As modern power systems evolve towards greater performance, reliability, and energy efficiency, there is a growing need for advanced control strategies capable of handling complex converter dynamics and external disturbances. This paper addresses the voltage regulation challenge in isolated high-gain DC–DC power converters by proposing a topology that integrates an isolated boost converter with a voltage doubler. This combined structure enables high voltage conversion ratios while providing galvanic isolation, making it particularly suitable for applications such as electric vehicles, renewable energy systems, and industrial DC distribution networks. To achieve precise voltage regulation and improve dynamic performance, we develop and evaluate two robust nonlinear control strategies: an Adaptive Barrier Super-Twisting Sliding Mode Controller (AB-STSMC) and a Synergetic Super-Twisting Sliding Mode Controller (S-STSMC). These controllers are designed to mitigate the effects of parameter uncertainties, input disturbances, and nonlinear load behavior, while ensuring finite-time convergence and chattering-free operation. A comprehensive nonlinear model of the converter is established, and controller stability is rigorously analyzed using Lyapunov-based methods. The proposed controllers are validated through extensive simulations, which demonstrate their superior performance under various operating conditions, including step-load variations, input voltage fluctuations, and component drift. In addition to simulation results, Hardware-in-the-Loop (HIL) experiments are conducted using the Delfino LaunchPad F28379D to confirm the practical applicability of the proposed controllers. The HIL setup allows for real-time testing, providing critical insights into the controllers’ performance in a practical hardware environment. The results from these experiments validate that the proposed AB-STSMC and S-STSMC controllers outperform conventional PID and classical SMC methods, exhibiting faster settling times, improved steady-state accuracy, and enhanced robustness. This work underscores the viability of the proposed control strategies for high-performance, disturbance-resilient DC power conversion in next-generation energy systems. • Proposed AB-STSMC and S-STSMC ensuring finite-time convergence and chattering-free operation. • Achieved precise voltage regulation and superior dynamic response. • Mitigated parameter uncertainties, disturbances, and nonlinear load effects. • Validated performance through nonlinear modeling, Lyapunov stability, simulations and HIL experimentation. • Outperformed PID and classical SMC with faster settling, higher accuracy, and robustness.

Talkative Power Conversion (TPC), also known as switching-ripple communication (SRC), provides cost-effective data transmission for smart grids, DC microgrids, and automotive power systems, but it remains vulnerable to unauthorized access and data interception. This paper proposes an integrated TPC system embedding Advanced Encryption Standard 128 (AES-128) encryption directly into a binary frequency shift keying (FSK)-modulated DC-DC buck converter, eliminating external modems and security hardware. The key novelty is a converter-centric physical-layer co-design that seals plaintext within the converter controller and transmits only ciphertext ripple on the shared DC bus without external modem/security interfaces. Utilizing the converter's intrinsic switching ripple for data transmission, the buck converter transmits encrypted data using 61 kHz and 73 kHz switching frequencies, with a 24 kHz synchronization tone. Real-time encryption, modulation, demodulation, and decryption are implemented on a PYNQ-Z2 FPGA board. Experimental validation demonstrates secure, error-free data transmission with desired power quality, confirming the proposed method's practicality. The integrated FPGA-based solution significantly reduces system complexity and cost, ensuring robust protection against cyber threats in DC power distribution systems.

To systematically compare the effects of different introduction methods on the direct-current (DC) electrical performance of polyethylene insulation, low-density polyethylene (LDPE) modified with an identical content of trans,trans-dibenzalacetone (TTD) was prepared via blending and grafting approaches. The DC breakdown strength, electrical conductivity, space charge behavior, surface potential decay, and trap distribution characteristics of the modified LDPE were comparatively investigated. The results indicate that both blending and grafting modification can effectively regulate the DC electrical behavior of LDPE and improve its insulation performance to varying extents. Compared with the blended system, the grafted samples exhibit a significantly higher DC breakdown strength, increasing from 353.20 kV/mm to 403.31 kV/mm, accompanied by a pronounced reduction in electrical conductivity and a markedly lower average volume charge density under a DC electric field of 40 kV/mm, indicating more effective suppression of space charge accumulation. Meanwhile, a slower surface potential decay process is observed in the grafted samples, revealing pronounced differences in charge trapping characteristics within the materials. Combined with quantum chemical calculations and trap formation analysis, it is suggested that the different introduction methods alter the existence state of functional molecules in the polymer matrix, thereby affecting the stability and effectiveness of charge trap structures. Chemical grafting is favorable for stably transforming the electron-capturing capability of TTD into intrinsic charge trapping structures within LDPE, enabling sustained and effective regulation of charge transport under DC electric fields. This study provides useful insights into the molecular design and optimization of polyethylene-based insulation materials for high voltage DC applications.

Resilient extreme-temperature electronics are critical for applications ranging from quantum computing to space exploration. Ultrawide-bandgap (UWBG) β-Ga2O3 semiconductors are promising for operation across cryogenic and high-temperature regimes; however, their cryogenic performance remains insufficiently explored. Here, we demonstrate β-Ga2O3 transistor operation down to 2 K by exploiting Mott's variable-range hopping (VRH) conduction in impurity bands. The β-Ga2O3 FinFETs exhibit enhancement-mode behavior with a threshold voltage of 1.87 V, an ON/OFF current ratio exceeding 106, and a subthreshold swing of 152 mV/dec at 2 K. Furthermore, a monolithic β-Ga2O3 inverter integrated circuit is realized, achieving a voltage swing of 4.88 V and a voltage gain of 28 at a 5 V supply with DC power dissipation of 0.13 μW at 2 K. Stable cryogenic performance arises from FinFET architecture and precise doping that enable VRH, consistent with a two-band transport model of the β-Ga2O3 channel, hence establishing β-Ga2O3 cryogenic electronics.

Abstract Spin-transfer torque magnetic random-access memory (STT-MRAM) relies on nanoscale magnetic tunnel junctions (MTJs) as its fundamental building blocks. Next-generation STT-MRAM requires strategies that simultaneously improve switching energy efficiency and device endurance. Here, we present the first study of perpendicular STT-MRAM writing assisted by radio-frequency (RF) spin torque. We show that applying a small-amplitude RF pulse prior to a direct-current (DC) write pulse enhances the MTJ switching probability, with the efficiency gain increasing at lower RF frequencies. This RF+DC writing scheme enables shorter DC pulses, thereby improving device endurance. Analytical and numerical modeling qualitatively reproduces the experimental trends, while quantitative discrepancies indicate that realistic MTJ properties beyond idealized models play an important role in RF-assisted switching.

Physics learning in schools often remains dominated by conventional methods, resulting in low student motivation and suboptimal cognitive learning outcomes, particularly when abstract concepts are taught without adequate support for practicum. This condition becomes more challenging in schools with limited laboratory facilities. This study aimed to examine the implementation of discovery-learning-based student worksheets assisted by PhET Interactive Simulations and to determine their effects on students’ learning motivation and cognitive learning outcomes in physics, particularly in the direct current electricity material. This study employed a quasi-experimental method with a pretest-posttest nonequivalent control group design. The research was conducted at Muhammadiyah Senior High School Jayapura and involved 41 students selected through purposive sampling. The instruments used were a learning motivation questionnaire and pretest-posttest items measuring cognitive learning outcomes. The data were analyzed using descriptive statistics, N-gain, independent-samples t-test, and MANOVA using SPSS 16.0. The results showed that students who learned with discovery-learning-based student worksheets assisted by PhET interactive simulations had higher motivation and better cognitive learning outcomes than those who learned with textbook-based worksheets. The independent-samples t-test showed a significance value of 0.000 < 0.05, indicating a significant difference in learning motivation between the two groups. In addition, the MANOVA yielded a p-value of 0.000 < 0.005, indicating a significant difference in both motivation and cognitive learning outcomes. The novelty of this study lies in the integrated use of discovery-learning-based student worksheets and PhET interactive simulations to simultaneously enhance student motivation and cognitive achievement in physics. In conclusion, this approach is effective in fostering active, interactive, and meaningful learning while also serving as an alternative for schools with limited laboratory resources. This study contributes to physics education by providing empirical evidence that integrating structured worksheets, discovery learning, and virtual simulations can enhance both the quality of instruction and student learning performance.

Sinusoidal voltage pulsed electrolysis induced anthocyanins discoloration: an improved method for colorful food 3D printing.

DC Optimal Power Flow (DC-OPF) problems optimize the generators' active power setpoints while satisfying constraints based on the DC power flow linearization. The computational tractability advantages of DC-OPF problems come at the expense of inaccuracies relative to AC Optimal Power Flow (AC-OPF) problems that accurately model the nonlinear steady-state behavior of power grids. This paper proposes an algorithm that significantly improves the accuracy of the generators' active power setpoints from DC-OPF problems with respect to the corresponding AC-OPF problems over a specified range of operating conditions. Using sensitivity information in a machine learning-inspired methodology, this algorithm tunes coefficient and bias parameters in the DC power flow approximation to improve the accuracy of the resulting DC-OPF solutions. Employing the Truncated Newton Conjugate-Gradient (TNC) method, a Quasi-Newton optimization technique, this parameter tuning occurs during an offline training phase, with the resulting parameters then used in online computations. Numerical results underscore the algorithm's efficacy with accuracy improvements in squared two-norm and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\infty$</tex-math></inline-formula>-norm losses of up to 90% and 79%, respectively, relative to traditional DC-OPF formulations.

Same-hardware, stack-scale evidence for PtX syngas routes is scarce. We quantify, on identical solid-oxide hardware, how operating conditions affect stack voltage and specific electricity demand to guide selection between steam electrolysis, paired downstream with RWGS, and direct co-electrolysis. We report new stack-level steam-electrolysis data and benchmark them against our previously published co-electrolysis dataset on the same five-cell electrolyte-supported stack and test rig. Measurements are non-overlapping with aligned operating windows and a single analysis pipeline. A structured design-of-experiments with regression yields sensitivities to current density, fuel-side composition/flow, and temperature. Electrochemical impedance spectroscopy (EIS), distribution of relaxation times (DRT), and in-plane temperature mapping provide mechanistic context for ohmic, charge-transfer, and transport contributions. Within the tested window, co-electrolysis shows stronger voltage sensitivity to current density and the air-outlet setpoint. Differences in specific electricity demand are modest per stack yet material at plant scale. Holding hardware and analysis constant, we deliver a reproducible benchmark that supports route selection and informs thermal and current-density control in commercial PtX plants. • DoE-based quantification of parameter effects on stack voltage (steam EC). • EIS, DRT, and in-plane temperature diagnostics on a 5-cell commercial stack. • Same-hardware benchmark: co-electrolysis shows larger per-unit sensitivities. • At matched production, co-electrolysis requires 2 % higher DC power and kWh Nm − 3 .

Issues of stability and control in power electronics-based energy storage systems: Critical review and methodological extensions of large-scale AC and DC power networks

The rapid growth of electric vehicles (EVs) has increased the demand for efficient and high-power quality battery charging systems. Conventional EV chargers typically use diode bridge rectifiers followed by DC–DC converters for AC–DC power conversion; however, these rectifier-based systems suffer from high conduction losses, poor power factor, increased total harmonic distortion (THD), and reduced overall efficiency. These drawbacks not only degrade charger performance but also introduce harmonics into the utility grid, resulting in additional losses and reduced reliability. To address these issues, this paper presents the design and analysis of a modified bridgeless AC–DC Landsman converter for EV charging applications. The proposed topology eliminates the conventional diode bridge rectifier, thereby reducing conduction losses and improving efficiency. The converter operates as a power factor correction (PFC) stage and provides a regulated DC output suitable for EV battery charging. The modified bridgeless configuration reduces the number of conducting devices in each switching cycle, which improves power quality and minimizes input current ripple. A PI controller is employed to regulate the DC-link voltage and maintain a constant output voltage. The proposed converter is modeled and simulated in MATLAB/Simulink using a 230 V single-phase AC input with a switching frequency of 20 kHz, and the output voltage is regulated to 48 V. Simulation results demonstrate improved power factor, reduced harmonic distortion, and stable output voltage. The input current waveform becomes nearly sinusoidal, and conduction losses are significantly reduced compared to conventional rectifier-based chargers. Therefore, the proposed modified bridgeless Landsman converter provides improved efficiency, reduced THD, better voltage regulation, and enhanced power quality, making it suitable for EV battery charging applications.

This project presents the design and development of a hybrid solar-hydro power generation system aimed at providing a sustainable, efficient, and reliable source of electricity for remote and rural areas. The system integrates a floating hydropower unit with a solar photovoltaic (PV) setup to ensure continuous power generation under varying environmental conditions. The hydropower unit utilizes a water turbine coupled with a DC motor which will act as generator to convert the kinetic energy of flowing water into electrical energy, while the solar panel supplements power generation during periods of low water flow or dry seasons. The generated DC power from both sources is regulated and stored in a rechargeable battery, which supplies power through a DC to AC inverter for general household and community use. An ESP32 microcontroller with integrated Bluetooth is used as a monitoring unit, replacing separate Arduino and ESP8266 modules used in earlier designs. This reduces circuit complexity, enhances processing efficiency, and enables real-time monitoring through the Serial Bluetooth Terminal. Additionally, a water level sensor is employed to continuously monitor river or canal levels and provide early flood alerts when unsafe conditions are detected. Alert message is sent via GSM Module. The combination of renewable energy sources, smart monitoring, and storage ensures a stable and uninterrupted power supply with enhanced safety. The proposed hybrid system effectively overcomes the limitations of existing standalone hydropower systems by adding solar energy support and battery backup. It demonstrates the potential of combining multiple renewable energy technologies with Real-time monitoring to achieve reliable, clean, and self-sustained power generation suitable for off-grid applications

Abstract The surge-current capability of integrated gate-commutated thyristors (IGCTs) under extreme fault conditions is critical for direct-current circuit breakers (DCCBs). In this study, the surge robustness and failure mechanisms of IGCTs were investigated through experiments and electro-thermal simulations. Results show that device failure initiates in the outermost ring, where high power loss combined with the negative temperature coefficient (NTC) of the on-state voltage drop (Von) leads to current crowding and localized thermal runaway. To mitigate this, a segmented-anode IGCT (SA-IGCT) with P+ strips embedded in the P emitter is proposed. Under high current conditions, these P+ strips inject additional holes into the drift region, enhancing conductivity modulation, reducing Von, and suppressing temperature rise and inter-ring nonuniformity. Simulations show that under a 40-kA peak surge current (ITSM), the SA-IGCT reduces the peak temperature by 33.9% and lowers Von by 39.6% compared to the traditional IGCT, while maintaining comparable blocking leakage current. These results demonstrate that the proposed SA-IGCT achieves a favorable trade-off between surge robustness and blocking performance. Its simple fabrication also makes it a promising candidate for high-voltage direct current (HVDC) applications.

ABSTRACT Abstract: In the modern world, the ever-increasing demand for energy, coupled with the growing challenges of waste management, has created a critical need for sustainable and eco-friendly solutions. Rapid urbanization, industrialization, and population growth have led to excessive generation of waste materials and a significant rise in energy consumption. Conventional energy sources such as fossil fuels are not only depleting rapidly but also contributing heavily to environmental pollution and global warming. In this context, the project titled “Energy Generation from Waste Material using Peltier Modules” presents an innovative approach to address both energy scarcity and waste disposal issues simultaneously. This project is based on the concept of thermoelectric power generation, which involves the direct conversion of heat energy into electrical energy without the use of moving parts. The working principle primarily relies on the Peltier effect, where a voltage is generated across a material when there is a temperature difference between its two sides. The core component used in this system is a Peltier module (thermoelectric generator), a semiconductor device capable of converting thermal gradients into electrical energy. The experimental setup consists of a combustion chamber, typically constructed using a heat-resistant metal enclosure such as aluminium. In this chamber, various types of waste materials—including paper, dry leaves, cardboard and other combustible waste—are burned to generate heat. This process not only helps in reducing waste volume but also produces a considerable amount of thermal energy that would otherwise be lost to the environment. The generated heat is directed toward the hot side of the Peltier module, while the cold side is maintained at a lower temperature using cooling techniques such as heat sinks, air cooling fans . The temperature difference between the hot and cold surfaces creates a movement of charge carriers within the semiconductor layers of the module, thereby producing direct current electricity. The magnitude of the generated voltage depends on the temperature gradient, making thermal management a key factor in optimizing system performance. To enhance the output, multiple Peltier modules can be connected in series to increase voltage and in parallel to increase current. The generated electricity can be stored in rechargeable batteries or directly utilized to power low-energy devices such as LED bulbs.

A Modified DC Power Electronics Transformer Based on Full-Bridge Converter

DC fault arcs comprise one of the most serious safety hazards in photovoltaic systems, and their danger far exceeds that of AC arcs. DC arcs lack a natural zero-crossing point, and their burning time can last from several seconds to several minutes, which is sufficient to ignite cable lines and surrounding combustibles, causing fires. To explore the characteristics and mechanism of the ignition of external combustibles by DC fault arcs, this paper, based on the theory of magnetohydrodynamics (MHD), constructed a three-dimensional numerical simulation model of a DC fault arc considering the coupling of electromagnetic, thermal, and flow fields. A DC fault arc experimental platform that can simulate the actual working conditions of photovoltaic systems was built to verify the accuracy of the model. Based on this, by integrating the complex pyrolysis model and the combustion reaction model, and selecting cotton fibers as the typical combustible indicator substances, as stipulated in the UL 1699 standard, a coupled simulation model for the ignition of solid combustibles by direct current fault arcs was established. The numerical simulation of the entire ignition process of the arc was realized, and the coupling mechanism of heat transfer, mass transfer, and chemical reactions during the ignition process was revealed. The research results of this paper fill a research gap in the numerical simulation of arc ignition caused by DC faults in photovoltaic systems, clarify the fire ignition risk patterns of DC fault arcs under different working conditions, and provide important theoretical support and technical references for the formulation of arc fire prevention strategies and the optimized design of fault arc protection devices for photovoltaic systems and other DC power systems.

Hybrid electric propulsion using a battery and a proton exchange membrane (PEM) fuel cell is a practical approach for improving the performance of electric vehicles under varying load conditions. A battery can respond quickly to sudden power demand, but repeated peak-current operation increases thermal stress and accelerates aging. A fuel cell can support longer operation and fast refueling, yet its dynamic response is slower during rapid load transitions. This work presents a prototype hybrid energy system that combines a lithium-ion battery pack and a PEM hydrogen fuel cell through DC–DC power converters and a common DC bus. A smart energy management controller based on the ESP32 monitors battery voltage, current, temperature, hydrogen pressure, and load demand, and then selects the operating mode in real time. The developed controller enables coordinated source sharing during peak load, cruising, charging, and fault conditions. An IoT monitoring interface is also used for remote supervision and fault indication. The prototype is intended to reduce battery stress, maintain DC bus stability, and improve operational safety in hybrid electric vehicle applications.Keywords—Hybrid electric vehicle, PEM fuel cell, lithium-ion battery, smart energy management, ESP32, DC–DC converter, IoT monitoring

This paper presents the design, implementation, and experimental validation of a real-time embedded photovoltaic (PV) emulator based on the two-diode model, using a dSPACE DS1103 platform for hardware validation. The proposed system aims to accurately reproduce the electrical behavior of PV modules under varying environmental conditions, including irradiance and temperature variations. The emulator architecture combines a lookup-table-based modelling approach with a programmable DC power source, enabling deterministic real-time execution and efficient implementation. A multi-level control structure is employed, integrating inner-loop regulation, model-based reference generation, and feedback control to ensure accurate tracking of the PV current–voltage (I–V) characteristics. Experimental results demonstrate that the emulator achieves high accuracy, with an approximation error of approximately 1.2% under standard operating conditions. The system exhibits stable dynamic behavior characterized by a time constant of approximately 0.5 s, with performance maintained across different sampling intervals and load conditions. Additional simulations confirm that the two-diode model preserves high accuracy over a temperature range of 15–60 °C, with deviations below 2%. The results highlight that the two-diode model provides an optimal trade-off between modelling accuracy and computational complexity for real-time embedded applications. The proposed emulator offers a flexible and reliable platform for laboratory validation of photovoltaic behavior and provides the foundation for future testing of maximum power point tracking (MPPT) algorithms, power electronic converters, and embedded control strategies under controlled conditions.

High-voltage direct-current (HVDC) power cables predominantly rely on cross-linked polyethylene as the key insulating material, and the performance is determined by the properties of low-density polyethylene (LDPE). The absence of a scientific basis for regulating direct-current (DC) conductivity via molecular chain architecture and crystallization has impeded the advancement of HVDC cable insulation. Herein, preparative temperature rising elution fractionation was employed to fractionate LDPE resins, obtaining fractions with more homogeneous chain structures. The results demonstrate that the DC conductivity of LDPE exhibits a skewed V-shaped dependence on molecular weight. For the samples investigated in this study, LDPE exhibits a minimum DC conductivity of approximately 7.5 × 10−15 S/m at 70 °C, corresponding to a molecular weight of about 130 kg/mol and a spherulitic morphology characterized by small spherulites with an average size of approximately 2 μm. The crystalline morphology, including lamellar dimensions and stacking manner, is tailored by molecular structure and modulates the charge transport in LDPE. Charge traps in pure LDPE are found to originate predominantly from the amorphous regions. The thinner amorphous thickness, together with small, non-banded spherulitic morphology, contributes to a lower trap density and deeper trap energy levels, thus ensuring optimal insulation performance. This study establishes a critical linkage between the chain structure, crystalline morphology, and charge transport behavior in LDPE, providing fundamental insights for material selection and the development of high-performance HVDC cable insulation.

To meet the dual requirements of selectivity and rapidity in fuse-based short-circuit protection for shipboard DC Integrated Power Systems (DC IPS), this paper proposes a novel coordination method. This approach employs an artificial neural network (ANN) to map the inherent time–current characteristic (TCC) curves of all fuses onto a unified time–current coordinate plane. Protection selectivity is then evaluated based on the relative positions of these curves, and by prioritizing fuses with shorter operating times, both selectivity and rapid fault clearance are achieved. Furthermore, through a mathematical analysis of the current relationships between faulted and non-faulted distribution circuits, the ANN is formulated to require only current and time data while maintaining robustness to moderate variations in short-circuit transition resistance. The effectiveness of the proposed method is validated using DC IPS cases of a hybrid passenger vessel and a pure electric sightseeing vessel. Compared with conventional coordination methods, the proposed method simultaneously accounts for the TCCs of protective devices and the influence of transition resistance on short-circuit current behavior. The case study results demonstrate that the proposed method achieves both selective and rapid protection, and shows strong potential for broader application in the coordination of multi-source DC power systems.