Research On Coordinated Control Strategy Of PV Battery-energy Storage Hybrid Power System For Black Start

In order to study the black starting capacity of PV battery-energy storage hybrid power system,this paper simulates the process of black start through the method of starting the asynchronous motor for electric power plant.First of all,the mathematical model and principle of photovoltaic and energy storage battery are analyzed in detail in this paper.PV battery-energy storage hybrid power system is established,and the model and principle of its cell structure are analyzed.On this basis,the active power and reactive power control of PV battery-energy storage hybrid power system during black start-up are studied.Considering the failure of black start due to insufficient charge capacity,this paper proposes a new method combining load tracking and MPPT based on the conventional MPPT algorithm.The control strategy can effectively control the PV output,which makes PV system effectively tracking the change of load when photovoltaic has sufficient output,thus no surplus power charges to energy storage;the PV system can track maximum output power and supply for the load together with energy storage when photovoltaic has insufficient output,thereby reducing the capacity of energy storage and providing protection for the success of black start.Then,the control targets of PV subsystem and energy storage subsystem under black start condition are defined,and the subsystems of PV control and energy storage control are established.The front stage DC/DC converter of PV subsystem utilizes maximum power tracking / load tracking control.The after stage DC/AC inverter utilizes dual-loop control to keep the DC bus voltage stable and supply the power to the system load,which doesn’t participate in system frequency modulation.The front stage bi-directional DC/DC converter of energy storage subsystem utilizes DC bus voltage control to control the charge and discharge of energy storage.The after stage DC/AC inverter utilizes constant voltage constant voltage control to stabilize the fluctuation of PV system output for the system to provide voltage and frequency support.Finally,the simulation model of PV battery-energy storage hybrid power system is built by using Matlab/Simulink software.Through simulation,the results verifies the feasibility and correctness of the load tracking and MPPT coordinated control strategy proposed in this paper,also verifies the ability to provide black start power for the restoration of large power grids and the fast black start capability of PV battery-energy storage hybrid power system.