Search

This paper proposes a new hybrid control strategy to solve the problem of bidirectional wide voltage range regulation in CLLC converters. On the (LLC) side (G2V direction), the SSSA control method is employed for voltage boost, combined with bus voltage and burst control to achieve wide voltage regulation. On the (C) side (V2G direction), the SSSA and full/half‐bridge mode switching control are used to achieve V2G direction wide voltage regulation. This hybrid control strategy also enables high conversion efficiency in both directions without the need for additional components to reduce the converter power density. This is particularly suitable for OBC applications with strict requirements for converter volume and weight. A detailed analysis with mathematical derivation, hybrid control strategy, and converter operation principles is introduced in this paper. The following subchapters supplement the converter voltage gain, soft switching implementation conditions, and design considerations. Finally, the feasibility of the proposed control strategy was verified through an experimental prototype with an input voltage ranging from 340 to 430 V to an output voltage ranging from 225 to 450 V and bidirectional rated power of 6.6/3.3 kW. This prototype achieved a maximum conversion efficiency of 97.7% in the G2V direction and 97.1% in the V2G direction. [ABSTRACT FROM AUTHOR]

The rising Greenhouse Gas (GHG) emissions stemming from the extensive use of automobiles across the globe represent a critical environmental challenge, contributing significantly to phenomena such as global warming and the deterioration of air quality. To address these challenges, there is a critical need for research and development in electric vehicles (EVs) and their associated charging infrastructure, including off-board and on-board chargers (OBCs). This paper aims to bridge the gaps in existing review literature by offering a comprehensive review of both integrated and non-integrated OBCs for EVs, based on the authors' knowledge at the time of writing. The paper begins by outlining trends in the EV market, including voltage levels, power ratings, and relevant standards. It then provides a detailed analysis of two-level and multi-level power converter topologies, covering AC-DC power factor correction (PFC) and isolated DC-DC topologies. Subsequently, it discusses single-stage and two-stage non-integrated OBC solutions. Additionally, various categories of integrated OBCs (iOBCs) are explored, accompanied by relevant examples. The paper also includes comparison tables containing technical specifications and key characteristics for reference and analysis. [ABSTRACT FROM AUTHOR]

To protect the battery, radio energy transmission charging typically uses constant current (CC) charging before switching to constant voltage (CV) charging to enhance battery durability. This paper proposes adding an auxiliary clamp coil to the original circuit topology. The IPT battery charger designed with the auxiliary clamp coil can achieve both constant current (CC) and constant voltage (CV) outputs. The mutual inductance between the auxiliary clamp coil and the primary side coil greatly influences the output performance of the entire IPT system, so the auxiliary clamp coil should not be too large. To solve this problem, an S-S-PS circuit with secondary compensation topology in the secondary coil is proposed. This circuit topology reduces the size of the auxiliary clamp coil, allowing it to be placed in an optimal position. When the constant voltage output critical position is reached, the IPT system can still automatically, continuously, and smoothly switch between CC and CV modes. Consequently, this approach avoids increased cost consumption associated with detecting CC-CV switching thresholds, adding wireless transmission communication modules, real-time control of the power transmitter, and active protection of the circuit during constant current charging. Finally, a 48 V/2.5 A prototype was built to verify that the IPT system has CC-CV conversion functionality. [ABSTRACT FROM AUTHOR]

In two-stage electric vehicle (EV) battery chargers, ac-dc conversion stage contributes significantly in determining the power quality. At this stage, multilevel rectifiers (MLRs) featuring switches with lower voltage rating and better input voltage waveform quality can be adopted. However, balancing capacitor voltage in MLR is an important challenge. In this paper, a single-phase five-level power factor correction (PFC) rectifier with self-balancing capacitor is implemented for EV battery charging. The complimentary switching scheme adopted for rectifier reduces number of gate driver circuits and ensures capacitor voltage balancing. The rectifier shows added benefit of reduced voltage stress across switches and not requiring an external filter at the dc side as the load is parallelly connected with one of the capacitors. The operating principle, control strategy, modulation technique and design features of the implemented five-level rectifier is discussed in detail. The implemented control scheme enhances rectifier performance by establishing precise output voltage regulation during load fluctuations while maintaining unity power factor at input side. The five-level rectifier is validated experimentally and compared with other existing multilevel and non-multilevel rectifier topologies. The peak efficiency of 93.8% is achieved at 2 kW of output power. [ABSTRACT FROM AUTHOR]

Modular multilevel converters with non-sinusoidal ac voltage output can reduce cost and volume in medium-voltage-connected electric vehicle battery charging applications. The use of full-bridge submodules in such converters enables single-stage ac/ac voltage conversion, allowing a medium-voltage grid to be directly connected to a medium-frequency isolation transformer. The application of a square wave voltage at the medium-frequency transformer's single-phase port enhances the converter's efficiency and power density in comparison to a sinusoidal voltage. This paper presents the analysis and modelling of a modular multilevel converter, comparing its operation with sinusoidal and square wave output voltages. A single control scheme for both output voltage waveforms is proposed for the three-phase and single-phase ac currents, circulating currents, and the energy stored in the submodule capacitors. The control strategy of the three-phase and single-phase port currents is verified through simulation and experiments using a scaled-down prototype, thereby validating its suitability for high-power bidirectional battery chargers. [ABSTRACT FROM AUTHOR]

This paper offers a unique and novel approach for electric vehicle battery charging by incorporating a solar PV-integrated dc to dc boost converter. Traditional power electronic converters used in such applications often face limitations including low voltage gain, low conversion efficiency, high ripple content, and inadequate controller performance. To overcome these challenges, the study introduces the Improved A-Source Boost Converter (IASBC) along with an interval type-2 fuzzy logic controller (IT2FLC) and MPPT technique for continuous switching with optimal design. The IASBC, equipped with a coupled inductor, enhances load side performance by achieving high conversion efficiency and voltage gain while minimizing the impact of network parasitic. Additionally, the proposed controller technique effectively reduces output side dc ripple content through gain parameter optimization. The system is optimized for charging a 48 V rechargeable battery within a solar photovoltaic voltage range of 25–75 V DC. Extensive simulations using MATLAB validate the efficacy of the proposed approach. The software analysis reveals an efficiency of 90.82% in the open-loop system and 98.57% in the closed-loop system, while the hardware system achieves an efficiency of approximately 98.55%. Furthermore, a 100 W experimental design is developed and compared with the simulation results, providing validation for the technical significance of the suggested converter. This novel approach not only addresses the limitations of conventional converters but also offers improved performance in terms of efficiency, voltage gain, and ripple content. The proposed system holds promise for efficient electric vehicle battery charging and can contribute to the advancement of sustainable energy solutions. [ABSTRACT FROM AUTHOR]

The application of electrochemical cells as a source unit of electrical energy is rapidly growing—used in electric vehicles and other electric mobility devices, as well as in energy supply systems—as energy storage, often together with renewable energy sources. The key element of such systems is the power electronic converter used for DC energy storage and AC grid interfacing. It should be bidirectional to charge and discharge the battery when it is necessary. Two-stage battery interface converters are the most common; their DC-DC stage controls the battery current and adjusts voltage, but the DC-AC stage (inverter or frontend) controls the current in the grid. The use of unfolding inverters in two-stage battery interfaces can have some advantages. In this case, the DC-DC converter produces half-sinewave pulsating voltages and currents, but the unfolding circuit changes the polarity of the voltages and currents and produces no switching losses. Another trend of modern power electronics is the principle of partial power processing. In this case, power electronic converters deal only with a part of the total power; therefore, losses in such converters are reduced. This paper considers combining unfolding frontends with partial power DC-DC converters that enable the further reduction in losses. In this paper, it is shown that such implementation of the partial power conversion principle in semi-DC-AC systems is really possible based on the real-time matching of the voltage of the partial-power DC-DC converter, battery voltage (which depends on its state of charge) and the rectified instantaneous voltage of the AC grid. [ABSTRACT FROM AUTHOR]

There is a global trend to reduce emissions from cars through the adoption of other alternatives, such as electric vehicles (EVs). The increasing popularity of EVs has led to a growing demand for electric vehicle chargers. EV chargers are essential for charging the batteries of EVs. Since the EV charger stays connected to the grid for long periods of time to charge the EV battery, it must be able to handle disturbances in the power grid. The goal of this paper is to present an overview of the impact of grid events on EV battery chargers. As well as the impact of grid unbalances on EV chargers, this paper also provides an overview of the impact of grid faults on other, similar power electronics interfaced resources such as PV and energy storage systems. [ABSTRACT FROM AUTHOR]

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 Np = 35 and Ns = 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 (Np = 35, Ns,F = 4, and Ns,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. [ABSTRACT FROM AUTHOR]

Due to their significant performance, Phase-Shifted Full-Bridge Converters (PSFBCs) have gained widespread adoption in medium- and high-power applications. The performance of a PSFBC is greatly influenced by its magnetic components, namely the transformer and resonance inductor. To address these challenges, this paper proposes a parameter optimization of magnetic components for PSFBCs, specifically the transformer turns ratio and resonance inductor value, to enhance conversion efficiency and minimize operational loss. A digital twin of PSFBCs enabling a more accurate loss estimation is proposed to achieve this objective. The proposed loss estimation method precisely calculates the effective and circulation intervals and the corresponding current points of the primary-side transformer current, resulting in improved accuracy. By leveraging the digital twin, the effects of transformer turns ratio and resonant inductor value on the conversion efficiency of a PSFBC can be efficiently simulated. This facilitates the parameter optimization of magnetic components, thereby minimizing operational losses across different application scenarios. This paper also designs and implements a PSFBC prototype with a rated input voltage of 380 V, output voltage of 24 V, and output current of 20 A. The experimental results show the influences of transformer turns ratio and resonant inductor value on the PSFBC and validate the proposed digital twin. The proposed parameter optimization of magnetic components is further evaluated across two application scenarios with varying utilization rates. The simulation results indicate a reduction of approximately 14% in operational loss per hour after applying the parameter optimization of magnetic components for the PSFBC used as a battery charger. The results demonstrate the effectiveness and practicality of the proposed digital twin in designing PSFBCs. [ABSTRACT FROM AUTHOR]

The paper deals with a grid-connected single-phase battery charger integrated with photovoltaic generators (PVGs). The circuit topology consists of a multilevel architecture based on a Cascaded H-Bridge (CHB) rectifier. Its main task is to charge the batteries, primarily from the PVGs, by also assuring to keep their state-of-charge (SOC) balanced. Nevertheless, when the battery SOC overcomes a predefined upper limit, beyond which the charging process could be interrupted, the available PV power can no longer be transferred to the batteries. Therefore, to avoid an undesired curtailment of PV power production, this latter can be supplied to the grid by inverting the system operation. The paper shows how to achieve this result by implementing a dedicated control action based on a multi-step procedure. Numerical investigations are carried out on a 19-level CHB converter implemented in the PLECS environment to validate the feasibility and effectiveness of the proposed control technique. [ABSTRACT FROM AUTHOR]

For meeting the actual demand of constant current (CC) and constant voltage (CV) in lithium-ion battery-charging process and improve the flexibility and safety of charging, this paper proposes a family of hybrid inductive power transfer (IPT) topologies that can realise CC and CV output and are not limited by the parameters of coils. Starting from a single existing topology with configurable CC or CV output, which can achieve zero-voltage switching (ZVS), load-independent and approximately zero reactive power, and the missing configurable CC or CV output is obtained by circuit transformation through cascaded T-type network. Then, the cascaded T-type network is switched by mode switches, so as to derive a family of hybrid IPT topologies suitable for lithium-ion battery wireless charging. In order to reduce the number of devices in the compensation network, the T-type network can be integrated with the existing compensation networks. Hence, this paper also proposes some hybrid IPT battery chargers and their design ideas. The control logic of mode switches and the sensitivity of compensation parameters are also discussed. Ultimately, a hybrid IPT battery charger based on S-S and S-LCC compensation networks is developed to test the correctness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Summary: This paper describes a quasi‐two‐switch buck‐boost power factor correction (PFC) converter for use in on‐board battery chargers to create a variable output voltage that is less than or greater than the peak input voltage. A two‐stage converter links the input grid power to the battery pack both in battery‐operated electric cars (BEVs) and plug‐in hybrid electric vehicles (PHEVs), with battery pack voltages ranging from 100 to 500 V depending on vehicle size and capacity. A universal charger that can manage such a wide range of battery pack voltages is appropriate for all vehicle designs. This requirement is met by supplying a changeable DC link voltage at the input of the DC/DC converter, which is a major obstacle in battery chargers when it comes to achieving universal output voltages. The major contribution of this research is the analysis and design of a dual‐control technique for a cascaded buck‐boost converter suited for a power factor correction (PFC) rectifier. The control loop is designed to allow a seamless transition from buck‐boost operation while putting less stress on the devices. The converter's power loss and small‐signal model are also investigated. From an economic standpoint, this concept allows the automobile industry to manufacture a single power converter, which is flexible and capable of charging numerous vehicle variants. Results have been verified both with a PSIM (11.0) simulation model and an experimental setup for a 1‐kW PFC converter suitable for universal input voltages of 85–265 Vrms and broad output voltages. [ABSTRACT FROM AUTHOR]

This paper proposes an interleaved multilevel converter (MLC)-based charger with power rating 2.8 kW to charge on-board battery of electric vehicle (EV). It comprises two stages: (1) an interleaved multilevel ac–dc converter; and (2) an LLC-resonant dc–dc converter. The interleaved approach efficiently maintains the optimum power level. The switching scheme implemented for MLC maintains the source current sinusoidal, supports unity power factor (UPF) and has the capability to balance the capacitor voltage. The MLC maintains UPF and balances capacitor voltage without any auxiliary circuit. In addition, MLC provides lower voltage stress and reduced total harmonic distortion (THD), therefore, making it a better choice for ac–dc conversion stage in battery charging application. The dc–dc converter furnishes regulated and wide output voltage range for on-board charging system. The principle of operation, modulation technique and control strategy for both the converters are analysed. Following theoretical analysis, laboratory experiments were conducted to validate the implemented approach. The results signify that for output voltage range of 24−72 V, UPF is maintained at input, lower stress across switches and capacitor voltage is balanced. The performance of MLC is satisfactory as it attains a peak efficiency of 97% with THD of 2.07%. [ABSTRACT FROM AUTHOR]

Commonly used lithium‐ion battery on‐board charger (OBC) for electric vehicles (EVs) needs a wide output voltage range, but the traditional LLC converter is hard to meet the need under the condition of high efficiency and high power density. In this paper, a resonant converter with hybrid modulation is proposed. The converter has a relatively simple topology and control method. Compared with the traditional LLC topology, only two diodes are replaced by MOSFETs on the secondary side of the transformer, and no auxiliary components are added. The primary‐side switches adopt PFM) and the secondary‐side switches adopt short‐circuit control in the proposed converter, which can realize a wide output voltage range, in a narrow switching frequency range with excellent soft‐switching performance. The proposed converter can effectively reduce the resonant current and the volume of transformer core and achieve energy delivery with high power density and high efficiency. The operation principles, voltage gain, and soft‐switching conditions of the converter are analyzed in this paper. Finally, a 3.3‐kW SiC‐based prototype with 400‐V input and 250‐ to 430‐V output is built to verify the feasibility and validity of the proposed converter. [ABSTRACT FROM AUTHOR]

The concept of the integrated onboard battery charger (IOBC) provides electric vehicles (EVs) with access to the integration of the drivetrain and the charger. In this paper, an IOBC based on a six-phase drive is studied. In the charging mode, the IOBC is equivalent to a paralleled three-phase voltage source rectifier (PTP-VSR) with common ac and dc sides. Such operation leads to a zero-sequence circulating current (ZSCC), which causes current waveform distortion and the resultant power loss. This paper proposes a novel ZSCC elimination strategy, which is in principle tied to finite control set model predictive control (FCS-MPC). By modifying the control set (CS), the ZSCC can be naturally circumvented without increasing the complexity of the control system. Furthermore, an enhanced phase-locked loop (EPLL) based on the second-order generalized integrator (SOGI) is proposed, by which, only sampling a line voltage is required. Finally, the effectiveness of the proposed strategy and EPLL are experimentally validated. [ABSTRACT FROM AUTHOR]

In this paper, a novel bidirectional multi-input energy harvesting converter (MIEC) for portable device charger is presented. Switches that are separately regulated using different duty ratios are used in the design of such an MIEC power converter. The peak power of the photovoltaic sources may be tracked using such duty ratios, and the battery power can also be managed. The switch with two directions is also a part of this converter. If necessary, the battery can be charged via a USB charger but it is also capable of supplying power to the portable charging devices using sun and vibration harvesting. A battery receives the remaining energy for recharging while the charging current level can be checked. The entire system built using the MATLAB/SIMULINK environment, performances are monitored by the simulation results and validated experimentally. [ABSTRACT FROM AUTHOR]

Recently, research on personal mobility devices (PMDs) such as electric motorcycles, electric bikes, electric scooters, and electric wheelchairs has been globally proceeded. However, PMDs have a disadvantage since the required battery voltage is different depending on the type of PMD. Therefore, to charge the battery of a PMD, an individual battery charger should be used depending on type of PMD which reduces industrial usability and availability of PMDs. To solve this problem, a battery charger capable of responding to various battery voltages is required. In this paper, the hardware-simulator development of a battery charger that can respond to the various battery voltages of PMDs is proposed, and it consists of a boost converter, a half-bridge series resonant converter, and a buck converter. Additionally, this paper presents a control strategy for use in the proposed hardware simulator. The effectiveness of the proposed hardware simulator and its control strategy are verified by experimental results. [ABSTRACT FROM AUTHOR]

This paper deals with an integrated charger of battery used in electric vehicles having a propulsion system equipped with an asymmetrical six-phase induction machine drive. Proposed charging system consists of a modified DC–DC (buck-boost) converter tropology, which is capable to charge the battery during plug-in and regenerative operation, and suitable to drive the propulsion system. Both step-up and step-down voltage regulation capability of the proposed tropology converter make it suitable to select a wide voltage range of battery with an adequate, but simple control in different operating modes (i.e., plug-in, regenerative and propulsion). Comparatively, proposed converter tropology uses a reduced number of components resulting in its smaller size, weight and cost. Furthermore, the propulsion system using multiphase (six-phase) induction machine drive also results in an overall improved performance of proposed system due to the implementation of efficient indirect field-oriented control. Complete system is developed on MATLAB/Simulink platform. Practical suitability, applicability and validity of control schemes of the proposed DC–DC converter on rectifier side and motor drive side converter in propulsion system have been tested on STM32F407G board employed during processor-in-loop simulation. Data transfer at high baud rate was achieved through externally connected USB-USART converter, i.e., FT32RL board between the target and host. [ABSTRACT FROM AUTHOR]

A power factor correction circuit plays a significant role in AC–DC conversion stage of electric vehicle (EV) battery chargers. Traditionally, two-level rectifiers are used at this stage, which suffers from increased voltage stress across its switches, resulting in poor power quality. Multilevel rectifiers provide lower voltage stress while maintaining high waveform quality and are viewed as a promising alternative for the ac–dc conversion stage. As a result, a five-level rectifier capable of achieving unity power factor with a self-balanced capacitor has been implemented in this paper. The rectifier has the advantage of reduced voltage stress across the switches. As the load remains in parallel with the output capacitor, the output filter capacitor is not required. The operating principle, modulation technique, closed-loop operation, and design features are discussed in detail. To achieve the regulated onboard EV battery charging, the five-level rectifier is integrated with a phase shift full bridge dc–dc converter. The entire system was mathematically modelled, simulated in MATLAB, and experimentally validated. A comparison of the implemented five-level rectifier with other topologies has been performed in order to determine its benefits and suitability for EV battery charging application. [ABSTRACT FROM AUTHOR]

Summary: As battery electric vehicles (BEVs), plug‐in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs) gain popularity among the consumers, current research initiatives are targeted at developing battery charger structures that can exploit utility power to charge vehicle batteries and thus less dependent on fuel usage. This paper reviews the state of the art and implementation of battery charger structures, charger power levels, and the evolution of publications on electric vehicles in the digital libraries and Espacenet patent base. Charger systems addressed are categorized as a structure with a non‐isolated alternating current (AC)–direct current (DC) stage, structure with an isolated AC–DC stage, and structure with two non‐isolated stages. Advantages and disadvantages of each conductive battery charging structure have been discussed due to weight, volume, cost, necessary equipment, the complexity of topologies, and other factors. In addition, both off‐board and on‐board charger systems with unidirectional or bidirectional power flow are presented. Several electronic converters for power‐level chargers are being developed to allow plug‐in vehicles to be capable of vehicle to grid (V2G), where they can function as distributed resources and power can be returned to the grid. [ABSTRACT FROM AUTHOR]

This paper proposes a wireless battery charger topology for electric vehicle (EV) application that can be installed in public charging infrastructure as well as in home premises. The proposed topology can maintain constant current as well as constant voltage at the battery terminal and simultaneously can maintain near unity power factor at the input side using power factor correction (PFC) operation and thus satisfy all the criteria of a standard EV charger. The heart of the wireless power transfer (WPT) scheme is a high-frequency (HF) inverter. In this work, a class EF2 inverter is used to generate HF AC in such a way that it can deliver power with variable loading condition while maintaining constant current (CC) or constant voltage (CV) according to the requirement of CC-CV charging profile. To supply power to this EF2 inverter, an AC-DC front-end converter (stage-1) is integrated with the charger. The stage-1 is operated as a constant voltage source to the EF2 inverter for CC mode and constant current source for CV mode operation. CC-CV at the battery end and PFC at the input end are achieved only by controlling the gate pulse of stage-1. The WPT coils are first simulated using Ansys Maxwell package, and the complete charger is simulated with PSIM simulation software. A scaled-down 200 W laboratory prototype of the proposed charger is developed and tested with a resistive load to validate the idea. The wireless power transfer is achieved for a maximum distance of 12 cm between the transmitting and receiving coil. Finally, the charger is tested to charge both 12 V and 24 V battery packs and the CC-CV charging profile is presented for the 24 V, 30 Ah battery pack. [ABSTRACT FROM AUTHOR]

Multiple battery charging systems can be configured with various combinations of ac‐dc and dc‐dc converters. This paper reviews the reliability and economy of three representative configurations of multi‐battery charging systems. Existing PSA (part stress analysis) can analyse the failure rate considering the environmental factors for the type of parts, the number of parts, the connection state of parts and the voltage and current stress of parts. However, since it does not reflect the system's operating characteristics, the Fault‐tree analysis (FTA) method based on the fault tree is used. Still, it cannot be analysed considering the operational risk of the converter according to various load conditions. Therefore, in this study, by defining a failure according to the minimum and maximum load of the multiple battery charging systems and designing a separate fault tree, the converter operation characteristics were considered by reflecting the number of battery charges, the characteristics according to SOC (state of charge) and the redundancy effect that appears when cyclic charging is applied. Through the new enhanced FTA method, the multiple battery charging systems (Type 1) to which sequential charging is applied are quantitatively proven advantageous in terms of reliability and economy. [ABSTRACT FROM AUTHOR]

This paper proposes a current-controlled hybrid power filter (CCHPF) to compensate source current harmonics produced by battery charger. Current harmonics are compensated by the voltage- and current-controlled active power filter, whereas in the proposed system, current-controlled hybrid power filter is used. CCHPF overcomes the limitation of voltage-controlled harmonic compensator, conventional proportional integral controller and the passive filter which has high power loss and which may deteriorate the system frequency with high harmonic attenuation. In the proposed control system, the super twisting sliding mode algorithm (STSMA) is used with a modified form of active power theory and cognitive emotional controller to compute the three-phase compensating current reference and the DC link current regulation. The compensated reference signal obtained by sliding mode controller is used to generate switching pulses to current-controlled active power filter (CCAPF) switches. The significant contribution of the proposed system includes the development of CCHPF and its control strategy based on PI- and emotional controller-tuned STSMA to reduce the harmonic distortion of the source current used in electric vehicle charging. The passive power filter is designed to eliminate fifth-order harmonic current. A major advantage of the super twisting sliding mode control algorithm is its adaptability and robustness, which will result in improved reference current tracking without causing chattering. CCHPF is widely used for compensating harmonics generated by electric vehicle battery chargers, UPS systems and industrial loads. The control technique is implemented in MATLAB Simulink environment for dynamic load conditions, and the obtained result compensates the harmonic current to a required level (total harmonic distortion of source current is 0.79%) satisfying IEEE 519-1992 standard. [ABSTRACT FROM AUTHOR]

This paper presents the systematic design methodology of a 3.3 kW, level 2 battery charger with improved grid power factor for EV applications. The charging of the battery bank from the utility grid through bridgeless interleaved boost (BIB) converter and the proposed three-level modified series–parallel resonant converter is explained in detail. The proposed topology offers low voltage stress equal to half of the DC link voltage across the switches as three-level is implemented in the resonant stage. The transformer parasitics are taken into consideration and the design of resonant stage for frequency modulation is elaborated. One of the major concerns of the charging system is the grid power factor which is largely affected by power electronic switching operation. The detailed controller design procedure for power factor correction of BIB and DC link voltage regulation is elaborated in this paper. Simulation results obtained using PSIM software prove that the power factor is close to unity with less supply current total harmonic distortion as per IEC 61000-3-2 standard. The proposed resonant converter switches achieve zero voltage switching for above resonant frequency operation. [ABSTRACT FROM AUTHOR]

This paper intends to provide a three-level CUK converter-based on-board electrical vehicle battery charger with improved power quality features. The proposed configuration includes a diode bridge rectifier followed by a DC–DC converter suitable for the universal input voltage variations (85–265 V). It offers reduced voltage stress across the switches, reduced filter size, high efficiency, and improved dynamic response. A feed-forward control scheme is implemented for the proper functioning of the proposed converter under constant current (CC) and constant voltage (CV) modes of operation. In this paper, the mathematical modeling, operational details, and components design of the PFC converter are analyzed in continuous current mode. The simulation study on a 3.2 kW, 400 V proposed converter is carried out with MATLAB Simulink toolbox, and a real-time implementation of the same specifications of the proposed system is developed to verify the simulation study. The steady-state and dynamic behavior of the converter is investigated for power quality features like total harmonics distortion and input power factor with resistive and battery loads. The onboard charger exhibits satisfactory operation in CC and CV modes to a wide range of supply voltage variations. [ABSTRACT FROM AUTHOR]

Electric vehicles (EVs) contain two main power electronics systems, namely, the traction system and the battery charging system, which are not used simultaneously since traction occurs when the EV is travelling and battery charging when the EV is parked. By taking advantage of this interchangeability, a single set of power converters that can perform the functions of both traction and battery charging can be assembled, classified in the literature as integrated battery chargers (IBCs). Several IBC topologies have been proposed in the literature, and the aim of this paper is to present a literature review of IBCs for EVs. In order to better organize the information presented in this paper, the analyzed topologies are divided into classical IBCs, IBCs for switched reluctance machines (SRMs), IBCs with galvanic isolation, IBCs based on multiple traction converters and IBCs based on multiphase machines. A comparison between all these IBCs is subsequently presented, based on both requirements and possible functionalities. [ABSTRACT FROM AUTHOR]

The need to reduce pollution and the shortage of fossil fuels has led to the increased development of hybrid and full electric vehicles. There is also increased development and an increased use of renewable energy resources such as photovoltaic, wind, tidal, etc. These two trends pose serious challenges to the existing grids: a lack of supply power when the demand is high, deficient management of excess power, an increased number off grid faults, grid instabilities and others. One way to increase the penetration of electric vehicles (EV) into the market and to keep the existing grid infrastructure is to combine renewable energy resources with the grid and local battery packs to make EV charging stations. This paper focuses on developing such an EV charging station. The main advantages of the proposed EV charger include the fact that it uses only off-the-shelf inverters, and it is intended to be used in households where the maximum installed power is 3.6 kW to enable fast-charging operation modes or to reduce the costs of energy while charging the EV battery; it can reduce the energy demand from the grid during peak power consumption; it has the potential to lower electrical energy costs; it offers the possibility of vehicle-to-home (V2H) implementation; it is modular (if other technologies become available and more affordable, the consumers can easily update the system, adding more power or adding other types of renewable resources). [ABSTRACT FROM AUTHOR]

The operation of wireless battery chargers at multiple switching frequencies may lead to a noticeable suppression of conducted and radiated electromagnetic interference (EMI) at the cost of decreased efficiency (mainly at lower load resistances) and increased peak and root mean square values of currents of power components of the wireless battery charger. Moreover, the reduction in conducted EMI is only moderate (<8.3 dB). Therefore, a novel approach based on modified resonant circuits and a modified control technique to obtain better reduction in the conducted and radiated EMI without significantly compromising other performance characteristics of the wireless battery charger is proposed and validated by using simulations and experiments. It is shown in this paper that the wireless charger operating at multiple switching frequencies with the proposed approach for the performance improvement has a more effective implementation of the four-switching frequency spread-spectrum technique with better conducted and radiated EMI reduction at all load resistances, lower values of peak and RMS currents at all load resistances, and higher efficiency in constant current mode and in the beginning of constant voltage mode (at lower values of the load resistances) than that of the conventional wireless charger operating at multiple switching frequencies. [ABSTRACT FROM AUTHOR]

This paper proposes an integrated battery charger for electrical vehicles (EVs) employing a three‐phase open‐winding permanent magnet synchronous motor (3p OW‐PMSM), which can be simply modified from a typical star‐connected PMSM. It reutilizes the existing propulsion components to achieve fast charging and vehicle to grid (V2G) operations. Only one nonintegrated inductor is added to realize torque cancelation so that no rotation or vibration is generated. In the fast‐charging and the V2G modes, the current flowing through the inductor is half of one phase grid current, namely, one in six of the total grid currents. The rest five in six of the grid currents flow through the stator windings of the motor. Hence, the proposed integrated system has a high utilization rate of the motor and possesses high power density. In addition, an individual inner current controller for each leg of the AC‐DC converter is employed to ensure the unity power factor, low current harmonics, and torque elimination. In the motor‐drive mode, the equivalent circuit is consistent with the conventional 3p star‐connected motor driver. Therefore, it does not increase the complexity of the motor‐drive control strategy. Finally, simulation and experimental results for fast‐charging, V2G, and propulsion operations verify the feasibility of the proposed scheme. [ABSTRACT FROM AUTHOR]

A 3.3 kW bidirectional charger using an active-clamp flyback circuit with a symmetrical structure is proposed in this paper. Unlike the currently used bidirectional resonant converter, the proposed charger has a simple structure. By adopting a symmetrical design for the proposed charger, it can achieve the same bidirectional gain and efficiency in forward and reverse operation. In addition, it has the advantage of being able to respond to a wide output voltage range through simple pulse-width modulation (PWM) control. Thus, it can be applied to multi-purpose charger designs for a variety of batteries. An elementary flyback converter has the disadvantage of having electrical stress of the switch. An active-clamp circuit is applied to solve this disadvantage and to implement zero-voltage switching (ZVS) on all of the switches. Thus, high efficiency can be achieved at a high frequency using four 1200 V class silicon-carbide field-effect transistors (SiC-FETs). The feasibility of the proposed charger was verified using a prototype converter with input and battery voltages of 400 and 100–450 V, respectively. [ABSTRACT FROM AUTHOR]

The adaptive charging algorithms of today divide the available charging capacity of a charging site between the electric vehicles without knowing how much current each vehicle draws in reality. Thus, they are not able to detect deviations between the current set point at the charging station and the real charging current. This leads to a situation where the charging capacity of the charging site is not used optimally. This paper presents an algorithm including a novel feature, Expected Characteristic Expectation and tested under realistic circumstances. It is demonstrated that the proposed algorithm enhances the adaptability of the charging site, increasing the efficiency of the used network capacity up to about 2 kWh per charging point per day in comparison with the previous benchmark algorithm. The algorithm is able to increase the average monetary benefits of the charging operators by up to around 5.8%, that is 0.6 € per charging point per day. No input, such as departure time, is required from the user. The proposed algorithm has been tested with real electric vehicles and charging stations and is compatible with the IEC 61851 charging standard. The charging algorithm is applicable in practice as it is described in this paper. [ABSTRACT FROM AUTHOR]

In a DC microgrid that involves a battery storage system, the primary energy management is performed by a battery charger/discharger based on a dc/dc power converter. Moreover, the battery charger/discharger is also used to regulate the voltage of the dc bus. One of the challenges at the control level is to regulate the DC bus voltage under battery charge and discharge conditions but also under different relations between the battery and bus voltages. For this reason, this paper proposes a battery charger/discharger based on the Sepic/Zeta converter and an adaptive controller, which provides bidirectional current flow, stable bus voltage, and satisfactory electrical characteristics. The main advantage of the proposed control system is the capability to adapt the controller parameters to any operation condition, which provides a general solution to interface any battery to any bus voltage. This study is focused on the design procedure of both the power converter and the controller, where a detailed mathematical analysis is performed to ensure the system performance and stability. Finally, the proposed solution is validated using an experimental prototype and a practical application case. [ABSTRACT FROM AUTHOR]

In this editorial, a set of recent and relevant bidirectional power converters for EV battery chargers were presented, covering topics such as on-board and off-board EV chargers, slow and fast chargers, integrated chargers, new topologies of power electronics converters, bidirectional wireless chargers, and reconfigurable chargers targeting the bidirectional vehicle-to-vehicle operation mode. Particularly, plug-in battery electric vehicles (EV) have been the main technology supporting a complete transition to electric mobility. This editorial covers key recent papers about bidirectional power converters for EV battery chargers, including traditional on-board and off-board EV chargers, slow single-phase and fast three-phase EV chargers, the possibility of integrated on-board chargers for both motor drivers and charging/discharging batteries, new topologies of multilevel converters with multiple functionalities and their respective control strategies, bidirectional wireless EV battery chargers and their respective technologies, and the possibility of bidirectional EV chargers supporting the direct vehicle-to-vehicle operation mode. Thus, like on-board and off-board EV conductive chargers, wireless EV chargers must also be prepared to operate in the bidirectional mode. [Extracted from the article]

In this paper, six kinds of two-stage ESPs with various ratios of charger and collector units are designed to research the capture enhancement mechanism of submicron particles. The working conditions are optimized by studying the influence of gas velocity, charger current, and electric field strength of collector. Results show that the electrostatic field characteristics of the two-stage ESP with Ra = 1/6 is beneficial to improve the collection efficiency while slightly less stable. The indicator factor of particle charging enhancement effect of two-stage ESP with Ra = 6/1 fluctuates between 0.06 and 0.1, which suggests that the two-stage ESP with a higher proportion of charger units cannot achieve the satisfying performance for the limitation of ionic wind effect. Under comprehensive consideration of ionic wind effect and ozone emission, the two-stage ESP with Ra = 2/5 is selected at the first priority by exerting the advantages of fully particle charging and enough collection space, which has a strong potential in both particle charging enhancement and electric field enhancement. However, for improving the collection efficiency of submicron particle with a size ranging from 0.2 to 0.5 µm which suffers from both of weak particle charging and agglomeration effect, the two-stage ESP with Ra = 4/3 is not recommended. [Display omitted] • Submicron particles with the lowest collection efficiency are selected as target. • Capture enhancement mechanism is investigated by designing two-stage ESPs. • Working conditions are optimized by studying the effect of operating parameters. • The electrostatic capture equipment with appropriate unit proportion is selected. [ABSTRACT FROM AUTHOR]

The dual-active bridge (DAB) topology is commonly preferred in bidirectional applications due to several attractive features, including auto-adjust of power flow, galvanic insulation, wide voltage gain, and zero voltage switching (ZVS) capability over some power ranges. However, the efficiency of the converter drops at light loads because the ZVS range is directly dependent on the circulating current. Assuming that the processed power is variable, the DAB converter's design must find a compromise between extending ZVS ranges and reducing the reactive power processing to ensure higher efficiency. Aiming this compromise, many papers propose hybrid approaches in which the modulation strategy is selected according to the processed power. However, this is not a simple solution because it demands multivariable control and offline optimizations. This paper proposes a modulation strategy to ensure ZVS and reduce the circulating current for the DAB converters. While the usual phase-shift modulation provides ZVS operation in a range of 40% to 100% of rated power, the proposed asymmetrical pulse-width modulation can obtain ZVS operation in a range of 2% to 100% of rated power. Experimental results demonstrated that the proposed strategy improves the converter efficiency for all power ranges, especially at light loads. [ABSTRACT FROM AUTHOR]

This paper presents a dynamic thermal model which predicts the winding temperature of electrical machines at steady-state and transient conditions where windings are used in integrated battery chargers (IBCs) for DC charging in a stationary position. Using winding in high current charging process causes rising winding temperature which affects insulation life. Switched reluctance machines are a proper choice for using in electric vehicles (EVs) because of their advantages such as simple and sturdy structures. IBCs can reduce volume and weight of EVs and total cost is diminished because of integration. The analytical thermal model proposed in this paper can calculates the winding temperature in balanced and unbalanced currents injection because of the phase inductance in each rotor angle is distinct, so current excitation in each phase should be different for obtaining zero total torque and keeping rotor in a stationary position, also a reduced-order model is proposed with minor impact on the accuracy of the model. Special attention has been paid to monitor the winding temperature with considering the motor lifetime in DC charging mode, this view has not been addressed in IBCs before. The proposed model is then validated against experimental results and 3D finite element method. [ABSTRACT FROM AUTHOR]

This paper proposes a mathematic relationship between obtained capacity and the corresponding current rate for the Li‐S and Na‐S conversion batteries. Using experimental data on different conditions of the Li/Na‐S batteries, taken from literature, it is established that the inverse value of obtained capacity is changing linearly with respect to square root of the corresponding applied current rate. The theoretical‐based relationship has been established for the Li‐ion and Na‐ion batteries. Therefore, this paper proposes similar behavior for the conversion and intercalation batteries. The proposed relationship and its beyond approach proffer estimations of: alteration of capacity by rate, optimal cathode mass, corresponding reaction components, and fraction of (in)active particles. Also, they offer a quantitative criterion for performance and rate‐capability, the capability to justify observed phenomena, and also qualification of the powder, preparation, and assembling of the cell. [ABSTRACT FROM AUTHOR]

This paper proposes a new loss modeling and design method for phase shift controlled resonant LLC converter with optimization applied to minimize the overall loss during the whole battery charging process. In this work, the loss model has been formulated more accurately for phase shift controlled LLC converter. One of the contributions in accurate loss modeling is all switching modes of power switches have been investigated in detail in the aspect of zero voltage switching (ZVS) and ZCS occurrence and their related dynamic loss are updated in loss calculation during the whole charging process. In addition, to optimize the copper and core losses of high‐frequency transformer and resonant inductor, a design trend is included in optimization process to calculate the best physical dimensions and winding parameters of magnetic components. A genetic algorithm has been employed for the optimization during the charging process. In this work, the first harmonic approximation (FHA) model was developed and solved by nonlinear Newton–Raphson method in any operating point along one complete charging process. The target of optimization was designing a wall mounted type level 2 battery charger (7.4 kw/32A) for charging a battery pack with specs according to the Nissan Leaf 2011 electric vehicle. For verification of the proposed method, simulation results are provided and also experimental results for a low‐scale prototype are proposed. In this study, the average efficiency along the overall charging process obtained up to 95% in simulation and 84% in experiments. [ABSTRACT FROM AUTHOR]

A wireless battery charger with inductive power transfer (IPT) was proposed in this paper. The commonly used constant-current constant-voltage (CC-CV) charging method is accomplished by a closed-loop controlled IPT with a hybrid resonant circuit on the secondary side. A smooth transition between the CC stage and the CV stage can be made simply by swapping exactly the associated switches on resonant capacitors. The required charging voltage and current are regulated by controlling the phase-shifted angle of the high-frequency inverter on the primary side. To stabilize the charging current and voltage, a closed-loop digital controller was introduced with infrared (IR) transmission feedback. Precise regulation of the resonant inverter on a relative small ranged phase-shifted angle can be realized by two 16-bit microcontroller units (MCUs) with compact encoding and decoding techniques. A hybrid resonant inverter was designed for a 600 W prototype of the proposed IPT battery charger. Experimental results from exemplar cases have demonstrated that the battery charger can provide a stable charging current at the CC stage and then transit smoothly into the CV stage. [ABSTRACT FROM AUTHOR]

This paper deals with developing and implementing a bidirectional galvanically isolated on-board charger of a high-power density. The power density of the new charger was 4 kW/kg and 2.46 kW/dm3, and the maximum efficiency was 96.4% at 3.4 kW. Due to the requirement to achieve a high-power density, a single-stage inverter topology was used. Regarding switching losses, due to the topology of the circuit with so-called hard switching, the switching frequency was set to 150 kHz. A laboratory prototype was built to verify the properties and operating principles of the described charger topology. The on-board charger has been tested in a microgrid test platform. Due to the parasitic properties of the transformer and other electronic components, overvoltage with subsequent oscillations occurred on the primary side of the transformer and damped resonance on its secondary side. These parasitic properties caused interference and especially voltage stress on the semiconductor elements. These undesirable phenomena have been eliminated by adding an active element to the charger topology and a new transistor control strategy. This new switching control strategy of transistors has been patented. [ABSTRACT FROM AUTHOR]

This paper is intended to provide enhanced features of onboard EV battery chargers in terms of improved power quality feature, reduced voltage stress, reduced filter size, high efficiency and fast dynamic response for universal input voltage range (85–265 V). The proposed configuration comprises of three-level quadratic converter suitable to provide high voltage gain. The detailed operation, analysis and control scheme of the proposed converter rated for 3.2 kW, 400 V are studied under simulation and hardware in a loop environment. The on-board charger performances are assessed by charging a 40 Ah lithium ion EV battery under different charging modes. The state of charge of battery decides converter operating mode i.e. constant current and constant voltage mode to charge the battery. Enhancement in the onboard charger is observed in both operating modes tested for wide variation in supply voltages. The results reveal that the operation of converter depicts unity power factor operation, improvement in supply current harmonics and controlling output voltage/current. Under both operating modes, the proposed charger draws sinusoidal supply current from ac mains and its THD is reduced to specified limit prescribed by IEC-61000-3-2. Furthermore, the charger performance is also investigated for EV battery charging operation at wide input voltage variations and found satisfactory. [ABSTRACT FROM AUTHOR]

This paper proposes a positioning-tolerant wireless power transfer technique to compensate the impact of misalignment on the power transmission performance, which is used to implement the wireless charging functionality in a free-positioning manner, thus significantly improving the practicality for roadway-powered electric vehicles (EVs). The key of the proposed wireless power transfer technique is to adopt the gapless alternate-winding topology for the power supply unit to produce an evenly distributed electromagnetic field and the vertical-and-horizontal coil design for the pickup unit to enhance the capability of acquiring energy. Hence, the power transmission can be effectively improved in spite of an offset between the centers of the primary and secondary coils. In this paper, both the computational simulation and experimentation are carried out to verify the feasibility of the proposed positioning-tolerant wireless charging system for roadway-powered EVs. [ABSTRACT FROM AUTHOR]

• This research paper deals with design and development of PV emulator for testing of MPPT algorithm and Battery Charger controller using GA optimized PI controlled DC-DC Buck converter. • Genetic Algorithm has been used to optimize the parameter of the PI controller to emulate the exact behavior of the reference PV model. • The proposed GA optimized PI controlled DC-DC Buck converter based PV emulator provides the successful operation in three region i.e., constant voltage region, variable voltage and current region and constant current region. • The proposed PV emulator has been tested with perturb and observe maximum power point tracking algorithm and constant voltage battery charging control. • The PV emulator was also tested with MPPT algorithm and solar MPPT battery charging control algorithm and it has maximum power point extraction ratio of 97.45% and charging efficiency of 93.9%. • The proposed PV emulator has been successfully realized in real time with low cost microcontroller i.e., control logic for the PV emulator was implemented using Arduino ATmega board. • The developed model was tested and IV and PV characteristics are compared with PV reference model and observed that PV emulator has an emulation efficiency of 98.2%. In this paper, PV emulator is developed using double loop PI controlled DC-DC buck converter. Ambient environmental conditions such as irradiance, temperature and wind speed are considered for creating PV reference model in the PV emulator. The simulation model of the proposed PV emulator is created and tested using MATLAB Simulink package. To validate the effectiveness of the proposed PV emulator, it is tested with different operating conditions such as varying irradiance, temperature and wind speed. The current–voltage and power-voltage characteristic of the PV emulator is compared with PV reference model. The suitability of the PV emulator is tested with MPPT algorithm and battery charging controller in addition to number of objectives. Real time testing of the proposed PV emulator is done experimentally and also corresponding results are discussed. The proposed Solar PV emulator has the following properties: (1) higher bandwidth DC-DC buck converter, (2) extremely reliable performance with lower response time, and (3) lower output voltage and current ripple. [ABSTRACT FROM AUTHOR]