of which the mathematical model of photovoltaic cells was designed.Based on the analysis of the MPPT algorithm,the algorithm is improved to keep the output power of the photovoltaic cell in the maximum state.The adaptive MPPT control strategy of the solar cell is designed and combined with the voltage control to complete the conversion of DC and AC while performing maximum power point tracking.(3)The mathematical model of wind turbine generator and generator in permanent magnet direct drive wind power generation system is determined in wind power generation system,and the machine side control strategy and grid side control strategy are studied.Zero-axis current-conversion control is adopted on the machine side,and direct current control is adopted on the mesh side.Then a grid-connected inverter control strategy based on proportional resonance control is proposed.The grid side control uses a voltage outer loop to manipulate the transmission of the DC main circuit voltage.The current inner loop controls the active and reactive power of the grid.The traditional PI control requires complicated coordinate transformation and inverse transformation.Therefore,a grid-connected inverter grid-connected strategy based on proportional resonance control is proposed and compared with the traditional grid-connected strategy.(4)Simulation of three micro-power generation systems using Matlab/Simlink,the results show that the model has good dynamic performance.Finally,a microgrid model with three kinds of micro power supplies is built.The microgrid is controlled by PQ control,and the dynamic performance of the microgrid is simulated when the dynamic environment,the operating mode is changed and the off-grid state is completed.The developed control strategy can better maintain the stable operation of the entire microgrid system.