Voltage Gain Analysis Research Articles

Enhancing off-grid wind energy systems with controlled inverter integration for improved power quality

Introduction. Off-grid wind energy systems play a pivotal role in providing clean and sustainable power to remote areas. However, the intermittent nature of wind and the absence of grid connectivity pose significant challenges to maintaining consistent power quality. The wind energy conversion system plays a central role in tapping renewable energy from wind sources. Operational parameters such as rotor and stator currents, output voltages of rectifiers and converters, and grid phase voltage variations are crucial for stable power generation and grid integration. Additionally, optimizing power conversion output through voltage gain analysis in boost converters is essential. Moreover, ensuring electricity quality via total harmonic distortion reduction in inverters is vital for grid compatibility. Goal. Enhancing the power quality of grid-integrated wind energy conversion systems. Methods. The proposed topology is implemented in MATLAB/Simulink with optimized control strategies for enhancing power quality in off-grid wind energy systems. Results. Control strategies with a grid-connected wind energy conversion system yields substantial improvements in power quality. This includes effectively mitigating voltage fluctuations and harmonics, resulting in smoother operation and reduced disturbances on the grid. Practical value. The proposed topology has proven to be extremely useful for off grid-integrated wind system. References 18, table 1, figures 11.

Modeling and simulation analysis of interleaved double dual boost converters in energy storage field

AbstractAlthough interleaved double dual boost converters have been widely studied for energy storage, their detailed feature analysis is rarely discussed. To this end, this paper systematically analyzes features regarding interleaved double dual boost converters to provide the basis of the controller design. First, the topological structure and working principle are introduced, which is an indispensable pretreatment for the steady‐state feature analysis. Second, the voltage gain analysis, and input voltage ripple analysis output voltage ripple analysis, which is an indispensable feature analysis for the following controller design. Furthermore, the relative controller regarding the interleaved double dual boost converter is proposed in this paper. Finally, the simulation and experimental results illustrate the effectiveness of the feature analysis.

New Modular Multilevel DC–DC Converter Derived from Modified Buck–Boost DC–DC Converter

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

Five-Level Step-Up Switched-Capacitor Grid-Connected Inverter

The objective of this paper is to propose a new five-level step-up switched-capacitor grid-connected inverter (FSSGI) The proposed FSSGI, which is composed of a switched-capacitor converter (SCC) and an dc-ac unfolder, is able to operate in standalone and grid-connected mode. Compared with conventional step-up inverter topologies, the advantages of the proposed FSSGI include high conversion efficiency, self-balancing of capacitor, and voltage stress reduction on the switches for low power applications. In addition, the leakage current cause by the high common mode voltage (CMV) can be reduced since the unfolder is only switched at the low frequency. Also, the electrolytic capacitor can be replaced with the long lifetime film capacitor by reducing the required capacitance. The principle of operation, voltage gain analysis, and design methodology are described in this paper. Finally, the computer simulations and hardware experimental results are shown to verify the performance of the proposed FSSGI. A 400-W prototype is built and tested, and the peak and rated power conversion efficiency are 97.89% and 97.45%, respectively.

A novel high‐efficient step‐up converter with continuous input current, common ground, and minimum stress on semiconductors

AbstractThis study proposes a comprehensive analysis of a novel non‐isolated step‐up converter with continuous input current and common ground. The proposed topology provides high voltage gain besides insignificant voltage and current stress across switches and diodes. Consequently, using switches and diodes with low current and voltage withstanding is achievable, leading to high converter efficiency and cost reduction. The voltage and current stress besides steady‐state and efficiency analysis are surveyed. Moreover, the converter's non‐ideal voltage gain analysis employing different components is discussed and compared with recently suggested converters. Additionally, the component losses, efficiency, normalized voltage, and current stresses of the studied converters are collected in tables to simplify the comparison between different topologies. Finally, a 100 W prototype converter is implemented to confirm theoretical performance, and the results are investigated in detail.

Inductorless Bidirectional Switched-Capacitor Power Electronics Transformer

The objective of this article is to propose a new inductorless bidirectional switched-capacitor power electronics transformer (IBSCX) for low-power commercial and residential applications. The proposed IBSCX is composed of multiple switched-capacitor converters (SCCs) and two bidirectional unfolders. Compared with the traditional solution which is the use of a low-frequency transformer, the advantages of the proposed IBSCX include control circuit simplicity, high conversion efficiency, and volume and weight reduction for low-power applications. The principle of operation, voltage gain analysis, and design methodology are described in this article. Also, with the interleaved operation between SCCs, the output current ripple can be reduced. Finally, the computer simulations and hardware experimental results are shown to verify the performance of the proposed IBSCX. A prototype IBSCX is built and tested, and the peak and rated power conversion efficiency are 98.26% and 97.95%, respectively.

Self-sustaining Hybrid Renewable Energy DC Micro Grid System with Ideal Energy Superintendence for AC Load Operation

The paper presents a proposed design of SEPIC with high voltage gain for sustainable energy applications. The suggested circuit is structured by combining the standard SEPIC with a magnifying module. Hence the converter profits from various assets that the specific converter has, like uninterrupted input current. Also, high voltage gain and input current continuity makes the proposed converter applicable for sustainable energy sources. The altered SEPIC converter (MSC) gives higher voltage gain compared to standard SEPIC and recently addressed converters with single-controlled switch. The analysis of voltage gain in continuous current mode (CCM) and discontinuous current mode (DCM) is carried out by considering the non-idealities of semiconductor devices and passive components. The preference of semiconductor devices depending on voltage- current rating is put forward along with the designing of reactive components. The numerical simulation and experimental work is done and the results demonstrate viability of the MSC concept and theoretical analysis.

Multi-Mode Control of a Bidirectional Converter for Battery Energy Storage System

In this paper, a bidirectional converter with multi-mode control strategies is proposed for a battery energy storage system (BESS). This proposed converter, which is composed of a half-bridge-type dual-active-bridge (HBDAB) converter and an H-bridge inverter, is able to operate the BESS with different power conditions and achieve the DC–AC function for lower input DC voltage applications. For the HBDAB converter, the variable-frequency control (VFC) and phase-shift control (PSC) are both adopted to achieve zero-voltage switching over a wider power range and the battery module balance control capability for BESS, respectively. In addition, the interleaved configuration is used to reduce the current ripple and increase the overall current rating. For the H-bridge inverter, the unipolar control mode (UCM) and totem-pole control mode (TPCM) are adopted to manage the real and reactive current control under different AC grid conditions. The UCM offers a reduction in current ripple for real and reactive power control. The TPCM is able to eliminate switching losses and achieve higher conversion efficiency for pure real power control. Considering applications for battery energy storage systems, the principle of operation and voltage gain analysis are described. Finally, computer simulations and hardware experimental results from a prototype system are presented to verify the performance of the proposed converter with the different control strategies.

A hybrid switched inductor with flexible high voltage gain boost converter for DC micro‐grid application

A hybrid switched inductor with flexible high voltage gain boost converter for 400 V DC microgrid application is presented in the paper. The three operating modes of the converter are controlled using three switches by two-duty ratios. The proposed converter provides flexibility in the selection of the duty cycle to achieve desired output voltage. Moreover, with two duty ratio, high gain with a wide duty range is accomplished in the proposed converter while an individual switch does not need to operate at a very large duty ratio. The power circuit analysis, operating principles, steady-state voltage gain analysis during continuous conduction mode (CCM) and discontinuous continuous mode (DCM), boundary condition, efficiency analysis, comparison, and circuit parameter design of the proposed are presented. A closed-loop controller design and small-signal modeling are discussed. The dynamic behavior of the proposed converter is validated with a change in duty ratio, input voltage, and load power. A laboratory prototype converter is designed and developed to verify the model, and feasibility of different operation modes. The prototype is tested for a power range of 100 W–500 W for different duty cycles.

An extended voltage gain buck-boost converter for maximum photovoltaic power extraction

ABSTRACT DC-DC converters are widely used in solar power systems to extract maximum power from solar photovoltaic (SPV) sources by matching the reflected load resistance to the internal resistance of the SPV source. This paper proposes a non-isolated buck-boost converter with extended range of voltage gain operating within practical limits of duty ratio. The gain of the proposed converter has been enhanced by lifting the voltage level of a classical buck-boost converter through a simple auxiliary network, comprising a semiconductor switch, an inductor and a capacitor. In the present work, the proposed converter has been used to extract maximum power from the SPV source with wide range of load resistance and under wide variation in solar irradiance and ambient temperature. Steady-state analysis of voltage gain, boundary condition analysis and design guidelines of the proposed converter have been presented in this paper. Finally, the theoretical analysis has been validated by experimentally verifying the performance of the proposed converter with a laboratory scale hardware prototype, tested with DSPIC33FJ32MC204 microcontroller for maximum power point tracking (MPPT) of SPV source. Real-time performance of the proposed converter has been found to match the predicted behaviour of the SPV system.

High step‐up single switch quadratic modified SEPIC converter for DC microgrid applications

A new non-isolated high-voltage gain single switch quadratic modified single-ended primary-inductor capacitor (SEPIC) DC-DC converter is proposed in this study. The proposed converter consists of a modified SEPIC converter along with a boosting module to obtain a high-voltage gain at a low-duty ratio. It has all advantages of the SEPIC converter such as continuous input current, which makes it applicable for renewable energy sources such as photovoltaic systems. The proposed converter is able to attain a higher voltage gain in comparison with similar previous transformer-less DC-DC converters. Also, unlike high-voltage transformer-based DC-DC converters, it does not suffer from leakage inductances. Also, the proposed converter presents low-voltage stress across the switch and output diode. The proposed converter is controlled through a single switch and there is no limitation for a range of duty ratios. The voltage gain analysis of the proposed converter is done in continuous conduction mode and discontinuous conduction mode, also comparative analysis is done with the existing topologies with similar features. The proposed converter is designed for 400 V DC microgrid applications. The theoretical analysis of the proposed converter is verified by the experimental investigation in the laboratory.

High Gain Switched-Inductor-Double-Leg Converter With Wide Duty Range for DC Microgrid

In a dc microgrid, efficient high gain converters are needed to raise the voltage level of low voltage power sources such as photovoltaic, fuel cells, etc. In this article, a high-gain switched-inductor-double-leg converter for dc microgrid is proposed. The proposed converter is capable of providing higher gain devoid of using any transformer, coupled inductor, and multiple voltage lifting techniques, e.g., triple lift, quadruple lift, super lift, etc. The operating modes of the converter are controlled using three switches in double duty mode. Compared to single duty converter, the double duty converter provides a flexibility in selection of duty cycle for switch to achieve desired output voltage and controlling inductor current ripple magnitude by selecting appropriate duty cycles. Moreover, two duty cycles make the converter capable of achieving high gain with wide duty range and an individual switch does not need to operate at very large duty cycle to achieve high voltage gain. The topological description, operating principles, steady-state voltage gain analysis during continuous conduction mode and discontinuous continuous mode, boundary condition, and voltage and current analysis, efficiency analysis, comparison and design of the proposed are presented. The proposed converter is tested in laboratory to validate its feasibility and performance.

Hold-Up Time Extension Method for LLC Resonant Converter by Detecting Operation Region

An LLC resonant converter is widely used due to the low-voltage stress and zero-voltage-switching (ZVS) capability. The LLC resonant converter should operate in the inductive region due to the ZVS operation. For the stable ZVS operation, a sufficient margin of the maximum operation gain should be guaranteed because the theoretical peak voltage gain analysis is not well-matched with the experimental peak gain. Therefore, it is hard to use the peak gain of the LLC resonant converter. As a result, to satisfy enough hold-up time, there are many side-effects such as a large link capacitor and an unoptimized design for high efficiency. This letter proposes a new hold-up time extension method for the LLC resonant converter, which can use the peak gain without margin by detecting the accurate peak gain point. By using the proposed method, the hold-up time can be extended, and the link capacitor can be reduced for high power density. The feasibility of the proposed structure is confirmed with a 500 W prototype.

ZVS Auxiliary Circuit for a 10 kW Unregulated LLC Full-Bridge Operating at Resonant Frequency for Aircraft Application

In modern aircraft designs, following the More Electrical Aircraft (MEA) philosophy, there is a growing need for new high-power converters. In this context, innovative solutions to provide high efficiency and power density are required. This paper proposes an unregulated LLC full-bridge operating at resonant frequency to obtain a constant gain at all loads. The first harmonic approximation (FHA) model is not accurate enough to estimate the voltage gain in converters with high parasitic resistance. A modified FHA model is proposed for voltage gain analysis, and time-based models are used to calculate the instantaneous current required for the ZVS transition analysis. A method using charge instead of current is proposed and used for this ZVS analysis. Using this method, an auxiliary circuit is proposed to achieve complete ZVS within the whole load range, avoiding a gapped transformer design and increasing the efficiency and power density. A 28 Vdc output voltage prototype, with 10 kW peak output power, has been developed to validate the theoretical analysis and the proposed auxiliary circuit. The maximum efficiency (96.3%) is achieved at the nominal power of 5 kW.

A New Structure of High Voltage Gain SEPIC Converter for Renewable Energy Applications

The paper proposes a new structure of SEPIC with high voltage gain for renewable energy applications. The proposed circuit is designed by amalgamating the conventional SEPIC with a boosting module. Therefore, the converter benefits from various advantages that the SEPIC converter has, such as continuous input current. Also, high voltage gain and input current continuity make the presented converter suitable for renewable energy sources. The modified SEPIC converter (MSC) provides higher voltage gain compared to the conventional SEPIC and recently addressed converters with a single-controlled switch. The analysis of voltage gain in continuous current mode (CCM) and discontinuous current mode (DCM) is analyzed by considering the non-idealities of the semiconductor devices and passive components. The selection of the semiconductor devices depending on the voltage-current rating is presented along with the designing of reactive components. The numerical simulation and experimental work are carried out, and the obtained results prove the feasibility of the MSC concept and the theoretical analysis.

High Gain Transformer-Less Double-Duty-Triple-Mode DC/DC Converter for DC Microgrid

High-gain DC/DC converters with high efficiency are needed in dc microgrid owed to the low voltage of power sources, e.g., photovoltaic-cell and fuel-cell. This paper proposed a new high-gain double-duty-triple-mode (DDTM) converter for dc-microgrid applications. The proposed DDTM converter operates in three modes to achieve higher voltage gain without utilizing transformer, coupled inductor, voltage multiplier, and multiple voltage lifting techniques, e.g., triple, quadruple voltage lift. The modes of operation of the converter are controlled through three switches with two distinct duty ratios (double duty) to achieve wide range duty ratio. The operating principle, voltage gain analysis, and efficiency analysis of the proposed converter are discussed in detail and to show its benefits comparison is provided with the existing high-gain converters. The boundary operating condition for continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is presented. The prototype of the proposed converters with 500-W power is implemented in the laboratory and experimentally investigated, which validate the performance and feasibility of the proposed converter. Due to double duty control, the proposed converter can be controlled in different ways and the thorough discussion on controlling of the converter is provided as a future scope.

Modeling, Analysis, and Parameters Design of LC-Filter-Integrated Quasi-Z -Source Indirect Matrix Converter

Through coupling the impedance network between the grid and the conventional indirect matrix converter (IMC), the LC -filter-integrated quasi-Z-source (qZS) IMC overcomes the 0.866 voltage gain limitation of the conventional IMC and also avoids the input filter that is required to mitigate current harmonics of the conventional qZS matrix converters. This paper further investigates the voltage boosting and LC filtering function of the LC -filter-integrated qZS IMC. The voltage gain, the filtering function, and qZS network parameters design are presented using a small-signal model and circuit analysis. Simulation and experimental results validate the built model, the voltage gain analysis, and the parameters design of this type of qZS IMC. The input current of the LC -filter-integrated qZS network is compared to the conventional Z-source and qZS IMCs to investigate the integrated LC filtering capability. The experimental results verify that the LC -filter-integrated qZS network provides the necessary filtering function. Thus, the traditional input filter can be eliminated, which reduces the cost, power loss, volume, and weight for the overall system, when compared with the other conventional topologies that require the input filter, even those with impedance-source networks.

Voltage gain analysis of the interleaved boost with voltage multiplier converter used as electronic interface for fuel cells systems

The connection of low power renewable energy sources, such as fuel cells, to the distribution generation system requires power electronics structures with high voltage gain, high capability to power processing and consequently, high levels of current flowing through the dc/dc converter. In this context, this study analyses how the parasitic resistances of the passive components and the load power demand affect the dc/dc converter voltage gain. Taking into account the mathematical model, the boundaries of operation of the Interleaved Boost with Voltage Multiplier converter is determined through a set of equations and by means of a graphical analysis. The theoretical analysis, simulations and experimental results are used to validate the proposed approach presented in this study.

Analysis and Design of a PFC AC-DC Converter with Electrical Isolation

This study presents a single-phase power factor correction AC–DC converter that operates in discontinuous conduction mode. This converter uses the pulse-width modulation technique to achieve almost unity power factor and low total harmonic distortion of input current for universal input voltage (90 Vrms to 264 Vrms) applications. The converter has a simple structure and electrical isolation. The magnetizing-inductor energy of the transformer can be recycled to the output without an additional third winding. The steady-state analysis of voltage gain and boundary operating conditions are discussed in detail. Finally, experimental results are shown to verify the performance of the proposed converter.

Novel High Step-Up DC–DC Converter With Coupled-Inductor and Switched-Capacitor Techniques for a Sustainable Energy System

In this paper, a novel high step-up dc–dc converter is proposed for a sustainable energy system. The proposed converter uses coupled-inductor and switched-capacitor techniques. The capacitors are charged in parallel and discharged in series by the coupled inductor to achieve high step-up voltage gain with an appropriate duty ratio. Besides, the voltage stress on the main switch is reduced with a passive clamp circuit; low on-state resistance R <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$_{\bf {ds(on)}}$</tex></formula> of the main switch can be adopted to reduce the conduction loss. In addition, the reverse-recovery problem of the diode is alleviated by a coupled inductor. Thus, the efficiency can be further improved. The operating principle and steady-state analyses of voltage gain are discussed in detail. Finally, a prototype circuit with 24-V input voltage, 400-V output voltage, and 200-W output power is implemented in the laboratory to verify the performance of the proposed converter.