DC-DC Converter Configuration Research Articles

Conventional and Switched Capacitor Boost Converters for Solar PV Integration: Dynamic MPPT Enhancement and Performance Evaluation

This paper designs two DC-DC converter configurations integrated with solar PV renewable energy resource. Its focuses on comparing two converter topologies: the conventional boost converter and the switched capacitor boost converter. The Perturb and Observe (P&O), Incremental Conductance (INC), Genetic Algorithm (GA), and Particle Swarm Optimization (PSO) algorithms are employed to dynamically enhance the Maximum Power Point Tracking (MPPT) performance for both converters. The simulation results demonstrate that both converter topologies, when integrated with appropriate MPPT algorithms, can effectively harvest maximum power from the solar PV. However, the switched capacitor topology converter exhibits advantages in terms of current capabilities and voltage performance. In addition, combing the switched capacitor boost converter with the GA-MPPT algorithm improved the output voltage profile. The switched capacitor topology demonstrates distinct advantages by exhibiting enhanced current control, enabling improved handling of dynamic load changes and varying irradiance conditions. It shows voltage regulation, resulting in reduced output voltage fluctuations and enhanced stability, thereby optimizing energy extraction. The GA-MPPT simulation demonstrates a substantial increase in maximized output current for the switched capacitor boost configuration (70 A) when compared to the conventional type (10 A). The validation and implementation of the system models are carried out using MATLAB/Simulink.

Review of Electric Vehicle Charging Technologies, Standards, Architectures, and Converter Configurations

Electric Vehicles (EVs) are projected to be one of the major contributors to energy transition in global transportation due to their rapid expansion. High-level of EVs integration into the electricity grid will introduce many challenges for the power grid planning, operation, stability, standards, and safety. Therefore, the wide-scale adoption of EVs imposes research and development of charging systems and EV supply equipment (EVSE) to achieve expected charging solutions for EV batteries as well as to improve ancillary services. Analysis of the status of EV charging technologies is important to accelerate EV adoption with advanced control strategies to discover a remedial solution for negative impacts and to enhance desired charging efficiency and grid support. This paper presents a comprehensive review of EV charging technologies, international standards, the architecture of EV charging stations, and the power converter configurations of EV charging systems. The charging systems require a dedicated converter topology, a control strategy, compatibility with standards, and grid codes for charging and discharging to ensure optimum operation and enhance grid support. An overview of different charging systems in terms of onboard and off-board chargers, AC-DC and DC-DC converter configuration, and AC and DC-based charging station architectures are evaluated. In addition, recent charging systems which are integrated with renewable energy sources are presented to identify the power train of modern charging stations. Finally, future trends and challenges in EV charging and grid integration issues are summarized as the future direction of the research.

Use of Boost Power Stage for Static Voltage Gain Improvement of a Non-isolated Continuous Input Current Three-Level DC-DC Converter

The work presented in this paper describes the steady state analysis of a non-isolated and continuous conduction mode (CCM) operated three-level DC-DC converter with input boost power stage for achieving high static voltage gain. The proposed converter configuration is a double boost DC-DC conversion scheme. A boost power module consisting of a power switch, an inductor, a pre-charge diode, and a diode rectifier is introduced as the input stage in the conventional three-level DC-DC converter configuration to obtain the DC-DC converter topology suggested in this research work. The role of the input boost power stage is to extend the voltage gain of the conventional three-level boost converter. The proposed topology employs two power switches in addition to a boost power switch with simple control strategy so that the switching losses are reduced. The switches are subjected to low voltage and current stresses. The suggested non-isolated converter is operated under continuous inductor current mode in open loop configuration. The converter configuration has been simulated in MATLAB / SIMULINK platform. The input boost power stage receives a voltage of 24 V from a DC source. With low duty ratio (= 0.8) of the power switches, a DC voltage of around 208 V is obtained at the load end. The passive components of the converter are so designed that the filtering requirements on the DC output voltage and current waveforms are reduced. The voltage gain of the proposed converter is compared with that of the three-level boost converter without input boost power stage. The various modes of operation of the suggested converter are discussed with relevant equivalent circuits. The proposed system is validated using a developed hardware prototype model of 100 W converter with a low cost KA3525A PWM controller. Both simulation and prototype model results demonstrate that the proposed converter suits high voltage gain applications.

Design and Implementation of Bipolar Sepic-Cuk Converter with Fuzzy Logic Control for Battery Charging Application

This research presents the design of an electricity distribution system with a solar cell source that is applied to the battery charging process. The charging setting uses a modified DC-DC converter configuration from the modified Sepic and Cuk converters. With one Bipolar Sepic-Cuk Converter voltage source produces two outputs of the same voltage value with different polarities. The method applied is constant voltage, where the voltage generated by the solar panel will always be constant and the same in accordance with the setpoint specified in the charging process. The control used is a fuzzy logic control that functions to regulate the PWM output signal by getting the duty cycle value. The voltage sensor is used as feedback from the control to be processed by the microcontroller so as to produce a PWM signal which will be used to regulate switching on the Bipolar Sepic-Cuk converter circuit. The output voltage of the converter has been achieved with fuzzy control with irradiation and temperature variations. The results of the output voltage can be maintained at a predetermined voltage. The error percentage of the generated voltage is equal to 0.14 - 0.5%.

Control analysis of parallel DC-DC converters in a DC microgrid with constant power loads

This paper proposes a general methodology for designing hierarchical control schemes for DC microgrids loaded by constant power loads. This paper addresses issues when interfacing sources with a wide voltage range allowing for any general choice for a power source. The control strategy consists of two levels. The lower level consists of droop-based primary controllers. This controller enables current-sharing among paralleled sources and also damps limit cycle oscillations due to constant power loads. The higher level is a secondary controller which compensates for voltage deviations due to primary controller and performs voltage control of the microgrid. It also maintains the current sharing obtained in the primary stage. In the proposed secondary control, high-speed communication links to the primary controllers is implemented. The stability conditions are explained using the equivalent circuit of converters. Using this approach, stability conditions can be derived for microgrids of an arbitrary size and converter topology. The proposed control scheme is shown to be scalable and robust. The results obtained for the three basic DC-DC converter configurations are compared based on a microgrid with a parallel configuration of buck-boost converters. Simulations and experimental results are presented to verify the validity of the proposed control schemes.

Step-Down DC-DC Converter Using Coupled-Inductors and Passive Clamped Circuit

A novel step-down DC-DC converter configuration is adopted in this paper. The new converter makes use the closed inversely coupled inductors topology. The proposed technique targeting the suppression of high content of switching noise that commonly accompanies the stepping-down converter circuits. This can be achieved by restraining the induced back electromotive force in the prime inductor. The induced back electromotive force is a result of discontinuous flow of line current in the prime inductor. The proposed technique preserves an uninterrupted stream of line current through-out the prime inductor which results in a considerable depression in the induced back electromotive force and consequently minimises the switching noise and enhancing the power conversion efficiency. A unique design of passive clamped circuit using coupled inductors is also proposed in this converter architecture. The leakage energies of the prime and the coupled-inductors can be recycled using the new passive clamped circuit and the captured energy can be then transferred to the load side alongside with the source or input energy. As a result, an efficiency improvement of the new converter can be achieved and the voltage stress on the power switches and diodes can be reduced. Circuit configuration, principles of operation and the transfer function of the new converter are figured out. The proposed concept of the new conversion technique is verified by the experimental and the simulated results of a range of case studies.

A Negative Embedded Differential Mode Γ-Source Inverter With Reduced Switching Spikes

Magnetically coupled impedance source networks (MCIS) are capable of producing higher voltage gains at the expense of high switching voltage spikes due to the presence of leakage inductance. These voltage spikes decorate the converter efficiency and life expectancy of switches. Therefore, to reduce the voltage spikes, a negative embedded differential mode gamma source inverter (NEDM ${{\Gamma }}$ ZSI) is presented in this brief. The proposed inverter can achieve higher voltage gains with reduced switching voltage spikes and low capacitor voltage stresses compared to other MCIS networks. Also, the proposed inverter draws continuous input current from the dc mains, having a common ground, and uses the minimum number of component in a circuit. The operating principle of the proposed NEDM ${{\Gamma }}$ ZSI is analyzed in electrical and magnetic domains. The ability of the proposed impedance network, in terms of voltage spike suppression has been verified experimentally using DC-DC converter configuration. Finally, the performance of a NEDM ${{\Gamma }}$ ZSI is validated with simulation and experimental verification using a single-phase inverter configuration.

A Modular Multilevel DC–DC Converter With a Compact Sub-Module Stack Suited to Low Step Ratios

The voltage ratings for dc transmission and distribution are not currently standardized because cable technology is advancing rapidly and therefore a low step-ratio dc-dc converter at multi-megawatt scale is a crucial technology for combining point-to-point dc links into multi-terminal networks. This paper presents a modular multilevel dc-dc converter configuration with only a single stack of half-bridge sub-modules (SM) and a resonant tank. The power processed through the stack is a small fraction of the throughput power if the step ratio is small (1 - v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">L</sub> /v <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">H</sub> ). Detailed analysis shows the required semiconductor ratings are much smaller compared to the front-to-front MMC and modular converters derived from standard dc-dc topologies. Further, the requirement for SM capacitive energy storage is also significantly less than those converters. The theoretical analysis and the operating principles have been verified by full-scale simulation examples and experiments with a down-scaled prototype. The SMs are operated with an adjustable phase shift to create a high frequency excitation across the resonant tank for further volume reduction. The SM capacitors self-balance without the need for switching pattern adjustments and the resonant operation provides soft switching for all power switches to increase efficiency.

Multi Bus DC-DC Converter in Electric Hybrid Vehicles

This paper is cotncerned with the design, simulation and fabrication of the prototype of a Multi bus DC- DC converter operating from 42V DC and delivering 14V DC and 260V DC. As a result, three DC buses are interconnected through a single power electronic circuitry. Such a requirement is energized in the development of a hybrid electric automobile which uses the technology of fuel cell. This is implemented by using a Bidirectional DC-DC converter configuration which is ideally suitable for multiple outputs with mutual electrical isolation. For the sake of reduced size and cost of step-up transformer, selection of a high frequency switching cycle at 10 KHz was done.

DC-Transformer Modelling, Analysis and Comparison of the Experimental Investigation of a Non-Inverting and Non-Isolated Nx Multilevel Boost Converter (Nx MBC) for Low to High DC Voltage Applications

This paper mainly focuses on the analysis, DC-transformer modeling, comparison, and experimental investigation of a non-inverting and non-isolated Nx multilevel boost converter (Nx MBC) for low to high DC applications. Recently, numerous isolated and non-isolated DC-DC converter configurations have been addressed for low to high DC voltage conversion purposes, which is vital for several applications (e.g., renewable energy, medical equipment, hybrid vehicles, fuel cells, DC-links, multilevel inverters, and drive applications), by utilizing and modifying the structure of reactive elements (switched capacitors and switched inductor circuitry). Among all the switched reactive structures, voltage multiplier circuitry provides a feasible solution for low to high DC voltage conversion due to its flexible and modular structure, voltage clamping capability, reduced rating of components, and ease of modification. Non-inverting and non-isolated Nx MBC combine the features and structures of conventional boost converters and voltage multiplier circuitry. DC-transformer modeling of Nx MBC is discussed for the continuous current mode (CCM) and discontinuous current mode (DCM), which helps to analyze the characteristics of the converter in a more practical way and helps to study the effect of semiconductor components, internal resistances, and load on the voltage conversion ratio of the converter. The mode of operation of Nx MBC in the CCM and DCM is also discussed with the boundary condition. The derived analysis is verified by simulations and experimental investigations, and the obtained results of 3x MBC always show good agreement with each other and the theoretical analysis.

Interleaved Boost Converter Fed with PV for Induction Motor/Agricultural Applications

In present Electricity market Renewable Energy Sources (RES) are gaining much importance. The most common Renewable Energy Sources are Photo voltaic (PV), fuel cell (FC) and wind energy systems, out of these three PV systems PV system can implemented in most of the locations. Due to the power cuts and power disturbances in Distribution systems agriculture application is concentrated on PV based Energy system. The use of PV system is increasing day by day in agriculture application, due to their ease of control and flexibility. PV Electrification schemes also involves various subsidies in government national and international donors. Especially in Agriculture field by use of PV one can achieve higher subsidy. The output of PV system is low voltage DC to have high efficiency. The motors used in agriculture field are Induction Motors (IM) fed from Three phase AC supply, to boost the PV output we need a high voltage gain boost converter along with PWM inverter to Induction motor drive. Out of various DC-DC converter configurations interleaved boost converter is gaining much attention, due to its reduction in size and Electromagnetic Interference (EMI). In this work we are proposing a PV fed interleaved boost converter with PWM inverter for agriculture applications. The design process of interleaved boost converter is explain detail and compared with existing boost converter. A 10KW Power rating is choosing for the Induction motor drive and design calculations are carried out. A MATLAB/SIMULINK based model is developed for boost and interleaved boost converter and simulation results are presented, finally a scaled down hardware circuit design for interleaved boost converter and results are presented.

New Single-Input, Multiple-Output Converter Topologies: Combining Single-Switch Nonisolated dc-dc Converters for Single-Input, Multiple-Output Applications

This article presents a methodology that allows the development of new converter topologies for single-input, multiple-output (SIMO) from different basic configurations of single-input, single-output dc-dc converters. These typologies have in common the use of only one power-switching device, and they are all nonisolated converters. Sixteen different topologies are highlighted, and their main features are explained. The 16 typologies include nine twooutput-type, five three-output-type, one four-output-type, and one six-output-type dc-dc converter configurations. In addition, an experimental prototype of a three-output-type configuration with six different output voltages based on a single-ended primary inductance (SEPIC)-Cuk-boost combination converter was developed, and the proposed design methodology for a basic converter combination was experimentally verified.

A Converter for Bipolar DC Link Based on SEPIC-Cuk Combination

This letter describes a new application of single-ended primary converter (SEPIC) and Cuk converter for dc bipolar network. A dc-dc converter configuration based on a combination of both converters is proposed. In the resulting topology, the switching node is shared by the SEPIC and Cuk converter since they have the same instantaneous duty cycle. The main advantage of this topology is that synchronization of various switches is not required and control terminal is connected to ground which simplifies the design of the gate drive. On the other hand, this configuration allows the connection of renewable energy sources to microgrids (MG)-type bipolar dc link and to cover the current needs of new distributed generation units with efficient, economical, and easy way. To verify its performance, a prototype was designed. Experimental results show as this combination of two converter topologies with appropriated modulation schemes are adequate to use in dc MG.

A Novel Switched-Coupled-Inductor DC–DC Step-Up Converter and Its Derivatives

This paper presents a novel dc-dc converter configuration, which successfully integrates two technologies, including a switched capacitor and a switched coupled inductor, into one converter. By adopting a coupled inductor to charge a switched capacitor, the voltage gain can be effectively increased, and the turns ratio of the coupled inductor can be also reduced. Not only lower conduction losses but also higher power conversion efficiency is benefited from a lower part count and lower turns ratios. The proposed converter is simply composed of six components, which can be further derived to varied converters for different purposes, such as a bidirectional converter. The operating principle and steady-state analysis are discussed in this paper. A 250-W laboratory hardware prototype is completed and verified. The voltage gain is up to 11. The highest efficiency is 97.2%, and the full-load efficiency is kept at 93.6%.

A Multilevel Active-Clamped Converter Topology—Operating Principle

This paper presents a novel multilevel active-clamped converter topology, which is an extension to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> levels of the three-level active neutral-point-clamped topology. The operating principle is established through the definition of a proper set of switching states and a transition strategy between adjacent switching states. The benefits of the proposed converter topology and control in comparison to alternative multilevel converter topologies are discussed. The simulation and experimental results of a simple four-level dc-dc converter configuration are presented to illustrate the converter performance features. The experimental results of a four-level three-phase dc-ac converter are also presented to further validate the proposed topology and operating principle.

Comparison of Total Losses of 1.2 kV SiC JFET and BJT in DC-DC Converter Including Gate Driver

The 1.2 kV SiC JFET and BJT devices have been investigated and compared with respect to total losses including the gate driver losses in a DC-DC converter configuration. The buried grid, Normally-on JFET devices with threshold voltage of -50 V and -10V are compared to BJT devices with ideal semiconductor and passivating insulator interface and an interface with surface recombination velocity of 4.5•104 cm/s yielding agreement to the reported experimental current gain values. The conduction losses of both types of devices are independent of the switching frequency while the switching losses are proportional to the switching frequency. The driver losses are proportional to the switching frequency in the JFET case but to a large extent independent of the switching frequency in the BJT case. The passivation of the emitter junction modeled here by surface recombination velocity has a significant impact on conduction losses and gate driver losses in the investigated BJT devices.

DC–DC Converter-Aware Power Management for Low-Power Embedded Systems

Most digital systems are equipped with dc-dc converters to supply various levels of voltages from batteries to logic devices. DC-DC converters maintain legal voltage ranges regardless of the load current variation as well as battery voltage drop. Although the efficiency of dc-dc converters is changed by the output voltage level and the load current, most existing power management techniques simply ignore the efficiency variation of dc-dc converters. However, without a careful consideration of the efficiency variation of dc-dc converters, finding a true optimal power management will be impossible. In this paper, we solve the problem of energy minimization with the consideration of the characteristics of power consumption of dc-dc converters. Specifically, the contributions of our work are as follows: 1) We analyze the effects of the efficiency variation of dc-dc converters on a single-task execution in dynamic voltage scaling (DVS) scheme and propose the technique for dc-dc converter-aware energy-minimal DVS. 2) is then extended to embed an awareness of the characteristics of dc-dc converters in general DVS techniques for multiple tasks. 3) We go on to propose a technique called for generating a dc-dc converter that is most energy efficient for a particular application. 4) We also present an integrated framework, i.e., , based on and , which addresses dc-dc converter configuration and DVS simultaneously. Experimental results show that is able to save up to 24.8% of energy compared with previous power management schemes, which do not consider the efficiency variation of dc-dc converters.