Competition in the aircraft industry market and global warming has driven the industry to think along economic and environmental lines. This has resulted in the emergence of more electric aircraft (MEA). The increase in the power demand of aircraft, especially in the last two decades, coupled with advancement in battery materials and technology has led to the development of many high energy density batteries. This study presents an overview of the battery systems for MEA. In this paper, a study on the battery technologies used in aircraft in the last five decades is being done. A general background of the battery system is presented and the performance of the batteries based on energy densities and low temperature capabilities are evaluated and discussed. Evolution of MEA with its power system architecture and load profile is presented to understand the requirements of the battery system. Weight saving and cost analysis is done for the Li-ion and Ni–Cd batteries with respect to the requirement of an MEA ‘Aircraft X’. Battery management system (BMS) for Li-ion batteries is also explored and discussed. Based on the analysis, Li-ion battery is selected and integrated with the power distribution DC network for future MEA.

Electric machines have broadly been used in many industries including the transportation industry. With the evolving trend of electrification in transportation, electric machines with higher power density and higher efficiency are demanded and, thus, more stringent thermal management requirements are needed for electrified vehicle applications. This study comprehensively presents various important aspects of thermal management in electric machines with the main focus on transportation applications. Design considerations, challenges, and methods for enhanced thermal management are discussed. Fundamental thermal properties of common materials are presented and sources of losses in various parts of machines are explained. Furthermore, typical cooling techniques and thermal analysis approaches for electric machines are reviewed in detail. This study will serve as a reference guideline for machine designers, who are interested in thermal management, and for thermal researchers working on electric machines.

Range anxiety is an obstacle to the acceptance of electric vehicles (EVs), caused by drivers’ uncertainty regarding their vehicle's state of charge (SoC) and the energy required to reach their destination. Most estimation methods for these variables use simplified models with many assumptions that can result in significant error, particularly if dynamic and environmental conditions are not considered. For example, the combined efficiency of the inverter drive and electric motor varies throughout the route and is not constant as assumed in most range estimation methods. This study proposes an improved method for SoC and range estimation by taking into account location-dependent environmental conditions and time-varying drive system losses. To validate the method, an EV was driven along a selected route and the measured EV battery SoC at the destination was compared with that predicted by the algorithm. The results demonstrated excellent accuracy in the SoC and range estimation, which should help alleviate range anxiety.

Multi-source energy storage systems (MESSs) have been gaining prominence in electric vehicles (EVs) research area. Energy- and power-flow control of on-board MESS and its integration are essential to the performance of urban EVs. Development of an energy management system (EMS) is an important issue with significant influence on the EV range and capabilities. In this study, an innovative coupled energy management algorithm is presented, applied to a fully decoupled MESS containing batteries and supercapacitors (SCs). The proposed energy management algorithm uses an original online filtering technique coupled to a fuzzy logic controller (FLC). The main advantages of the coupled approach and filtering are identified and discussed. The online filtering technique is placed inside the control loop, allowing the decoupling of the frequency of the battery power reference signal given by the FLC. The control loop as well as the EMS were previously simulated in MATLAB/Simulink™ for an urban EV. Furthermore, the coupled EMS has been validated through power-level reduced-scale hardware-in-the-loop (HIL) simulations. The experimental results show the effectiveness of the proposed coupled energy management algorithm. As a result of this development, the proposed EMS is effective in controlling the power-flows with battery lifetime improvement and optimisation in EV performance.

In this study, small-scale solar plants (SPs) coupled with smart public transport system and its coordination with the grid have been presented. Electric buses (EBs) are used for mass transportation and charged from the energy points provided through the ring road of the Guwahati city, Assam, India. Both, the energy storage device and the small-scale SP are connected to each energy point. The maximum priority is given to use solar energy while reducing the energy consumption from the grid to support the EBs. Each energy point consists of a fuzzy logic controller to perform the control actions. The simulations have been carried out to show the system response for all the seasons of a year.

The ride quality and travel comfort of the passenger is based on the type of the suspension system used in the vehicle. The active suspension system is one of the good choices to reduce the vibration and enhance the travel comfort. In this study, a quarter car with integrated seat suspension and driver model (QCSD) is considered for analysis. The controllers are designed for both single actuator (SA) and dual actuator (DA). To reduce the vibration and increase the travel comfort, different types of sliding mode controllers (SMCs) such as fuzzy SMC (FSMC), fractional order SMC and fractional order FSMC (FrFSMC) are designed and simulated in the active suspension system of the QCSD. Three types of road disturbances are used to stimulate the vibration in the system. The responses of the controllers with the QCSD are compared with the passive system and existing state feedback controller. The result shows that the FrFSMC performs better than the other controllers for DA as well as SA. While comparing the DA and SA, DA performs better than SA.

Lithium-ion batteries require an effective battery management system (BMS) to avoid overcharged or overdischarged states resulted from cell imbalance. Nevertheless, most existing BMS methods reduce effective ranges of the battery and might acerbate cell imbalance problem. This study manages cell imbalance problem in both charging and discharging stages based on the same globally active balance module. A two-staged charging and balancing scheme compensates cell inconsistency in the charging stage and evenly charges each cell to full state without overcharging any cell. While discharging, a selective balance method is achieved through an external power source injecting balance current to weakest cell in the series. Balance measures in both charging and discharging stages adopted by the current study aim at extending ranges for the vehicles. The proposed globally active balance module is integrated with a 48 V module BMS and range extension effects are evaluated by experiments with laboratory instruments and field tests on a 96 V prototype electrical vehicle. Test results show the proposed balance method is capable of increasing battery range.

Modelling dynamic behaviours of the lithium-ion (Li-ion) battery and supercapacitor in electric vehicle applications is a key aspect for the emulation of the hybrid power supply. In this study, a dynamical model based on two non-linear equivalent circuits is developed to describe the characteristics of the battery and supercapacitor during both steady-state and transient conditions. The necessary parameters for the proposed model are extracted from measurement data in time and frequency domain using an optimisation algorithm. The developed model is coupled to power electronics devices fed by DC power supply to carry out a laboratory emulator of the hybrid power supply. This tool is mainly used for testing and verification of the electric vehicle performances with convenient and reproducible way. The proposed emulator avoids time-consuming preconditioning and safety problems generally caused by the misuse of electrochemical components such as the Li-ion battery. The modelling and experimental results show a good performance of the hybrid power supply emulator and confirm their feasibility over a wide range of operating points.

Driven by anticipated fuel-burn and efficiency benefits, the more-electric aircraft (MEA) concept is a technological shift in the aviation industry, which seeks to replace mechanical, hydraulic and pneumatic functions with electrical equivalents. This shift has greatly increased the electrical power demands of aircraft and has made MEA networks larger and more complex. Consequently, new and more efficient electrical architectures are required, with interconnected generation potentially being one design approach that could bring improved performance and fuel savings. This study discusses the current state of interconnected generation in the aviation industry and key technological advances that could facilitate feasible interconnection options. This study demonstrates that interconnected systems can breach certification rules under fault conditions. Through modelling and simulation, it investigates the airworthiness-requirements compliance of potential impedance solutions to this issue and quantifies the potential impact on system weight. It concludes by identifying fast fault clearing protection as being a key enabling technology that facilitates the use of light-weight and standards-compliant architectures.