Power frequency UPS is not equal to industrial UPS(2)

In 1962, GE developed the first 600V / 200A GTO, which overcomes the shortcomings of ordinary thyristors that cannot be turned off by gate control.However, GTO has always been technically inadequate, and it is easy to burn in application.In 1974, Japanese companies such as Toshiba adopted NTD single-chip and made breakthroughs in GTO development through computer simulation technology, producing 1200V / 2000A GTO.The larger and larger bipolar transistors have achieved 500V / 200A / 50 (current amplification factor hfe) using vertical structure, Darlington cascade technology and multi-cell integrated parallel connection. At this time, it has been called GTR.In the late 1970s, due to advances in semiconductor ultra-clean technology, the problem of "surface state" impurity ions that had long hindered MOS devices was also controlled and resolved.The device originally conceived came later because of technical problems, but its performance is more superior and easier to manufacture.Therefore, MOS integrated circuits developed rapidly in the late 1970s.In the early 1980s, the vertical diffusion MOS power device VDMOS based on MOS integrated circuits also gradually matured with the efforts of International Rectifier.In 1982, American Indians B.J.Baliga and Motorola of GE Company invented IGBT almost simultaneously.In 1984, GE's V.A.K.Temple invented the MCT (H) with more superior performance. It was commercialized in 1991, but in the late 1990s, it was stuck due to the excessively complex structure and low yield.In the early 1990s, the IGBT-based Intelligent Power Module (IPM—Intelligent Power Module) developed by Mitsubishi Corporation of Japan has entered mature applications after nearly ten years of improvement.In 1995, Siemens introduced the non-punch-through structure (Non Punch Through) NPT-IGBT, which was a milestone in technology.Using NPT-IGBT technology and GTO wafer technology, 6500V / 600A NPT-IGBT can be made.Therefore, in the mid-1980s, the UPS inverter entered the high-frequency era, and the IGBT operating frequency is usually 3 to 10KZ at the switching frequency.But because the DC voltage of the bus is not boosted by DC / DC, a power frequency boost transformer is still required, so this type of machine is still called a power frequency machine, and the pure words are removed, as shown in Figure 4 below.

In the same period, a power-specific UPS that best represented the characteristics of industrial machines was born.With the introduction of DCS, the power industry began to use UPS in batches, and found that the battery failure in the UPS was high. Users at home and abroad, such as substations and power plants with DC screens, put forward an idea for UPS battery management ", That is, the UPS is not equipped with batteries and charging, and the DC terminal is directly connected to the DC screen.In this way, the DC maintenance personnel of the user ensures the safety of the battery, improves the reliability of the UPS, and reduces the battery input.as shown in Figure 5 below.

The characteristics of the special power UPS that can best represent the customized characteristics of industrial machines are as follows:
1、The power UPS itself does not have a battery pack, and directly uses the battery pack hanging on the DC screen bus, so the power UPS may not have a charger.
2、The power UPS itself does not have a battery pack, and directly uses the battery pack hanging on the DC screen bus, so the power UPS may not have a charger.
3、provide a cold start function for emergency electricity. .
4、The power-specific UPS is generally supplied by the three-part panel of the power UPS host, bypass voltage stabilizer cabinet, and output feeder cabinet.
5、Since most DCS system loads in power plants are single-phase loads, single-phase load distribution lines are simple and easy to maintain. Therefore, the power-specific UPS mostly outputs single-phase 220V, and the capacity is generally within the range of 160kVA. The above-specified power-specific UPS may also be called industrial-frequency power-specific UPS or industrial-frequency industrial-type UPS.
After 2000, high-current and high-voltage IGBTs have been modularized. In addition to the discrete components introduced above, their integrated drive circuits have now been manufactured. It has better performance, higher reliability and smaller volume. For IGBT series modules, the withstand voltage has reached 1200V / 1700V / 2000V / 2500V / 3300V / 6500V. At this time, the rectifier of the UPS has also become high-frequency. Usually, IGBT series modules with a voltage of 1200V are used, and the switching frequency is 3 to 10KZ.
In the UPS shown in Figure 6, the mains input is modulated and rectified by IGBT to obtain a DC voltage (400-500V), which is modulated by an inverter to output an AC line voltage (about 310V), and finally rises to the desired line through the output transformer Voltage 380V stable voltage. Since the power frequency step-up transformer is still required, even if the rectifier and inverter are both high-frequency, this type of machine is still called a power frequency machine

The generation of the high-frequency machine is called UPS as shown in Figure 7, the mains input is modulated and rectified by IGBT, and the DC voltage is boosted to about 800V, and the required line voltage of 380V is output after the modulation and filtering of the inverter. Because this type of rectifier and inverter are high-frequency, and there is no power frequency step-up transformer, it is called a high-frequency machine.

With the advent of the high-frequency machine era, especially the IGBT rectification technology with high-frequency characteristics, its input power factor ≥0.95, input THDI ≤5%, less pollution to the power grid, and is called green rectification. The industrial machine manufactured by machine technology is called a new generation of green industrial machine. It is designed to retain the dominant characteristics of the industrial machine, high EMC immunity; high IP protection level; output power frequency isolation transformer; and recessive characteristics: the control algorithm and sampling design of the rectifier and inverter. Now it is also gradually applied in the data centers in the industrial field, as far as technology is concerned, the future development direction of industrial machines. The UPS shown in Figure 8 below.

Based on the above, we can summarize as follows: the industrial frequency machine and the high frequency machine are two different technical routes or frameworks,When industrial machines and business machines are used by industry users, the level of reliability and applicability is high. Therefore, both industrial and high frequency machines can be used as industrial machines. Similarly, both commercial and high frequency machines can be commercial machines.

Industrial UPS uses a highly engineering componentized approach.Its definition is user-centered, and together with the user to study and determine the industry's power consumption environment (such as input three-phase unbalance, power surge, harmonics, etc.), load environment (such as rectifier, transformer, motor, etc.), space and Climate environment (such as dust, high temperature, high humidity, altitude, etc.), and "tailor-made" UPS system solutions. This highly engineering componentized approach greatly improves the reliability and applicability of the UPS system.

Regarding the selection of industrial-frequency industrial machines or high-frequency industrial machines, users in various industries have their determined habits and experience, and it is difficult to be improved in a short time.Therefore, when we promote the widespread use of industrial-grade UPS, we must realistically solve the difficult problems of users, and we must introduce high and new technology in a timely manner. In short,power frequency UPS is not equal to industrial UPS.

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