Uninterruptible Power Supplies

Uninterruptible Power Supplies (UPS) are used to maintain high-quality and uninterrupted delivery of electricity to network and server equipment, process units and other important electrical consumers.

The UPS ensures continuous processing and storage of information, data transfer, continuity of technological and business processes, as well as correct completion of computing or production processes in case of significant interruptions in primary power supply.

UPS construction

The source circuit designer is based on converting the input mains voltage to DC voltage (performed by a rectifier), connecting a battery to the resulting DC bus, and converting the DC voltage back to AC voltage using an inverter. When the primary power supply fails, the energy stored in the batteries is used to power the load.

Topology of sources

Off-Line and Line-Interactive UPS building technologies are used for small load capacities, where the load is supplied in normal mode directly from the primary network, and the inverter (and, accordingly, energy from the battery) is connected to the load through switching equipment in case of failure of the primary power supply. The connection time does not affect the operation of most modern computer loads that have large capacitors in their power supplies.

In the third UPS topology called On-Line, the rectifier permanently supplies the inverter with input power and charges the bypass accumulator, while the inverter is permanently connected to the load, so no time for switching to battery power (equal to 0) is provided. Because of the double energy conversion, this technology for building sources also has another name Double Conversion.

The Off-Line topology has the simplest design and is used in low-cost UPS series for individual protection of desktop computers and other compatible low-power equipment.

Line-Interactive sources also provide inverter switching, but have a number of options, namely, the output waveform has been improved when operating from the inverter, a simple stabilizer is installed at the input of the apparatus to adjust the load voltage level and reduce the number of events leading to switching to the battery. Such UPSs are used for loads up to 3–5 kVA, allowing a short-term power supply interruption for the time of switching, in systems without increased requirements for ensuring the reliability of the uninterruptible power system and the redundancy of its elements.

All uninterruptible power systems with a capacity of more than 5 kVA are overwhelmingly built on the basis of On-Line topology equipment.

Single-phase and three-phase solutions

The sources also differ in phase between input voltage and output voltage:

• Single-phase input – single-phase output.
• Three-phase input – single-phase output.
• Three-phase input – three-phase output.

Form Factor

Depending on the installation requirements, UPS equipment come in three versions, namely, table apparatus, floor tower-type, as well as built into standard telecommunications cabinets Rack-type. The most popular rack- and tower-type models are available in versions that allow for both installation methods with simple installation steps and removable accessories.

Powerful UPS

Modern server rooms and data centers are characterized by the use of UPS of medium and high power topology On-Line, Double Conversion. Traditionally, a medium or high power monoblock UPS with a service bypass panel (bypass switch), input and output power supply boards is used.

Increasing reliability, redundancy

In order to increase the reliability of the power supply to critical consumers, monoblock UPSs are operated with redundant sources in parallel to maintain full load power in case of malfunctions in one of the UPS of the system. The development of parallel redundant systems in a single housing has led to the creation and distribution of modular uninterruptible power supplies.

Modular sources

Modular sources are the most technological and efficient solution for most of data center vital loads. The modular back-up architecture easily scales in power and battery life as needs grow or reliability requirements increase.

Hot-swappable power, battery and control modules reduce mean time to repair and simplify maintenance. The modular design allows you to create a redundant power system, installed in a single housing and designed to power critical applications in server rooms and switching nodes.

Software and Communications Capacity

All UPSs are equipped with standard computer interfaces, network cards to provide communication via interfaces such as SNMP, other network protocols and industrial interface buses.

The delivery includes software for correct shut down of the operating system of computing equipment upon a signal from the UPS. All UPS manufacturers also offer software for monitoring and controlling the power supply source itself from a single computer, via small and wide area data transmission networks.