2. Online interactive
This UPS consists of a battery, a bidirectional inverter (or rectifier/inverter), an automatic voltage regulator, and a transfer switch. Online interactive UPS is a UPS device that lies between backup and online working modes. It combines the advantages of high efficiency of backup UPS and high power supply quality of online UPS. The inverter of the online interactive UPS is always in working state and has bidirectional function. That is, when the input mains power is normal, the inverter of the UPS is in reverse working state to charge the battery and act as a charger. When the mains power is abnormal, the inverter immediately starts the inversion work, converting the DC voltage of the battery pack into AC sine wave output. Online interactive UPS also has conversion time, but it is shorter than backup UPS and has stronger protection function. The line interactive UPS adopts a ferromagnetic harmonic transformer, which has good voltage regulation function when supplied with mains power. However, due to the shared module of the charging inverter, it is difficult to filter out the high-frequency components generated by the inverter when charging the battery, and the charging effect is not very satisfactory. Therefore, it is not suitable for use as a long delay UPS. The price of online interactive UPS is much lower than that of online UPS, only slightly higher than that of backup UPS, making it a suitable UPS for small office or home use.
3. Online style
The online UPS power supply consists of a battery, rectifier, two inverters, and a static switch. It belongs to the series power transmission mode with high output power. Currently, high-power UPS mostly belongs to this form. When the mains power is normal, the online UPS inputs AC voltage and continuously charges the battery through the charging circuit. At the same time, the ACIDC circuit converts the AC voltage into DC voltage, and then uses pulse width modulation technology (PWM) by the inverter to invert the DC voltage into AC sine wave voltage and supply it to the load, playing a role in stepless voltage regulation; When the mains power is interrupted, the backup battery starts to work. At this time, the voltage of the battery is converted into AC sine wave or square wave by the inverter to supply the load. Therefore, whether the mains power supply is normal or during the mains power interruption, the inverter is always in working condition. This fundamentally eliminates the impact of voltage fluctuations and interference from the power grid on the load, truly achieving non-interference, voltage stabilization, frequency stabilization, and zero conversion time for the load. The characteristic of online UPS makes it more suitable for retrofitting long delay uninterruptible power supply systems with external batteries or high-quality generators. Online UPS outputs are mostly sine waves with stable voltage and frequency, so they are often used in places with high power supply quality requirements, such as our central computer room or data center.