Development of A Load Control Algorithm to Enhance Energy Sustainability for the International Space Station (original) (raw)
Related papers
2002
The electrical power system developed for the International Space Station represents the largest spacebased power system ever designed and, consequently, has driven some key technology aspects and operational challenges. The full U.S.-built system consists of a 160-Volt dc primary network, and a more tightly regulated 120-Volt dc secondary network. Additionally, the U.S. system interfaces with the 28-Volt system in the Russian segment. The international nature of the Station has resulted in modular converters, switchgear, outlet panels, and other components being built by different countries, with the associated interface challenges. This paper provides details of the architecture and unique hardware developed for the Space Station, and examines the opportunities it provides for further long-term space power technology development, such as concentrating solar arrays and flywheel energy storage systems. 17. SECURITY CLASSIFICATION OF REPORT Unclassified
Modeling and simulation of Space Station Laboratory Module Electric Power System
Intersociety Energy Conversion Engineering Conference, 1994
This paper describes modeling and simulation of International Space Station Laboratory Module (US LAB) Secondary Electric Power System (SEPS). The US LAB SEPS consists of multiple levels of switching DCIDC converters with negative resistance characteristics. Subsystems that contain these DCIDC converters may interact with each other which may result in poor power quality and in extreme cases system instability. In this paper LAB SEPS is modeled using EASY5x software. Capabilities of EASYSx in modeling and analysis of large power systems are described. The concept of modularized modeling of power systems is described. Examples of modeling DCIDC converters using averaging techniques that are easily implemented in EASY5x are presented. Subsystem interaction and methods of analysis of distributed power systems are discussed. Results of small signal stability analysis of the power system is given.
12th International Energy Conversion Engineering Conference, 2014
The development of distributed hierarchical and agent-based control systems will allow for reliable autonomous energy management and power distribution for on-orbit missions. Power is one of the most critical systems on board a space vehicle, requiring quick response time when a fault or emergency is identified. As NASA's missions with human presence extend beyond low earth orbit, autonomous control of vehicle power systems will be necessary and will need to reliably function for long periods of time. In the design of autonomous electrical power control systems there is a need to dynamically simulate and verify the Electrical Power System (EPS) controller functionality prior to use on-orbit. This paper presents the work at NASA Glenn Research Center in Cleveland, Ohio where the development of a controls laboratory is being completed that will be utilized to demonstrate advanced prototype EPS controllers for space, aeronautical and terrestrial applications. The control laboratory hardware, software and application of an autonomous controller for demonstration with the ISS electrical power system is the subject of this paper.
System performance predictions for Space Station Freedom's electric power system
Space Station Freedom Electric Power System (EPS) capability to effectively deliver power to housekeeping and user loads continues to strongly influence Freedom's design and planned approaches for assembly and operations. The EPS design consists of silicon photovoltaic (PV) arrays, nickel-hydrogen batteries, and direct current power management and distribution hardware and cabling. To properly characterize the inherent EPS design capability, detailed system performance analyses must be performed for early stages as well as for the fully assembled station up to 15 years after beginning of life. Such analyses were repeatedly performed using the FORTRAN code SPACE (Station Power Analysis for Capability Evaluation) developed at the NASA Lewis Research Center over a 10-year period. SPACE combines orbital mechanics routines, station orientation/pointing routines, PV array and battery performance models, and a distribution system load-flow analysis to predict EPS performance. Time-depe...
Energy management onboard the Space Station-a rule-based approach
IEEE Transactions on Aerospace and Electronic Systems, 1991
The logic and the schedule for a rule-based optimization techniqm useful for energy management onboard the space station is presented. The need to schedule a diverse array of experiments, within tbc constraints of limited solar energy and battery storage availability, calls for a delicate energy demand and supply balance. This has to take into account the uneven energy supply between the sunshine and eclipse periods, and occasional need to simultaneously serve a peak load and the full battery charging load. In addition, the noninterruptible and nonrestartable nature of many experiments have to be accounted for in the schedule. These have been accounted for by using various time intervals and priority weighting factors Supply/demand windows of various durations are tested for the typical load profile. This shows under what circunstances kss scheduling tasks are needed and how a closer match between the supply and demand can be obtained The optimal supply/demand is expressed in terns of the excess and Manuscript
Space Station Freedom electrical performance model
The baseline Space Station Freedom electric power system (EPS) employs photovoltaic (PV) arrays and nickel hydrogen (NiH2) batteries to supply power to housekeeping and user electrical loads via a direct current (dc) distribution system. The EPS was originally designed for an operating life of 30 years through orbital replacement of components. As the design and development of the EPS continues, accurate EPS performance predictions are needed to assess design options, operating scenarios, and resource allocations. To meet these needs, NASA Lewis Research Center (LeRC) has, over a 10 year period, developed SPACE (Station Power Analysis for Capability Evaluation), a computer code designed to predict EPS performance. This paper describes SPACE, its functionality, and its capabilities.
2005
Distributed power systems offer many benefits to system designers over central power systems such as reduced weight and size. Distributed systems also allow the designers to control the quality of power at different loads and subsystems, since DC-DC converters allow close regulation of output voltage under wide variations of input voltages and loads. Distributed power systems also provide a high degree of reliability because of the isolation provided by DC/DC converters; it is very easy to isolate system failures and provide redundancy. These systems are also very flexible and easily expanded. This paper addresses the DC distributed power system of the International Space Station, which is a specific case of this kind of distributed system. It is a channelized, load following, DC network of solar arrays, batteries, power converters, switches and cables which route current to all user loads on the station. The completed architecture consists of both the 120-V American and 28-V Russian electrical networks, which are capable of exchanging power through dedicated isolating converters. The presence of DC/DC converters required special attention on the electrical stability of the system and in particular, the individual loads in the system. This was complicated by complex sources and undefined loads with interfaces to both sources and loads being designed in different countries (US, Russia, Japan, Canada, Europe, etc.). These issues, coupled with the program goal of limiting costs, have proven to be a significant challenge to the program.
IECEC 96. Proceedings of the 31st Intersociety Energy Conversion Engineering Conference
As space direct current (dc) power systems continue to grow in size, switching power converters are playing an ever larger role in power conditioning and control. When designing a large dc system using power converters of this type, special attention must be placed on the electrical stability of the system and of the individual loads on the system. In the design of the electric power system (EPS) of the International Space Station (ISS), the National Aero-17. SECURITY CLASSIFICATION OF REPORT Unclassified
Energy Management System allows the customers to control, optimize and monitor their energy consumption, which directly translates to a reduction in energy bills. This paper is aimed at addressing such issues, mostly in public places and some other places of interest. The work demonstrates the interaction between the load points referred to as nodes and a central controller, which implements measuring, monitoring, and controlling the energy consumption of various segments of the network, hence conferring on the system operator the powers to regulate the energy consumption of the network from a central point remotely. This work is achieved by measuring and studying the consumption pattern and pegging a threshold, based on a very robust energy allocation plan. The case study is a network of Engineering Students' Hostel University of Agriculture Makurdi, Benue State, Nigeria, which was modelled using a simple MATLAB code to fit the measured consumption curve, which produce the threshold value. These values were programmed microcontroller, representing the central controller, employed to implement the control of energy consumption at the nodes. The results obtained show that the microcontroller was able to control the power consumption by switching ON, when the consumption was below the threshold value and switching OFF, when it was above. The switching action of the microcontroller enabled energy savings, thus translating to reduced electricity bills
IEEE Transactions on Aerospace and Electronic Systems
CubeSats have been gaining significant interest as a cost-effective solution that can be built with low power requirements for different mission types. The most critical subsystem in CubeSats is the Electrical Power Subsystem (EPS), which provides the required power to operate the remaining subsystems. This paper presents an approach for optimizing load management and scheduling in CubeSat applications to ensure optimal coordination between the load demand, power generation, and energy storage while maintaining communication's quality of service requirements, namely the data rate and Bit-Error-Rate (BER). The loads are divided into four types based on their priority. The load types are time-modulated, magnitudemodulated, time-and-magnitude-modulated, and fixed. An optimization problem is formulated with data rate and BER in the cost function, while maintaining energy and power constraints. Multiple cases are investigated with different mission requirements. The solution obtained shows that the proposed scheduling algorithm meets the communication system's requirements while conserving power and energy resources.