Research On Control And Operation Optimization Of Microgrid Based On Distributed Generation

In recent years, the worldwide energy and environmental problems become more and more serious; as the demand for electricity increases, the traditional centralized power grid has already exposed some disadvantages, and the development of microgrid system based on new energy distributed generation is an important method to solve the above problems. This paper is concerned of the research on microgrid control based on distributed generation and operation optimization. The microgrid structure which suitable for a variety of new energy distributed generation has been proposed, the system simulation model was established and the grid-connected inverter and microgrid operation control strategy were discussed. On this basis, the optimization research on optimal energy utilization method of DC bus in microgrid system, compensation method of the grid harmonic and the island detection method has been done, and the operation effect of microgrid system has been increased effectively. According to the development trend of microgrid and smart grid, the intelligent control system includes bidirectional power flow analysis and energy management has been designed, the informatization and intelligent level of the microgrid has been improved. Finally, a smart microgrid system experimental platform has been built and achieved good results. The main work of this paper is as following:1、The microgrid system structure analysis and modelingFor microgrid systems with small and medium-sized power level, a DC bus and communication bus structure has been put forward. According to the model of each part in microgrid system, the simulation model on Matlab/simulink platform has been built.2、The control strategy of distributed power in microgridPut forward the control method of DC/DC converter, DC/AC converter, microgrid operation and the circulation suppression method under the condition of parallel inverter. Especially proposed new design method of low harmonic SVPWM modulation dead zone time injection of DC/AC converter and anti-interference digital phase locked loop.3、The optimal energy utilization method of DC busThrough the analysis on output characteristics of two kinds of micro source:the photovoltaic battery and wind generator used in DC bus, a maximum power tracking algorithm with widely applicability and the coordinated control strategy to ensure the optimal utilization of the overall energy produced by the DC bus has been proposed.4、Harmonic compensation method of distributed generation in microgridBy analysing the harmonic source of microgrid, according to the harmonic compensation principle of active power filter, a new type of compensation control algorithm has been designed, which compensate the harmonic during the distributed generation connected to the microgrid. By injecting the compensating signal which calculated by harmonic compensation controller to inverter modulation wave, distributed power grid and harmonic compensation can be realized at the same, the quality of energy produced by the micronet system can be improved.5、Islanding detection method based on the third harmonic disturbancesAs the traditional island detection method has the disadvantages of high output harmonic content and large detection blind area, by using the harmonic compensation algorithm, an islanding detection method based on the third harmonic disturbances was proposed. This method has the advantage of shorter response time, easier harmonic disturbance control and less harmonic pollution.6、Designed a intelligent control platform of bidirectional power flow analysis and energy managementFor microgrid system, an intelligent control platform based on Android system has been designed, by the result of analisis of the bidirectional power flow in microgrid, the users can decide to buy or sell the electric energy. With this platform, user comfort and the overall efficiency of management can be improved. The intelligent platform structures, bi-directional power flow calculation method and energy management control strategies have been discussed.7、Built microgrid system experimental platformDistributed generation experimental platform based on DSP+FPGA controller including simulation wind generator, solar array, electronic load, simulation microgrid has been built, together with the photovoltaic demonstration power station and public power grid interface, the whole microgrid system control can be realized.