Since the advent of static UPS in the 1970s, from the initial SCR discrete UPS development to today’s use of fully-controlled power devices, the intelligent UPS has gone through a total of 40 years. During these 40 years, UPS has been It is developing in the direction of reducing volume and quality and improving performance indicators.
There are four reasons why UPS has developed so fast:
①The rapid development of modern communications, electronic computers and their networks, as well as the rapid expansion of their application fields, have placed higher and higher requirements on power quality and reliability, especially the increasingly urgent requirements for uninterrupted power supply, which has promoted the development of UPS ;
②The rapid development of new high-power switching devices has created conditions for the development of UPS;
③The rapid development of power electronics technology (electronic technology, device development, manufacturing and production technology and control technology) has laid a theoretical foundation for the development of UPS;
④ The research and update of the conversion methods and methods of electric energy by professional scientific and technical personnel directly increased the development speed of UPS.
From the perspective of technological development, power conversion methods and UPS structure, the development of UPS can be divided into the following four stages.
① From 1970 to 1980, it was the early development stage of UPS. In this stage, the UPS used the semi-controlled switching device SCR as the switch, and used the multiple superposition method to improve the output voltage waveform, and adjusted the voltage by adjusting the angle between the two voltage phasors. , Fully discrete UPS with discrete components and discrete structure, that is, the rectifier, inverter and bypass parts are made into independent equipment, and a complete UPS system can be formed after assembly and connection on the spot. This kind of UPS is called the first generation UPS, which is characterized by poor performance, low efficiency, poor reliability, large volume and quality, large noise, and large external interference.
②From 1980 to 1990, the IGBT full-control device at this time has appeared, but due to its low power, immature application technology, and expensive price, it has not reached the level of popularization. Therefore, GTR is used as the switch, and the SPWM inverter is used with The series-adjustable three-port UPS composed of three-port transformers became the most popular UPS at that time. This kind of UPS is called the second-generation UPS, which is characterized by high overall efficiency, high reliability, and strong anti-electromagnetic interference capability. The disadvantage is that it is large in size and mass, and is noisy.
③From 1990 to 2003, with the update and development of UPS technology, the application technology of the new high-power full-control device ICBT has matured and reached the level of large-scale industrial applications. During this period, the new AC-DC-AC double-conversion structure online UPS using ICBT as the SPWM inverter switch has been widely used. This double-conversion structure UPS has a great advantage, that is, it can be used at the time. Advanced SCR multi-phase phase-controlled rectifiers and IGBT SPWM three-phase half-bridge inverters are connected in series to form an AC-DC, DC-AC full power conversion online UPS, which can be completely unaffected by the pollution of the mains power supply, which greatly improves the UPS The quality of output power became the most commonly used UPS at that time. This kind of UPS is called the third-generation UPS, which is characterized by high output power quality, high reliability, strong adaptability to the mains power grid, and high total conversion efficiency. It was the most popular advanced UPS at the time. .
④From 2003 to 2010, during this period, people conducted in-depth research on the third-generation UPS, and found that there is still potential to be tapped in terms of volume, quality, and conversion efficiency. Therefore, the fourth-generation UPS (low power applications It appeared in 1991). The so-called fourth-generation UPS is essentially a UPS that uses ICBT SPWM high-frequency switching Boost PFC rectifier with power factor correction function to replace the SCR multi-phase phase-controlled rectifier boosted by the input rectifier transformer. This kind of UPS is called high frequency UPS, and the replaced UPS is called industrial frequency UPS.