Analysis on the meaning of UPS power input factor
As an important part of the power supply system, UPS power supply is also the load of the power grid, so its input power factor is an important electrical performance indicator to measure whether it pollutes the power grid. If the input power factor is low, it means that it absorbs useful power from the grid at the same time it also absorbs reactive power, and the result is to increase the configuration capacity of the system, affect the power supply quality of the system, reduce the efficiency of the UPS power supply, and increase the operating cost of the UPS power supply.
The input power factor of the backup and online interactive UPS is equal to the power factor of the UPS output load. When the mains is normal, their voltage regulation link does not have the power factor regulation function, but it will not increase the power factor distortion of the grid. The input AC/DC converter of the traditional dual conversion UPS is a controllable rectifier filter circuit, due to the influence of high harmonics, its input power factor is extremely low, only about 0.8, and has nothing to do with the nature of the UPS output load. At the input end, the traditional dual conversion UPS using high-frequency rectification, as well as the UPS composed of high-frequency conversion series parallel compensation circuit, the input power factor is very high, in a large input voltage and load range can reach 0.99, and has nothing to do with the nature of the UPS power output load.
The power department has requirements for the input power factor of electrical equipment, especially for high-power electrical equipment, whose input power factor is required to be above 0.95, when the relevant requirements are not met, it is necessary to configure passive or active power factor compensation links and equipment. If the AC/DC converter of the UPS is changed from 6 pulse rectifier to 12 pulse rectifier, and the corresponding inductance capacitor filter is configured, the input power factor of this type of UPS can be increased to more than 0.95, but the cost of the whole machine will increase by nearly 20%, and when the input voltage waveform distortion is too large, it may cause oscillation of the input filter. The UPS system and load security are affected.