Resarch On Coordinated Control Of DC Micro Grid Scenery Storage

Under the dual pressures of energy shortage and environmental pollution, grid-connected generation technologybased on renewable energy developed rapidly recently. The photovoltaic, wind power and other distributed generationunit power output is random and intermittent, and the network will have a direct impact on power quality. To take full advantage of DG, micro-grid with a single point of access, operation mode and flexible features came into being, which formed the output of DC micro-grid power, without regard to the frequency and phase, andthe control structure is simple, it can improve the quality of electricity reduce system losses, and its development of obvious advantages, The relatedresearch has certain theoretical significance and engineering value.Firstly, the paper determined the topology of DC micro grid, analyzed the characteristics and advantages of micro-grid, then based on mathematical model of photovoltaic cells, established environmental correction method based on universal simulation model, simulated output characteristics of photovoltaic cells in different light intensity and temperature conditions change, and then adopted perturbation and observation method, by controlling the duty cycle circuit algorithm, built a photovoltaic system control model, simulatedits tracking results. Then it designed a PV system power adjustment controller, so that the system can achieve DC micro-grid power output on demand.Secondly, it analyzed the principle of charging and discharging of the battery and circuit model introduces two-way charging and discharging circuit theory, identified as used herein, battery charge and discharge control strategy, which is in standby mode and network operation, and the islands of the runtime constant voltage charge (discharge) electronically controlled, so that the battery in its setting range, according to the output power and load power relations within the DC micro-grid, on-demand balance by charging and discharging the power to maintain the stability of the bus voltage. Then the paper built the battery discharge simulation model validation by accessing the load capacity of the battery discharge.Thirdly, based on the mathematical model of wind turbine and generator, the paperbuilt decoupled model of its coordinates, simulation analysis of wind turbine output power characteristics. Through the pitch angle, speed, machine side converter control to achieve maximum wind power tracking, and according to the actual operation of DC micro-grid wind turbine designed down power control. Then it established a PMSG simulation model to analyze the working conditions under different wind speeds. Then based on GCC mathematical model, used the d-axis grid voltage oriented vector control, through coordinate transformation, achieved active and reactive power decoupling independent control, established a permanent magnet direct-drive wind power generation systems based on double PWM structure, and accomplished the simulation on connected-grid operation.Finally, the paper established simulation model of scenery storage DC micro-grid system, designed a DC micro-grid energy management and coordination control method based on bus voltage recovery, analyzed the system and network operation at the next grid failure and limiting short-term operation and island operation mode energy management, and coordination of the control method switching conditions in detail, and identified the correctness and feasibility of the control strategy on the model through simulation.