Control of Energy Storage System Inverter System in a Microgrid Application

摘要

A system that manages a supplemental energy source connected to a power grid uses a two stage control strategy to manage power transfers in and out of the power grid as well as in and out of an energy storage system, such as a battery bank. One stage uses a non-linear transfer function to control an output frequency of a DC-to-AC inverter to limit undesired effects of power transients that occur on the grid. A second stage uses control strategy for transferring energy between the energy storage system and an internal DC link based on a relationship between a voltage on a DC link connecting the first and second stages and a DC link reference voltage, the voltage on the DC link, and a voltage at the energy storage system. The control strategy includes rapid charging, over-charging protection, and grid transient stabilization.

主权项

1. A system for managing power transfer with a power grid comprising:
a direct current (DC) link; an energy storage system (ESS) that stores DC power; an energy storage controller coupled between the DC link and the ESS that manages power flow between the ESS and the DC link; and a load controller coupled between the DC link and the power grid, the load controller including a DC-to-AC inverter, the load controller operable to adjust an output frequency of the DC-to-AC inverter using a non-linear power-frequency curve responsive to both a state of a frequency of the power grid and a power transfer state of the load controller.