Download Energy Power System

Energy Power System
Electricity
• Electricity is the flow
of electrons through a
conductor
• Electricity will only
move through a closed
circuit, if the circuit is
broken the flow of
electrons stops
Electricity (cont.)
• Voltage - Electric potential or potential
difference, provided by the battery,
expressed in volts
• Amperage - The strength of an electric
current, flows through the conductors to the
load, expressed in amperes
• Resistance - Is present in any load,
expressed in ohms
Light to Power
• Solar Panels collect
sunlight and convert
them into electrical
power
• For maximum power
solar arrays need to be
perpendicular to the
light rays hitting them.
Orbit Cycle
• During the 30 minute eclipse period the batteries supply
power
• While in insolation period the solar arrays provide power
while the batteries charge for the next eclipse period
Primary and Secondary power
• Primary power is high
voltage power generated
at a centralized source
• Before power is delivered
to users it is stepped down
by a transformer to a set
voltage (secondary power)
• Secondary power is then
delivered to the user
System Overview
• Internal and external
systems
– Internal system distributes
secondary power
– External distributes primary
power
• 8 identical channels of
power (1-4 A/B)
– Each channel supplies 100
amps of current
Internal EPS
• Loads, RPDA, SPDA, DDCU, MBSU, ICC
• Converts primary power to secondary
power
• Routes secondary power to any internal
systems
Loads
• A load is anything that needs electricity to
function.
• Computers, Lights, Pumps, etc.
• Each load requires a certain current (amps)
which is specific to that device
• Not all loads are physically inside the
station, but all are supplied by the same
internal distribution network
SPDA/RPDA/DDCU
• Secondary Power Distribution Assembly
– Supports a single channel of power
• A is even channel B is odd channel
– Routes power to one RPDA and six loads
• Remote Power Distribution Assembly
– Routes power to six loads
• Direct current to Direct current Converter Unit
– This is the unit that converts primary power (~160 V
dc) to secondary power (~124 V dc)
MBSU/ICC
• Main Buss Switching Unit
– Each support 2 channels of power with a total
of 200 amps
– Routes power to two SPDAs
• Interconnecting Cables
– Create a bridge for two or more MBSUs to
share power across them
External EPS
• SARJ, IEA, ECU,
SSU, PCU, BGA,
PVA
• Produces primary
power from the solar
arrays, and stores
power in batteries for
eclipse phase
SARJ
• Solar Alpha Rotary
Joint
• Rotates 4 channels of
power at one time
– Controls rotation
parallel to the main
station truss
IEA
• Integrated Equipment Assembly
• Battery Charge Discharge Unit (BCDU)
– When signaled by the ECU the BCDU begins
charging or discharging the batteries
• Batteries (BAT)
– Batteries store power for use during the eclipse
phase of the station’s orbit
IEA (continued)
• Direct Current Switching Unit (DCSU)
– Routes power from BGA to batteries, IEA, and
Internal system
• Direct current to Direct current Converter
Unit (DDCU)
– Provides Secondary power for all components.
IEA Thermal control system
• IEA has a self contained thermal control system
for each channel
• Small radiators under each IEA dissipate heat
from the SSU as well as batteries and other IEA
components
• This system functions in the same manner as the
main TCS for the station
• Pump and Flow Control Subassembly (PFCS) and
Photovoltaic Radiator (PVR)
ECU/SSU
• Electronic Control Unit
– Manages when to charge and discharge the
batteries
• Sequential Shunt Unit
– Shunts any excess power generated as heat
– Small radiator beneath each PVA radiates heat
Grounding
• To prevent electricity from arcing across the
station all electrical devices are grounded to
the main truss.
• Plasma Contractor Unit (PCU)
– Emits a stream of plasma to ground the space
station’s main truss to space
– Prevents arcing to any external spacecraft
during docking or EVA
BGA/PVA
• Beta Gimbal Assembly
– Rotates one channel of power per BGA
– Controls rotation perpendicular to the main
station truss
• Photovoltaic Array
– Collects sunlight and converts it into electrical
power
Warning Signs of a SOBE
• Red indicator light on the system wall
• Loss of Power (I.e. lights or computer
unexpectedly shut down)
• Warning through HAL or other system
• Contingency of another SOBE
Things to check during a SOBE
• For maximum power the panels must be
perpendicular to the sunlight, if misaligned
they may not produce enough power
• There are many points were power can be
stopped, be sure to check them all