Converter Topology Research Articles

ANALYSIS OF BIDIRECTIONAL DC-DC POWER CONVERTERS FOR SCREENING SYSTEMS OF RETIRED BATTERIES

With the rapid expansion of energy storage technologies, the concept of the second-life battery has become a central element in sustainability and energy efficiency efforts. This innovative approach refers to the further use of batteries, which have reached the end of life, integrating them into applications with lower energy requirements than those in the automotive industry. The batteries must first be evaluated using a screening system that contains a power converter to apply different test profiles and a measurement and control circuit. This article outlines key performance considerations of bidirectional DC-DC power converter topologies and compares them using multi-criteria analysis to determine which design is more suitable for screening systems. The chosen power converters are further studied in the LTspice program for a detailed comparison based on the obtained results.

Comparison of Configurable Modular Two-Level and Three-Level Isolated Bidirectional DC–DC Converters for Super-Capacitor Charging in DC Shore Power Systems

Compared to the AC counterpart, the DC shore power system provides a significant advantage of efficient power supply from renewable sources to ships and onshore loads. Super-capacitors serve as key energy storage units in such a system to buffer the power fluctuations and collect the regenerative energy. However, the ultra-wide voltage range of super-capacitors imposes a significant challenge in the topology selection and efficiency optimization of the interfacing isolated bidirectional DC–DC converter. To tackle this challenge, this paper analyzes and compares two promising converter topologies, which are a configurable modular two-level dual-active bridge (CM-2L-DAB) and a three-level dual-active bridge (3L-DAB). To facilitate an ultra-wide voltage range, extended phase-shift (EPS) modulation in conjunction with the topology reconfiguration is analyzed for the CM-2L-DAB, while a hybrid modulation scheme is proposed for the 3L-DAB. A unified design approach is provided for both topologies, which also yields to the power loss modeling. On this basis, the CM-2L-DAB and 3L-DAB are thoroughly compared in terms of the modulation schemes, current stress, soft-switching operation, power conversion efficiency, material usage, closed-loop control scheme, and reliability. A prominent conclusion can be drawn that the CM-2L-DAB provides a higher efficiency than the 3L-DAB over the whole voltage range, but it relies on additional relays to reconfigure its topology which results in lower reliability and dynamic performance than the 3L-DAB.

A Novel Modular Multilevel Converter Topology with High- and Low-Frequency Modules and Its Modulation Strategy

To resolve the issue of the difficultly in effectively balancing the output performance improvement, cost reduction, and efficiency improvement of a medium-voltage modular multilevel converter (MMC), a novel MMC (NMMC) topology based on high- and low-frequency hybrid modulation is proposed in this study. Each arm of the NMMC contains a high-frequency sub-module composed of a heterogeneous cross-connect module (HCCM) and N − 1 low-frequency sub-modules composed of half-bridge converters. The high-frequency bridge arm of the HCCM in this study adopts SiC MOSFET devices, while the commutation bridge arm and low-frequency sub-module of the HCCM adopt Si IGBT devices. For the NMMC topology, this study adopts a high/low-frequency hybrid modulation strategy, which gives full play to the advantages of low switching loss in SiC MOSFET devices and low on-state loss in Si IGBT devices. In addition, a specific capacitor voltage balance strategy is proposed for the HCCM, and the working state of the HCCM is analyzed in detail. Furthermore, the feasibility and effectiveness of the proposed topology, modulation strategy, and voltage balancing strategy are verified by experiments. Finally, the proposed topology is compared with the existing MMC topology in terms of device cost and operating loss, which proves that the proposed topology can better balance the cost and efficiency indicators of the device.

Current-Mode Control of a Distributed Buck Converter with a Lossy Transmission Line

This article presents a buck converter in which the inductor has been replaced by a transmission line. This approach would be practically conceivable if the power supply and load had a greater spatial distance. Alternatively, the model derived in this way could also be regarded as an intermediate model in order to replace a power coil via discretization with a larger number of smaller coils and capacitors. In the time domain, this new converter can be described by a system of coupled partial and ordinary differential equations. In the frequency domain, a transcendental transfer function is obtained. For comparison with an equivalently parameterized conventional converter, Padé approximants are derived. A linear controller is designed for the converter topology under consideration.

A high efficiency boost converter topology with least component count

<p class="IEEEAbtract">This paper presents a design and analysis of novel DC-DC boost converter with a least component count. The proposed converter produces high DC gain voltage in comparison to some recently presented high voltage DC-DC converter. Here one switch, one inductor, two capacitors and one diode are used to achieved a high voltage gain without compromising efficiency of converter. The converter’s performance is evaluated using theatrical, simulation and experimental methods, with results indicating a four times of input voltage and a fast-transient response at various duty cycles is achieved. Due to its low component count the proposed converter is compact and hence it offers an effective solution for various power applications.</p>

State of-The-Art Multi-Input DC-DC Converter Topologies and their Control Techniques: A Review

Environmental awareness and technological advancement have made renewable energy sources such as fuel cell,solar photovoltaic (PV), wind energy an emerging research area. Power electronics converters are used as interface betweenthe renewable energy sources and the load unit, aimed at matching these sources with the load demand and improving thesteady-state and dynamic characteristics. Traditional method of using multiple single-input single-output dc-dc converter tointegrate several renewable energy sources, comes with challenges in controller design, poor efficiency, low power densityand increase in cost. To address these limitations, the use of an integrated multi-port converter is a preferable solution.Recently, several multi-port dc-dc converter topologies have been reported each having its peculiarity in terms of number ofcomponent count, relationships between input and output, voltage conversion ratio, control algorithm and efficiency. Thisarticle reviewed multi-port dc-dc converters presented by different research groups from the point of view of topology, inputand output relation and structure. Furthermore, control algorithms proposed to solve various control problems are alsoreviewed.

An Enhanced Voltage Gain Techniques in Quadratic Boost Converters - A Systematic Review

High voltage gain non-isolated boost DC-DC converters are widely employed in applications such as hybrid electric vehicles, aircraft power supplies, photovoltaic (PV) systems and fuel cells (FC) applications. The use of conventional boost converters in high-gain applications is affected by their practical limitation on their voltage gain. Several boost converter topologies based on different voltage lift techniques have been studied and reported; them is quadratic boost converter (QBC). These converters have recently emerged as an interesting topology because of the quadratic nature of their voltage gain, simple among structure and simple control scheme. Recently modified topologies of QBC employing different voltage lift techniques aimed at further enhancing their performance are reported. This paper is aimed at presenting a review on the advances in quadratic boost converters topologies. In this article, QBC are categorized into five groups: magnetically coupled based on coupled-inductor (CI), switch-inductor (SI), switch-inductor switch-capacitor (SC-SI), switch-capacitor (SC), and soft-switching QBC. Furthermore, the paper makes a comprehensive comparison of various QBC in terms of voltage conversion ratio, total component count, input current ripples and voltage stress across switching devices.

Research on the energy transmission mode of a three-port DC–DC converter based on ultra-thin silicon steel

With the introduction of China’s “Carbon Peaking Action Plan Before 2030,” the transformation of the power industry has released huge opportunities and potential. The DC distribution network can well-coordinate the contradiction between distributed power and grid access, fully develop the benefits of distributed energy, and become a new direction for the development of the power industry. However, the current traditional DC–DC converters have problems such as single-topology structure and low power density, which can only complete one-way transmission of energy; hence, the distributed energy cannot be fully utilized. Addressing the problem of distributed energy transfer, this paper is based on a three-port DC–DC converter for a low-voltage DC distribution network to realize energy transfer between the DC distribution network, distributed energy, and low-voltage load. First, the energy transfer modes of the three-port DC–DC converter are introduced. Combined with the converter topology and energy transfer mode, a simplified equivalent model of the converter is established. The voltage gain characteristics and frequency characteristics of this converter are studied. Furthermore, the effects of the excitation inductance to primary resonance inductance ratio parameter k and quality factor Q on the voltage gain characteristics of the converter are discussed. On this basis, the resonant cavity design of the converter is based on the optimal selection of parameters k and Q so that the converter can meet the voltage gain requirements in both forward and reverse operations. The simulation results under different loads verify the reasonableness of the resonant cavity component selection.

Performance comparison between PID and Fuzzy logic controllers for the hardware implementation of traditional high voltage DC-DC boost converter

This research introduces a hardware implementation of DC-DC boost converter designed to elevate the DC voltage generated by renewable sources while effectively regulating it against line and load fluctuations for inverter application. The main objective is to boost the DC link voltage to the level of Vmax in the output AC voltage obtained from inverter circuits. This enables the inverters for transformer-less power conversion from DC to AC to reduce magnetic losses, size and weight of the inverter circuits used in the utility application. The proposed converter's topology and switching sequences play a crucial role in enhancing overall performance. Utilizing a Zero Current Switching (ZCS) technique, the converter efficiently recovers stored energy from the magnetics. The proposed converter attained the output voltage of 350 V at its current of 1A from the input voltage of 20 V at its current of 19 A. The ZCS technique and the topology of the converter enhances the efficiency to 92 %. The study employs traditional Proportional-Integral (PI) and Proportional-Integral-Derivative (PID) controllers for effective voltage regulation, analysing time domain specifications. Additionally, a Fuzzy logic controller is introduced as an alternative to PID controllers to compare their performance metrics, evaluating the optimization of the converter's transient and steady-state behaviours. The proposed converter is designed, simulated and their performance metrics are analysed using MATLAB for both with and without controllers. The step-time characteristics of the proposed converter with load resistance of RL = 500 Ω and an input voltage of Vi = 20 V has been determined and analysed. The PID system attained a rise time of 88.781 ms, an overshoot value of 9.341 %, and a steady-state error of 0.00043. The fuzzy system achieved a low-rise time of 10.624 ms, a low overshoot of 0.55 %, and a steady-state error of 0.0584. The hardware prototype of the proposed converter is implemented with a FPGA based PID and Fuzzy logic controllers for providing better voltage regulation and to improve the performance metrics of the converter. The simulation and experimental findings are contrasted, examined, and confirmed to ensure improved consistency in performance measures.

A review of single stage and multistage power converters for doubly fed induction generator integrated with power grid

The doubly fed induction generator (DFIG) is the most popular induction generator for onshore wind energy conversion system (WECS). Therefore, the purpose of research is to optimize power transfer from DFIG to power grid which requires frequency and voltage stability in power converters. Hence, the single-stage and multistage power converter topologies associated with grid-integrated DFIG are thoroughly examined in this work. In the single stage, a matrix converter and cycloconverter are used. Whereas, the multistage topologies include two-level back-to-back (2L-B2B) converter, Z-source converter, and multilevel converters. Furthermore, three-level neutral point clamped (3L-NPC) voltage source converters with battery energy storage systems (BESS) and modified superconducting fractional order terminal sliding mode controllers (MSTFOTSMC) have been used with multilevel converter both at rotor side converter (RSC) and grid side converter (GSC) for stabilized generated voltage and higher power output. The MATLAB simulation results demonstrate that the system effectively controls fluctuations in voltage and current thereby improving the power quality in unbalanced situations.

Comparative Study of Multilevel Converters using DQ Current Control

This paper presents a comprehensive comparative analysis of different multilevel converter topologies, including 2-level, Neutral Point-Clamped (NPC), Cascaded H-Bridge (CHB), and T-Type converters using the DQ current control strategy. The study aims to evaluate the performance of these topologies concerning current Total Harmonic Distortion (THD) and ripple in the direct and quadrature components of the current. A mathematical model of the grid is presented to facilitate the simulation study. The DQ current control scheme is implemented to regulate the current in both the direct and quadrature axes. The simulations are conducted under various operating conditions to capture the converters’ performance across different load scenarios and modulation techniques. Results indicate significant variations in the performance metrics among the different converter topologies. The 2-level converter exhibits higher THD and ripple compared to the more complex multilevel topologies.

Research and economic evaluation on novel pulse superconducting magnet power supply topology with energy storage for fusion devices

Large capacity fusion devices power supply poses a significant challenge to the stability of power grid, as it can lead to power outages and jeopardize the safety of fusion devices. And traditional distribution methods result in a significant waste of resources. This paper proposes novel topologies with integrated energy storage. In these topologies, high-amplitude pulsed power is supplied by the energy storage devices, while low-amplitude stable power is obtained from the grid. This decouples the pulsed power from power grid, and significantly reducing its impact. Moreover, it can reduce the design capacity of distribution equipment and lowers investment costs. To optimize the deployment of the energy storage device, a hybrid topology is proposed, which further reducing the cost of the novel power supply. Additionally, a cost model for the fusion power supply is developed and validated using simulation data from ITER. Through the case study shows that the HEPS topology saves more than 10 % of the investment cost and about 60 % of the annual operating cost compared to the traditional converter topology.

A Deep Reinforcement Learning Approach to DC-DC Power Electronic Converter Control with Practical Considerations

In recent years, there has been a growing interest in using model-free deep reinforcement learning (DRL)-based controllers as an alternative approach to improve the dynamic behavior, efficiency, and other aspects of DC–DC power electronic converters, which are traditionally controlled based on small signal models. These conventional controllers often fail to self-adapt to various uncertainties and disturbances. This paper presents a design methodology using proximal policy optimization (PPO), a widely recognized and efficient DRL algorithm, to make near-optimal decisions for real buck converters operating in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) while handling resistive and inductive loads. Challenges associated with delays in real-time systems are identified. Key innovations include a chattering-reduction reward function, engineering of input features, and optimization of neural network architecture, which improve voltage regulation, ensure smoother operation, and optimize the computational cost of the neural network. The experimental and simulation results demonstrate the robustness and efficiency of the controller in real scenarios. The findings are believed to make significant contributions to the application of DRL controllers in real-time scenarios, providing guidelines and a starting point for designing controllers using the same method in this or other power electronic converter topologies.

An interleaved converter topology and optimized controller for electric vehicle drive utilizing solar photovoltaic system

An interleaved converter topology and optimized controller for electric vehicle drive utilizing solar photovoltaic system

A Novel Non-Isolated Bidirectional DC-DC Converter with Improved Current Ripples for Low-Voltage On-Board Charging

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

Non-Ideal Push–Pull Converter Model: Trade-Off between Complexity and Practical Feasibility in Terms of Topology, Power and Operating Frequency

Power converters are the basic elements of any power electronics system in many areas and applications. Among them, the push–pull converter topology is one of the most widespread due to its high efficiency, versatility, galvanic isolation, reduced number of switching devices and the possibility of implementing high conversion ratios with respect to non-isolated topologies. Optimal design and control requires very accurate models that consider all the non-idealities associated with the actual converter. However, this leads to the use of high-order models, which are impractical for the design of model-based controllers in real-time applications. To obtain a trade-off model that combines the criteria of simplicity and accuracy, it is appropriate to assess whether it is necessary to consider all non-idealities to accurately model the dynamic response of the converter. For this purpose, this paper proposes a methodology based on a sensitivity analysis that allows quantifying the impact of each non-ideality on the converter behaviour response as a function of the converter topology, power and frequency. As a result of the study, practical models that combine the trade-off between precision and simplicity are obtained. The behaviour of the simplified models for each topology was evaluated and validated by simulation against the most complete and accurate non-ideal model found in the literature. The results have been excellent, with an error rate of less than 5% in all cases.

A Reconfigurable Phase-Shifted Full-Bridge DC–DC Converter with Wide Range Output Voltage

This paper analyzes, designs and implements a reconfigurable phase-shifted full-bridge (PSFB) converter. It adopts the topology of the traditional PSFB converter and incorporates clamping circuits to solve some fundamental problems of conventional topology. In addition, auxiliary switches are employed for output reconfiguration, which allows expanding the output voltage range without compromising the system efficiency. Single pole double throw (SPDT) mechanical switches are used to realize series and parallel connections. In this paper, the characterization of the PSFB converter with clamping circuit and its design considerations are discussed. A 10 kW prototype with a power density of 0.485 W/cm3, 900 V input voltage and 400/800 V nominal output voltage was manufactured. The experimental results validated the analysis and confirmed the high conversion efficiency for a wide load range; an efficiency of 96.69% was obtained for the full load condition.

Advanced control of split source inverter through finite control-set model predictive control for improved system performance.

Distributed power generation systems may necessitate connecting multiple independent energy sources that employ various converter topologies. A recent development in this field is the emergence of impedance source converters, offering the ability to deliver buck-boost functionality within a single stage. The split-source inverter (SSI) has been introduced as a novel choice in between this family. Many control strategies have emerged for electrical power systems control. Among the recent emerging controllers, model predictive control strategies have become an effective technique for control systems. Model predictive controllers (MPCs) offer a number of features compared to the conventional and counterpart models such as enhanced system response and improved system transients with reduced steady-state error. This research suggests a finite control-set MPC for three-phase single-stage SSI supporting a standalone load for remote area applications. Considering the proposed FCS-MPC, the output load current tracks its reference magnitude with minimized error. In addition, the proposed FCS-MPC enhances the proposed SSI system performance with a settling time of 10 μs, and approximately without overshoot in the output current. The system has been validated using Opal-RT OP-4510 and the power loss model of the inverter has been explained. In the end two comparisons have been presented to clarify the main points in the topology structure and the control technique.

AMÉLIORATION DE LA CORRECTION DU FACTEUR DE PUISSANCE DANS UN CONVERTISSEUR AC-DC AVEC UN CIRCUIT BOOST-FLYBACK INTÉGRÉ

Due to advancements in semiconductor technology, modern controllers, and nonlinear characteristics, loads are increasingly used in industrial applications. Because of nonlinear traits, harmonics are introduced in the main supply, and the supply current is distorted. Numerous power factor correction (PFC) converter topologies are established for proper wave shaping. The integration of conventional PFC converters produces superior results in high voltage on the output side and improves efficiency. A single-stage boost flyback integrated PFC converter is investigated in this paper, which provides high efficiency, high output voltage, and less voltage stress. This converter uses a lesser number of components, which results in a compact size and low cost. The enhancement of power factor, efficiency, and wave shaping of the current waveform is realized through various control techniques. A novel current sensorless control for the integrated topology is investigated, and it is shown that it provides better total harmonic distortion and current wave shaping than other control techniques. A 48 W, 12/48 V prototype model is implemented to validate the simulation results practically.

Experimental Investigation of Modified Level Shift PWM with Capacitor Voltage Balancing on Single Phase Modular Multilevel Converter

Modular Multilevel Converters (MMCs) are a prominent voltage source converter topology that is rapidly gaining popularity in medium/high power/voltage applications, including high-voltage DC transmission systems and electric vehicle systems. However, MMC has the critical issue of unbalanced submodule capacitor voltages and circulating current. The MMC distributes DC-link energy evenly among its submodule capacitors, rather than storing it in a large capacitor like conventional voltage source converters. In MMC, the submodule floating capacitors interface the DC input voltage and AC output voltage. Therefore, capacitor voltages must be balanced. The existing capacitor voltage control struggles to handle many gate pulses at medium and high voltages. An effective control scheme is needed to solve the issues mentioned earlier. This paper presents a performance analysis of a 1-Φ MMC using a modified level shift PWM technique based on Universal Control Modulation Scheme (UCMS) and a sorting-based capacitor voltage balancing algorithm. MATLAB/Simulink software implements the proposed control method for a 1-Φ , seven-level MMC. The outcomes of the simulation demonstration reveal that phase disposition PWM offers less harmonic distortion of output phase voltage than the other level shift PWM techniques, such as phase disposition PWM and alternate phase disposition PWM. The simulation results also demonstrate the effective use of the sorting-based capacitor balancing algorithm to regulate the voltages of the submodule capacitors. Finally, the real-time GUI tool validates the simulation results using an experimental prototype of 1-Φ MMC with the dSPACE MicroLabBox 1202.