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6 Power Technology of Lunar Lander
6.4.6 Analysis of Power System Architecture
1. Distribution and Grounding System
The power system of the Chang’E-3 lunar lander provided a fully regulated main
bus, which was used by the power distribution unit to provide primary power for the
instruments. Secondary power supply could be provided according to requirements
by distributor for secondary distribution.
Compared with conventional spacecraft, the interface design of the Chang’E-3
lunar lander was more complex in grounding [12]. The probe consisted of the lunar
lander and the lunar rover, while the complex worked together sometime and the
lunar lander or the lunar rover worked separately sometime. In grounding design of
the lunar lander, it was necessary to meet the single-point grounding requirement
during flight alone, as well as the single-point grounding requirement during flight
in the complex status. The lunar lander and the lunar rover respectively set a single
point of grounding point within the respective power distribution unit, and the two
probes was connected electrically with a high resistor. Before the lunar lander was
landed of lunar surface, the rover was considered as an electrical load of the lunar
lander. Single grounding was achieved respectively for each probe after landing.
2. Power Supply System
According to task characteristics and requirements of the power system, the power
system consisted of solar arrays, power controllers and battery packs.
Compared to silicon solar cells and single-junction gallium arsenide solar cells, the
triple-junction gallium arsenide solar cell has the advantages of high photoelectric
conversion efficiency and high area specific power, which becomes the preferred
main power source for various types of spacecraft in the world. Considering power
requirement and mass constraint, the triple-junction gallium arsenide solar cell was
used as a power generation unit in power system.
Compared to nickel-cadmium and nickel-hydrogen batteries, lithium ion battery
has the advantages of high specific energy, high cell voltage, wide operating temperature range, low heat generation, and low self-discharge rate. Due to the constraints of
mass and volume, lithium-ion battery pack was used as energy storage after the power
density and low self-discharge rate requirements during lunar night was considered.
The S4R power regulation technology was used the power controller. The S4R
power regulation technology combined the advantages of S3R-type and hybrid-type
power regulation technologies. It implemented two-domain control, which not only
overcame the disadvantages of the three-domain complicated control of the S3R
power regulation technology, and the large power consumption and mass of the
charging controller, but also avoided the disadvantages of low energy utilization of
the solar array induced by the separate design of the charging array in the hybrid
power adjustment technology.
For the task requirements of autonomous hibernation and wake-up of the lunar
lander, a wake-up control circuit was separately designed in the power controller,
which was responsible for the transfer of operation modes in lunar daytime and lunar
6 Power Technology of Lunar Lander
6.4.6 Analysis of Power System Architecture
1. Distribution and Grounding System
The power system of the Chang’E-3 lunar lander provided a fully regulated main
bus, which was used by the power distribution unit to provide primary power for the
instruments. Secondary power supply could be provided according to requirements
by distributor for secondary distribution.
Compared with conventional spacecraft, the interface design of the Chang’E-3
lunar lander was more complex in grounding [12]. The probe consisted of the lunar
lander and the lunar rover, while the complex worked together sometime and the
lunar lander or the lunar rover worked separately sometime. In grounding design of
the lunar lander, it was necessary to meet the single-point grounding requirement
during flight alone, as well as the single-point grounding requirement during flight
in the complex status. The lunar lander and the lunar rover respectively set a single
point of grounding point within the respective power distribution unit, and the two
probes was connected electrically with a high resistor. Before the lunar lander was
landed of lunar surface, the rover was considered as an electrical load of the lunar
lander. Single grounding was achieved respectively for each probe after landing.
2. Power Supply System
According to task characteristics and requirements of the power system, the power
system consisted of solar arrays, power controllers and battery packs.
Compared to silicon solar cells and single-junction gallium arsenide solar cells, the
triple-junction gallium arsenide solar cell has the advantages of high photoelectric
conversion efficiency and high area specific power, which becomes the preferred
main power source for various types of spacecraft in the world. Considering power
requirement and mass constraint, the triple-junction gallium arsenide solar cell was
used as a power generation unit in power system.
Compared to nickel-cadmium and nickel-hydrogen batteries, lithium ion battery
has the advantages of high specific energy, high cell voltage, wide operating temperature range, low heat generation, and low self-discharge rate. Due to the constraints of
mass and volume, lithium-ion battery pack was used as energy storage after the power
density and low self-discharge rate requirements during lunar night was considered.
The S4R power regulation technology was used the power controller. The S4R
power regulation technology combined the advantages of S3R-type and hybrid-type
power regulation technologies. It implemented two-domain control, which not only
overcame the disadvantages of the three-domain complicated control of the S3R
power regulation technology, and the large power consumption and mass of the
charging controller, but also avoided the disadvantages of low energy utilization of
the solar array induced by the separate design of the charging array in the hybrid
power adjustment technology.
For the task requirements of autonomous hibernation and wake-up of the lunar
lander, a wake-up control circuit was separately designed in the power controller,
which was responsible for the transfer of operation modes in lunar daytime and lunar