Integrated PFC and DC DC converter for dual DC bus for online UPS application

A non-transitory computer-readable medium containing thereon computer-executable instructions for controlling an uninterruptible power supply (UPS) having an AC input configured to receive AC power, a DC input configured to receive DC power, a converter including a common connection point, a first rail coupled to the common connection point, a second rail coupled to the common connection point, a first capacitor coupled between the first rail and ground, a second capacitor coupled between ground and the second rail, a first switch coupled to the DC input and the second rail, a second switch coupled between the common connection point and ground, and a third switch coupled to the common connection point, the AC input, the second rail, the instructions instructing at least one processor to:

• operate the UPS in an AC power mode responsive to the AC input receiving the AC power;
• operate the UPS in a DC power mode responsive to the DC input receiving the DC power;
• and
• based on whether the UPS is operating in the AC power mode or the DC power mode:
• operate the first switch to selectively control a connection between the DC input and the second rail;
• operate the second switch to selectively control a connection between the common connection point and ground;
• and
• operate the third switch to selectively control a connection between the common connection point and the second rail and selectively control a connection between the common connection point and the AC input.

A method of controlling an uninterruptible power supply (UPS) comprising:

• in an AC power mode of operation:
• coupling a common connection point and an AC input together via an input selection switch, the common connection point being further coupled to a first rail and a second rail;
• coupling the AC input and the common connection point to ground via a first switch;
• decoupling the AC input and the common connection point from ground via the first switch;
• and
• decoupling a DC input from the second rail using a second switch;
• in a DC mode of operation:
• coupling the second rail to the common connection point via the input selection switch;
• coupling the DC input to the second rail via the second switch;
• decoupling the DC input from the second rail via the second switch;
• coupling the common connection point to ground via the first switch;
• and
• decoupling the common connection point from ground via the first switch;
• and
• providing DC power to the first rail and the second rail.