Uninterruptible power supply systems and methods supporting high-efficiency bypassed operation with a variably available power source

Abstract

An uninterruptible power supply (UPS) system includes an AC input configured to be coupled to an AC power source, an AC output configured to be coupled to a load, a power conversion circuit comprising a first converter circuit configured to receive power from a variably available power source, a second converter circuit coupled to the AC output, a DC link coupling the first and second converter circuits, and a switching circuit, e.g., a bypass circuit, configured to selectively couple and decouple the AC input and the AC output. The UPS system further includes a control circuit operatively associated with the power conversion circuit and the switching circuit and configured to cause concurrent transfer of power to a load at the AC output from the AC power source and the variably available power source via the switching circuit and the power conversion circuit, respectively.