On-board Power System Research Articles

Onboard power systems based on hot water energy storage for green vehicles as an alternative to battery electric vehicles

This paper introduces the concept of onboard hot-water-storage-based power systems for green vehicles. The hot water at a moderately high temperature is stored onboard vehicles and its thermal energy is used to produce wheelwork through a heat engine to drive vehicles without combustion. The hot water’s wheelwork storage density matches or exceeds that of battery packs of electric vehicles (EVs). When hot water is produced by solar energy, its overall solar utilization efficiency is more than 1.5 times higher than that of battery EVs with a 60% land-use reduction. The design and integration of hot-water storage modules for semi-trucks, delivery vans, and SUVs are demonstrated with detailed technical calculations. The results show that hot-water vehicles (HWV) can outperform EVs in terms of driving ranges. The HWV could be a truly renewable and clean vehicle and a direction to achieve sustainability with positive impacts on the earth and transportation industries.

Analysis and improvement of power quality in the onboard electrical power systems within a self-propelled floating crane

This research addresses electromagnetic compatibility and power quality (EMC and PQ) challenges in shipboard electric power systems (SEPS) with dynamic positioning (DP) capabilities, focusing on the self-propelled floating crane (SPFC) “EXPERT 3.” Our goal is to enhance methodologies for evaluating power quality indicators (PQI) related to voltage and current waveform distortions, specifically in converter-based propulsion complexes (CBPCs) featuring variable-frequency regulated asynchronous drives (VFDs). We investigate harmonic current and voltage distortions, reactive power generation, and power factor (PF) in SEPS “EXPERT 3″ during the operation of VFDs with conventional semiconductor power converters (SPCs). A refined MATLAB model considers equipment and cable network parameters, validating distortion indicators at ship synchronous generators (SGs). PQI compliance with international maritime standards is verified at the point of common coupling (PCC) for various VFD configurations with pulse width modulated (PWM) SPCs and filter-compensating devices (FCDs). We propose an improved controlled FCD (CFCD) incorporating a resonance filter (RF) and a controllable reactor compensator (CRC). CFCD efficiency in various VFD configurations is experimentally validated. We analyze harmonic distortions of voltage and current, including high-frequency (HF) commutations in VFDs with input thyristor-based rectifiers (TBRs), considering parasitic ”phase-hull“ capacitances of cable line segments (CLS). Our study examines harmonics in CBPC-based SEPS in two sub-frequency ranges: low-frequency (LF) − 0 to 2 kHz and high-frequency (HF) − 2 kHz to 500 kHz.© 2017 Elsevier Inc. All rights reserved.

Power Generation Optimization for Next-Generation Cruise Ships with MVDC Architecture: A Dynamic Modeling and Simulation Approach

The cruise industry is obliged by economic and environmental initiatives to pursue fuel-efficient solutions and lower ship exhaust emissions. The medium voltage DC (MVDC) distribution with intelligent power management has become a concept for next-generation onboard power systems as its energy-saving feature is to eliminate the frequency constraint and simultaneously optimize engine loads and speed in response to load variations. The incentive for this transition lies on one hand in the fuel efficiency consideration and the reduction of power losses from serial conversion stages. On the other hand, the DC-based technology has been conceived as high-power density design, thus significantly increasing the payload. This study investigates such potential benefits focusing exclusively on large cruise vessels. A highly representative model of the integrated power platform that incorporates all dynamic interactions from the ship hull and essential machinery typically installed on board cruise ships is proposed. The power management strategy also takes account of actual sea conditions and real-time operation requirements. The simulation results demonstrate that the optimization-based MVDC system is able to maximize the opportunity of search agents in finding optimum fuel efficiency areas throughout the scenario time. An analysis of the system structure weight and space reduction of the MVDC architecture is also performed through the utilization of more compact electrical distribution devices and very high power-dense combustion turbines.

Stochastic Optimization of Onboard Photovoltaic Hybrid Power System Considering Environmental Uncertainties

Environmental uncertainties present a significant challenge in the design of onboard photovoltaic hybrid power systems (PV-HPS), a pivotal decarbonization technology garnering widespread attention in the shipping industry. Neglecting environmental uncertainties associated with photovoltaic (PV) output and hull resistance can lead to suboptimal solutions. To address this issue, this paper proposes a stochastic optimization method for PV-HPS, aiming to minimize greenhouse gas (GHG) emissions and lifecycle costs. Copula functions are employed to establish joint distributions of uncertainties in solar irradiance, ambient temperature, significant wave height, and wave period. Monte Carlo simulation, the bi-bin method, and the multi-objective particle swarm optimization (MOPSO) algorithm are utilized for scenario generation, scenario reduction, and design space exploration. The efficacy of the proposed method is demonstrated through a case study involving an unmanned ship. Additionally, deterministic optimization and two partial stochastic optimizations are conducted to underscore the importance of simultaneously considering environmental uncertainties related to power sources and hull resistance. The results affirm the proposed approach’s capability to reduce GHG emissions and lifecycle costs. A sensitivity analysis of bin number is performed to investigate the tradeoff between optimality and computation time.

Development of on-board power systems and the concept of a more electric aircraft

The article reviews the main stages of development of aircraft power systems. The basic features of the power node for the Mi-24 combat helicopter, a multi-tasking aircraft, are presented F-22 and the Boeing B-787 passenger airplane. The results of the analysis of methods for managing the distribution of electricity on both conventional aircraft and the most modern aircraft structures (A-380, B-787) are presented. The basic structures of the aircraft's on-board power network are presented, divided into three periods: the period until the 1960s (with the dominance of the direct current network with a voltage of 28.5 V), the period until 2000 (with the dominance of the three-phase alternating current network with a voltage of 3 x 115 V / 200 V, 400 Hz) and the most recent period, after 2000 (dominated by a 270 V direct current network, obtained by converting the voltage from a three-phase alternating current generator 3x 115 V / 200 V, 400 Hz using a transformer-rectifier block). The concept of a more electric aircraft was presented as the main direction of current construction works for MEA concept (More Electric Aircraft).

Proposal of a Process for selection solar cells Nanosatellite

By the PEDAGOSAT project we aim to democratize all educational activities related to CubeSat-class: nanosatellite, from physics through engineering, technical achievements, integration, to testing and operations to the greatest number of students. The key idea is to eventually have our academic nanosatellite training platform offering an open source opportunity to Algerians universities, and having the capacity to cover all engineer training areas relating to "small satellites". As part of this project, some satellite subsystems, test and emulation facilities will be realized, processes and procedures for testing and integration related to space technology will be addressed, implemented and even mastered. The presented work is part of the development of the on-board power system, and covers the selection of solar cells for the manufacture of solar panels of this satellite. The main source of energy present in space is solar energy, it a continuous and inexhaustible source that a satellite can. In satellite we use a solar panel to ensure its operation. In the dimensioning of a satellite, it is essential to identify these electrical power requirements named “power budget analysis”. Indeed, this makes it possible to determine the number of cells and/solar panels to be installed to guarantee the power continuity of the satellite in sunlight phase of its orbit by recharging its batteries and feeding equipment’s. During all the mission duration; from the beginning of life (BOL) after the launch to it deorbits (EOL) to disintegrate in the atmosphere. For the PEDAGO-SAT as for other satellites, it will be necessary to verify the parameters and physical characteristics of the solar cells/panels according to certified procedures and methodologies in order to be able to pronounce on their qualification for aerospace use. In this context, we propose a low-cost process revision to be able to carry out qualification tests with an accessible facility in the university labs. This revision will also concern the development of homemade means and software that fit the investments that may be made by the Algerian research and academic facilities. As illustrated in this paper a performance evaluation of low-cost solar cells was done using the developed solution and the selected cells will be integrated in the solar panels of PEDAGOSAT.

The Architecture of the on-Board Power System of a More Electric Aircraft

The Architecture of the on-Board Power System of a More Electric Aircraft

Regenerated Energy Absorption Methods for More Electric Aircraft Starter/Generator System

In more electric aircrafts, more motor loads are applied onboard. When the motor is braking, the regenerated energy need to be absorb to avoid dc-link voltage variations. Two regenerated energy absorption methods are proposed for the generator based on diode rectifiers and the starter/generator (SG) based on active rectifiers respectively. When the regenerated power is lower than other loaded power, both SG and generator systems can absorb it by reducing the output power. When the regenerated power is higher than other loaded power, if the SG is directly connected to the engine shaft, the regenerated energy can be absorbed by changing the SG operation from generating to motoring. The regenerated energy can be returned directly to the dc-link without extra devices and the dc-link voltage is under control during the regenerated energy absorption. The efficiency is improved and the heat is reduced by the proposed regenerated energy absorption methods. The generator and SG systems are implemented and the regenerated energy absorption methods are verified by experiments. The efficiency of the onboard electrical power system is improved.

Reduction of Auto-Power Procedure Influence on the Photovoltaic Inverter On-Board Bus System Caused by Pulsed Loads

The article presents an on-board power system designed for ships, aviation, and space vehicles using energy from photovoltaic panels. The power structure includes both DC and high-frequency AC power buses. As a result of pulse loads, this system is exposed to disturbances that cause electronic systems to reboot. To reduce the effect of the appearance of secondary disturbances in the AC bus to which the photovoltaic converter is connected, a new control strategy has been proposed. This strategy improves the operation of the proportional resonant regulator that controls the AC bus current by making the reference values linearly dependent on the DC bus voltage. A prototype of such a system was designed in the laboratory. The FPGA control board was pulse-disturbed, leading to start the auto-power procedure, and additional disturbances were observed in the AC bus for the standard system. Reduction in the impact of these disturbances was achieved using the proposed control method by reaching a limitation of the bus current in dynamic states caused by the auto-power on process from 280% to less than 100% of the steady-state value. Experimental results verified the validity of the proposed method.

Hybrid PEM Fuel Cell Power Plants Fuelled by Hydrogen for Improving Sustainability in Shipping: State of the Art and Review on Active Projects

The interest in hybrid polymer electrolyte membrane fuel cells (PEMFC) fuelled by hydrogen in shipping has seen an unprecedented growth in the last years, as it could allow zero-emission navigation. However, technical, safety, and regulatory barriers in PEMFC ship design and operation are hampering the use of such systems on a large scale. While several studies analyse these aspects, a comprehensive and up-to-date overview on hydrogen PEMFCs for shipping is missing. Starting from the survey of past/ongoing projects on FCs in shipping, this paper presents an extensive review on maritime hydrogen PEMFCs, outlining the state of the art and future trends for hydrogen storage and bunkering, powertrain, and regulations. In addition to the need for a clear regulatory framework, future studies should investigate the development of an efficient fuel supply chain and bunkering facilities ashore. As for the onboard power system, health-conscious energy management, low-temperature heat recovery, and advancements in fuel processing have emerged as hot research topics.

Unified Power Systems Engineering of Mobile Technical Objects

Currently, the focus on the integration of technical objects is one of the recognized trends in the development of most areas of technical sciences. The ideas of horizontal and vertical integration tested in shipbuilding are considered. In particular, the ideas laid down in the concept of electric propulsion, a unified power systems engineering and an electric ship, which have a high scientific potential and should become a theoretical and practical basis for improving the power systems engineering of various mobile technical objects. Taking into account political realities and market conditions, first of all, it is suggested to use the expressed proposals for creation and improvement of on-board power systems engineering for a line of unmanned uninhabited objects (in the future covering the needs of aircraft, marine underwater and surface vehicles).

Efficiency Focused Energy Management Strategy Based on Optimal Droop Gain Design for More Electric Aircraft

Due to the substantial increase in the number of electrically driven systems onboard more electric aircraft (MEA), the onboard electric power systems (EPSs) are becoming more and more complex. Therefore, there is a need to develop a control strategy to manage the overall EPS energy flow and ensure the operation of safety-critical systems (which are electrical loads) under different operating scenarios and to consider EPS losses minimization, exploiting the thermal capability of generators, different load priorities, and available batteries with their charging and discharging schedules. This article presents an energy management (EM) strategy that considers the aforementioned objectives. The optimal droop gain approach is employed as a power-sharing method to minimize the total EPS losses in MEA. A finite state machine (FSM) has been used to implement the control strategy to realize the EPS reconfiguration operation. The proposed EM strategy is implemented and simulated using MATLAB/Simulink and hardware-in-the-loop (HIL) under different operational scenarios, such as normal operations, failure of one of the power generation channels, and failure of all power generation channels. The proposed EM method has shown its capability to efficiently manage the EPS under different operating conditions to reduce the overall system losses.

A multi‐layer framework for energy efficiency assessment of shore‐to‐ship fast charging systems including onshore batteries

This paper proposes a three-layer framework for energy efficiency evaluation of Shore-to-Ship Charging (S2SC) systems using load-dependent loss models of the components. The considered S2SC system is supplied by the grid but is also supported by On-Shore Batteries (OSB). The presented approach is then used to investigate the impact of the specific design and operational parameters on energy efficiency. Power system architectures for three general S2SC solutions for ac, dc, and inductive charging are defined and compared in terms of energy efficiency. Operational parameters are also considered in the analysis, namely, the grid power ratio, determining the load sharing between the grid and the OSB, as well as the OSB charging profile. A case study is performed with peak charging power of 1 MW, and the most efficient S2SC solutions are identified for both ac- and dc-based onboard power systems. Moreover, it is shown that charging OSB with the highest available power from the grid between the charging breaks would often lead to higher energy efficiency than the maximum utilization of the available charging time. Field data from a real S2SC system is used to verify the estimated energy efficiency by the proposed framework. The analysis of the real case S2SC is then extended to include and verify a projected OSB.

Study on application of large civil aircraft passenger door actuation system based on super capacitor

The development of multi-charge technology has led to more and more types of power sources and electric actuators that can be selected on the civil aircraft. It is a developing trend that full-automatic passenger door actuation system will gradually replace the traditional mechanical and semi-automatic passenger door actuation system in the future. This paper designs a set of full-automatic passenger door actuation system, the movement of the latch and lock mechanism, and the opening mechanism is completely controlled by more electric actuators. In normal work, the on-board power system provides power for the passenger door actuation system, and when the power system fails, it automatically switches to the battery to provide power for the system. When passenger door is opened in an emergency, the actuator for the opening door need continuous high current, the storage battery can not meet the requirement, and it will also have a large impact on the battery's pole plate, reducing the power consumption battery life. This paper studies a new type of passenger door actuation system that uses super capacitor as emergency actuation energy, and determines the combination of on-board power, battery and super capacitor into a composite power system, and proposes a power distribution control strategy, and establishes a simulation model of super capacitor charge and discharge and performing simulations. The simulation results show that the system can meet the time requirements for emergency activation of the passenger door.

Strategy Design and Performance Analysis of an Electromechanical Flywheel Hybrid Scheme for Electric Vehicles

Energy management strategies are one of the key factors affecting the working efficiency of electric vehicle energy power systems. At present, electric vehicles will develop real-time and efficient energy management strategies according to the topology of on-board energy power system to improve the driving performance of vehicles. In this paper, a new electromechanical flywheel hybrid system is studied. Firstly, the characteristics of the topological scheme of the electromechanical flywheel hybrid system are analyzed, and the working modes are designed. Secondly, in order to improve the efficiency of vehicles’ energy utilization and ensure the real-time performance of the management strategy, an energy management strategy based on fuzzy rules is designed with the flywheel’s state of energy (SOE) as the key reference parameter. Then, considering the directional stability in the braking process, the braking force distribution strategy between the front axle and the rear axle is designed. In order to improve the braking energy recovery efficiency, the secondary distribution strategy consisting of a mechanical braking force and regenerative braking force on the front and rear axles is designed. Finally, the bench test of a electromechanical flywheel hybrid system is carried out. Experiments show that compared with the original dual-motor four-wheel drive scheme, the electromechanical flywheel hybrid four-wheel drive system scheme developed in this paper can reduce the current variation range of lithium batteries by 43.16%, increase the average efficiency by 1.04%, and increase the braking energy recovery rate by 40.61% under the Japan urban cycle conditions. In addition, taking advantage of the energy and power regulation advantages of the electromechanical flywheel device, the power consumption of the lithium battery is reduced by 1.82% under cycling conditions.

Model-based efficiency and emissions evaluation of a marine hybrid power system with load profile

In this paper, an efficiency and emissions evaluation framework for marine DC hybrid power systems is developed based on the physics- and data-based models of the power components. The proposed framework is tested under the operational profile of a real-case semi-submersible drill rig with all-electric propulsion and a suggetsed DC hybrid power system with batteries. The applied load profile, including propulsion, drilling, auxiliary, and hotel loads, shows high fluctuations, indicating the need for battery hybridization. In addition to the operational profile, the impact of the onboard power system configuration, sectionalized and common bus, on the emissions and efficiency has been studied. The results include the total energy efficiency of the ship powertrain from fuel to propulsion load and total CO2 emissions. For the considered vessel power system and operational profile, it is observed that the sectionalized bus configuration performs slightly better in terms of energy efficiency, and consequently fuel consumption and CO2 emissions.

A refined model of turboprop regional aircraft on-board electric power system for fault reconstruction simulation

With the rapid development of the aviation industry, more and more regional flights have been put into commercial use to meet the needs of different regions. In order to respond to the call for “carbon neutrality”, regional aircrafts also need to develop towards the trend of “more-electric”. When designing an on-board electric power system, a large number of simulation experiments are required to measure the operation of the entire system in steady state and various fault conditions. Therefore, there is an increasing demand for more accurate modeling of on-board power systems. Especially under fault conditions, it is extremely helpful for the design of the reconstruction diagram to accurately simulate the reconstruction sequence under fault conditions. In this paper, the hardware modeling of the contactor and the hardware interlock structure are modeled, which makes the modeling of the on-board power system more accurate. This paper also builds a classic turboprop regional aircraft power system at the behaviour level, and carries out the simulation under steady state and TRU fault conditions, showing that both the transient process and the reconstruction sequence can be accurately simulated.

Data-Driven Efficiency Modeling and Analysis of All-Electric Ship Powertrain: A Comparison of Power System Architectures

In this article, a data-driven dynamic efficiency model is developed for efficiency evaluation and comparison of ship electric powertrain with various system configurations. Based on the proposed method, the entire powertrain efficiency is assessed from the fuel consumption to the propulsion unit and the rest of the onboard load. The efficiency model is repeated for the conventional diesel electric and the hybrid power system with batteries. In the latter case, the efficiency of the battery system is also included in the model. Then, the analysis is extended for different power system architectures such as AC and DC onboard power systems. As a case study, system efficiency in a cruise ship is investigated using a real operational profile. A comprehensive analysis is performed to demonstrate the loss distribution in each subsystem of a hybrid AC and DC power system. For a fair comparison between AC and DC, the battery charge level is equalized based on fuel compensation. The case study shows that hybridizing the ship power system increases system efficiency and enhances operational flexibility for the studied use case vessel. Furthermore, the DC hybrid power system can improve the efficiency of the whole ship powertrain due to the variable-speed operation of engines.

High-Voltage Shore Connection Systems: Grounding Resistance Selection and Short-Circuit Currents Evaluation

Cold ironing represents an effective solution to remove air polluting emissions from ports. The high voltage shore connection system is the key enabling facility that allows to provide power from the shore side electrical system to the ship. The design of the shore connection needs a comprehensive assessment of the fault currents in different operating scenarios. International standards require the neutral point of the shore connection transformer be equipped with a neutral grounding resistor. Its value has to be defined to guarantee safety and protection of equipment and personnel in case of single phase-to-ground faults. Moreover, three-phase short circuits need to be considered to size equipment and protection devices. A crucial role is played by the frequency converter control system, required to adapt the mains frequency to the frequency of the ship. In this work, a complete electro-magnetic dynamic model of the high voltage shore connection and of the on-board power system has been developed, including frequency converter, shore-side transformer, connection MV cables and power system of the ship, to analyze in detail the behavior of the system in case of single phase-to-ground fault and three-phase short circuit, taking into account relevant standards and best practices.

Multi-level model predictive control for all-electric ships with hybrid power generation

Power availability to preserve propulsion is a vital issue in the shipping industry which relies on persistent power generation and maintaining the stability of the power and propulsion system. Since the introduction of on-board all-electric Direct Current Power and Propulsion Systems (DC-PPS) with hybrid power generation, which are more efficient compared to direct-diesel and Alternating Current (AC) all-electric configurations, there have been extensive investigations on stabilization and power generation control to enable robust and reliable performance of DC-PPS during different ship operations. In this paper, a multi-level approach is proposed for hybrid power generation control. For this goal, first, a mathematical model is proposed for each power system component and then, the overall on-board power system is modeled in a state space format. Then, a multi-level Model Predictive Control (MPC) approach is proposed for the DC voltage control which unlike conventional droop control approaches, takes the DC current generated by power sources into account explicitly. The performance of the proposed approach is evaluated via several simulation experiments with a high fidelity model of a high voltage DC-PPS. The results of this paper lead to enabling more effective approaches for power generation and stability control of constant power loaded microgrids.