Power Subsystem Research Articles

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.

Reliability, maintainability, and availability methodology based on statistical approach for cooling systems design modification and maintenance

ABSTRACT This study presents a described methodology for reliability analysis, maintenance options, and system availability in all its steps and is graphically presented via a flowchart. The methodology was verified on an example of a cooling plant in the pharmaceutical industry. All the results are presented in diagram and tabular form. For this purpose, two subsystems were selected, and the respective analysis with the results was presented through all the described steps. The methodology is iterative in essence, which means that the procedure sometimes has to be repeated several times to obtain satisfactory results. It is based on a statistical approach; the calculation of individual parameters regarding functions in each step of the methodology was done by applying the Weibull and lognormal distribution. According to the obtained parameter β from the reliability analysis, both observed subsystems were slightly larger than 1, and showed slow equipment aging in the plant. The maintainability analysis for function M(t) also showed that the components of the power subsystem require a shorter time to replace the faulty or worn-out part rather than with the hydraulic cooling subsystem. The value of the parameter σ is relatively low, which means that a little dispersion exists around the mean value of failure numbers.

Conceptual design of a wide band gap based cryogenically cooled MW-class inverter

The increasing need for higher power density and closer integration of power subsystems consisting of superconducting motors/generators, degaussing coils, energy storage modules, and cables leads one to consider the merits of refrigerating the associated power electronics down to cryogenic temperatures. High temperature superconducting (HTS) components combined with cryogenic power converters resulting in high power density power conversion systems will have a significant effect on several industrial, commercial, transportation, and renewable energy applications. Cryogenic power converters provide promising benefits over their room temperature counterparts in terms of reduced size and weight due to increased power density, improved efficiency, switching speed, and reliability. Integration could result in significant weight and space savings for the overall system. In this paper, a conceptual design study on the wide-bandgap-based (especially SiC and GaN) MW-class power inverter/converter is reported. Based on the total power loss of the designed converter, different cryogenic cooling strategies are proposed. The cooling power requirements, cooler mass, the cooler cost is evaluated based on the operating temperature of MW-class power converter. Finally, a power density comparison for different types of conventional power applications and HTS applications together with MW-class power converters is presented. The future of the cryogenically cooled power electronics system together with superconducting power devices is described for large-scale applications such as for future electric aircraft.

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).

Design and Implementation of IoT-Based SCADA for a Multi Microgrid System

This paper deals with the design and implementation of an internet of things (IoT) based supervisory control and data acquisition (SCADA) system for a multi microgrid system. The individual microgrid in this work is suggested to be consisting of solar photovoltaic (PV) array, battery bank, and diesel generator, in addition to national grid. IoT is used to provide a suitable wireless means to transfer the monitoring and control data between the generation subsystems and the microgrid controller. SCADA architecture that make use of IoT infrastructure enables efficient and reliable power sharing and also give a clear image about the system status and subsystem failure and power shortage. This system gets benefit of various sensors, including current, voltage, power, and temperature sensors, that are used to collect data from of the PV array and battery bank, and also gives clear image about power demand in each microgrid. The microcontroller ESP32 is used as remote terminal unit (RTU) controller in SCADA system in order to get data from sensors as well as to communicate with the master terminal unit (MTU). By using Cayenne remote server IoT platform deploy the message queuing telemetry transport (MQTT) protocol to store, monitor, and manage data from a MTU. The designed system is low-cost and effective system to monitor and control microgrids that contain many distributed generators.

Time-domain continuous power flow calculation of electricity–gas integrated energy system considering the dynamic process of gas network

The power flow calculation is a significant basis for the optimized operation of integrated energy systems. For two-way coupled electricity–gas integrated energy systems, the dynamic characteristics of the slow time scale of the gas subsystem make the steady-state energy flow calculation unable to accurately obtain its real-time operating status. In this paper, for the electricity–gas integrated energy system, propose a time-domain continuous power flow calculation method considering the dynamic process of the gas subsystem, which can obtain continuous change of the state variables. The Taylor series expansion method is applied to the power subsystem, the unified energy path model and matching calculation method is used in the natural gas subsystem. The solution is realized by alternating the input and output variables of the coupling element. At the same time, the input of the power subsystem derivative information and the natural gas subsystems frequency domain information makes this method obtain continuous solutions in the time domain, which can meet the time scale requirements in different scenarios. Finally, a calculation example is carried out, and the results show that compared with traditional discrete method, this method can greatly reduce the calculation time under the condition of ensuring a certain degree of accuracy, which verifies the effectiveness of the proposed method.

Distributionally Robust Joint Chance-Constrained Dispatch for Electricity–Gas–Heat Integrated Energy System Considering Wind Uncertainty

With the increasing penetration of wind power, the uncertainty associated with it brings more challenges to the operation of the integrated energy system (IES), especially the power subsystem. However, the typical strategies to deal with wind power uncertainty have poor performance in balancing economy and robustness. Therefore, this paper proposes a distributionally robust joint chance-constrained dispatch (DR-JCCD) model to coordinate the economy and robustness of the IES with uncertain wind power. The optimization dispatch model is formulated as a two-stage problem to minimize both the day-ahead and the real-time operation costs. Moreover, the ambiguity set is generated using Wasserstein distance, and the joint chance constraints are used to ensure that the safety constraints (e.g., ramping limit and transmission limit) can be satisfied jointly under the worst-case probability distribution of wind power. The model is remodeled as a mixed-integer tractable programming issue, which can be solved efficiently by ready-made solvers using linear decision rules and linearization methods. Case studies on an electricity–gas–heat regional integrated system, which includes a modified IEEE 24-bus system, 20 natural gas-nodes, and 6 heat-node system, are investigated for verification. Numerical simulation results demonstrate that the proposed DR-JCCD approach effectively coordinates the economy and robustness of IES and can offer operators a reasonable energy management scheme with an acceptable risk level.

An Analytical Investigation of Anomaly Detection Methods Based on Sequence to Sequence Model in Satellite Power Subsystem.

The satellite power subsystem is responsible for all power supply in a satellite, and is an important component of it. The system’s performance has a direct impact on the operations of other systems as well as the satellite’s lifespan. Sequence to sequence (seq2seq) learning has recently advanced, gaining even more power in evaluating complicated and large-scale data. The potential of the seq2seq model in detecting anomalies in the satellite power subsystem is investigated in this work. A seq2seq-based scheme is given, with a thorough comparison of different neural-network cell types and levels of data smoothness. Three specific approaches were created to evaluate the seq2seq model performance, taking into account the unsupervised learning mechanism. The findings reveal that a CNN-based seq2seq with attention model under suitable data-smoothing conditions has a better ability to detect anomalies in the satellite power subsystem.

Energy efficiency evaluation of power supply system: A data-driven approach based on shared resources

To relieve the problems of energy shortage and environmental pollution, many countries have implemented a variety of policies to improve the energy efficiency of the power industry. To understand the impacts of such policies on energy efficiency, this paper constructs novel network data envelopment analysis models to recognize the policy-induced structural changes in the power system. Compared with previous studies, the new models project the inefficient points onto a more realistic efficient production frontier, considering how the distribution proportion of shared resources will change when the power system, modeled as a power generation stage and a power sale stage, is led by the latter stage. Our empirical study on China’s power system shows that the province of Guangdong and the eastern region of China perform best, and all power production stages perform better than the corresponding power sale stages. The development of the two power subsystems in the four regions is unbalanced. More than half of the power supply systems choose to allocate more proportion of the shared resources to the sale stage rather than use a more balanced distribution between the two stages.

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.

Life cycle assessment of soluble lead redox flow battery

Energy storage deployment for stationary applications is expected to grow in the next decade, and there is a requirement for storage solutions that minimise materials demand. Soluble lead redox flow battery is a type of flow battery in the early phase of design with the potential for a lower cost than other flow battery solutions. This study presents the first cradle-to-gate life cycle assessment of the soluble lead redox flow battery. The ReCiPe2016 method was used to assess the 18 midpoint impact categories for 1 kWh of energy storage capacity. The assessed environmental impact categories were compared with the most advanced flow battery, the vanadium redox flow battery, and other commercially available stationary batteries; lithium-ion batteries, lead acid batteries, and sodium-ion batteries. The most significant environmental impacts of the soluble lead redox flow battery are associated with power subsystem components; stainless-steel end plates (a key component of the stack frame), and polymethyl methacrylate bipolar and monopolar frames. Despite their non-optimised technology, the environmental impacts of the soluble lead redox flow battery show promising results compared to other stationary storage applications exhibiting one of the lowest depletion of material resources of all compared batteries, including lithium-ion batteries, lead acid batteries, and sodium-ion batteries. This is even more evident at higher energy to power ratios. Increasing the energy storage capacity of the soluble lead redox flow battery, and the optimisation of power subsystem components can further improve the environmental performance of the soluble lead redox flow battery.

Flexible operation strategy of an integrated renewable multi-generation system for electricity, hydrogen, ammonia, and heating

Sustainable development and efficient integration of different resources are imperative for future energy systems. To solve the uneven temporal–spatial distribution of renewables, green hydrogen and ammonia can be used as short- and long-term energy storage mediums, respectively. The synergistic effect of introducing these two media into an integrated renewable multi-generation system was examined in this study. The system provided a constant 10 MW electrical baseload and green ammonia when excess hydrogen was available to satisfy the electricity needs for 24 h. The effects of energy storage capacity and baseload electricity were considered. The performance of the system and strategy was thermodynamically investigated, and its generality and feasibility were dynamically evaluated based on the hourly weather data of 10 cities in China in 2020. The analysis revealed that the maximum overall energy and exergy efficiencies were 50% and 73.1%, respectively. The maximum energy efficiency in each subsystem varied from 33.7% to 73.8%, whereas the maximum exergy efficiency changed from 43.5% to 60.9%. In the baseline condition, the total energy outputs of solar, wind, and backup power subsystems were 33.3, 48.5, and 16.4 GWh, respectively. The hydrogen and ammonia yields were 994.5 and 7,201 t·y−1, respectively. The higher hydrogen and ammonia yields of Shenyang, Shanghai, Kunming, and Harbin demonstrate great potential for the development of this system.

Integration and Modeling of Multi‐Energy Network Based on Energy Hub

The energy conversion units and energy storage equipment connected to the multi‐energy system are becoming diversified, and the uncertain factors brought by distributed wind power and photovoltaic power generation make the system energy flow structure more complex, which brings great difficulties to the modeling and application of traditional energy hub modeling methods. This study deeply analyzes the multi‐energy flow coupling structure and operation mechanism of multi‐energy systems, and carries out the power flow calculation and analysis of multi‐energy systems based on an energy hub, so as to ensure the safe and stable operation of regional energy. Based on the physical characteristics of energy systems such as power systems, thermal systems, and gas systems, this article studies the comprehensive power flow model including the electric‐gas‐thermal multi‐energy coupling network and proposes the power flow decomposition of the energy supply subsystem and its applicable equation based on Newton–Raphson method. The effectiveness of the proposed method under different operation modes is verified by case studies. The calculation results show that under constant load, the energy hub running in fixing thermal by electricity (FEL) and fixing electricity by thermal (FTL) mode has little influence on the voltage of each node in the power sub‐network. Within the constraint range, the natural gas flow obtained from the natural gas subsystem is coupled with the power subsystem to meet the load demand. The influence on the power flow at each node of the heat network is not obvious.

Research of diagnostic models of subsystems of power supply of radioelectronic means

The complex indicator of the reliability of electronic means - the readiness factor - significantly depends on the average recovery time. At the same time, the largest labor costs are spent by repair specialists on finding a faulty element. Diagnostic repair support depends on the models used in the development of defect detection algorithms. The most common use of diagnostic models in the form of a graph of information and energy connections, which consists of three types of structures: sequential connection of elements, converging and diverging. The latter did not receive the necessary research.
 In the article as a result of research of influence of forms of the graph of information and power communications on indicators of quality of diagnostic maintenance of subsystems of power supply of radio electronic means analytical dependences of quantitative estimation of the controlled variables on average recovery time are received for the first time. This allows to improve the quality of diagnostic support of existing and promising samples during their design. Minimization of diagnostic errors makes it possible to verify the feasibility of using diagnostic and metrological support during the current repair of electronic devices by the aggregate method, which reduces the recovery time, especially in the field.
 Depending on the volume of initial data, possible methods for quantifying the probability of the preferred choice of branches of power subsystems of radio electronic means, which also reduces the average recovery time by checking primarily the least reliable and do not require much time to perform checks and troubleshooting.
 The obtained results should be used in improving the diagnostic and metrological support of power supply subsystems of existing electronic devices and its development for promising samples in order to improve the quality of maintenance, regardless of the structure of choice.

A Multirange Vehicle Speed Prediction With Application to Model Predictive Control-Based Integrated Power and Thermal Management of Connected Hybrid Electric Vehicles

AbstractConnectivity and automated driving technologies have opened up new research directions in the energy management of vehicles which exploit look-ahead preview and enhance the situational awareness. Despite this advancement, the vehicle speed preview that can be obtained from vehicle-to-vehicle/infrastructure (V2V/I) communications is often limited to a relatively short time-horizon. The vehicular energy systems, specifically those of the electrified vehicles, consist of multiple interacting power and thermal subsystems that respond over different time-scales. Consequently, their optimal energy management can greatly benefit from long-term speed prediction beyond that available through V2V/I communications. Accurately extending the look-ahead preview, on the other hand, is fundamentally challenging due to the dynamic nature of the traffic environment. To address this challenge, we propose a data-driven multirange vehicle speed prediction strategy for arterial corridors with signalized intersections, providing the vehicle speed preview for three different ranges, i.e., short-, medium-, and long-range. The short-range preview is obtained by V2V/I communications. The medium-range preview is realized using a neural network (NN), while the long-range preview is predicted based on a Bayesian network (BN). The predictions are updated in real-time based on the current state of traffic and incorporated into a multihorizon model predictive control (MH-MPC) for integrated power and thermal management (iPTM) of connected vehicles. The results of design and evaluation of the performance of the proposed data-informed MH-MPC for iPTM of connected hybrid electric vehicles (HEVs) using traffic data for real-world city driving are reported.

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.

Acid/base flow battery environmental and economic performance based on its potential service to renewables support

An innovative technology, called Acid Base Flow Battery (AB-FB), has been developed to overcome the intermittent supply of wind and solar electricity generation. It stores electrical energy using pH and salinity differences in the water and compared with other battery technologies, such as Vanadium Redox Flow Battery (VRFB), the new system is expected to be safer, more sustainable and to become a cost competitive option. To provide a deeper knowledge of the new system potentials, in this research, Life Cycle studies under cradle to grave approach have been carried out to assess the environmental and economic performance of 1 MW/6 MWh AB-FB system. Furthermore, 1 MW/6 MWh VRFB has been considered as the reference case. According to the comparative analysis, the AB-FB system exhibited the best environmental and economic performance, placing the AB-FB system as the most sustainable technology. In terms of environmental impacts related to the three process stages, the AB-FB system operation stage yielded the most relevant environmental burden, mostly attributed to energy losses due to the system efficiency. Manufacturing of the AB-FB system was the second stage with the more significant quote to the total environmental burden. Particularly, impacts were related to the power subsystem components being steel, copper, polyethylene and polyvinylchloride identified as the key materials responsible of this tendency. In contrast, the VRFB manufacturing was the most relevant process stage in terms of environmental implications. The energy subsystem was responsible for this tendency due to the vanadium-based electrolyte production related impacts. This component of the VRFB system was also its main constrains in terms of costs. The VRFB investment cost (339 €/kWh) was almost twice the AB-FB one (184 €/kWh), mostly affected by the VRFB electrolyte cost production.

Perspective on photovoltaic optical power converters

Optical wireless power transmission (OWPT) can be used for applications that cannot access traditional power using metal wires. Photovoltaic power-converting III-V semiconductor devices are the core components required for achieving such remote and galvanically isolated power deployments. The development of high-efficiency power converters has already propelled several sensors and probe applications. This growing applied physics field is leveraging the use of ubiquitous laser diode products, now commonly available at various wavelengths. Novel multijunction designs, based on the vertical epitaxial heterostructure architecture devices, have recently allowed fiber-based and free-space applications to quickly progress to higher electrical powers and to benefit from other laser wavelengths. Here, we discuss the perspectives of such multijunction power converters from the viewpoint of realizing additional OWPT deployments and for enabling more probe, sensor, or electronic subsystem power capabilities. The Perspective hence provides a roadmap for devices achieving not only higher conversion efficiency, but also elaborates on the practical aspects necessary to concurrently push the power converters to higher output powers. The photovoltaic multijunction power-converting device is particularly a game-changer for smartly increasing the output voltage and therefore maintaining practical optimal external loads at high laser input powers. Examples of conversion efficiencies above 60% for output powers up to 17.5 W are demonstrated at ∼808 nm in this study, and up to 22 W of output power is obtained with an efficiency of 48.9% at ∼980 nm.