Reseachonmarching-on In-timescheme And The Fastalgorithm Of Time Domain Integral Equation

With the exhaustion of conventional energy sources, countries in the world began to focus on distributed generation. Due to the uncontrollability and randomness of distributed generations, the negative impact on the stability of the power system is increased with the increase of the permeability of the distributed generation. In order to take full advantage of the renewable energy sources and give an effective management to the distributed generation unit, the micro grid structure came into being. Micro grid has two typical running modes: grid-connected mode and islanded mode. When Micro grid operates on grid-connected mode, the frequency is controlled by the main grid; When Micro grid operates on islanded mode, the Micro grid can only rely on themselves to maintain the frequency stability. The unpredictability of load and the intermittent and volatility of the wind power makes the control of the frequency more difficult, so it is necessary to have research on the frequency control of the wind-diesel-battery hybrid power system when the Micro grid operates on islanded mode.This thesis proposed a frequency control method of wind-diesel-battery hybrid power system which is based on load and wind power forecast information. The main research works are carried out as follows:1、The structure of the wind-diesel-battery hybrid power system and the operating characteristics of the major components of wind-diesel-battery hybrid power system were studied, then display the principle and control structure of the frequency control method of wind-diesel-battery hybrid power system which is based on load forecast information. The control structure consists of two parts: load forecasting based wind-diesel distribution module and real-time control of energy storage battery module.2、In order to reduce the wind power and load fluctuations? affections on the frequency control of the system and take full advantage of load and wind power forecast information, the paper designs a wind-diesel power distribution module, according to the difference between the predictive value and the actual value of wind turbines and diesel, the paper designs a fuzzy controller to amend the allocated power value of wind turbine and diesel engine. By reducing the possible active power difference between the supply and demand, thus reducing the frequency fluctuations of the micro grid that may occur. The proposed allocation strategy of wind-diesel power system was simulated by MATLAB, the result indicates that the control strategy proposed in this paper is more effective compared to the control strategy without using the load and wind turbine forecast information.3、Because of the error between the predicted data and the actual data,the battery energy storage system is used to control the frequency of micro grid. However, the droop coefficient of the traditional droop-control strategy is hard to adjust and the system has steady state error and poor anti-jamming capability, it is necessary to improve it. Real time frequency compensation controller is designed based on the Extended State Observer in this paper. The load and wind power fluctuations was considered as an disturbance on the system,the transfer function of battery and micro-grid plant is converted to state space representation, as a controlled object of ADRC(Active Disturbance Rejection Controller),by adjusting the controller parameters to make the frequency Fluctuations around the rated frequency. The proposed real time control strategy of battery storage system based on ARDC was simulated by MATLAB, the result indicates that the control strategy proposed in this paper is more effective compared to the traditional droop-control strategy of the battery storage system.