According to one aspect, embodiments herein provide a UPS system comprising: a plurality of UPS's configured to be coupled in parallel, each UPS comprising: a bypass line selectively coupled between an input and an output via a bypass switch, wherein the bypass switch is configured to close in a first mode and to open in a second mode, and a controller coupled to the plurality of UPS's and configured to, in response to a determination that input power is at a desired level, control the bypass switch of a first UPS in the plurality of UPS's to operate in the first mode and provide a continuous output current waveform with an RMS value to the load, and selectively control the bypass switch of each other UPS to operate in the first mode such that an output current waveform provided by each UPS includes at least one delay period.