Apparatus and methods for coordinated static switch operations for load transfers in uninterruptible power supply systems

An apparatus for controlling load transfers in a power supply system including an uninterruptible power supply (UPS) having an input configured to be coupled to a first power supply and an output configured to be coupled to a load, a first static switch controllable to provide a switchable bypass path between the first power source and the load and a second static switch controllable to provide a switchable path between the load and a second power source other than the UPS, the apparatus comprising:

• a controller circuit configured to cooperatively control the first and second static switches to transfer a load coupled to the output of the UPS to the second power source,
• wherein the controller circuit is operative to transition the load from a first state wherein the load receives power from the first power source via the first static switch to a second state wherein the load receives power from the second power source while isolated from the first power source, and
• wherein the UPS comprises a first UPS having an output configured to be coupled to a first load, wherein the power supply system further includes a second UPS having an input configured to be coupled to the second power source and an input configured to be coupled to a second load and a third static switch controllable to provide a switchable bypass path between the second power source and the second load, wherein the controller circuit is further configured to control the first and second static switches to transition the load from the first state to the second state, wherein the load in the second state receives power from the second power source via the UPS and/or the third static switch while isolated from the first power source.

A method of operating a power supply apparatus that includes an uninterruptible power supply (UPS) having an input configured to be coupled to a first power source and an output configured to be coupled to a load, a static switch controllable to provide a switchable bypass path between the first power source and the load, and a second static switch controllable to provide a switchable path between the load and a second power source other than the UPS, the method comprising:

• cooperatively controlling the first and second static switches to transfer the load to the second power source,
• wherein cooperatively controlling the first and second static switches to transfer the load to the second power source comprises controlling the first and second static switches to transition the load from a first state wherein the load receives power from the first power source via the first static switch to a second state wherein the load receives power from the second power source while isolated from the first power source, and
• wherein the UPS comprises a first UPS having an output configured to be coupled to a first load, wherein the power supply system further includes a second UPS having an input configured to be coupled to the second power source and an output configured to be coupled to a second load and a third static switch controllable to provide a switchable bypass path between the second power source and the second load, and wherein controlling the first and second static switches to transition the load from a first state wherein the load receives power from the first power source via the first static switch to a second state wherein the load receives power from the second power source while isolated from the first power source comprises controlling the first and second static switches to transition the load from the first state to the second state, wherein the load in the second state receives power from the second power source via the second UPS and/or the third static switch while isolated from the first power source.