Things you should know about double conversion UPS

There are three basic types of UPS for modern usage. The first one, known as “Off-line” or “Stand-by” UPS, transfers the incoming mains power to the output receptacles. It continuously monitors the line for significant voltage or complete power failure. As either is detected, the UPS switches on the inverter and supplies the battery or batteries’ output power before the sag returns to the secure operating voltage or the primary voltage is restored. The second type is the “Line Interactive” UPS. These units are equipped with an AVR (Automatic Voltage Regulators) that boosts and strengthens power during sag and swell (over voltage) situations. The third type is known as the “On-line” design as its inverter is always “online.” In this system, all incoming power is converted to direct current, filling the batteries and powering the inverter. Double conversion UPS systems provide critical loads with uninterrupted power. Through filtering and converting incoming utility power to DC power, they do this. They then convert the DC power from the inverter to a complete AC output. The inverter is often powered by batteries or flywheels that may have a DC source. A proper online double-conversion UPS protects the crucial load from any transient or voltage irregularities, including surges, sags, swells, and line drops, via this process.

How double-conversion online UPS operates?

The UPS draws power from its battery when the AC input goes out of a specified range so that the UPS output is not affected. This conversion within the UPS between AC input and battery requires many milliseconds in several double-conversion on-line designs. Again, throughout such transformations, the ‘DC-link’ capacitor provides the inverter with stored energy. So, although there is a short power interruption going through the “DC link,” the UPS’s output voltage is unaffected and constant. An online double conversion system is a program linked between the mains and the critical load, providing a stable and consistent supply of power to this load, regardless of the mains’ condition. It does not include moving parts and is fitted with a battery to provide backup power to the load for a specified time.

What is online double conversion?

The words ‘online double conversion’ in terms of the UPS system means as it says. The UPS forms of 5 primary components-

• A rectifier – first conversion;
• An inverter – second conversion;
• A static bypass switch;
• A manual bypass switch;
• A battery.

Advantages of double-online conversion in critical power applications

In a true online double conversion UPS, the inverter is always on, offering a secure, stable power supply necessary for industries requiring uninterrupted uptime. Operate a data center, a hospital, a communications network, a manufacturing facility, or depend heavily on grid access. A double conversion UPS will provide safe, consistent power to your appliances. With a double conversion system that smoothed out raw power fluctuations from brownouts, line noise, voltage transients, and power outages, you will be less susceptible to downtime issues that could cost millions. Online double conversion UPS systems are the ideal system for mission-critical applications as they reduce the possibility of a loss of electrical load. Their stability and performance and improved power usage efficiency (PUE) enhance their ROI.

The Double Conversion On-Line UPS offers nearly perfect efficiency for electrical output. Even so, constant wear on power components can reduce stability, and the energy used by electrical power inefficiency is a large part of the life-cycle expense of the UPS. Even the input power generated by the large battery charger is always non-linear and can interfere with building power wiring.

System Components

The rectifier usually consists of a thyristor bridge that is operated and converts the AC mains into DC. The rectifier’s function is to charge the batteries while simultaneously providing the inverter’s full load and managing system losses.


The opposite of a rectifier is the UPS inverter. A process known as PWM chopped up the DC power available from the DC link. The DC is effectively turned on and off through IGBTs, forming a harmonic rich sine wave in short bursts of various amplitudes and for different periods. The wave is then filtered, and the output of a pure sine wave is generated.

Static bypass

The static bypass is a very rapid electronic transition in a UPS. Power flow is through the rectifier and inverter to the load while the UPS usually operates. Power is also available for static and manual bypass inputs.


Many UPS systems are currently available with a wide variety of monitoring and shutdown software.

The online double-conversion UPS design concept offers superior protection for your loads. When it comes to UPS, load protection remains the main priority. Right Power Technology, founded in 2000, as a pioneer in developing and manufacturing advanced UPS systems and solutions, Right Power Technology now has the enviable distinction of being a significant player in the industry, education, and commercial fields. Visit our official website to see the best ups suited to your requirements.