Working principle and advantages and disadvantages of backup UPS power supply. At present, UPS uninterruptible power supplies on the market are mainly divided into two categories: online UPS power supplies and backup UPS power supplies. When loading low-power devices, if the device itself does not have high requirements for electrical energy, a backup UPS power supply is generally used for loading. If the load is very precise or the data is important, it is recommended to purchase an online UPS power supply.
Working principle of backup UPS power supply
When the mains power is normal, it is supplied to the electrical equipment through a simple voltage regulation filter, and the battery is in a charging state. When there is a power outage, the inverter works to convert the DC power provided by the battery into stable AC power output to the electrical equipment. Due to the fact that the inverter does not work when the mains power is normal, and only starts working when the battery is discharged during a power outage, this type of UPS is called a backup UPS.
Backup UPS power supply is mainly suitable for situations where the power supply quality requirements are not high due to the low fluctuation of the mains wave. The switching time of backup UPS is generally less than 10 milliseconds, so it is not suitable for use in critical locations where power supply cannot be interrupted. However, in reality, the switching time is very short, and the switching power supply of a typical computer or electrical device should be able to last for about 10 milliseconds when the power is cut off. Electrical devices generally do not have problems due to this switching time.
Advantages and disadvantages of backup UPS power supply
Advantages: Small size, high efficiency, low price, and low operating costs. Due to the fact that the inverter is in a non working state under normal circumstances, the power grid directly supplies energy to the load, so the energy conversion efficiency of the backup UPS is very high. The service life of a battery is generally 3-5 years.
Disadvantages: The load is not truly isolated from the online power supply system; Long conversion time and lack of true static switches mean that the time required to convert the load to the inverter is relatively long. Although this conversion time is acceptable in some application scenarios, this performance cannot meet the requirements of large or complex sensitive loads; The output voltage cannot be adjusted; The output frequency depends on the frequency of the AC input power supply and cannot be adjusted.
When there is a power failure in the power grid, there is a long transition time from grid power supply to inverter power supply. For devices that require high power quality, the length of this conversion time is crucial. Furthermore, due to the infrequent operation of the inverter in the backup UPS power supply, it is difficult to grasp the dynamic status of the inverter, which can easily lead to hidden faults. Backup UPS power supplies are generally used on some non critical low-power devices.