Dynamic Power Quality Optimization Contrlo Of Steam Turbine Super Capacitor Hybrid Power Generation System

In this paper,the power quality problem caused by the unbalance between the load and the dynamic response of the steam turbine is studied.A hybrid generation system of steam turbine and super capacitor is composed of super capacitor energy storage power supply and turbo generator.The dynamic power quality of micro grid is studied when the turbine fails and the load suddenly changes.In this paper,the turbine super capacitor hybrid power generation system is modeled,and the system architecture and instantaneous power flow direction of the hybrid power generation system are given.On this basis,the nonlinear mathematical model of steam turbine power generation system is established,and the nonlinear model error is analyzed by simulation.The simulation structure shows that the model is accurate within the range of power generation frequency error less than 5%.The modeling of super capacitor energy storage power supply includes bidirectional DC / DC converter and dual-mode inverter.Secondly,aiming at the problem of power quality when the turbine generator trips due to fault,the parallel / off grid smooth switching control strategy of supe r capacitor energy storage power supply is proposed.Firstly the control strategies of bidirectional DC / DC converter and dual-mode inverter are given.The phase pre synchronization strategy of planned grid connection is designed,and the simulation results show that the strategy can realize the smooth switching of dual-mode inverter from off grid to grid connection.In view of the phenomenon of voltage shock when the dual-mode inverter is directly switched from grid to off grid,a smooth switching control strategy based on load current feed forward is proposed,and the simulation results show that the strategy can eliminate the voltage shock phenomenon in the switching process and achieve smooth switching.Finally,the dynamic power quality problem of microgrid with abrupt load in hybrid generation system is addressed.The principle of two kinds of noncooperative control and the influence of their key parameters are analyzed.In this paper,the cooperative optimal control of hybrid power generation system based on the recursive logic of turbine output mechanical power under step load and the cooperative optimal control of hybrid power generation system based on the state feedback control are proposed,which achieve the goal of minimizing the capacity of supe r capacitor energy storage power supply.The mechanism of two kinds of cooperative optimal control and their advantages and disadvantages are analyzed,and they are extended to the case of multi type load.Two collaborative optimization methods are simulat ed under rectangular load and slope load.