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Which is more expensive, power frequency machine or high frequency machine, and which is more popular?

by:Kehua     2022-07-31
Both the power frequency machine and the high frequency machine are UPS with Kehua characteristics of the power frequency transformer, so which one should we choose when we need it? Is it a power frequency machine or a high frequency machine, what is the difference between them? Which is more expensive? This article will go into details. Definition of power frequency machine and high frequency machine Small and efficient. 2. Power frequency machine: UPS using power frequency transformer as rectifier and inverter components is commonly known as power frequency machine. 1. Principle analysis of power frequency machine and high frequency machine 1. Power frequency machine and high frequency machine are distinguished according to the working frequency of the design circuit of UPS. The power frequency machine is designed based on the traditional analog circuit principle, and consists of a thyristor (SCR) rectifier, an IGBT inverter, a bypass and a power frequency step-up isolation transformer. Because the working frequency of the rectifier and transformer are both the power frequency 50Hz, as the name implies, it is called the power frequency UPS. 2. The high frequency machine is usually composed of IGBT high frequency rectifier, battery converter, inverter and bypass. The IGBT can be turned on and off by controlling the drive applied to the gate. The switching frequency of the IGBT rectifier is usually several kilohertz to several tens of kilohertz, even as high as hundreds of kilohertz, which is much higher than the power frequency machine. For high frequency UPS. The output of the high-frequency machine is not isolated by a transformer. If the inverter power device is short-circuited, the high DC voltage on the DC bus (DC BUS) is directly applied to the load, which is a safety hazard, but the power frequency machine does not have this problem. 2. Analysis from the performance comparison between the power frequency machine and the high frequency machine 1. In terms of reliability, the power frequency machine is better than the high frequency machine: the power frequency machine adopts a thyristor (SCR) rectifier. The development and innovation have been very mature, and its resistance to current impact is very strong. Since SCR is a semi-controlled device, there will be no faults such as shoot-through and false triggering. In contrast, although the IGBT high-frequency rectifier used in the high-frequency machine has a high switching frequency, the IGBT has a strict voltage and current working area during operation, and the impact resistance is low. Therefore, in terms of overall reliability, IGBT rectifiers are lower than SCR rectifiers. 2. In terms of environmental adaptability, the high-frequency machine is better than the industrial frequency machine: the high-frequency machine uses the microprocessor as the processing control center, burns the complicated hardware analog circuit into the microprocessor, and uses the software program to program. to control the operation of the UPS. Therefore, the volume, weight and other aspects are significantly reduced, the noise is also small, and the impact on space and environment is small, so it is more suitable for office places with less stringent reliability requirements. Because of this, many manufacturers have generally introduced high-frequency machines for small and medium-power UPS. 3. The power frequency machine is better than the high frequency machine in terms of the load's requirements for the zero-to-ground voltage: the zero line of the high-power three-phase high-frequency machine will introduce a rectifier and serve as the neutral point of the positive and negative busbars, and this structure is unavoidable The ground causes the high frequency harmonics of the rectifier and the inverter to be coupled on the neutral line, which increases the neutral-to-ground voltage, resulting in an increase of the neutral-to-ground voltage at the load end. In addition, when the mains and the generator are switched, the high-frequency generator often has to be switched to the bypass due to the lack of the neutral line, which may cause a major failure of the load flashing under certain working conditions. Because the rectifier does not need the neutral line to participate in the work of the power frequency machine, when the neutral line is disconnected, the UPS can maintain normal power supply. To sum up, the difference between the power frequency machine UPS and the high frequency machine UPS is mainly reflected in the isolation transformer, and the use of the power frequency machine for the isolation transformer greatly improves the reliability of the UPS. In terms of comprehensive performance, power frequency machines and high frequency machines have their own advantages and disadvantages. At least at present, there is no question of who replaces who. When purchasing equipment, users should base themselves on their actual needs, rather than blindly follow them. Which one is more expensive between power frequency machine and high frequency machine The above is the discussion on the topic of which is the more expensive power frequency machine and high frequency machine. Although both are Kehua tools, generally speaking, whichever has better performance is more expensive. If you want to know more information, please follow us more.
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