ARRANGEMENT FOR USING ENERGY STORAGE IN RENEWABLE ENERGY CONVERSION SYSTEMS

Disclosed embodiments include an arrangement for using energy storage devices to support renewable energy conversion system in implementing inertia response and enhancing fault ride-through capability. The arrangement comprising: (a) a plurality of energy storage devices configured to serve as a temporarily place to store and retrieve electrical energy; and (b) an energy storage controller configured for controlling power flow between said plurality of energy storage devices and the DC link of said renewable energy conversion system. Under normal conditions, the charged level of said plurality of energy storage devices is maintained at 45% to 55% of the fully charging level in order to have the ability to both supply and absorb energy. When there is a grid disturbance, power output of said renewable energy conversion system is being changed such that the grid disturbance is stabilized. The required energy for changing output power is either supplied or absorbed directly to said DC link from said plurality of energy storage devices. When there is a grid fault, because the harvested energy cannot be exported into the local grid, it is absorbed into said plurality of energy storage devices. In both cases, power input from the source side converter of said renewable energy conversion system is kept at a constant level, reducing mechanical vibration and power swing, which may be harmful to the whole system.