-
1 primary switch mode power supply
- импульсный источник электропитания с коммутацией тока на первичной стороне
импульсный источник электропитания с коммутацией тока на первичной стороне
-
In primary switch mode power supplies, the AC mains voltage is first rectified and smoothed and then chopped ("switched"). Chopping means that the DC voltage is switched periodically at a frequency of 40 to 200 kHz using a power transistor.
In contrast to linearly regulated power supplies, the power transistor does not act as a variable resistor but as a switch instead. This generates a square-wave AC voltage that is transformed to the secondary circuit using a high-frequency transformer. In the secondary circuit, the voltage is rectifi ed and smoothed. The quantity of energy transformed to the secondary circuit is controlled, depending on the load, by varying the chopping rate. The longer the transistor is conductive, the higher is the quantity of energy transformed to the secondary circuit ( pulse width modulation).
Due to the use of high-frequency AC voltage, primary switch mode power supplies have the decisive advantage that their transformer can be of much smaller size than required for the transformation of low frequencies. This reduces the weight and the dissipation inside the unit. The effi ciency of these units is between 85 and 95 %. Since the output voltage does not directly depend on the input voltage, these units can be used for a wide input voltage range and can even be supplied with DC voltage. Furthermore, it is possible to buffer short-time mains voltage breakdowns up to 200 ms. However, the power failure buffering time is limited by the size of capacitor C1 since a longer buffering time requires a higher capacity and thus a bigger size of the capacitor. Especially in case of small power supplies this is not desirable.
Therefore, a practicable compromise has to be made between the size of the power supply and the buffering time.
Primary switch mode power supplies can be used for all purposes. For example, they are suitable for the supply of all kind of electronics as well as for electromechanical applications.
[ABB]Тематики
EN
Англо-русский словарь нормативно-технической терминологии > primary switch mode power supply
См. также в других словарях:
wide|band — «WYD BAND», adjective. Electronics. covering, transmitting, or receiving over a wide range of frequencies: »a wideband antenna, wideband magnetic tape … Useful english dictionary
Crystal oscillator frequencies — Crystal oscillators can be manufactured for oscillation over a wide range of frequencies, from a few kilohertz up to several hundred megahertz. Many applications call for a crystal oscillator frequency conveniently related to some other desired… … Wikipedia
Dynamic range — For other uses, see Dynamic range (disambiguation). Dynamic range, abbreviated DR or DNR,[1] is the ratio between the largest and smallest possible values of a changeable quantity, such as in sound and light. It is measured as a ratio, or as a… … Wikipedia
Dynamic range compression — This article is about a process that intentionally reduces the dynamic range of audio signals. For similar reductions caused by circuit imperfections, see Gain compression. For processes that reduce the size of digital audio files, see Audio… … Wikipedia
VHF omnidirectional range — This article is about the radio navigation aid. For other uses, see Vor. D VOR (Doppler VOR) ground station, co located with DME … Wikipedia
Cellular frequencies — All cellular phone networks worldwide utilize a portion of the radio frequency spectrum designated as Ultra High Frequency, or UHF , for the transmission and reception of their signals. The UHF band is also shared with Television, Wi Fi and… … Wikipedia
Mid-range speaker — A midrange speaker A loudspeaker driver that produces the frequency range from approximately 300–5000 hertz is known as a mid range. Midrange drivers are usually cone types or, less commonly, dome types, or compression horn drivers. The radiating … Wikipedia
Loudspeaker — For other uses, see Loudspeaker (disambiguation). An inexpensive, low fidelity 3½ inch speaker, typically found in small radios … Wikipedia
spectroscopy — spectroscopist /spek tros keuh pist/, n. /spek tros keuh pee, spek treuh skoh pee/, n. the science that deals with the use of the spectroscope and with spectrum analysis. [1865 70; SPECTRO + SCOPY] * * * Branch of analysis devoted to identifying… … Universalium
electromagnetic radiation — Physics. radiation consisting of electromagnetic waves, including radio waves, infrared, visible light, ultraviolet, x rays, and gamma rays. [1950 55] * * * Energy propagated through free space or through a material medium in the form of… … Universalium
Antenna (radio) — Whip antenna on car … Wikipedia
