What are the components of the onboard power system?

What are the components of the onboard power system?

The onboard power system has three different components, namely the battery, the solar cell array and the voltage regulation circuit. The key devices and circuits used in these three components are clearly shown in Figure 1.

What are the components of the onboard power system?
Figure 1 The concept of controlled and uncontrolled power buses for potential applications such as satellite power systems

1. Power bus design configuration
There are two types of power bus configuration, namely a controlled power bus configuration and an uncontrolled power bus configuration. In the case of a controlled bus, a booster element and a switch control diode provide voltage regulation. In the case of an uncontrolled bus configuration, a pre-regulated electrical load is installed, thereby avoiding the need for a separate control element. In the case of complex covert reconnaissance and surveillance satellite applications, if ultra-high reliability and a long satellite operating life of more than 10 years are design requirements, a redundant power supply system is necessary.

2. Solar array panel
The requirements of solar cells and solar cell arrays strictly depend on continuous power consumption; depending on the working life of the satellite, an additional 30%-40% of power is required to meet the power consumption requirements. The power changes of typical solar cell arrays in space-based satellites are summarized in Table 1.

Working life/yearPower output/WReduced power level/%
0 (after launch)650100
158393.5
255890.2
354387.6
451783.4
550080.6
645573.4
738962.7
834255.2
Table 1 Changes in the output power of a typical satellite solar array

In space and satellite-based systems, batteries generally experience power changes and degradation over life. For a typical space-based battery, the output power of the battery after 8 years is reduced to 55.2% of the original value, as shown in Figure 2. This is a well-designed and sealed space-based maintenance-free battery. The performance of some batteries may last a little longer or a little shorter time, depending on the efficiency of the electrochemical reaction and the working space environment. If the battery is inside the satellite structure, the influence of space radiation on the power performance of the battery is negligible.

What are the components of the onboard power system?
Figure 2 The power of satellite-based solar array panels varies with the duration of service

The performance requirements of solar cell arrays that charge space-based batteries. The installation of solar cell arrays is necessary to charge the airborne batteries. The latter are various electronic equipment, stability and attitude control sensors, space parameter monitors, lighting and many other performances required to maintain the satellite or spacecraft within the scheduled mission period. The vital electrical system provides power.

The schematic diagram of the orbital characteristics and the position of the solar cell array on the rotating satellite is shown in Figure 3. The charging frequency of the battery on a communication satellite or a surveillance and reconnaissance satellite strictly depends on the requirements of the wire. The importance of the electrical load of communication satellites is moderate compared with that of surveillance and reconnaissance satellites. Reconnaissance and surveillance satellites have several microwave, photoelectric, optical, and infrared sensors, such as high-definition side-viewing radar, precise laser tracking sensor, high-resolution infrared camera, high-speed digital computer with ultra-high computing power, and other climate parameters Monitoring equipment. In addition, the reconnaissance and surveillance satellites will be equipped with a large number of solar cell arrays to meet the high power load requirements of the main sensors and the power supply requirements of the power supply redundancy system to meet the reliability and expected mission objectives.

What are the components of the onboard power system?
Figure 3 Design configuration of solar cell array