Spacecraft Power System Research Articles

Artificial Intelligence Techniques for Controlling Spacecraft Power System

Advancements in the field of artificial intelligence (AI) made during this decade have forever changed the way we look at automating spacecraft subsystems including the electrical power system. AI have been used to solve complicated practical problems in various areas and are becoming more and more popular nowadays. In this paper, a mathematical modeling and MATLAB–SIMULINK model for the different components of the spacecraft power system is presented. Also, a control system, which includes either the Neural Network Controller (NNC) or the Fuzzy Logic Controller (FLC) is developed for achieving the coordination between the components of spacecraft power system as well as control the energy flows. The performance of the spacecraft power system is evaluated by comparing two control systems using the NNC and the FLC.

A Hybrid Data Preprocessing-Based Hierarchical Attention BiLSTM Network for Remaining Useful Life Prediction of Spacecraft Lithium-Ion Batteries.

As a crucial energy storage for the spacecraft power system, lithium-ion batteries degradation mechanisms are complex and involved with external environmental perturbations. Hence, effective remaining useful life (RUL) prediction and model reliability assessment confronts considerable obstacles. This article develops a new RUL prediction method for spacecraft lithium-ion batteries, where a hybrid data preprocessing-based deep learning model is proposed. First, to improve the correlation between battery capacity and features, the empirically selected high-dimensional features are linearized by using the Box-Cox transformation and then denoised via the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) method. Second, the principal component analysis (PCA) algorithm is employed to perform feature dimensionality reduction, and the output of PCA is further processed by the sliding window technique. Third, a multiscale hierarchical attention bi-directional long short-term memory (MHA-BiLSTM) model is constructed to estimate the capacity in future cycles. Specifically, the MHA-BiLSTM model can predict the RUL of lithium-ion batteries by considering the correlation and significance of each cycle's information during the degradation process on different scales. Finally, the proposed method is validated based on multiple types of experiments under two lithium-ion battery datasets, demonstrating its superior performance in terms of feature extraction and multidimensional time series prediction.

Fault Detection and Diagnosis in Spacecraft Electrical Power Systems

The ability to accurately identify and isolate failures in the electrical power system (EPS) is critical to ensure the reliability of spacecraft. This paper proposes a novel solution to the problem of fault detection and diagnosis in direct current (DC) electric power systems for spacecraft. Autonomous operation becomes essential during deep space missions that lack the ability to monitor and control the spacecraft from ground locations. The current state of EPS fault supervision is insufficient to guarantee highly reliable operation. To solve this issue, a combination of model-based and knowledge-based techniques are used in a hierarchical framework to improve the diagnostic performance of the system. Noise, disturbances, and modeling errors are considered in the design of the fault detection system. Practical considerations related to spacecraft flight hardware and software are accounted for in the system design for flight applications. To assess the functionality of the design, a wide array of failures are simulated in a series of experiments. The experiments showed that the technique improved the capability of the autonomous system by increasing the number of fault types diagnosed. The significance of this study is to provide a framework capable of advanced diagnostics of an EPS with little to no interaction from human operators.

Study of the Within-Batch TID Response Variability on Silicon-Based VDMOS Devices

Silicon-based vertical double-diffused MOSFET (VDMOS) devices are important components of the power system of spacecraft. However, VDMOS is sensitive to the total ionizing dose (TID) effect and may have TID response variability. The within-batch TID response variability on silicon-based VDMOS devices is studied by the 60Co gamma-ray irradiation experiment in this paper. The variations in device parameters after irradiation is obtained, and the damage mechanism is revealed. Experimental results show that the standard deviations of threshold voltage, subthreshold swing, output capacitance, and diode forward voltage increase, while the standard deviation of maximum transconductance decreases after irradiation. The standard deviation of on-state resistance is basically unchanged before and after irradiation. By separating the trapped charges generated by TID irradiation, it is found that the deviation of the oxide trapped charges and the interface traps increase with the increase in the total dose. The reasons for the variation in device parameters after irradiation are revealed by establishing the relationship between the trapped charges and the electrical parameters before and after irradiation.

Powder feeding enhancement of powder propellant supply system by using gas-permeable piston

Stable and efficient powder propellant feeding is the key to the excellent performance of powder engines, but the previous structures of supply systems pose a challenge to it. Therefore, structural optimization has been made for the powder propellant supply system to promote feeding. Specifically, the traditional sealed piston is optimized as the gas-permeable piston that has an annular gap between the piston edge and the silo wall to allow the driving gas to permeate into the powder column, producing the gas pressure gradient to increase powder axial pressure and leading to the cancellation of fluidization gas line at the front of the silo to reduce gas turbulence and powder fluctuations. There is a discovery that the powder achieves mass flow under only airflow and discharged powder amount can be maximized as much as possible by combining with gas-permeable piston, which also supports the feasibility of the optimized system and realizes a more stable and higher flux flow. In addition, the gas-permeable piston with a gear-shaped end face has the best overall performance. Through this work, we wish that our research can provide valuable guidance for the design of powder propellant supply systems to meet the requirements of spacecraft power systems.

A Fault-Tolerant Strategy for Three-Level Flying-Capacitor DC/DC Converter in Spacecraft Power System

With the development of space exploration, high-power and high-voltage power systems are essential for future spacecraft applications. Because of the effects of space radiation such as single event burnout (SEB), the rated voltage of power devices in converters for a spacecraft power system is limited to a level much lower than that for traditional ground applications. Thus, multi-level DC/DC converters are good choices for high-voltage applications in spacecraft. In this paper, a fault-tolerant strategy is proposed for a three-level flying capacitor DC/DC converter to increase the reliability with minimal cost. There is no extra hardware needed for the proposed strategy; the fault tolerance of the converter is only achieved by changing the software control strategy. A stage analysis of the proposed strategy is provided in detail for different fault locations and ratios between the input and output voltage. Finally, a simulation model and prototype are built to verify the effectiveness of the proposed strategy.

Tests of the disk intake device of a droplet refrigerator-emitter with blocking of reflected flows and optimization of the design

The results of tests of the intake device of the droplet refrigerator of the emitter of the thermal stabilization system of spacecraft power systems using droplet monodisperse flows are presented. Design optimization based on them is proposed. Keywords droplet refrigerator-emitter, thermal control of energy systems, cooling of spacecraft power plants

Cube Satellite Battery Charger Regulator Design

Battery Charger Regulator (BCR) circuit used on spacecraft power systems, are usually switching regulators to provide maximum power for current operation mode and fixed voltage for voltage mode. In this article, we present detailed design procedures for BCR implemented on Cube-satellite. We will show small-signal analysis of a battery charger, to perform the control loop design of the maximum power point detection step and also voltage mode control loop to detecte battery Endof- charge. We present also a simulation of tow loops to verify our design.

Research on Three-Port Converter for New Aerospace Energy Architecture

The traditional design method of spacecraft power systems based on customization and the combination of two-port converters can no longer meet the increasing application demands of having high power and being modular and versatile. Three-port DC converter, standardized to form a redundant parallel power supply system with a distributed model, is a possible solution to meet the design requirements of the above spacecraft power supply system. In this paper, a three-port converter is designed to complete the MPPT control of the PV array at the input end to maximize the power generated by the PV array, complete the battery charge and discharge control, realize the bidirectional conversion and transmission of the battery charge and discharge power, and complete the control of the load voltage at the output end to ensure the stable and reliable power supply of the load. If the integrated DC converter is used to realize the power transmission and conversion between the three ports at the same time, the volume and weight of the system can be greatly reduced, and then the power density of the system can be improved.

An Analog-Device-Based Five-Domain Control Method and Distributed System Configuration for High-Power Spacecraft Power Systems

Deep space exploration is gaining increasing interest as the space station and lunar base projects are putting on the agenda. Due to the limited power level of the power controlling unit (PCU), high-power space power systems have to be constructed with several PCUs, forming a PCU interconnection system. However, the existing control methods and architectures are either unsuitable for systems with more than two PCUs or must be implemented with the digital controller, which is rarely used in space power systems due to the single-event upset (SEU). In this article, a communication-free distributed configuration for PCU interconnection system and a novel analog-device-based five-domain control method are proposed. Detailed control strategies and five working modes of the PCU subsystem are analyzed. Seamless switch during mode transition is realized by designing control parameters carefully, which ensures the stability of the PCU bus voltage. A three-PCU interconnection system is constructed, and both steady-state and dynamic responses of the system are tested, validating the effectiveness of the proposed control method.

Development of the methodological approaches for the attitude control system of the Earth remote sensing satellite in the conditions of the onboard equipment partial failures

The spacecraft controllability of the angular motion is possible only with operability of the attitude and orbit control system (AOCS) of the spacecraft, sensors, actuators and the spacecraft power system. However, there is a rather significant probability of failure of this equipment during the operation of the spacecraft. This is especially observed after half of the spacecraft's lifetime or because of emergency situations. There is a problem which is connected with providing the maximum performance of the AOCS in case of partial failures of their actuators (reaction wheels (RW), magnetorquer rods (MGTR), etc.).
 Thus, the purpose of this work is the development and synthesis of special algorithms for spacecraft angular motion control in the emergency situations which are connected with RWs partial failures and restrictions of onboard electricity consumption. The approach of synthesis of this control algorithms is based on using mobile control methods which allow to reserve RWs by MGTRs. There are different variants of control loops depending on MGTRs turning on combinations. There were proposed two types of control switching functions: time-periodic and switching by deviation. Also was proposed a methodology of controller synthesis using these switching functions.
 Using this methodology and computer simulation, it was shown the possibility of providing angular nadir orientation and stabilization of the spacecraft with maximum 1−1.5 deg error in case of time-periodic switching functions implementation. Switching by deviation allows to reduce onboard electricity consumption for 25−30 % comparing with using time-periodic switching. However, the accuracy of stabilization significantly lower in case of switching by deviation. Considering these estimates, the corresponding methodological recommendations were formulated for use switching functions depending on emergency

Substantiation for the selection of parameters for ensuring electrothermal protection of solar batteries in spacecraft power systems

A relevant scientific-practical issue related to the sustainable development of outer space is the selection of optimal parameters of solar panels for the uninterrupted supply of energy in the power plants of spacecraft. It has been determined that advancing energy-efficient technologies is a prerequisite for ensuring stable space activities. The decision-making process regarding the choice of alternative options for ensuring the electrothermal protection of solar panels in the power plants of spacecraft occurs under the conditions of uncertainty and various risks. A methodical approach to assessing the effectiveness of options for building electrothermal protection systems for solar panels in the power plants of spacecraft has been devised. The hierarchical structure of the problem about approving of the choice of electrothermal protection of solar panels has been constructed on the basis of the method of analytical hierarchical process, which makes it possible to derive a set of optimal options. Five alternative options for electrothermal protection of solar panels have been chosen, which, unlike existing ones, take into consideration the phases of the life cycle, namely, the period of active operation. The selection of criteria for choosing the parameters of electrothermal protection of solar panels in the power installations of spacecraft has been substantiated: ensuring the smooth operation of solar panels; availability of service in emergencies; the life cycle of solar panels; the cost of solar panels; technical safety; mass-size indicators. It is argued that the chosen optimal alternative "Solar panels with protection on the basis of self-resetting fuses" could prolong the active life cycle and, as a result, reduce the number of repairs (current and overhaul) of solar panels in space activities. Owing to the use of this option, positive results could be achieved such an increase in the active life cycle by 20 %, as well as an increase in technical safety by 24 %

The design, test and application on the satellite separation system of space power supply based on graphene supercapacitors

Supercapacitors, also known as ultracapacitors or Electric Double-Layer Capacitors, are considered as new solutions for space power supplies because of their advantages such as a high power-density, a wide temperature range and a long life. Graphene supercapacitors (GSCs), with graphene structure served as the highly active material, are new types of high-performance and new-concept supercapacitors. However, there are no cases of supercapacitors, especially GSCs, being used as power system for spacecraft independently. This paper introduces the design, test and application of the power supply based on GSCs for the electromagnetic separation system in Q-SAT mission. The power supply is integrated by multiple GSCs to meet the requirements of the separation system, providing 600W power within 2 × 10−5 m3 and 1 kg. The design, packaging method, test and result is reported in the paper. The rated voltage of the selected GSCs is 2.7 V, and the power density reaches 1.1 × 103 W/kg and 2.6 × 106 W/m3. The power supply based on GSCs has passed the verification test successfully including mechanical, electrical, vacuum and thermal tests from −20–60 °C. It successfully drove the separation system and guaranteed the task of unlocking and releasing Q-SAT in the flight on Aug 6, 2020. The significance of this work lies in the following aspects: First, the feasibility of application on the satellite separation system in space of GSC is demonstrated. Second, the design and application case of supercapacitor as a driving power supply for a satellite separation system is presented. Third, a screening and integration method for GSCs packaged as a space power supply is proposed and verified. The space power supply based on GSCs will be used more widely in space according to this research.

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.

Modeling and Simulation of Spacecraft Power System Based on Modelica

Spacecraft power system simulation involves the coupling of electrical, thermal and control domains. At present, the modeling and simulation of multi-domain physical system mainly uses the single-domain software to establish a single-domain model, and solves the unified multi-domain modeling and simulation through the interface between the software or using HLA. But it cannot fully support the modeling and simulation of multi-domain physical system, and the model has poor reusability and extensibility. As a multi-domain modeling language, Modelica language supports acausal modelling, unified multi-domain modeling, object-oriented physical modeling and hybrid modeling. So it is widely used in the aerospace area. In this paper, Modelica language is used to establish module library of spacecraft power system on simulation platform MWorks, and the multi-domain simulation model of spacecraft power system is obtained by assembling each sub-model, and the performance of the model is simulated and analyzed so as to achieve the purpose of improving and verifying the model.

Методика оптимизации энергомассовых характеристик системы электропитания геостационарного космического аппарата

This article determines a methodology to maximize a specific power of the electrical power system of a geostationary spacecraft, using the EPS simulation model. A typical (for GEO spacecraft) fully-regulated EPS structure is considered. The advantages of using the full bridge quasi-resonant converters with galvanic isolation are considered. The results of the energy efficiency estimation of power converters at various ranges of input voltages, as well as the criteria and conditions for calculating the positive energy budget of a GEO spacecraft are presented. The application of the EPS simulation model is shown and the results of optimization of the proposed EPS energy and mass characteristics for 6 and 13 kW payloads are described

From Behavioural to In-Depth Modelling of a Scalable Spacecraft Power System in SystemC-AMS using Continuous Integration Techniques

In this work we demonstrate how SystemC-AMS can accompany widely used modelling tools and languages in spacecraft system design. The language bridges a wide range of abstraction levels from a high behavioural description down to the detailed design. To showcase its abilities models of a scalable spacecraft power system are presented. These incorporate distributed analog control loops, digital communication, power electronics, a complex environment and embedded software using the different modelling regimes provided by SystemC-AMS. We show how these models can be used throughout the whole spacecraft system design cycle. The use of abstract models for initial sizing of the power system and high fidelity models for the detailed design of subsystem components is shown. We illustrate how our PCDU Modular Breadboard approach bridges the gap between simulation model and hardware, by making use of the Platform based Design Methodology. In the end we provide an overview of how SystemC-AMS can be embedded into a setup using distributed model execution, configuration control and continuous integration techniques that are focused on software engineering.

Processor-in-the-Loop Simulation of Three Port DC/DC Converter for DC Power Generation and Distribution System

Offline microgrid systems often use DC power generation and distribution systems. The spacecraft power system is a typical application of this system. The demand for massive, intensive launch and diversified functions in new aerospace applications puts forward requirements for off-the-shelf sales, fault tolerance, and rapid integration for the spacecraft power system. This article uses a three-port converter SRB3C to design a scalable DC power generation and distribution system with MPPT and flexible parallel ability. The power converter uses TMS320F28335 as a microcontroller to realize MPPT, droop control, current and voltage closed-loop control, and other functions. To fully verify the system and ensure the reliability of the spacecraft, the processor-in-the-Loop simulation model of the system is built to verify the binary program running in the processor under various operating conditions. The results show that the DC power generation and distribution system composed of SRB3C can meet the needs of spacecraft applications.

System Level Modelling of Batteries in Spacecraft Power System in Multiple Source and Multiple Load Configuration

AbstractIn present day spacecraft applications, power system uses solar arrays as the primary source of power generation and rechargeable Lithium ion batteries as secondary source of power. In normal orbits, during sunlit period, solar arrays support the power requirement from all the subsystems and payloads along with the charge power requirement of batteries. During eclipse period, entire load should be supported by batteries. In addition to the eclipse support, starting from launch pad to till deployment of solar panels, all loads will be on batteries. Contingency loads should also be taken care by batteries. So, battery sizing is very critical part in designing the power system of spacecraft. In multiple source and multiple load configuration where two or more batteries are connected to same Spacecraft power bus, current sharing between the batteries is expected, which needs to be considered for optimized sizing and designing of batteries. The scenario becomes complex with additional constraints namely some loads can come on one battery and not on others or vice versa. Even in a configuration where potential difference exists between batteries, current sharing will start as soon as this difference vanishes. A system level simulation model is developed, using network equations, to analyze in‐circuit performance of batteries in multiple source and multiple load power system. The simulation model uses actual current sharing and predicts State of Charge (SOC) of each battery from which Open Circuit Voltage (OCV) is derived. This OCV of batteries is used periodically for finding actual current sharing which runs in a loop for analyzing battery performance in multisource system. Currently a configuration in which two batteries are connected to two buses, which are paralleled and having different loads, is simulated. Optimized battery sizing, actual current sharing and SOC of each battery are derived. This model can also be extended to a system where more than two batteries are present. Two different approaches are used for simulation and results are compared. The developed generic model has features to use in multiple battery configuration.

Single-Bus and Dual-Bus Architectures of Electrical Power Systems for Small Spacecraft

Nowadays, it has become possible for universities and new businesses to launch satellites of reduced size and cost fulfilling viable missions. Nevertheless, there is still a considerable failure rate that reduces the expected lifetime of these spacecraft. One of the main causes of failure is the power system. Redundancy is one of the main options to enhance its lifetime and lower the failure rate. However, cost, mass, and complexity increase due to redundancy, making it more difficult to complete the projects. Thus, it is necessary to enhance the lifetime of power systems while keeping the development process simple and fast. This paper proposes two configurations of an electrical power system with duplicate components: single-bus configuration has been designed for a nanosatellite not yet launched and dual-bus configuration for a micro deep-space probe launched into a heliocentric orbit. The design and implementation of two dual electrical power systems are described; measurements and on-orbit data of the electrical power system of the micro deep-space probe are also presented, demonstrating that the dual-bus electrical power system can be successfully used in spacecraft. Lastly, conclusions regarding the redundancy considerations for small satellite electrical power systems are drawn based on these two examples.