Search

Wireless power transfer (WPT) has drawn a lot of attention due to its significant advantages such assafety, reliability, weather proof, etc. This paper presents the design methodology of a WPT converterwith LC/S compensation topology for electrical vehicle (EV) battery charge applications. The powerloss analysis is employed for each component in the WPT converter. The components in the converterare determined based on low power loss and high-power efficiency. The Lithium- ion battery is alsopreferred in the design due to it’s high power density advantage. Since the designed WPT system doesnot use a dc-dc converter to regulate the output current and voltage, the size and the weight of theoverall system can be reduced. Finally, according to given design procedure, a field-electric commonsimulation of WPT converter is performed with 2 kW output power while the output voltage ischanging between 250 V-400 V. The simulated peak efficiency of the converter is obtained around96.70% with 0.3 coupling coefficient.

For electric vehicle (EV) battery chargers, inductive power transfer (IPT) has become popular day by day due to its features such as being safe, comfortable and weather proof. The constant current (CC) and the constant voltage (CV) charge control modes are important for high-efficiency charging and long-life use of Lithium-ion (Li-ion) batteries commonly used in EVs. However, IPT method requires a wide range of operating frequency in order to provide CC/CV charge control modes. In IPT applications, CC and CV charge control modes are mainly achieved with dc-dc circuits using compensation networks at the transmitter and receiver sides. In this study, performances of inductor-capacitor/series compensation and double-sided inductor-capacitor-capacitor compensation topologies are evaluated based on CC/CV charge control modes. The analytical evaluation is presented in terms of voltage and current regulations during the entire charge control period. Finally, presented analytical evaluation is confirmed with ANSYS software providing field-electric common simulation to predict real response of compensation topologies. In the simulation work, both compensation topologies are operated for the maximum 2.5 kW output power and at the 250 V-450 V output voltage range. © The Author(s) 2020.

The paper deals with the design of an active battery charge balancing system for Li-ion batteries. The Li-ion batteries are sensitive to series connection and thus some sort of balancing system must be implemented in battery packs and modules. An active system for batteries balancing based on flyback converter is chosen to deal with this issue. In the first part of the paper a brief presentation of the issue and proposal of system solution is given along with simulation verification. The second part of the paper provides insight into a design together with a hardware and software solutions, mainly focusing on subsystems and initial choice of components. Finally, an experimental verification is conducted for presented design approval.

This work presents detailed analysis of LLC resonant converter to accurately predcit the voltage gain of the converter. Nowadays, Lithium-ion battery cells are mostly preferred for on-board electrical vehicle (EV) battery chargers due to their high power density. This results in wide range output voltage regulation for battery charger. The output voltage regulation of LLC resonant converter is provided by the changing of switching frequency. However, conventional first harmonic approximation (FHA) method applying for resonant power converters produces error below resonance frequency. Therefore, the objective of this paper is accurate prediction of the voltage gain characteristic for LLC resonant converter using in EV battery charge applications. The detailed theoretical anlysis of the LLC resonant converter is presented and the presented analysis is compared with a simulation study with 2.7 kW output power and 250 V-450 V output voltage range.

The orbital characteristics of low Earth orbit (LEO) satellite systems prevent continuous monitoring because ground access time is limited. For this reason, the development of simulators for predicting satellite states for the entire orbit is required. Power-related prediction is one of the important LEO satellite simulations because it is directly related to the lifespan and mission of the satellite. Accurate predictions of the charge and discharge current of a power system’s battery are essential for fault management design, mission design, and expansion of LEO satellites. However, it is difficult to accurately predict the battery power demand and charging of LEO satellites because they have nonlinear characteristics that depend on the satellite’s attitude, season, orbit, mission, and operating period. Therefore, this paper proposes a novel battery charge and discharge current prediction technique using the bidirectional long short-term memory (Bi-LSTM) model for the development of a LEO satellite power simulator. The prediction performance is demonstrated by applying the proposed technique to the KOM-SAT-3A and KOMSAT-5 satellites operating in real orbits. As a result, the prediction accuracy of the proposed Bi-LSTM shows root mean square error (RMSE) within 2.3 A, and the prediction error well outperforms the most recent the probability-based SARIMA model.

With technological advancement, the automobile industry is undergoing a design evolution. There has been an increase in the use of electrically actuated systems; electronics-based control systems, ...

In this paper, we propose a solution to the complete vehicle energy management problem with battery charge acceptance limitations and battery aging limitations. The problem is solved using distributed optimization for a case study of a hybrid heavy-duty vehicle, equipped with a refrigerated semi-trailer for two different battery models. The first battery model takes charge acceptance into account by adding an additional energy state to the optimization problem. The second battery model includes battery aging for which a novel iterative algorithm is proposed. Simulation results show that charge acceptance limitations only have a minor effect on the solution to the energy management problem, while battery aging leads to a trade-off between battery capacity loss and fuel consumption reduction. In particular, a decrease in capacity loss by 260%, leads to a drop in fuel consumption reduction from 9.40% (without battery aging) to 8.61% (with battery aging), both when compared to a conventional vehicle. This is caused by the fact that aging limitations cause less energy to be stored in the high-voltage battery. Still, because energy can also be stored in the refrigerated semi-trailer, smart control of this refrigerated semi-trailer leads to an additional fuel reduction 0.53% in the case where battery aging is incorporated, while it was only 0.09% when battery aging was not considered. In other words, the drop in the fuel consumption reduction caused by battery aging constraints can be partly compensated by smart control of other energy buffers, which shows the true benefit of complete vehicle energy management.

The battery management system (BMS) is indispensable for photovoltaic installations with storage because they optimize the use of batteries, protect them against damage and prolong their life. This paper presents a hardware platform for the experimentation of battery storage station. This platform contains a BMS for lead-acid batteries built around an Arduino Mega. The software of BMS allows, in addition to the functions of battery management and load control, to store the data in an excel sheet for later use.

The study of battery charge algorithm as a sole power storage agent in off-grid systems is essential. The battery charge algorithm has various methods, and the battery in these methods relies on the quantity of charges. Hence, a charge controller is used to safeguard and regulate battery charge and discharge for off-grid photovoltaic (PV) systems. This study presents the 11.4 kWp power plant analysis comprising three 3.8 kWp each of off-grid, hybrid and grid-assisted systems with battery capacities of 900 Ah, 1235 Ah and 910 Ah, respectively, where all the systems were reconfigured to function as off-grids. The battery charge controller charges the lead-acid battery using a three-stage charging strategy, including constant current, constant voltage and float charge stage. A DT80 data logger was installed to simultaneously record the electrical parameters of the systems, while Kipp & Zonen CMP 11 pyranometer was selected to measure solar radiation data. Experimentation with three electric bar heaters, each with fan and humidifier, were used as loads to draw constant power of 1.2 kW from batteries of each system on charging and discharging on an overcast and clear sky days for a week. The useful study is performed in the following ways, MPPT tracking performance, battery charging and discharging performance and charge controller efficiency. The performance results reveal that the MPPT can track the PV module maximum point at solar irradiance from 07h15 to around 12h00 maximum power tracking efficiency. An irradiance of illumination fluctuates from 5 W/m2 to 850 W/m2 while the electrical energy consumed by the loads in off-grid, hybrid and grid-assisted systems are 456.12, 568.87 and 80.00 Wh, respectively. It is estimated that individual owners could charge electric appliances from residential and commercial buildings of solar arrays of clean, renewable solar energy., Photovoltaics; Off-grid system; Battery system; Charge controller; Charge and discharge.

We discuss the application of classical variational methods to optimal charging/discharging strategies for a prosumer or storage supplier, where the price of electrical power is known in advance. We outline how a classical calculus of variations approach can be applied to two related problems: (i) how can a prosumer minimise the cost of charging/discharging a battery, when the price of electrical power is known throughout the charging/discharging period? and (ii) how can an electricity supplier incentivise desired prosumer/storage supplier behaviour by adjusting the price?

We develop a direct numerical simulation (DNS) model of multidisciplinary transport coupled with electrochemical reactions during Li-ion battery charge/discharge processes based on the finite volume (FV) numerical technique. Different from macroscopic models, the DNS model is based on microstructure of composite electrodes and solves component-wise transport equations. During DNS, the input physical properties are intrinsic material properties, not effective physical properties for macroscopic models. Since the interface of solid and electrolyte phase is evidently differentiated in DNS, the occurrence of electrochemical reactions is prescribed exactly on the interface of solid and electrolyte phase. Therefore, the DNS model has the potential to unravel the underlying mesoscopic pore-scale mechanisms of multi-disciplinary transport coupled with electrochemical reactions and thus can provide insightful information of the involved processes, as well as enables the design and optimization of electrodes, including microstructures inside electrodes. One test case, in which the electrode microstructure is reconstructed with a purely random reconstruction method, is considered. Simulation results corroborate the validity of the DNS model.

Large-scale battery systems have been applied to a number of grid-level energy storage services such as microgrid capability and distribution upgrade due to the penetration of solar/wind energy. In these battery applications, charge imbalance among battery cells/modules/packs becomes a common issue, which can reduce available battery capacity, accelerate battery degradation, and even cause some safety hazards. To tackle this issue, various battery charge equalization (BCE) systems have been proposed in recent decades, among which the module-based BCE system is widely viewed as a promising solution and has drawn increasing attention. In this paper, we study the module-based BCE systems by presenting a mathematical model that can characterize the charge transfer behavior in such systems, and then propose computationally efficient algorithms to estimate the instantaneous battery cell state of charge (SOC), charge equalization time, and charging/discharging time, based on given system parameters and various initial battery cell SOCs. In addition, the conditions are derived to ensure that all battery cells can reach charge equalization and then get fully charged/discharged together without overcharging/overdischarging. All theoretical results are illustrated and justified through extensive numerical experiments.

The widespread application of renewable energy has accelerated the development of microgrid technology and industry. As a typical application scenario of microgrid, the park-level microgrid with solar-battery-charge lays the foundation for enterprises to save energy, reduce consumption, improve efficiency, reduce fees, generate foreign exchange and income. In order to improve the operation efficiency and efficiency of the park-level microgrid, this paper firstly proposes the typical architecture of the park-level microgrid based on a large number of domestic and foreign related literature on the construction and operation of microgrid. Secondly, the economic dispatching and collaborative optimization model of the park-level microgrid with solar-battery-charge is constructed, and the corresponding solution algorithm is designed. Thirdly, the feasibility and effectiveness of the model and algorithm is verified by a park-level microgrid with solar-battery-charge. Finally, the conclusion of this paper is put forward and the future research is prospected. The research results of this paper can provide advanced experience and decision-making reference for the construction and operation of the park-level microgrid.

Context:Extension of battery lifetime on mobile devices is an aspect which is continuously studied by both manufacturers and applications developers. Problem: Most studies are focused on extending Li-Ion batteries lifetime (commonly used in mobile devices), on the premise that charge cycles in this kind of batteries do not reach 100% of their capacity. Aim: We have proposed an autonomous system to control the maximum charge level of a mobile device’s battery. The system also gathers/analyzes data regarding the battery charge cycles in real-time by using the open source FIWARE platform and the ESP8266 micro-controller. Methodology: We have performed a simulation of the battery charge cycle as a proof of concept. Results: The preliminary tests were performed on the prototype which allowed us (1) to maintain a relatively constant level of charge by automatically switching on and off the smart plug, (2) to send the charge and uncharge levels of the device in real-time through the an Android application, and (3) to display all information on a time series chart by using the grafana tool.

A tunable PNP-based ESD clamp is designed for a 4.5V power IO in a foundry technology. Using Mixed-Mode TCAD simulations, we show that the clamp's trigger and holding voltage can be easily tuned by simple layout modifications. The fabricated clamp was characterized using an on-wafer TLP system, confirming the tunable V t1 =13.4−16.8V, with V hold slightly above 10V and I t2 >1.2A. Finally, the clamp is combined with an off-chip transient voltage suppressors (TVS) to withstand surge stress on system-level.

Under the large-scale penetration of photovoltaic generation systems, the temperature constraints of transmission lines play a key role in the flexible operation of the power grid. In this paper, simplified line temperature constraints are derived from its physical model, and the strength and limitation of the simplified models are investigated. The features of the proposed models are further discussed based on the simulations of economic load dispatching control (EDC) and EDC recovering.

No legged walking robot yet approaches the high reliability and the low power usage of a walking person, even on flat ground. Here we describe a simple robot which makes small progress towards that goal. Ranger is a knee-less four-legged ‘bipedal’ robot which is energetically and computationally autonomous, except for radio controlled steering. Ranger walked 65.2 km in 186,076 steps in about 31 h without being touched by a human with a total cost of transport [TCOT ≡ P/mgv ] of 0.28, similar to human’s TCOT of ≈ 0.3. The high reliability and low energy use were achieved by: (a) development of an accurate bench-test-based simulation; (b) development of an intuitively tuned nominal trajectory based on simple locomotion models; and (c) offline design of a simple reflex-based (that is, event-driven discrete feed-forward) stabilizing controller. Further, once we replaced the intuitively tuned nominal trajectory with a trajectory found from numerical optimization, but still using event-based control, we could further reduce the TCOT to 0.19. At TCOT = 0.19, the robot’s total power of 11.5 W is used by sensors, processors and communications (45%), motor dissipation (≈34%) and positive mechanical work (≈21%). Ranger’s reliability and low energy use suggests that simplified implementation of offline trajectory optimization, stabilized by a low-bandwidth reflex-based controller, might lead to the energy-effective reliable walking of more complex robots.

Recently, parallel operation of dc-dc converters has been widely used in distributed power systems. In this paper, a control method to achieve parallel operation of three-phase bi-directional isolated interleaved dc-dc converters is discussed for the battery charging and discharging system which consists of the 32 battery charger/dischargers and two three-phase bi-directional isolated interleaved dc-dc converters. In the boost mode, the battery energy is delivered to the grid, whereas the grid energy is transferred to the battery in the buck mode operation. The average current sharing control method is employed to obtain an equal conducting of each phase current in the three-phase dc-dc converter. By using the proposed method, the imbalance factor is gratefully reduced from 8 percent to 1 percent. Two 2.5kW three-phase bi-directional dc-dc converter prototype have been built and the proposed method has been verified through experiments.

This paper proposes a power coordinated control strategy based on the state of battery charge and discharge to solve the real-time power distribution in the new energy power generation system and reduce energy loss. Taking the hybrid wave and photovoltaic power generation DC microgrid as the research object, high-pass filter control is used in the hybrid energy storage unit to achieve unbalanced power distribution; then adjust the super capacitor energy storage according to the battery charging and discharging state, and find the optimal power reference value through continuous loop iterations to improve the overall adjustment ability. Combining with the balance of supply and demand in the system, an improved DC bus signal DBS control method is further constructed, and the current control strategy of space vector modulation is used to realize the power control of each power generation source of the system, and suppress the fluctuation characteristics of waves and photovoltaic power generation, which causes the system to frequently switch working states. Simulation shows that this method effectively improves system reliability, keeps the bus voltage stable, and optimizes the charging and discharging capabilities of hybrid energy storage.

This paper's goal is to present a low cost, non-conventional solution for battery state of charge estimation and external electrical input presence/absence for a commercial mobile, handheld device whose battery state of charge control is critical. This solution is based on treating and filtering a time series in real-time software, using the battery pack characteristic discharge curve and time series statistical features. The time series is composed of data that is sampled embedded in hardware, communicating directly with the machine's BIOS. The system processes this data and outputs a value that indirectly relates to state of charge, needing further processing to insure accuracy. The data stream is treated in a process that directly relates the output time series with state of charge through a transfer function, effectively treating intermediary conversions as black boxes to simplify analysis and implementation. This process can also detect if an external source is connected/disconnected by exploiting pre-detected features in the time series. This approachadvantages are its low cost and simplicity, reducing hardware complexity and expenses; small dimensional footprint; mostly software-based; and centralization into the main hardware as low computational cost daemons, simplifying data consumption.

Rule-based near-optimal control strategy derived from global optimization results has the best real-time performance among current online optimal control strategies of the hybrid electric vehicle. However, the battery charge sustainability based on the rule-based near-optimal control strategy is not theoretically studied in current researches, which is important for robust control in complex driving conditions. In this paper, a deviation correction strategy based on linear quadratic regulator (LQR) is proposed for a power-split hybrid electric bus in order to sustain the battery’s state of charge (SOC). The LQR controller is designed according to an equivalent circuit model based on the state feedback control. Offline simulation is carried out to verify the proposed strategy under different driving cycles. Results show that, with the proposed strategy, the SOC can converge to a predefined value at the end of the optimization horizon.

This paper considers cases where a specific number of nodes in an ad hoc network broadcast video and audio streams over the entire network, and proposes Load and Battery Charge Oriented Flooding (LBF), which reduces degradation in delivery quality, lowers energy consumption, and prevents nodes from being interrupted due to the complete discharge of their batteries. It also describes an evaluation of the proposed method through network simulation, and confirms its effectiveness. © 2013 Wiley Periodicals, Inc. Electron Comm Jpn, 96(6): 57–66, 2013; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.11567