Search Results (54)

In applications where it is crucial that a battery is recharged from the partially discharged state in the minimum time, it is crucial to honor the technological constraints related to maximum safe battery terminal voltage and maximum continuous charging current prescribed by the battery cell manufacturer. To this end, this contribution outlines the design and comprehensive simulation analysis of an adaptive battery charging system relying on battery open-circuit voltage estimation in real time. A pseudo-random binary sequence test signal and model reference adaptive system are used for the estimation of lithium titanate battery cell electrical circuit model parameters, with the design methodology based on the Lyapunov stability criterion. The proposed adaptive charger is assessed against the conventional constant-current/constant-voltage charging system. The effectiveness of the real-time parameter estimator, along with both the adaptive and traditional charging systems for the lithium titanate battery cell, is validated through simulations and experiments on a dedicated battery test bench. Full article

The utilization of electric vehicles (EVs) has grown significantly and continuously in recent years, encouraging the creation of new implementation opportunities. The battery electric vehicle (BEV) charging system can be effectively used during peak load periods, for voltage regulation, and for the improvement of power system stability within the smart grid. It provides an efficient bidirectional interface for charging the battery from the grid and discharging the battery into the grid. These two operation modes are referred to as grid-to-vehicle (G2V) and vehicle-to-grid (V2G), respectively. The management of power flow in both directions is highly complex and sensitive, which requires employing a robust control scheme. In this paper, an Integral Fast Terminal Synergetic Control Scheme (IFTSC) is designed to control the BEV charger system through accurately tracking the required current and voltage in both G2V and V2G system modes. Moreover, the Black-Winged Kite Algorithm is introduced to select the optimal gains of the proposed IFTS control scheme. The system stability is checked using the Lyapunov stability method. Comprehensive simulations using MATLAB/Simulink are conducted to assess the safety and efficacy of the suggested optimal IFTSC in comparison with IFTSC, optimal integral synergetic, and conventional PID controllers. Furthermore, processor-in-the-loop (PIL) co-simulation is carried out for the studied system using the C2000 launchxl-f28379d digital signal processing (DSP) board to confirm the practicability and effectiveness of the proposed OIFTS. The analysis of the obtained quantitative comparison proves that the proposed optimal IFTSC provides higher control performance under several critical testing scenarios. Full article

Efficient and safe charging of lithium-ion batteries is essential for maximizing their lifespan and performance. This paper presents the design and implementation of a microcontroller-based Li-ion battery charger that employs real-time monitoring, adaptive charging strategies, and built-in safety mechanisms. The system integrates a CC/CV charging approach with automatic current regulation, overcharge protection, and reverse polarity detection. A current sensor module ensures continuous monitoring, while an LCD interface provides real-time feedback on charging parameters. Experimental validation was conducted using multiple Li-ion cells in various conditions, like new, aged, and deeply discharged, to evaluate charging behavior and safety under different scenarios. The system successfully regulated current and voltage, managed preconditioning for low-voltage cells, and transitioned smoothly between charging phases. A key contribution of this work is the development of a low-cost, microcontroller-based platform that enables flexible implementation and testing of diverse charging strategies. Its open-source architecture and modular design make it highly suitable for research, educational use, and experimental development in battery management systems. Future enhancements may include the integration of adaptive algorithms based on internal resistance and temperature, enabling smarter and more efficient charging. Full article

A prototype of a mobile electric charging station was developed to simulate the energy supply to a rural medical post. A 20 m² medical post module was built, divided into two rooms (medical staff room and patient room) and a heater, a freezer, a refrigerator, lights and a personal computer were added inside. The mobile electric charging station was made up of an array of 2.88 kW flexible photovoltaic panels, a 48 V and 19.2 kW·h LiFePO₄ battery bank, a charger inverter with a total capacity of 5 kW and a 4 kW electric generator. All of this equipment was placed in an all-terrain pickup truck. Temperature sensors and electrical sensors were installed to evaluate the performance of the prototype in charging and discharging scenarios. Results were obtained according to the operation over 10 months in the city of Arequipa, Peru. The results indicate an indefinite autonomy on clear days, the autonomy varying between 7 and 10 days for a climate with medium cloudiness, and with very cloudy conditions (i.e., with rain), the autonomy is 2 to 3 days. In circumstances of low solar irradiance, the generator had to supply the energy, thereby improving energy autonomy. Full article

The increasing spread of photovoltaic systems for private households (PVs) and electric vehicles (EVs) in order to reduce carbon emissions significantly impacts operation conditions in existing distribution networks. Variable and unpredictable PVs can stress distribution network operation, mainly manifested in voltage violations during the day. On the other hand, variable loads such as EV chargers which have battery storage in their configuration have the ability of storying a surplus energy and, if it is necessary, support a distribution network with energy, commonly known as vehicle-to-grid concept (V2G), to help voltage stability network enhancement. This paper proposes an optimal power flow (OPF)-based model for EV charging to minimize power exchange between the superior-10 kV grid and the observed distribution feeder. The optimization procedure is realized using the co-simulation approach that connects power flow analysis software and optimization method. Three different scenarios are observed and analysed. The first scenario is referred to as a base case without optimization. The second and third scenarios include optimal EV charging and discharging patterns under different constraints. To test the optimization model, a 90-bus unbalanced distribution feeder modelled based on real-life examples is used. The obtained results suggest that this optimization model does not only significantly reduce the power exchange between an external network and the distribution feeder but also improves voltage stability and demand curve in the distribution feeder. Full article

Solar energy is considered the major source of clean and ubiquitous renewable energy available on various scales in electric grids. In addition, solar energy is harnessed in various electronic devices to charge the batteries and power electronic equipment. Due to its ubiquitous nature, the corresponding market for solar-charged small-scale batteries is growing fast. The most important part to make the technology feasible is a portable battery charger and the associated controllers to automate battery charging. The charger should consider the case of charging to be convenient for the user and minimize battery degradation. However, the issue of slow charging and premature battery life loss plagues current industry standards or innovative battery technologies. In this paper, a new pulse charging technique is proposed that obviates battery deterioration and minimizes the overall charging loss. The solar-powered battery charger is prototyped and executed as a practical, versatile, and compact photovoltaic charge controller at cut rates. With the aid of sensor fusion, the charge controller is disconnected and reconnects the battery during battery overcharging and deep discharging conditions using sensors with relays. The laboratory model is tested using a less expensive PV panel, battery, and digital signal processor (DSP) controller. The charging behavior of the solar-powered PWM charge controller is studied compared with that of the constant voltage–constant current (CV–CC) method. The proposed method is pertinent for minimizing energy issues in impoverished places at a reasonable price. Full article

To solve the problems of large switching losses and the need for large-capacity electrolytic capacitances in three-phase DC/AC on-board chargers for vehicle-to-grid (V2G) applications, this paper proposes a single-stage bidirectional high-frequency isolated converter that eliminates the need for large-capacity capacitances. Combined with the proposed modulation scheme, it can theoretically reduce the switching loss by about two-thirds with the three-phase converter compared with the conventional modulation scheme, improving the converter’s operating efficiency and power density. Firstly, based on the characteristics of the proposed topology, a hybrid modulation scheme is proposed, which combines a phase-shift modulation scheme based on double modulation waves and a sawtooth carrier with a 1/3 modulation scheme, and the theoretical feasibility of the hybrid modulation scheme is verified using a mathematical modeling equation. Secondly, this paper provides a detailed analysis of the four operating modes of the two full-bridge circuits and the commutation process of the three-phase converter within 1/6 of the fundamental frequency cycle (P₁ modulation interval). Then, the control strategy is given for the constant-current and constant-voltage charging and constant-current discharging for electric vehicle batteries. Finally, simulation results verify the correctness of the proposed topology and modulation scheme in vehicle–grid interaction. Full article

Electric vehicles (EVs) are crucial in mitigating global emissions by replacing internal combustion engines. The capacity of EV batteries, coupled with their charging infrastructure, offers the added advantage of supplying flexible demand capacity and providing demand response benefits to the power grid, which is essential as overall demand increases. EVs ready for vehicle-to-everything (V2X) applications and chargers that support them enhance this flexibility by allowing for varied storage applications. However, to fully harness these benefits, it is vital to consider EV drivers’ charging habits and optimize the charging and discharging controls to minimize battery life impact. This study examines various V2X applications in North America and their effects on battery longevity, considering EV charging patterns. Additionally, it investigates advanced aging-aware optimization algorithms for managing bidirectional charging. Full article

Low-temperature preheating, fast charging, and vehicle-to-grid (V2G) capabilities are important factors for the further development of electric vehicles (EVs). However, for conventional two-stage chargers, the EV charging/discharging instructions and grid instructions cannot be addressed simultaneously for specific requirements, pulse heating and variable-current charging can cause high-frequency power fluctuations at the grid side. Therefore, it is necessary to design a bidirectional grid-friendly charger for EVs operated under pulse-current heating and variable-current charging. The DC bus, which serves as the medium connecting the bidirectional DC–DC and bidirectional DC–AC, typically employs capacitors. This paper analyzes the reasons why the use of capacitors in the DC bus cannot satisfy the grid and EV requirements, and it proposes a new DC bus configuration that utilizes energy storage batteries instead of capacitors. Due to the voltage-source characteristics of the energy storage batteries, EV instructions and grid instructions can be flexibly and smoothly scheduled by using phase-shift control and adaptive virtual synchronous generator (VSG) control, respectively. In addition, the stability of the control strategy is demonstrated using small signal modeling. Finally, typical operating conditions (such as EV pulse preheating, fast charging with variable current, and grid peak shaving and valley filling) are selected for validation. The results show that in the proposed charger, the grid scheduling instructions and EV charging/discharging instructions do not interfere with each other, and different commands between EVs also do not interfere with each other under a charging pile with dual guns. Without affecting the requirements of EVs, the grid can change the proportion of energy supply based on actual scenarios and can also obtain energy from either EVs or energy storage batteries. For the novel charger, the pulse modulation time for EVs consistently achieves a steady state within 0.1 s; thus, the pulse modulation speed is as much as two times faster than that of conventional chargers with identical parameters. Full article

A single-phase bidirectional DC/DC battery charger with a P&O MPPT current control strategy for a standalone energy management system has been integrated with an interleaved switched capacitor DC/AC inverter with an RMS feedback phase-shifted unipolar sinusoidal PWM control strategy. In the published literature, P&O MPPT control is used to drive a boost converter connected in parallel to a battery charger; this modified strategy combines a P&O MPPT algorithm with current control to drive an interleaving buck-boost battery charger. This battery charger circuit is connected in parallel to a closed loop controlled interleaved inverter that feeds the AC home load. MATLAB/Simulink based simulation circuit was developed and used to validate the successful integration of the interleaved battery charger with the global system. To do this, the system is tested with varying input conditions of irradiance and temperature. The system’s response to these variable inputs is monitored and analysed. The simulation results show the proposed method is effective for standalone battery-based PV systems. The system provides a more efficient and faster response compared with both an interleaved and non-interleaved voltage-controlled battery charger circuit that is also integrated with the global system. This battery charger control strategy is also shown to protect the battery from over-charging as well as discharging below 25%, which can improve and protect the long-term battery performance. Compared with novel industry approaches, the proposed system is simpler by nature due to the reduced number of conversions and therefore a reduced number of components which provides economic advantages. Full article

Raising the electrification ratio to 100% is still a formidable challenge in Indonesia, especially in the remote areas of the eastern part of the archipelago. A DC microgrid system is one of the most viable solutions to increase the electricity supply in remote areas, taking advantage of various renewable energy sources that are located near the rural load centers. A DC–DC power converter for a rural DC microgrid system needs to have a high voltage gain to facilitate the power conversion from low-voltage PV output to a high-voltage DC microgrid bus, a very low input ripple current to help maintain the PV or battery lifetime, and be highly modular for ease of transport and assembly. Many topologies have been proposed to obtain high voltage gain, very low ripple current, and modularity. However, they usually use either bulky and lossy magnetic components, are sensitive to component parameter variance and need special voltage-balancing techniques, or have different component ratings for their multilevel configuration which weakens the modularity aspect. This paper proposes a new modular multilevel DC–DC converter that is very suitable for rural DC microgrid applications based on a modified buck–boost topology. The proposed converter is easily stackable to achieve high voltage gain and does not require any voltage balancing techniques, thus enhancing the modularity characteristics and simplifying its control method. Moreover, the ripple current can be reduced by employing a multiphase configuration. This converter can also facilitate bidirectional power flow to serve as a battery charger/discharger. A comprehensive analysis of voltage gain and ripple current are presented to explain the inner workings of this converter. Finally, the performance of this converter is verified through simulation and experiment, showing the converter’s modularity, bidirectional power capability, and potential to achieve voltage gain and ripple-current requirements of the DC microgrid system. Full article

This study discusses the resonance characteristics of the LLC resonant half-bridge converter and smart battery charging for the fast charging of personal mobility devices (e.g., electric kickboards, segways, hoverboards, electric bicycles, and electric motorcycles), whose use is rapidly increasing. Through the analysis of resonance characteristics, this study aims to validate that f_S > f₀ is the most appropriate correlation in the relationship between resonant frequency (f₀) and switching frequency (f_S) that is suitable for the rapid charging of batteries of personal mobility devices. Additionally, the proposed half-bridge converter does not charge the battery from discharge or misconnection based on the detection of the battery voltage for the batteries of personal mobility devices. Therefore, the proposed converter suggests a charging system based on battery state detection that stably performs rapid charging of the batteries of personal mobility devices by equalizing the battery voltage and the charger voltage through a pre-charge operation. Full article

This paper presents a 250 kHz bidirectional battery charger circuit using a GaN HEMT. The charger is subjected to a high-/low-side constant voltage at 200 V/20 V. The charger circuit is a hybrid of the LLC and flyback circuit topologies. Both the power output analysis and efficiency control of this circuit are simplified when the magnetization current is minimized using the low-resistance GaN HEMT. The switching frequency is controlled to match the series resonance in a way that is analogous to conventional LLC circuit controls, while the duty ratio that determines the power output and the dead time, which determines the zero voltage switching, is controlled in an analogous manner to the flyback circuit control. The charging and discharging modes were altered by applying a double-throw relay that changes the transformer turn ratio, which is different from conventional LLC designs using the switching frequency adjustment. A nominal turn ratio with N_p = 35 and N_s = 3.5 for a 200 V/20 V converter can only produce an internal series resonance with no current flowing in any charging direction. The proposed circuit using a transformer with multiple windings (N_p = 35, N_s,F = 4, and N_s,R = 3) was fabricated to deliver 125 W output power from the power grid battery to the vehicle battery in the forward (charging) mode and 90 W in the reverse (discharging) mode. The conversion efficiency was calculated to be as high as 97% in the forward mode and 95% in the reverse mode. The high conversion efficiency is due to the characteristics of the GaN HEMT, including low resistive and switching losses. The equations derived in this paper associate these losses with the series resonant frequency and power conversion rate, which highlight the advantages of using a GaN HEMT in this CLLC design. Full article

Fluctuant irradiance conditions constitute a challenge in front of a proper battery charging process, when originated from a PhotoVoltaic Array (PVA). The behavior of the PVA under such conditions (i.e., reflected by a disturbed PV characteristic curve) increases the complexity of the total available power’s extraction process. This inconvenient fact yields eventually to a decreased overall efficiency of PV systems, especially with the presence of imprecise power-electronics involved circuits. Accordingly, the purpose of this paper is to design a complete battery solar charger, with Maximum Power Point Tracking ability, emerged from a PVA of 1.918 kWp, arranged in Series-Parallel topology. The targeted battery is of Lithium-Ion (Li-I) type, with 24 VDC operating voltage and 150 Ah rated current. The design began by configuring an interleaved synchronous DC-DC converter to produce a desired voltage level, with low inductor ripple current and low output ripple voltage. The DC-DC converter is in turns condemned by a modified Perturb and Observe (P&O) algorithm, to ensure efficient maximum power tracking. Progressively, the design encountered a layout of the bi-directional DC-DC converter to ensure safe current charging values for the battery. Under the same manner, the role of the bi-directional converter was to plug the battery out of the system, in case when the Depth of Discharge (DoD) is below 25%, thus sustaining the life span of the battery. The entire setup of the proposed sub-systems then leads to the relatively fastest, safest, and most reliable battery charging process. Results show an effectiveness (in terms of PV power tracking) ranging from 87% to 100% under four swiftly changing irradiance conditions. Moreover, this paper suggested the design’s future industrialization process, leading to an effective PV solar charger prototype. Full article

The growing use of DC/DC power converters has resulted in the requirement that their complex controllers be cheaper and smaller, thus using cost-effective implementations. For this purpose, it is necessary to decrease the computational burden in controller implementation to minimize the hardware requirements. This manuscript presents two methods for tuning an adaptive linear–quadratic–Gaussian voltage controller for a battery charger/discharger, implemented with a Sepic/Zeta converter, to work at any operating point. The first method is based on a lookup table to select, using the nearest method, both the state feedback vector and the observer gain vector, solving the Riccati’s differential equation offline for each practical operating point. The second method defines a polynomial function for each controller element that is based on the previous data corresponding to the system operating points. The adaptability of the two controllers to fixed voltage regulation and reference tracking was validated using simulations and experimental tests. The overshoot and settling time results were lower than 11% and 3.7 ms, which are in the same orders of magnitude of a control approach in which the equations are solved online. Likewise, three indices were evaluated: central processing unit capacity, cost, and performance. This evaluation confirms that the controller based on polynomial interpolation is the best option of the two examined methods due to the satisfactory balance between dynamic performance and cost. Despite the advantages of the controllers in being based on a lookup table and polynomial interpolation, the adaptive linear–quadratic–Gaussian has the benefit of not requiring an offline training campaign; however, the cost saving obtained with the lookup table controllers and polynomial interpolation controllers, due to the possible implementation on small-size microcontrollers with development tool simple and easy maintenance, will surely be desirable for a large number of deployed units, ensuring that those solutions are highly cost-effective. Full article