Small Electric Car Research Articles

SEPIC Based BLDC Motor Control for Electric Vehicles

Abstract: This paper presents a BLDC motor that can be utilized in electric vehicle applications where speed control is necessary. It is driven by a single-ended primary inductive converter (SEPIC). The inverter that feeds the motor uses PWM-based switching; however, a SEPIC converter in the DC link can be used to adjust the voltage level. Electronic commutation gating pulses are provided to the inverter input and the DC input. It is effective for electric vehicles since it uses a converter that switches to manage voltage. The SEPIC is lightweight and suitable for use with small electric cars. This paper describes using a SEPIC converter to drive a BLDC motor. The BLDC motor's closed-loop speed control is modelled using MATLAB /SIMULINK, and the simulation's outcomes are presented.

Assessing the Dynamic Performance and Energy Efficiency of Pure Electric Car with Optimal Gear Shifting

Traditional pure electric cars generally adopt single-speed transmission for cost consideration. However, with the renewal and iteration of technology, small electric cars are all developed in the direction of power performance and environmental protection. Gear shifting makes it possible for the motor to work in a more efficient range, which possibly improves the performance of the entire powertrain. In this paper, a small electric car is designed, its power parameters are matched, and the energy-saving space and effect brought by adding multiple-gear shifting transmissions are discussed. To begin, the power-matching design was carried out, and then the transmission ratio was determined by particle swarm optimization. Finally, the power performance and fuel economy of this designed car equipped with different types of transmissions were analyzed and compared through simulation experiments. The results show that the electric car equipped with two-speed transmission has improvements in most important indicators, among which the acceleration time of 0 to 100 km/h is decreased by 17.7%, and the power consumption is reduced by 1.8%. To sum up, the feasibility of applying multiple-gear shifting to small electric cars is verified, and the experimental results provide a valuable reference for the development of electric cars.

Transmission Design and Control Optimization of an Electric Vehicle Using Analytical Modeling Methods

This paper introduces a framework to systematically optimize the design and control of an electric vehicle transmission, connecting powertrain sizing approaches with low-level gearbox design methods. To this end, we first create analytical models of the individual transmission components: gears, shafts, bearings, clutches, and synchronizers. Second, we construct a transmission by systematically configuring a topology with these components. Third, we integrate the composed transmission within a powertrain and vehicle model, and compute the minimum-energy control strategies and design, employing two solution algorithms, namely dynamic programming and exhaustive search, respectively, providing global optimality guarantees. Finally, we carry out the design and control optimization of a one- and two-speed transmission for a small electric family car, whereby we observe that a two-speed transmission can improve the energy consumption by 0.5% with respect to a one-speed transmission, whilst also satisfying the gradeability and performance requirements.

An empirical analysis of electric vehicle cost trends: A case study in Germany

This study conducts a learning rate analysis on electric vehicle retail prices in Germany between 2015 and 2020 to predict the point of purchase price parity between electric cars and comparable conventional vehicles in different market segments. In small cars, a learning rate of 23% was found. For mid-sized cars, the rate of cost decline was 29%. A learning rate of 24% was observed in the luxury segment. Based on these results, it was found that luxury BEVs would reach price parity by the year 2023, and that midsized vehicle would follow by 2026. For small cars, the results indicate that price parity will not be achieved before the year 2030. The price parity results are complemented with an evaluation of the present and future total cost of ownership of electric and conventional cars. The analysis found that in 2020, mid-size and large electric vehicles were already close to price parity with conventional cars, even before subsidies provided by the German government. Small electric cars still required significant subsidies to be cost-competitive, however. The sensitivity of the analysis results to certain key parameters was evaluated, including the standard error of the learning rates, expected global BEV production in future years, the cost of conventional powertrains, and the effect of government subsidies on the ownership cost, and the duration of the vehicle ownership period. Overall, the results suggest that while the cost gap in larger cars will be closed around the middle of the decade, a higher rate of technological innovation is needed to make small BEVs cost-competitive with gasoline cars before the year 2030.

Manufacturing A Personalised Composite Material Driver’s Seat

The paper presents the process of 3D-printing and laminating a composite material driver’s seat for Silesian Greenpower’s electric vehicle. Silesian Greenpower is a student’s interfaculty project, of which aim is to design, build and race a small electric race car. Aerodynamics and lightweight construction play a major role, so each element applied in the car is optimized and customized to fit in the vehicle. For this purpose, 3D-printing technology is often used by the team. A seat model made on the basis of the driver's anthropometric model was presented in the paper. Subsequently, after the appropriate adaptation of the obtained surfaces to interconnect them with each other, the FDM technology was applied using PET-G material. To increase the strength of the connections of the printed elements and to strengthen the design and stability of the chair, the element was laminated using carbon fibre and epoxy resin. The lamination process is presented and discussed in the article.

Experimental Analysis of Residential Photovoltaic (PV) and Electric Vehicle (EV) Systems in Terms of Annual Energy Utilization

Electrification of powertrain systems offers numerous advantages in the global trend in vehicular applications. A wide range of energy sources and zero-emission propulsion in the tank to wheel significantly add to electric vehicles’ (EV) attractiveness. This paper presents analyses of the energy balance between micro-photovoltaic (PV) installation and small electric vehicle in real conditions. It is based on monitoring PV panel’s energy production and car electricity consumption. The methodology included energy data from real household PV installation (the most common renewable energy source in Poland), electric vehicle energy consumption during real driving conditions, and drivetrain operating parameters, all collected over a period of one year by indirect measuring. A correlation between energy produced by the micro-PV installation and small electric car energy consumption was described. In the Winter, small electric car energy consumption amounted to 14.9 kWh per 100 km and was 14% greater than summer, based on test requirements of real driving conditions. The 4.48 kW PV installation located in Poznań produced 4101 kWh energy in 258 days. The calculation indicated 1406 kWh energy was available for EV charging after household electricity consumption subtraction. The zero-emission daily distance analysis was done by the simplified method.

Urban logistics of small electric vehicle charged from a photovoltaic carport

The technology of photovoltaic solar cells can be combined with the technology of electric vehicles. During charging electric vehicles with Renewable Energy Sources (RES) as well as during their use to the atmosphere are not emitted any pollutions. The article presents a carport designed for charging electric vehicle. Paper analyzed the power course generated by the photovoltaic system in different weather conditions. As a result of the comparison with the current demands of the electric vehicle battery during the charging process the optimal way of battery charging process was discussed. Later in the article presents logistics research on charging battery of an urban vehicle used frequently by catering companies to distribute products. The authors’ aim was to determine the actual range of the small electric vehicle on a single charge, as well as to statistically compile driving parameters in conditions of urban traffic in Lublin. The process of using such a vehicle has been analyzed, including the necessary battery charging. On the basis of the tests results a set of recommendations for small electric cars users was made in order to help increase the range of the vehicles in traffic and lengthen battery life.

Insights into the characteristics of technologies and industrialization for plug-in electric cars in China

Plug-in electric vehicles (PEVs) have been seen by many countries as a solution to the fossil fuel consumption and urban air pollution problems of the transportation sector. PEV stocks climbed to 1 million in 2015 and doubled as of 2016. Although the global mass market is developing, developmental laws for the technologies and industrialization of PEVs still need to be identified. These laws are necessary for finding solution to the problems of PEV penetration in the future. On the basis of a characteristic analysis of global PEV marketing progress, it can be found that China is becoming the main player in PEV sales and market penetration. It has potential be the largest PEV market in the world in future. Although China has the advantages of market volume, there are still severe challenges for the further mass adoption of PEVs in China. Therefore, a comprehensive evaluation on the evolution of China's PEV industry and technology is desirable as a foundation for identifying key problems regarding market penetration, so as to devise a long-term national PEV strategy. This study are performed based on detailed PEV marketing and technological data to present an in-depth view. A three-dimensional (market penetration rate, constitution, and concentration) evaluation method is proposed, and the market-acceptance indicators and cluster analysis method are used to analyze the correlations between the all-electric range (AER) of PEVs and market acceptance. This research allows us to draw several conclusions: (a) initial PEV market penetration depends mainly on fiscal incentive policies, which also strongly influences the technological roadmap for PECs; (b) A0-and A-class sedans are the dominant models for individuals, and small battery electric cars (BECs) will hold a large market share for a long time; (c) range-extended-type plug-in hybrid electric cars (PHECs) are suitable and competitive for Chinese local companies; and (d) the acceptable cost-benefit AERs are 150–170 km for privately purchased BECs. Electric taxis, however, require the AER to be over 300 km.

Highly-Efficient Dendritic Cable Electrodes for Flexible Supercapacitive Fabric.

In the search for clothlike wearable energy-storage devices with both high energy density and high power density, metal fibers surrounded by micro metal dendrites, as current collectors, are either rooted inside a thick layer of carbon particles or wrapped with flowerlike nano NiO in a similar manner to the root or stem system of natural plants, to form dendritic cablelike negative or positive electrodes. These dendritic cable electrodes could be further combined or woven into flexible solid-type supercapacitive garland or fabric, together with cotton wires. Benefiting from the ultra large interface of the metal dendrites current collector, it can be charged up to 1.8 V, and give an energy density of 0.1408 mWh cm-2 and a power density of 3.01 mW cm-2, which is capable of directly starting a small electric car with a short and flexible piece of supercapacitor.

Kicking the Oil Addiction

Kicking the Oil Addiction

Optimal Design Techniques for Small Electric Car Operating in Common Urban Traffic

The paper deals with design technique for electric drive of the small e-car. The requirements on electric car (drive) were determined according to European driving cycle ECE15. This normative defines typical city driving cycle and is used for example for definition of consumption for conventional cars. The main goal of the presented design techniques isn't primarily design of the drive as a substitute of conventional drive for middle class car, but design of drive for small low weight car with minimal demands on power and torque of its traction drive. Simultaneously the parameters of the traction drive have to meet all necessary requirements for safety city traffic operation. All these goals are specified according to requirements of typical city traffic operation with the range up to 30 km and with only one person in the car. Streszczenie. W artykule analizowany jest naped do malego pojazdu elektrycznego w oparciu o europejską dyrektywe ECE15. Celem jest projekt samochodu z minimalnymi wymaganiami dotyczącymi mocy i momentu napedowego. Analizowane są wymagania dla jednoosobowego samochodu o zasiegu 30 km. Optymalny projekt malego samochodu elektrycznego wykorzystywanego w typowym ruchu miejskim

The Study of Friction Materials in Brake Pad of Small Electric Car

Two kinds of friction materials in small electric car were studied by optical microscope(OM), X-ray diffraction(XRD) and scanning electron microscope(SEM). A sample was composed by Fe-based materials, SiO2, Al2O3 as hard phases, graphite and CaS as lubrications and carbonate and sulfate as fillers. MgO in B sample can increase its hardness, high temperature resistance and friction resistance. The lubrications of B sample consist of graphite and ZnS.

Bicycle Evolution in China: From the 1900s to the Present

ABSTRACT This article examines four phases in bicycle evolution in China from initial entry and slow growth (1900s to 1978), to rapid growth (1978 to 1995), bicycle use reduction (1995 to 2002), and policy diversification (2002 to present). Two bicycle innovations, electric bikes, and public bikesharing (the shared use of a bicycle fleet), are also explored in this article. Electric bikes could provide a transitional mode on the pathway to bicycle and public transportation integration or to small battery electric cars. Four lessons have been learned from China's electric bike experience relevant to government policy and management. Public bikesharing represents an important step towards integrating the bicycle with bus, metro, and rail systems. Five early operational lessons have been identified from China's limited public bikesharing experience.

24V-500W급 소형전동차용 DC모터 속도 콘트롤러 개발

In this paper, a new motor driving circuit is designed to improve the output performance of DC motor, and a controller is developed with the designed circuit. By the designed driving circuit, a controller can continuously drive DC motors by a transformer which has switching signals of a self-generated circuit to operate it. And while the DC motor have a maximum velocity, the reference voltage can be maintained higher value than that of triangle voltage and it makes the DC motor driving transistor ON and maximum power. A 24V-500W DC motor controller is developed with the proposed motor driving circuit, and also a small electric car is made and the driving test of it is executed. The test results shows that it can continuously control go and back speed of motor with 12A driving current. And also, it is verified that the over current and heat detecting function is operating correctly and the rest value of the used battery can be displayed as 6 step from 20 to 100%.

Ultracapacitors in E-cars, YES or NOT

The article deals with problems of usage of ultracapacitors in electric vehicles. Connection of the ultracapacitor to the traction battery is described and simulation of the complex energy management of the small electric car is performed. Some recomadations in which cases it is suitable to use the ultracapacitor are included finally.

The Design and Simulation of Electric-Vehicle Charger Control Strategy

In this paper, we analysis vehicle power batteries of the small electric cars, especially on its changes in charge characteristics and electric-vehicle charger specificity control object, and design a new charging control strategy of electric-vehicle charger. MATLAB simulation results show the validity and rationality of the strategy.

Electromobility concept for racing cars based on lithium-ion batteries and supercapacitors

For the construction of an all-electric race car, all aspects from engineering design over cost estimation up to the road capability are illuminated. From the most promising batteries for electric vehicle propulsion, the state-of-the art and commercial availability of lithium-ion secondary batteries is critically discussed with respect to cycle-life and unfavorable charge–discharge conditions. A market-overview is given with respect to a small electric car. Different combinations of electric motors and a recuperation system have been investigated. Weight aspects of central drive systems were considered and compared with decentralized wheel-hub drives. As a result, a centralized high-speed drive train based on a permanent-magnet synchronous engine with high-energy magnets seems to be superior due to limited space for assembly.

Optimal Design and Control of a Wheel Motor for Electric Passenger Cars

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> An optimal design and control technology of a wheel motor is proposed for small electric passenger cars. The axial-flux sandwich-type disc motor is designed with a rotor embedded with neodymium–iron–boron (NdFeB) magnets and two plates of stators, and is directly mounted inside the wheel without mechanical transmission and differential gears. Sensitivity analyses are performed to choose critical design parameters, which are the most influential in design objectives, to maximize the driving torque, efficiency, rated speed, and to minimize the weight of motor under various constraints of size, materials, and power sources. The optimal driving current waveform is proven to be the same as the fundamental harmonic of the back electromotive force to produce maximum torque with least ripples. The finite-element refinement results in the motor prototype with a maximum torque over 38 kg<formula><tex>$\cdot$</tex> </formula>m and a corresponding torque density of about 1.72 kg<formula><tex>$\cdot$</tex> </formula>m/kg at the maximum allowable phase current of 50.25 A (rms). Two such rear driving wheels are able to drive a 600 kg passenger car to accelerate from 0 to 40 km/h in 5 s on a 15 degree incline. This dedicated wheel motor is applicable to pure or hybrid electric vehicles as a promising solution to the direct-driven electric vehicle. </para>

Shared, Small, Battery-Powered Electric Cars as a Component of Transportation System Sustainability

Six U.S. trends are explored that may change how transportation systems and resources are used: changing demographics; questions about the future of highway infrastructure and maintenance; greater interest in alternative means of transportation; growth of telecommunications technologies; movement toward “access to services” rather than “ownership of goods”; and renewed interest in urban living. It is believed that shared, small, battery-powered electric cars can provide high-quality, cost-effective mobility to replace trips made in conventional cars, offer a viable alternative for changing lifestyles resulting from these trends, and move our global transportation systems toward sustainability. Although this paper is primarily intended to stimulate discussion and suggest future avenues for research, descriptions and examples of shared-car systems using small electric cars that complement the six trends are included. Although the current effort has focused on North America, thinking is beginning to expand internationally because a sustainable transportation system is a global necessity. Any two of the six trends could well cause an evolution in the U.S. transportation system, but all six combined certainly will. Similar trends can be found in other developed countries. Developing countries face even more severe transportation problems due to lack of resources to solve these problems as they arise.

Evaluation Results of San Francisco Bay Area Station-Car Demonstration

Presented is a summary of the evaluation of the first 2.5 years (November 1995–March 1998) of the San Francisco Bay Area Station-Car Demonstration. The 40 station cars were small battery-powered electric cars used for access to and egress from the Bay Area Rapid Transit District stations and for other local trips. The demonstration was a preliminary test of a larger vision for solving several problems associated with line-haul mass transit. Its purpose was to determine the viability of electric vehicles for short, everyday trips in a variety of settings: between home and a station; between a station and a work site; and as pool cars used at work sites. Other short trips were encouraged during the workday or during evenings and weekends when the cars were at participants’ homes. The participants and their opinions of the concept before entering and during the demonstration are described. Modal shifts, air emission benefits, energy impact, and many nonquantifiable effects are presented. A “10,000 station car” scenario based on data from the demonstration is presented to show the impact of a larger station-car deployment. Many of the lessons learned from the experiment are presented with the overall conclusions.