UPS systems having multiple operation modes and methods of operating same
A power supply system includes an AC input configured to be coupled to an AC source, an AC output configured to be coupled to a load, a UPS having an input coupled to the AC input and an output coupled to the AC output and a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween. The system further includes a controller configured to control the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input. A multi-mode converter may be coupled to a DC link of the UPS and configured to be selectively coupled to a battery and the AC input to respectively support battery conversion and current control at the AC input in respective first and second modes of operation of the UPS.
1. A power supply system comprising:
an AC input configured to be coupled to an AC source;
an AC output configured to be coupled to a load;
a UPS having an input coupled to the AC input and an output coupled to the AC output, wherein the UPS comprises a rectifier having an input coupled to the AC input, an inverter having an output coupled to the AC output, a DC link coupling an output of the rectifier to an input of the inverter, and a battery coupled to the DC link;
a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween; and
a controller configured to control the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input, wherein the controller is configured to operate the UPS as an online UPS by transferring power from the AC input to the AC output via the rectifier and the inverter in a first online UPS operation state and transferring power from the battery to the AC output via the inverter in a second online UPS operation state, and wherein the controller is configured to operate the UPS as a standby UPS by transferring power from the AC input to the AC output via the bypass circuit in a first standby UPS operation state and transferring power from the battery to the AC output via the inverter in a second standby UPS operation state.
2. A method of operating a power supply system including an AC input configured to be coupled to an AC source, an AC output configured to be coupled to a load, a UPS having an input coupled to the AC input and an output coupled to the AC output, and a bypass circuit coupled between the AC input and the AC output and configured to open and close a bypass path therebetween wherein the UPS comprises a rectifier having an input coupled to the AC input, an inverter having an output coupled to the AC output, a DC link coupling an output of the rectifier to an input of the inverter, and a battery coupled to the DC link, the method comprising:
controlling the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input, wherein controlling the UPS and the bypass circuit such that the UPS operates as an online UPS for a first input voltage magnitude condition at the AC input and as a standby UPS for a second input voltage magnitude condition at the AC input comprises:
operating the UPS as an online UPS by transferring power from the AC input to the AC output via the rectifier and the inverter in a first online UPS operation state and transferring power from the battery to the AC output via the inverter in a second online UPS operation state; and
operating the UPS as a standby UPS by transferring power from the AC input to the AC output via the bypass circuit in a first standby UPS operation state and transferring power from the battery to the AC output via the inverter in a second standby UPS operation state.