Traditional Electric Vehicles Research Articles

A Rapidly Reconfigurable DC Battery for Increasing Flexibility and Efficiency of Electric Vehicle Drive Trains

Traditional electric vehicle (EV) battery drive trains comprise hard-wired batteries forming a fixed high-voltage DC link, and a main inverter. This paper proposes a novel topology to break hard-wired batteries into smaller subunits interfaced by low-voltage field effect transistors (FET). The new DC link, named <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reconfigurable DC battery</i> , can offload a great portion of the switching duty from the main inverter. Several benefits follow: <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1)</i> The proposed topology reduces the total loss despite the added components. The net loss is reduced because the reconfigurable DC battery can generate an optimal high-frequency voltage waveform to spare up to 2/3 of the switching actions of the main inverter—i.e., delegating the modulation duty from the main inverter to the reconfigurable DC battery. The added semiconductor loss is negligible compared to that of the main inverter, thanks to small voltage steps of multilevel conversion and the latest low-voltage transistors. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2)</i> The main inverter’s output waveform has less distortion, e.g., down to 50% compared to conventional space-vector modulation. This distortion reduction is a consequence of large segments of the overall output voltage (particularly the apex) being entirely formed by the reconfigurable DC battery with multilevel precision. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3)</i> The multilevel output qualities substantially reduce the voltage transients d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</i> /d <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</i> of the inverter output, which is known to reduce insulation and bearing stress in motors. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4)</i> The topology eliminates the vulnerability of large hard-wired battery packs to the weakest cells. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5)</i> The constant presence of the high voltage in conventional hard-wired batteries and the associated issues, e.g., during manufacturing, maintenance, and crashs are avoided because of normally-off FETs. We demonstrate the proposed motor drive on a 3-kW setup with eight battery modules.

Photovoltaic-energy storage-integrated charging station retrofitting: A study in Wuhan city

In this study, an evaluation framework for retrofitting traditional electric vehicle charging stations (EVCSs) into photovoltaic-energy storage-integrated charging stations (PV-ES-I CSs) to improve green and low-carbon energy supply systems is proposed. Using existing EVCSs in the “10-minute living circle residential areas” of seven central urban districts in Wuhan city, we comprehensively consider factors such as the site distribution, sky view factor and service population to assess the economic and environmental benefits of PV-ES-I CS systems at different locations and scales. The research results show that the central urban districts have high retrofitting potential, with 44 stations north of the Yangtze River and 20 stations south of the Yangtze River being most suitable for retrofitting. The economic and environmental benefits vary significantly across building types; the retrofitting/construction of PV-ES-I CSs near hotels yields the greatest economic benefit and carbon dioxide emission reduction per unit investment.

A K-Additive Fuzzy Logic Approach for Optimizing FCS Sizing and Enhanced User Satisfaction

Traditional electric vehicle (EV) charging methods can lead to extended waiting times for users, resulting in decreased travel efficiency and user satisfaction, therefore impacting overall convenience. Moreover, a limited number of charging stations can lead to congestion, exacerbating waiting times, while an excessive number of stations incurs inefficient costs and reduces utilization. While prior research has primarily focused on sizing and allocating charging stations to enhance user performance, there has been comparatively less emphasis on optimizing waiting times and determining the optimal number of charging stations, which is crucial from the EV user’s perspective. This study introduces a K-additive fuzzy logic algorithm to predict the average waiting time and the optimal number of charging stations. The K-additive fuzzy inference system (K-FIS) defines membership functions, expert rules, and a formulation for achieving the optimal solution. The proposed approach integrates uncertain and independent input parameters into weighted control variables, addressing the objective function to optimize EV waiting times and costs represented by the number of charging stations. The scheme utilizes both Type 1 and Type 2 membership functions, offering a detailed comparison. To validate its efficiency, the proposed scheme undergoes a comparative study against related state-of-the-art approaches.

Ultra-Short-Term Load Forecast of Charging Stations Considering the Travelling and Charging Behaviours of Electric Vehicles

The traditional electric vehicle (EV) load forecasting methods are mostly used to predict large areas such as cities, which makes it difficult to serve practical applications. The existing charging station load forecasting methods ignore the traveling and charging behaviors of EVs. To this end, a charging station ultra-short-term load prediction method considering the traveling and charging behaviors of EVs is proposed. Firstly, EV types are classified according to charging behaviors. On this basis, a rolling forecast model of the number of arrivals per unit time of each vehicle type is established, and then the impact of charging randomness on load forecast is reduced by repeated Monte Carlo sampling. The total load of charging stations during the prediction period can be obtained by adding up the load of individual vehicles. The results show that the method enables accurate prediction of ultra-short-term load at charging stations, which has higher accuracy and reference value than the traditional load forecasting methods.

Optimisation of electric vehicle with the in-wheel motor as a dynamic vibration absorber considering ride comfort and motor vibration based on particle swarm algorithm

Compared with other electric vehicles, the ride comfort of the electric vehicle with the in-wheel motor as a dynamic vibration absorber has significantly improved. However, the in-wheel motor is used as a dynamic vibration absorber, aggravating the motor vibration, thus affecting motor performance and life. In addition, the space inside the wheel is limited, so the vibration displacement of the motor relative to the hub needs to be constrained. In fact, the literature on ride comfort of the electric vehicle with the in-wheel motor as a dynamic vibration absorber has hardly considered motor vibration. So, this article comprehensively investigates the ride comfort and motor vibration of this electric vehicle. Firstly, the vibration model of the electric vehicle with the in-wheel motor as a dynamic vibration absorber is established. Then, the optimisation model of this electric vehicle is founded. Next, the multi-objective particle swarm optimisation algorithms based on adaptive grid and crowding distance are used to optimise the model, and these two algorithms are compared. The optimal solutions in three typical cases are obtained. Finally, the vibration responses of this electric vehicle model before and after optimisation, the traditional electric vehicle model, and the in-wheel motor drive electric vehicle model are compared in case 1. The results show that all vibration responses are improved to different degrees after optimisation; the algorithm based on crowding distance can seek out the optimal solutions faster, but it takes longer to complete the whole optimisation process.

Design and analysis of electric vehicle thermal management system based on refrigerant-direct cooling and heating batteries

A thermal management system (TMS) based on R134a refrigerant is proposed, which not only meet the thermal requirements of cabin, but also refrigerant-directly cool and heat battery. Compared with the traditional electric vehicle (EV) TMSs, an electronic expansion valve (EXV) is equipped after the battery cooling/heating plate in the refrigerant branch circuit. The mainly working modes of the TMS and their control methods are described in detail. The paper applies mathematical one-dimension simulation method to analyze the feasibility of mainly working modes, including battery preheating mode, mixed heating mode, low-temperature mixed heating mode. The results show that the TMS is completely feasible to balance the heat distribution between cabin and battery by controlling the EXVs opening. In the battery pre-heating mode, the relationship between refrigerant state of cooling/heating plate outlet and the battery temperature uniformity is analyzed, and a control strategy to improve the battery temperature uniformity is proposed. In low temperature environment, when the TMS switches from cabin heating mode to mixed heating mode, the cabin air temperature will drop sharply. This is because the battery temperature is too low, that pressure of TMS is too low to maintain the heating demand of the cabin.

BATTERY SWAPPING STATIONS FOR ELECTRIC VEHICLES

Battery swapping is a promising technology when compared with the traditional electric vehicle charging stations. The time spent at a battery swapping station might be similar to the time spent at a filling station. The article presents information on attempts to implement this solution, methods of battery swapping, infrastructure and operation of battery swapping stations, as well as the benefits and key challenges of the battery swapping technology.

Implementing Electromobility in Public Transport in Poland in 1990–2020. A Review of Experiences and Evaluation of the Current Development Directions

Public transport has undergone major changes in recent years. In particular, they relate to the issue of environmental impact. Due to the significant emission of pollutants from the economy, in particular from the transport segment, member states of the European Union have taken measures to limit its scope. Only low-emission and zero-emission vehicles are to be used in transport, and mainly those that are powered by electricity in public transport. The development of battery technologies has led to a revolution in the range and operational capabilities of electric buses in the last decade. They have become a seemingly easy alternative to traditional electric vehicles in public transport—trams and trolleybuses. This article presents the possibilities and limitations of the development of public transport in Poland based on electric buses. An attempt was made to review the literature and compare the possibility of the functioning of buses, trams and trolleybuses in the Polish socio-economic, environmental and technological conditions. The article was based on a literature query, an analysis of unpublished materials, and a qualitative analysis of national programs endorsing the idea of electromobility as well as an online survey on the perception of electric public transport. The main goal of the article was to identify and evaluate the possibilities of developing public transport in Poland with the use of electric buses. The main results of the work include the demonstration that the optics of the national and regional authorities in Poland are focused mainly on electric buses without a thorough analysis of the legitimacy of their operation, especially in small towns. The incentive in the form of subsidizing the purchase of an electric bus is sufficient for them, and the future effects of using electric buses are not investigated.

Application Combination of Virtual Reality Technology and Silent Intensifier Technology in Electric Vehicles

The development of the current era has also led to the gradual emergence of global issues such as environmental protection and energy. Alleviating these issues has become an aspect that every country has to consider. In terms of environmental protection energy, the vigorous development of electric vehicles is an important aspect of our country as a major automobile country to solve environmental energy problems. For this reason, the country has introduced many favorable policies on the popularization of electric vehicles. Domestic electric vehicle companies have also begun to pay more attention to the technological innovation and development of electric vehicles. With the increasing popularity of electric vehicles, electric vehicle technology has ushered in new challenges for electric vehicle companies in various countries. In exploring the silent intensifier technology of electric vehicles, the mature development of virtual reality technology has begun to play an important role in the breakthrough of electric vehicle technology. The use of virtual reality technology to improve the combination of silent intensifier technology in electric vehicles can expand the advantages of electric vehicles, more effectively and quickly manage the silent effect of electric vehicles, thereby improving the driver and the surrounding environment. The enjoyment effect, and make new contributions to the technological development of electric vehicles. The purpose of the research in this article is to analyze the combined application of virtual reality technology and silent intensifier technology in electric vehicles, and to make innovative developments in traditional electric vehicles. This article starts from the maturity of virtual reality technology, takes the current expansion and popularization of electric vehicles as the background, and promotes the innovative development of electric vehicle mute technology as a specific research object on the basis of relevant reality background and theory, and makes full use of the current rapid The development of virtual reality technology is a breakthrough in the innovative development of mute enhancers for electric vehicles. The experimental results show that virtual reality technology can make new developments to the traditional electric vehicle mute technology, and build a new mode of mute booster in electric vehicles.

A comparative 3-D transient electromagnetic, thermal and powertrain study of single rotor BLPMSM and dual rotor machine for electric propelled vehicle

This article addresses the benefits of novel dual rotor machine for automobile sector. In case of traditional electric vehicle technology, the vehicle has a single rotor electric machine that can able to perform motoring or regenerative operation and can be possible according to the energy available in the battery. To overcome the above-mentioned problem, novel electric machine design topology with dual operation of motor and generator at same instances of time is proposed with improved electromagnetic, thermal and mechanical transmission losses. The design can be possible by adopting 7.2 kW claw pole alternator and 15 kW brushless permanent magnet synchronous machine as a dual rotor machine considering in-wheel concept. The performance analysis of the machine is done by using finite element analysis technique. The electromagnetic compatibility of machine is performed by three-dimensional transient solver in MagNet software. The electromagnetic analysis of machine is improved by introducing notches in the stator and permanent magnets in the rotor. Based on the electromagnetic results, thermal analysis of machine is calculated by coupling transient analysis using ThermNet software. The simulation results of machine are validated by using electric vehicle Powertrain blocks. The real-time performance of the machine is tested with real-world drive cycle using simulation software. The result substantiates the novelty of this design for improving the driving range of the vehicle for electric vehicle applications.

Application of PV-assisted Intelligent Electric Vehicle Charging and Switching Power Station

Taking a new office area as an example, this paper introduces the design of power supply and distribution system for traditional electric vehicle charging pile. In view of the adverse impact of large-scale EVs load on the power grid, a photovoltaic charging and switching power station microgrid system is proposed, and intelligent dispatching is carried out through the energy management system. The scheme combines the development of clean energy with the supporting facilities of electric vehicle, which can effectively solve the problems caused by the connection between new energy and power grid, and improve the quality of power grid. The Energy Management Strategy reduces the impact of traditional charging stations on the urban distribution network and the consumption of urban electricity during peak period, and has higher economic benefits.

Dynamic Pricing Strategy of Electric Vehicle Aggregators Based on DDPG Reinforcement Learning Algorithm

The fixed service charge pricing model adopted by traditional electric vehicle aggregators (EVAs) is difficult to effectively guide the demand side resources to respond to the power market price signal. At the same time, real-time pricing strategy can flexibly reflect the situation of market supply and demand, shift the charging load of electric vehicles (EVs), reduce the negative impact of disorderly charging on the stable operation of power systems, and fully tap the economic potential of EVA participating in the power market. Based on the historical behavior data of EVs, this paper considers various market factors such as peak-valley time-of-use tariff, demand-side response mode and deviation balance of spot market to formulate the objective function of EVA comprehensive revenue maximization and establishes a quarter-hourly vehicle-to-grid (V2G) dynamic time-sharing pricing model based on deep deterministic policy gradient (DDPG) reinforcement learning algorithm. The EVA yield difference between peak-valley time-of-use tariff and hourly pricing strategy under the same algorithm is compared through the case studies. The results show that the scheme with higher pricing frequency can guide the charging behavior of users more effectively, tap the economic potential of power market to a greater extent, and calm the load fluctuation of power grid.

Dispatching fuel-cell hybrid electric vehicles toward transportation and energy systems integration

With an increasing integration of traditional electric vehicles (EVs), the ensuing congestion and overloading issues have threatened the reliability of power grid operation. Hydrogen has been advocated as a promising energy carrier to achieve a low-carbon transportation and energy (trans-energy) systems, which can support the popularization of fuel cell hybrid EVs (FCHEVs) while enhancing the flexibility of power grids. In this paper, we propose an optimal scheduling framework for trans-energy systems that evaluates the merits of hydrogen supply chain from water electrolysis, compressed storage and transportation to FCHEV utilization. A detailed FCHEV model is established, and mileage is modeled as a function of the stored electricity and hydrogen mass. A stochastic programming-based scheduling model is formulated, which minimizes the total cost of unit commitment and hydrogen supply chain. Dijkstra algorithm is adopted to search the shortest path for hydrogen transportation. Case studies demonstrate that FCHEVs can reduce the operation costs of the trans-energy systems and facilitate the accommodation of renewable energy compared to traditional EVs.

Evaluation of Vibration Characteristics and Theoretical Analysis for In Wheel Driving Electric Road Vehicle

Hub-motor driven electric vehicles consider the upcoming technology in the vehicle industry. It has several merits such as lightweight, good accelerator responsiveness, flexibility when designing different drivetrains, operated at most operative efficiency points, and increased space-saving compared with the traditional electric vehicle driven by a central motor. The energy demand around the world is increasing dramatically. So, the researchers seek to find alternatives to the non-renewable resources represented by fossil fuels. Electric vehicles are the most suitable vehicle to avail of this type of energy due to their high efficiency and zero fuel consumption and emission. The electric-powered vehicle is distinctive with low noise and vibration which improves the vibration characteristics compared with internal combustion engine vehicles. In this paper, eight degrees of freedom passive quarter car suspension system of an in-wheel drive powered electric vehicle equipped with a battery/ultracapacitor hybrid energy storage system is studied and analyzed. The system was simulated and tested in both time and frequency domains via the MATLAB/Simulink environment.

The Control Strategy Research of 4WID Vehicles Steering-by-Wire System

Once the traditional electric vehicle was refitted with distributed drive (4wid) system, the increasing of vehicle’s unsprung mass would significantly increase the steering resistance, as a result of that, the efficiency and accuracy of the original car’s steer-by-wire (SBW) system will be reduced. In order to solve this problem, taking BAIC-EV150 for example, this paper introduced a design of SBW control strategy for 4WID vehicles, and the corresponding refitting work of real vehicle were completed. The refitted vehicle adopted dual-motor, dual-controller to coordinate control the output torque, aiming at compensating the resistance moment. Simulation and experimental results show that the controller can meet the requirements of 4WID vehicle steering, and the dual-motor steering system based on fuzzy PID control is more responsive and more accurate than the single-motor steering system which under ordinary PID control.

Study on Global Parameters Optimization of Dual-Drive Powertrain System of Pure Electric Vehicle Based on Multiple Condition Computer Simulation

Equipped with two power sources, the dual-driving powertrain system for pure electric vehicles has a driving mode different from traditional electric vehicles. Under the premise that the structural form of the transmission system remains unchanged, the following transmission schemes can be adopted for double drive electric vehicles according to the demand power: the main and auxiliary electric transmission scheme (two motors are driven separately with dual-motor coupling drive), the transmission scheme in which the two motors always maintain coupling drive, and the speed-regulating type electric transmission scheme (the main motor is always responsible for driving, and the auxiliary motor is responsible for speed regulation). Therefore, a significant difference exists in the design methods of the power transmission system of double drive electric vehicles and existing vehicles. As for such differences, this paper adopts intelligent algorithm to design the parameters of the transmission system and introduces the genetic algorithm into the optimization design of parameters to obtain the optimal vital parameters of the power transmission system based on computer simulation. The prototype car used in this paper is a self-owned brand car; MATLAB/Simulink platform is used to build the vehicle simulation model, which is used for the computer simulation analysis of the vehicle dynamic performance and economy. It can be seen from the analysis result that the system parameters obtained by using the global optimization method proposed in this study can improve the vehicle dynamic performance and economic performance to varying degrees, which proves the efficiency and feasibility of the optimization method.

The choice of a performance criterion for a high-voltage battery of a vehicle

Currently, major vehicle manufacturers are working to improve environmental friendliness by introducing alternative energy in motor vehicles: vehicles with combined power plants (hybrids) based on ICE, electric vehicles based on promising current sources like electrochemical generator based on fuel elements of “hydrogen-air” and traditional electric vehicles. All of the above vehicles use High-voltage battery running. The use of batteries in hybrid vehicles and electric vehicles puts forward certain requirements for them: large specific energy capacity; high resource indicator; fairly low cost. This article seeks a criterion for the performance of a high-voltage battery used as an energy source in electric vehicles. Performed an analysis of scientific publications and experiments describing the dependence of the parameters of the battery on the temperature and operating mode of the vehicle. The main parameters are determined and an assessment of their impact on vehicle performance is carried out.

A Secure Charging System for Electric Vehicles Based on Blockchain

Smart grids incorporating internet-of-things are emerging solutions to provide a reliable, sustainable and efficient electricity supply, and electric vehicle drivers can access efficient charging services in the smart grid. However, traditional electric vehicle charging systems are vulnerable to distributed denial of service and privileged insider attacks when the central charging server is attacked. The blockchain-based charging systems have been proposed to resolve these problems. In 2018, Huang et al. proposed the electric vehicle charging system using lightning network and smart contract. However, their system has an inefficient charging mechanism and does not guarantee security of key. We propose a secure charging system for electric vehicles based on blockchain to resolve these security flaws. Our charging system ensures the security of key, secure mutual authentication, anonymity, and perfect forward secrecy, and also provides efficient charging. We demonstrate that our proposed system provides secure mutual authentication using Burrows–Abadi–Needham logic and prevents replay and man-in-the-middle attacks using automated validation of internet security protocols and applications simulation tool. Furthermore, we compare computation and communication costs with previous schemes. Therefore, the proposed charging system efficiently applies to practical charging systems for electric vehicles.

Wireless Power and Bidirectional Data Transfer Scheme for Battery Charger

Wireless battery charging has been becoming a recent trend in mobile devices. However, there are relatively less research efforts focusing on the large power applications. It is a major drawback of the battery charging in traditional electric vehicles which relies on the use of a plug-in charging device. This paper proposes a wireless power and bidirectional data transmission scheme, data related to battery status, vehicle identification number, or emergency messages that can be mutually transmitted between two isolated units via the same LC tank. The primary unit employs an inverter to yield alternating current and power flow to the load via mutual inductance. The secondary unit transfers data by adjusting current of load, and the primary unit receives data based on the zero-voltage switching method. The primary unit transfers command by trimming the current's curve and the secondary unit receives command and make decoding using the period of carrier wave. It is worth to mention that the design scheme enables it to handle the situation of emergency by sending back the message to the primary unit to make an emergency halt.

Simultaneous Wireless Power/Data Transfer for Electric Vehicle Charging

The major drawback of the battery charging in traditional electric vehicles is the use of plug-in charging devices. The aim of this paper is to propose a wireless battery charging method, in addition to power transfer, data related to battery status, vehicle ID code, or emergency messages can be simultaneously transferred between the grid and vehicle. This work applies inductive power transfer to complete the charging system. The proposed control system can monitor the operating status on the secondary (vehicle) side in real time and adjust charging current depending on the battery status. Furthermore, the proposed mechanism is able to make an immediate stop, if there is any contingency, such as overcharging voltage or current. This will be beneficial to efficient and safety concern during the charging process.