The logic and the schedule for a rule-based optimization technique useful for energy management onboard the Space Station are presented. A diverse array of experiments is scheduled within the constraints of limited solar energy and battery storage availability, taking into account the uneven energy supply between the sunshine and eclipse periods and the occasional need to serve a peak load and the full battery charging load simultaneously. In addition, the noninterruptible and nonrestartable nature of many experiments has to be accounted for in the schedule. These factors 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 circumstances fewer scheduling tasks are needed and how a closer match between the supply and demand can be obtained. The optimal supply/demand is expressed in terms of the excess and shortage of electricity, the peak load, and the time displacement of the individual payloads. This technique is implemented using Prolog and Fortran. >

Energy management onboard the Space Station-a rule-based approach

Energy Management On board the Space Station-A Ru le-Based Approach

The present invention relates to a system (1) Automatic management of the production and consumption of electricity, in which a site (2) comprises equipment (5) for power generation and aircraft, characterized by the fact that includes sensors (8) for measuring the amount of electricity generated by each device (6); actuators (9) for measuring the amount of electricity consumed and means of control that intelligently manage said autonomy and said reloading of each device (6) by applying a virtual gauge which incrementing and decrementing its value is proportional a relationship between autonomy and loading time.

Automatic management system of production and consumption of electricity.

Sudden surge in power demand or reduction in power supply aboard a vehicle typically require the removal of the less critical loads to maintain the operation of the more critical ones. Conventional approaches assign a priority value to each load and distribute power to the loads in the order of priority, with each load receiving its nominal rated power. As a result, many lower priority loads may be unserviced. However, a large class of loads can operate within a range of input power below the nominal value, albeit with reduced performance. For this class of loads, the degradation in functionality with decreasing input power a continuous, not discrete. The optimal power distribution is conceivably one in which these loads receive only partial power, with a resultant increase in the number of loads serviced and an increase in the overall vehicle functionality. We have developed a method that automates the distribution of partial power to maximize overall vehicle functionality. In addition to the use of priority values, we use fuzzy sets to represent the relationships between the fully functional state of a load and its input power. Using this description, power is iteratively distributed to the loads using fuzzy logic decision rules, taking into account the priority of each load and its power requirement relative to the remaining loads in the set. This algorithm represents an initial alternative to the conventional all-or-none power distribution method. The algorithm is also efficient and practical for real-time power redistribution during contingencies.

http://ieeexplore.ieee.org/iel4/5796/15467/00716914.pdf

Kngwledge-Based Qualitative Modelling and Adaptive Distribution of Power

La presente invention concerne un systeme (1) automatique de gestion de la production et de la consommation d'electricite, dans lequel un site (2) comprend des equipements (5) de production electrique et des appareils, caracterise par le fait qu'il comprend des capteurs (8) de mesure de la quantite d'electricite produite par chaque equipement (6); des actionneurs (9) de mesure de la quantite d'electricite consommee et des moyens de controlent qui gerent intelligemment ladite autonomie et ledit rechargement de chaque appareil (6) en appliquant une jauge virtuelle dont l'incrementation et la decrementation de sa valeur est proportionnelle a un rapport entre son autonomie et son temps de chargement.

Systeme automatique de gestion de la production et de la consommation d'electricite.

During about one third of the Space Station's orbit the solar array output is zero and the payload is served by storage devices It has been found that when a 24-hr cycle is used, some loads onboard the station cannot be scheduled during the desired times It therefore becomes necessary to reduce the cycle length and dispatch period so that a greater number of loads can be served without increasing the size of the power source An approach to optimize the supply and usage of electricity over a shorter time frame is discussed Supply/demand windows of various lengths are implemented for the typical load profile As a result fewer rescheduling tasks are needed and a closer match between the supply and demand is obtained The optimal supply/demand can be refined in terms of the excess and shortage of electricity This technique is implemented using PROLOG and FORTRAN >

S. Rahman

Papers

A knowledge-based approach to optimize the supply and usage of electricity onboard the Space Station