DC Converter Research Articles

Size, Efficiency, Reliability, and Cost Analysis of a Multiport Traction Inverter With Downsized DC–DC Converter for a Catenary/Battery Tram

Size, Efficiency, Reliability, and Cost Analysis of a Multiport Traction Inverter With Downsized DC–DC Converter for a Catenary/Battery Tram

A High Step-Up Hybrid Y-Source-Quasi-Z Source DC–DC Converter for Renewable Energy Applications

A High Step-Up Hybrid Y-Source-Quasi-Z Source DC–DC Converter for Renewable Energy Applications

A Current-Fed Transformer-Based High-Gain DC–DC Converter With Inverse Gain Characteristic for Renewable Energy Applications

A Current-Fed Transformer-Based High-Gain DC–DC Converter With Inverse Gain Characteristic for Renewable Energy Applications

Integration of DC–DC Converters for OBC, LDC, and TC in Electric Vehicles

Integration of DC–DC Converters for OBC, LDC, and TC in Electric Vehicles

Frequency-Modulated High-Gain Boost–Flyback DC–DC Converter for Renewable Energy Systems

Frequency-Modulated High-Gain Boost–Flyback DC–DC Converter for Renewable Energy Systems

Self-powered sensors utilizing single-pillar thermocells with pyrolytic graphite sheet electrodes: harvesting body heat and solar thermal energy

This study investigates the development of self-powered sensors employing single-pillar thermocells to harness body heat and solar thermal energy. A pyrolytic graphite sheet was selected for its low water vapor permeability, and its surface was modified to be hydrophilic to minimize interfacial resistance. Two types of DC–DC converters, Asahi Kasei Microdevices AP4473 and matrix mercury, underwent evaluation for compatibility with these thermocells. The compact 1.5 cm3 (1 cm × 1 cm × 1.5 cm) device effectively powered the AP4473 converter, illuminating a light-emitting diode. A larger device (2.5 cm × 2.5 cm × 1.5 cm) efficiently drove the matrix mercury converter, enabling the operation of bluetooth low-power sensors. These self-powered sensors wirelessly provided humidity and temperature data using solar thermal energy for approximately 4 h per day during peak temperature differences in January. This study showcases the potential of thermocells for sustainable energy harvesting and suggests avenues for future research, such as exploring alternative heat sources like geothermal energy to power these sensors.

Towards maximum efficiency of an open-cathode PEM fuel cell system: A comparative experimental demonstration

Despite its high energy density and zero-carbon emissions, the path to large commercialization for Proton Exchange Membrane Fuel Cell (PEMFC) systems faces challenges related to cost reduction, efficiency enhancement, and durability improvement. One key strategy to address these hurdles is the development of reliable control algorithms that ensure operation at the Maximum Efficiency Point (MEP) of PEMFC systems. This optimization is essential for achieving high efficiency, a crucial factor for PEMFC technology commercial viability. This work explores the experimental design, implementation, and evaluation of Maximum Efficiency Point Tracking (MEPT) control algorithms for a PEMFC system. The investigated methods span across five distinct categories: conventional, data-driven, metaheuristics, online model identification, and filter-based approaches. To assess these methods, a real-time small-scale PEMFC system test bench was built. The setup consists of 200 W open-cathode PEMFC, industrial step-up DC–DC converter, programmable load and a cost-effective measurement and monitoring unit. Merits and demerits of each method are then discussed based on different performance metrics such as tracking speed, hydrogen consumption and power stress. Comparative analysis of the results reveals that, while all the algorithms achieved a maximum electrical efficiency of about 48%, data-driven methods exhibited a superior trade-off between performance metrics. This ultimately leads to improved PEMFC durability.

Reflux Power Optimization of a Dual-Active Hybrid Full-Bridge Converter Based on Active Disturbance Rejection Control

The dual-active hybrid full-bridge (H-FDAB) DC–DC converter has great potential in medium-voltage high-power photovoltaic power station applications by introducing a three-level bridge arm to increase the output voltage range. However, its mathematical model and optimum modulation schemes have not been fully explored. Under the traditional PI control, the H-FDAB DC–DC converter will produce significant reflux power, which will lead to a decrease in converter efficiency and output voltage fluctuation. On this basis, this paper proposes a reflux power optimization strategy for an H-FDAB DC-DC converter based on active disturbance rejection control (ADRC). Firstly, the structure and power characteristics of the H-FDAB DC–DC converter are analyzed, and the relationship among the reflux power, the transmission power, and the phase shift angle is derived. Secondly, to reduce the complexity of the control calculation, upon the foundation of dual phase-shifting modulation, the Karush–Kuhn–Tucker (KKT) condition is used to solve for the phase shift angle that corresponds to the minimum reflux power. Simultaneously, we develop an ADRC loop utilizing an extended state observer (ESO) for the real-time estimation of system states. We also consider the sudden changes in input voltage, load switching, and transmission power fluctuations caused by reflux power optimization strategies as system disturbances and compensate for them accordingly. Finally, the experiments conclusively validate the designed control strategy’s correctness and feasibility.

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.

A Dual Constant Current Output Ports WPT System Based on Integrated Coil Decoupling: Analysis, Design, and Verification

With the high integration of power electronic devices, wireless power transfer (WPT) systems are required to have output characteristics of different specifications that are independent of the load. However, existing methods for realizing dual-output WPT systems have problems such as complex circuits, cumbersome control schemes, low system stability, insufficient system space utilization, and unnecessary cross-coupling. Therefore, in order to solve the above problems, this paper proposes a dual-receiver WPT system with dual constant current (CC) output based on an integrated decoupling coil. In this system, the DD coil is wound vertically in series with the solenoid coil and serves as the first receiving coil to achieve energy transmission in the system. While the solenoid coil is used in the transmitting coil and the second receiving coil, and the coils are perpendicular to each other to achieve natural decoupling. Furthermore, the receiving coils are integrated together on the receiving side ferrite plate. Therefore, there is no cross-coupling interference in the system, which simplifies the system design. Firstly, the natural decoupling characteristics of the magnetic coupler and the coil optimization method are analyzed in detail theoretically. Secondly, a detailed mathematical analysis is performed on the dual CC output characteristics with different specifications that are load-independent and have zero phase angle operation. Again, the zero voltage switching of the inverter can be achieved by changing the compensation component parameters through simulation verification. Finally, a prototype with a rated power of 283 W is constructed for validation purposes. The first receiver delivers a CC output of 3 A, while the second receiver provides a CC output of 4 A, with the DC–DC conversion efficiency reaching a peak of 90.2%. The experimental results confirm the accuracy of the theoretical analysis.

Modeling and stability analysis of enhanced gain active switched inductor impedance source non-isolated DC to DC converter for PV applications

Modeling and stability analysis of enhanced gain active switched inductor impedance source non-isolated DC to DC converter for PV applications

Mathematical modeling and stress‐aware stability analysis of a nonideal multiport Single Inductor DC–DC converter for renewable energy

Mathematical modeling and stress‐aware stability analysis of a nonideal multiport Single Inductor DC–DC converter for renewable energy

Enabling High-Power Conditioning and High-Voltage Bus Integration Using Series-Connected DC Transformers in Spacecrafts

This article proposes a photovoltaic power processor for high-voltage and high-power distribution bus, between 300 V and 900 V, to be used in future space platforms like large space stations or lunar bases. Solar arrays with voltages higher than 100 V are not available for space application, being necessary to apply power conversion techniques. The idea behind this is to use series-connected zero-voltage and zero-current unregulated and isolated DC converters to achieve high bus voltage from the existing solar arrays. Bus regulation is then achieved through low-frequency hysteretic control. Topology description, semiconductor selection, design procedure, simulation and experimental validation, including tests in vacuum and partial pressures, are presented.

Transformer-less high gain DC–DC converter design and analysis for fuel cell vehicles

High-power converters with significant gains represent established configurations that hold appeal for applications in the industrial and commercial sectors, such as fuel cell electric vehicles (FCEV), energy backup systems, and automotive headlamps. Existing literature predominantly features topologies employing a single-duty ratio. However, this singular approach may not be dependable for operations with high-duty cycles, necessitating the incorporation of additional components to enhance voltage gain. To address this, the current study introduces the concept of time-sharing within the context of a high-gain non-isolated DC–DC converter. This innovative approach achieves substantially higher output voltage gains, approximately 13.33 times that of the input voltage. The analysis of the proposed converter is approached from various perspectives. Finally, it is examined within the MATLAB/Simulink environment, where the theoretical analysis is validated, and an efficiency of 97.4% is achieved.

A comprehensive analysis and closed-loop control of a non-isolated boost three-port converter for stand-alone PV system

This study critically investigates analysis and control of non-isolated boost three-port DC to DC converter (TPC) forstandalone PV system. The converter is controlled such that regulates flow of power from PV array to load and batteries as storage devices.According to PV power, there are four operating modes of operation of converter. Simple reduced-order dynamic models of the converter in various modes of operation are obtained using state-space averaging and small-signal techniques. In this work, the controllers of the closed-loop scheme are designed and only two controllers are used to achieve output voltage regulation, and to extract maximum power from PV array under different operating conditions. Closed-loop system simulation is studied to verify the operation of converter with the designed controllers in different modes. Transition between modes is presented with solar radiation variation and change of connected loads. Experimental verification of control systems at different modes of operation is investigated. The experimental results show that the controllers can regulate the power flow between TPC three ports and regulate output voltage under PV irradiance variation and load changing. The controller shows good performance measures such as maximum settling time of 0.06 s, maximum steady-state ripples of ±0.8 %, and 99.3 % power efficiency.

A novel development of wide voltage supply DC–DC converter for fuel stack application with PSO-ANFIS MPPT controller

The present power production companies are working on renewable energy systems because their features are more reliable for the local energy consumers, high continuity in the energy production, and less cost is required for maitainence. In this article, the proton exchange membrane fuel stack (PEMFS) renewable energy is utilized to supply energy to the automotive systems. Here, the PEMFS is selected because of its merits are high energy density, quick system response concerning the source operational temperature, and more suitable for electric vehicle application. However, the PEMFS supplied voltage is completely nonlinear which is solved by utilizing the modified particle swarm optimization with adaptive neuro-fuzzy inference system (MPSO with ANFIS) controller. This hybridization-based maximum power point tracking controller provides more accuracy, high power point identifying speed, best dynamic response at different fuel stack functioning temperature conditions, and easy maitainence. Here, the fuel stack generated current is very high which is optimized by introducing the new DC–DC converter. The advantages of this DC–DC converter are more voltage transformation ratio, low-level voltage stress appearing across the switches, and wide voltage gain. The overall system is investigated by utilizing the MATLAB/Simulink tool.

A novel active cell balancing topology for serially connected Li-ion cells in the battery pack for electric vehicle applications

In a Battery Management System (BMS), cell balancing plays an essential role in mitigating inconsistencies of state of charge (SoCs) in lithium-ion (Li-ion) cells in a battery stack. If the cells are not properly balanced, the weakest Li-ion cell will always be the one limiting the usable capacity of battery pack. Different cell balancing strategies have been proposed to balance the non-uniform SoC of cells in serially connected string. However, balancing efficiency and slow SoC convergence remain key issues in cell balancing methods. Aiming to alleviate these challenges, in this paper, a hybrid duty cycle balancing (H-DCB) technique is proposed, which combines the duty cycle balancing (DCB) and cell-to-pack (CTP) balancing methods. The integration of an H-bridge circuit is introduced to bypass the selected cells and enhance the controlling as well as monitoring of individual cell. Subsequently, a DC–DC converter is utilized to perform CTP balancing in the H-DCB topology, efficiently transferring energy from the selected cell to/from the battery pack, resulting in a reduction in balancing time. To verify the effectiveness of the proposed method, the battery pack of 96 series-connected cells evenly distributed in ten modules is designed in MATLAB/Simulink software for both charging and discharging operation, and the results show that the proposed H-DCB method has a faster equalization speed 6.0 h as compared to the conventional DCB method 9.2 h during charging phase. Additionally, a pack of four Li-ion cells connected in series is used in the experiment setup for the validation of the proposed H-DCB method during discharging operation. The results of the hardware experiment indicate that the SoC convergence is achieved at ~ 400 s.

Making of an Indigenous and Efficient Powertrains for EV, HEV & FCEV’s

Rise in greenhouse gas emissions which is resulting into ozone layer depletion and global warming effect is alarming to control CO2 emissions by drastically reducing fossil fuel consumption from the vehicles. This need has already started trend towards extreme downsizing and down speeding of Internal Combustion Engines (ICE) for making them highly efficient. In addition to this use of after treatment devices viz. Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Lean NOx Catalyst (LNT), Selective Catalytic Reduction (SCR) are helping to a great extent for meeting emission norms till Euro - VI for automotive sector, Tier–IV F and Stage V for Off Highway Power sector. However, to address present greenhouse effect along with exponential decay of fossil fuels, there is need to achieve CO2 emissions less than 100 g/km or to achieve practically zero carbon footprint using an alternate powertrain. Electrification is one of the promising solutions and which is three-fold in present situation. The first level of electrification comes in the form of Hybrid Electric Vehicle (HEV) technology followed by Battery Electric Vehicles and Fuel Cell Electric Vehicles as second and third level of electrification respectively. In all these technologies a common thread is running in the form of an efficient electric drive train. Several efforts have been taken to improve torque per unit ampere by use of efficient motor and motor control algorithms viz PMSM powered with FOC, by developing controls which take care of parametric variations and external force disturbances by use of back stepping techniques which are based on rotor resistance estimation by fuzzy logic, FOC techniques based on adaptive input-output feedback linearization, by shifting towards high voltage systems, by going for higher switching frequencies for inverters which uses silicon carbide based MOSFET switches, by exploring use of multilevel inverters for Total Harmonic Distortion (THD) control etc. Use of E Axle based powertrains in EV, HEV and FCEV offers additional complimentary benefits apart from technology options described above. E Axle based powertrains offers flexibility in generating three variants of vehicle using one electric drive train architecture viz. making EV, HEV & FCEV. Compactness, modularity, scalability, flexibility along with efficient cooling system management and control over active current losses due to use of bus bars are the implicit advantages of E Axle based powertrains. These advantages further get multiplies if we go for 3 in 1 (gearbox + Stator housing + Inverter) architectures which are predominantly used in independent suspension-based vehicles. Lot of efforts are going on to inherit this technology for rigid axle suspension based commercial vehicles. Research in this area is getting further extended to make 5 in 1 E Axles where there will addition of DC - DC converter and On-Board Charger (OBC) apart from components present in 3 in 1 configuration. Two major challenges need to be addressed and to be resolved while designing E Axle based powertrains by doing concurrent vehicle engineering. This is mainly due to increased unsprang weight that need to be handled by suspension system and exposed electric drive components to excitation loads coming from roads. Fig: Indigenously Developed E Axle Based Powertrain for Small Commercial VehiclesBy proper lay outing for effective vehicle mass distribution and required CG location which is essential from overall vehicle dynamics, more space can be offered by E Axle based powertrains for increasing battery energy density for getting more electric range in case of BEV’s. This add on space benefit extend help in packaging of hydrogen fuel cell integrated with power cells in case of FCEV’s. Thus, E Axle based powertrains proves to be modern and most efficient way of making EV, HEV & FCEV’s.

A high-efficiency poly-input boost DC–DC converter for energy storage and electric vehicle applications

This research paper introduces an avant-garde poly-input DC–DC converter (PIDC) meticulously engineered for cutting-edge energy storage and electric vehicle (EV) applications. The pioneering converter synergizes two primary power sources—solar energy and fuel cells—with an auxiliary backup source, an energy storage device battery (ESDB). The PIDC showcases a remarkable enhancement in conversion efficiency, achieving up to 96% compared to the conventional 85–90% efficiency of traditional converters. This substantial improvement is attained through an advanced control strategy, rigorously validated via MATLAB/Simulink simulations and real-time experimentation on a 100 W test bench model. Simulation results reveal that the PIDC sustains stable operation and superior efficiency across diverse load conditions, with a peak efficiency of 96% when the ESDB is disengaged and an efficiency spectrum of 91–95% during battery charging and discharging phases. Additionally, the integration of solar power curtails dependence on fuel cells by up to 40%, thereby augmenting overall system efficiency and sustainability. The PIDC’s adaptability and enhanced performance render it highly suitable for a wide array of applications, including poly-input DC–DC conversion, energy storage management, and EV power systems. This innovative paradigm in power conversion and management is poised to significantly elevate the efficiency and reliability of energy storage and utilization in contemporary electric vehicles and renewable energy infrastructures.

Simulation of fire combustion process in valve hall of DC converter power station

To investigate the fire danger of the valve hall, a 3D numerical model of the DC converter substation's valve hall is created by using the fire dynamics simulator (FDS) program and the fire burning process of the valve hall is simulated. In particular, the procedure of simulating the fire burning in the valve hall under various fire source positions is accomplished by varying certain parameters. The smoke spreading process, ambient temperature field, and heat release rate curve under various fire source placements are compared based on the results of the simulation calculations. The findings demonstrate that under various fire source locations, the valve hall's combustion process varies as well. This study compares the time for smoke to fill the entire valve hall, the maximum temperature within the valve hall, and the maximum fire source heat release efficiency in different fire scenes. The results indicate that in fire scenes where the fire source is closer to the middle position, the time for smoke to spread throughout the valve hall is shorter, and the fire source heat release rate is higher. Conversely, in fire scenes where the fire source is closer to the edge, the maximum temperature within the valve hall is higher. The numerical simulation of the valve hall in this DC converter station assessed the hazards under different fire scenes, aiming to maximize the safety of the valve hall. It provides reliable guidance for maximizing the safety of the valve hall and facilitating firefighting and rescue efforts, thus protecting personal safety and minimizing property damage.