Conduction Mode Research Articles

Energy Enhancement for Grid Connection by Boost Inverter in Tripolar Operation with Novelty Quadcoupling Control

In this paper a single-phase differential boost inverter is presented that has two functions, first is boost up and second is active power quadcoupling without adding active power electronics components for smart grid system. There are three operating principals: First is pulse energy modulation which operates converter in continuous conduction mode (CCM), Second is quadcoupler which is designed by adding four boost converters and third is Tripolar technique which used to add two inductors and one capacitor for each boost converter. The proposed model consist of four boost converters in parallel with interleaving switching technique to get lower duty cycle. The energy is delivered to the quadcoupler through tripolar technique. When two grids are connected through DC to AC conversion the boost inverter can increase voltages on required demand. A Simulink model is designed that shows and proves properties of proposed system with high energy, high efficiency and power control with lower voltage stress.

Design of a High-Voltage Miniaturized Control System for Macro Fiber Composites Actuators

Macro Fiber Composites (MFCs) exhibit significant potential in active control applications. These include vibration control for unmanned aerial vehicle wings and helicopter rotors. However, the high-voltage drive requirements of MFCs present challenges. The miniaturization of the controller is a mandatory condition in order not to affect the overall space utilization. Thus, this paper presents a specialized miniaturized high-voltage control system designed specifically for MFC actuators. The proposed system employs a mixed analog-digital modulation method (ADM). This method precisely regulates a discontinuous conduction mode flyback switch-mode power supply operating in current mode. The system achieves an adjustable high-voltage output range of -500 V to 1500 V. The mixed control system consists of several components. These include a switching power supply, a voltage divider circuit, a bleeder circuit, and a digital controller. Additionally, this high-voltage control system integrates with a Simulink software environment. The system is compact and lightweight. It also features high load capacity, high power, and excellent dynamic response. Moreover, it offers real-time control capabilities. Experimental validation on a high-aspect-ratio wing demonstrates that this control system achieves a vibration reduction effect of 65%. The miniaturized control system provides a valuable research base for vibration control studies.

High gain multi-stage DC-DC boost converter using improved switched-inductor network with reduced voltage stress

ABSTRACT This article proposes a high-gain DC-DC boost converter employing an improved switched inductor (ISI) network coupled with CLD (capacitor-inductor-diode) cell (ISI-CLD-BC). The ISI network is further extended to an n-stage configuration, providing a multistage structure that enhances the attractiveness of the proposed converter for achieving high voltage gain. By Integrating a CLD cell at the load side, voltage stress across the active switch is reduced, enabling utilisation of lower-rated MOSFETs with reduced on-state resistance, thereby enhancing cost-effectiveness as well as efficiency. Furthermore, the CLD cell has the advantage of increasing the output voltage. The proposed converter’s steady-state performance in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is fully studied. Furthermore, the efficiency is analysed by evaluating different power losses of different elements. A small-signal model is derived for the proposed converter to evaluate the non-minimal phase condition followed by a PI controller design under closed-loop conditions. An exhaustive comparative study is conducted between the proposed converter and recently developed high-gain converters by considering various performance indices. Finally, the proposed converter is simulated in MATLAB/Simulink software and an experimental setup is created and tested to ensure its validity and efficacy.

Modified input-to-output and control-to-output transfer functions of a non-ideal buck converter working in discontinuous conduction mode

Small-signal models of a buck converter working in the discontinuous conduction.mode that are available in the literature usually can be divided into those which contain.a single pole and refer to non-ideal converters and those that describe ideal converters and.contain two poles. Even though the models are noticeably different they have been validated.through simulations and measurements, which suggests both of them are correct. The.purpose of this paper is to provide a comprehensive comparison of the existing models with.transient simulations done in OrCAD software and through measurements, to show that both.of the mentioned models are true for a specific set of converter parameters, and to propose.a two-pole, control-to-output and input-to-output transfer functions of a non-ideal buck.converter, that can be used in any buck converter working in discontinuous conduction mode.

Effects of wire feeding direction on the deposition characteristics of 316L stainless steel in laser-directed energy deposition

This study investigates the effect of wire feeding direction on the microstructure of 316 stainless steel during the laser-directed energy deposition (L-DED) process. The process parameters were optimised by varying the scan speed, laser power, and wire feed rate to identify a common parameter set for all feed directions to give desired weld bead geometries. The identified process parameter window has shown that the conduction mode is preferred over the balling and keyhole modes. Comprehensive microstructural characterization using optical and electron microscopy has revealed that for the same parameters, the front wire feed had higher penetration, while the back wire feed had a wider bead with optimal penetration. The current findings are of significance for advancing wire-L-DED additive manufacturing for more complex component designs.

Optimal control of nonlinear dynamics in Buck converters using spotted hyena optimizer: a computational and experimental study

Power electronics circuits are well-known for their nonlinear dynamics, which arise from cyclic switching between the circuit topologies. The aim of this work is the exploration and shifting of the nonlinear phenomena exhibited by Buck converters, this converter is selected to be voltage mode controlled (VMC) and functioning in continues conduction mode (CCM) through a mathematical model developed and tested in MATLAB. Through systematic changes in the converter's variables, it is shown that the switching converter may exhibit abnormal phenomenon and undesirable comportment witch bifurcation, quasi-periodic, and chaotic oscillations. The proposed method Spotted Hyena Optimizer (SHO) is used to control the chaotic characteristics of a buck converter by obtaining optimal parameters for the PID controller. This is done by reducing the difference between the desired value of the output voltage and the measured values. To validate the proposed solution, a dSPACE-controlled Buck converter prototype is constructed and subjected to experimental studies. The proposed method will be validated through the results of both the computational and experimental.

Advancing renewable energy: A quadratic high-efficiency high gain step-up DC/DC converter

Presenting a new high-gain converter that incorporates a coupled inductor, this paper offers a range of advantages over existing designs. The circuit features a simple structure with two cascade semi-stages, two power switches operating in sync, and a coupled inductor. It provides an extensive output voltage range, ensures continuous input current with minimal ripple, maintains positive output voltage polarity, and follows a standard ground configuration. These features make it well-suited for various applications, particularly in photovoltaic systems. Additionally, the voltage stress across each power switch is significantly lower than that of other boost converters, allowing for the selection of power MOSFETs with reduced drain-source ON resistance to ensure high efficiency. This research presents comprehensive assessments of the steady-state and stress conditions as well as thorough comparisons with other similar converters operating in continuous conduction mode. Theoretical advantages of the proposed circuit design are further reinforced by experimental results obtained from a 200-W step-up 25–370 V arrangement.

Spatter detection and tracking in high-speed video observations of laser powder bed fusion

Purpose In laser powder bed fusion (L-PBF) additive manufacturing, spatter particles are ejected from the melt pool and can be detrimental to material performance and powder recycling. Quantifying spatter generation with respect to processing conditions is a step toward mitigating spatter and better understanding the phenomenon. This paper reveals process insights of spatter phenomena by automatically annotating spatter particles in high-speed video observations using machine learning. Design/methodology/approach A high-speed camera was used to observe the L-PBF process while varying laser power, laser scan speed and scan strategy on a constant geometry on an EOSM290 using Ti-6Al-4V powder. Two separate convolutional neural networks were trained to segment and track spatter particles in captured high-speed videos for spatter characterization. Findings Spatter generation and ejection angle significantly differ between keyhole and conduction mode melting. High laser powers lead to large ejections at the beginning of scan lines. Slow and fast build rates produce more spatter than moderate build rates at constant energy density. Scan strategies with more scan vectors lead to more spatter. The presence of powder significantly increases the amount of spatter generated during the process. Originality/value With the ability to automatically annotate a large volume of high-speed video data sets with high accuracy, an experimental design of observed parameter changes reveals quantitively stark changes in spatter morphology that can aid process development to mitigate spatter occurrence and impacts on material performance.

Demonstration of normally OFF beta-gallium oxide monolithic bidirectional switch for AC switching applications

In this work, we report on the beta-gallium oxide (β-Ga2O3) monolithic bidirectional switch. The as-fabricated switch works on enhancement mode operation with a threshold voltage of ∼4 V. Maximum drain current density of 1.93 mA/mm is obtained with a drain voltage of 5 V. The bidirectional switch in a bidirectional mode has an ON/OFF current ratio of ∼107 with ON-resistance of 1.11 and 1.09 kΩ · mm in forward and reverse direction, respectively. However, in diode mode, the device shows an ON/OFF current ratio of 1.6 × 108 and 1.4 × 108 in forward and reverse conduction modes, respectively. The fabricated β-Ga2O3 monolithic bidirectional switch is then used to chop a 60 Hz Alternating Current signal at a chopping frequency of 1 kHz, indicating its potential applications in a range of converters.

High-performance front end PFC controller design for light electric vehicle charger application

Power factor correction (PFC) boost converters operating in CCM (continuous conduction mode) typically utilize average current mode (ACM) control alongside a LPF (low-pass filter) to reduce the impact of double line frequency ripple on the current loop. However, the LPF limit the voltage loop bandwidth in ACM-regulated converters, resulting in sluggish dynamic response. Additionally, zero-crossing distortion (ZCD) often occurs in the current control loop due to inaccuracies in tracking the reference current at the zero crossing point of the waveform. To address these challenges, this paper proposes a feed-forward control strategy that utilizes supply voltage and output current, effectively eliminating the need for an LPF and enhancing transient response. The voltage loop is tuned using the conventional Z-N method, while the Grey Wolf Optimization (GWO) technique is employed to optimally tune the gain parameters of the current controller (KPi and KIi). This approach effectively reduces reference tracking errors and mitigates ZCD, offering a balance between simplicity and performance. The proposed method is simple, offering fast transient and steady-state response, low THD, near-unity PF, and tight voltage regulation under fluctuating conditions. The effectiveness of this approach is validated through MATLAB/Simulink simulations, and hardware verification is conducted using a 500 W laboratory prototype controlled by a dSPACE 1104 digital controller.

A New Three‐Port DC–DC Converter: Analysis, Design, and Verification for Hybrid Energy Systems

ABSTRACTA research study on the three‐port DC–DC converters is done in this article. The proposed converter is a power electronic unit with a low‐voltage, high‐voltage, and battery port. The power of the input ports can be transferred to the output port simultaneously and individually. In this converter, the power can flow bidirectional. In other words, the battery can be charged not only by the low‐voltage port but also by the returned energy from the high‐voltage port. Hence, the proposed converter can operate in step‐up and step‐down modes. Continuous input current, the low voltage stress on semiconductors, and the low count of the devices are other advantages of the converter. These features and the benefits mentioned above make the proposed converter proper for hybrid energy systems. This converter is analyzed in continuous conduction mode, resulting in mathematical equations. To validate these theoretical analyses, a laboratory scale of the converter performs at 50 kHz, 200 W, and 115 V.

Enhanced High‐Gain Switched Capacitor DC–DC Converter Optimizing Renewable Energy Integration

ABSTRACTA novel high‐gain switched capacitor (HGSC) DC–DC converter for carbon neutral energy applications is presented in the scientific paper. It consists of two MOSFET switches, and utilization of a simultaneous switching approach for the switches enables simplified control. The switched capacitor (SC) technique is utilized to extract high gain from the proposed HGSC topology; the basic idea is periodic charging and discharging of the capacitor. The proposed HGSC topology operational mode is carried out in Continuous Conduction Mode (CCM) along with the steady‐state analysis, and different switching stages are discussed in detail. Then, an analysis is carried out to demonstrate the proposed HGSC converter's special feature with other high‐gain converters. An averaging state‐space technique is used to determine the suggested converter's dynamics performance, and a small signal analysis is used to verify its stability. Furthermore, the HGSC topology is thoroughly analyzed in terms of power losses. For comparing the practical efficiency of the designed converter, nonidealities voltage gain is derived. The maximum efficiency of 96.7% is obtained at 150 W output power with the help of the dSPACE 1104 controller. Whenever the HGSC converter is fed with an input voltage supply of 20 V. It generates output voltages between 140 and 240 V. Extensive experimental investigation is carried out on a 200 W laboratory prototype model to verify the practicability and feasibility of HGSC DC–DC converter topology.

GaN-Based Interleaved Four-level Flying Capacitor Triangular Conduction Mode (TCM) Converter with Coupled Inductors

GaN-Based Interleaved Four-level Flying Capacitor Triangular Conduction Mode (TCM) Converter with Coupled Inductors

Influence of adjustable ring modes on molten pool behavior and microstructure of Al–Si coated boron steel in fiber laser welding

The influence of adjustable ring modes on the phase transition and microstructural evolution in conduction mode laser welding of Al–Si coated boron steel was investigated. Distinct geometric variations and molten pool behavior were observed through a ring-shaped beam effect. The ring beam introduced by ring-beam-mode (RBM) and dual-beam-mode (DBM) laser welding inhibited Al segregation into the fusion zone (FZ). The ring beam caused the Al molten particles to be driven towards the outer boundaries of the weld pool. A ring-beam-mode (RBM) and a dual-beam-mode (DBM) laser welding inhibited Al segregation into the FZ, resulting from a minimal temperature gradient and extension of the solidification time. Phase transition calculations demonstrated that a mount of residual ferrite within the FZ is significantly correlated with the Al concentration at specific temperature points, indicating a predominant role of a central-beam-mode (CBM) FZ in δ-ferrite formation. The RBM and DBM effectively suppressed Al segregation into the FZ, leading to a reduction in ferrite formation and the development of a refined microstructure characterized by a uniform and high density of geometrically necessary dislocations. Electron backscattered diffraction (EBSD) analysis revealed a higher proportion of low-angle grain boundaries in the RBM and DBM, attributed to the unique thermal distribution induced by the ring beam. These findings highlight the critical role of beam mode in tailoring the microstructure and properties of laser welds in Al–Si coated boron steel.

Impacts of conduction and radiation modes on freezing within an enclosure utilizing hybrid nanoparticles by means of mathematical modeling

Impacts of conduction and radiation modes on freezing within an enclosure utilizing hybrid nanoparticles by means of mathematical modeling

Modelling and DPWM control of continuous switched boost inverter

ABSTRACT In this paper, a new type of three-phase continuous switched boost inverter (CSBI) is proposed. The proposed inverter has a new impedance network that can obtain a high voltage boost ratio. It also can make the system work in continuous conduction mode (CCM). The shoot-through is allowed in the operating mode of the CSBI, which eliminates the dead time and leads to better EMI immunity. The modified discontinuous pulse-width modulation (DPWM) strategy is proposed to operate the CSBI. Compared with the space vector pulse-width modulation (SVPWM) method, the new modulation strategy can reduce the switching loss effectively. Meanwhile, the state space averaging method is used to design the inverter structure and calculate the impedance parameters. To investigate the dynamic performance of the CSBI impedance parameters, the small signal model analysis is used. A test bench of CSBI is built in laboratory. The operating strategy and the theoretical analysis of the proposed inverter are validated by the results of simulation and experiment.

Study of patterns and mechanisms of combustion of powdered and granulated T-C-B system

Experimental studies of the combustion patterns of the ternary system (100 – x)(Ti + C) – x(Ti + 2B) of bulk density in powder and granular form used for the synthesis of composite ceramics TiC–TiB2 were carried out. The study shows that the dependence of the powder mixture combustion rate on the Ti + 2B content has a non-monotonic character, which is associated with the influence of impurity gas release on the combustion process. By removing the influence of impurity gas by granulation, a monotonic dependence with two characteristic sections was obtained. For the granulated mixture, an increase in the Ti + 2B content 60 wt. % leads to a change from the conductive combustion mode to the convective one, accompanied by a sharp increase in the combustion rate. For the conductive combustion mode, the combustion rate of the substance inside the granule and the combustion transfer time from the granule to the granule were determined, which allowed us to estimate the inhibitory effect of impurity gas release on the combustion rate of powder mixtures of different composition. For the convective combustion mode, it was shown that a decrease in the content of the gasifying additive in the mixture (granulation with ethyl alcohol) led to an unexpected result: an increase in the combustion rate of the mixture. For compositions with (Ti + 2B) 60 wt. % the combustion rate with counter filtration of impurity gases was determined for the first time, which made it possible to estimate the front rate increase according to the filtration combustion theory. According to XRD results, the combustion products of all compositions contain only two main phases TiC and TiB2.

Optimization Control Strategy for Light Load Efficiency of Four-Switch Buck-Boost Converter

The four-switch buck-boost (FSBB) converter usually adopts a pseudo-continuous conduction mode (PCCM) soft switching (ZVS) control strategy, but there is a problem with the low efficiency of FSBB converters under light loads. Firstly, the constraints that the control variables of the FSBB converter need to satisfy are analyzed, and it is pointed out that the fixed frequency constraint is not necessary. Then, the switching frequency is used to control the degree of freedom, and the quantitative relationship between the FSBB converter loss and the switching frequency is obtained. Finally, for different input voltages and loads, the switching frequency corresponding to the minimum power loss is calculated offline. By optimizing the switching frequency, the light-load efficiency of the FSBB converter is improved. A prototype with an input voltage range of 210 V–330 V, an output voltage of 270 V, and an output power of 3 kW was developed. The loss was reduced by 15% at 20% load, and the peak efficiency of the converter reached 99.23%. The experimental results verified the effectiveness of the proposed control strategy.

High efficiency AOT-controlled boost converter with pseudo-constant switching frequency

An on-time generator for boost converters is proposed to achieve an adaptive on-time (AOT) control with pseudo-constant frequency in continuous conduction mode (CCM). Since the first-order parasitic effect of the components and devices is considered in the design of the on-time generator, the switching frequency (fsw) variation of the boost converter in CCM can be better suppressed with the load current (ILOAD), input voltage (VIN) and output voltage (VOUT) changes, which can effectively solve the EMI noise problem. In addition, the idea of capacitor pre-charging is applied to simplifying circuit complexity. Meanwhile, an on-demand modulation strategy is applied to improve the conversion efficiency. Simulation results show that the boost converter based on the proposed on-time generator can realize the fsw variation of 0.4 % in case of 200 mA ILOAD change. Moreover, the VIN may range from 0.8 to 1.5 V, the VOUT is set to 1.8 V, and the peak efficiency of the simulation is 96.9 %.

A new forward‐flyback converter without right half plane zero

AbstractDue to its unique features, the flyback converter is widely used to convert DC to DC power. This converter has a non‐minimum phase (NMP) dynamic behavior, which is one of its most significant disadvantages. By changing the topology of the flyback converter to a forward‐flyback (FF) converter, the dynamic behavior of the converter can be minimum phase (MP) while the main advantages of the flyback converter such as isolation of the output from the input and simple topology are maintained. This article proposes an innovative FF converter topology by doubling the forward path and adding only one diode and one capacitor. In addition to better dynamic behavior, the proposed double FF (DFF) converter has the same advantages as the conventional FF converter. A new method is used to obtain the transfer function of the output voltage to the duty cycle of the proposed converter. The converter is designed in continuous conduction mode (CCM) with minimum phase dynamics. Finally, simulation and experimental results of both conventional FF and the proposed DFF converters are obtained and compared to validate the superiority of the proposed converter.