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Gallium nitride (GaN) devices switch faster than silicon devices, making them more vulnerable to significant switching oscillations. To reduce the effect of crosstalk in GaN High Electron Mobility Transistor (GaN HEMT)-based bridges, this paper introduces a passive clamp circuit to restrain gate source voltage oscillations. Utilizing resistive and capacitive diodes, as well as diodes and transistors, a bootstrap driving circuit can be established. This circuit forms a low impedance Miller current path from the driving IC to the GaN device, which decreases the impact of both positive and negative crosstalk. Employing resistive and capacitive diodes, as well as diodes and transistors, a bootstrap driving circuit can be established. This circuit creates a low impedance Miller current path from the driving IC to the GaN device, reducing the effects of the positive and negative crosstalk. This method, which mostly uses passive components, simplifies the circuit design in comparison to other passive gate driver methods. Through dual-pulse testing with a GS661008P, its capacity to suppress positive and negative crosstalk in GaN devices has been confirmed. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new high voltage gain quasi Z‐source inverter consisting of a switched‐inductor unit. A coupled inductor including three windings is utilized in structure of the switched inductor in a way to increase voltage gain effectively. In addition, the configuration includes an active switch with low number of components that has positive effects on voltage gain and two of its components recycles stored energy of the coupled inductor similar to a clamp circuit. The converter boosts voltage appropriately in low shoot‐through duty cycles and transfers power with a continuous input current, leading to a reduction in losses, requiring smaller output filter and improving the efficiency. Also, the converter can operate in high modulation index for similar voltage gains compared to the other works which improves quality of outputs. Low number of components and fewer cores for inductors are considered during the design of the converter, causing some superiorities for it in comparisons. In addition, the presented converter has appropriate condition from the viewpoint of voltage stress on its diodes. To validate quality of the converter performance, a 240‐W prototype is prepared that converts 35‐ to 60‐V DC to three‐phase sinusoidal voltages where effective voltage of each phase is equal to 110 V. [ABSTRACT FROM AUTHOR]

In this paper, the clamping effect introduced by several diode-based configurations used for the implementation of the high-value resistors in quasi-floating-gate circuits is analyzed and characterized. In contrast to previous approaches where a parasitic diode is treated as a simple high-value resistor reducing the circuit complexity, in this case the analysis considers the diode behavior which leads to a clamping circuit. This clamping circuit introduces an unwanted amplitude-dependent offset voltage, which affects the performance moving the quiescent point at the quasi-floating-gate transistors. A new anti-parallel diode configuration for quasi-floating-gate applications is proposed in this work, which eliminates this unwanted offset voltage. The proposed design is validated using simulations and experimental data in a CMOS 0.35- μ m technology. [ABSTRACT FROM AUTHOR]

In this paper a new non-isolated converter with ultra-high voltage gain is presented. The proposed converter utilises coupled inductors, lift circuits and interleaved technique to convert low-level DC voltages to high-level DC voltages without high turn ratios or large duty cycles. Winding-cross-coupled inductors are employed to raise the voltage ratio. The voltage and current stress of semiconductors are reduced, which causes low conduction losses and improves the efficiency. The way the clamp circuit is used limits not only the spike voltages but also effect on the conversion ratio of the proposed converter and make it larger. The main features of this converter are high voltage gain, low voltage stress of semiconductors, low reverse recovery of diodes, low input current ripple, low conduction loss and high efficiency. A prototype of the proposed circuit is constructed in laboratory at 100 W converting 20 V to 450 V. The experimental results are compared with theoretical analysis which verifies them. [ABSTRACT FROM AUTHOR]

In some application scenarios of new energy, high voltage gain DC–DC converters are widely employed especially for photovoltaic systems, fuel cell systems, and electric vehicles. The two-stage cascade boost integrated with a coupled-inductor and diode-capacitor voltage multiplier cell has been widely researched due to the advantages of a quadratic voltage gain and low voltage stress for the semiconductor devices. In this paper, the universal ZVS design for a family of quadratic converter is given. The proposed method maintains an extremely high voltage conversion ratio and low voltage stress on the power devices. In addition, the problem of the voltage gain being influenced by the load due to a small excitation inductance selection is solved. Moreover, ZVS operation for all of the switches and ZCS operation for most of the diodes are achieved to lower switching loss and suppress voltage spikes. The active clamp circuit is applied to lower the voltage stress and to control the ZVS operation. The design and operation principles, along with steady state and efficiency analyses of a specific converter are discussed in detail. In addition, a detailed comparison is presented among some similar topologies. Finally, a 320 W prototype circuit is implemented in laboratory to verify the performance of the proposed converter. [ABSTRACT FROM AUTHOR]

Two types of asymmetric switched-capacitor five-level single-phase DC-AC inverters are presented based on the clamping half-bridge circuit and the output half-bridge circuit. Furthermore, the switches of the two proposed circuits can be driven by half-bridge gate drivers and can be modularized. Moreover, the detailed analysis of the operation principle, design of clamping capacitor and output filter of these two inverters are presented. Finally, the feasibility and validity of the proposed structures are verified by PSIM-simulated results and experimental results using FPGA as the control kernel, respectively. [ABSTRACT FROM AUTHOR]

This research presented the utilization of Safety Transient Voltage Suppressors (STVS) in the track circuits of railway signaling systems, occurring during circuit switching due to changes in track occupancy conditions, resulting in damage and malfunction of the BR966F2 relay. The study employed Failure Modes and Effect Analysis (FMEA) combined with 1kV actual transient overvoltage testing featuring a waveform slope of 184/380 μs. Results revealed two transient voltage suppression levels encompassing Set A_(a,b), Set B_(a) and Set C_(a,b) as well as Set A//Set B//Set C and All Mode. These configurations achieved a clamping voltage of 41.6 V, categorized as Stage 1. Configurations like Set A_(c), Set B_(b,c) and Set C_(c) displayed increased series circuit behavior leading to a clamping voltage of 48.6 V, categorized as Stage 2. The application of STVS device in the track circuit of the signaling system reduced the transient voltage by diversion of the Transient Current or ISTVS through the STVS device into the ground system or the clamping voltage at the STVS device. This prevented the transient power from flowing into and damaging the relays of the track circuit, leaving only the clamping voltage with a missing peak wave. This contributed to the stability of the track circuit within the railway signaling system while also raising the Safety Integrity Level (SIL) to a higher standard, in accordance with the specifications of IEC 16508-4 and the unique requirements of the State Railway of Thailand. These enhancements increased the advanced safety system within the track circuit, particularly for train control and train operation functions of the State Railway of Thailand. [ABSTRACT FROM AUTHOR]

Summary: A coupled inductor based on dual switches buck‐boost converter is proposed in the article, which can be used in renewable energy applications. A wide conversion ratio can be realized by regulating turns ratio of the coupled inductor and the duty cycle. The topology has a quadratic‐like voltage gain, and the low voltage stress and current stress. Combing the passive clamping circuit to recover leakage energy, the voltage spikes of power switches are suppressed, improving the efficiency. Moreover, it has the merits of continuous input current and common ground. To demonstrate the superior performances of the presented converter, the principle of operation and steady‐state analysis are presented in detail. At last, a 100‐W experimental prototype was designed to verify the correctness of the theoretical analysis, with a maximum efficiency of 95.7% in step‐up mode and 96.8% in step‐down mode. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of friction on the buckling behavior of a thin, shallow, elastic spherical shell under uniform external pressure based on an axisymmetric model of the finite element method. The study examines a combination of different geometric parameters with three different types of boundary conditions: clamped, hinged, and frictional ends with a wide range of friction coefficients. Friction has a significant influence on the buckling response of the spherical shell for all geometric parameters. In general, the critical pressure decreases as the friction coefficient or geometric parameter decreases. The buckling behavior of the frictional end with small friction coefficients presents an obvious difference compared to the results of high coefficients. For certain geometric parameters, the buckling mode of the spherical shell is transited because of changing the friction coefficient. A buckling map that describes the dependence of critical pressure on both friction coefficient and geometric parameter combined with buckling mode is generated. This map can be applied to the design of the spherical shell against buckling. [ABSTRACT FROM AUTHOR]

This paper presents a current source inverter (CSI) with zero-voltage-switching (ZVS) for low-input voltage PMSM application. And its working principle, space vector modulation (SVM) method, high-frequency switching process are analyzed in detail. The detailed ZVS realization conditions are also designed. The proposed circuit is consisted of a high-gain buck-boost chopper circuit, a three-phase bridge and a C filter, it has the advantage of a wide output voltage range. The proposed modulation method realizes SVM control due to the optimized energy storage mode. The proposed soft-switching scheme realizes the ZVS of the energy storage switch by designing the resonance parameters and controlling the turn-on time of the active clamp circuit. The feasibility and advancement of the proposed CSI drive system are verified by 24VDC/1 kW prototype experiments. [ABSTRACT FROM AUTHOR]

In accordance with the requirements of unmanned robot driving power supply for power supply reliability, strong power output, and portability, this paper introduces a design scheme for unmanned robot driving power supply on the basis of a flyback converter, establishes the mathematical model of driving power supply (flyback converter), designs the transformer part of a flyback converter, and recommends a straightforward and efficient clamping circuit to enhance it. The controller of the flyback converter is designed in detail. Ultimately, the feasibility and effectiveness of the design method in the driving power supply of unmanned robots are demonstrated by simulation and experiments. [ABSTRACT FROM AUTHOR]

This work presents a modified version of the current-fed dc–dc push–pull converter associated with an active clamping circuit for mitigating voltage spikes on the primary-side switches. Unlike the traditional push–pull topology, saturation due to asymmetrical gating signals applied to the active switches is not likely to occur in the high-frequency transformer because the converter allows for connecting a blocking capacitor in series with the primary winding. In addition, the leakage inductance will not cause high voltage spikes on the primary-side semiconductors owing to the clamping capacitors. Since all active switches operate under the zero-voltage switching (ZVS) condition, one can obtain a high efficiency over a wide load range when comparing the structure with its hard-switching counterpart. Experimental results obtained from a laboratory prototype rated at 1 kW are presented and discussed to validate the theoretical claims. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a single‐ended primary‐inductor converter (SEPIC)‐based DC‐DC converter with higher voltage gain, continuous input current, and lower voltage stress. Suggested converter uses three‐winding coupled inductors and voltage multiplier for boosting function. The proposed structure stores lower amount of energy due to lower current magnitudes of used inductors. Moreover, using voltage multiplier reduces the voltage stress of the elements connected to the output terminals of the proposed converter. By reducing the voltage stress, in addition to reducing the rating of output elements and costs, the overall efficiency will also be increased. Also, a clamping circuit is used to diminish the voltage stresses on power switch. In order to represent the advantages of the proposed converter over some other converters in the viewpoints of the number of the used elements, continuity of input current, voltage gain, the voltage stress on power switch, and output diode, a comparison study is provided. To validate the practicability of the proposed converter, a 200‐W prototype is implemented and the experimental results are provided. [ABSTRACT FROM AUTHOR]

This article presents a novel high gain soft-switching DC–DC converter with low component count and low voltage stress across switching devices. The proposed converter employs coupled inductor and voltage multiplier techniques to achieve high gain at low duty and low turn ratios. An active clamp circuit is also used to reduce voltage stress across the switch. As a result, lower voltage rating switches having lower on-state resistance (Rds-on) are used, lowering system cost. It also helps to achieve zero voltage switching (ZVS) turn-on across both MOSFETs, reducing switching losses and improving efficiency. The leakage energy of the coupled inductor is recycled to improve the voltage gain, and the quasi resonance formed by the leakage inductance and switched capacitors helps to achieve zero current switching (ZCS) across diodes. This also helps in controlling the falling rate of output diode current, helping to mitigate the reverse recovery problem. The steady-state analysis has been carried out. A 500W prototype of the proposed converter is built up and tested to validate the working of the converter. [ABSTRACT FROM AUTHOR]

Traditional phase-shift full-bridge (PSFB) converters have the problems of a narrow zero-voltage switching (ZVS) range, a large circulating current, and voltage oscillation. A PSFB converter with novel auxiliary circuits is proposed to solve these problems for a wide voltage output charging application. A simple passive circuit is connected to the primary tap of a transformer with unbalanced magnetic windings, which can provide two differentiated constant triangular currents for ZVS of the leading and lagging legs in the full-load range. Thus, both the external series large inductance and the duty cycle loss are avoided. In addition, the introduced reactive loss is reduced. Meanwhile, a center tap clamping circuit is added on the secondary side. The leakage inductance of the transformer is fully utilized to resonate with the clamping capacitor. Hence, reductions in the voltage stress of the rectifier diode and circulating current can be achieved. A circuit steady-state analysis of the three modes of the proposed converter is carried out. When compared with the conventional PSFB converter, the proposed converter improves efficiency and reduces the filter requirements. A 100 kHz/1.05 kW prototype is established to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

Summary: This paper proposes a novel active clamp‐based quadratic boost converter to achieve a high gain output voltage. The converter combines a quadratic boost converter with a voltage doubler circuit using a coupled inductor. An active clamp circuit with an auxiliary switch is used to utilize the usually wasted energy of leakage inductance and clamp the voltage to a certain limit. The combination of leakage inductance and parasitic capacitance of the main switch provides the benefit of zero voltage switching (ZVS) in both MOSFETs. Similarly, output diodes operating under zero current switching (ZCS) improve the overall efficiency of the converter. Voltage doubler and active clamp circuitry reduce the voltage stress on solid‐state devices; hence, a low Rds,on device is selected. The converter model is simulated using PSIM software and calculated maximum efficiency of ~95% for 200 W and measured maximum efficiency of ~93% for 190 W power level including various parasitic elements. [ABSTRACT FROM AUTHOR]

This paper proposes new Non-Isolated Interleaved (NII) DC–DC converter for distributed generation system to step-up voltage level of photovoltaic unit. Three winding coupled inductors (TWCIs), voltage tripler rectifier and voltage multiplier are integrated to derive this converter to achieve high step-up voltage gain with lower turns ratio and duty ratio. The key feature of this converter is low voltage stress on switching devices compared to existing TWCIs NII topologies for similar gain. Input side interleaved structure is employed to reduce input current ripple and to increase power density. The proposed converter can transfer energy of Coupled Inductor (CI) to output capacitors in forward and flyback modes, therefore converter can eliminate effect of right-half-plane zero. This converter can achieve high bandwidth and improve dynamic response. Three windings of CI are wound using bifilar and interleaving methods to reduce leakage inductance, therefore lossless passive clamp circuit is sufficient to recover leakage energy of CI. In this paper, operational principles and steady-state analysis of proposed topology is discussed. Small-signal-model of this converter is derived. Performance analysis and operation of proposed topology are verified via experimental results of a 250 W, 24 V input to 350 V output laboratory prototype. Single loop voltage control of this converter is implemented to achieve regulated output voltage and to further enhance dynamic response. [ABSTRACT FROM AUTHOR]

This paper presents a quadratic-type high step-up DC–DC converter for renewable energy applications with a continuous input current. To reduce the number of components while increasing the gain, a quadratic boost converter and two multiplier cells are applied as the primary and secondary circuit with one coupled inductor connected. In addition, the clamp circuit shares its components with both the second boost stage and the voltage multiplier, which increases the power density. As a result, the leakage energy is recycled and the voltage stress can be suppressed. The operation principles and steady-state analyses including loss analysis of the proposed converter are addressed in detail. Compared with relevant existing topologies of quadratic converter, the proposed converter performs a higher voltage gain and a lower power switch stress. To validate the performance, a 200 W experimental prototype is constructed and tested with 20 V of input voltage and 400 V of output voltage, where the highest efficiency is 95.2% and the full-load efficiency is 93.7%. The performance under dynamic conditions is also verified. In the end, an improved topology based on the proposed converter is supplemented. [ABSTRACT FROM AUTHOR]

Integrated gate-commutated thyristors (IGCTs) have successfully demonstrated to be well-suited devices for an application in medium-voltage dc transformers based on LLC resonant converter topology. This appli- cation enables unusually high switching frequencies in kilohertz range thanks to the zero-voltage switching while maintaining the high conversion efficiency. Moreover, the clamp circuit that is an inseparable part of every hard-switched IGCT-based converter can be completely omitted—further lowering the converter complexity and cost. Nevertheless, without the clamp circuit, the effect of shoot through becomes fatal, considering that the IGCTs have a defined mode of failure in short circuit and the desaturation effect is practically nonexistent. To prevent the shoot through, this letter proposes a simple, yet effective, protection method based on anode-voltage measurement that can be implemented locally on the IGCT gate unit. The validity of the solution is demonstrated using a custom IGCT gate unit in a medium-voltage resonant test setup. [ABSTRACT FROM AUTHOR]

Aiming at solving the problem of the low output voltage of fuel cell systems, this paper proposes a new type of high-gain low-ripple passive clamping common ground boost converter, which is based on the research of a traditional switched inductor converter. In addition to greatly improving the voltage gain, it has a number of advantages. (1) The specific structure achieves almost zero input current-ripple and prolongs the service life of fuel cells. (2) The passive clamping circuit solves the problem of the switches voltage resonance caused by inconsistent circuit component parameters, reduces the voltage stress of the switches, and enhances the output voltage gain of the system. (3) The input and output sides share a common ground, which effectively suppresses electromagnetic interference and other issues. In this study, the working principle, steady-state characteristics, comparison study, and component parameter design of the proposed converter are introduced in depth. Finally, the correctness and feasibility of the theoretical research of the proposed converter are validated by experimental results. [ABSTRACT FROM AUTHOR]

The current inverter is the core component of the helicopter transient electromagnetic (HTEM) detection system. It should meet the concerns of low loss, high power, and fast turn-OFF time. This article proposes a new circuit topology based on nine-level inverter technology to overcome the drawbacks of typical PWM (pulse width modulation) inverters, such as switching losses and harmonics. This circuit topology overcomes the shortcomings of the traditional single constant voltage clamp circuit in which the turn-OFF time is not adjustable. Using an inverter with the proposed topology is able to avoid the complex PWM control method and switching loss. In this way, the current rising edge and falling edge of this inverter are also improved effectively. The proposed inverter has adjustable turn-ON-time and turn-OFF time, which is significantly different from the conventional single-clamp inverter. Through subsequent experiments, the inverter proved to have the capability of generating trapezoidal current waveforms. Moreover, by modifying the FPGA (Field Programmable Gate Array) control program, three different turn-OFF times are achieved. The nine-level inverter has a peak current of 1.5 A with an adjustable turn-OFF time from 129 μs to 162 μs. Moreover, the switching frequency of the inverter is reduced from 10 kHz to below 100 Hz. The experimental results further demonstrate that it achieves lower switching losses and more flexible transmission. Our work in this article provides an efficient way to improve the performance of HTEM detection systems. [ABSTRACT FROM AUTHOR]

This article presents a high‐gain soft‐switching DC–DC converter that achieves high gain by using a coupled inductor and a voltage multiplier. An inductor is used to provide a continuous and low‐input current ripple. The voltage stress across the switch is reduced with the help of an active clamp circuit. Hence, lower voltage rating switches having low on‐state resistance Rdson are used to reduce the system cost. It also benefits of zero voltage switching (ZVS) turn on across both the MOSFETs. Thereby, switching losses are reduced, and hence, efficiency is increased. Because of these advantages, it best suits photovoltaic (PV) and DC micro‐grid applications. Since diodes are switched on and off with zero current (ZCS), diode switching losses are reduced, and the reverse recovery problem of diodes is eliminated. The leakage energy of the coupled inductor is recycled to increase the voltage gain. A 500 W prototype is built‐up and tested under various load conditions. The experimental values are in close synchronization with theoretical values. [ABSTRACT FROM AUTHOR]

In this paper, a QR flyback converter using a self-driven active snubber (SDAS) was proposed to solve the problem of voltage surge in the switch of QR flyback converters. In the proposed converter, the SDAS consisting of a clamping capacitor and an active switch can be configured in parallel with the main switch or transformer to reduce the voltage surge in the switch. To confirm the steady-state characteristics of the QR flyback converter to which the proposed SDAS is applied, equivalent circuits for each state were constructed, and the equations and characteristics for each state were determined. A 60 W class small AC–DC adapter was constructed to confirm the effectiveness of the proposed converter and the control circuit method, and the experimental results were analyzed. The size of the experimental AC–DC adapter was 74 × 29 × 23   mm , and it had a high power density of 20   W / in 3 or more. The experimental circuit was limited to the high power conversion efficiency of up to 91.56%, and the maximum voltage surge in the switch was approximately 450 V. One of the reasons for such high efficiency is the SDAS circuit, which sufficiently reduces the voltage surge of the QR flyback switch, compared with the RCD clamp circuit, and does not consume power in principle. [ABSTRACT FROM AUTHOR]

This article introduces a nonisolated, high step-up voltage multiplier cell (VMC)-based dc–dc converter for applications such as module-integrated converter and power optimizers. The VMC combines switched capacitor with autotransformer techniques and active clamp circuit. The autotransformer tertiary winding is employed to increase voltage gain without operating the main switch under extreme duty cycle condition, to reduce the current through the main switch before it turns offand to ensure its zero-voltage switching (ZVS) operation on a wide operation range. The auxiliary switch in the clamp circuit provides ZVS for the main switch and vice-versa. Thus, both switches are turned on with zero voltage and there is no switching loss. Hence, high switching frequency is used to reduce the passive components’ volume and weight. Besides, the low dc-bias and bidirectional magnetizing current allows a smaller magnetizing inductance in the autotransformer to further minimizing the dimensions of the magnetic core. The leakage inductances are used to provide zero-current switching condition for the diodes, eliminating their reverse-recovery losses. The operation principle, steady-state analysis, and design guidelines are depicted and validated through experimental results obtained from a 350-W prototype of the proposed converter. Efficiency of 96.5% at full load is also reported. [ABSTRACT FROM AUTHOR]

Zero-voltage zero-current switching (ZVZCS) phase-shift full-bridge (PSFB) dc–dc converters are candidate converters for high-power switching mode power supply because of their low cost and high efficiency. However, these converters still have some definite weaknesses, e.g., resetting obstacles of high-value currents, extra electrical stress on the power devices. Hence, customers seldom adopt these topologies in high-power applications. This article proposes a new ZVZCS PSFB dc–dc converter to solve the above problems. A clamping circuit with two mosfets, two diodes, and a resetting transformer ensures ZCS of the lagging-leg switches over a wide load range, and no extra electrical stress arises on the primary or secondary components. The clamping circuit has a high current reset ability and can break through the power limitation of conventional ZVZCS PSFB dc–dc converters. The volume of the resetting transformer is small because of the low voltage-second product, and the added mosfets cause low power loss because of the wide soft-switching load range and low on-resistance. The experimental results from a 12-kW prototype prove the rightness and advantages of the proposed converter. [ABSTRACT FROM AUTHOR]

Recently, integrated gate-commutated thyristors (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 exceptionally low conduction losses. The high voltage and current ratings of the IGCTs make them a preferred choice for an efficient bulk power transmission. This article 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. [ABSTRACT FROM AUTHOR]

This paper presents a nonisolated high step‐up soft switching DC/DC converter with continuous input and output energy, low input current ripple, and low voltage stress of semiconductors. In this topology, passive clamping circuits are used not only to recycle leakage energy but also to successfully alleviate voltage spikes on the active MOSFET. The leakage inductor, on the other hand, solves the output diode's reverse recovery problem effectively. Furthermore, output capacitors are connected in series to supply the output load, resulting in a smaller output capacitor volume. The suggested topology's operational theory, as well as steady‐state analyses, is thoroughly explored. The proposed topology's voltage gain and switch stress are then compared with that of some high‐gain topologies. After this, a prototype circuit with a 20 V input voltage, 340 V output voltage, and 200 W output power is designed to test the proposed topology's accuracy. [ABSTRACT FROM AUTHOR]

A novel modulation scheme for a bidirectional isolated pulsewidth modulation active-clamp (PAC)-Ćuk converter is presented in this article. In the PAC-Ćuk converter, the clamping circuit consisting of a capacitor, a series inductor, and an active device enables zero-voltage-switching (ZVS) turn-on capability of all the active devices. This additional circuit equips the converter with three independent control parameters. This article discusses power transfer, ZVS region, and circulating current dependency on the control parameters across the converter gain. Minimal circulating current is generally desired to decrease the conduction losses. With the help of the proposed modulation technique, the optimization of the control parameters to achieve lower circulating current while ensuring ZVS operation is also discussed. A 2-kW experimental converter is also designed and fabricated to validate the analysis. [ABSTRACT FROM AUTHOR]

In this article, a fully soft switched interleaved bidirectional buck/boost converter with high voltage conversion ratio (VCR) and no pulsating current at low voltage source is proposed. Winding cross-coupled inductors technique is employed in order to increase VCR and mitigate current ripple at low voltage side. Moreover, soft switching conditions for all semiconductor devices are provided and the leakage inductances energy of coupled inductors are absorbed in both high step-up/down operating modes. Furthermore, the reverse recovery problem of all diodes is removed due to zero current switching turn off. All the mentioned advantages are achieved for a bidirectional converter with two interleaved phases in both high step-up/down operating modes by only one clamp circuit consisting of a clamp capacitor and two active switches. Also, the body diodes of the main switches are utilized as the main diodes to reduce the element count. The converter performance is validated by theoretical analysis and an 800 W prototype circuit in both operating modes. [ABSTRACT FROM AUTHOR]

This article introduces a novel nonisolated single-switch high step-up DC-DC converter using a tri-winding coupled inductor (TWCL) for renewable energy applications such as PV systems. Also, the voltage multiplier cell (VMC) is used to attain a high voltage gain. The used VMC acts as a passive clamp circuit and reduces the voltage stress across the power switch. So, a low voltage-rated power switch can be used in the presented converter. The suggested topology uses only one power switch with low on-state resistance (RDS-ON), which leads to a simple control circuit and decreases the conduction losses. Highefficiency, operating with low duty cycle, low peak voltage over semiconductor elements, low turns ratio, the number of the coupled inductor, and high voltage conversion ratio are the significant benefits of the recommended DC-DC converter. To show the achievement of the presented structure, operational mode principles, steady-state, efficiency calculations, and comparison results are provided. Finally, a 120 W experimental prototype with 200 V output voltage and 50 kHz switching frequency is built to prove the usefulness of the suggested high step-up converter. The efficiency is measured 92.11% at rated power. [ABSTRACT FROM AUTHOR]

This paper presents a non-isolated single switch converter with high voltage gain. Its circuit topology is combined with coupled-inductor, clamp circuit, and voltage lift capacitor techniques. The proposed converter has several advantages: First, the circuit is controlled by only single pulse width modulation (PWM) for the power switch, which keeps the circuit simple. Secondly, the proposed converter is used as a clamping circuit,which let the energy of the leakage inductance can be circulated to the capacitor, so that the voltage spike on the active switch can be suppressed, and improves efficiency. This paper will introduce the principle of action, theoretical analysis, and experimental waveform in order. Finally, in the case of input voltage of 48 V, output voltage of 400 V, and output power of 1 kW, the performance of the proposed converter is verified. As a result, the maximum efficiency is up to 96.5% and full load efficiency is 92.3%. [ABSTRACT FROM AUTHOR]

This paper proposes a new ultra-high step up converter by employing coupled inductor and interleaved techniques. Winding cross coupled inductors are utilized to enhance the conversion ratio and reduce the voltage stress of semiconductor components. Low voltage stress of switches makes it possible to use low on-resistance power switches. The conversion ratio of the proposed interleaved converter is extended by integrating with voltage lift circuits. The current flows into coupled inductors and the input current ripple is reduced because of the interleaved structure. The spike voltage of the switches is restricted by the clamp circuit. Main specifications of proposed interleaved converter are ultra-high voltage gain, low input current ripple, low voltage stress, low current stress, low core size, small volume, low reverse recovery loss of diodes, low conduction loss and high efficiency. The 18 V to 450 V prototype circuit is implemented at 100 W and its experimental results are presented which ascertains theoretical analysis. [ABSTRACT FROM AUTHOR]

The dc circuit breaker plays an important protection role in the dc distribution systems. Hybrid dc circuit breaker (HCB) offers low conduction losses and reasonably fast response times. In this article, a high power density, modular, and scalable power electronic interrupter (PEI) design is introduced for medium-voltage (MV) HCB platforms. Following this concept, the single low-voltage module is first investigated in terms of the high pulse current ratio and the voltage clamping circuit. After the comparison and test among different devices, a compact module with 1.7-kV discrete IGBTs are selected as main switches. While the voltage clamping circuit is carefully designed to guarantee no tail current bump and sufficient turn-off voltage margin. Next the whole system with series modules is optimized on the aspects of the turn-off strategy, power supply structure, and layout of modules. An improved staged turn-off scheme is proposed, which can not only reduce the peak current and total metal oxide varistor (MOV) energy, but also help balance the MOV energy distribution. A 12-kV and 1-kV breaking capable PEI was demonstrated based on the proposed PEI design, achieving a peak power density of 7.4 kW/cm3, much higher than the IGBT module-based solution. The breaking capability and effectiveness of the modular PEI is demonstrated in a 6-kV MVDC HCB device. [ABSTRACT FROM AUTHOR]

This paper proposes a new Non-Isolated Interleaved (NII) high step-up gain DC-DC converter. This new topology aimed for high power applications, which achieves high step-up voltage gain without a high turns ratio n and a high duty cycle. This converter comprised of two-phase interleaved Coupled-Inductors (CIs) integrated with voltage multiplier rectifier and switched capacitor. The key feature of this converter is very low voltage stress on switching devices compares to existing NII high step-up gain topologies for the similar gain. The reduced rating allows the use of low-voltage rating power devices. Besides, the presented converter inherently recycles the leakage energy, and do not require an auxiliary clamp circuit. In addition, the switching operation is free from the reverse recovery problem due to the zero-current-switching. The working principle and performance characteristics of the converter are presented in detail. The analytical study of effect of parasitic parameters on voltage gain and efficiency of this converter is also presented. The performance comparisons with existing NII high step-up gain topologies are provided to highlight the merits of the converter. To verify the correctness of the theoretical analysis, the experimental setup of 300 W is built. The experiments are conducted to boost 24 V–380 V with turns ratio n = 1, and to boost 24 V–580 V with n = 2. [ABSTRACT FROM AUTHOR]

This paper presents three high voltage gain DC-DC converters based on stacked input and output connection of nonisolated buck-boost converters with coupled inductor and voltage multiplier cells. Besides that, an empirical approach for the coupled inductor winding is proposed to show how to reduce the leakage inductance. In this way, the proposed converter achieves high voltage gain, low voltage, and current stress across the components without using an auxiliary clamp circuit, and they present a low component count. Besides that, this paper presents the evaluation of MPPT, modeling, and control of the converters. To validate the theoretical evaluations, three prototypes were built and evaluated experimentally, considering input power of 200 W, input voltage of 37.4 V, output voltage of 400 V, and switching frequency of 50 kHz. Finally, it should be noted that the maximum efficiency achieved is 97.53% at nominal input power. [ABSTRACT FROM AUTHOR]

Pulse test techniques are widely adopted in characterizing both the static and dynamic performances of semiconductor devices considering various device structures and operating conditions. For gallium nitride (GaN) devices, due to the current collapse phenomenon, fast and accurate measurement of their key electrical parameters, such as dynamic ON-state resistance ${R}_{\text {ds}, \mathrm{\scriptscriptstyle ON}}$ , switching rising time, fall time, switching losses, and short-circuit (SC) robustness, becomes essential. This article presents a comprehensive review of state-of-the-art pulse test setup methods such as the double-pulse test (DPT), multiple-pulse test (MPT), and SC test (SCT) for the first time, which facilitates the GaN device structure design and practical applications in high efficiency and power density power converters. [ABSTRACT FROM AUTHOR]

This paper presents a nonisolated ultrahigh step-up DC-DC converter with an interleaved structure that is suitable for high power and voltage applications. In order to increase the voltage gain, the proposed structure uses coupled inductors and switched-capacitor cells. Achieving this goal is accompanied by avoiding the imposition of any extreme duty cycle or high turns ratio to the converter. The current ripple is reduced due to the use of the interleaved structure. Since the voltage stress of the switches is lower than the output voltage, by selecting the low-voltage rated switches and small RDS(on), the conduction losses are reduced. In addition, alleviating the phenomenon of reverse recovery of diodes and creating soft-switching conditions in MOSFETs, which leads to a reduction of switching losses, are other advantages of the proposed converter. Therefore, there is no need to use clamp circuits in the mentioned structure. The experimental results, using a prototype of 350 W-18 V/400 V, verify the effective performance of the proposed converter. [ABSTRACT FROM AUTHOR]

A high step-up coupled-inductor single-ended primary-inductor converter (SEPIC) DC–DC converter with input current ripple cancellation is presented in this study. The proposed converter is based on the structure of a SEPIC but also has a coupled inductor. In the proposed converter, two coupled inductors are used to increase the voltage gain and remove the input current ripple. The voltages of the main switch and all diodes are clamped to prevent high-voltage surges caused by the leakage inductance of the coupled inductor. Hence, a dissipative snubber circuit or an active clamping circuit is not required. As a result of the reduction of voltage stress, a MOSFET with low drain-to-source on-state resistance RDS(ON) can be used as the main switch. To demonstrate the performance of the proposed converter, a prototype converter with an input voltage of 24 V, an output voltage of 300 V, and output power of 100 W is implemented. [ABSTRACT FROM AUTHOR]

In this paper, a new non-isolated DC-DC converter is proposed. This converter topology is a high step-up boost converter with an extended voltage multiplier cell and a Cuk converter as a series output module. Compared to its high step-up counterpart, the proposed converter has a higher voltage gain. In this converter, an active clamp circuit is used to absorb the energy of leakage inductor, therefore, the ZVS turn on/off for switches and ZCS for diodes are achieved. The voltage stresses on the switches are low, and the reverse-recovery problem of the diodes is eliminated. The operational principle and characteristics of the proposed converter are presented. The analytical and simulated results are validated using a 200 W prototype converter with 20 V input and 400 V output operating at 100 kH. [ABSTRACT FROM AUTHOR]

This study presents a new high step-up converter based on the voltage multiplier cell and coupled inductor for renewable energy applications such as fuel cell and photovoltaic power systems. This converter achieves a high voltage conversion ratio using a coupled inductor and voltage multiplier cell (VMC). The voltage multiplier cell acts as a passive clamp circuit and reduces the maximum voltage across the power switch. The suggested topology has only one power switch in its structure, which leads to low cost and volume. The other benefits of the proposed structure are low components count, low input current ripple, low voltage stress throughout the semiconductors, high efficiency, zero-current switching (ZCS), and zero-voltage switching (ZVS) of diodes. Besides, due to the soft-switching condition of the diodes, the reverse recovery problem can be decreased. To show the effectiveness of the suggested topology, operation survey, steady-state analysis, and efficiency calculation are provided. Additionally, the comparison study with other similar converters illustrates the superiority of the proposed structure. Finally, an experimental prototype with 150 W rated power, 50 kHz switching frequency, and 24 V input voltage is implemented to prove the mathematical analysis and effectiveness of the proposed DC-DC converter. [ABSTRACT FROM AUTHOR]

This article presents a novel design of a bipolar current-pulsed power supply (BCPPS) for shallow electromagnetic detection. Problems of acquiring current pulses with low oscillation and low energy cost are analyzed in detail and relevant solutions are given. An improved topology based on a constant-voltage clamping circuit is proposed to satisfy the demands of supplying the highly inductive load. The relationship between the main steady-state parameters of the proposed BCPPS is provided and the shape of current pulses can be adjusted flexibly by changing the duty cycles of the switching signals in the topology. A feedforward control strategy to realize constant-current transmitting is proposed and the digital controller is designed. Compared with different existing current-pulsed sources, the topology in this article is characterized by high repeat frequency, low energy cost, and low switching interference. A laboratory prototype with a maximum peak current of 50 A and repeat frequency of 500 Hz is built to verify the effectiveness of the proposed topology. [ABSTRACT FROM AUTHOR]

In this article, a novel single-switch, high step-up dc–dc converter based on three-winding coupled inductor and voltage multiplier circuit (VMC) is proposed. And on this basis, pump capacitor unit (PCU) is integrated to achieve a very high voltage gain. The converter makes full use of the advantages of three-winding coupled inductor, skillfully combines it with the VMC, and integrates the PCU that can be used in superposition to further improve the voltage gain. The voltage stress of the switch is reduced by using a passive clamping circuit to recycle the leakage energy of the coupled inductor. The operating principle and steady-state analysis of the presented converter in continuous conduction mode are introduced in detail. Moreover, the comparative analysis shows that under the same conditions, the proposed converter has higher voltage gain and lower voltage stress than others. Several advantages include high voltage gain, low voltage stress, low turns ratio of coupled inductor, and high conversion efficiency, make the proposed converter very suitable for new energy generation applications, such as photovoltaic systems. Finally, the feasibility of the proposed converter and the correctness of theoretical analysis are verified by a 500-W prototype at 50 kHz switching frequency. [ABSTRACT FROM AUTHOR]

This article presents a high gain pure sine- wave inverter based on the full-bridge dc–ac high-frequency link cycloconverter topology for telecom or general-purpose applications. The improved quasi-resonant modulation method allows reduction of ringing and turn-off losses of the dc-side switches. This is achieved with minimal energy circulation and requires no multi-mode operation or extra auxiliary clamping circuits. The soft switching can be provided even if relatively large lossless snubber capacitors are connected across the input side transistors. Moreover, two of the switches at the ac side operate at fundamental frequency, while the rest feature zero current turn-off. A 48 VDC to 230 VAC, 1.2 kW sine-wave inverter prototype was developed to verify the proposed concept. [ABSTRACT FROM AUTHOR]

This article introduces a new nonisolated full soft-switching step-up dc/dc converter based on single-ended primary inductor converter (SEPIC) structure. The proposed topology utilizes a three-winding coupled-inductor (TWCI) to increase the voltage gain, but unlike other coupled-inductor-based converters, its voltage gain is increased by reducing its magnetic turns ratio. Moreover, the secondary and tertiary turns ratios of the TWCI can be used as an additional design freedom to extend the voltage gain, which indicates more converter flexibility. Due to the continuous input current, the proposed converter can be used for many types of renewable energy sources. Also, the leakage energy from the TWCI has further been recycled and transferred to the output with the help of a regenerative passive clamp circuit. Due to the soft-switching performance, the proposed converter has no switching losses at the turn-on instant for the power switch and reverse recycling losses of the diodes. Furthermore, the use of a small number of components along with the soft-switching performance offer high efficiency. Steady-state analysis and design considerations are discussed thoroughly. Finally, a 200-W prototype with 200 V output voltage is provided to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

Immersion of an elastic cantilevered sheet in a fluid can strongly affect its dynamic response. While significant effort has been expended in studying slender cantilevered sheets, the behavior of wide sheets has received far less attention. Here we study the clamping configuration's effect on the vibrational dynamics of wide cantilever sheets of macroscopic size, which naturally generate inviscid flows. Three practically relevant clamping configurations are investigated: clamping into (i) a thin and rigid horizontal plate, (ii) a rigid vertical wall, and (iii) a rigid line. These are found to produce different resonant frequencies, as expected from the nonlocal flows generated by these cantilevers. The resulting formulas are joined to an existing expression for slender cantilevers, leading to a universal formula valid for all aspect ratios (cantilever length/width) and mode numbers; accuracy is verified using finite element analysis. This study is expected to be of practical value in a host of engineering applications, such as those that utilize fluid-structure interactions for energy harvesting and aerodynamic design. [ABSTRACT FROM AUTHOR]

In this article, an interleaved high-voltage gain dc–dc converter is proposed for use with photovoltaic (PV) systems. By integrating two three-winding coupled inductors (CIs) with switched capacitor cells, the voltage gain is further extended. Through passive diode-capacitor clamp circuits, the energy stored in the leakage inductances is absorbed; additionally, the voltage stress of the power switches is clamped to a value far lower than the output voltage, which enables designers to select switches with low-voltage ratings. Due to the interleaved structure of the proposed converter, the input current has a small ripple, which leads to the increased lifespan of the PV panels. In addition, the current stress on the components is reduced. Thanks to the leakage inductances of the CIs, the zero-current switching condition is intrinsically provided for the diodes; accordingly, the adverse impact of the diodes’ reverse-recovery is alleviated. The operating principles, steady-state analyses, and design considerations of the proposed converter are presented in this article. A comparison with other similar converters is carried out to verify the merits of the proposed converter. Finally, the theoretical analyses are confirmed through the experimental results of a 400-W prototype with an output voltage of 400 V. [ABSTRACT FROM AUTHOR]

In this article, a novel dc–dc light-emitting diode driver employing an interleaved converter is proposed and analyzed. The circuit topology mainly consists of two parallel buck–boost converters. A coupled inductor, which is composed of a magnetic core and two windings, is used to replace the energy storage inductors of the two buck–boost converters. This not only does not add any components, but also saves a magnetic core. The buck–boost converters are designed to operate near boundary conduction mode. Due to the characteristics of magnetic flux balance, the magnetic-excited current can be converted between the windings of the coupled inductor. By using the magnetic-excited current to release the charge stored in the parasitic capacitors of the active switches, these switches can fulfill zero-voltage switching on (ZVS) without the use of any auxiliary switches, active clamping circuits, or snubber circuits. Moreover, the freewheel diodes of both buck–boost converters can achieve zero-current switching off (ZCS). The steady-state analyses for different operation modes are provided, and the mathematical equations for designing circuit components are conducted. Finally, a 200-W prototype circuit was built and tested to verify the analytical predictions. According to the experimental results, all the semiconductor devices are operated at either ZVS or ZCS, and the circuit efficiency as high as 95.0% is measured. Satisfactory performance has verified the feasibility of the proposed converter. [ABSTRACT FROM AUTHOR]

In this article, a novel isolated circuit breaker (ISCB) that realizes robust interruption capability is proposed for direct current microgird protection. First, the proposed ISCB isolates the main current path and the commutating circuit during the fault-clearing state, thereby not causing fault current surges on both the input and output sides, and effectively protecting the source and load. Second, the ISCB can automatically charge the commutating capacitor to offer interruption capability before the reclosing of the breaker, which ensures a safe restart of microgrids after faults (especially temporary faults). Third, due to the introduced voltage clamping circuits, the ISCB can successfully interrupt faults without being effected by parasitic parameters on microgrids. Finally, the use of the insulated gate triggered thyristor with strong tolerance to current and voltage surges can also enhance the robustness of the ISCB. Consequently, the ISCB features higher fault interruption robustness than the existing breakers. Moreover, design guidelines are provided through mathematical modeling, and then based on the design guidelines, a laboratory prototype is developed to validate the feasibility of the ISCB. [ABSTRACT FROM AUTHOR]

This paper presents an isolated single-stage on-board electric vehicle charger without an intermediate DC-link. Based on an isolated current-source topology, the converter features soft-switching in semiconductors regardless of load variation for the full AC line voltage range. Moreover, it requires no external snubber or clamp circuits. The power factor correction and voltage regulation are provided by a relatively simple phase shift modulation, while the amount of circulating energy is kept at minimum. The charger is distinguished by its efficiency characteristic – the maximum is achieved in the constant power charging mode. The control method, component stresses, and design constraints of the topology are analyzed. The concept is verified using a 3 kW experimental SiC-based prototype, which reaches a peak efficiency of 96.4%. Moreover, the charger has demonstrated efficiencies above 95% with the THD of 4.1% when operating in constant power mode at the maximal power. [ABSTRACT FROM AUTHOR]

A high step-up dc–dc converter with multiple magnetic devices and switched-capacitor voltage multiplier cell (SC VMC) is proposed in this article. By simultaneous implementation of a coupled inductor (CI) and a built-in transformer (BIT), the voltage gain is flexibly increased with an additional degree of freedom in comparison with the converters with only BIT or CI. To further increase the voltage gain, the secondary winding of the CI is inserted in series with the primary winding of the BIT. This new architecture leads to multiplication of the turns ratios of the CI and BIT in the voltage gain expression, as well. The SC VMC not only extends the voltage gain but also reduces the voltage stress across the MOSFETs. To have a better device utilization, the blocking capacitor is participated in voltage gain improvement. Moreover, through active clamp circuit, the leakage energy of the magnetic devices is recycled and zero voltage switching (ZVS) performance is obtained for the main and auxiliary MOSFETs. In such a case, the switching frequency can be increased to reduce the volume of the converter. Finally, a 400-W laboratory prototype with 25– 400 V voltage conversion is fabricated to demonstrate the effectiveness of the proposed converter. [ABSTRACT FROM AUTHOR]