This presentation situates electrochemical accumulators compared to other chemical energy storage. The performances of the different available technologies are presented and a focus is done on Lithium ion accumulator performances and management. The evolutions of some large scale applications and of the level of cost for these markets are detailed.
The world market of e-scooter is expected to experiment an increase of 15% in Western Europe between 2015 and 2025. In order to push this growth it is needed to develop new low-cost more efficient and reliable drives with high torque to weight ratio. In this paper a new axial-flux switched reluctance motor is proposed in order to accomplish this goal. The motor is constituted by a stator sandwiched by two rotors in which the ferromagnetic parts are made of soft magnetic composites. It has a new disposition of the stator and the rotor poles and shorter flux paths Simulations have demonstrated that the proposed axial-flux switched reluctance motor drive is able to meet the requirements of an e-scooter.
The work is focused on modeling and simulation of a supply vessel from a static and dynamic perspective. The aim of the work is to highlight the necessity to implement zonal protection scheme to respect DP3 (Dynamic Position 3) constrains in case of severe busbar faults, operating the system with the tie breaker closed. The model developed is characterized with a complete representation of a ship for Platform Supply - Vessel (PSV). The model represents also the full protection system (static and dynamic) in accordance to the fine tuning conducted on the real system. The work is also focused on the representation of electromechanical model the propulsion power converters. The main objective and the innovation of the work is to demonstrate the ability to sustain severe busbar faults, respecting the DP3 requirement using zonal protection, using a full dynamic model of all the ship electrical system.
This paper presents a design methodology for high power density converter (HPDC) operating as an AC aircraft bus provider, which presents a particular gravimetric power density challenge. High power rating 3-phase AC-DC converter design with weight minimization is elaborated. By considering sizing of major converter parts that contribute to total converter weight, optimal switching frequency to yield highest power density is evaluated. The design evaluation for 50 kW converter with SiC power modules yields overall gravimetric power density of 3.76-5.35 kW/kg at optimal switching frequency of 60 kHz and volumetric power density of 7.04-7.38 kW/l respectively.
JR West has been promoting the energy-saving operation to improve the railway energy efficiency. In this paper, we report the practical energy-saving operation method obtained through the study of energy-saving operation of JR West and the result of its practical use in commercial operation.
The will to reduce carbon dioxide emissions, the desire for independence from fossil fuels and increasing renewable sources of electrical energy has driven the development of electrified propulsion systems for vehicles in recent years. Despite a significant increase in driving range with the introduction of lithium ion technology, the storage of electrical energy in the vehicle still is the biggest challenge. This paper provides an overview of state of the art battery and range extension technology. Furthermore, it shows the key issues in range extender development. Finally, a fuel cell range extender working with hydrogen is introduced which is under development in the public funded project “BREEZE!” with partners from industry and research institutions.
Authors have developed a train running energy simulator with some functions of speed profile generators and an equivalent feeding circuit model for the purpose of the energy estimation of commercial train running. Energy consumption depends on feeding voltage, which varies according to the running position of the train and the condition of other running trains. Therefore, the developed simulator has an equivalent feeding circuit model for commercial train running. This paper verifies the developed simulator using recorded running data of commercial trains.
This paper presents a new approach to design parallelized power inverters used in More Electrical Aircraft equipment. Dimension-based analytical modelling of building components are described and their use to achieve the optimized design is presented. The results help choosing, among various solutions, which is the optimal (minimizing the global mass) parallelization strategy of two power inverters.
In future all-electric ships, which rely on a Medium Voltage DC distribution network, the power system stability can be jeopardized by the presence of constant power loads, due to their negative incremental resistance. In fact, this causes stability problems due to the negative impedance characteristic of tightly regulated converters. The Linearizing State Feedback (LSF) has shown the capability to stabilize these systems. The key modelling assumption for this control is the possibility to neglect cable parameters. In this paper we implement the LSF control in an FPGA hardware and simulate the shipboard power system in RTDS to test the validity of the cable assumption in Hardware in the Loop (HiL) tests.
The Chiyoda line train of Tokyo Metro had the problem of insufficient acceleration while running in rainy condition. We investigated the problem of conventional wheel slip control method and found the solution. We tested the new method in the mainline test with actual train and concluded that the new method works well with better torque performance. In this paper, we report the proposed new control method and the test result.
This paper has details the theoretical background, development and application of a newly developed Automated Stability Assessment Tool for More Electric Aircraft Electrical Power Systems. This tool is shown to provide an easy to use and extremely flexible way for system designers to analyze Electrical Power System stability. It is shown how system parameters can be easily varied in order to investigate their impact on Electrical Power System stability. This methodology could therefore save significant time and money, both by accelerating the design process, and by helping design engineers to select the lowest cost components needed to ensure Electrical Power System stability.
DC grids offer highly efficient distribution of electric energy, eliminating components and optimizing the use of cables. Efficient generation, however, is still based on AC generators. Power-electronic devices link generators and grid and customize energy flow to the loads. Efficient distribution with low losses demands high voltage, e.g. in the range of 10 kV for ship-size grids. Such voltages challenge power electronics as well as protective devices: Short-circuit protection with fast auto-reclosing in a context where fuses are not applicable has to be solved. This paper proposes modular multilevel converters (MMC) with full-bride (4QC) modules and demonstrates fault mitigation in controlled MMC operation by measurement results. The associated control separates asset characteristic defining the steady-state and transient behaviour and converter-near control operating in the subtransient and transient regime. The feasibility of the approach is demonstrated by selected measurement results.
Variations in the network architecture and component choices of superconducting DC networks proposed for future aircraft propulsion systems could have a significant impact on their fault response. Understanding these potential variations is key to developing effective protection solutions for these aircraft applications. To this end, this paper presents the results of sensitivity studies conducted using a representative model of a faulted superconducting DC network in which key system parameters are varied. Of the parameters considered, network voltage and the cable dimensions are shown to have the greatest impact on fault current profile whilst the rate of change of fault current is shown to be sensitive to network voltage and cable length. The paper concludes by exploring the implications of these findings on the prospective protection strategy for future aircraft propulsion systems.
Economic sustainability of running Naval Propulsion Plants is a key element to cope with, and maintenance costs represent a large slice of total operational expenses: last decades' approaches, based on a repairing-replacing methodology, are being trespassed by more effective approaches, relying on effective continuous monitoring of assets wear. In this framework, Condition-Based Maintenance (CBM) is becoming key thanks to the enhancing capabilities of monitoring the propulsion equipment by exploiting heterogeneous sensors: this enables diagnosis and prognosis of the propulsion system's components and of their potential future failures. The success of CBM is based on the capability of developing effective predictive models, for which purpose state-of-the-art Machine Learning (ML) methods must be developed. Nevertheless, testing the performance of ML models for CBM purposes is not straightforward, mostly due to the lack of publicly available datasets for benchmarking purposes: thus, we present in this work a new dataset, that will be freely distributed to the community working on ML models for CBM, generated from an accurate simulator of a naval vessel Gas Turbine propulsion plant. The latter is then used for benchmarking the effectiveness of two state-of-the-art ML techniques in the considered maritime domain.
This paper puts forward a new structure of the HTS DC Motor. This structure has no commutator and brush device, especially HTS material applied to the motor armature part, this can improve the overall efficiency of superconducting motor, solve the problem of the AC loss of motor. The 3D FEM software was used to set up a simplified model of the motor, through the simulation analysis, the structure is reasonable Hence this superconducting motor has a larger advantage compared with traditional structure of motor in the weight, volume, efficiency, loss, reliability. This advantage can be well applied in ship electric propulsion for HTS propulsion motor, play its important role in the field of transportation.
This paper presents the thermal analysis of a five-phase Halbach array permanent magnet synchronous machine. The iron loss is calculated using a hybrid analytical finite element method with segmenting the stator into six parts. The proposed method is compared with both conventional method and pure finite element method. The results show that the proposed technique is accurate whereas it is more simple and time efficient than pure finite element analysis. Higher harmonics losses are also taken into account in the presented technique. Joule losses including end winding loss and also permanent magnet eddy current loss are then calculated and used in a 3-D thermal analysis by finite element method. Thermal distribution and hot spots are determined and a water based cooling system is finally designed for the motor in the worst-case scenario to keep the magnet temperature in a safe range.
Multiphase machines are widely used in electric ship propulsion systems, and the fault-tolerant control of multiphase machines is a very popular research topic. This paper proposes a Fuzzy Logic Vector Control (FLVC) strategy for a 15-phase induction machine (15PIM), which is based on the Fuzzy Logic Control (FLC) and Indirect Field-Oriented Control (IFOC). The FLVC is tested on a 15PIM with concentrated stator windings in MATLAB/Simulink, and the simulation results demonstrate that FLVC has excellent fault-tolerant performance under open-phase conditions, as well as a good performance under healthy conditions.
This paper develops a method to analyse robust stability of a generic electrical power system for safe-critical applications over all operating conditions. Standard methods can guaranty stability under nominal conditions but do not take into account any uncertainties of the model. In this work, stability is assessed by using a Structural Singular Value concept that can provide a measure of stability robustness of a Linear Fractional Transformation (LFT)-based linear system with structured parametric uncertainties. In line with this, the first step was to develop a parameter-dependent linear time-invariant state-space model of the system that is valid for all operating conditions. The model was obtained by symbolic linearisation of the system non-linear model and was further extended to include structured parametric uncertainties of the system. The developed approach was successfully applied to determine the critical destabilising torque of a 4 kW permanent magnet motor drive over the defined range of operating conditions. Matlab robust stability toolbox was used for this analysis. The results were validated against simulation and experimental data.
Silicon (Si) IGBTs are widely used in railway traction converters. In the near future, Silicon Carbide (SiC) technology will push the limits of switching devices in three directions: higher blocking voltage, higher operating temperature and higher switching speed. The first SiC MOSFET modules are available on the market and look promising. Although they are still limited in breakdown voltage, these wideband-gap components should improve traction-chain efficiency. Particularly, a significant reduction in the switching losses is expected which should lead to improvements in power-weight ratios. Nevertheless, because of the high switching speed and the high current levels required by traction applications, the implementation of these new modules is critical. In this paper, the authors focus on the parallel connection of Dual-SiC MOSFET modules. The key points are underlined and an original approach is proposed to design the bus-bar and the gate drive circuit. Experimental results performed on an Opposition Method test-bench, valid the good operation of three Dual-SiC MOSFET modules in parallel.
In the following investigation the modeling of the complete electromechanical system of a doubly fed induction machine is discussed for power production/electric propulsion purposes, when being incorporated as a shaft generator into a ship's system. When the doubly fed induction machine serves as a power production machine, contributes to lower emission of CO2 and fuel saving since its capable of working at different speed (lower) than synchronous. This coincide with the enforcement with which the International Maritime Organization (IMO) and the EU demand reduction of Ship's emissions. The final goal within the frame of this paper is the development of a reliable mathematical model for the mechanical system which includes rotor dynamics and dynamics of tilting-pad journal bearings. The rotor dynamics are expressed in terms of complex variables for the planar coordinates. The total approach aspires to the development of a well established basis for studying the interactions between the electrical and mechanical subsystems and capable of expanding with more complicated models suitable for a reliable design or analysis of various types of faults.
