Space P
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Tu Dresden
Set of flashcards Details
| Flashcards | 115 |
|---|---|
| Language | Deutsch |
| Category | Technology |
| Level | University |
| Created / Updated | 13.02.2021 / 04.03.2021 |
| Weblink |
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Isolator
"Energielücke (energy gap)" zum nächsten erlaubten Leitungsband so groß, dass Valenzelektron keine Energie aus einem angeregten Feld aufnehmen kann, um sie zu überwinden. Z.B. Diamant: Eg = 5,3 eV Þ Bei Raumtemperatur kein Strom.
Leiter / Metalle:
Halbleiter
EIgenleiter
Störstellenhalbleiter
"Einbau" von Fremdatomen in Halbleiterkristall
5-wertige Fremdatome in 4-wertigen Halbleiter (z.B. As, Sb in Si, Ge) Þ geben leicht "überzähliges" Elektron an das Leitungsband des Halbleiters ab (Donatoren Þ n-Typ).
führt zu frei beweglichen Elektronen im Leitungsband und zu positiven unbeweglichen Donatorionen Þ Überschusshalbleitung
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3-wertige Fremdatome in 4-wertigen Halbleiter (z.B. B, Ga in Si, Ge) Þ nehmen leicht ein Elektron aus dem Valenzband auf (Akzeptoren Þ p-Typ) Þ bewegliche Löcher im Valenzband (und unbewegliche, einfach negativ geladene Akzeptorionen) Þ Mangelhalbleitung
p-n-Übergang – die Diode
photovoltaischer Materialien
Wirkungsgrade Solarzelle
Elektrochemische Wandlung Vorteile
Konventionelle galvanische Elemente
Reagierende Stoffe sind chemisch an die Elektrode gebunden
d.h. die Elektrode wird verbraucht Ø Batterien
Unkonventionelle galvanische Elemente
Reagierender Stoff wird zur Elektrode geführt, d.h. kein Abbau der Elektrode
Brennstoffzellen
Energiesysteme für Raumfahrzeuge
Batterie zusammenfassung
Fuel Cell allgemein
Anforderungen an ein regeneratives Brennstoffzellensystem
spacecraft submodules
power range of modern space station and their the amount used for the payload
110 kW ISS
50 kW Payload
general PL~0.45 + Power_total
general power on satellites
ca 4-5 W array power for 1 kg
General Power System Functions
Power system configuration overview
6 Energy conversion / Power generation units
Primary Batteries
Solar
RTG
Fuel Cells
Nuclear
Solar Dynamic
5 Energy storage units
Secondary
Batteries
Super Caps
Reversible Fuel Cells
Regenerative Fuel Cells
EnergyWheels
3 storage control
-Battery charge control
-Battery discharge control
- Voltage regulator
Power distribution unit
Power regulation & distribution function
Regulate the bus voltage to the required voltage level
- Regulate the power output (voltage and current) from solar cells and energy storage systems
- Regulate the voltages during charging of energy storage systems
Provide direct current (DC)or alternating current (AC)
pro cons DC / AC
DC
Low power demands
Low transmission distances
AC
High power demands
High transmission distances
Batteries, fuel cells, solar cellsproduce direct current(DC)
Power conditioning & control - 2 types
PPT - explanation
When a load is directly connected to the solar panel, the operating point of the panel will rarely be at peak power. The impedance seen by the panel determines the operating point of the solar panel. Thus by varying the impedance seen by the panel, the operating point can be moved towards peak power point. Since panels are DC devices, DC-DC converters must be utilized to transform the impedance of one circuit (source) to the other circuit (load). Changing the duty ratio of the DC-DC converter results in an impedance change as seen by the panel. At a particular impedance (i.e. duty ratio) the operating point will be at the peak power transfer point. The I-V curve of the panel can vary considerably with variation in atmospheric conditions such as irradiance and temperature. Therefore, it is not feasible to fix the duty ratio with such dynamically changing operating conditions.
Full energy source overview
ISS m2 of solar and power
3000 m² - 250 kW
photo efficiency lab vs final
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