Power Charging Research Articles

Evaluation of Electric Vehicle Charging Usage and Driver Activity

As the country moves toward electric vehicles (EV), the United States is in the process of investing over USD 7.5 billion in EV charging stations, and Indiana has been allocated $100 million to invest in their EV charging network. In contrast to traditional “gas stations”, EV charging times, depending on the charger power delivery rating, can require considerably longer dwell times. As a result, drivers tend to pair charging with other activities. This study looks at two EV public charging locations and monitors driver activity while charging, charge time, and station utilization over a 2-month period in Lafayette, Indiana. Over 4000 charging sessions at stations with varying power levels (350 kW, 150 kW, and 50 kW) were monitored, and the median charge time was between 28 and 36 min. A large variation in station utilization was observed at Electrify America charging stations that had a range of stations with 350 kW, 150 kW, and 50 kW available. The highest utilization rates by hour of day on average were observed at 25% at the 150 kW Tesla station. Driver activity during charging influenced dwell times, with the average dwell time of drivers who waited in their vehicles to charge being 10 min shorter than those who would travel to the shops. Rain in the forecast also impacted the number of users per day. Although there are no published metrics for EV utilization and associated driver activities, we believe examining this relationship will produce best practices for planning future investments in EV charging infrastructure as public and private sector partners develop a nationwide charging network.

Towards emission free construction sites in Northern Norway: Results from a regional survey

The concept of emission free construction sites (EFCS) has emerged as a prioritised measure to reduce greenhouse gas emissions from Norwegian construction activities. EFCS have been evaluated through several pilot projects in Southern Norway, whilst none are found in Northern Norway. This study aims to investigate the major barriers and success factors for developing EFCS-projects in Northern Norway through a digital survey amongst construction industry representatives. The results indicate that major barriers for EFCS implementation are related to limited access and capacity of electricity and power supply, and limited availability and high costs of emission free technologies. Similar challenges are identified from EFCS projects in Southern Norway, making the cold climate, poor infrastructure, and remote conditions in Northern Norway an amplifier of these challenges. The identified success factors are to a large extent aligned with the major barriers, emphasizing improved power supply and charging infrastructure, as well as increased availability of emission free technologies. Predictable and equal requirement specifications in public tenders that reward those who invest in emission free technology are requested, emphasizing the importance of implementing requirements. Further work is needed to gather experience from EFCS pilots in cold and remote areas.

Design Considerations with Different Shielding Barriers and HTS Resonance Coils for Wireless Power Charging Unit in High-Speed Magnetic Levitation Train

Design Considerations with Different Shielding Barriers and HTS Resonance Coils for Wireless Power Charging Unit in High-Speed Magnetic Levitation Train

Methods for Partial Discharge Calibration in Gas-Insulated Substations for HVDC Power Grids and Charge Evaluation Uncertainty

Methods for Partial Discharge Calibration in Gas-Insulated Substations for HVDC Power Grids and Charge Evaluation Uncertainty

Activating and stabilizing Co sites in CoP for triggering oxygen electrocatalysis in zinc-air battery

Catalysts with high activity and corrosion-resistance are desirable for oxygen reduction and evolution reactions (ORR/OER) in rechargeable zinc-air batteries (ZABs). Herein, via an etching-phosphating-annealing strategy, CoP is in situ formed in hollow carbon-nanobox, both of which are wrapped by a thin nitrogen-doped carbon layer (CoP/HNBs@NCL). Tannic acid etches ZIF-67 nanobox to release Co2+ and 2-methylimidazole to generate hollow structure. As-marked CoP/HNBs@NCL-2 (271.9 m2 g−1) exhibits robust activities towards ORR (half-wave potential of 0.88 V) and OER (overpotential of 0.36 V), which outperforms many non-precious metal catalysts due to the strong interactions between CoP and N-species and the smooth mass transfer via the porous hollow structure. Even at high potentials (OER), HNBs@NCL framework can still relieve the leaching of Co species (leaching ratio of 15.5 % after 6 h) to obtain high corrosion resistance and stability. Theoretical calculations reveal that N atoms enhance the electron delocalization degree of Co sites in CoP to lower energy barriers and balance adsorption free-energies of O-intermediates to enhance oxygen electrocatalysis. Notably, ZAB with CoP/HNBs@NCL-2 air-electrode exhibits high peak power density (139.8 mW cm−2) and charge–discharge cycling stability (132 h). This work presents a reliable protocol to design hollow electrocatalysts with desirable bifunctional activity and stability for ZABs.

Performance Evaluation of Emerging Perovskite Photovoltaic Energy-Harvesting System for BIPV Applications

Perovskite solar cells (PSCs) are emerging photovoltaics (PVs) with promising optoelectronic characteristics. PSCs can be semitransparent (ST), which is beneficial in many innovative applications, including building-integrated photovoltaics (BIPVs). While PSCs exhibit excellent performance potential, enhancements in their stability and scalable manufacturing are required before they can be widely deployed. This work evaluates the real-world effectiveness of using PSCs in BIPVs to accelerate the development progress toward practical implementation. Given the present constraints on PSC module size and efficiency, bus stop shelters are selected for investigation in this work, as they provide a suitably scaled application representing a realistic near-term test case for early-stage research and engineering. An energy-harvesting system for a bus stop shelter in Astana, Kazakhstan, demonstrates the potential performance evaluation platform that can be used for perovskite solar cell modules (PSCMs) in BIPVs. The system includes maximum power point tracking (MPPT) and charge controllers, which can supply PSCM energy to the electronic load. Based on our design, the bus stop shelter has non-transparent and ST PSCMs on the roof and sides, respectively. May (best-case) and December (worst-case) scenarios are considered. According to the results, the PSCMs-equipped bus stop shelter can generate sufficient daily energy for load even in a worst-case scenario.

Multi-objective control and optimization of a stand-alone photovoltaic power conversion system with battery storage energy management

This paper addresses the problem of controlling a stand-alone photovoltaic (PV) energy conversion system integrated with a battery energy storage system. The study focuses on a series association of PV panels, a DC/AC converter, a Li-ion battery, and a DC load. The intermittent nature of PV power and frequent variations in load demand decrease battery lifetime and its charging performance. To mitigate these issues, an efficient battery charge controller is proposed to instantaneously balance the PV power flow delivered to the DC load and the battery, ensuring optimal utilization of PV power and appropriate battery charging. Based on available solar power, battery state of charge (SOC), and DC load demand The controller adapts to three charging modes, namely, maximum power point tracking (MPPT) charging mode, constant current (CC) charging mode, and constant voltage (CV) charging mode. Additionally, a novel energy management algorithm is designed to ensure battery safety and determine the system’s mode of operation, considering weather conditions and load demand variations. Interestingly, no solar irradiation or battery SOC sensors are required for the implementation of the control system. Nonlinear and robust controllers are developed to provide the necessary control input laws for the management algorithm. The robustness and stability of the system are verified using the Lyapunov theory. Furthermore, the paper quantifies the performance of the proposed strategy through a comparative analysis using integral of absolute error (IAE) indices against two conventional control approaches. Simulation results validate the effectiveness of the proposed controller strategy, demonstrating its high performance and ability to meet the specified objectives. This work presents an innovative approach to enhance the efficiency and reliability of stand-alone PV energy conversion systems with battery storage, offering promising prospects for sustainable energy applications.

Aerodynamic Noise Characteristics of Axial Flow Fan in Narrow Space and Noise Reduction Based on Flow Control

Abstract The aeroacoustic characteristics of a power module in the electric vehicle charging pile is studied by experimental and numerical methods. In the free field, a single cooling fan mainly emits tonal noise, while the far-field noise of fans in parallel satisfied the superposition of incoherent sound sources. However, when two fans in parallel delivered air into the power module, the noise increased significantly, especially broadband noise. Referring to the power module, a narrow space model with cooling fan supplying air inward is constructed. The computational fluid dynamics results show that the mass flowrate of the fan is reduced due to the obstacles downstream, which weakens the heat dissipation performance. Part of the fluid forms reflux, interacts with the fan and strengthens the corner vortex. By setting guide holes on the casing near the flow blockage to arrange flow, the flow resistance is reduced and the total mass flowrate of the fan is increased by 2.5%. The reflux and corner vortex are dispersed, and the vortices develop downstream, thus reducing the interaction with the fan. The predicted tonal sound pressure level (SPL) decreases by 3.2 dBA based on acoustic analogy method. The broadband noise caused by shedding vortex is also predicted and discussed by a semi-empirical model. In the noise reduction experiment of the real power module, combining inlet bellmouth on the fan and guide holes on the casing, the total SPL was significantly reduced by 2.9 dBA. Especially, based on bellmouth, guide holes brought an additional 1.9 dBA tonal noise reduction and 1.0 dBA total SPL reduction. The study indicates that appropriate flow control is important to improve the heat dissipation and reduce noise of the power module. These results are helpful to develop higher power charging system.

Low Temperature Niobium Tungsten Oxides as Anodes for Fast Charging Li-Ion Batteries

The development of fast-charging Li-ion batteries is one of the important steps in building electric vehicles that need high power and fast charging. The reduction in the particle size to the nanometre length scale drastically improves the charging rate by increasing the surface area but lowers the volumetric energy density and can potentially result in more rapid degradation of the electrolyte via electrode-catalysed reactions. Recent reports show that niobium tungsten oxides (NbWOs) with µm sized particles serve as good anode materials for Li-ion batteries having high volumetric capacity with good cyclability at high rates while avoiding solid electrolyte interphase formation (SEI). The high rate performance of NbWOs is attributed to the topochemical charge storage mechanism that exhibits (i) minimal, highly reversible structural changes during the charge-discharge cycles, (ii) high Li-ion diffusion coefficients due to the presence of fast conducting tunnels, and (iii) high electronic conductivity upon lithiation.1,2 The NbWOs are known to crystallize into two families of different crystal structures depending on the composition and synthesis conditions. The NbWOs phases can either have tungsten bronze-type structures or block-type structures (commonly referred to as Wadsley-Roth phases). Different NbWO phases are reported in the literature3 which could serve as potential anode materials with better performance.In this work, a series of new NbWO phases have been synthesized at reduced annealing temperatures and the structure of these phases has been established using X-ray and neutron diffraction data. The electrochemical properties of NbWO/Li half cells were examined through a series of galvanostatic (dis)charge tests at varying current rates ranging from 0.2 C to 20 C. The NbWO phases delivers a high reversible capacity of 200 and 130 mAh/g at 0.2C and 10 C respectively vs. Li metal. Here we use operando powder X-ray diffraction to investigate the structural changes occurring at the anode during the charge-discharge process in the newly synthesised NbWO phases. Reference s : 1 K. J. Griffith, K. M. Wiaderek, G. Cibin, L. E. Marbella and C. P. Grey, Nature, 2018, 559, 556–563.2 C. P. Koçer, K. J. Griffith, C. P. Grey and A. J. Morris, Chem. Mater., 2020, 32, 3980–3989.3 N. C. Stephenson, Acta Crystallogr. Sect. B Struct. Crystallogr. Cryst. Chem., 1968, 24, 637–653. Figure 1

(Invited) Sub-Bandgap Thermoreflectance Imaging of Ultra-Wide Bandgap Semiconductors

Over the past few decades, wide bandgap semiconductors (WBG) have been used to fabricate high power and high frequency devices. Device structures, such as Gallium Nitride (GaN) High Electron Mobility Transistors (HEMTs), have begun to be implemented in commercial products such as electrical vehicles and laptop power chargers. With the continuous increase in energy demand, however, extremely high voltage (>10 kV) applications are needed to increase the grid resiliency, storage, and transmission efficiency. Ultra-wide bandgap (UWBG) Semiconductors, with bandgaps >4 eV, could potentially be used to overcome this barrier. Pushing the maximum voltage limit of these devices, however, can lead to significant power dissipation and excessive joule heating.Unfortunately, the thermal conductivity of some UWBG semiconductors, such as Gallium Oxide, is inherently low and thus requires both device and package level thermal management. Innovative solutions, such as high thermal conductivity substrates, are required to reduce the active channel temperature and extend the device lifetime and reliability. In order to successfully implement these technologies, accurate measurement of the peak temperature and thermal distribution (both vertical and lateral) is necessary. Depth-averaged vertical temperature gradients have been demonstrated via Raman thermometry but this approach can become significantly time consuming if attempting to perform transient or lateral maps. On the other hand, Transient Thermoreflectance Imaging (TTI) has shown the potential to provide high throughput thermal images with high spatial resolution (100 nm) and temporal resolution (50 ns).Traditionally, TTI has been used to probe the temperature of metals due to their inherent high reflectivity. Nevertheless, recent studies have demonstrated the ability to probe the surface temperature of the semiconductor when using near-bandgap illumination sources. Due to the high bandgap of UWBG semiconductors, the maturity of high transmission UV sources, optics and detectors has not yet been fully developed. This study investigates the applicability of sub-bandgap wavelengths to probe the active channel temperature. The thermal properties of both Gallium Oxide transistors and Transfer Length Method (TLM) structures are investigated using TTI. The accuracy of the channel temperature is assessed by direct comparison to the adjacent metal contact temperature. A finite element model (FEM) is developed to understand the thermal transport in low thermally conductive semiconductors. Finally, a 3D analytical model is used to extract thermal properties such as the thermal conductivity of the thin film layers.Figure a) Optical CCD Image of Gallium Oxide Transfer Length Method (TLM) Structure b) Transient Thermoreflectance Image (TTI) of Gallium Oxide TLM using sub-bandgap illumination wavelength. Figure 1

(Invited) Using Synchrotron Techniques to Pry into Lithium-Ion Batteries Limitations

Li-ion batteries have been highly successful since they were introduced commercially some 30 years ago. However, there are still improvement to be made to reduce cost, charging times, energy density etc. In this talk, we will present the some of our recent synchrotron radiation-based work on the sub-processes that must work in unison for lithium battery operation, in particular at high current densities. Specifically, we will present work at the particle level on high power charging, illustrating how under favorable conditions some commercial cathode materials may be fully charged within tens of seconds. Moving towards the electrode scale, our latest technique development include an x-ray fluorescence technique that permits the determination of the electrolyte concentration within the electrode during battery operation. As such, this represent a major step forward towards validating mesoscale modeling as well as testing novel electrode architectures specifically designed for improved electrolyte transport. The importance of the electrode design is that in theory it can provide higher active material loading per area without losss of power capabilities. As such, the mass and volume of separator as well as current collector could be minimized improving both energy density and cost.

Solar Powered Charging of Fuzzy Logic Controller (FLC) Strategy with Battery Management System (BMS) Method Used for Electric Vehicle (EV)

Solar Powered Charging of Fuzzy Logic Controller (FLC) Strategy with Battery Management System (BMS) Method Used for Electric Vehicle (EV)

Operating Characteristics of Wireless Multi-Charging Module Based On Multi-Magnetic Resonance Couplings for High Speed Superconducting MAGLEV Train

The various wireless power charging (WPC) units for high speed train such as superconducting magnetic levitation (MAGLEV) and hyperloop train should be practically required to supply electric power without overhead wire power lines of pantographs, since such a unit can reduce the construction cost for pantographs, which charge electric power for superconducting levitation and electric devices inside of traveling train. The wireless charging technology via magnetic resonance method can be able to enable the wireless charging for multiple charging using multiple resonance frequencies from watts or more even meter-level distance. The interference effect for multi resonance frequencies among multi resonance coils should be investigated to design the structure of optimized coupled coils and keep stability. In this paper, authors investigated the intensity and distribution of electric and magnetic fields, as well as thermal distributions for multi magnetic resonant couplings (MRC-WPC) system with multi-resonance frequencies under magnetic shielding structure. In order to examine the interference effects by multi-electromagnetic propagations, charging characteristics for the multi-resonance coupling structure including HTS resonance coil were measured using 100, 370 and 750 kHz power sources.

Design and Analysis of Misalignment Insensitive Wireless Power Transfer System Based on Multitransmitter for Constant Power

This paper proposes a multiple transmitting array wireless power transfer (MTA-WPT) system with constant output power charging for consumer electronics, such as tablets and mobile phones. Compared to conventional WPT systems, this proposed system can achieve constant output power by controlling the current phase shift of the transmitting (Tx) coils when the receive (Rx) coil is located at different positions and directions. The detailed circuit topology of the proposed system is modeled and analyzed to obtain the correspondence between the current phase shift and load output power. Furthermore, the excitation current distribution strategies for a system of three and four Tx coils at optimized efficiency are theoretically analyzed. The simulation demonstrates that the proposed system can achieve constant output power with modulating the phase shift at various Rx sites. Finally, an experimental prototype with four Tx coils is designed and carried out to prove the effectiveness of the phase shift modulation method and current distribution strategy. Besides, the superiority of the proposed MTA-WPT system is verified by comparison with other methodologies. The experimental results show that the output power of Rx at different positions is kept at roughly 41W with the transmission efficiency over 80% by the Tx current phase shift modulation.

Electric‐Dipole Gated Two Terminal Phototransistor for Charge‐Coupled Device

AbstractThe demand for charge‐coupled device (CCD) imagers has surged exponentially during the last decade owing to their exceptionally high quality and low noise imaging. However, they are still confronting the performance constraints of high operation power, low speed, and limited charge integration. Here, the electric‐dipole gated phototransistor operation without external gate bias is reported by using high‐k HfO2 dielectric material. The electrostatic coupling of photogenerated charges from the Si with the graphene channel through a 10 nm HfO2 layer is demonstrated. The device exhibits remarkable performance in the broadband spectrum (266–1342 nm) at low drain bias voltage. The high values of responsivity, external quantum efficiency, and detectivity of 3.7 × 103 A W−1, 0.72 × 104, and 6.20 × 1013 cmHz½ W−1, respectively, for 800 nm wavelength and 3.3 × 103 A W−1, 1.31 × 104, and 5.61 × 1013 cmHz½ W−1, respectively, for 400 nm wavelength without gate are achieved. This discovery may potentially eliminate the requirement for gate terminals from commercial CCD devices. The power efficient features of this gateless image sensor can be fabricated at the industrial scale for the future machine vision market.

Seasonal electric vehicle forecasting model based on machine learning and deep learning techniques

In this paper, multiple featured machine learning algorithms and deep learning algorithms are applied in forecasting the electric vehicles charging load profile from real datasets of Spain's electrical grid. The study aims to provide realistic datasets of electric vehicle load profiles to cope with the potential increase in electric vehicle penetration taking into consideration the seasonality effects. Technical issues are caused by the distribution network of the electricity grid; such as the huge charging power and stochastic charging behaviors of the drivers of electric vehicles due to the mass rollout of electric vehicles. Forecasting electric vehicles’ load profile is necessary to face challenges to solve the problem of the potential mass rollout of electric vehicles penetration. However, Electric vehicle is considered one of the most promising solutions that develops faster than other stochastic renewable solution to reduce greenhouse emissions. The seasonality effect is one of the huge challenges on electrical loads, so it is investigated by creating four separate forecasting networks to increase system accuracy and studying the effect of seasonal factors such as temperature fluctuation in the four seasons affecting the electric vehicles’ battery in charging and draining modes. These factors are affecting the accuracy of the forecasting model. Four featured algorithms are investigated. Artificial Neural Networks and Adaptive Neuro-Fuzzy Inference Systems are applied as machine learning algorithms, and Long Short-Term Memory and the Gated Recurrent Units are also utilized as deep learning algorithms. The Gated Recurrent Units model performs slightly better than the long short-term memory employed on the hourly average daily historical data of charging electric vehicles. While the Adaptive Neuro-Fuzzy Inference System gathers both Artificial Neural Network and Fuzzy Inference System advantages.

Fixed Frequency LCC Resonant Converter Modeling and Optimal Design for High-Voltage Capacitor Charging Power Supply in Constant Power Control

LCC resonant converter is widely used in high-voltage capacitor charging power supply(CCPS) due to its high efficiency and utilization of parasitic parameters. Since CCPS generally demand a wide voltage variation range, the conventional frequency modulation is difficult to scale up in constant power control. In this paper, a phase-shift(PS) LCC resonant converter in constant power control is proposed. To solve the deviation of the shifted phase of the traditional method in constant power control, an accurate model based on state plane analysis(SPA) is built. On this basis, an optimal design method of PS-LCC for CCPS is proposed, which is helpful to realize the soft switching and reduce the current peak. Finally, a 10kV CCPS prototype is built. And experiment designed by proposed method realizes the constant power charging in PS-LCC for the first time. Experimental results show that the charging speed is increased by 44.3% compared with the traditional constant current charging. Besides, the current stress is reduced by 24.1% and the soft-switching range is extended by 6.9%. There is valuable engineering guidance for realizing high-efficiency and high-speed CCPS by the design method proposed.

Solar Powered Battery Charging System by Using Arduino: Experimental design

In recent years, the need for efficient and sustainable energy solutions has become increasingly important. One potential solution is the use of solar power for battery charging systems. In this project, an Arduino-based solar-powered battery charging system is designed and implemented. The system consists of a solar panel that collects energy from the sun, an Arduino microcontroller that regulates the battery's charging, and a battery that stores the energy for later use. The solar panel converts sunlight into DC electrical energy, which is then fed to the battery through a charging circuit. The implementation of this system is fairly straightforward. The solar panel is connected to an input pin of the Arduino microcontroller, which then controls the charging of the battery through a charging circuit connected to an output pin. The charging circuit is designed to limit the charging current and voltage to prevent damage to the battery.

Supertwisting sliding mode controller for grid-to-vehicle and vehicle-to-grid battery electric vehicle charger

The battery electric vehicle charger offers an efficient bidirectional interface for the charging and discharging of the battery in both grid-to-vehicle (G2V) and vehicle-to-grid (V2G) modes respectively. The effective supervision of power flow is very complicated in any mode of operation. In this work, a super-twisting sliding mode-based controller (ST-SMC) is proposed for the control of a BEV charger power converters to track the required current and voltage in both charging (G2V mode) and discharging (V2G) processes. The chattering effect is a very serious issue in power converters, which is mitigated by the proposed controller. The Lyapunov stability criteria is used to evaluate the system stability. The safety and effectiveness of the proposed controller have been demonstrated through hardware-in-loop (HIL) based experimental verification employing the Delfino F28369D dual core micro-controller. MATLAB/Simulink is used to simulate the proposed controller.

A PV variability tolerant generic multifunctional control strategy for battery energy storage systems in solar PV plants

This paper proposes a multifunctional control strategy for battery energy storage systems (BESSs) in solar photovoltaic (PV) plants to avoid the unacceptable PV-power ramp-rate caused by PV variability. In addition to the PV variability tolerant ramp-rate control, the proposed multifunctional BESS control strategy is capable of maintaining a user-specified charging profile to store excess PV power while providing backup power support and charge maintenance, by accommodating diverse control functions time to time. Four control functions, namely, Rest (RST), Surplus Energy Storage (STR), Back-up Power Support (SPT) and Charge Maintenance (CMT) functions, are proposed in this article. Besides, extendibility of the proposed multifunctional strategy is presented by adding two action strategies – one with the STR function and another with the SPT function. Validation of the proposed control strategy is conducted by using real historical data from a utility-scale solar PV plant located in Queensland, Australia. Numerical analyses show that the strategy can successfully keep the PV ramp-rate within specified limit along with the user specified charge profile. Further, exploiting the real-field data, the proposed strategy is demonstrated through a real-time co-simulation study conducted in a MATLAB interfaced RSCAD-RTDS platform that can be used as Digital Twin (DT) for the PV plant.