Input voltage in MEAN WELL case-type AC/DC converters

Alternating Current (AC) to Direct Current (DC) converters, i.e. AC/DC type converters, are the most common power supplies for various applications. This fact is a consequence of the fact that in order to minimize losses in the transmission of electrical energy, the transmission method on alternating current is more preferable, and the vast majority of consumers of electrical energy operate on direct current.

Currently, the most popular are switching power supplies, in which the conversion of the type of electric current from one to another and the formation of its level occurs with the help of power semiconductor devices operating in the key mode, and passive elements for storing electrical energy (inductances and capacitors) using various topologies. In English, such power supplies are called SMPS - switched-mode power supply, that is, a power supply operating in key mode, which more accurately reflects the principle of its operation.

All pulse AC/DC converters contain a rectifier and input voltage filtering unit, since the operation of power semiconductor devices in the key mode is provided in DC circuits, which is used in one way or another in almost all AC/DC conversion topologies. On the example of an AC / DC converter RS-50, the rectifier and filtering block comes immediately after the input filter:

Block diagram of AC/DC converter RS-50

In practice, the AC voltage is normalized at the level of the effective voltage value, that is, the value by which the power supply network is marked (for example, “220V AC network”). The rms value of the AC voltage is √2 (1.4142) lower than the peak value, so for 220V AC rms value, the peak value will be 311V AC. After the rectification and filtering stage, the DC voltage will be numerically equal to the amplitude value of the AC voltage, that is, the same 311V.

Input AC voltage and rectified voltage

Based on the peculiarity of the inclusion of a rectifier in the composition of AC / DC converters of the pulse type, these converters can also be used as DC / DC converters in high-voltage DC circuits. In fact, the input DC current will pass without any (almost) change through the power supply rectifier. Since MEAN WELL AC/DC converters operate in a wide range of AC input voltage, for example, from 85 to 264V AC for HRP series and HRPG series (except for HRPG-1000 - it has a lower limit of 90V AC), then, accordingly, the input range voltage at direct current will be the same wide - from 120V DC to 370V DC, that is, higher than the normalized effective value also by √2 over the entire range. This rule applies to all series of MEAN WELL packaged power supplies with one exception - series where the input range is selected by the switch 115V / 230V can only be used in DC circuits corresponding to the upper AC voltage range. So for power supplies of the SE-450 , SE-600 , SE-1000 series, the upper range is 180-264V AC, then a DC voltage of 254-370V DC and not lower can be applied to the input.

High-voltage DC circuits are becoming more common in electric vehicles, since in order to reduce losses, it is advantageous to use high-voltage prefabricated batteries and their charge circuits. And to power the end devices, DC / DC converters are used from the high-voltage circuit to the low-voltage on-board circuit (12, 24 or 48V). However, the use of MEAN WELL AC/DC converters as DC/DC converters for such an area can complement the existing SD and RSD series DC/DC converter solutions that are used only in DC circuits.

More detailed technical characteristics are presented in Specifications for case series power supplies , and for questions related to the selection and use of MEAN WELL products, please contact Meanwell@chipdip.ru .