Electrical Power Subsystem Research Articles

Enhanced hybrid energy storage system combining battery and supercapacitor to extend nanosatellite lifespan

The power limitations of nanosatellites, particularly during peak demand periods such as data transmission and maneuvering, hinder their operational capabilities. Traditional Electrical Power Subsystems relying solely on batteries face challenges in delivering the necessary power density and maintaining battery life, especially during eclipses. This study proposes an innovative Hybrid Energy Storage System for a 3U nanosatellite, integrating high-energy-density batteries with high-power-density supercapacitors, using an active parallel hybrid topology with two bidirectional converters and an optimal power management strategy. Using MATLAB and Simulink models, the study optimizes the Hybrid Energy Storage System by focusing on minimizing the capacity rate and depth of discharge to extend battery life. Simulation results show a 53.42% reduction in depth of discharge compared to a battery-only system, indicating a significant extension of battery life. Additionally, the proposed system allows for a minimal 2.08% increase in overall mass while maintaining enhanced performance. This research fills a critical gap in the literature by exploring active Hybrid Energy Storage System topologies for spacecraft applications, beyond the traditional passive and semi-active configurations. The innovative power management strategy ensures efficient energy utilization, significantly enhancing the reliability and efficiency of nanosatellite missions. The findings offer a practical solution to improve mission performance and extend the operational lifespan of nanosatellites, paving the way for more robust and capable small satellite deployments.

Spacecraft fault detection and identification techniques using artificial intelligence

The complexity of spacecraft systems and their missions is increasing, requiring higher levels of performance and innovative solutions. It is essential to have onboard autonomy with minimal faults to ensure reliability, availability, and safety. Fault Detection and Identification (FDI) is critical in identifying spacecraft faults before they cause major failures. However, FDI design and application are challenging due to the space environment and the reliance on system information. To improve accuracy, speed, and noise robustness, modern FDI methods based on Artificial Intelligence (AI) techniques have been developed. This paper investigates the latest FDI techniques in the spacecraft attitude determination and control subsystem (ADCS) and electrical power subsystem (EPS). The article discusses various FDI methodologies and frameworks, highlighting their advantages, drawbacks, and the significance of AI implementation. Additionally, the paper presents a thorough analysis and comparison of the different methods.

Analytical modelling and sizing of supercapacitors for spacecraft hybrid energy storage systems

The vast majority of Earth-orbiting satellites carry an electrical power subsystem (EPS) which main components are solar panels and secondary batteries. During eclipse periods, satellites are powered only by rechargeable batteries which have a large energy density but a limited power density. This fact limits the power capabilities of small satellites during eclipse periods. Due to the large power density of Supercapacitors (SCs), ground and on-orbit tests have been conducted to verify their applicability on satellite EPSs. At the moment, no studies are underway on the issue of sizing SCs for eclipse operations. Hybrid configuration could reduce the mass and volume of EPS or maintain those reference values but increasing peak power capabilities. This paper deals with this issue. On the one hand, novel analytical expressions of a variable capacitance SCs are derived, including time–voltage dependence in constant power applications. Also an equivalent formulation for a SCs bank (SCsB) is derived. On the other hand, a SCsB sizing procedure is presented, considering the energy and power requirements of a particular space mission as an input. Finally, a simple mission is analysed, the results showing an improvement on the hybrid EPS design with respect to the traditional, being the mass reduction of 36%.

New Sizing Methodology and Efficiency Analysis of Satellite’s Electrical Power Subsystem

This paper describes a novel methodology to improve the preliminary design and efficiency analysis of the satellite’s electrical power subsystem. Several studies have addressed this issue by proposing a solar array sizing method based on the use of fixed efficiency paths during sunlight and eclipse periods. Indeed, these studies restrict the use of the battery for eclipse periods, and thus the solar array is sized to support the peak power loads on its own. To the authors’ knowledge, no one has so far deeply and jointly analyzed the influence of the power profile demand, the use of the battery during sunlight periods, and the architecture on the efficiency paths to size the electrical power subsystem. This work offers a methodology that takes into account these variables to better estimate the global efficiency of the electrical power subsystem and, consequently, to refine the first design iterations of a satellite. This methodology is particularized for the most common architectures based on power and voltage bus regulation, although it can be implemented in more complex architectures. A case study involving a real space mission, the UPMSat-2 (a 50 kg satellite launched in September 2020), is conducted to test this methodology.

The Application of Machine learning to Amazonia-1 satellite power subsystem telemetry prediction

This article presents the data acquisition, exploratory data analysis, model training, evaluation, and use of hyperparameters in a machine learning model that will be used to predict telemetry data from the Amazonia-1 satellite. The Amazonia-1 satellite was launched in 2021, it uses the Multi-Mission Platform as a service module and has a Wide Field Imager imaging camera. Its power subsystem has 715 telemetries with distinct data types that will be used as dependent and independent variables. The amount of telemetry data generated daily is large, making manual analysis of this data unfeasible. The ensemble XGBoost machine learning algorithm is used to predict the values of the dependent variable D008 “Battery Module 1 Voltage” that belongs to the electric power subsystem. For the evaluation and performance Mean Absolute Error (MAE), Root Mean Square Error (RMSE), and R2 are used. The final learning model resulted in the coefficient of determination (R2) with 99.99%, MAE of 0.005749, and RMSE of 0.007727. After the cross-validation step, RMSE reached 0.006888. The execution time was 57 minutes and 32 seconds. Based on these numbers, we can consider that the machine learning model built reached a good result, especially when used with cross-validation.

Proposal of rectennas as an auxiliary device for the electrical power subsystem of a 1U CubeSat

Current electrical power subsystem (EPS) devices operate solely on solar panels and batteries, depending on them to provide at least 5 watts of power for a 1U CubeSat, this research proposes an auxiliary method to increase the CubeSat power or lessen the battery sizes by providing a different energy source via a rectenna. These devices are capable of delivering an output voltage by harnessing electromagnetic waves in its surroundings, there are different types of circuits and this paper compiles the best candidates to operate in a 1U CubeSat. Nanosatellites are strongly restricted by their weight and energy usage, thus by using an auxiliary device for the EPS that could potentially reduce the size of said subsystem, the results are an even more efficient CubeSat in terms of energy and space distribution.

Bench satellite development and testing

This paper discusses the development of a satellite-like system to bridge the gap between satellite development and satellite flight missions. The solution takes the form of a bench satellite, BenchSat, that can emulate satellite capabilities and interactions in a controlled environment on the ground. BenchSat utilises surrounding facilities, particularly an air bearing facility and an existing ground station, to produce a realistic test environment for satellite development. The air bearing facility entails a cart with pressurised gas which pushes the cart on a flat surface, creating a low-friction, space like environment. BenchSat comprises an electrical power subsystem, a radio communication subsystem, and an onboard computer subsystem. These systems are created to be a good representation of equivalent flight models and can serve as an initial step in the future development of each of these subsystems. A final experiment was conducted using an integrated BenchSat connected to an air bearing carrier cart. The ground station was used to give commands to the BenchSat to use its thrusters to translate and rotate the carrier cart. This creates a realistic interface to perform satellite rendezvous experiments. It is further extended to interface with a satellite simulator for Hardware-In-Loop testing and flight software development.

Improvement of Application Efficiency for Li-Ion Batteries Used in the Satellite Electric Power Subsystems

Improvement of Application Efficiency for Li-Ion Batteries Used in the Satellite Electric Power Subsystems

On the modeling and simulation of a stratospheric experiment power subsystem

This paper describes an accurate model of the Electrical Power Subsystem (EPS) of the Thermal Analysis Support and Environment Characterization Laboratory (TASEC-Lab), a university experiment developed for using in high-altitude balloon missions to measure and analyze the convection heat transfer. A Li-ion battery and two high efficient DC–DC converters have been characterized through laboratory tests and fitting to the experimental results. The developed mathematical models described in this paper are used to carry out accurate EPS simulations and are validated by comparison with the experimental data.

TASEC-Lab: A COTS-based CubeSat-like university experiment for characterizing the convective heat transfer in stratospheric balloon missions

The Thermal Analysis Support and Environment Characterization Laboratory (TASEC-Lab) is an experiment designed, integrated, and tested in the Universidad Politécnica de Madrid by bachelor's, master's and doctoral students. The aim of this project is to study the convection heat transfer, the thermal environment and the balloon dynamics during the ascent and float phases of a stratospheric balloon launched from the León (Spain) airfield on 16th, July 2021. TASEC-Lab has been designed following the CubeSat philosophy using commercial off-the-shelf (COTS) components. It consists of an aluminium structure of 130 × 130 × 330 mm3 with three compartments where the Electrical Power Subsystem, the Electronics, and the Heat Transfer Laboratory, are located. In addition, it carries a cup anemometer to be tested at the low-pressure conditions at high altitude to provide the relative speed of the balloon-gondola system in order to characterize the dynamics and the forced convection heat transfer. In this paper, the TASEC-Lab design is detailed as well as the different development phases considered in a university environment where all tasks were carried out by students, with the technical support of the research staff of the Instituto Universitario de Microgravedad “Ignacio da Riva” (IDR) and the group of Sistemas de Tiempo Real y Arquitectura de Servicios Telemáticos (STRAST).

Lessons Learned from IDEASSat: Design, Testing, on Orbit Operations, and Anomaly Analysis of a First University CubeSat Intended for Ionospheric Science

Given the pervasive use of satellite and over the horizon wireless communication technology in modern society, ionospheric disturbances that can disrupt such services are a crucial consideration. Ionospheric irregularities, plasma bubbles and other phenomena can have a great impact on satellite navigation and communications, impacting other systems reliant on such technologies. The Ionospheric Dynamics and Attitude Subsystem Satellite (IDEASSat) was a 3U developed by National Central University (NCU) to measure irregularities in the ionosphere, as well as to establish spacecraft engineering and operations capacity at NCU. The onboard Compact Ionospheric Probe (CIP) could measure high-resolution plasma parameters, which can be used for identifying ionospheric irregularities that can cause scintillation in satellite navigation and communications signals. Part of the spacecraft sub-systems were independently designed and developed by students, who were also responsible for integration, testing, and operations. IDEASSat was successfully launched into low Earth orbit on 24 January 2021, and then began mission operations. The spacecraft successfully demonstrated three-axis attitude stabilization and control, tracking, telemetry and command (TT&C), as well as flight software and ground systems that could support autonomous operation. The spacecraft experienced a critical anomaly 22 days after launch, followed by a 1.5-month communications blackout. The spacecraft briefly recovered from the blackout for long enough to replay flight data, which allowed for the cause of the blackout to be determined as an inability of the electrical power subsystem reset circuit to recover from an ionizing radiation induced single event latch-up. Although the mission was not completed, flight data obtained during the mission will help to improve the designs of future spacecraft in development at NCU. This paper will introduce IDEASSat’s final flight model design and implementation, integration, testing, environmental verification, and failure analysis, and will review the performance of the spacecraft during on-orbit operations. The results and experiences encountered in implementation and operations of the IDEASSat mission are presented here as a reference for other university small satellite teams.

Mathematical Modelling of Transient Processes in a Three Phase Electric Power System for a Single Phase Short-Circuit

Field approaches are employed to develop a mathematical model of a power network section. The facility consists of two electric power subsystems described with ordinary differential equations and presented as concentrated parameter systems connected with a three-phase power supply line, presented as a distributed parameter system. The model of the electric power line is described with partial differential equations. Mathematically, the supply line model is described utilizing a mixed problem with explicitly indefinite boundary conditions. All electromagnetic state equations of the integrated system are introduced in their matrix-vector forms. The equation of the three-phase long supply line is expressed untraditionally as a system of two first-order differential equations as a function of long line voltage. Since the power supply line is part of the integrated system that includes two subsystems, the boundary conditions at the line’s start and end are implicitly defined, avoiding the traditional application of the Dirichlet first-type boundary condition. An expanded system of ordinary differential equations that describe physical processes in both the supply and loading subsystems is used to calculate the boundary conditions. To this end, third-type boundary conditions, or Poincaré’s conditions, serve to describe the wave equation of the electric power line. Such an integrated model of an electric power system helps analyse transient processes across the supply line when the electric power system is switched on and is single-phase short-circuited at the final point of the electric power line. A comparison of computer simulation results with well-known software packages shows a convergence of approx. 96%.

A Spacecraft Attitude Determination and Control Algorithm for Solar Arrays Pointing Leveraging Sun Angle and Angular Rates Measurements

The capability to orient the solar arrays of a spacecraft toward the Sun is an ultimate asset for any attitude determination and control subsystem (ADCS). This ability should be maintained in any operative circumstance, either nominal or off-nominal, to avoid the loss of the entire space-borne system. The safe mode implementation should guarantee a positive power generation from the solar arrays, regardless of the health status of the satellite platform. This paper presents a solar array pointing algorithm, to be executed on-board, with a minimal set of sensors and actuators. In fact, the sensors are limited to the solar arrays, exploiting the current/voltage sensing capacity of the electrical power subsystem to measure the Sun angle with respect to the arrays normal, and to the angular rates sensors. The actuators are required to provide a torque only along two axes and, thus, a reduced actuation capacity is still manageable by the proposed algorithm. The paper describes the algorithm, both in the Sun direction determination and in the Sun pointing control capacity. The achieved performance is outlined, considering either an ideal system or a realistic one, being the latter affected by sensors and actuators limitations. The actuation by means of momentum exchange devices or magnetic torquers is discussed, with the purpose to prove the wide applicability range of the presented algorithm, which is capable to guarantee solar array orientation with a minimal hardware set.

Design and first simulations of the TASEC-Lab power subsystem

This paper describes the modelling and simulation of the Electrical Power Subsystem (EPS) of the Thermal Analysis Support and Environment Characterization Laboratory (TASEC-Lab). TASEC-Lab is a university experiment on board a sub-orbital platform. It is designed to measure the convection heat transfer in high-altitude balloon missions. The EPS provides, regulates, and distributes electric power to the different systems, parts, and sensors that compose the TASEC-Lab (e.g., On Board Computer (OBC), temperature and pressure sensors, cup anemometer, GPS, heaters... ). It mainly consists of a Li-ion battery and two DC-DC converters, and they have been characterized by conducting laboratory tests and fitting to experimental data. A real power consumption profile of the first TASEC-Lab’s mission (designed by Universidad Politecnica de Madrid) is used as input to simulate the EPS. The mathematical model is validated by comparison with experimental results.

Single event latch-up detection for nano-satellite external solar radiation mitigation system

This paper presents the single event latch-up (SEL) detection for nano-satellite external solar radiation mitigation system. In this study, the SEL detection analysis was conducted using circuit test and simulation. An electrical power subsystem (EPS) is a part of all CubeSat bus subsystems and it comprises solar arrays, rechargeable batteries, and a power control and distribution unit (PCDU). In order to extract the maximum power generated by the solar arrays, a peak power tracking topology is required. This may lead to the SEL with the presence of high voltage produced by solar. To overcome the SEL problems, the circuit test and simulation must be done so that the flow of SEL will be easily detected and mitigate. The method that been used are by using microcontroller, the SEL will be created in the certain time. The programable integrated circuit (PIC) are used to mitigate SEL effect. It indicates that, the SEL occur very fast in certain time. When the simulation is conducted by using SPENVIS, the result shows, only single event upset (SEU) was affected on UiTMSAT-1.

A Simple Power Source Modeling and Experimental Investigation of a Spacecraft for EMC Applications

Simplified modeling of a spacecraft power system is proposed to predict the conducted electromagnetic compatibility (EMC) environment. A key element of the spacecraft conducted environment is the electrical power subsystem, which corresponds to the power source. Since the impedance of the power source has a significant effect on conducted interference, the assessment of power bus impedance is essential to control and manage spacecraft EMC. In the proposed model, all components inside the power system were modeled as simple equivalent circuits with lumped elements. The advantage is that it simplifies the complex power system so that its impedance can be quickly obtained at the early stage of spacecraft system design and development. The model is validated by comparing the calculated results with experimental data. The comparison results between simulation and experiment showed good agreements.

System Analysis and Design of the Geostationary Earth Orbit All-Electric Communication Satellites

With the help of gathered data and formulas extracted from a previous conference paper, the all-electric geostationary Earth orbit (GEO) communication satellite statistical design was conducted and further studied with analytic hierarchy process (AHP) and technique for order of preference by similarity to ideal solution (TOPSIS) methods. Moreover, with the help of previously determined system parameters, the orbital ascension, orbital maintenance and deorbiting specifications, calculations and simulations were persuaded. Furthermore, a parametric subsystem design was conducted to test the methods reliability and prove the feasibility of such approach. The parametric subsystem design was used for electrical power subsystem (EPS), attitude determination and control system (ADCS), electric propulsion, telemetry, tracking and control (TT&C) in conceptual subsystem design level, which highly relies on the satellite type and other specifications, were concluded in this paper; other subsystem designs were not of a significant difference to hybrid and chemical satellites. Eventually, the verification of the mentioned subsystems has been evaluated by contrasting the results with the Space mission engineering: the new SMAD, and subsystem design book reference.

A novel concept of cost-effective active debris removal spacecraft system

Post Mission Disposal (PMD) alone is an insufficient solution to stabilize the orbital debris environment, but combining Active Debris Removal (ADR) with PMD and other means of debris mitigation is considered a promising remediation method. The cost reduction of ADR is essential to make it a sustainable business. The major cost driver of ADR is the ADR spacecraft and its launcher, both of which are largely influenced by the spacecraft size. A trade-off study of the ADR spacecraft system has been conducted to minimize its size, resulting in the novel concept of a cost-effective ADR spacecraft system. The authors introduce the combination of electric propulsion (EP) and air drag utilization for the debris deorbit phase so as to lower the EP requirement, thereby leading to cost reduction of the ADR spacecraft. The minimum delta-V reentry method is also considered to reduce the propellant mass for final reentry. EP performance (e.g. thrust, specific impulse, mass) is modeled as a function of power consumption, and optimum EP performance has been explored to minimize overall mass of the ADR spacecraft, including its electrical power subsystem with this EP model. Given the minimum thrust limit to satisfy the mission duration requirement, a higher thrust-to-power ratio is preferable for debris removal electric propulsion. This paper discusses the optimal EP performance requirements in detail, and the results show that a roughly 500-kg ADR satellite using a 600-W-class Hall thruster can remove about three tons of a rocket body debris from an 800-km circular orbit within 600 days.

Comprehensive design and control methodology for DC‐powered satellite electrical subsystem based on PV and battery

The design of electrical power subsystem of a satellite is challenging since it involves many components and depends on multiple parameters including mission duration, satellite orbit, eclipse times and etc. In contrast to the existing mission specific designs, we propose a generalized and comprehensive method to design and size key EPS elements: PV array and battery, which are integral for mission success. For battery, the proposed design incorporates battery cell characteristics, round trip efficiency, degradation, eclipse load profile and operating modes. The proposed design of PV array takes into account orbit inclination and altitude. In addition, structure and geometry of PV array are also considered and used for irradiance forecasting. Reliability, power margins and power fraction for summer solstice are also factored in the design. For the planning and development of operational strategy, parameter limits are determined for depth of discharge, initial state-of-charge, final state-of-charge and end-of-charge voltage of the battery. The controller design is also presented for the EPS. The effectiveness of the proposed design methodology is verified by a case study of Mysat-1, an imaging nanosatellite developed and launched by Khalifa University.

Benchmark model for multi‐orbital transient analysis of satellite electrical power subsystem

In this study, an efficient multi-orbital simulation model is presented for satellite Electrical Power Subsystem (EPS) which is integral to the success of the mission. The model integrates converter models, PV array model, DC bus model, and a numerical battery model according to a generalised EPS architecture to form one unified model of the entire EPS. The proposed model reduces simulation complexity, enhances speed, and enables multi-orbit analysis capability. Dynamic interaction among the elements is modelled through a coordinated control containing maximum power point tracking (MPPT), voltage regulation, battery charge/discharge control and management. Practical concerns of digital control implementation for PI controllers and MPPT are also incorporated in the model. Anti-windup is implemented to avoid latency in controller action after the eclipse. Additionally, a robust MPPT algorithm ensures fast immediate action after eclipse. Efficient component models and practical attention-to-detail enable the developed model to simulate multiple orbits with eclipse periods. The superior speed of the model, ability to simulate multiple orbits, and test different control strategies are demonstrated with a practical case study of Mysat-1, an imaging satellite launched by the Khalifa University. The model can be used as a proof-of-concept tool for predicting the operational behaviour of EPS during the development of a satellite.