High voltage DCpower supply system's principle and key issues

The composition of the high-voltage DC power supply system is the same as that of the traditional − 48 V DC power supply system, except that the output voltage level of the rectifier is higher than − 48 v. The system consists of mains power input, high-frequency switching rectifier, distribution panel and battery pack. HVDC power supply system can replace the current AC UPS power supply system to supply power to the data server.

Basic principle of H.V system

The high-frequency AC power used by the internal switch of the computer room is generally converted into the DC power used by the external server, which has high reliability. For servers or minicomputers with strong functions and used in important occasions, two or more modules are configured to operate in parallel.

Although the input of server equipment is AC power supply, the core part is DC / DC conversion circuit. As long as we input a suitable range of DC voltage to DC / DC conversion circuit, we can also safely meet the work of server equipment. In Figure 5-7, because there is no power frequency transformer at the input end, the input DC will not produce short-circuit impedance, so there is no need to have AC input, and there is no need to use UPS without AC, so all adverse factors caused by UPS AC power supply will naturally disappear. If the DC input is reasonably equipped with storage battery and supplemented by remote monitoring to form a reliable DC power supply system, it can replace the AC UPS power supply system to supply power to the server equipment.

Key issues of high voltage system for EAF

The selection of voltage level has become the key problem of the composition of HVDC power supply system. According to the characteristics of the server, there are two main standards for the selection of voltage level of HVDC power supply system.

1. 240V voltage level

The input voltage range of DC / DC is 100VDC ~ 373vdc. Through the analysis of the input voltage of the server power supply and the test data of the server in practice, the view that 240V is a nominal voltage has been recognized.

In the DC voltage supply mode with a nominal voltage of 240V, the battery pack is equipped with 120 2V batteries (40 6V batteries or 20 12V batteries can also be used). At ordinary times, the battery is in floating charge state, and the power supply voltage is 270V. When powered by battery, the minimum voltage is 216v. In the current test, the server can work normally under this voltage.

2. 380V voltage level

The voltage range of this kind of server power supply at the input end of DC / DC is 380vdc ~ 400VDC. For this kind of server power supply, it is necessary to select a high-voltage DC power supply system of 380V or above.

However, this power supply mode is not applicable to the existing domestic server equipment and is a forward-looking preparation for the future computer room construction and server design. Therefore, to adopt this power supply mode, the cooperation of server manufacturers is required, that is, the server power supply should support the 380V high-voltage DC power supply mode.

Compared with 240V voltage level power supply mode, 380V voltage mode will reduce cable copper consumption and line loss.