Research On Grid-connected And LVRT Control Strategy Of Three Phase PV And Energy Storage

When it comes to the grid-connected inverter connected with distribution system in the photovoltaic and energy storage systems, first based on the mathematic modules that are under distribution’s normal condition, analyzing and inverting the controlling strategies. Second, according to power balance theory, developing the coordinated control strategy, whose availability will eventually be verified by simulation, for three-phase grid-connected photovoltaic and energy storage systems with distribution system being in normal condition.As for the invalidation of PLL during the disorder of distribution system, the first thing is comparing pros and cons of several different PLL controlling strategies, then yielding the controlling method based on DSC’s advantages in phase lock and the testing of grid voltage’s positive sequence component. Second, on account of the mathematic module of grid connected inverter with distribution system failed, drawing the controlling strategy for grid connected inverter. With the goal to repress the negative sequence component of grid current, this strategy could limit the amplitude of grid current, and provide reactive power compensation. Finally, this strategy’s feasibility will be verified by the simulations when distribution system has symmetrical fault and asymmetrical fault.Developing the experiment platform for three-phase grid-connected photovoltaic and energy storage systems based on the topology of three-phase grid-connected photovoltaic and energy storage systems. First, carry on the design of the system main circuit parameters and the hardware and software controlling system. Second, make sampling calibration and PLL testing for platform, at the same time, by having grid-connected experiment in terms of unity power factor for grid connected inverter and the testing for the dispatch for three-phase grid-connected photovoltaic and energy storage systems, the dispatching ability of this system when distribution system works can be identified. Finally, implementing the low voltage ride through experiment for this system with the disorder of distribution system to demonstrate that this system is capable of low voltage ride through when distribution system is failing.