Micro-grid Interconnection Control Research Based On Adaptive Genetic Algorithm

With the intensification of environmental friendly and energy demand contradiction, distributed clean energy, micro power grid structure have strong investment actively promote international customers and applications. However, due to a variety of distributed micro power batch access, brought to the main power grid unstable and uncontrollable factors limit its development, micro grid technology can be a good solution to this problem. Micro grid unit has run two kinds of operation modes:grid coordinate and island autonomy operation commonly. Micro grid unit USES the master-slave control strategy, and the main distribution network coordination of parallel operation, all the micro power to take control of constant power control (PQ); Island autonomous operation, the main power supply with constant pressure fixed frequency control (V/f control), for supply the voltage and frequency reference signal from the main power, and the slave power supply still uses the constant power control. The main topics studied in photovoltaics, wind turbines and battery energy storage for distributed micro-power micro-grid, the inverter controller design and parameter optimization.The mainly research work completed includes:1. Research on the photovoltaic power generation system and the wind turbine model, choose the battery as energy storage device, describes the characteristics and the functional expression of these models.2. Illustrates the design steps of interconnection of three-phase inverter controller. In the three-phase inverter grid study, elaborated the principle of constant power control strategy and design methods, and discusses current loop adaptive design and phase-locked loop design.3. Designed a three-phase inverter and network controller. Discuss the micro grid controller unit and strategy, design of the controller with adaptive functions. Distributed micro grid connected power supply and main distribution by inverter, use the voltage source inverter, Change the amplitude and phase to control the inverter output power. Micro power grid connected operation requirements of all the parameters following the main distribution network, The main distribution network provides reference value, such as voltage and frequency results show that the controller has worked well in maintaining the stable operation of the grid.4. Apply the genetic algorithm on grid controller parameters optimization. Refer to micro grid parallel operation conditions, clear decisions and constraints. According to the micro-grid distributed power type, operation mode and other parameters, equipped with reasonable weights of building objective function. Then evolutionary operation such as selection, crossover and mutation, finally it is concluded that the optimal solution, and save the corresponding controller parameter values.5. The controller designed in this thesis is compared with simulation. First introduced the experimental system and the control parameters, choose the optimized controller parameters directly, then respectively set up circuit, open circuit fault analysis, analysis of dynamic characteristics of the controller, also set up a dynamic which the controller given, the following discussion. The simulation results verify the effectiveness of the proposed control strategy, and the excellent after optimization.