High efficiency control method for UPS

A non-transitory computer-readable medium storing thereon sequences of computer-executable instructions for operating an Uninterruptible Power Supply (UPS) including an output switch configured to selectively couple a bypass line to an output of the UPS, the sequences of computer-executable instructions including instructions that instruct at least one processor to operate the UPS to:

• receive input AC power at an input of the UPS;
• de-couple, via the output switch, the bypass line from the output;
• in response to de-coupling the bypass line from the output, operate a DC-DC converter to convert DC power having a first voltage level into DC power having a DC bus voltage level;
• provide the DC power having the DC bus voltage level from the DC-DC converter to a DC bus to charge the DC bus to the DC bus voltage level;
• in response to the DC bus being charged, disable the DC-DC converter and couple, via the output switch, the bypass line to the output;
• provide the input AC power to the output via the bypass line;
• convert, with a rectifier, the input AC power on the bypass line into DC power having the DC bus voltage level;
• and
• provide DC power having the DC bus voltage level to the DC bus via the rectifier to maintain the DC bus voltage level.

A method of assembling an Uninterruptible Power Supply (UPS) comprising:

• providing a charger configured to be coupled to an input, the charger configured to receive input AC power via the input and convert the input AC power into DC power having a first voltage level;
• coupling a DC-DC converter to the charger, the DC-DC converter configured to convert the DC power having the first voltage level into DC power having a DC bus voltage level;
• coupling a DC bus to the DC-DC converter, the DC bus configured to receive the DC power having the DC bus voltage level;
• coupling an inverter to the DC bus, the inverter configured to convert the DC power having the DC bus voltage level into the output AC power and provide the output AC power to an output via an output switch;
• coupling a bypass line including a bypass switch between the input and the output switch, the bypass line configured to provide the input AC power to the output via the output switch;
• coupling a rectifier between the bypass line and the DC bus, the rectifier configured to convert the input AC power on the bypass line into DC power having the DC bus voltage level and to provide DC power having the DC bus voltage level to the DC bus;
• and
• coupling a controller to the charger, the DC-DC converter, the inverter, and the bypass switch, the controller configured to operate the UPS in a first mode of operation to provide DC power to the DC bus via the DC-DC converter and in a second mode of operation to provide DC power to the DC bus via the rectifier.