DC Converter Research Articles

Comparative analysis and control design of two non-isolated DC–DC converters with high reduction ratio

Comparative analysis and control design of two non-isolated DC–DC converters with high reduction ratio

Synthesis and Classification of Boost/Buck Structures for Getting Transformerless Hybrid Bidirectional DC–DC Converters

Synthesis and Classification of Boost/Buck Structures for Getting Transformerless Hybrid Bidirectional DC–DC Converters

A Single-Inductor Multiple-Output DC–DC Converter With Fixed-Frequency Victim-Last Charge Control for Reduced Cross Regulation

A Single-Inductor Multiple-Output DC–DC Converter With Fixed-Frequency Victim-Last Charge Control for Reduced Cross Regulation

Single-Stage Isolated AC–DC Converter Based on LCL Resonant DAB Converters With Single-Loop Control

Single-Stage Isolated AC–DC Converter Based on <i>LCL</i> Resonant DAB Converters With Single-Loop Control

Noise Tolerance Strategy Based on Virtual Capacitor for DC–DC Converters With Continuous Control Set Model Predictive Control

Noise Tolerance Strategy Based on Virtual Capacitor for DC–DC Converters With Continuous Control Set Model Predictive Control

A 100-MHz High-Efficiency Cross-Coupled Stacked Rectifier in Isolated DC–DC Converter

A 100-MHz High-Efficiency Cross-Coupled Stacked Rectifier in Isolated DC–DC Converter

A High-Efficient Single-Switch, Soft-Switching High Step-Up DC–DC Converter With a Simple Structure and Continuous Input Current for Renewable Energy Integration

A High-Efficient Single-Switch, Soft-Switching High Step-Up DC–DC Converter With a Simple Structure and Continuous Input Current for Renewable Energy Integration

Capacitive Coupled Step-Down DC–DC Converter With Touch Current Limitation

Capacitive Coupled Step-Down DC–DC Converter With Touch Current Limitation

Steady‐State and Transient Analysis of LLC and iLLC Resonant DC–DC Converters with Wide Voltage Operations Using GaN Technology for Light‐Duty xEV Charging Systems

Steady‐State and Transient Analysis of LLC and iLLC Resonant DC–DC Converters with Wide Voltage Operations Using GaN Technology for Light‐Duty xEV Charging Systems

Coordinated Control of Constant Output Voltage and Maximum Efficiency in Wireless Power Transfer Systems

This article presents a coordinated control method used for wireless power transfer (WPT) systems. This method can improve WPT system transmission efficiency while maintaining the constant output voltage. First, the topology of the DC–DC converter is selected and the equivalent circuit model of the WPT system is established. Then, the WPT system characteristics are discussed and the mutual inductance estimation process is presented. Furthermore, the coordinated control method is proposed, where the constant voltage output is achieved by connecting the Buck–Boost converter after the diode rectifier. Meanwhile, the optimal phase shift angle is calculated and sent to the controller to achieve maximum transmission efficiency tracking control, according to the measured load voltage and current. Finally, simulations and experiments are adopted to verify the proposed coordinated control method. The experimental results indicate that the average system transmission efficiency is increased by 1.80% and the efficiency fluctuation is decreased by 2.67% when the system load resistance varies, while the average system transmission efficiency is increased by 1.80%, and the efficiency fluctuation is decreased by 3.14% when the mutual inductance changes. This means the proposed coordinated control method is effective under the conditions of the WPT load and mutual inductance variations.

Advancing Energy Sustainability Through Solar-to-Fuel Technologies: From Materials to Devices and Systems.

To achieve carbon neutrality and sustainable development, innovative solar-to-fuel systems have been designed through the integration of solar energy harvesting and electrochemical devices. Over the last decade, there have been notable advancements in enhancing the efficiency and durability of these solar-to-fuel systems. Despite the advancements, there remains significant potential for further improvements in the performance of systems. Enhancements can be achieved by optimizing electrochemical catalysts, advancing the manufacturing technologies of photovoltaics and electrochemical cells, and refining the overall design of these systems. In the realm of catalyst optimization, the effectiveness of materials can be significantly improved through active site engineering and strategic use of functional groups. Similarly, the performance of electrochemical devices can be enhanced by incorporating specific additives into electrolytes and optimizing gas diffusion electrodes. Improvements in solar harvesting devices are achievable through efficient passivant and self-assembled monolayers, which enhance the overall quality and efficiency of these systems. Additionally, optimizing the energy conversion efficiency involves the strategic use of DC converters, photoelectrodes, and redox media. This review aims to provide a comprehensive overview of the advancements in solar-powered electrochemical energy conversion systems, laying a solid foundation for future research and development in the field of energy sustainability.

A new high step-down soft-switched DC–DC converter based on coupled inductor

ABSTRACT This study introduces a new non-isolated DC–DC converter capable of achieving a high step-down conversion ratio. The design reduces switching losses through soft-switching, allowing switches to operate under Zero Voltage Switching (ZVS), which enhances efficiency. The converter employs a single coupled inductor without additional inductors in the power path, achieving low voltage gain and an extended duty cycle, resulting in reduced losses, lower costs, and optimal efficiency compared to similar topologies. Voltage stress on semiconductors is minimised by recycling leakage inductance energy to the output. The proposed converter achieves a greater step-down voltage gain per component compared to similar designs. Different operational modes and design aspects are examined. A prototype was constructed, and experimental results confirmed the theoretical analysis.

Bidirectional Power Sharing Control with Current-Fed Dual Active Bridge Converter: Hybrid Technique

This paper proposes a hybrid method for controlling bidirectional power sharing among grids and dc microgrids. The interlinking converter (IC) and current-fed dual active bridge (CFDAB) converters connect the grid and dc microgrid. The proposed approach is the joint implementation of golden eagle optimization and radial basis function neural network, hence, named the GEO-RBFNN approach. The bidirectional power distribution control signal analysis significantly diminishes power distribution deviation and circulating current. This power-sharing control system neglects the need for battery backup since the required amount of power is brought from or handled by an AC utility. The dc microgrid incorporates the dc to dc converter, from which boost converters use sources and buckconverters use supply loads. The control of bidirectional power sharing among the microgrids and the grid is attained with the aid of the GEO-RBFNN algorithm. It delivers certain aids, like higher predictability, highly reliable results, high speed, and less complexity. The outcome is investigated on the MATLAB platform. According to the comparison outcome, the proposed method delivers higher performance than the existing system. The proposed method gives higher comparison outcomes than the current methods, which can conquer the associated problems. The proposed method-based settling time is 3.356 ms, and the rise time is 1.555 ms. The efficiency based on the proposed method is 97.54%, which is higher than the existing methods.

Modelling and optimization of planar transformers for high power density step-down DC–DC converters

Modelling and optimization of planar transformers for high power density step-down DC–DC converters

A Hybrid RBFNN-SPOA Technique for Multi-Source EV Power System with Single-Switch DC-DC Converter

With a single-switched DC-DC converter, a hybrid approach is proposed for a fast-charging (FC) dc to dc converter with the controller for an electric vehicle charging station (EVCS) that combines solar photovoltaic (PV), fuel cells (FC), and a battery energy storage system (BESS). The proposed hybrid technique integrates a radial-basis-function-neural-network (RBFNN) and a student-psychology-optimization-algorithm (SPOA); commonly known as the RBFNN-SPOA technique. The PV-FC hybrid electric vehicle systems, like controllers, electric vehicle, and the vehicle’s power source, are displayed. The proposed converter architectures have less voltage waveform changes, a low voltage stress on semiconductor power sources, and a high-voltage ratio of conversion. The proposed method is to use FC successfully at battery charge states and varied radiation levels. The FC in the controller of SPOA may change the inputs and outputs depending on the battery state of charge (SoC) and PV irradiation. Similarly, the needed input-torque for the motor is forecasted by the recalling recurrent neural network controller using several manually produced torque signals. The performance of the proposed technique is evaluated in MATLAB and is compared to ant colony optimization (ACO), crow optimization algorithm (COA), and fuzzy logic controller (FLC) approaches. According to the results, the efficiency of the proposed technique is 99.17%.

An Isolated High Gain Push Pull Type DC to DC Converter for Fuel Cell Power Generation Systems

Due to their high efficiency and low environmental impact, fuel cell power generation systems have emerged as promising alternatives to traditional energy sources. However, the integration of fuel cells into practical applications necessitates the development of efficient power conversion systems. dc-dc converters play a crucial role in optimizing the power flow between the fuel cell stack and the load. In this paper, a push-pull type high gain dc-dc converter is proposed which consists of a push-pull inverter, a rectifier circuit, and C-filter. The push pull inverter produces high frequency square wave output while the full bridge rectifier and C-filter convert this square wave output into desired dc voltage. The converter boosts the 12V dc input supply to 326 V, representing a gain factor of more than 27. The isolated coupling inductor used in push pull inverter produces high gain and provides electrical isolation. Besides, the proposed topology eliminates the use of bulky grid-connected power transformers that decreases the system size and cost. To evaluate the performance of the proposed topology, a number of simulations under varying loads were carried out in the MATLAB Simulink framework. Further-more, a scaled-down prototype of 160W at 12/326 V was developed to confirm the simulation results. The findings indicate that the suggested converter can be a viable option for the hydrogen fuel cell-based power conversion system. GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 10(1), 2023 P 37-52

Design and implementation of an innovative single-phase direct AC-AC bipolar voltage buck converter with enhanced control topology

Direct AC–AC converters are strong candidates in the power converting system to regulate grid voltage against the perturbation in the line voltage and to acquire frequency regulation at discrete step levels in variable speed drivers for industrial systems. All such applications require the inverted and non-inverted form of the input voltage across the output with voltage-regulating capabilities. The required value of the output frequency is gained with the proper arrangement of the number of positive and negative pulses of the input voltage across the output terminals. The period of each such pulse for low-frequency operation is almost the same as the half period of the input grid or utility voltage. These output pulses are generated by converting the positive and negative input half cycles in noninverting and inverting forms as per requirement. There is no control complication to generate control signals used to adjust the load frequency as the operating period of the switching devices is normally greater than the period of the source voltage. However, high-frequency pulse width modulated (PWM) control signals are used to regulate the output voltage. The size of the inductor and capacitor is inversely related to the value of the switching frequency. Similarly, the ripple contents of voltage and currents in these filtering components are also inversely linked with PWM frequency. These constraints motivate the circuit designer to select high PWM frequency. However, the alignment of the high-frequency control input with the variation in the input source voltage is a big challenge for a design engineer as the switching period of a high-frequency signal normally lies in the microsecond. It is also required to operate some high-frequency devices for various half cycles of the source voltage, creating control complications as the polarities of the half cycles are continuously changing. This requires at least the generation of two high-frequency signals for different intervals. The interruption of the filtering inductor current is a big source of high voltage surges in circuits where the high-frequency transistors operate in a complementary way. This may be due to internal defects in the switching transistors or some unnecessary inherent delay in their control signals. In this research work, a simplified AC–AC converter is developed that does not need alignment of high-frequency control with the polarity of the source voltage. With this approach, high-frequency signals can be generated with the help of any analog or digital control system. By applying this technique, only one high-frequency control signal is generated and applied in AC circuits, as in a DC converter, without applying a highly sensitive polarity sensing circuit. So, controlling complications is drastically simplified. The circuit and configuration always avoid the current interruption problem of filtering the inductor. The proposed control and circuit topology are tested both in computer-based simulation and practically developed circuits. The results obtained from these platforms endorse the effectiveness and validation of the proposed work.

Design of low‐stress ultrahigh‐gain dc–dc converter with coupled inductor

AbstractThe 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.

An asymmetrical quadruple active bridge series resonant DC–DC converter for modular solid‐state transformers

AbstractThe DC–DC conversion stage of a three‐stage solid‐state transformer is the most challenging due to the combination of high power, medium voltage, and medium frequency. This combination also causes most of the losses in the DC–DC stage. To address this issue, a new asymmetrical quadruple active bridge series resonant DC–DC converter (AQAB‐SRC) has been proposed as a building block for solid‐state transformers. The converter achieves soft switching of all switches throughout the operating range by extending and using the half‐cycle continuous conduction mode control strategy. It also has fewer high‐frequency transformers compared to other converters, as more bridges are connected to the same multi‐winding transformer. The optimal design of AQAB‐SRC has been analyzed theoretically, and simulation and lab‐scale experimental results have been obtained to validate the feasibility and validity of the proposed topology.

Experimental validation of an analytical transient model for saturated boosting gain in DC–DC converters with variable duty cycle

This paper presents an innovative approach to characterize the boosting gain saturation phenomenon in DC–DC converters with variable duty cycles, a crucial component in energy management applications such as renewable energy systems and IoT devices. While existing literature predominantly relies on steady-state models to explain boosting gain behaviour, this study reveals discrepancies between theoretical predictions and experimental observations, particularly at high duty cycles. The research introduces an analytical model to accurately capture the boosting gain dynamics of a boost chopper converter, addressing the limitations of traditional steady-state analyses. Through experimental validation and numerical simulations using CAD tools, a significant boosting gain saturation of approximately 2.2 is empirically observed, highlighting the necessity for a transient model approach. By providing a comprehensive understanding of the boosting ratio constraints in practical boost converters, this work contributes to advancing the analytical modelling techniques in the field. The mathematical model’s validation through rigorous experimental measurements and simulation analyses underscores its reliability and applicability in real-world scenarios. The structured organization of the paper elucidates the development and verification process, culminating in insightful conclusions that underscore the significance of transient modelling in enhancing the performance and efficiency of DC–DC converters.