Electric vehicle possibilities using low power and light weight range extenders

Electric cars have the disadvantage of a limited range, and drivers may experience a range anxiety. This range anxiety can be solved by adding a range extender. But, the range extender should be light so as not to significantly increase the weight of the original vehicle. In urban areas with dense traffic (usually developing countries), the average speed around cities is typically lower than 50km/h. This means, the rolling resistance losses are more important than aerodynamic losses, and a weight reduction results in a bigger electrical range. Therefore, smaller and lighter range extenders are of much interest. The contribution of this paper is to indicate the possibility of range extenders with less than 25 kg with a capacity of 150 to 200 cc to suit a condition where weight counts. In this paper, the cost, environmental and grid impacts of going electric are also discussed. The effect of high altitude and driving style on the performance of an electric vehicle is assessed. The challenges and opportunities of vehicle electrification between countries with decarbonated power generation and fossil fuel dominated power generation are highlighted. Throughout the article, the case of Ethiopia is taken as an example

Hybrid Energy Storage Systems for UAV Applications

Energy storage constraints limit the range and endurance of electric based unmanned aerial vehicles (UAVs). Solving the energy storage problem allows the adoption of UAVs on a much wider scale. A solution to the problem would ideally retain the significant performance and efficiency benefits of the electric based propulsion system. The contents of this study focused on solving the energy storage problem through research, experiment, and simulation based testing of the application of hybrid energy storage systems (HESS) to existing UAV designs. A review of literature was done exploring existing and future applications of electric based aircraft propulsion systems. Research was conducted on current energy storage technology limitations and potential hybrid energy storage design solutions. The solution allows bridging the gap to full adoption of electric propulsion. After extensive research, a passively controlled hybrid battery and supercapacitor configuration was chosen for experimental and simulation based evaluations. The experiment and simulation tested for key battery performance improvements using the HESS and its applicability to UAV designs. Results showed a significant reduction to the peak amperage and peak temperature of the battery under identical load profiles. The experimentally tested passive HESS did not show a reduction in energy consumption, but the active HESS simulation results did. The simulation results showed a theoretical gain of 8.8% for state of charge (SOC) for the battery. Equating the SOC to range improvement, a 10% increase in range was possible for the UAV tested

Design of a bidirectional energy buffer using a switched-capacitor converter and supercapacitors for an auxiliary EIS converter for fuel cell stacks

Fuel cell as an attractive clean energy source has gained a great deal of interest. To increase the durability and reliability of fuel cells, diagnostics systems that can detect degradation and faults inside fuel cell stacks in end applications are highly in need. Electrochemical impedance spectroscopy (EIS), among other methods, is a promising characterizing tool for diagnostics and condition monitoring of fuel cells. It was traditionally only applied to single-cell or short stacks at low-power levels and required special laboratory equipment, but was recently brought to high-power stacks too which was made possible by many technological advancements. This is mainly owing to a growing interest in performing in situ EIS as a non-destructive method without the need for dismantling the stack. Unlike traditional approaches which relied on extra equipment, converter-based EIS provides attractive solutions for this purpose. In this thesis, the design and utilization of a bidirectional energy buffer module composed of a switched-capacitor converter (SCC) and a supercapacitor string for a new auxiliary EIS converter solution is presented. The module is designed towards having a more compact auxiliary converter unit. The design of the proposed energy buffer module is investigated in detail and a guideline is provided considering the application-specific optimal conversion ratio, supercapacitor string capacitance, and the probable limitations imposed by high EIS frequencies on certain situations. In a nutshell, the proposed switched-capacitor converter module (SCCM) consists of a bidirectional high voltage-gain SCC connected with supercapacitor string helps with the compactness and miniaturization of the entire auxiliary EIS converter and eliminating the potential problems of electrolytic capacitors such as bulkiness and limited lifetime due to the impact of ripples. The SCCM energy buffer with a high voltage gain offers a high buffering ratio for utilizing supercapacitors as the energy storage device

Análise técnico-económica no uso de Fuel Cells em autocarros urbanos

Para avaliar os potenciais benefícios da implementação de uma solução de transporte público baseada em autocarros elétricos a FC, é necessário avaliar o seu desempenho em operação. Este estudo apresenta uma análise técnico-económica de vários modelos de autocarros com tecnologia FC.To evaluate the potential benefits of implementing a public transportation solution based on electric buses with FC, it is necessary to evaluate their performance in operation. This study presents a technical-economic analysis of several bus models with FC technology