A study on charge patterns for uninterruptible power supply system with distributed generators

We have developed an uninterruptible power supply system (UPS) with distributed generators (DGs) and started field testing with to reduce environmental effects and increase local energy production for local consumption. The purpose of this system is to supply the power without connecting to the utility gird. The DGs consist of photovoltaic (PV) -and wind generators (WG), and the main energy source of this system is the DGs and the UPS battery. When the system does not get enough energy from the DGs, and the power supply of the battery runs out, this system connects to the utility grid and begins to charge the battery and supply to the load. We focused on the receiving power from the utility grid and studied ways to reduce the cost of electricity. When this system receives power from the utility grid, most of the power is used to charge the battery. Therefore, we tested several patterns for charging the battery and calculated the cost of electricity based on these test results. As a result, we found that when we reduce the peak power and extend the charge times, the cost of electricity is reduced.