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Summary: This paper proposes a zero‐input‐current‐ripple (ZICR) high‐voltage‐gain dc‐dc converter with an integrated Y‐source network. It achieves zero input current ripple by introducing a parallel branch of an extra inductor, a coupled winding, and a capacitor at the input port. The voltage of the added inductor is opposite to that of the coupled winding. By adding the Y‐source coupled inductor, the boost capability of the converter is improved. The unique boost circuit structure makes that one winding in the three‐winding coupling inductance is step‐down type (the turns ratio n2 < 1) while the other winding is step‐up type (the turns ratio n1 > 1). In such a case, high voltage gain can be obtained under a lower turn ratio of the coupled inductor. The inherent passive clamping circuit clamps the spike voltage noises of the main switch to a low level and improves the efficiency. All the diodes have achieved ZCS (zero current switching) turn‐off. By comparing with several new converters, the advantages of this converter are proved. Finally, a 200‐W, 48‐ to 380‐V, 50‐kHz experimental prototype is built based on the theoretical research. At the rated power, the measured efficiencies with and without ZICR are 95.2% and 95.6%, respectively. [ABSTRACT FROM AUTHOR]

High-voltage and high-frequency stresses comprising of AC and DC components are encountered across the surge arresters at various nodes in HVDC stations. There is a need to generate these stresses to evaluate surge arresters employed at different locations in the HVDC networks. In the present work, an attempt is made to develop complex waveforms using a novel single-stage DC–AC converter. The presented switched-mode converter is based on a coupled inductor which gives an extra degree of freedom to obtain a higher gain with the modulation in the duty ratio. Fixing the turns ratio of the coupled inductor, the duty ratio is appropriately modulated to generate the complex waveform of high frequency and high amplitude. The proposed converter offers a single-stage solution for DC–AC inversion using pulse width modulation, with fewer components, higher power density, and the ability to generate a frequency of 600 Hz. The detailed converter and controller design analysis is discussed in the present investigation. The breakdown operation of the surge arrester demands a massive short-circuit current from the source side, which may be difficult to obtain if a high-gain amplifier is used without proper protection. The presented switched-mode converter-based approach rectifies the issue of the short-circuit current during the insulator breakdown. A simulation study is performed to validate the circuit for both positive and negative buck-boost regions. Further, a hardware setup is developed to verify the generation of high-frequency and high-voltage complex waveforms. The developed converter could be widely used for insulation evaluation and condition monitoring of various high-voltage equipment. [ABSTRACT FROM AUTHOR]

This paper proposes a novel zero-voltage zero-current transition (ZV-ZCT) DC/DC high gain coupled inductor based boost converter for applications in renewable energy systems. It employs an auxiliary resonant network to soft-switch transition of semiconductor switches and soft-recovery of power diodes over wide input voltage and output power range of the converter with high efficiency. The auxiliary cell of the proposed converter has negligible impact on the converter's overall dynamics and it doesn't contribute any extra current stress to the semiconductor switches compared to classical hard switched boost converters. A thorough theoretical analysis of each operating mode has been presented together with the converter's steady-state performance. The mathematical equations illustrating the dynamic behaviour of the converter have been used to design the auxiliary cell components. The circulating current loss has been minimized and simultaneously soft-switched operation of the converter is maintained through optimal selection of auxiliary cell components. Additionally, a power loss study and the proposed converter's advantages over existing traditional converters are discussed. The converter's soft-switching behaviour is established by hardware testing on a 400 W, 100 kHz prototype model. The theoretically predicted behaviour of the converter has been well corroborated by experimental observations. [ABSTRACT FROM AUTHOR]

Bipolar dc distribution system is an attractive alternative to replace the conventional ac distribution system; however, it suffers from voltage and current unbalances. In parallel-connected triple-active-bridge (TAB) converters that form a bipolar dc distribution system, the current unbalance between each TAB module and the voltage unbalance between each load are the main issues that make controlling the system difficult. These unbalances occur due to the inevitable mismatch of gate signals and circuit parameters, despite having the same circuit components. A four-winding coupled inductor is proposed in this paper to handle these issues. The coupled inductor is formed by the magnetic integration of the inductors, which are present in TAB converters. Inductors in the same TAB module are directly coupled and the two directly coupled inductors are integrated again in the inverse direction. The proposed coupled inductor automatically balances the currents in each module and the voltages of each load under unbalanced conditions. Moreover, the proposed balancing scheme does not require additional control method or balancer circuit. The performance of the proposed coupled inductor was verified with a 10-kW prototype. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of a high voltage gain converter utilizing a coupled inductor with reduced voltage stress, specifically for photovoltaic energy-based systems. The proposed converter employs a two-winding coupled inductor and voltage multiplier cells to achieve an increase in output voltage while mitigating voltage stress across semiconductor components. Additionally, the voltage multiplier cells function as voltage clamps for the power switch, further enhancing the converter's performance. The converter features a single switch design, which simplifies control, reduces cost, and improves reliability. Key advantages of the converter include a low component count, a common ground between input and output ports, and high efficiency. The converter's performance is thoroughly investigated through mode analysis and steady-state analysis. Comparative evaluations with similar converters are conducted to highlight the benefits and performance of the proposed design. To validate the theoretical analysis, a 125 W prototype with 26 V input and 200 V output voltages operating at a 50 kHz switching frequency is developed, and experimental results are presented, demonstrating the effectiveness and practicality of the proposed high voltage gain converter. [ABSTRACT FROM AUTHOR]

This paper introduces a coupled inductor (CI)‐based high step‐up DC‐DC converter. Cascaded or quadratic DC–DC converters are the most practical solution to achieve a wide conversion ratio and reduced current ripple. The proposed structure (P1) is achieved by a combination of a base structure of two‐stage boost converter with one active switch, a CI, and a voltage multiplier cell (VMC). The secondary side of the CI is placed at the output side, where it is combined with a VMC. In the proposed topology, a passive clamp consisting of a diode and a capacitor is added to minimize the voltage stress on the active switch. In addition, the passive clamp recycles the leakage energy of the CI and causes to increase the efficiency. The input source current ripple is low, and the input current is continuous, which are very suitable for renewable energy applications. Additionally, the voltage stresses on switches are less than some quadratic DC‐DC boost converters that have been presented. Also, an extended topology of P1 is proposed as the second proposed converter (P2), to enhance the operation of P1. Moreover, to show the feasibility and performance of the presented converter, a laboratory prototype circuit is examined. The results accredit the theoretical analysis and experimental outcomes of the presented converter. [ABSTRACT FROM AUTHOR]

Abstract This paper presents the design and analysis of a high voltage gain converter utilizing a coupled inductor with reduced voltage stress, specifically for photovoltaic energy-based systems. The proposed converter employs a two-winding coupled inductor and voltage multiplier cells to achieve an increase in output voltage while mitigating voltage stress across semiconductor components. Additionally, the voltage multiplier cells function as voltage clamps for the power switch, further enhancing the converter's performance. The converter features a single switch design, which simplifies control, reduces cost, and improves reliability. Key advantages of the converter include a low component count, a common ground between input and output ports, and high efficiency. The converter's performance is thoroughly investigated through mode analysis and steady-state analysis. Comparative evaluations with similar converters are conducted to highlight the benefits and performance of the proposed design. To validate the theoretical analysis, a 125 W prototype with 26 V input and 200 V output voltages operating at a 50 kHz switching frequency is developed, and experimental results are presented, demonstrating the effectiveness and practicality of the proposed high voltage gain converter.

— In this paper, a single switch transformer-less DC-DC converter with continuous input current for photovoltaic applications is proposed. The suggested configuration utilizes a CL1C2D2 structure to achieve a high voltage gain and alleviate voltage pressure on the semiconductor components. This design enables a significant increase in voltage output with a minimal turns ratio, leading to reduced size, weight, and cost of the converter system. The reduction in turns ratio of the coupled inductor results in lowered voltage stress on the semiconductor elements. Additionally, employing just one power switch in the converter simplifies control and reduces expenses. With its continuous input current, this converter is particularly well-suited for integration in photovoltaic systems. Simulation results conducted using PSCAD/EMTDC software validate the efficacy of the proposed power converter. Furthermore, the maximum power output of the photovoltaic module through an MPPT (Maximum Power Point Tracking) controller under varying irradiance levels is determined, and simulations are executed using PSCAD/EMTDC.

Abstract In this paper, a single stage buck–boost DC–AC converter based on coupled inductors is presented for renewable energy and electric vehicle applications. The proposed topology works with only three semiconductor switches, two diodes, and three coupled inductors to transfer input DC voltage to a high gain or low gain output AC voltage. A coupled inductor is used instead of normal inductors, which will reduce core and size requirements. The sinusoidal pulse width modulation strategy is used in this paper for controlling the main switch. There are many merits in the presented topology, like high gain up to five times of input voltage, compact size, less number of components, which results in reducing the overall cost, reducing switching loss, and increasing the converter efficiency. The simulation study is carried out using MATLAB/SIMULINK to simulate the operation of the proposed converter. Also, an experimental setup is built up to examine the actual operation of the proposed converter. There is a good agreement between simulation and experimental results which increases the validation and confidence of the model.

Abstract This paper proposes a new high step‐up DC–DC converter with zero input current ripple for renewable energy sources applications, such as fuel cells. In this topology, a coupled inductor and a multiplier cell are used to achieve high voltage gains. The power switch in this proposed circuit turns on under zero voltage switching conditions. An active switch limits the maximum voltage stress across the main power switch. Moreover, all circuit diodes of the converter turn off without a reverse recovery problem. A detailed analysis of a high‐gain step‐up DC–DC converter is studied along with improved efficiency. The ripple cancellation of the input stage of the converter is done by adding an input inductor and capacitor. By including the parasitic elements, an approximate loss analysis was performed in PSIM and found the maximum efficiency of ∼96% in simulation and ∼94% in hardware for 200 W power level design for 30 V input voltage. Later on, the converter laboratory hardware prototype can be developed with selected parameters, and finally, experimental results have been used to validate the properties of the converter.

Summary: This paper introduces a new non‐isolated double‐input triple‐output (DITO) high voltage gain DC–DC converter with a wide range of applications, including hybrid voltage source systems, solar home appliances, DC‐bus power distribution systems, and electrical vehicles (EVs). The proposed DITO converter interfaces two hybrid voltage sources to supply three different output loads with varying voltage and power levels. Compared to conventional converters of the same type, the proposed DITO converter offers several advantages, including operation for all duty cycles, integration of hybrid energy sources to transfer power to multiple loads, high voltage conversion ratio for all three‐output ports, a higher ratio of total voltage gain to total components number, common grounded input and output DC ports, simultaneous DC voltage regulation of three‐output ports by tuning separate controlling parameters of duty cycles, an additional turns ratio of coupled inductors to increase the voltage gain of output ports, and medium voltage stress on switches. The proposed DITO converter utilizes a new single‐switch single‐coupled‐inductor DC–DC structure, which is analyzed and verified through a prototype implementation for 25 and 30 V input voltages and 210, 330, and 400 V output voltages with a total power of 480 W. The experimental results confirm the simulation results and theoretical analysis. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a novel single-phase non-isolated bidirectional buck converter topology. The proposed converter uses a basic switching cell structure with a coupled inductor and an interleaving switching scheme. This article addresses a crucial challenge in bidirectional DC-DC conversion by prioritizing reducing output current ripples and minimizing filter inductor size. The employed method includes using MOSFETs with fast recovery diodes to mitigate reverse recovery and body diode losses. Furthermore, the optimization of the switching frequency of the output inductor to be twice the actual switching frequency contributes to reducing the component size of the converter. The coupled inductor also helps to reduce stress on components by distributing currents among its legs. The experimental result demonstrates the proposed converter has a very low ripple current as compared to the conventional converter. The low current ripples and smaller filter inductor size enabled by high-frequency operation have improved the efficiency and size of the converter. A common ground between input and output terminals ensures robust performance without common mode current concerns. Overall, the proposed converter represents a significant improvement in DC-DC converters, promising enhanced efficiency, reliability, and compactness in bidirectional DC-DC conversion systems. In order to verify the performance of the proposed converter, a 460 W buck converter prototype was built and tested. [ABSTRACT FROM AUTHOR]

The dc–dc converter plays a vital role in renewable energy power generation systems. To enhance the boost range and supply stable output voltage for the power grid, This paper propose an improved low‐stress ultrahigh‐gain dc–dc converter. First, a voltage multiplier cell is designed stemming from a three‐winding coupled inductor and a switched capacitor (SC), which can obtain ultrahigh voltage gain. In the improved voltage multiplier cell, the number of semiconductor devices is reduced, resulting in a decrease in capacitor voltage stress. Moreover, a passive clamp circuit uses the new SC, which can suppress oscillation peak voltage and absorb the leakage energy of the coupled winding. Furthermore, we deduce the operating mode of the proposed converter . Compared with other advanced topologies, the proposed topology outperforms boosting capacity, component stress, and efficiency. To stabilize the output voltage, the converter is closed‐loop controlled. Finally, experiments on the 180 W prototype have demonstrated the reliability and effectiveness of the proposed topology. [ABSTRACT FROM AUTHOR]

Summary: In this paper, an isolated high efficiency, high step‐down DC–DC converter for ultracapacitor charger applications is presented. In the proposed converter, by utilizing the structure of asymmetrical half‐bridge that combined the current‐doubler synchronous rectifier and the technique of coupled inductors to achieve high step‐down. The step‐down conversion ratio of the proposed converter can be increased by decreasing the turns ratios of transformer and coupled inductors. In contrast to the conventional full‐bridge or half‐bridge converter, the proposed converter can operate in a high step‐down situation; the extreme low duty and turns ratios are not necessary. The theoretical results are verified by experimental results, in the case of 380 V input voltage and 14.6 V output voltage with rated power 1 kW. In addition, the 250F ultracapacitor charged by prototype of the proposed converter from 0 to 14.6 V in 1 min verified its feasibility. [ABSTRACT FROM AUTHOR]

This paper proposes a new high step‐up DC–DC converter with zero input current ripple for renewable energy sources applications, such as fuel cells. In this topology, a coupled inductor and a multiplier cell are used to achieve high voltage gains. The power switch in this proposed circuit turns on under zero voltage switching conditions. An active switch limits the maximum voltage stress across the main power switch. Moreover, all circuit diodes of the converter turn off without a reverse recovery problem. A detailed analysis of a high‐gain step‐up DC–DC converter is studied along with improved efficiency. The ripple cancellation of the input stage of the converter is done by adding an input inductor and capacitor. By including the parasitic elements, an approximate loss analysis was performed in PSIM and found the maximum efficiency of ∼96% in simulation and ∼94% in hardware for 200 W power level design for 30 V input voltage. Later on, the converter laboratory hardware prototype can be developed with selected parameters, and finally, experimental results have been used to validate the properties of the converter. [ABSTRACT FROM AUTHOR]

In this article, the coupled inductor is designed using a litz wire, an enameled litz wire, and a solid wire separately. All the coupled inductors wound with litz and solid wires are tested in a Cuk converter operated in DCM with a 25 kHz switching frequency for 15 W power, and winding losses of each wire, including proximity and skin effect loss, are calculated analytically without using any software, by using different techniques presented in literature, and the results are compared. Also, state-space modeling of the converter using a coupled inductor for DCM is derived as a contribution of the article because such a modeling is not derived for the Cuk converter in the literature. Thanks to the applications, inductor currents, switch voltage, input–output voltage, and output current are measured for coupled inductors with different wires. In addition, FEM simulation and co-simulation of all coupled inductors are realized, and the results obtained by applications are verified by them. Besides, it is shown that while the number of turns is the same, increasing the bundle of wires increases efficiency and inductance, reducing the window area and coupling coefficient. [ABSTRACT FROM AUTHOR]

Summary A high conversion gain, isolated bidirectional converter for energy storage system is presented. Two coupled inductors stored energy and reduced the current ripple in low‐voltage side. Two coupled inductors are combined with the transformer can increase the voltage conversion ratio and achieve galvanic isolation. Additionally, the energy of the leakage inductance can be recycled into an active clamp capacitor to reduce voltage spikes on the switches. In the high‐voltage side, a voltage‐doubler circuit is used to extend the voltage gain. Finally, the prototype circuit 24 V on the low‐voltage side, 400 V on the high‐voltage side and a rated power of 1 kW is implemented to verify the feasibility of the proposed topology. The experimental results show that the maximum efficiencies in the step‐up and step‐down modes are 97.29% and 96.1% respectively, and the measured full‐load efficiencies are, respectively, 96.62% and 95.68%. [ABSTRACT FROM AUTHOR]

With rapid development of high voltage direct current (HVDC) grids, hybrid circuit breakers (HCBs) have gained more attentions, due to their great ability for fault current interruption in HVDC grids. This paper proposes a novel low-cost HCB based on the coupled inductor, to be utilized in HVDC applications. To realize high current breaking capability with low cost, a coupled inductor in combination with the bridge-type circuit is utilized in the breaker branch. The bridge-type circuit is constructed by the series connection of a not pre-charged capacitor, thyristor, and diodes to provide bidirectional breaking ability. After an interruption, the capacitor in the breaker branch can be discharged quickly to guarantee that the proposed HCB is available for the next interruption. Detailed analysis and design equations are also provided to describe the operation of proposed HCB. The proposed HCB is simulated in Matlab/Simulink and simulations are used to analyze the performance of the HCB under the different conditions. Moreover, the proposed DCCB topology is validated using prototype experiments. [ABSTRACT FROM AUTHOR]

A decoupled model predictive control (MPC) power balancing strategy for a coupled inductor-based flying capacitor DC–DC converter (FCDC) is a proposed to solve the power imbalance caused by the parameter differences in the coupled inductor. The decoupled mathematical model of coupled inductor FCDC is firstly derived by analyzing the converter operation state under various modes. On this basis, the control relationship between inductor current and flying capacitor (FC) voltage is redefined and an MPC power balance strategy based on the inductor current with single-step optimization is proposed. The proposed MPC strategy not only achieves decoupled power balancing control but also solves multi-objective dynamic optimization control of the inductor current and FC voltage, greatly reducing the computation load. A detailed theoretical analysis of the proposed strategy is presented and the balancing performance is effectively verified through the experiments. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary In this paper, a new coupled inductor Z‐source inverter is proposed. The proposed topology can increase the boost factor value by increasing the number of turns ratio values. The proposed inverter is completely analyzed, and the related equations to the voltage and current of the used elements and boost factor are obtained. In addition, the values of the capacitors and inductors are designed to have a better performance based on the considered boost factor and input voltage level. Following, the proposed inverter is compared with several related topologies to determine the advantages and disadvantages of the proposed inverter. Finally, the accuracy performance of the proposed inverter is verified through results on experimental prototype. [ABSTRACT FROM AUTHOR]

Many applications, such as photovoltaic systems, uninterruptible power supplies, and automobile headlamps, need a high step-up DC–DC converter without isolation. The conventional boost converter has the advantages of simple topology and easy control. However, it has some shortcomings, such as insufficient step-up voltage ratio and poor efficiency when operating at large duty-cycle conditions. One of the popular topologies used to overcome these problems is the coupled-inductor boost converter. It utilizes the turn ratio of the coupled inductor to realize a higher step-up voltage ratio. The drawback is that the leakage inductance of the coupled inductor causes a huge voltage spike when the power switches are turned off. Moreover, because coupled inductors are characterized by their large volume and high profile, a conventional coupled-inductor boost converter is unsuited for photovoltaic systems, such as the solar microinverter. This study proposes a novel high-step-up boost converter to solve these problems. This proposed converter uses dual coupled inductors instead of the conventional coupled-inductor boost converter. The secondary side of the coupled inductor is connected in series to increase the step-up voltage ratio. The proposed converter utilizes active clamping to achieve zero-voltage switching (ZVS) for suppressing voltage spike and improving conversion efficiency. In addition, low-profile designs can be fulfilled easily for solar microinverters. The proposed converter and its control method are introduced. The operation principle, circuit characteristics, and circuit analysis are presented. A prototype converter with 300 W output power 25–40 VDC input voltage and 200 VDC output voltage was tested. All functions, including high step-up voltage ratio, ZVS, and active clamping, were achieved, and the highest efficiency was around at 94.7%. [ABSTRACT FROM AUTHOR]

Copyright of Electric Power Automation Equipment / Dianli Zidonghua Shebei is the property of Electric Power Automation Equipment Press and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

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]

Summary: Multi‐output converters have been accepted in many portable and display applications due to their ability to optimize hardware both in terms of number of switches as well as on the inductances. Many of these applications require the input voltage to be both stepped up and stepped down, and some applications also require negative outputs. This paper proposes a non‐isolated converter topology which can generate positive buck and boost outputs and also a negative output using a coupled inductor. The converter can operate in continuous and discontinuous conduction modes (DCMs). A detailed analysis of the converter is done in both modes, and it is shown that the outputs can be controlled by direct real‐time analytical estimation of the duty cycle in DCM. Coupled inductor enables the possibility that more than one output can be simultaneously supplied, reducing the cycle time and increasing throughput. Independent control of all three outputs confirms that cross‐regulation is avoided due to real‐time continuous estimation of the duty cycles. The proposed converter is verified by building a hardware model for multi‐output voltages of 5, 24, and −5 V with an input voltage of 12 V using a Spartan‐6 FPGA controller. Experimental results validate that 94% converter efficiency and regulated output voltages under full load conditions. Steady state and dynamic performance of the converter illustrate the effect of suggested control technique to alleviate cross‐regulation in multi‐output converters. [ABSTRACT FROM AUTHOR]

To solve the problem that the output voltage of the new energy power generation device varied greatly and it was difficult to realize energy storage, a novel single-switch coupled buck-boost converter based on PI controller and feed-forward control was presented. The voltage gain could be adjusted by the turns ratio of the coupled inductor, and the voltage stress on the power switch was suppressed by the passive clamped circuit with recycled leakage inductor energy. Compared with traditional buck-boost converter, the proposed converter had the advantages of wider voltage conversion ratio, continuous input current, and low voltage stress on power switch. Combing PI controller with feedforward control strategy, superior input transient response of the converter during the whole input volt age range is obtained. The operating principles and steady-state characteristics of proposed converter were analyzed and derived in detail, respectively, and the performances were compared with other single-tube buck-boost converters. The small-signal model was derived, and the correctness of PI parameter design was verified by bode diagram. The design process of PI controller combined with feedforward control strategy was analyzed. Finally, an experimental prototype with a rated power of 100 W, 20 V to 60 V input, and 48 V output was built to verify the performance of the proposed converter in boost mode and buck mode, and the feasibility of PI controller combined with feed-forward control strategy. The measured maximum efficiencies with the boost and buck modes were 97.08% and 97.10%, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a new soft switching (SS) multiphase interleaved boost converter (MIBC) consisting of three boost converters (BCs) that operate rapidly and efficiently to charge a lithium-ion battery for photovoltaic (PV) power system applications. This suggested converter can operate both active power switches at zero current switching (ZCS), and when switched off, it works at zero voltage switching (ZVS), which reduces switching losses and increases switching efficiency (SF). An interleaving structure is employed to decrease the conduction losses and reduce the input current ripple (ICR) and output voltage ripple (OVR) to increase the power rating. The suggested converter regulates the input and output power by modulating the phase shift in the pulse width modulation (PWM) technique using the maximum power point tracking (MPPT) algorithm via two closed feedback loops, one for a slower external loop and the other for a faster PWM control internal loop, similar to current mode control. The suggested converter has high voltage (HV) gain due to the coupled inductors (CIs), which act as a transformer. This magnetic design structure in both the steady-state and transient states also decreases the size and enhances the converter’s performance. Finally, the suggested converter was experimentally verified on a 285W prototype, and the maximum efficiency was found to be 98%, based on modeling and experimental data.

This paper presents an ultra-high voltage gain power converter designed to address the challenges posed by the inherently low output voltage and high output current of fuel cell systems. The proposed converter features a two-stage integrated design, comprising a two-phase interleaved boost converter and a high-gain switched capacitor coupled inductor boost converter. The interleaved design divides the current equally between two phase legs, minimising conduction losses and enhancing efficiency. Additionally, this technique significantly reduces input current ripple, leading to lower fuel cell degradation and improved performance. The switched capacitors and coupled inductor in the high gain boost converter enhance the voltage gain while minimising voltage stress on the active switches and diodes. This approach enables the utilisation of low voltage rated switches and diodes, reducing costs and minimising conduction and switching losses. Additionally, the converter features a common input and output ground to mitigate electromagnetic interference and uses low-side switches to simplify gate circuitry and reduce costs. To validate the proposed design, a 500W prototype is developed and tested in a laboratory environment. The prototype achieves a peak efficiency of 95.52%, a peak-to-peak input current ripple of less than 1.5%, and a voltage gain of 27.8 at a 50% duty cycle.

An interleaved Buck-Boost-Zeta converter with the coupled inductor multiplier cell and zero input current ripple is proposed in this paper, which is suitable for high step-up applications such as the photovoltaic generation system. By integrating the Buck-Boost converter with the Zeta converter and adding the coupling inductor voltage multiplier cell and the auxiliary input inductor, the proposed converter achieves very high voltage gain and very low switch voltage stress. At the same time, very low input current ripple and continuous output current can be achieved, which is friendly to photovoltaic arrays and DC-bus. The leakage inductance energy is absorbed by the passive clamp circuit, the zero-current-switching (ZCS) turn-on of the switch is achieved and the reverse recovery problem of the diode is alleviated. The operation principles and performances of the proposed converter are analyzed in detail. The proposed converter can further improve the voltage gain by adding different voltage multiplier cells and their general structures are given. A prototype with 32V input and 400V output was built to verify the theoretical analysis.

This study comprehensively analyzes the discontinuous conduction mode (DCM) of a two-phase interleaved buck converter (IBC) with an inversely coupled inductor (ICL). With ICL, nine circuit configurations are possible when the IBC operates in the DCM. Depending on the duty ratio and load condition, DCM can also be classified into seven types. Each type of DCM has a corresponding combination of circuit configurations. Consequently, the application of the combinations for distinguishing DCM types is proposed to analyze the DCM operation of two-phase IBCs with ICL. Different DCM types have different DCM characteristics, such as state space averaged models and time interval calculations, which are needed to be analyzed for small-signal modeling. Therefore, the state space averaged models and time intervals equations are derived for each DCM type, and boundary conditions between adjacent DCM types are analyzed. Experimental tests on the hardware prototype of the IBC are conducted to verify the practical effectiveness of the proposed analysis.

Aiming at the application scenario of high voltage transmission rate in distributed power generation systems, this paper proposes a novel high-boost DC-DC converter. The overall design of the converter combines the improved secondary active switching inductor with the coupled inductor. Adoption of staggered conduction, which in turn reduces input current ripple. The voltage gain is further improved by integrating the coupled inductor voltage doubling unit. The passive clamp circuit is used to absorb and utilize the leakage energy of the coupled inductor, which greatly reduces the voltage spike of the switch. In this paper, the working principle and steady-state performance of the converter are analyzed in detail, and the superiority of the proposed converter is proved by the performance comparison between the converters. Finally, a 200W experimental prototype was built for verification, which used common components and measured a maximum efficiency of 92.2%. The experimental results verify the correctness of the theoretical analysis and the feasibility of the proposed converter topology.

This article presents a single-switch high step-up quadratic DC-DC converter for DC microgrid applications. The quadratic boost converter is integrated with switched capacitor cell along with coupled inductor to achieve high gain at reduced duty ratio. The switched-capacitor cell is composed of two diodes and two capacitors. The capacitors charge in parallel and discharge in series to increase the converter’s gain. The coupled inductor turn ratio can be increased to elevate the converter’s gain further. The inductor at the input minimizes the current ripples and makes the input current to be continuous. Moreover, the proposed converter works as a passive clamp circuit to minimize large voltage spikes across the switch (MOSFET) and it has low $R_{ds}$ (on-state) to minimize the conduction losses. As a result, the device’s rating improves, losses decrease, and it becomes less expensive to switching devices of the converter. The energy leakage of the coupled inductor is recycled to the output capacitor, it can reduce the reverse recovery issue in diodes and increases efficiency of converter further. The proposed converter working principle and its analysis are explained with different operating modes. The performance of the converter is validated with laboratory hardware setup with rating of 160W. Here, the input and output voltages are considered at 20V and 400V, respectively. Finally, the superiority of the proposed converter is compared with existing literature in terms of gain, stress across various components, switching performance and efficiency.

Abstract This article proposes an interleaved high step‐up DC–DC converter topology designed for renewable energy applications, featuring an ultra‐high voltage conversion ratio. The converter employs an interleaved structure, resulting in a low peak‐to‐peak ripple in the input source current, which is particularly advantageous for solar PV sources. To enhance the output voltage, the topology utilizes voltage multiplier cells (VMC) and coupled inductor techniques. Two coupled inductors with three windings are integrated into the proposed topology, with the secondary and tertiary windings combined with VMC. This combination effectively reduces the maximum voltage stress across power switches, enabling the use of low‐rated and cost‐effective power switches for implementation. The article offers comprehensive operation modes and steady‐state analyses to demonstrate the converter's performance. A comparison is made between the suggested structure and other similar converter topologies. To validate the mathematical analysis, a 200‐W prototype is constructed, operating at a frequency of 25 kHz and achieving a voltage conversion range of 20 to 409 V. The experimental results are presented to support the findings.

In this paper, a non-isolated DC–DC converter with three-winding coupled inductors and switched capacitor cells is introduced. More output voltage is acquired without imposing any extreme duty cycle and high turns ratio. With the help of a two-phase interleaved technique, the input current ripple is reduced efficiently. The leakage inductance of coupled inductors causes the reverse recovery problem of circuit diodes to be solved and alleviates them. Leakage energy is also absorbed by switched capacitor cells. One of the advantages of this converter is the reduction of voltage stress of power switches, which leads to a reduction of conduction losses. In this way, low-voltage rated power switches can be used. Creating soft-switching conditions on power switches and high efficiency are also the prominent features of this structure. Laboratory and experimental results were produced and presented by making a prototype of 350 W–18 V/480 V. Their analysis indicates the effective performance of the proposed topology. [ABSTRACT FROM AUTHOR]

This paper proposes an ultrahigh synchronous drive step-up dc-dc converter to improve the low voltage generated by proton exchange membrane fuel cell (PEMFC) with proper duty cycle. Coupled inductor and voltage multiplier technologies are utilized to obtain high voltage gain in the converter. The energy stored in leakage inductor can be recycled by the clamp circuit, reducing the voltage stresses on switches, and improving the efficiency significantly. The operating principles and steady-state analyses in continuous conduction mode are provided in detail. Compared with relevant converters, the proposed converter performs lower voltage stresses on power switches and higher voltage gain. Moreover, to improve the dynamic performance and interference immunity of the proposed converter, the offline fitting strategy using the explicit model predictive control (MPC) laws of neural networks is used. The tracking accuracy of the output voltage is improved, disturbances caused by variable loads are reduced, and superior dynamic response can be achieved. Finally, to verify the feasibility and validate the theoretical analyses, a 200 W laboratory prototype with input voltage 20 V and output voltage 400 V is implemented. The maximum efficiency of the proposed converter is 97.21% and the full load efficiency is 91.67%. • Design an ultrahigh synchronous drive step-up dc-dc converter for PEMFC. • The offline fitting strategy with the explicit model predictive control laws of neural networks is used. • High voltage gain and efficiency are achieved in less components. [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]

Summary: In this study, a novel non‐isolated DC‐DC converter based on magnetic coupling and voltage multiplier technique has been proposed. The output voltage of the suggested converter can be enhanced by selecting the appropriate turn ratio of the coupled inductor. To further improve the voltage gain, a voltage multiplier circuit including the capacitors and diodes has been utilized in this converter. The main features of the proposed converter are a high voltage conversion ratio, high efficiency, and lower peak voltage throughout the semiconductor devices. Besides, there are soft switching conditions throughout the diodes of the presented topology, which leads to reducing the reverse recovery losses of the diodes and subsequently improving the overall efficiency of the system. Also, only one insulated‐gate field‐effect transistor (MOSFET) has been used in the structure of the converter. Thus, the switch with lower on‐state resistance can be selected for the suggested converter that decreases the conduction losses. To prove the performance of the suggested structure, the operational analysis, mathematical descriptions, efficiency analysis, and comparison survey with similar structures in the literature have been described. Finally, a laboratory prototype with 200 W output power with 95.14% load efficiency, 20 V input voltage, and 260 V output voltage at 50 kHz switching frequency has been provided. [ABSTRACT FROM AUTHOR]

Dc microgrids (MG) have drawn more attention due to the demand for renewable energy sources, energy storage devices in distributed generation, and the separation of DC loads requiring more power converters. This system needed protection DC circuit breakers (DCCB) that could quickly isolate the faults in the system. These devices must be as small and light as possible but should only produce low power loss during the ON state. The impedance source DC circuit breaker was introduced as an improved structure (SSCB) which provided automatic turns off without needing external command due to its natural commutation operation principle. In addition, it had many advantages such as faster response, simpler control design, restricted fault current magnitude, which makes the system more fault-resilient, the fault current will not affect the source or the SCR, coordination of cascaded breakers is automatic, and convenience for protection with power converters. This paper presents different impedance source DC circuit breakers such as ZCB, CCB, TCB, and YCB. It will show their benefits and drawbacks, which could be used as a helping guide while choosing which type of impedance source DC circuit breakers is suitable for a specific application. [ABSTRACT FROM AUTHOR]

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This article proposes an interleaved high step‐up DC–DC converter topology designed for renewable energy applications, featuring an ultra‐high voltage conversion ratio. The converter employs an interleaved structure, resulting in a low peak‐to‐peak ripple in the input source current, which is particularly advantageous for solar PV sources. To enhance the output voltage, the topology utilizes voltage multiplier cells (VMC) and coupled inductor techniques. Two coupled inductors with three windings are integrated into the proposed topology, with the secondary and tertiary windings combined with VMC. This combination effectively reduces the maximum voltage stress across power switches, enabling the use of low‐rated and cost‐effective power switches for implementation. The article offers comprehensive operation modes and steady‐state analyses to demonstrate the converter's performance. A comparison is made between the suggested structure and other similar converter topologies. To validate the mathematical analysis, a 200‐W prototype is constructed, operating at a frequency of 25 kHz and achieving a voltage conversion range of 20 to 409 V. The experimental results are presented to support the findings. [ABSTRACT FROM AUTHOR]

A novel high-gain and high-efficiency direct current to direct current (DC-DC) converter is introduced in this paper. The presented converter is suitable for low-voltage renewable energy resources such as photovoltaic (PV) and fuel cell (FC). The existence of series inductance with the input source ensures continuous and low-ramp input current, which is important for extracting maximum power from resources. Using coupled inductor technology and an intermediate capacitor in the suggested converter leads to a high gain voltage. In the presented topology for recovering energy from the leakage inductor, reducing voltage stress on the power switch, and so decreasing overall converter losses, a passive clamp circuit is used. The suitable operation range of duty cycle in the converter, besides the leakage inductor, decreases the problem of reverse recovery in diodes. The low value of the leakage inductor and the low volume and cost of the proposed converter are due to the low turn ratio of the coupled inductor. Details of the operation principles of the proposed converter have been discussed in this paper. The presented simulation and laboratory prototype results verify the theoretical analysis and performance of the suggested topology. [ABSTRACT FROM AUTHOR]

This paper presents a novel single-phase non-isolated bidirectional buck converter topology. The proposed converter uses a basic switching cell structure with a coupled inductor and an interleaving switching scheme. This article addresses a crucial challenge in bidirectional DC-DC conversion by prioritizing reducing output current ripples and minimizing filter inductor size. The employed method includes using MOSFETs with fast recovery diodes to mitigate reverse recovery and body diode losses. Furthermore, the optimization of the switching frequency of the output inductor to be twice the actual switching frequency contributes to reducing the component size of the converter. The coupled inductor also helps to reduce stress on components by distributing currents among its legs. The experimental result demonstrates the proposed converter has a very low ripple current as compared to the conventional converter. The low current ripples and smaller filter inductor size enabled by high-frequency operation have improved the efficiency and size of the converter. A common ground between input and output terminals ensures robust performance without common mode current concerns. Overall, the proposed converter represents a significant improvement in DC-DC converters, promising enhanced efficiency, reliability, and compactness in bidirectional DC-DC conversion systems. In order to verify the performance of the proposed converter, a 460 W buck converter prototype was built and tested.

A decoupled model predictive control (MPC) power balancing strategy for a coupled inductor-based flying capacitor DC–DC converter (FCDC) is a proposed to solve the power imbalance caused by the parameter differences in the coupled inductor. The decoupled mathematical model of coupled inductor FCDC is firstly derived by analyzing the converter operation state under various modes. On this basis, the control relationship between inductor current and flying capacitor (FC) voltage is redefined and an MPC power balance strategy based on the inductor current with single-step optimization is proposed. The proposed MPC strategy not only achieves decoupled power balancing control but also solves multi-objective dynamic optimization control of the inductor current and FC voltage, greatly reducing the computation load. A detailed theoretical analysis of the proposed strategy is presented and the balancing performance is effectively verified through the experiments.