UPS power supply, also known as uninterruptible power supply or backup power supply, is an energy storage device that can provide temporary power supply when the main power supply (mains) is interrupted. And this energy storage device can be classified into different types from different perspectives, with the most common classification being: power frequency UPS power supply and high-frequency UPS power supply.

A、 The difference between power frequency UPS power supply and high-frequency UPS power supply:

There are significant differences between power frequency UPS power supplies and high-frequency UPS power supplies in terms of volume, weight, efficiency, output power quality, overload capacity, and application scenarios;

1. High frequency UPS power supply has small size, light weight, fast charging, and is suitable for fast charging and discharging occasions;

2. Power frequency UPS power supply has good output power quality and strong overload capacity, suitable for high-power power supply occasions such as factories, computer rooms, etc.

B、 There are significant differences between power frequency UPS power supply and high-frequency UPS power supply:1.From a working principle perspective, power frequency UPS uses power frequency transformers. High 

1.frequency UPS power supplies utilize high-frequency switching technology, which results in significant differences in volume and weight between the two. High frequency switching components are used to replace the power frequency transformers in rectifiers and inverters. Make high-frequency UPS power supplies smaller in size, lighter in weight, and easier to carry and install.

2.From an efficiency perspective, high-frequency UPS has higher efficiency because high-frequency switching technology reduces losses. However, due to the use of power frequency transformers, the efficiency of power frequency UPS is relatively low.

3. There are also differences in the output power quality between the two. The output power quality of power frequency UPS is better because power frequency transformers can better suppress harmonic interference. The output power quality of high-frequency UPS is relatively poor, mainly due to harmonic interference from the mains power grid, pulsating currents from UPS rectifiers and high-frequency inverters, and harmonic interference from loads.

4. Power frequency UPS power supply has strong overload capacity. When the equipment is overloaded, due to its strong overload capacity, the possibility of UPS switching to bypass operation is very small. This makes the power frequency UPS more suitable for occasions that require high-power power supply, such as factories, computer rooms, etc.

5. In terms of application scenarios, power frequency UPS power supply is suitable for high-power power supply, such as factories, computer rooms, and other occasions. High frequency UPS, on the other hand, is more suitable for situations that require fast charging and discharging due to its small size, light weight, and fast charging speed.

3、 Advantages and disadvantages of power frequency UPS power supply and high-frequency UPS power supply:

1. Input power factor:

Power frequency UPS power supplies typically use thyristor 6-pulse rectification for input circuits below 200kVA, with an input power factor not exceeding 0.8 and harmonic currents up to 30%. If the generator is connected to the front, the capacity of the generator should be at least 3 times the UPS power; If it is a single-phase low-power UPS, the generator capacity should be at least 5 times the UPS power.

However, the input power factor of any high-frequency machine UPS can reach 0.99 or even higher, with harmonic currents less than 5%. The capacity of the front-end generator is theoretically the same as the UPS power, greatly reducing investment and footprint. Especially the full utilization of municipal power has good economic and social significance.

2. Low power consumption:

Under the same criteria, for example, when the input power factor is required to be above 0.95, the power frequency machine UPS must be equipped with a harmonic filter or changed to 12 pulse rectification. This means that an additional device needs to be added and an output transformer needs to be added, which adds two more links than the high-frequency machine UPS. Due to the influence of these two factors, the efficiency of power frequency UPS is 5% lower than that of high-frequency UPS. At the same capacity of 100kW, the power frequency UPS consumes 50000 kWh more electricity per year than the high-frequency UPS! Today, as the central government calls for energy conservation and emission reduction, energy conservation has profound significance.

3. Small size and light weight:

Due to the presence of output transformers and low-frequency components such as inductors and capacitors that can adapt to 50Hz, the volume and weight of power frequency UPS power supplies are very large. For example, a 200kVA power frequency machine UPS from a certain brand weighs 1380kg, while a 250kVA high-frequency machine UPS from the same manufacturer weighs only 830kg.

4. All digital technology:

The power supply of industrial frequency UPS started with analog technology, and now it generally develops into a combination of digital and analog technology. The reliability of simulation technology is lower than that of digital technology. The high-frequency UPS technology is a fully digital technology, and it goes without saying that its reliability is very high.

5. Strong adaptability to the power grid:

Power frequency UPS power supply is easy to adapt to changes in input voltage of ± 25%; And high-frequency UPS can even adapt to changes in input voltage of ± 30% or more, which greatly extends the battery life of UPS.

6. Able to attenuate the parallel circulation to almost zero:

The parallel connection of power frequency UPS power supply is the direct parallel connection of transformers, and the direct parallel connection of transformers is most likely to generate circulating current, and the path of this circulating current is unobstructed. High frequency UPS power supply has obstacles everywhere on their parallel circulating current path due to the lack of output transformers, and voltage differences less than 2V cannot form circulating current at all. In this case, power frequency machine UPS will form a large circulating current.