When users buy high power UPS, they often face the confusion of choosing between the frequency machine and the high frequency machine. As far as UPS manufacturers are concerned, of course, they all think they are good for themselves. Manufacturers who offer power frequency machines say that the stability and reliability of power frequency machines are high; manufacturers who provide high-frequency machines will say that the high frequency machine saves space and the cost is relatively low. In fact, the power frequency machine and high frequency machine in the end are superior, it is difficult to generalize, it can be said that there are advantages and disadvantages. On the basis of fully understanding the two UPS models, users should objectively examine their own applications and needs and choose the products suitable for their own needs.

The principle analysis of the frequency machine and the high frequency machine

The power frequency machine and the high frequency machine are divided according to the working frequency of the UPS design circuit. The power frequency machine is designed with the traditional analog circuit principle, which is composed of the thyristor (SCR) rectifier, the IGBT inverter, the bypass and the power frequency boost isolation transformer. Because the frequency of its rectifier and transformer is working frequency 50Hz, it is called industrial frequency UPS as the name suggests. The high frequency machine is usually composed of IGBT high frequency rectifier, battery converter, inverter and bypass. IGBT can be controlled by adding in the gate driver to control the turn-on and turn off switching frequency IGBT rectifier, usually to tens of kHz in thousands of Hertz, even up to tens of kilohertz, far higher than the power machine, so called high frequency UPS.

When users buy high power UPS, they often face the confusion of choosing between the frequency machine and the high frequency machine. As far as UPS manufacturers are concerned, of course, they all think they are good for themselves. Manufacturers who offer power frequency machines say that the stability and reliability of power frequency machines are high; manufacturers who provide high-frequency machines will say that the high frequency machine saves space and the cost is relatively low. In fact, the power frequency machine and high frequency machine in the end are superior, it is difficult to generalize, it can be said that there are advantages and disadvantages. On the basis of fully understanding the two UPS models, users should objectively examine their own applications and needs and choose the products suitable for their own needs.

The principle analysis of the frequency machine and the high frequency machine

The power frequency machine and the high frequency machine are divided according to the working frequency of the UPS design circuit. The power frequency machine is designed with the traditional analog circuit principle, which is composed of the thyristor (SCR) rectifier, the IGBT inverter, the bypass and the power frequency boost isolation transformer. Because the frequency of its rectifier and transformer is working frequency 50Hz, it is called industrial frequency UPS as the name suggests. The high frequency machine is usually composed of IGBT high frequency rectifier, battery converter, inverter and bypass. IGBT can be controlled by adding in the gate driver to control the turn-on and turn off switching frequency IGBT rectifier, usually to tens of kHz in thousands of Hertz, even up to tens of kilohertz, far higher than the power machine, so called high frequency UPS.

When users buy high power UPS, they often face the confusion of choosing between the frequency machine and the high frequency machine. As far as UPS manufacturers are concerned, of course, they all think they are good for themselves. Manufacturers who offer power frequency machines say that the stability and reliability of power frequency machines are high; manufacturers who provide high-frequency machines will say that the high frequency machine saves space and the cost is relatively low. In fact, the power frequency machine and high frequency machine in the end are superior, it is difficult to generalize, it can be said that there are advantages and disadvantages. On the basis of fully understanding the two UPS models, users should objectively examine their own applications and needs and choose the products suitable for their own needs.

The principle analysis of the frequency machine and the high frequency machine

The power frequency machine and the high frequency machine are divided according to the working frequency of the UPS design circuit. The power frequency machine is designed with the traditional analog circuit principle, which is composed of the thyristor (SCR) rectifier, the IGBT inverter, the bypass and the power frequency boost isolation transformer. Because the frequency of its rectifier and transformer is working frequency 50Hz, it is called industrial frequency UPS as the name suggests. The high frequency machine is usually composed of IGBT high frequency rectifier, battery converter, inverter and bypass. IGBT can be controlled by adding in the gate driver to control the turn-on and turn off switching frequency IGBT rectifier, usually to tens of kHz in thousands of Hertz, even up to tens of kilohertz, far higher than the power machine, so called high frequency UPS.

When users buy high power UPS, they often face the confusion of choosing between the frequency machine and the high frequency machine. As far as UPS manufacturers are concerned, of course, they all think they are good for themselves. Manufacturers who offer power frequency machines say that the stability and reliability of power frequency machines are high; manufacturers who provide high-frequency machines will say that the high frequency machine saves space and the cost is relatively low. In fact, the power frequency machine and high frequency machine in the end are superior, it is difficult to generalize, it can be said that there are advantages and disadvantages. On the basis of fully understanding the two UPS models, users should objectively examine their own applications and needs and choose the products suitable for their own needs.

The principle analysis of the frequency machine and the high frequency machine

The power frequency machine and the high frequency machine are divided according to the working frequency of the UPS design circuit. The power frequency machine is designed with the traditional analog circuit principle, which is composed of the thyristor (SCR) rectifier, the IGBT inverter, the bypass and the power frequency boost isolation transformer. Because the frequency of its rectifier and transformer is working frequency 50Hz, it is called industrial frequency UPS as the name suggests. The high frequency machine is usually composed of IGBT high frequency rectifier, battery converter, inverter and bypass. IGBT can be controlled by adding in the gate driver to control the turn-on and turn off switching frequency IGBT rectifier, usually to tens of kHz in thousands of Hertz, even up to tens of kilohertz, far higher than the power machine, so called high frequency UPS.

"Pass AC resistance DC", protection load for UPS failure

The AC/DC transformation part of the high UPS part is designed by high frequency, which improves the input power factor of UPS (0.98) and the input voltage range. The high frequency of DC/AC inversion reduces the volume and the power density of the output filter inductor. Due to no output isolation transformer, once the IGBT of the inverter bridge arm is short circuited, the BUS bus DC high voltage will be added to the load, endangering the safety of the load. The output isolation transformer has the ability of "communicating through alternating current resistance", which can solve such problems and can make the load run safely when the UPS fails.

Performance comparison between frequency machine and high frequency machine

In terms of reliability, the power frequency machine is superior to the high frequency machine

The power frequency machine adopts the thyristor (SCR) rectifier. After more than half a century of development and innovation, the technology has been very mature, and its current impact resistance is very strong. Because SCR belongs to the semi control device, there will be no straight through, false trigger and so on. In contrast, the IGBT high-frequency rectifier used by the high-frequency machine has higher switching frequency, but IGBT has strict voltage and current working area and low impact resistance when working. Therefore, in terms of overall reliability, the IGBT rectifier is lower than the SCR rectifier.

In terms of environmental adaptability, the high frequency machine is superior to the power frequency machine

The high frequency machine takes the microprocessor as the processing control center, burns the complicated hardware analog circuit in the microprocessor, and controls the operation of UPS by software program. Therefore, the volume and weight have been significantly reduced, the noise is also small, and the impact on space and environment is small, so it is more suitable for the office with less demanding reliability. Because of this, many manufacturers of small and medium power UPS generally launch the high frequency machine.

The power frequency machine is superior to the high frequency machine in the requirement of the load to the zero ground voltage.

High power three-phase high frequency machine zero line will introduce rectifier and as neutral positive and negative bus, this structure will inevitably result in the rectifier and inverter high frequency harmonic coupling on the zero line, zero voltage caused by the uplift load, zero voltage elevation, it is difficult to meet the space requirements of the zero voltage is less than 1V IBM and HP server manufacturers. In addition, when the power and generator are switched, the high frequency machine often needs to bypass operation due to the lack of zero line, which may cause major failures of load flashover under certain working conditions. Because the rectifier does not need zero line to work, the UPS can maintain normal power supply when the zero line is disconnected.

Concluding remarks

Structurally speaking, the difference between the UPS of the power frequency machine and the UPS of the high frequency machine is mainly on the isolated transformer, while the use of the power frequency machine to the isolation transformer largely improves the reliability of the UPS. In terms of comprehensive performance, the power frequency machine and the high frequency machine each have the advantages and disadvantages, at least at present, there is no question of who to replace who. When users choose equipment, they should be based on their own actual needs, rather than blindly follow them. For example, users to large-scale data center construction, so the reliability and stability requirements should be put in the first place, high power UPS power machine should be preferred; if the application of the general office, or taking into account the main occupation of space equipment, it can be applied to the high frequency machine UPS.

Tian Heng is looking forward to a wide range of cooperation with customers from all walks of life to share our products and success.

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