In an online double conversion uninterruptible power supply (UPS) system, the four main components work together to provide continuous, clean power to the connected load. Here’s a brief overview of each component:
Rectifier: The incoming AC (alternating current) power is converted to DC (direct current) power by the rectifier. Its two main purposes: charging the UPS batteries and providing DC power to the inverter.
UPS Batteries: These are used to store energy. The batteries supply DC power to the inverter, in the event of a power outage or when the incoming power is out of acceptable range. This ensures uninterrupted power to the load. Smaller UPS systems usually house batteries internally within the unit. Larger setups often store batteries in their own standalone cabinets. Users commonly utilise three main types of batteries in uninterruptible power supplies: Lead-Acid, Nickel-Cadmium, and Lithium-Ion.
Inverter: The inverter converts the DC power from the rectifier or batteries back into AC power, supplying it to the connected load. It ensures that the power remains clean and stable by smoothing out spikes, sags, surges, and electrical noise, which helps create a pure sine waveform.
Static Bypass Switch: The static bypass switch provides an alternate path for power to the load. If the UPS system encounters a fault or needs to undergo maintenance, the static bypass switch automatically transfers the load to the bypass line or mains supply. This action ensures a continuous power supply without interruption by bypassing the rectifier, batteries, and inverter.