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{{Short description|Component responsible for regulating electrical power}}
{{confused|Power Processing Unit}}
{{More citations needed|date=April 2020}}
A '''power processing unit''' ('''PPU''') is a circuit device that convert an electricity input from a [[utility power|utility line]] into the appropriate [[voltage]] and [[electric current|current]] to be used for the device in question. They serve the same purpose as [[linear amplifier]]s, but they are much more efficient, since the use of linear amplifiers results in much power loss due to the use of a [[resistor]] to change the voltage and current. Instead of using a resistor, PPUs use [[switch]]es to turn a signal on and off quite rapidly in order to change the average current and voltage. In this way, they could be conflated with [[DC-AC converter]]s, but the frequency at which they switch the signal on and off is a few orders of magnitude higher than that of AC signals. They are used to convert the current and voltage of both [[direct current]] (DC) and [[alternating current]] (AC) signals.<ref>Ned Mohan. ''Electric Machines and Drives: A First Course.'' Minneapolis: John Wiley and Sons, 2012</ref>

==Spacecraft==
In the context of [[spacecraft]], the power processing unit (PPU) is a module containing the [[electrical]] subsystem responsible for providing [[electrical power]] to other parts of the spacecraft. The PPU needs to be able to cope with varying [[dynamic demand (electric power)|demands]] for power output and provide that power in the most efficient manner possible.

There are two main constraints placed on PPUs:

* [[Electricity generation|Power generation]] from, for instance, a [[photovoltaic array|solar array]] or [[radioisotope thermoelectric generator]] where power generation can vary based on external conditions.
* [[Isoelastic utility|Power utilization]], which varies depending on the current internal activities performed by the spacecraft such as burst [[radio transmission]] or external demand factors like outside temperature and the need to provide heat to maintain constant internal temperature.

Major considerations in building PPUs are [[weight]], [[measurement|size]] and [[efficiency]].<ref name="The Future is NEXT in Ion Propulsion">{{cite web|url=http://www.inspacepropulsion.com/FactSheets/EP%20Fact%20Sheet.pdf|title=The Future is NEXT in Ion Propulsion|access-date=2008-10-13|archive-url=https://web.archive.org/web/20081120170028/http://www.inspacepropulsion.com/FactSheets/EP%20Fact%20Sheet.pdf|archive-date=2008-11-20|url-status=dead}}</ref>
<ref name="NASA report">{{cite journal|url=https://arc.aiaa.org/doi/10.2514/6.2004-3453|title=An Overview of the High Power Electric Propulsion (HiPEP) Project|date=July 2004|first1=Fred |last1=Elliott|first2=J. |last2=Foster |first3=M. |last3=Patterson|journal=40th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit|doi=10.2514/6.2004-3453 |isbn=978-1-62410-037-6 |access-date=January 15, 2023|url-access=subscription}}</ref>

Most PPUs process and supply [[direct current]] because that is what is generated by a solar array.

The PPU is also responsible for [[voltage]] conversion and supplying the required voltage to other subsystems of the spacecraft.

== References ==
{{reflist}}

[[Category:Spacecraft components]]
[[Category:Electrical engineering]]

Power processing unit - Revision history

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