Conventional Topology Research Articles

A novel voltage lifting technique of switched-inductor cell based modified LUO converter topology for water pumping system

The persistent exhaustion of traditional energy sources with their impacts on the environment has been initiating a significant interest in a selection of renewable-energy sources (RES) based water-pumping system. Among several renewable sources, solar-PV is the most promising and practical source for water-pumping applications that can be easily installed on a building's roof. The available solar-PV energy is integrated to AC electric motor through front-end DC-DC boost converter topology. Among the various DC-DC converter topologies, a novel switched-inductor type modified LUO converter has been proposed for solar-PV powered water pumping system. The proposed switched-inductor type modified LUO (SI-MLUO) converter have simple structure which delivers high voltage gain with low leakage currents, low current ripples, reduced voltage spikes, low dv/dt stress and high efficiency over the several conventional DC-DC converters. The operating modes and performance of proposed SI-MLUO converter topology is verified by using MATLAB/Simulink tool, simulation results are validated with conventional topologies.

An Improved DC Power Electronic Transformer Based on Voltage Balancing Converter for Bipolar Distribution System

This paper proposes a bipolar dc power electronic transformer (DCPET) with monopole fault operation capability for medium voltage / low voltage DC (MV / LVDC) distributions. Compared with the conventional bipolar LVDC topology, the proposed DCPET considers the reduced number of switching devices and the normal operation under monopole faults, which improves power supply reliability. The dc fault ride-through (FRT) strategy is further proposed in this paper to increase the power supply reliability under LVDC short-circuit faults. To reduce the short-circuit current and maintain the LVDC voltage, the switching device reversely series with the capacitor is blocked after the fault. Thus, the fault current is restricted, and power supply recovery time after fault clearance is reduced. Moreover, the LLC resonant converter adopting phase shift control outputs stable fault criterion current to assist the fault location and removal for the protection system. Finally, a downscaled prototype is built to verify the proposed topology and FRT strategy by experiments.

Sensorless Capacitor Voltage Detection Method of Cascaded H-Bridge STATCOM Based on Special Switching Mode Identification

The cascaded H-bridge (CHB) static synchronous compensator (STATCOM) has been widely used in wind farm and conflux station. As the grid-connected voltage increases, the number of cascaded CHB proportionately increases. In order to achieve the capacitor voltage balance, it is necessary to independently detect the capacitor voltage of all H-bridge cells, which raises the cost of capacitor voltage detection. To solve this problem, the mapping relationship is studied between the converter output voltage and capacitor voltages by analyzing carrier phase-shifted sinusoidal pulse width modulation technique (CPS-SPWM), and special switching mode is firstly found. Based on the above finding, without changing the conventional CHB topology, an improved sensorless detection method is proposed to solve the problems of detection error, large computation burden and the application limitation in existing sensorless detection methods. Compared with conventional sensor detection, this method not only saves DC voltage sensors and data transmission channels but also suppress the third harmonics in the converter current. Finally, the effectiveness of the detection method applied on CHB STATCOM is proved by simulation and experiment.

High voltage gain switched z‐source inverter with low current stress

AbstractThis paper proposes a switched Z‐source inverter with high voltage gain and low current stress on elements. Also, a new switching method corresponding to the proposed topology is introduced. This method is based on the usual Maximum Constant Boost (MCB) method. Hence, it has the advantages of the MCB method, such as low voltage stress on the inverter switches and high voltage gain. Also, eliminating part of the inverter's switching in this modulation method improves the inverter's efficiency. In addition to the Shoot‐Through (ST) duty cycle, another variable (N) affects the inverter's boost factor in this switching method. The proposed inverter's dynamic analysis shows that introducing N in the modulation method improved the dynamic characteristic of the inverter. Also, this variable as a control input can stabilize the dc side of the inverter in the closed‐loop control of the inverter. For the proposed topology, steady‐state analysis, dynamic analysis, elements design and efficiency calculation are performed. Also, the proposed topology is compared with the conventional topologies regarding boost factor, the number of elements, current stress on elements and efficiency to show its superiority. Finally, the experimental results are presented to verify theoretical discussions.

Differential-Evolution-Assisted Optimization of Classical Compensation Topologies for 1 W Current-Fed IMD Wireless Charging Systems

Implantable medical devices (IMDs) necessitate a consistent energy supply, commonly sourced from an embedded battery. However, given the finite lifespan of batteries, periodic replacement becomes imperative. This paper addresses the challenge by introducing a wireless power transfer system designed specifically for implantable medical devices (IMDs). It begins with a detailed analysis of the four conventional topologies. Following this, the paper provides a thorough explanation for choosing the PS topology, highlighting its advantages and suitability for the intended application. The primary parallel capacitance necessitates power from current sources; thus, a Class-E amplifier was implemented. Additionally, the selected circuit was engineered to deliver 1 W at the biocompatible resonance frequency of 13.56 MHz. The delineation of the resonance parameters hinges on multifaceted solutions, encompassing bifurcation-free operation and the attainment of peak efficiency. To ensure the feasibility of the proposed solution, a Differential-Evolution-based algorithm was employed. The results obtained from simulation-based evaluations indicated that the system achieved an efficiency exceeding 86%. This efficiency level was maintained even in the face of frequency fluctuations and variations in the coupling between the coils, thereby ensuring stable operational performance. This aligns seamlessly with the specified application prerequisites, guaranteeing a feasible and reliable operation.

Signal-Division-Aware Analog Circuit Topology Synthesis Aided by Transfer Learning

Compared with conventional analog circuit topology synthesis methods, the deep-reinforcement-learning-(DRL)-based method features much higher synthesis efficiency while possessing the merit of strong generalization capability. However, this method cannot synthesize operational amplifiers that involve signal division. To address this critical limitation, this paper presents new synthesis rules to guide the DRL-based synthesis process. In addition, to meet various design specifications requested by users, we further develop a smart circuit synthesis system, which can robustly return a solution (i.e., a feasible circuit topology with detailed device sizes) right away as long as the input design specifications are reasonable. A transfer learning scheme is proposed to reduce the computation overhead of training this system. The experimental results show the efficacy of our smart circuit synthesis system and transfer learning scheme, confirming an advancement over the state-of-the-art approaches.

Coordinated Optimization of Emergency Response Resources in Transportation-Power Distribution Networks Under Extreme Events

The proliferation of electric vehicles (EVs) and the increasing interdependence across power distribution networks (DNs) and transportation networks (TNs) have increased the complexity and vulnerability of the two systems in extreme circumstances. As the interdependence of two infrastructures tightens over time, it is viewed as a dire necessity to strengthen the resilience of the coordinated transportation-power distribution networks (TDNs) against natural disasters. This paper constructs a coordinated optimization method of TN traffic link reversing, DN line switching, and fast charging pile management, to improve the TDN performance in the emergency response stage after disasters. A dynamic TN model and a multi-period DN model are integrated in TDN modeling to capture flow propagations and state variations among time intervals. The coordinated optimization for TDN emergency response is designed as a mixed-integer nonlinear programming (MINLP) problem with high-order objective functions and nonlinear constraints to minimize TN travel costs and DN active and reactive power shortages. An accuracy-aware adaptive piecewise linearization approach combined with Gray code-based encoding is utilized to improve the computational efficiency for solving the TDN optimization problem. Numerical simulations show that the TDN performance is enhanced by coordinating various DN and TN resources, as compared with those of separate and conventional topology controls. The proposed TDN solution method has significantly reduced the computation time for managing extreme conditions while guaranteeing the accuracy of the results as compared with those of the nonlinear model and the linearized model by uniform piecewise linearization.

DMF-TONN: Direct Mesh-free Topology Optimization using Neural Networks

We propose a direct mesh-free method for performing topology optimization by integrating a density field approximation neural network with a displacement field approximation neural network. We show that this direct integration approach can give comparable results to conventional topology optimization techniques, with an added advantage of enabling seamless integration with post-processing software, and a potential of topology optimization with objectives where meshing and Finite Element Analysis (FEA) may be expensive or not suitable. Our approach (DMF-TONN) takes in as inputs the boundary conditions and domain coordinates and finds the optimum density field for minimizing the loss function of compliance and volume fraction constraint violation. The mesh-free nature is enabled by a physics-informed displacement field approximation neural network to solve the linear elasticity partial differential equation and replace the FEA conventionally used for calculating the compliance. We show that using a suitable Fourier Features neural network architecture and hyperparameters, the density field approximation neural network can learn the weights to represent the optimal density field for the given domain and boundary conditions, by directly backpropagating the loss gradient through the displacement field approximation neural network, and unlike prior work there is no requirement of a sensitivity filter, optimality criterion method, or a separate training of density network in each topology optimization iteration.

Performance investigations of five-level reduced switches count Η-bridge multilevel inverter

Introduction. This research paper describes a simple five-level single-phase pulse-width modulated inverter topology for photovoltaic grid applications. Multilevel inverters, as opposed to conventional two-level inverters, include more than two levels of voltage while using multiple power switches and lower-level DC voltage levels as input to produce high power, easier, and less modified oscillating voltage. The H-bridge multilevel inverter seems to have a relatively simple circuit design, needs minimal power switching elements, and provides higher efficiency among various types of topologies for multi-level inverters that are presently accessible. Nevertheless, using more than one DC source for more than three voltage levels and switching and conduction losses, which primarily arise in major power switches, continue to be a barrier. The novelty of the proposed work consists of compact modular inverter configuration to connect a photovoltaic system to the grid with fewer switches. Purpose. The proposed system aims to decrease the number of switches, overall harmonic distortions, and power loss. By producing distortion-free sinusoidal output voltage as the level count rises while lowering power losses, the constituted optimizes power quality without the need for passive filters. Methods. The proposed topology is implemented in MATLAB/Simulink with gating pulses and various pulse width modulation technique. Results. With conventional topology, total harmonic distortion, power switches, output voltage, current, power losses, and the number of DC sources are investigated. Practical value. The proposed topology has proven to be extremely useful for deploying photovoltaic-based stand-alone multilevel inverters in grid applications.

Electromechanical Actuator-Based Solution for a Scissor Lift

Electrification and hybridization in non-road mobile machinery have attracted considerable attention in recent years. Normally, these green solutions concentrate on drivetrains, slowly penetrating to the implements or, as they are commonly known, working hydraulics. The primary difficulties associated with drivetrains were successfully addressed through the implementation of electric solutions and the utilization of hydraulic configurations. However, existing hydraulics solutions are typically challenged by innovative pure electromechanical solutions to perform the same work. Therefore, the purpose of this study is to illustrate the impact of replacing a conventional hydraulic topology with an electromechanical actuator (EMA) solution. This paper presents a case study of the electrification of a scissor lift, which was evaluated by simulation and experimental works from an energy perspective. The simulation study demonstrated the energy consumption and power requirements in conventional hydraulic (i.e., non-efficient in comparison with advanced systems) and EMA-based topologies for a single lifting cycle. Finally, an average of 35–50% of the consumed energy was saved, which is confirmed based on a completed simulation study case for the scissor lift application.

Feasibility analysis of 2-dimensional permutation vector optical code division multiple access passive optical network

This paper analyzes the feasibility of a 2-dimensional (2D) permutation vector (PV) optical code division multiple access (OCDMA) passive optical network (PON) in terms of transmission capacity, network reliability, power budget, and the number of subscribers. The proposed PON is built with a novel 2D PV-OCDMA code having ideal auto- and cross-correlation properties. Furthermore, a ring-based topology at the feeder level and a tree-based topology at the distribution level are utilized to support ubiquitous computing. The proposed architecture also employs multiple remote nodes at the feeder level to facilitate adequate power budget and cardinality for high-capacity applications. Simulation results indicate that the proposed PON elevates system transmission capacity by eliminating phase-induced intensity noise and multiple access interference. Furthermore, reliability analysis using mathematical formalism demonstrates that the proposed architecture can provide a connection availability of ≈0.099993 (5 nines), which is significantly higher than the conventional tree-based topology. Power budget analysis also determines that the proposed PON can support well above 320 subscribers at adequate receiver sensitivity and optical network terminals (ONTs) per remote node.

Millimeter-Wave single-pole-double-throw switch design with Stacked-FET topology using network cascading analysis

In this paper, the correlation between the key performance of the shunt-type single-pole-double-throw (SPDT) switch circuitry and the intrinsic device parameters is theoretically investigated by network cascading approach. Through rigorous analysis, we concluded that the intrinsic device parameters such as the gate-to-drain capacitance (Cgd) have direct impact on the performance due to the scaling of the gate length. The analysis results were verified by the implementation of an SPDT switch at millimeter-wave frequency using stacked-FET topology. An input power at 1-dB compression point (P1dB) of greater than 30 dBm was measured from 15 to 35 GHz, exhibiting an enhancement of 6-dB in comparison with the conventional topology.

An 80-GHz DCO utilizing improved SC ladder and promoted DCTL-based hybrid tuning banks

An 80-GHz DCO based on modified hybrid tuning banks is introduced in this paper. To achieve sub-MHz frequency resolution with reduced circuit complexity, the improved circuit topology replaces the conventional circuit topology with two binary-weighted SC cells, enabling eight SC-cell-based improved SC ladders to achieve the same fine-tuning steps as twelve SC-cell-based conventional SC ladders. To achieve lower phase noise and smaller chip size, the promoted binary-weighted digitally controlled transmission lines (DCTLs) are used to implement the coarse and medium tuning banks of the DCO. Compared to the conventional thermometer-coded DCTLs, control bits of the proposed DCTLs are reduced from 30 to 8, and the total length is reduced by 34.3% (from 122.76 to 80.66 μm). Fabricated in 40-nm CMOS, the DCO demonstrated in this work features a small fine-tuning step (483 kHz), a high oscillation frequency (79–85 GHz), and a smaller chip size (0.017 mm2). Compared to previous work, the modified DCO exhibits an excellent figure of merit with an area (FoMA) of –198 dBc/Hz.

Modeling, testing, and optimization of novel lattice structures for enhanced mechanical performance

Cellular materials have drawn increasing interest in numerous applications due to their promising specific stiffness, strength and energy absorption capacity. In this work, a variety of rather novel lattice topologies pertinent to additive manufacturing are derived and examined. A number of these are derived by free-domain and constrained domain topology optimization procedures, while others are inspired by the triply periodic minimum surface (TPMS) sheet-based topologies. The topology optimization module utilized a single objective function of minimizing strain energy under linear elastic conditions. A total of fifteen different lattice topologies are investigated numerically, including both novel and conventional topologies (e.g. strut-based lattices) and their effective elastic properties are determined with respect to relative density through finite element analysis (FEA). Based on the preliminary FEA results, a number of these topologies are selected of which tessellated lattice structures are fabricated through laser powder bed fusion (LPBF) additive manufacturing technique out of Nylon thermoplastic material. The tessellated lattice structures are experimentally tested in compression and their mechanical performance, including uniaxial modulus, yield strength, and energy absorption capacity (EAC), is assessed. FEA simulations have been conducted using an elastic-plastic constitutive model for the Nylon base material. Both the experimental and numerical results reveal that the mechanical performance of the novel tube-based TPMS lattice P-100 and the combined loading (CL) topology derived through free-domain topology optimization surpasses all other topologies. P-100 uses a primitive TPMS with equal-length tubular connections in each direction, where the tubular length percentage compared to the primitive lattice size is 100%, while CL lattice topology is a free domain topology optimized under compressive loads on the centers of faces, edges, and vertices toward the center. The innovative lattice topologies proposed in the current study, particularly the P-100 and CL topologies, can become crucial in applications where it is necessary to improve the energy absorption capacity, such as sandwich panel cores, supports, and infills for 3D printed components.

Maximum power enhancement in solar PV modules through modified TCT interconnection method

This article presents a narrativemove towards for maximal power augmentation in poly-crystalline solar photovoltaic (PV) modules through the modified Total Cross Tied (TCT) interlinkconnection method. Worldwide, the cost of coal has increased after a pandemic rebound in industrial activity and it leads to demand for electricity. The maximum power extraction from sustainable energy sources plays a vital role as they are ample, eco-friendly, harmless, and won’t run out. Due to shading effects like the transition of clouds and tree shadows, the output power generated from the solar photovoltaic array is reduced uptill 60%. Several methodologies of array formation and reconfiguration strategies were developed to overcome the partial shading effects. In this proposed method, PV cells in modules are tied via modified TCT fashion with a bypass diode through each row. Real-time experimental analysis is performed with 4 × 4 cell connections. The current (I)-(V)voltage and Power(P)-(V) voltage characteristics are obtained under normal and various partial shading conditions. According to our proposed method, the percentage power enhancement achieved by row-wise partial shading increases from 10% to 60%, approximately 83.64, 82%,80%, 74.29%, 70%, and 64%. According to the conventional topology, the maximum fill factor is 0.28 in columnwise 25% shading ratio, whereas the proposed modified TCT PV array has a fill factor of 0.53, 89% higher. Compared to the proposed pattern, which has a maximum performance ratio of 0.86 for 10% shading condition. The modified TCT interconnected PV module connection extracts a maximum of 50% increased output power when compared to conventional PV modules. The performance of the projected modules is also examined in a one kW PV array.

Practical Implementation of High-Efficiency Multiple-Input Converter Embedding Renewables and Energy Storage for DC-Microgrid Applications

The use of high frequency power converters to enhance power density and energy efficiency has become widely used in grid-connected hybrid DC microgrids. This paper presents a new modularized high frequency DC-link integration methodology that connects multisource renewable energy sources involving battery energy storage system (BESS) to the AC-grid. A grid-tie-inverter with a line inductor is introduced to control the active-reactive power flow. To minimize the converter physical size with improved system efficiency, a high frequency-based front-end multisource bridgeless boost (MBB) architecture is proposed here. A direct-mount decoupling snubber capacitor and a soft switching are used to reduce the switching losses resulting from the high-frequency operation. The performance of the proposed system is investigated. A direct digital approach is used to design the system controller in MATLAB/Simulink R2022a environment. To validate the system performance, a 10 kW multi-source grid-connected experimental setup with dSPACE-1104 controller is constructed, tested, and compared with other conventional topologies. The test results verify the proposed topology effectiveness for hybrid grid-connected renewable energy resources integration.

Evaluation of CHB MLI based shunt APF using low pass filter and self-tuning filter

The increasing demand for high-rating power supply in the distribution system causes the conventional inverter topology, six step voltage source inverter (SSVSI) unsuitable for being applied as active power filter (APF). Multilevel inverter (MLI) is generally the best suitable inverter for APF, but not all types of MLI can be used for high-voltage applications. Among the MLIs topology, cascaded H-bridge (CHB) is the best choice since it can produce output voltage more than twice the amount of DC source. Moreover, CHB MLI topology uses fewer power devices and is simple in design. Low pass filter (LPF) is a common method used for harmonic extraction in this controller. However, this method faces various problems, such as an additional need for phase lock loop (PLL) algorithm and slow transient and steady-state responses. Therefore, self-tuning filter (STF) is introduced as a new filtering method to overcome this problem. This paper evaluates CHB MLI's performance for APF using STF as a harmonic extraction. The model was developed and verified in MATLAB/Simulink. The results show that harmonic extraction using STF performs better total harmonic distortion (THD) than conventional LPF. Nevertheless, both algorithms produce THD below 5%, defined as the permissible value stated in IEEE 519.

Implementation of Power Factor Correction using Asynchronous Boost Converter on Single Phase Full-Bridge Diode

In various industrial applications, the use of a power supply that uses a conventional diode single-phase rectifier topology results in high harmonic values in the electricity distribution system. One of the real impacts of this harmonic value is the heating of the electric power system equipment and power losses. High rms current values due to harmonics often cause problems in protection settings in addition to efficiency problems. The percentage value between the total harmonic component and the fundamental component is called THD (Total Harmonic Distortions). Therefore, in this study an asynchronous dc-dc boost converter is connected to the output side of a single-phase diode rectifier which is capable of improving power factor and low harmonics. So that a THD value of less than 15%, PF (Power Factor) = 0.92-1 and a sinusoidal input current can be obtained. The implementation results show that the PFC (Power Factor Correction) method can work well on single-phase diode rectifiers.

Mixed topology optimization: A self-guided boundary-independent approach for power sources

As the use of electrochemical devices becomes more prevalent, advanced optimization techniques, such as topology optimization, are being employed to improve their performance. Among various electrochemical systems, power sources have an intrinsic best operating point that corresponds to the maximum output power. This study proposes a mixed topology optimization approach to enhance the performance of these systems by a simultaneous modification of electrode structure and the working condition. In contrast to the conventional approaches, the proposed method focuses on enhancement of the maximum power point. Thanks to its self-guidance feature, this technique outperforms conventional topology optimization methods and eliminates the need for a prior decision on the optimization starting point. Therefore, the proposed approach has a significant potential for adapting the material distribution to the best working condition. The proposed approach enables more effective topological optimization and takes the utilization of topology optimization in power sources to the next level.

Three-dimensional plasticity-based topology optimization with smoothed finite element analysis

AbstractThis paper presents a novel plasticity-based formulation for three-dimensional (3D) topology optimization of continuum structures. The proposed formulation addresses the optimization problem by combining mixed rigid-plastic analysis with density-based topology optimization, resulting in a volume minimization approach. Unlike conventional stress-constrained topology optimization methods that rely on linear elastic structural analysis, our developed formulation focuses on enhancing the loading capacity of the designed structures based on the plastic limit theory, leading to more cost-effective designs. To improve computational efficiency, we employ the smoothed finite element technique in our proposed method, enabling the utilization of linear tetrahedral elements for 3D mesh refinement. Moreover, the final formulation of our developed method can be efficiently solved using the advanced primal–dual interior point method, eliminating the need for a separate nonlinear finite element structural analysis. Numerical examples are presented to demonstrate the effectiveness of the proposed approach in offering enhanced design possibilities for continuum structures.