High Voltage Conversion Research Articles

Isolated High-Gain DC-DC Converter with Nanocrystalline-Core Transformer: Achieving 1:16 Voltage Boost for Renewable Energy Applications

This paper presents an isolated DC-DC converter with high voltage gain that features an advanced inter-built nanocrystalline-core medium-frequency transformer (NC-MFT). The isolated DC-DC converter with an NC-MFT is specifically designed for applications such as interconnect photovoltaic (PV) systems, DC microgrids, DC loads, and DC buses, where voltage gain is one of the essential issues to consider. The NC-MFT inside the DC-DC converter is designed with a new approach that not only provides isolation but also contributes to achieving high efficiency and a higher step-up ratio. The high efficiency of the converters contributes to the integration of PV systems into DC microgrids. The converter yields a high voltage conversion ratio of 16.17. The experimental results obtained at 41.8 V/676 V and 275 W for the prototype revealed high efficiency (95.63% at full load). The experimental results validate the theoretical analysis and simulation, confirming that the converter achieves the main objective of high voltage conversion and high efficiency. These results will contribute to the interest in the use of this type of energy and its impact on the reduction in CO2 emissions.

Design and Analysis of a Novel Bidirectional DC‐DC Converter With Ultra‐Conversion Ratio and Reduced Current Stress

ABSTRACTConventional nonisolated bidirectional DC‐DC converters are limited because of their low conversion voltage ratio. To overcome the limitation, this paper proposed a new bidirectional DC‐DC converter to introduce the novel regenerative configuration merged with the switched inductor technique for high voltage conversion applications. This design enables extreme DC‐voltage conversion with a minimal number of semiconductors and passive components. As a result, the converter's cost is reduced, and it can attain a high voltage gain with less duty ratio. In general, ultra‐gain converters suffer from high current stress across the input and output side switches in the step‐up and step‐down modes. To reduce high current stress, an active network configuration is imposed in the proposed converter. This paper describes the operating principle, steady‐state analysis of the voltage gain, and presents the performance matrices of the proposed converter. Furthermore, a comparative analysis is made with conventional and recent literature converters. Finally, a 350‐V, 500‐W, and 20‐kHz experimental prototype has been fabricated to validate the operation and corroborate the theoretical waveforms with experimental results.

Improved ultra voltage gain switched inductor based-Y-Source DC/DC converter with low device stress

ABSTRACT This article proposesanImproved ultra-high voltage gain Switched Inductor-Based Y-Source Converter (SI-YSC) forphotovoltaic (PV) and Fuel Cell (FC) applications. A single switch is employed to generate a high voltage boost at the load, and this topology provides a high voltage conversion ratio, minimal voltage stress on the switch, and continuous input current. The paper comprehensively examines passive components’ steady-state operation, design, and analysis. In addition, in order to comprehend the projected lifespan of the topology in different environments and operating conditions, the converter’s reliability is assessed to determine the mean time to failure of each component. To demonstrate the advantages of the proposed topology, an in-depth comparison is conducted between it and other Y source converters. The circuit design is verified using MATLAB/Simulink and a prototype model for an output power of 100 W. The results of this verification process are then analysed and discussed.

A New Wide Range and High Voltage Conversion Bidirectional DC/DC Converter for DC Microgrid

ABSTRACTBidirectional DC/DC converters (BDCs) are crucial in energy storage integration with DC microgrid. In this article, a new wide‐range and high voltage conversion (VC) nonisolated BDC with simple structure having reasonable components (total 13) is proposed. The proposed BDC with symmetrical VC ratio delivers high conversion of voltage within the vicinity of 0.5 duty ratio in both boost and buck modes of operation. In addition, the proposed BDC has features of continuous currents at low and high voltage stages and reduced switch voltage stress. This article presents the proposed BDC with circuit configuration and its detailed steady‐state boost and buck mode analyses to verify achievable VC ratio and design consideration. With the designed practical model of the proposed BDC, loss analysis is exhibited to verify the conversion efficiency in boost and buck modes of operation. In real time, experimental prototype of the proposed BDC is operated with LAUNCHXL‐F28379D kit to realize switching pulse generation. The experimental response of the entire proposed BDC operation is captured at 200 W loading. The attained experimental results and discussions validate the proposed BDC operation with the mentioned features. Finally, a comparative analysis with existing BDCs is performed to prove the competence of the proposed BDC for DC microgrid.

Analysis of Optimal HVDC Back-to-Back Placement Based on Composite System Reliability

HVDC is a promising interconnection solution for connecting asynchronous systems and ensuring power control. In Indonesia, a remote industrial system in Sumatra is experiencing load growth and has the option to draw power from the Sumatra system. However, due to frequency differences, the use of HVDC is crucial. The Generation Expansion Planning has proposed six converters but not their interconnection points. This study will determine the most reliable interconnection locations. The chosen converters are modular multilevel converters (MMCs) with high modularity. The converter reliability modeling considers voltage levels, the number of modules, and redundancy strategies. This modeling is then implemented at the power system level to obtain the best placement at the available high-voltage (HV) substation options. Determining the best placement is based on the optimal reliability index. The optimal placement also includes the option to convert from HV to medium-voltage (MV) interconnection. MV interconnection offers higher flexibility but tends to be more expensive. The availability for HV converters is 99.69%, while for MV converters, it is slightly higher, at 99.81%. Additionally, converting from HV to MV reduces the SAIFI (system average interruption frequency index) from 0.2668 to 0.2284 occurrences per year, lowering the interruption cost from 7.804 million USD to 5.737 million USD per year. The sensitivity of interruption, investment, and maintenance costs shows that converting at least one HV converter to MV remains economical. In this case study, the optimal converter placement includes Area VI–2, recommended for conversion from HV to a more distributed MV configuration, improving reliability and economic efficiency.

Distance preserving machine learning for uncertainty aware accelerator capacitance predictions

Abstract Accurate uncertainty estimations are essential for producing reliable machine learning models, especially in safety-critical applications such as accelerator systems. Gaussian process models are generally regarded as the gold standard for this task; however, they can struggle with large, high-dimensional datasets. Combining deep neural networks with Gaussian process approximation techniques has shown promising results, but dimensionality reduction through standard deep neural network layers is not guaranteed to maintain the distance information necessary for Gaussian process models. We build on previous work by comparing the use of the singular value decomposition against a spectral-normalized dense layer as a feature extractor for a deep neural Gaussian process approximation model and apply it to a capacitance prediction problem for the High Voltage Converter Modulators in the Oak Ridge Spallation Neutron Source. Our model shows improved distance preservation and predicts in-distribution capacitance values with less than 1% error.

Hardware Testing Methodologies for Wide Bandgap High-Power Converters

Wide bandgap (WBG) power semiconductor devices are increasingly replacing silicon IGBTs in high-power and high-voltage power electronics applications. However, there is a significant gap in the literature regarding efficient testing methodologies for high-power and high-voltage converters under constrained laboratory resources. This paper addresses this gap by presenting comprehensive, hardware-focused testing methodologies for high-power and high-voltage WBG power semiconductor-based converter bring-up before the control validation phase steps in. The proposed methods enable thorough evaluation and validation of converter hardware, including device switching characteristics, driving circuit functionality, thermal management performance, insulation integrity, and sustained operation at full power. We utilized the double pulse test (DPT) to characterize switching performance in a two-level phase leg configuration, extract circuit parasitics, and validate magnetic components. The DPT was further applied to optimize gate driving circuits, validate overcurrent protection mechanisms, and measure device on-resistance. Additionally, a multicycle test was introduced to rapidly assess steady-state converter performance and estimate efficiency. Recognizing the critical role of thermal management in high-power converters, our methodologies extend to the experimental extraction of key thermal parameters—such as junction-to-ambient thermal resistance and thermal capacitance—via a heat loss injection method. A correlation method between temperature sensor measurements and junction temperature is presented to enhance the accuracy of device temperature monitoring during tests. To ensure reliability and safety, dielectric withstand tests and partial discharge measurements were conducted at both component and converter levels under conventional 60 Hz sinusoidal and high-frequency PWM waveforms. Finally, we highlight the importance of testing converters under full voltage, current, and thermal conditions through power circulating tests with minimal power consumption, applicable to both non-isolated and isolated high-power converters. Practical examples are provided to demonstrate the effectiveness and applicability of these hardware testing methodologies.

Байланған мультикоптердің эскиздік моделін зерттеу

The components of the multicopter were analyzed, and its drawing was created in the AutoCAD program, after which an experimental sample was developed. One of the design features of multicopters is the ability to fold them. There are several models that are convenient to fold for transportation and easy to prepare for use. Despite the advantages such as high maneuverability and the ability to hover in place, multicopters also have some disadvantages: limited flight time, low speed and lightness compared to fixed wings. To extend the time in the air, the multicopter can be connected by cable to a power source on the ground. An inverter with a battery in the multicopter component provides autonomy in the event of a cable break, allowing it to be temporarily held in the air. These studies were carried out on the topic of grant financing AR19679602 «Development of a tethered unified dual-purpose multicopter platform with an inverter with increased frequency switching and a high voltage conversion coefficient».

Dual Hydrogen Production System: Synergistic Effect of Ru and Ce Over Cu2O Nanotubes Drives Hydrogen Evolution and Formaldehyde Oxidation.

Water splitting for hydrogen production is limited by high cell voltage and low energy conversion efficiencies due to the slow kinetic process of the oxygen evolution reaction (OER). Here, an electrolytic system is constructed in which the cathode and anode co-release H2 at ultra-low input voltage using formaldehyde oxidation reaction (FOR) instead of OER. The prepared RuCe co-doped Cu2O nanotubes on copper foam (RuCe-Cu2O/CF) are used as electrode materials for the HER-FOR system. A current density of 0.8 A cm-2 is achieved at 0.55V, and a stable hydrogen production process is realized at both the cathode and anode. Density functional theory (DFT) studies show that the synergistic effect of Ru and Ce drives: i) the d-band center of RuCe-Cu2O/CF away from the Fermi energy level; ii) the energy barrier for the C─H cracking of the H2C(OH)O* intermediate in FOR is lowered, which promotes the formation of H2 from H*, and iii) ΔGH* tends to 0 (-0.1eV), optimizing the reaction kinetics of HER. This work provides a new design for an efficient catalyst for dual hydrogen production systems from water splitting.

Optimal Multiple Wind Power Transmission Schemes Based on a Life Cycle Cost Analysis Model

Due to the high cost and complex challenges faced by offshore wind power transmission, economic research into offshore wind power transmission can provide a scientific basis for optimal decision-making on offshore wind power projects. Based on the analysis of the topology structure and characteristics of typical wind power transmission schemes, this paper compares the economic benefits of five different transmission schemes with a 3.6 GW sizeable onshore wind farm as the primary case. Research includes traditional high voltage alternating current (HVAC), voltage source converter high voltage direct current transmission (VSC-HVDC), a fractional frequency transmission system (FFTS), and two hybrid DC (MMC-LCC and DR-MMC) transmission scenarios. The entire life cycle cost analysis model (LCCA) is employed to thoroughly assess the cumulative impact of initial investment costs, operational expenses, and eventual scrap costs on top of the overall transmission scheme’s total cost. This comprehensive evaluation ensures a nuanced understanding of the financial implications across the project’s entire lifespan. In this example, HVAC has an economic advantage over VSC-HVDC in the transmission distance range of 78 km, and the financial range of a FFTS is 78–117 km. DR-MMC is better than the flexible DC delivery scheme in terms of transmission capacity, scalability, and offshore working platform construction costs in the DC delivery scheme. Therefore, the hybrid DC delivery scheme of offshore wind power composed of multi-type converters has excellent application prospects.

Dual input single Output quadratic Boost converter for DC microgrid

DC-DC converters play a critical role in various applications, including DC microgrids, electrical vehicles, data centres and aerospace power systems. This article provides a description of a non-isolated Dual Input Single Output Quadratic Boost DC-DC Converter (DISOQBC) designed for DC microgrids. PV module and battery are low dc voltage power generators. DC microgrid requires high voltage for its operation effectively. By utilizing the proposed converter, the PV module and battery are integrated with separate sources. Achieving a high efficiency and voltage conversion ratio, the proposed converter is distinguished by low components used. The operation of the converter, component design, steady state analysis, and small-signal model has been reported. The proposed converter's benefits include the converter's ability to handle more than one source, deliver more gain than the conventional converter, simple control and reduced losses. The outcome of simulating the converter validates the proposed converter's theoretical operation. The laboratory prototype is ultimately employed to validate and verify the performance of the proposed DISOQBC.

Research on continuous commutation failure suppression strategy for multi-feed DC transmission system considering harmonic characteristic factors

Abstract Regarding the sustained issues of commutation failures in the hybrid double-fed DC system encompassing Line Commutated Converter High Voltage Direct Current (LCC-HVDC) and Modular Multilevel Converter High Voltage Direct Current (MMC-HVDC, from the perspective of harmonics, the harmonics in the voltage waveform of the AC bus on the inverter side are analyzed. Besides, a commutation failure suppression strategy for the hybrid doubly-fed DC transmission system based on the minimum shutdown area is designed, in which the setting value of the shutdown angle of the harmonic is considered in the minimum shutdown area. The reactive power is obtained by attaching the setting value to the reactive power control link of MMC-HVDC, and the simulation analysis in PSCAD verifies that the strategy can make the MMC-HVDC output more reactive power during the fault in the weak AC system. Increasing the shut-off margin of the manifold reduces the potential for continuous commutation failures in LCC-HVDC.

Enhanced Control of Polymer Electrolyte Membrane Fuel Cell Fed Basic Series Positive Super Voltage Lift Luo Converter Using Interval Type-2 Fuzzy Logic

An eco-friendly and renewable energy source, Polymer Electrolyte Membrane (PEM) fuel cells offer various advantages such as stability and efficiency. The present study aims to control output voltage of PEM fed basic series positive super voltage lift luo (PSVLL) converter. The model, which consists of a fuel cell and a basic series PSVLL converter, was designed in Matlab/Simulink simulation environment. The control of the PSVLL converter output voltage was performed using an interval type-2 takagi-sugeno-kang fuzzy logic (IT2TSKFL) and type-1 takagi-sugeno-kang fuzzy logic (T1TSKFL) controllers comparatively. The simulation study results demonstrated that the PEM fuel cell fed basic series PSVLL converter reached optimal current and voltage values with IT2TSKFL under nominal and different operating conditions. Moreover, IT2TSKFL improved average settling time of control system by 22.335% compared to T1TSKFL controller.

Extended high gain DC‐DC converter with switched‐inductors, switched‐capacitors and soft‐switching: Analysis and implementation

AbstractThis paper proposes an extended DC‐DC converter with high voltage conversion ratio and soft‐switching ability. The proposed converter has active switched‐inductors, switched‐capacitors included in the conventional high gain converter and operates in continuous conduction mode (CCM). Simple auxiliary resonant elements are added on the primary leg of the converter to provide design freedom for soft‐switching operation. The significant merits of the proposed converter are lesser voltage and current stresses, high voltage gain with reduced component count and better efficiency. Additional feature of this converter is soft‐switching operation under different load conditions and duty ratios without considerably increasing stresses. The zero voltage switching (ZVS) turn‐on operation is obtained for all switching devices. Therefore, switching power losses are minimized greatly. This paper presents the description, principles of operation and steady state analysis in comparison with the existing high gain converters. The theoretical analysis is verified with a 350 W prototype operated at input is 20 V and output is 220 V. The overall efficiency achieved is 96.7%. The obtained results confirm ZVZCS operation at full load.

Preliminary Verification of the PHITS Code Applicability to Conversion Efficiency Calculation of Direct Charge Nuclear Battery

A direct charge nuclear battery, or DCNB, is one of the nuclear batteries based on direct energy conversion and is characterized by exceptional high voltage generation and conversion efficiency higher than other nuclear batteries. For studying potential applications of DCNB, a preliminary estimation of DCNB electrical power and performance is required; hence, conversion efficiency analysis is crucial. For preliminary verification purposes, an ideal DCNB conversion efficiency was calculated under the simplified electron transport model by using the general-purpose Monte Carlo particle transport calculation code PHITS. The result was compared with a reference experimental efficiency for a T-loaded parallel plate DCNB, and the resulting relative error was approximately 12%. Considering the relative error of 20% or less in DCNB conversion efficiency shown by preceding studies, the resulting error was comparable, and it was concluded that the PHITS code is sufficiently applicable to DCNB conversion efficiency analysis.

A High Step-Down SiC-Based T-Type LLC Resonant Converter for Spacecraft Power Processing Unit

A spacecraft power processing unit (PPU) is utilized to convert power from solar arrays or electric batteries to the payload, including electric propulsion, communication equipment, and scientific instruments. Currently, a high-voltage converter is widely applied to the spacecraft PPU to improve power density and save launch weight. However, the high voltage level poses challenges such as high step-down ratios and high power losses. To achieve less conduction loss, a SiC-based T-type three-level (TL) LLC resonant converter is proposed. To further broaden the gain range and achieve high step-down ratios, a variable frequency and adjustable phase-shift (VFAPS) modulation scheme is proposed. Meanwhile, the steady-state time-domain model is established to elaborate the operation principles and boundary conditions for soft switching. Furthermore, the optimal resonant element design considerations have been elaborated to achieve wider gain range and facilitate easier soft switching. Furthermore, the numerical solutions for switching frequency and phase shift (PS) angle under each specific input could be figured out. Finally, the effectiveness of this theoretical analysis is demonstrated via a 500-W experimental prototype with 650∼950-V input and constant output of 48-V/11-A.

Analysis of A Bidirectional Resonant Converter Applied in High/Low Voltage Conversion

In order to ensure the safe and reliable operation of the ship, the emergency power supply of the ship can provide short-term power supply when the main power supply of the ship fails. This paper proposes a two-way LLC resonant converter to be used in marine emergency power supplies. While ensuring the high efficiency and soft switching performance of the converter, it realizes high and low voltage conversion and bidirectional energy flow. By analyzing the topology, working principle and gain under variable frequency control of the two-way LLC resonant converter, and constructing the principle prototype and verifying its performance, the experiment shows that the application of the two-way LLC resonant converter in the emergency power supply can achieve high and low voltage The conversion and has good soft switching characteristics.

A high step‐up high step‐down coupled inductor based bidirectional DC–DC converter with low voltage stress on switches

AbstractThis paper proposes, a novel soft‐switching bidirectional direct current to direct current (DC–DC) converter based on switched‐capacitor and coupled‐inductor. The proposed converter has a simple structure and utilizes four switches and a three‐winding coupled inductor and can achieve a high voltage conversion ratio in both step‐up/step‐down operations. By employing the switched‐capacitor technique, voltage stress across the power switches is low and therefore low voltage rating switches can be adopted to reduce the losses of their conduction. Soft‐switching characteristic of the proposed converter reduces the switching loss of active power switches and raises the conversion efficiency. This paper presents theoretical analysis for all operating modes of the converter, voltage conversion ratio, voltage and current stresses of all power switches. Finally, to test the validity of theoretical results and demonstrate the performance of the converter, experimental results are provided.

Transient response mitigation using type-2 fuzzy controller optimized by grey wolf optimizer in converter high voltage direct current

Long high voltage direct current (HVDC) transmission link is commonly used to transmit electrical energy via land or under-sea cable. The long HVDC avoids reactive power losses (RPL) and power stability problems (PSP). On the contrary, the RPL and PSP phenomena occur in long high voltage alternative current-link (HVAC) caused by the high reactive component in the HVAC-link. However, the HVDC produces a high and slow transient current response (TCR) on the high value of the up-ramp rate. Interval type-2 fuzzy (IT2F) control on converter-side HVDC is proposed to mitigate this TCR problem. The IT2F is optimized by grey wolf optimizer (GWO) to adjust input-output IT2F parameters optimally. The performance of IT2F-GWO is assessed by the minimum value of integral time squared error (ITSE), peak overshoot, and settling time of the TCR. The IT2FC-GWO performance is validated by the performance of IT2F control that is optimized by genetic algorithm (IT2F-GA) and proportional integral (PI) controller. Simulation results show that the IT2F-GWO performs better with small ITSE, low peak overshoot, and shorter settling times than competing controllers.

A Novel Hybrid MPPT Controller for PEMFC Fed High Step-Up Single Switch DC-DC Converter

At present, there are different types of Renewable Energy Resources (RESs) available in nature which are wind, tidal, fuel cell, and solar. The wind, tidal, and solar power systems give discontinuous power supply which is not suitable for the present automotive systems. Here, the Proton Exchange Membrane Fuel Stack (PEMFS) is used for supplying the power to the electrical vehicle systems. The features of fuel stack networks are very quick static response, plus low atmospheric pollution. Also, this type of power supply system consists of high flexibility and more reliability. However, the fuel stack drawback is a nonlinear power supply nature. As a result, the functioning point of the fuel stack varies from one position to another position on the V-I curve of the fuel stack. Here, the first objective of the work is the development of the Grey Wolf Optimization Technique (GWOT) involving a Fuzzy Logic Controller (FLC) for finding the Maximum Power Point (MPP) of the fuel stack. This hybrid GWOT-FLC controller stabilizes the source power under various operating temperature conditions of the fuel stack. However, the fuel stack supplies very little output voltage which is improved by introducing the Single Switch Universal Supply Voltage Boost Converter (SSUSVBC) in the second objective. The features of this proposed DC-DC converter are fewer voltage distortions of the fuel stack output voltage, high voltage conversion ratio, and low-level voltage stress on switches. The fuel stack integrated SSUSVBC is analyzed by selecting the MATLAB/Simulink window. Also, the proposed DC-DC converter is tested by utilizing the programmable DC source.