Non-isolated High Step-up DC-DC Converter Research Articles

Non-isolated high step-up DC-DC converters based on geometric structure model

Non-isolated high step-up DC-DC converters based on geometric structure model

Nonisolated High Step-Up DC–DC Converters: Comparative Review and Metrics Applicability

Due to the extensive role of non-isolated high step-up DC-DC converters (NHSDC)s in industrial applications and academic research, many of these pulse width modulation converters have been presented in recent years. For each of these NHSDCs, some claims are introduced to verify its capabilities and features, which has been investigated in some review papers with different frameworks. Dissimilar to previous review papers, which have focused on the classification and derivation of voltage boosting techniques, this paper aims to evaluate the converters from various topological and operational points of view, and determine the superiority of each technique and converter according to applications. Some of these metrics are voltage gain, stresses, ripple, cost, power density, weight, size, control complexity and components count which lead to a comprehensive comparative study. Then, as the main purpose of this paper, effectiveness of these metrics is assessed to show how well they can lead us to the fair comparison results. Moreover, some new figures of merit are proposed in this paper to provide a helpful guideline in power electronic converters comparison studies. Finally, the feasibility discussion of single- and multi-objective figures of merit is followed by general practical conclusion and outlook about the NHSDC structures.

Analysis and Design of Switched LC Converter With Reduced Voltage Stress for Photovoltaic Applications

High step-up voltage conversion is required in renewable energy systems. This paper presents a non-isolated high step-up DC-DC converter based on active switched-inductors (ASL) with switched capacitor cells (SCC). The unique selling proposition of the proposed converter is division of input current which reduces the inductor size. In the proposed topology, the capacitor and diode are arranged in such a way that they interconnect the input to the load side for obtaining high step-up ratio. The main advantages of the converter are high step-up ratio at a low duty cycle with low switch stress and low component count. Operating principles, design equations, and device stress are included in this paper. Moreover, small-signal analysis and its bode plots are presented here. In addition, the loss distribution is critically investigated. Finally, to verify the theoretical study, a laboratory prototype is built and tested at different operating points in continuous conduction mode (CCM).

Design and analysis of a high-gain dual-input single-output DC-DC converter for hybrid energy systems applications

<span lang="EN-US">The high gain converters are one among the proven topologies that are found attractive for industrial and commercial applications. They deal with high power ratings like automobile headlamps, energy backup systems, and fuel cell electric vehicles (FCEV). In literature, most of the topologies were used a single duty ratio. This may not be reliable for high-duty cycle operation because to improve the voltage gain, the components will be increases. This paper proposes the time-sharing concept based on the non-isolated high step-up dc-dc converter. With the parallel-charged and series-discharged inductors, the proposed converter can produce high output voltage gains. The effectiveness of the proposed circuit configuration is verified in MATLAB/Simulink and the results are corroborated by theoretical analysis.</span>

A Novel Three-Winding Coupled Inductor-Based High Step-Up DC-DC Converter for Renewable Energy Application

This paper presents a novel nonisolated high step-up dc-dc converter for renewable energy generation system. The converter combines a three-winding coupled inductor, voltage multiplier cells, and two power switches with simultaneous operation. Compared with existing high step-up converters, the proposed converter can achieve high voltage gain under a low number of turns ratio while avoiding a large duty cycle. Moreover, the passive clamp circuit recycles leakage inductor energy and reduces the voltage spike of switches. Continuity of input current and existence of a common ground between the input energy source and load make the converter suitable for renewable energy applications. Also, the proposed converter shares high voltage gain with low voltage stress on semiconductors (switches/diodes), improved compactness and high efficiency. The operating principles and steady-state analysis of the proposed converter are illustrated. Then the theoretical efficiency analysis, and performance comparison with other converters are discussed. Finally, a 200 W prototype with 380 V output voltage is established based on the design guidelines, and experimental results verify the accuracy of the theoretical analysis.

A Nonisolated Single-Switch Coupled Inductor-Based DC-DC Converter with High Voltage Gain for Renewable Power Generation Systems

This article proposed a new structure of nonisolated high step-up DC-DC converter based on a three-winding coupled inductor and voltage multiplier cells (VMCs) for renewable energy systems applications such as PV power generation. Continuous input current with low ripple, common ground between output and input ports, low voltage stress across semiconductors, low number of components, high voltage gain, and high efficiency are the main advantages of the proposed converter. In order to further increase the output voltage, the windings of the coupled inductor are combined with VMC. The combination of coupled inductor and VMC technique leads to a high voltage gain with low duty cycle, and therefore the conduction loss of power switch is reduced. Additionally, the diodes’ reverse recovery currents are reduced which improve the presented topology’s efficiency. On the other hand, the used VMCs clamp the voltage, and the peak voltages across power switch are decreased. The operational modes, steady-state, and efficiency analysis are discussed. Also, to demonstrate the performance of the recommended converter, an experimental prototype with 580 W output power and 400 V output voltage with the switching frequency of 25 kHz is built and the experimental results are presented. Also, another 1 kW, 400 V with the switching frequency of 50 kHz has been implemented and tested.

A Review of Non-isolated High Step-up DC-DC Converter Structures and Simulation Analysis of a High Gain Quadratic Converter

A Review of Non-isolated High Step-up DC-DC Converter Structures and Simulation Analysis of a High Gain Quadratic Converter

A high step-up non-isolated DC-DC converter with active switched-inductor and switched-capacitor networks

ABSTRACT This article proposes an enhanced non-isolated high-gain DC-DC converter for interfacing renewable energy sources (RESs). This converter utilizes active switched-inductor (ASL) and switched-capacitor (SC) networks in which the ASL network increases the voltage gain. Furthermore, using the SC network as a multiplier cell helps to reach a high voltage conversion ratio with a proper duty cycle. The main advantages of the proposed converter are the high voltage gain, continuous input current, and low voltage stress on the semiconductor switch and the passive component. Since the voltage stress of the semiconductor element is low, a low ON-state resistance switch is used, which leads to reduced conduction losses. Comprehensive analysis of the steady-state operation in continuous conduction mode (CCM), inductor and capacitor design, and a comparison considering other similar topologies are presented in this article. Also, the parasitic elements are assumed to calculate the DC-Voltage gain and the efficiency of the converter. Finally, simulation results are presented in the PSIM environment to validate the feasibility of the proposed converter.

A Non-Isolated High Step-Up DC-DC Converter Using Voltage Lift Technique: Analysis, Design, and Implementation

This paper presents a new structure for non-isolated and non-inverting DC-DC converters with high voltage gain harnessing the fundamentals of the voltage lift technique. The proposed topology is a suitable structure for low voltage applications. The operation principles, the steady-state relations, and different switching strategies to further improve the voltage gain performance of the proposed converter are described. A hybrid utilization of complementary switching approach and simultaneous switching of two switches is proposed to achieve the highest voltage gain in different duty cycles. Furthermore, a theoretical analysis of power losses is provided. The suggested DC-DC converter architecture features high voltage gain, high efficiency, and low stress on semiconductor devices. In order to demonstrate these advantages, the structure is compared with some recently-presented high step-up converters in terms of efficiency, voltage gain, and voltage stress. Moreover, A 200W laboratory prototype is developed with experiments carried out to validate the given theories and feasibility of the proposed converter topology.

Design of New High Step-Up DC-DC Converter Topology for Solar PV Applications

A new topology for high step-up nonisolated DC-DC converter for solar PV applications is presented in this paper. The proposed high-voltage gain converter topology has many advantages like low-voltage stress on the switches, high gain with low duty ratio, and a continuous input current. The analytical waveforms of the proposed converter are presented in continuous and discontinuous modes of operation. Voltage stress analysis is conducted. The voltage gain and efficiency of the converter in presence of parasitic elements are also derived. Performance comparison of the proposed high-gain converter topology with the recently reported high-gain converter topologies is presented. Validation of theoretical analysis is done through the test results obtained from the simulation of the proposed converter. For the maximum duty ratio of 80%, the output voltage of 670 V is observed, and the voltage gain obtained is 14. Comparison of theoretical and simulation results is presented which validates the performance of the proposed converter.

Closed-Loop Control of a New High Step-Up Multi-Input Multi-Output DC-DC Converter

Abstract: A new multi-input multi-output dc-dc converter with high step-up capability for wide power ranges is proposed in this paper. The converter's number of inputs and outputs is arbitrary and independent of each other. The proposed topology combines the benefits of DC-DC boost and switched-capacitor converters. The number of input, output, and voltage multiplier stages is arbitrary and depends on the design conditions. First, the various operating modes of the proposed converter are discussed. The closed-loop control system also must be designed using state space representation and small-signal modelling. Finally, the operation of the proposed converter is derived from the simulation results. Keywords: High power converter, Low voltage stress, Multi-Input Multi-Output (MIMO) converter, Non-isolated high step-up dc-dc converter, closed loop control.

A novel high step-up non-isolated DC-DC converter using VL technique for perovskite PV cells

PurposeAt first, the organic/inorganic and hybrid PV materials by their electrical model are described. Then the proposed converter topology, circuit analysis and various operating modes of converter according to on/off timing of switches are investigated. The current and voltage in the converter components are illustrated and the voltage gain and switching stress of proposed converter are presented. Finally, to show the effectiveness of the proposed converter, the power loss analysis is provided and the simulation is done in PSIM software. In the last section, the advantages of the proposed topology of higher efficiency by lower number of components in compare with other conventional topologies are presented.Design/methodology/approachIn this paper, an improved topology of DC-DC converter based on VL technique is proposed for Perovskite Solar cells (PeSCs). The PeSCs attracted a lot of interest due to their potential in combining the advantages of both organic and inorganic components. The proposed converter by using fewer components and higher output voltage generation in compare with conventional ones could be a good candidate for PeSCs due to lower efficiency of this cells. The performance of converter is expressed in continuous conduction mode (CCM) and discontinuous conduction mode (DCM), and the boundary conditions for the proposed converter is presented.FindingsBy using VL technique, this converter is used to boost the lower output voltage levels of PeSCs for grid connection. The PV cell output voltage is increased from 24.5 V to 106 V by proposed converter topology. The step-by-step voltage increasing by charging and discharging of inductor and capacitor is used for boosting the input voltage. By comparing other converters, there is no design complexity in the proposed converter structure, and the power loss is much reduced which increases the converter efficiency. On the other hand, due to using lower number of elements of energy storage elements such as inductors and capacitors, the converter cost is also diminished. Therefore, the design topology simplicity which result simple control algorithm and lower number of components which diminish the system cost by appropriate voltage boosting capability are the main advantages of this proposed topology for new PeSCs which don’t have enough efficiency in compare with old Si PV cells.Originality/valueIn this paper, by using the lower number of components a new structure of DC-DC converter based on the VL technique is proposed. The advantages of this converter such as the simplicity, easier control and high voltage gain by lower power loss, could make this converter a good candidate for new PeSCs where the system whole efficiency will be a critical point to have the unique properties of this new materials in lower loss.

A ZVT Auxiliary Circuit for High Step-Up Multi-Input Converters with Diode-Capacitor Multiplier

In this paper, a Zero-Voltage Transition (ZVT) non-isolated high step-up multi-input DC-DC converters is proposed which employs an auxiliary cell and diode-capacitor multiplier. The auxiliary cell has only one switch and is suitable for high step converters with diode-capacitor multiplier. In the proposed converter, all semiconductor devices operate under fully soft switching condition. The main switches turn on and turn off under Zero Voltage Switching (ZVS) condition whereas the auxiliary switch turns on under Zero Current Switching (ZCS) condition and turns off under zero Voltage and Zero Current Switching (ZVZCS) condition. Also, ZCS condition at turn-off is provided for all diodes to eliminate reverse recovery issue. The structure of the proposed converter includes two boost cells, one diode-capacitor multiplier cell, and one ZVT auxiliary circuit. Soft switching conditions for all main switches are provided by only one auxiliary circuit. The proposed converter has high step-up conversion gain without any coupled inductor. Soft switching conditions, continuous current of input sources, high efficiency, expansion capability of input sources, returning the energy of the auxiliary circuit to the diode-capacitor multiplier and low-voltage stress on switches are the main advantages of the proposed converter. The steady-state analysis of the converter and operation modes are discussed. A 160-W prototype of the proposed converter is designed and implemented. Experimental results confirm that the theoretical and the efficiency of the proposed converter reaches 96.4% at the nominal load.

Non-Isolated Coupled Inductor Based DC-DC Converter with High Voltage Conversion Ratio Recommended for Renewable Applications

In this work, a high step-up non-isolated DC-DC converter with a coupled inductor is introduced for renewable applications. The output voltage rate of the proposed structure is efficiently excesses by choosing an appropriate turn’s ratio of the coupled inductor. The voltage lift elements are utilized to further increase the voltage gain and also leads to a decrease in the voltage spike through the switch. The produced leakage inductance energy of the coupled inductor can be retrieved which leads to a decrease in the power losses of the suggested converter. Moreover, conduction losses are decreased by utilizing only a single switch with lower ON-state resistance R DS-ON. In order to indicate the proficiency of the recommended structure, technical analysis and the comparison survey with other studies are carried out in the literature. Finally, a laboratory scheme at a 200 V/200 W with 24 V input voltage and 95.8% efficiency is prepared to prove the effectiveness of the suggested converter.

A High Step-Up Interleaved DC-DC Converter With Voltage Multiplier and Coupled Inductors for Renewable Energy Systems

This paper proposes a new interleaved non-isolated high step-up dc-dc converter for interfacing renewable energy applications. The proposed converter achieves a very high step-up voltage gain by using two coupled inductors and a voltage multiplier cell. This topology utilizes the interleaved boost converter in the input side, and the input current is shared with low ripple. Moreover, a voltage multiplier cell with the secondary windings of the coupled inductors is employed in the output side to achieve the interleaved energy storage. The voltage stress on the semiconductor switches and the passive components is significantly reduced and lower than the output voltage. The aforementioned converter can be operated without an extreme duty cycle or a high turns ratio. The reverse recovery problem of the diodes is mitigated, and the leakage energy is recycled. Furthermore, by implementing low-voltage-rated MOSFETs with a small ON-resistance, the conduction losses can be reduced, and the efficiency can be improved. The topology is fed by a single input voltage, and the mathematical expression is methodically explored. The operation principle of the proposed converter and the comparison between the proposed converter with other topologies are discussed. The design, parameters selection, and experimental results are thoroughly introduced. A 32 to 800 V-dc is verified and simulated by using PLECS. Consequently, a 400 W hardware prototype is verified to validate the theory and the design.

High step‐up DC–DC converter with coupled inductor suitable for renewable applications

In this study, a new non-isolated high step-up DC-DC converter is presented with high-voltage gain which is suitable for renewable applications. The proposed converter uses coupled inductor and voltage multiplier cell (diode capacitor) for increasing the voltage level. The voltage gain of the proposed converter can be increased by selecting the appropriate turns ratio of coupled inductor. Voltage multiplier cell consists of two diodes and two capacitors which are used to obtain high-voltage gain. The diode-capacitor cell is used as a clamp circuit, which leads to reducing the voltage stress across the semiconductors. The proposed converter has a single power switch which causes the control of the proposed converter is simple. Also, the power switch is used with lower ON-state resistant ( R DS-ON ). The zero-current switching of the diode is obtained in OFF state. Therefore, the conduction losses are decreased with lower normalised voltage stress across semiconductors. To prove the performance of the proposed converter, theoretical analysis and comparison with other converters are provided. To confirm the benefits of the proposed converter, a laboratory prototype with 20 V input voltage, 200 V output voltage and about 200 W power level at operating 25 kHz is built and tested.

Soft-switched non-isolated high step-up multi-port DC-DC converter for hybrid energy system with minimum number of switches

This paper proposes a non-isolated high step-up multi-input DC-DC converter for utilizing in hybrid applications. This converter provides the interfaces between input power sources, energy storage devices and load. The resonant auxiliary circuit used in the proposed converter provides soft switching condition for the main switches as well as charging the storage device which has caused considerable improvement in the converter efficiency. This converter uses only three switches to control the power absorbed from a unidirectional input, the power absorbed or stored in the bidirectional port and also the power transmitted to load while provides soft switching condition of all semiconductor devices. Thus, the number of switches applied is same as conventional hard switched converters for this purpose. This converter shares only one inductor between all inputs, so the volume is reduced. Various converter operating modes are discussed and design considerations are presented. Finally, to validate the theoretical analysis, a prototype of the proposed converter is implemented for a 400 V output voltage at 200 W.

High step‐up DC–DC converter using one switch and lower losses for photovoltaic applications

In this study, a new non-isolated high step-up dc-dc converter using one switch and low-voltage stress on semiconductors is presented for photovoltaic applications. The proposed converter consists of one switch in the input side ( S ), voltage multiplier units (D-C-L), one diode in the output side ( D o ) and one capacitor ( C o ). To achieve high-voltage gain and power level, the proposed converter can be extended to n stages of voltage multiplier units. Hence, the output voltage level will be reasonably increased and the nominal value of power devices will be decreased. Therefore, the voltage stress across the power switch is decreasing for different duty cycles at high power levels. As a result, the efficiency of the proposed converter can be increased by using one switch with lower resistance r DS(on) . To verify the carried mathematical analysis of the proposed converter and circuit implementation are validated through both the simulation and experimental results that accordance each other well. The experimental results of two prototypes (with n = 2, 3) in about 290 W operating at 33 kHz are provided.

Hybrid modular converter for DC microgrids

A novel non-isolated high step-up high-power DC-DC converter based on coupled inductor (CI) and voltage multiplier cell (VMC) for renewable energy DC microgrids is presented in this study. A hybrid combination of three-phase interleaved boost converter with three CIs is chosen to reduce the current ripple at the input and meet the high-power requirement. Three VMCs connected at the secondary side of the CIs serve as gain extension cells. The voltage stress experienced by the switches is only a fraction of the output voltage as the gain extension is mainly achieved at the secondary side of CIs. Practical results obtained from the proposed converter which operated from a 60 V input and provided an output voltage of 1.1 kV while delivering 3 kW of output power prove the correctness of the design details and validate the proposed concept.

A modified high step-up non-isolated DC-DC converter for PV application

A non-isolated high voltage gain DC-DC converter has been presented in this paper. The boost, SEPIC and modified SEPIC converters were analyzed and their performance was compared with the proposed converter. The proposed converter has been designed for the input voltage of 15 V and an output voltage of 150 V with 100 W output power. The efficiency of the converter obtained was 92.5%, which is higher than that of the other converter models which were analyzed. Also, the proposed converter utilizes reduced input current and shows low switching voltage stress. The time response analysis conveys that the proposed converter settles to the steady state voltage and current faster than the other compared converters.