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This brief proposes a low voltage ultra-low power 10-bit 100-MS/s successive approximation register (SAR) analog-to-digital converter (ADC). To overcome the performance degradation due to the signal-related current fluctuation under lower supply voltage, an adaptive-biasing comparator with current self-compensation (CSC) technique is proposed to obtain a constant working current, reducing the minimum supply voltage from 0.7V in conventional ADCs to 0.55V. Since full-scale range shrinks with the supply voltage, voltage undershoot in power rail caused by capacitor digital-to-analog converter (C-DAC) deteriorates effective-number-of-bits (ENOB). Conventional solutions involve enhanced regulators and large decoupling capacitors, which cost remarkable power dissipation and large chip area. This brief presents a pulse-injection undershoot compensation technique which reduces the DAC-related supply fluctuation from a typical 15mV to 1.8mV, and improves the ENOB by 0.4 bit. The prototype was fabricated in TSMC 28nm HPC CMOS technology. The proposed SAR ADC achieves an SNDR of 54.7dB and an SFDR of 68dB with the power consumption of 0.16mW under 0.55V supply voltage, a figure of merit (FoM) of 3.6-fJ/conversion-step is achieved. The chip area of the ADC core is 130μm×225μm.

This paper studies the coordinated use of smart inverters with legacy voltage regulating devices to help increase the energy savings from conservation voltage reduction (CVR) in distribution systems with high photovoltaic penetration. Two voltage optimization algorithms are developed to evaluate the CVR benefit by considering two types of smart inverter functions: aggregated reactive power control and autonomous volt/VAR control. In each algorithm, smart inverters are coordinately controlled with the operation of legacy voltage regulating devices including load tap changers and capacitor banks. Both algorithms are tested on representative utility distribution system models. Simulation results demonstrate that the proposed algorithms can achieve around 1.8-3.6% energy savings when only using legacy voltage regulating devices and an additional 0.3-0.9% when adding smart inverters.

The steep voltage slopes of today’s wide-bandgap (WBG), fast-switching power semiconductors — like SiC and GaN — lead amongst other challenges to reflection on long cables and thereby overvoltage at inductive loads. To enable the use of these inverters with motors without specially reinforced insulation the voltage slopes need to be slowed down. This article presents a new low-loss countermeasure, which involves the parallel connection of two half-bridges via an interphase transformer. For this one half-bridge is delayed relative to the other one by a delay tuned to a resonant circuit. Undesired DC components in the cross-current of the interphase transformer occur due to non-idealities in the voltage symmetry. The subsequent DC magnetization ultimately can cause the core to saturate. The paper describes the effects due to inaccurate timings and the aspects to keep in mind when dimensioning the magnetic core. Also, this article describes an approach to deal with the undesired current components using a closed-loop control. For that, a special differential-mode shunt is used which enables a dedicated measurement of the cross-current mean value and mitigates the influence of the switching frequency. Finally, the controller concept is presented. The controller is implemented and verified on a 500 kVA SiC inverter test bench.

Thomson coil actuators consist of an electric coil repelling a metallic disk. They are considered the fastest electromagnetic actuators for short travels and for this reason are favored for DC circuit breakers. Although the basic physics are understood, the actuator’s few components are very interdependent, making for a difficult analysis. Actuator design so far has thus been limited to trial and error based on finite-element models. In this paper, a novel approach is presented based on the electromagnetic frequency response of the actuator. This method is shown to be an intriguing analysis tool and various actuator design directions are presented. Experimental results provide a confirmation of the analysis.

There is a growing demand for multi-port power converters for managing multiple energy sources and loads. To that end, a dual-input single-output dc-dc converter is proposed in this article. The converter integrates two different and low-voltage dc sources into a dc bus. Pulse width modulation is used to control the transfer energy from the input ports to the output port. The discontinuous conduction mode (DCM) operation of the converter has enabled the soft-switching operation in the primary switches. Moreover, it helps avoid the high-frequency transformer (HFT) saturation when the two input voltage sources have different values. The detailed analysis of the proposed dc-dc converter is presented in this article along with the simulation and experimental results obtained from a 150 W hardware prototype to validate its operation.

This paper presents the internal energy balance of a modular multilevel cascade converter with photovoltaic arrays as distributed energy resources. This converter is characterized by a modular arm structure composed of bidirectional cascaded chopper cells with floating DC capacitors, where each cell is connected to a photovoltaic array through a DC/DC converter. A continuous model and a control method are proposed to maintain the internal energy balance and achieve independent voltage control of all the floating DC capacitors, allowing the tracking of the maximum power point for each photovoltaic array. The operation with asymmetric energy generation at different levels of irradiance is discussed to maintain the internal energy balance without distortions in the DC link and AC output currents, focusing on the operation with individual cells with zero energy generated from PV array. This topology and control method is suitable for hybrid multi-terminal high voltage DC systems and hybrid generation systems, such as wind-solar energy systems. Experiments are presented to validate the proposed model and control method.

A new dc-dc converter with high voltage gain is proposed in this study. The proposed converter consists of two switches which are turned on and off simultaneously. Additionally, two Switched-Capacitor (SC) cells and one Energy Storage (ES) cell are utilized in the structure of the proposed converter. These result in high voltage gains at low values of the duty cycle. Besides, the voltage stress across the power devices is low and below half of the output voltage. Therefore, the MOSFET switches with low RDS-on and devices with reduced nominal voltage can be used in the proposed converter which in turn reduces the conduction and turn-on losses. The analysis of the voltage and current stresses of the devices is accomplished. The circuit performance is compared with other solutions in the literature in terms of voltage gain and normalized voltage stress of switches and diodes. Eventually, in order to verify the theoretical analysis, the experimental results are provided.

During last decade biomedical devices have become more and more performing, covering an increasing number of usages. In particular, subcutaneous devices represent one the most invasive yet innovative application; their battery management is one of the most challenging topics because, once implanted, they can be handled only through surgery, so wireless charge is the only way to feed subcutaneous systems with appreciable energy in a controlled manner. But differently from conventional consumer devices, in this scenario the energy delivered necessarily runs into human body and tissues, so the main challenge consists in maximizing the "energy delivered vs. energy dissipated in tissues" ratio, in order to guarantee human safety first while also conveying an appreciable amount of energy to the implanted device After analysing the state-of-the-art of the principal techniques, this paper proposes a novel architecture for low-power wireless charging, based on a Wiegand sensor used as a transducer in order to fulfill all the requirements from both electrical and medical points of view; such architecture is implemented inside an IC prototype in 0.35 μm lithography that acts as an ultra-low-power DC-DC buck converter and battery manager.

Stealth aircraft use Stealth Technology in order to evade recognition by utilizing mix of highlights with the goal that Aircraft can invade with RADAR and furthermore decrease the deceivability in “radio frequency (RF) range”, sound and infrared visual. During the most recent decades, stealth technology has demonstrated to be one of the best methodologies to the extent the undertaking to escape radar systems is concerned. Stealth intends to evade the recognition or attempt to cover up, for planes, avoiding radar implied stealth. The idea utilized in the stealth innovation isn’t so difficult. It utilizes the guideline to retain and mirror the radar waves. Airplane redirects the radar waves in different ways and limits the radar waves which return back to radar. Another marvel which permits the air ship maintain completely the incoming radar wavelengths to inhabit the electromagnetic reincorporated energy in various way. The structure and material used to manufacture air ship choose the degree of stealth accomplish via air ship. The thought for the radar radio wire to release Radio energy that is then returned through any item that occurs to recognize. The time taken for the reflection to come is measure by the radar radio wire and it can tell how far off an object is.

Here suggests the formation of a pair of CIBCs with raised performance for solar application by employing maximum power point tracking method. The suggested two level CIBCs contains a pair of interlaced boost converter (CIBC) coupled in concatenation to gather the utmost power from sunlight and to supply a rise in output voltage with low ripple. The simulation of PV system and power converters has been done MATLAB/simulink.

Solar energy, wind energy etc. are the main sustainable energy sources used around the world. These sustainable energy sources are used in day-to-day life in various forms for numerous purposes. One of the highly used sustainable energy sources is the solar energy which with the help of photovoltaic (PV) cells can be made use for the generation of electrical power. However, these sources generate less voltage values and thus it requires a high gain converter. In this paper, a modified Luo with flyback DC to DC converter is presented that assures high voltage gain, single switch, less stress across the components and less ripple current. Furthermore, the simulations along with the hardware prototype for the presented converter is carried out and presented in this paper.

In the Internet of Things (IoT) the physical objects network is described as “things” linked to sensors, software and other technologies to connect and share information through the Internet with other devices and systems. The floods lead to large losses of life and property in several countries. However, the absence of sufficient technology results in further death and property losses as a result of flooding in developed countries. This is because of a lack of flood alert systems. The objective of this paper is to monitor the flood situation and provide a text message warning in the event of a threat. The main aim of this paper is to detect rising river water levels at a safe distance away from the railways and to allow the respective authorities to take appropriate measures by means of SMS. A sensor is a system that senses and reacts to certain physical data. The 8051 microcontrollers were produced by Intel in 1981. The microcontroller is 8-bit. It has 40 DIP pins, 4 kb of ROM stores and 128 bytes of RAM and two timers and 16 bits. It is equipped with 2 timers. There are four parallel 8-bit ports that are programmable and adjustable as necessary. The hardware device that uses GSM mobile technology for the provision of an information link with a remote network is a GSM modem or a GSM module. A float switch is a level sensor type, a fluid control system that is used inside a tank. A condenser is a tool that stores electrical energy in an electric field. It's a passive electronic feature with two terminals. A LED is a semiconductor light source that transmits light through the flowing current. Liquid Crystal Display stands for LCD. It is a thin, flat display device used in a variety of electronics. A digital electronic level shifter is a system used in the transformation of signs from one logic or voltage domain to another, also known as logic level shifter or voltage level Translation. A diode is an electronic component with a two-terminal that mainly conducts current in one direction, with low resistance and high resistance in one direction. The aim of this paper is to detect early Flood and give early warnings to Needy people.

Battery power has been a popular choice of delivering DC power to many portable RF systems including wireless sensor nodes/internet of Everything (IoE). An autonomously powered RF system of the orders of 100’s of µwatts is becoming increasingly popular in recent times because of integrated solutions in energy harvesting. The minimum sensitivity of an RF energy harvester and the targeted deliverable output voltage for a specific load resistance are dictated by threshold voltage of transistors used and reverse leakage of such transistors. A detailed look into the architectures of rectifiers can help tackle design problems in the RF-DC conversion process. So in this work we focused on the design of integrated RF energy harvesting by studying four important architectures of RF-DC converters. To achieve a fair comparison between these architectures, a matching network operating at 0.8 MHz is designed and applied for simulation. All of these converters are tested in LT-SPICE XVII using the same designed matching network and the rectifiers are implemented in 180 nm CMOS technology.

As the technology is scaled-down and with a decrease in oxide thickness, the effect of NBTI is a major reliability issue in semiconductor industries. NBTI is an aging phenomenon in which the PMOS transistor degraded over time. Deviation in the threshold voltage of PMOS transistor results from NBTI with stress time which affects various parameter of SRAM memory such as degradation in drain current, RSNM, HSNM and access time. NBTI induced aging effect on 6 T and 8 T SRAM cell have been analyzed in this paper for the stress time of 10 years. The reliability parameters of 6 T SRAM cell obtained from simulation result shows there is 6.53%, 23.86%, 3.36% and 13.42% change in Hold SNM (HSNM), Read SNM (RSNM), Write margin and standby leakage current respectively after 10 years. Similarly in 8 T SRAM cell HSNM, RSNM, Write margin and leakage current changes by 5.81%, 5.01%, 3.11%, and 13.24% respectively. This paper also presents the leakage current sensing technique based NBTI monitoring sensor using NMOS transistors only. The sensitivity of the sensor is 40 µV/nA and the linearity of the sensor is upto the practical leakage current range of SRAM cell. Thus we can conclude that the proposed sensor works fine with greater linearity and sensitivity.

The project is envisioned to convert DC output combined from the micro grid as the common dc bus into AC voltage. S3 inverter is used to obtain appropriate sine wave as output. Inverter generally has high Total Harmonic Distortion (THD) and by using our implementation on this project, less THD could be achieved. This topology of the inverter has only three semiconductor switches, one with a large frequency and another with a fundamental frequency. Therefore, the inverter is designated the S3.

Now adays Very Large-Scale Integration (VLSI) circuits have good or great demand. Because CMOS circuit design having less power consumption. Transistors on the chip is doubled every two years, according to Moore’s law. So, it means transistor size is decreasing. This leads to increase the chip density and decrease the device size. The write and read depending on the bitline and bitline bar discharging and charging. When design the memory in below 16 nm uses Fin Field effect Transistor (FinFET) technology instead of CMOS (Complementary metal oxide semiconductor field effect transistor). Because to avoid short channel effect. Comparing leakage power, dynamic power and static power at 90 nm technology and write delay, read delay at both 90 nm and 45 nm technology in nine transistors (9 t), eight transistor (8 t) and six transistor (6 t) sram cell.

This paper presents, a three-phase grid interfaced charging station (CS) for electrical vehicle (EV). It interacts with the grid to compensate for the reactive power. The charging station operates in various modes (i) charging/discharging of EV battery, (ii) compensation of reactive power (iii) both concurrent charging and compensation of harmonics current and (iv) concurrent discharging and compensation of harmonics current. The CS while in grid connected mode, operates under distorted and unbalance grid conditions. The control of the charging station is designed such that the reference grid currents synchronize with the phase voltages at PCC (Point of Common Coupling). If the grid losses synchronism then the charging station works in islanded mode and PV source charges the EV battery. The performance of the charging station is tested under various dynamic conditions and the grid currents distortion levels are in the limits as recommended by the standard IEEE-519.

This paper discusses the analysis of a Quasi Z source inverter with a trouble-free boost control tactic for renewable energy applications. The non-availability of uninterrupted renewable energy sources in atmosphere weather conditions raises variation in output voltage and currents. This may affects the performance of conventional inverters with potential source (VSI), current source connected (CSI) and impedance source inverter (ZSI). To overcome the drawback of VSI, CSI and ZSI a quasi-Z source inverters (QZSI) are used. The QZSI performs multiple operations such as DC-to-DC, AC-to-AC, AC-to-DC and DC- to-AC conversions. Also, it may be used for each buck and boost operation, using the shoot through state. The QZSI is derived from the ZSI topology, with a minor modification of the impedance network and overcomes the troubles facing in ZSI. The design construction and simulation study of quasi-Z source inverter is performed using MATLAB/Simulink environment.

© Copyright 2022 The Author(s). In this article, with the increased disruptions faced by businesses and the occurrence of natural disasters in the world, supply chain resilience remains a major challenge especially for small- and medium-sized enterprises (SMEs). Despite the relevance of SMEs to the economy, there is limited scholarly work on resilience practices in SMEs and a limited understanding of how SMEs can achieve resilience. To understand the role of supply chain resilience in SMEs, we undertake a systematic literature review (SLR), which results in the identification and analysis of 101 journal articles, published between 2006 and 2019, on SME supply chain resilience. Our analysis into SME supply chain resilience highlights four focal areas: 1) the role of collaboration and culture; 2) the role of SMEs’ capabilities; 3) the role of Information Systems; and (4) the role of cost and financing. Our SLR investigation identifies future research directions and focal areas tailored to SMEs to help them to assess and develop their supply chain resilience.

The paper proposes an integrated power converter (IPC) with driving/charging capabilities for 4-phase switched reluctance motor (SRM) drive based electric vehicle (EV) application. With the proposed IPC, only two current sensors are employed for measuring phase currents under all operating conditions. The proposed IPC integrates three circuits. Firstly, during the SRM driving mode, the proposed IPC is utilized as an improved miller converter. Secondly, during battery charging mode, the proposed IPC is utilized as an on-board battery charger which is based on a bridgeless boost power factor correction circuit (PFCC) that incorporates two DC-DC boost converters. The on-board battery charger is realized by utilizing the existing power electronic switches in the proposed IPC and all the phase windings as charging inductors. Third, a front-end bidirectional DC-DC converter for maintaining voltage and current balance between IPC DC-bus and battery. During driving mode, the front-end converter boosts the battery voltage to the IPC DC bus voltage. And during regeneration/braking, the stored magnetic energy is used to charge the battery in constant-current (CC) mode via the front-end converter. During battery charging via AC grid, the bridgeless boost PFCC and the front-end converter operating in buck mode charges the battery in CC/ constant-voltage (CV) modes without stepping down the AC grid voltage. The claims of the proposed IPC are validated through simulation and experimental verifications.

Multilevel topologies with SiC devices for medium voltage (MV) motor drive have advantages to reduce the harmonics and device voltage stress as well as to increase the efficiency. However, with the application of SiC devices, the reflected wave phenomenon still happens in multilevel motor drive due to its high dv/dt, resulting in overvoltage at motor terminals. This paper proposed a T-type circuit based active reflected wave canceller (ARWC) to suppress the overvoltage of a M-level motor drives with reduced voltage rating of Vdc/(M-1). A coupled inductor is applied to isolate the ARWC output and the main inverter. In addition, the coupled inductor is designed with a small resistor to allow low current flowing into ARWC. The proposed ARWC configuration can be applied for general multilevel topologies. A 3-level ANPC converter with 3.3 kV SiC device is built in the laboratory. A 1.2 kV SiC module is applied in the proposed ARWC. The experimental results at 1.6 kV Vdc and 16 A (RMS) load current with and without proposed ARWC are provided and compared to verify the validity of proposed method.

In this paper, an enhanced three-arm alternate arm multilevel converter (AAMC), called T-type AAMC (T-AAMC), is proposed for achieving dc fault ride-through capability with reduced semiconductor power devices compared to the hybrid modular multilevel converter (MMC). The upper and lower dc arms of T-AAMC are formed by half-bridge submodules and series devices for lower construction costs, while the ac arm uses full-bridge submodules to realize dc fault tolerance. Firstly, the arm phase-shift conducting modulation is applied for energy balance of converter stacks under wide-range operation by adjusting the arm phase-shift angle to match ac grid voltage and power factor. Then, the submodule number, power device number and submodule capacitance are evaluated for T-AAMC under optimized modulation design. Analyses illustrate that 43% submodules, 17% power devices and 44% energy storage requirement are reduced with the proposed topology than that with hybrid MMC. Furthermore, the closed-loop control system is designed to dynamically regulate the energy sharing between dc and ac stacks. Finally, full-scale simulations and down-scaled experiments are performed to verify the feasibility of the proposed converter and the theoretical analysis of its modulation and implementation.

In this paper, a non-isolated dc-dc high step-up converter with passive switched-inductor-capacitor network is proposed, which is applicable for the required high gain voltage low power applications, such as battery-powered LED lighting systems and high-intensity mobile discharge lamps. The proposed circuit can produce higher gain voltage with small duty cycle, which decreases the voltage stress and conduction power loss on the active switches. In contrast to other non-isolated dc converters, by using the same or analogous number of passive/active components in circuit topology, the proposed topology has lower voltage stresses across capacitors and diodes, lower inductor current stresses. Therefore, the efficiency and reliability of the circuit topology can be ameliorated. The theoretical principle, parameter design guideline, small-signal dynamic analysis, power loss analysis and performance comparison with other dc-dc non-isolated converters have been implemented. Finally, a 200 W experimental setup is built and tested with an input dc voltage of 36V–60V and an output voltage of 200V to validate the aforementioned merits of the proposed circuit.

With the advent of wearable technologies, Human Body Communication (HBC) has emerged as a physically secure and power-efficient alternative to the otherwise ubiquitous Wireless Body Area Network (WBAN). Whereas the most investigated nodes of HBC have been Electric and Electro-quasistatic (EQS) Capacitive and Galvanic, recently Magnetic HBC (M-HBC) has been proposed as a viable alternative. Previous works have investigated M-HBC through an application point of view, without developing a fundamental working principle for the same. In this paper, for the first time, a ground up analysis has been performed to study the possible effects and contributions of the human body channel in M-HBC over a broad frequency range (1kHz to 10 GHz), by detailed electromagnetic simulations and supporting experiments. The results show that while M-HBC can be successfully operated as a body area network, the human body itself plays a minimal or negligible role in it's functionality. For frequencies less than about 30 MHz, in the domain of operation of Magneto-quasistatic (MQS) HBC, the human body is transparent to the quasistatic magnetic field. Conversely for higher frequencies, the conductive nature of human tissues end up attenuating Magnetic HBC fields due to Eddy currents induced in body tissues, eliminating the possibility of the body to support efficient waveguide modes. With this better understanding at hand, different modes of operations of MQS HBC have been outlined for both high impedance capacitive and 50 Ohm termination cases, and their performances have been compared with EQS HBC for similar sized devices, over varying distance between TX and RX. The resulting report presents the first fundamental understanding towards M-HBC operation and its contrast with EQS HBC, aiding HBC device designers to make educated design decisions, depending on mode of applications., Submitted to Transactions on Biomedical Engineering

Recently, IGCTs have shown a great potential for the soft-switching dc transformer applications based on LLC resonant converter. The zero-voltage switching that is present in this converter topology enables an operation of IGCTs without clamping circuit and with significantly higher switching frequencies, while maintaining the superiorly low conduction losses. The high voltage and current ratings of the IGCTs make them a preferred choice for an efficient bulk power transmission. This paper shows how gate units for IGCTs can be optimized for this soft-switching application. It presents a simplification of the driving topology and the design process for high switching frequencies. This results in low power consumption and a very small size of the gate unit. The prototype of the gate unit is built and experimentally validated in a 2.5 kV 0.75 kA resonant operation of the IGCT.

The demand for high-density, high-efficiency bi-directional battery chargers is driven by the fast development of energy storage system in renewable energy system, micro-grid, and transportation electrification. Isolated dc-dc converter that interfaces a battery with a variable voltage range is one of the critical components. Input-parallel output-series (IPOS) partial power (PP) converter is considered a promising high-efficiency, high density solution because only a fraction of power is processed via multi-stage converters to regulate the output voltage. However, due to the tight coupling between two dc transformers (DCXs), the design of PP converter is complicated. To solve this issue, a design procedure for a bi-directional soft-switching resonant type PP converter is proposed. In the parameters design part, a decoupled design method is proposed to simplify the DCXs design. With this method, two DCXs can be designed separately, and the typical optimization method can be easily applied. As for the hardware design part, to minimize the ac loop inductance and resistance, a 2-directions (2-D) flux cancelation method and an “intra-leaving” winding structure are proposed for circuit layout and high-frequency transformer to obtain high operation efficiency and power density. Finally, the whole design procedure is verified by an 18 kW rated, 25 kW peak, prototype operating at 500 kHz. The realized PP converter features a peak efficiency of 98. 8% and a power density of 142 W/in3. This article is accompanied by two videos demonstrating the dynamic voltage regulation test and the efficiency measurement.

Wireless power and bidirectional wireless data transfer system using a conventional 2-coil inductive link is presented for Internet-of-Things (IoT) and mobile applications without any additional coil or antenna. The proposed system utilizes the dual-band frequency shift-keying (FSK) and the load shift-keying (LSK) for the downlink and uplink telemetries, respectively, while about 140 mW power is delivered to the Rx in the 2-coil inductive link. The data rates for downlink and uplink telemetries are 800 kbps and 14 kbps with bit error rate (BERs) of 3.1210^(-5) and less than 10^(-6) at 10 mm distance, respectively.

This paper proposes a low-profile coplanar magnetic coupling resonance wireless power transfer system, which can be expanded segment by segment to power more receivers over a long distance with load-independent constant current output. Due to the low structural profile, it can easily conform to the environment such as desktops, floors, and walls, occupying a small space. By placing low-profile ferrite plates on or under the junctions of adjacent coplanar coils, the main coupling coefficients of the adjacent coils are significantly enhanced and therefore the power transmission efficiency (PTE) of the system is greatly improved. With the fixed operating frequency, load- independent current characteristics, simple structure, coplanarity with the environment, good scalability and high PTE, the system can be easily utilized in various medium and long-range multi- load WPT applications. The paper describes its principle in detail and clarifies the influence of losses on system performance such as output current characteristics, PTE and the maximum number of the charging segments. The experimental platform with two and three receivers was established to verify the theory, and the measurement results are in good agreement with the theoretical analysis. The maximum measured PTE reached 93.8% and 93.6% for two and three receivers, respectively.

Conventional digital LLC Synchronous Rectifier (SR) control typically uses detection circuits to sense the drain-source voltage of SR MOSFET in low output voltage applications, or gives SR duty cycle only considering the switching frequency in the microcontroller. They are difficult to be applied to the applications of 700 V high voltage and 6.6 kW high power directly due to the high dv/dt and large SR duty cycle variations, which poses serious challenge for SRs control. A bidirectional impedance-based SR driving scheme is presented for high voltage SiC LLC converter. Based on the LLC equivalent impedance, mathematical models are built to calculate the SR on-time in the forward and reverse modes, which can be tuned timely when the switching frequency and load vary. Thus, both bidirectional LLC performance with high efficiency and high immunity to the switching noise can be achieved without adding auxiliary circuits. A prototype of 300-kHz 6.6-kW SiC bidirectional LLC charger was built. Compared to the conventional SR method, the LLC efficiencies improve 0.3% in the forward and reverse modes at full load by using the proposed SR driving scheme.

Fuel cell electric vehicles (FCEVs) have batteries to mitigate problems such as the inability to store energy, poor response speed, and low power density. In the conventional power conversion system, the fuel cell (FC) and battery can be connected to the output load via two independent converters, namely a unidirectional converter for powering with the FC and a bidirectional converter for powering and regenerating via the battery. The conventional converter has a simple structure; it achieves specific operating modes that are required in various driving situations. However, it has two inductors and many operating switches when the FC and battery are simultaneously used. In addition, all the switches have high voltage stresses. These factors can degrade the overall power density and efficiency. Thus, an integrated converter with single inductor is proposed in this paper. By employing a battery mode selection cell (BMSC), the two converters can be integrated with only one inductor. Moreover, the number of operating switches is reduced during powering, and low voltage-rated semiconductor devices can be used. Therefore, the proposed converter can achieve high power density and low conduction and core losses. The validity of the proposed converter was demonstrated by the experiments under various operating conditions.

This paper introduces a new coupled inductor based dual-input ultra-high step-up DC-DC converter with a high voltage conversion ratio, low voltage stress across semiconductor components, and high efficiency features. The coupled inductor and voltage multiplier circuit (VMC) techniques have been utilized to enhance the voltage gain. The blocking voltages of power switches are clamped by VMC at low values and can be controlled via the turn ratio of the coupled inductors that decreases the voltage rate of power switches and converters cost. The presented dual-input structure can transfer power to the load from two independent voltage sources. Also, the inputs and output ports are common ground, which can reduce the electromagnetic interference (EMI) influences. Operation modes delineation, steady-state analysis, and comparison section are provided for describing the proposed structure performance. Finally, to confirm the effectiveness of the presented topology, experimental waveforms with a 200 W output power at 50 kHz operating frequency are presented.

Non-isolated high-voltage gain soft-switching dc-dc converter is an ideal candidate for distributed generation system converters. This paper proposes a high-voltage gain soft switching quasi-Z-source dc-dc converter. The converter integrates a coupled inductor and switched capacitor into a quasi-Z-source network. Soft switching is achieved for all active devices in the converter by controlling the auxiliary switch Sa. By inheriting the advantages of the quasi-Z-source network and coupled-inductor/switched-capacitor, the converter has high voltage gain, high efficiency, low input current ripple, low voltage spike of main switch, and common ground. In addition, the efficiency of the converter is improved by recycling the energy of leakage inductance, resulting from an inherent active clamp of the main switch. The steady-state operation, voltage relationship, current/voltage stress, and power dissipation of each component of the converter have been analyzed and derived in detail. The properties of the proposed converter are verified by designing a 200 W prototype in the laboratory. When the input voltage is 48 V and the output voltage is 380 V, the converter efficiency reaches 96.92%, while the efficiency is 93% in a hard switching. The key waveforms of the converter obtained from the experiment agree well with the theoretical analysis results.

A Phase-shifted full-bridge (PSFB) converter is widely used in various applications due to its soft-switching characteristics. However, one of the recognized shortcomings of the PSFB converter is that it cannot simultaneously have a wide soft switching range and a small secondary-side duty cycle loss. The shortcoming hinders the high frequency and high efficiency of the converter. In this paper, the change of the energy demand of the converter on the external series inductor with input voltage and load is analyzed. On this basis, a variable saturation inductor with controllable energy is proposed to meet the energy demand and solve the problem of core heating. The controllable change characteristics of the inductor energy are studied directly instead of the controllable change of the inductance value. By adjusting the inductor energy, the PSFB can not only achieve soft switching under light loads, but also reduce duty cycle loss under heavy loads. Theoretical analysis and experimental verification are carried out on the soft switching and duty cycle loss of the converter. Since the transformer ratio can be increased due to the smaller duty cycle loss. The efficiency of the converter can be further improved.