DC Voltage Source Research Articles

Finite-time tracking control with fast reaching condition for disturbed more electric aircraft direct current microgrid with constant power loads

Future more electric aircraft (MEA) can be seen as a direct current microgrid (DC MG). While DC MG can generally achieve safe, efficient and reliable operation of the system, constant power loads (CPLs), unknown resistive loads, DC source voltage variations, and disturbance inputs might degrade the overall stability and performance if they are not compensated in the control design procedure. In this paper, a fast-reaching condition-based sliding mode control (SMC) is proposed for the DC MG. The fast-reaching law contains two terms that improve the transient performance by forcing the system states to reach a sliding surface with two different rates. This attribute enhances the speed of convergence of the states to the sliding surface compared to conventional SMC. Additionally, the suggested method is resilient to system parameter uncertainties, which is indispensable in practice. The proposed controller is implemented to a DC MG that is supplied by an uncertain DC source and feeds CPLs and resistive load with time-varying power and resistance. OPAL RT results illustrate the robustness and fast convergence of the planned SMC controller.

The Impact and the Need for the DC/DC Converter to Adapt the Energy Produced by the Photovoltaic Generator

Considering the environmental effects and the shortage of fossil fuels, research encourages us towards the development and use of more and more renewable energies such as the autonomous photovoltaic system which is very much used for rural applications such as solar lighting, battery charging, etc. The beginning of our study describes the photovoltaic effect and the current-voltage and power-voltage characteristics of a mathematical model of a cell with a single diode. This allows us to model a solar panel and get an idea of the behavior of the field and the photovoltaic generator. The model predicts the behavior and characteristics of the PV model using the Matlab/Simulink platform. Connected to a basic circuit, the constant DC source voltage step-up converter first and to the PV system last, allows us to conclude that the presence of power electronics is essential in the photovoltaic system in order to adapt and d Ensuring its proper functioning and satisfactory results suggest the effectiveness of this model.

Fault Diagosis of CHB Inverter Using Machine Learning

Renewable energy has gained popularity due to depleting natural resources and escalating fossil fuel and nuclear pollution. Power electronic engineers design grid-connected power conversion systems. MLIs provide more power and solutions. Cascaded H-Bridge (CHB) MLIs start with two or more 3L single-phase H-bridge inverters. Each H-bridge may produce three separate voltage levels. Combining the separated dc voltage sources produces a stepped output voltage with a step size equal to the magnitude of the connected sources. The present work develops a method for detecting and resolving switch failures in a three-phase CHB inverter, ensuring system dependability and allowing for system redundancy. The recommended approach uses Wavelet transform to extract features, then Decision Tree classifier to detect and characterise defects. Increased classification accuracy shows the DT-based fault diagnosis system's efficiency in identifying inverter switch faults.

Harmonic reduction using Particle Swarm Optimization based SHE Modulation Technique in Asymmetrical DC-AC Converter

Many inverters play an important role in transmitting and processing energy to power system networks. To reduce the cost and size of multilevel inverters, various topologies have been included in the literature. But these topologies do not look at the complete harmonic distortion in the output waveform. In this study, a modern multilevel inverter structure, a mutated H-bridge inverter is adopted that demands a small amount of switches, driver circuits, power diodes and DC voltage sources compared to conventional multilevel inverters to produce the required level in the output voltage. The mutated H-bridge converter uses a nearest-level control method, produces high value of total harmonic at the output voltage and low-level harmonics content is also high, which is more dangerous than high-order harmonics. Therefore, the selective harmonic elimination (SHE) method is used to reduce the low frequency harmonics and the total harmonic distortion to the output voltage. Comparison of complete harmonic deviation and low-level harmonic content using the above-mentioned control strategies on the 31-level inverter is presented. Simulation studies confirm the performance of a 31-level inverter with low-order harmonics and a complete harmonic distortion using the SHE process. The effectiveness and accuracy of the SHE in producing 31 level waveform is demonstrated by utilizing the test outcomes and the THD found is of the order of 2.8%, 1.7%, 1.7% and 1% for the modulation index values of 0.5590, 0.7440, and 0.8380 and 0.9110 respectively.

Assessment of harmonic mitigation performance of electric springs with different inverter topologies

Electric spring (ES) is a new technology inspired by the idea of realization a system that is equivalent to mechanical springs in terms of functionality within power systems. Electric springs are comprised from a DC voltage source, an inverter and an LC filter at the grid side. It can be used effectively in power systems to perform many functions such as voltage regulation, reactive power compensation, demand management and energy storage. On the other hand, due to the semiconductor elements in ES structure, it causes distortion on voltage and current waveforms. However, various control approaches have been proposed in the literature in order to prevent the aforementioned distortions. In this study, three different ESs has been modeled with the inverter topologies chosen from the frequently preferred once used in applications, namely Half-Bridge, Full-Bridge, and Neutral Point Clamped Multi-Level Inverter (NPC-MLI). The disruptive effects of electric springs with different inverter topologies on the grid and their performance in harmonic elimination have been examined through the results obtained from simulations realized in MATLAB/Simulink®.

A Multi-Source DC/AC Converter for Integrated Hybrid Energy Storage Systems

Hybrid energy storage systems are developed in various applications to integrate high-energy battery packs and high-power ultracapacitor banks. Multi-source inverters are used for the active control of energy sources in hybrid energy storage systems. Due to the magnetic-less topology of the multi-source inverters, the weight, volume, and power losses of the hybrid energy storage systems are reduced, while keeping similar performance. In this paper, a multi-source inverter is developed for the integration and active control of a high voltage DC source and a low voltage DC source, such as battery packs and ultracapacitor banks in energy storage system applications. The topology of the proposed multi-source inverter has a lower number of switching devices compared with the previously presented counterparts. Moreover, the number of conducting switches is reduced, which results in reduced power losses and improved efficiency. A closed-loop current controller is utilized to validate the proper operation of the proposed multi-source inverter topology. A proper space vector modulation technique is implemented to generate appropriate switching pulses during all operating modes. The performance of the proposed multi-source inverter is verified through simulations on PSIM software and experiments on a laboratory prototype.

Prototipe Sistem Pemantauan Tegangan Drop pada Sel Baterai 110 Vdc berbasis Aplikasi Telegram

Batteries are electrochemical devices as a source of DC voltage that is quite reliable and has high stability, so that the 110 Vdc Battery has a very important role at the substation (GI) to operate the driving motors at the voltage breaker (PMT), disconecting switch (PMS), supply PLC and telecommunication equipment in the SCADA system, as well as protection relays. If the 110 Vdc battery does not work properly, it can result in a major interference with the GI. So to help optimize battery maintenance, it needs an indication tool so that the battery can last a long time and can prevent damage to the battery prematurely. In this study, a voltage drop monitoring and detection system will be designed on 110 Vdc battery cells. The data will be forwarded to the database via the NodeMCU device to be sent to the Telegram application on the smartphone. The test was carried out by compiling 80 battery cells with a voltage of 1.5 volts in series to produce a voltage of 110 Vdc. Test results of the accuracy level of voltage readings achieved an average accuracy of 99.58% with an average difference of 0.42% while the test results of sending voltage data for each group were successfully carried out with excellent response and were able to display data / information on voltage values and conditions in telegram applications.

Energy Consideration of a Capacitor Modelled Using Conformal Fractional-Order Derivative

Fractional order circuit elements have become important parts of electronic circuits to model systems including supercapacitors, filters, and many more. The conformal fractional derivative (CFD), which is a new basic fractional derivative, has been recently used to model supercapacitors successfully. It is essential to know how electronic components behave under excitation with different types of voltage and current sources. A CFD capacitor is not a well-known element and its usage in circuits is barely examined in the literature. In this research, it is examined how to calculate the stored energy of a CFD capacitor with a series resistor supplied from a DC voltage source. The solutions given in this study may be used in circuits where supercapacitors are used.

Performance investigation of modular multilevel inverter topologies for photovoltaic applications with minimal switches

Introduction. In recent years, a growing variety of technical applications have necessitated the employment of more powerful equipment. Power electronics and megawatt power levels are required in far too many medium voltage motor drives and utility applications. It is challenging to incorporate a medium voltage grid with only one power semiconductor that has been extensively modified. As a result, in high power and medium voltage settings, multiple power converter structure has been offered as a solution. A multilevel converter has high power ratings while also allowing for the utilization of renewable energy sources. Renewable energy sources such as photovoltaic, wind, and fuel cells may be readily connected to a multilevel inverter topology for enhanced outcomes. The novelty of the proposed work consists of a novel modular inverter structure for solar applications that uses fewer switches. Purpose. The proposed architecture is to decrease the number of switches and Total Harmonic Distortions. There is no need for passive filters, and the proposed design enhances power quality by creating distortion-free sinusoidal output voltage as the level count grows while also lowering power losses. Methods. The proposed topology is implemented with MATLAB / Simulink, using gating pulses and various pulse width modulation methodologies. Moreover, the proposed model also has been validated and compared to the hardware system. Results. Total harmonic distortion, number of power switches, output voltage and number of DC sources are compared with conventional topologies. Practical value. The proposed topology has been very supportive for implementing photovoltaic based multilevel inverter, which is connected to large demand in grid.

Electromagnetic and Electromechanical Compatibility Improvement of a Multi-Winding Switch Control-Based Induction Motor—Theoretical Description and Mathematical Modeling

The main advantages of multi-winding (multiphase) induction machines include reducing torque ripple, decreasing rotor harmonics losses, reducing the current per phase without increasing the voltage per phase, reducing the current harmonics of the DC voltage source, and high fault tolerance. The authors propose a theoretical description for the harmonic content of the DC-link current, magnetomotive force, and electromagnetic torque of a multi-winding induction machine (IM), and an account of the interaction of the time harmonics for the power supply and the spatial harmonics for winding functions is presented. The proposed theoretical analysis has made it possible to substantiate supply-winding schemes for the compensation of higher harmonics (6th and 12th in the DC-link current and the IM’s electromagnetic torque) and the improvement of the electromagnetic and electromechanical compatibility of the multi-winding machine, which are justified according to the proposed theoretical description. Further, a schematic solution for the multi-winding induction motor with electronic changing of the pole number is proposed to provide a reduction in speed ripples at low rotation speeds. This decrease is ensured by increasing the number of pole pairs and increasing the frequency of the supply voltage. Mathematical models of multi-winding switch control-based induction machines are developed using the method of average voltages in the integration step for an investigation of electromagnetic and electromechanical processes. It is shown that the developed models are distinguished by high speed of response and accuracy. This is confirmed by the comparative analysis using known methods and models in the Matlab environment, as well as a comparison of the simulation results with the known results of physical experiments. The results of mathematical modeling show that the use of a multi-winding IM with appropriate supply-winding schemes stands to significantly reduce the ripples of the IM’s electromagnetic torque and DC-link current in the case of using six-step voltage source inverters. This makes this type of inverter suitable for use in a frequency-controlled electric drive as an alternative to using a PWM inverter, which has a negative influence on the IM’s state.

Single source self‐balanced switched‐capacitor multilevel inverter with reduced number of semiconductors

Recently, the demand for switched-capacitor converters has increased due to the use of a low voltage input source. This article aims to improve some weak points of these inverters, such as the high number of elements by presenting a novel single-source high step-up multi-level inverter topology. The proposed inverter consists of a switched-capacitor cell with self-balancing capability. The proposed converter uses a low voltage DC source to charge a series of capacitors stage by stage to increase the amplitude of the capacitors multiple times the input voltage. These capacitors which work as asymmetrical sources can generate a high-amplitude AC output voltage level and hence reduce the number of DC sources and semiconductors which leads to the simplicity of structure. Since the proposed converter is using low voltage single DC source it can be used in a renewable energy application. Another aspect of this converter is producing negative levels in the output voltage without using a high-voltage full-bridge inverter and reducing the number of components. To verify the proposed multi-level inverter operation, a 9-level prototype is simulated in MATLAB/Simulink and implemented in the laboratory. The simulation and test result of the inverter confirm the validity of the proposed scheme.

Selective harmonic elimination pulse width modulation based hybrid multilevel inverter topology with reduced components

AbstractIn this paper, a reduced switch count single‐phase hybrid multilevel inverter (MLI) is presented. Level generation unit (LGU) and polarity changing unit (PCU) are the two parts of the presented topology which are connected in series. Other advantages of the proposed topology include the reduced switch count, higher level generation with reduced sources and the possibility of higher‐level generation with lower component counts. A single unit produces an output voltage of 13 levels with the modulation techniques as selective harmonic elimination pulse width modulation (SHEPWM) to improve harmonics. The use of selective harmonic elimination (SHM) is made to improve harmonics. The logical generation unit carries a series connection of multiple switched dc voltage sources with half and full‐bridge configurations. The proposed topology is verified by a hardware bench setup as well as in simulations which are developed in Simulink/MATLAB® environment.

Analysis and Development of 53-Level Asymmetric Multilevel Inverter with Reduced Component for Fixed and Variable Loads

An asymmetric multilevel inverter with reduced number of devices is proposed for renewable energy applications. Proposed inverter consists of a basic section and an H-bridge circuit. The basic section is capable of generating three voltage levels (two non-zero and one zero voltage levels). In order to maximize the number of voltage levels across the load, three frameworks are identified to fix the magnitude of the DC voltage sources used in the circuit. Among the three frameworks, best framework is chosen for the present work and 53-voltage levels are obtained across the load when connecting three proposed basic sections in series with an H-bridge. Furthermore, the proposed circuit is simulated and tested in real time for the fixed and variable reactive loads. Edge control method is used for the circuit and the results are obtained satisfactorily. Due to the reduction in number of switches and number of “ON” state switches the inverter operating efficiency is achieved as 95.56%.

An improved switched diode multilevel inverter topology with fewer on state switches

A double capacitor double diode double switch (DCDDDS) multilevel inverter is proposed in this paper to generate positive voltage and connect a polarity changing circuit of H-bridge inverter that generates negative voltage. The desired level is achieved by connecting the j th number of basic units in series. To generate more stepped levels with fewer switches, various algorithms, such as Natural, Binary, Trinary, and Quasi-Linear sequences, and two new proposed algorithms are discussed to determine the magnitude of DC voltage sources. The proposed multilevel inverter eliminates the need to turn on more power switches for different levels, which is the highlight of this topology. The proposed multilevel inverter is compared in terms of the switch count, number of ON state switches per level, driver circuits, and total standing voltage with the conventional switched diode multilevel inverters. Real-time results from the test bench of OPAL-RT and simulation have been used to validate the proposed inverter.

Coupling electromagnetic numerical models of HTS coils to electrical circuits: multi-scale and homogeneous methodologies using the T-A formulation

Numerical simulation is an effective tool for predicting the electromagnetic behavior of superconductors. Recently, a finite element method-based model coupling the T-A formulation with an electrical circuit has been proposed: the model presents the superconducting constituent as a global voltage parameter in the electrical circuit. This allows assessing the overall behavior of complex high-temperature superconductor (HTS) systems involving multiple power items, while keeping a high degree of precision on the presentation of local effects. In this work, the applicability of this model has been extended to large-scale HTS applications with hundreds or thousands of tapes by referring to two widely recognized methodologies, multi-scale and homogenization, to improve the computation efficiency. Based on the two approaches, three different models were developed and their effectiveness was assessed using the case study of a 1000 turn cylindrical HTS coil charged by a DC voltage source. The comparison of the calculated global circuit parameters, local field distributions, losses, and computation time proves that the computation efficiency can be improved with respect to a model simulating all HTS tapes, without compromising accuracy. The results indicate that the developed models can therefore be efficient tools to design and optimize large-scale HTS devices used in electrical machines and power grids. It is also found that the inductance of an HTS coil is varied according to the transport current and can be even higher than that of a normal conductor coil with the same geometry. We attribute this result to the superconductor’s non-uniform current distribution and relaxation effect during the dynamic process.

A Single-Phase Switching Diode Cascade Multistandard Inverter Based on H-Bridge

Cascaded multistandard inverter is needed in traditional high-voltage occasions, but a large number of electricitys switching devices in cascaded topology make its control complex and can lead to reduced efficiency and increased cost of inverter operation. In my text, a new basic switching diode topology proposed. It contains three switching devices, three electricity diode elements, and three DC voltage source devices with a voltage ratio of 1:1:2. In the way, five correct voltage standards can be output can be generated. Based on the combination of H-bridge topology, a new cascade topology is proposed. They increase the number of voltage standards and can work in asymmetric DC electricity supply. Therefore, different DC voltage source amplitudes can be provided, thereby reducing the number of electrical and electronic components. Compared with other most advanced cascaded topologies, The main advantage of the proposed cascade topology is the reduction where the number of electricity switche, is determined by a reasonable number of DC voltage source and the reduction in cost. At the same time, the rationality and working principle of the proposed topology are discussed, and the corresponding carrier cascade modulation method is proposed. By comparing the export voltage wave with the target waveform, the driving signal of the switch is obtained from the PWM pulse signal. The correctness and feasibility of the topology are verified by matlab2018 / Simulink simulation.

A Novel 17-Level Reduced Component Single DC Switched-Capacitor-Based Inverter With Reduced Input Spike Current

Multilevel inverters (MLIs) have become common and resourceful as a result of the fast advancement of technology in the areas of high-voltage and high-power applications, among other things. Recently, MLIs have received a great deal of attention recently, due to the growing need to harness environmentally friendly energy. With reduced power electronics switches, diodes, and a voltage boost gain factor of 8, this article presents a single-phase 17-level switching capacitor inverter design. The proposed inverter uses single dc voltage source, two diodes, 14 power electronics switches, and three capacitors. The different mode of operation of topology is explained in detail, including their self-voltage balancing technique. Additionally, an inductor is used in the capacitor charging loop to avoid current spikes caused by the input dc source while charging the capacitor quickly, thereby increasing capacitor life expectancy significantly. Compared to previously the proposed single-input MLIs, the proposed inverter has a lower semiconductor switch count and a lower cost function value that are its distinguished feature. The performance of the topology is verified by MATLAB/Simulink, and furthermore, a laboratory prototype is utilized, which confirms the feasibility of the proposed topology.

Effect of Voltage Source Differences on Hydrogen Gas Production by Electrolysis-photocatalysis Reactor Systems

We have evaluated the process of watersplitting into hydrogen gas. Electrolysis-photocatalysis reactor is used to harvest hydrogen gas through water splitting, a combination of electrolysis and photocatalysis reactions. The concentration of hydrogen gas (H2) is detected by the MQ-8 sensor and the number of bubbles is calculated. Evaluation of watersplitting is done by varying the DC voltage source (3V, 6V, 9V, 12V). We found the highest concentration of H2 gas was produced at 12 volts 616300 ppm for 600 seconds, The largest increase from the photocatalyst-electrolysis reaction combination was found to be 182017 ppm. Here we observe a linear increase in hydrogen with increasing voltage which results in a faster electrolysis process. But what is most interesting is the increase in H2 during the simultaneous electrolysis-photocatalysis process. the combined reaction has increased the amount of hydrogen greater than the sum of the photocatalytic and electrolysis reactions taking place separately. It is most likely that a mutually reinforcing reaction occurs so that the overall activation energy of the system becomes smaller in the process of dissociating water into hydrogen.

Research on a Novel Nanosecond Marx Generator and Its Efficiency Analysis

The traditional Marx generators based on avalanche BJTs usually use a DC voltage source to charge the storage capacitors, and many theoretical studies have proved that the existence of DC voltage source leads to low energy efficiency. This paper proposes a novel nanosecond Marx generator based on avalanche BJTs, which is charged by a series-resonant power supply. This power supply charges all capacitors with a constant average current and all BJTs avalanche breakdown stage by stage without any triggering signals. When the resistors are replaced by inductors, the efficiency can be further improved. The pulse repetition frequency can be adjusted by controlling the resonant average current. The output voltage can be increased by connecting more avalanche BJTs in series or increasing the number of stages of the Marx generators. The control method and the structure of the circuit are simple. Experimental results show that negative pulses with an adjustable frequency of 10–60 kHz, a pulse width of 8.45 ns, and an amplitude of 4 kV were obtained on a resistive load. The energy efficiency of the Marx generator was increased to 94%.

A High Gain Two-Winding Switched Coupled-Inductor Network

Summary. This paper proposes a new high-gain quasi-Z-source network (qZSN) with a switched-coupled-inductor (SCL). By employing a two-winding SCL within the impedance network, the proposed topology offers high voltage gains with relatively low shoot-through current and low total voltage stress on switching devices. Other prominent features of the proposed topology can be mentioned as low total voltage stress on the switching devices, continuous dc-input current, and common ground among the input dc-voltage source and the load-side. In addition, the proposed qZSN has a low peak magnetizing current which allows using a smaller size magnetic core for the coupled-inductor. Reduced passive components count along with lower switch current stress lead to lower power losses and converter costs. The superiority of the proposed impedance network is confirmed by comparing its main properties with other successful existing ZS-based topologies. The detailed theoretical analysis and performance principles of the proposed qZSN are validated through experimental results.