Energy storage systems (ESSs) are enabling technologies for well-established and new applications such as power peak shaving, electric vehicles, integration of renewable energies, etc. This paper presents a review of ESSs for transport and grid applications, covering several aspects as the storage technology, the main applications, and the power converters used to operate some of the energy storage technologies. Special attention is given to the different applications, providing a deep description of the system and addressing the most suitable storage technology. The main objective of this paper is to introduce the subject and to give an updated reference to nonspecialist, academic, and engineers in the field of power electronics.

Energy Storage Systems for Transport and Grid Applications

Overview of energy storage in renewable energy systems

The implementations of fuel cells (FCs) in the vehicle industry have gained great attention for the last few decades owing to simple utilization, silent operation, high efficiency and modular structure. Technological advancements show that the use of FCs in electric vehicles (EVs) will increase rapidly and cause a revolution, and will be an alternative to traditional vehicles in the future. Commercial vehicles, projects and research show that work is underway to ensure that FCEVs have sufficient performance advances for their daily transportation needs. However, the lack of a detailed study that will shed light on researchers working in this field is obvious. It aims to provide a comprehensive scientific publication on the current status and future expectations to engineers and researchers interested in this field. In the current study, numerous studies have been examined in detail and added as supplementary to the bibliography. In this context, FCEVs are classified under headings of configurations, systems components, control/management, technical challenges, marketing and future aspects. First of all, FC types and electric motors are discussed in terms of their application areas, characteristic properties and operating conditions. Power converters, which are voltage regulation and motor drive topologies used in FCEVs, are detailed according to the structural frequency of use, structure, and complexity. In the next sections, control issues for converters and technical challenges are branched for FCEVs. In final section, the current status and future aspects are reported using a large number of marketing and target data.

A review and research on fuel cell electric vehicles: Topologies, power electronic converters, energy management methods, technical challenges, marketing and future aspects

In flywheel based energy storage systems (FESSs), a flywheel stores mechanical energy that interchanges in form of electrical energy by means of an electrical machine with a bidirectional power converter. FESSs are suitable whenever numerous charge and discharge cycles (hundred of thousands) are needed with medium to high power (kW to MW) during short-time periods (seconds–minutes). Monitoring of the FESS state of charge is simple and reliable as only the spinning speed is needed. The materials for the flywheel, the type of electrical machine, the type of bearings and the confinement atmosphere which all together determine the FESSs energy efficiency (>85%) are reviewed. Main FESS applications: power quality, traction and aerospace are presented. Additionally in this paper it is presented the simulation of an isolated wind power system (IWPS) consisting of a wind turbine generator (WTG), a consumer load, a synchronous machine (SM) and a FESS. A low-speed iron flywheel driven by an asynchronous machine (ASM) is sized for the presented IWPS. The simulation results with graphs for system frequency, system voltage, active powers of the different elements, and FESS-ASM speed, direct and quadrature currents are presented showing that the FESS effectively smoothes the wind power and consumer load variations.

Flywheel energy storage systems: Review and simulation for an isolated wind power system

This paper presents a technical overview for low-noise switched reluctance motor (SRM) drives in electric vehicle (EV) applications. With ever-increasing concerns over environmental and cost issues associated with permanent magnet machines, there is a technical trend to utilize SRMs in some mass production markets. The SRM is gaining much interest for EVs due to its rare-earth-free characteristic and excellent performance. In spite of many advantages compared with conventional adjustable-speed drives, SRMs suffer from torque ripple and radial distortion (and thus noise and vibration) by their nature. Therefore, for high-performance vehicle applications, it is important and urgent to optimize the SRM system to overcome the drawbacks of the noise and vibration. In order to present clear solutions to the acoustic noise in SRMs, this paper starts by analyzing the mechanism of the radial vibration and torque ripples inherent in the motors, and then focuses on the state-of-the-art technologies to mitigate the radial force and torque ripples. It highlights two categories for low-noise SRMs, including the machine topology improvement and control strategy design for radial vibration mitigation and torque ripple reduction. Advanced technologies are reviewed, classified, and compared accordingly. In addition to these methodologies, the schemes that have been developed by authors are also presented and discussed. Finally, the research status on this topic is summarized and forecast research hotspots are presented. It is our intention that this paper provides the guidance on performance improvements for low-noise SRM drives in EV applications.

A Review on Machine Topologies and Control Techniques for Low-Noise Switched Reluctance Motors in Electric Vehicle Applications

In this paper, the design optimization of a nonsalient high-speed permanent magnet synchronous machine (PMSM) for electric vehicle applications is presented. It will be shown how, with a new approach, it is possible to find a deterministic solution to solve the sizing of the machine from a given driving cycle. The optimal geometry and the optimal control strategy over the cycle minimizing both the energy losses and the volume of the machine will be calculated. At first, the one-dimensional analytical model used is presented and validated for the most significant point of the driving cycle using a finite element method. Then, the design methodology and the results through a specific application are detailed. Particularly, it will be shown how the flux weakening, directly given by the design process via the optimization of the control strategy, allows reducing both the energy losses and the constraints on the power converter. At last, in order to validate the solution considering the whole cycle while keeping a reduced computation time, a reluctance network model of the PMSM is used. This model validate the energy losses and the flux densities in the steel parts over the cycle. The study will be done considering the urban dynamometer driving schedule.

Design Optimization with Flux Weakening of High-Speed PMSM for Electrical Vehicle Considering the Driving Cycle

In this paper, a design methodology for surface permanent magnet (PM) synchronous machines, with special application to the case of high-speed machines, will be presented. Following a discussion of the principle and assumptions inherent in the methodology, the analytical model used in the study will be presented. This model will then be implemented to solve the problem of maximizing the power-to-volume ratio from an analytical perspective. It will be shown how this formulation serves to establish design rules, in addition to setting criteria values for the selection of magnetic materials (i.e., silicon steel sheet versus a soft magnetic material). At last, the paper will present a data test bench made of two PM machines designed since the methodology presented herein.

Design Methodology for High-Speed Permanent Magnet Synchronous Machines

In this paper, we investigate the eddy current losses in permanent magnets of surface mounted magnet synchronous machines. An original analytical method based on the magnetodynamic problem of a conductive ring is introduced and the obtained results are compared with the ones given by 3-D FEM analysis. The analytical model considers the effect of the width on the magnet loss. The axial effect is considered through a correction coefficient. The comparison includes the induced current density, the instantaneous losses, the impact of the circumferential segmentation, and the effect of the frequency on the magnet losses. By focusing on the importance of the skin effect and the magnetic reaction due to the magnet currents, the analytical model provides an accurate determination of the magnet eddy current losses.

Improved Analytical Determination of Eddy Current Losses in Surface Mounted Permanent Magnets of Synchronous Machine

In this paper, a novel methodology is presented in order to design a permanent magnet synchronous machine associated with a gearbox for a screwdriver application. The study shows how, from specification such as maximum volume, maximum heating, torque, and speed profiles, it is possible to formulate the sizing problem. The modeling is based on a purely analytical formulation. We will show that it is possible to establish rules in order to make optimal choices of materials (magnets and stator core). The optimization of the pole pair number and the choice of the gear ratio will also be discussed. Finally, the finite element method will be used to validate the designed machine.

Design Methodology of a Permanent Magnet Synchronous Machine for a Screwdriver Application

This paper develops a novel method for optimal design of fractional slot with concentrated windings. The basis of this method is a generalized analytical model of the winding magnetomotive force (MMF) combined with a multiobjective genetic algorithm, which searches the optimal winding parameters that maximize the winding factor and minimize the MMF harmonic content. This technique is applied to optimize the winding layout of the permanent magnet synchronous machine with 12 ×  n slots/10 ×  n poles combination ( n is an integer number). The electromagnetic performances of the optimized winding are investigated and compared with conventional winding topology. It is found that the proposed approach allows the emergence of new windings with higher performances.

Nicolas Bernard

Papers

Design Optimization with Flux Weakening of High-Speed PMSM for Electrical Vehicle Considering the Driving Cycle

Design Methodology for High-Speed Permanent Magnet Synchronous Machines

Improved Analytical Determination of Eddy Current Losses in Surface Mounted Permanent Magnets of Synchronous Machine

Design Methodology of a Permanent Magnet Synchronous Machine for a Screwdriver Application

A Novel Methodology for Optimal Design of Fractional Slot With Concentrated Windings