UPS (Uninterruptible Power Supply), also known as Uninterruptible Power System, combines batteries (often maintenance-free lead-acid batteries) with a main unit to convert DC power to AC power through inverters and other circuit modules. Its primary purpose is to provide stable and uninterrupted power supply to individual computers, computer network systems, or other electronic devices such as solenoid valves, pressure transmitters, etc.
In this article, we will delve into the internal structure of UPS power supplies, offering an introductory understanding of how UPS power supplies operate. A correct understanding of the principles behind UPS power supplies can assist in reducing operational errors and prolonging the lifespan of UPS power supply units during routine maintenance.
From a basic application principle standpoint, a UPS power supply is an energy storage device that utilizes an inverter as its main component to deliver stable voltage and frequency output. It mainly consists of rectifiers, batteries, inverters, and static switches.
Internal Structure of UPS Power Supply:
- Rectifiers: Rectifiers convert AC power to DC power. They serve two main functions: converting AC to DC for load supply after filtering, and providing charging voltage to the battery.
- Inverters: Inverters convert DC power to AC power and consist of an inverter bridge, control logic, and filtering circuit.
- Batteries: UPS systems use batteries for energy storage. Comprised of multiple batteries connected in series, their capacity determines the duration they can provide power. Batteries store energy when the mains power is available and supply it to the inverter or load during power outages.
- Static Switches: Static switches, also known as solid-state switches, are non-contact switches controlled by logic controllers. They can be either transfer or parallel types, used for automatic switching between power sources or paralleling inverters with the mains power or multiple inverters.
UPS power supplies consist of an AC + DC charging + DC-AC inverter system. The batteries in a UPS are charged when the mains power is available. In case of a power outage, the batteries immediately supply stored DC power to the inverter to convert it to AC power for the connected devices, ensuring continuous power supply. Typically, the backup time provided by batteries in small to medium power UPS systems ranges from 10 to 30 minutes.
