Several classifications of UPS power supply: backup UPS, online UPS, online interactive UPS
UPS power supply can be divided into many types according to different classification methods. Many users do not know this aspect very well. Today UPS power supply engineers will talk about it from the perspective of working methods. The difference between backup UPS, online interactive UPS, and online UPS.
UPS power supplies are divided into backup UPS, online UPS, and online interactive UPS according to their working methods, with their own different performance and characteristics. The different classification standards of the three are mainly based on whether the inverter, the key component of the UPS power supply, is in an online working state, that is, whether the inverter is continuously working when the UPS is on.
1. Backup UPS (referred to as OFF-LINEUPS in English)
As the most traditional The original form of the static UPS power supply has a simple circuit design, and the related technology has been quite mature and widely used. Backup UPS is generally limited to a small power range, and the price is relatively cheap. When the mains power is normal, the inverter will not work, and the mains will directly supply power to the load; when there is a problem with the mains, the inverter will start to work, convert the DC power discharged by the battery into AC power, and maintain the AC output for the load. . Backup UPS can solve the three power problems of power interruption, power surge, and voltage sag. It does not improve other power problems. This traditional backup UPS mainly has the following characteristics:
p>1. The utility rate of utility power is high, up to 98%, but it is limited to linear load.
2. The input power factor and input current harmonics depend on the nature of the load. For non-linear loads, the input non-sinusoidal peak current is very large, and there are disadvantages such as low input power factor, no power loss, and high input current harmonics polluting the grid.
3. The output voltage stability and frequency stability are poor.
4. The mains power is interrupted and the switch is switched to battery power. The conversion time is generally 4ms～10ms.
5. The output transfer switch is limited by the switching current capacity and the action time, so the general backup UPS is mostly below 2KVA.
Second, online UPS (called ON-LINEUPS in English)
On-line UPS is based on series power transmission One of the most widely used types in the UPS market. The circuit is complex, the cost is relatively high, and it has high-quality power output. When the mains power is normal, the mains power enters the rectifier and is rectified into a smooth and stable direct current. Part of it enters the inverter, and after the inverter’s energy conversion, it becomes a pure, pollution-free alternating current for the load; the other part passes through The charger charges the battery. When the mains fails, the UPS automatically starts the battery to supply power, and the internal power of the battery is converted by the inverter to make it a pure, non-polluting AC power to maintain the load. Online UPS can effectively solve the nine power problems of power interruption, power surge, voltage sag, continuous overvoltage, continuous undervoltage, frequency deviation, power supply*, switching transient, and harmonic distortion. Its performance characteristics are as follows:
1. Regardless of whether there is commercial power, the full power of the load is provided by the inverter to ensure high-quality power output.
2. The output voltage stability and frequency stability are high.
3. The mains power is interrupted, the output voltage is not affected in any way, and there is no conversion time.
4. Since all the load power is borne by the inverter, the output of the UPS puts forward restrictions on the load, but the UPS equipped with an output isolation transformer is completely free from application restrictions, such as Santak UPS series products.
5. Since the rectifier also bears 100% of the load power at the same time, the general old-fashioned online UPS has the disadvantages of low input power factor, no power loss, and large input current harmonics that pollute the grid. However, Shante UPS adopts PFC power factor correction circuit The online UPS can increase the utility utilization rate to more than 96%, and minimize the non-power loss caused by the nonlinear load. Therefore, the UPS power supply using the PFC power factor correction circuit is more energy-efficient. This is a backup and online interaction. UPS can't be compared.
3. Online interactive UPS (LINE-INTERACTIVEUPS in English)
Online interactive UPS is a backup UPS The upgraded version has simple circuit and moderate cost, but its performance is higher than the backup UPS power supply. Online interactive UPS can solve the five power problems of power interruption, power surge, voltage sag, continuous overvoltage, and continuous undervoltage. It has no improvement on other power problems. Its performance characteristics are as follows:
p>1. The utility rate of utility power is high, up to 98%, but it is limited to linear load.
2. The input power factor and input current harmonics depend on the nature of the load. For non-linear loads, the input non-sinusoidal peak current is very large, and there are disadvantages such as low input power factor, no power loss, and high input current harmonics polluting the power grid.
3. The output voltage stability and frequency stability are poor, but they are better than the backup type.
4. The inverter is in a hot backup state, which has a suppressive effect on output voltage spikes*.
5. The mains power is interrupted, and the switch to battery power supply, the conversion time is generally ≤ 4ms.
