Three-phase Circuit Research Articles

Research on Single-Phase and Three-Phase Compatible Isolated On-Board Charger and Control Technology

This paper presents a single-phase and three-phase compatible isolated on-board charger for electric vehicles. The charger is compatible with the single-phase and three-phase AC voltage input and is composed of two-stage circuits. Based on the three-phase six-switch power factor correction (PFC) circuit, by switching on and off, the front stage is transformed into a cascade topology of a totem-pole PFC circuit and boost circuit. The rear stage is a full-bridge LLC resonant converter. In the single-phase or three-phase working mode, the front-stage control strategy is a double closed-loop control. The current inner loop controller is improved for the three-phase six-switch PFC circuit. The PI controller and repetitive controller are connected in parallel to form the current inner loop compound controller, which can effectively reduce the total harmonic distortion of the input current. By using simulation software MATLAB/Simulink, the circuit model was built. The simulation results verify the correctness of the theoretical analysis.

An improved parallel five-level reinjection CSC for self-commutation of thyristor converter

PurposeThis paper aims to study a multi-level reinjection current source converter (MLR-CSC) that adds attracting properties such as the self-commutation and pulse multiplication to the thyristor converter, which is of great significance for increasing the device capacity and reducing current harmonics on the grid side. Particularly, designing advantageous driving methods of the reinjection circuit is a critical issue that impacts the harmonic reduction and operation reliability of the MLR-CSC.Design/methodology/approachTo deal with the mentioned issue, this paper takes the five-level reinjection current source converter (FLR-CSC), which is a type of the MLR-CSC, as the research object. Then, a method that can fully use combinations of five-level reinjection switching functions based on the concept of decomposition and recombination is proposed. It is worthy to mention that the proposed method can be easily extended to other multi-level reinjection circuits. Moreover, the working principle of the three-phase bridge circuit based on semi-controlled thyristors in the FLR-CSC that can achieve the four-quadrant power conversion is analyzed in detail.FindingsFinally, the simulation and experimental results of FLR-CSC verify the effectiveness of the proposed reinjection circuit driving method and the operating principle of four-quadrant power conversion in this paper.Originality/valueThe outstanding features of the proposed driving method for FLR-CSC in this paper include combinations of reinjection switching functions that are fully exploited through three simple steps and can be conveniently extended to other multi-level reinjection circuits.

The analysis of three level inverter circuit with regard to current harmonic distortion by using ANFIS

The inverters are frequently used in power electronics applications in the industrial area. Research on multi-level inverter circuit designs in power systems interfaces has intensified in recent years. The design type and quality of the inverter circuit topology is very important for the output voltage to be closer to the sinusoidal waveform. In addition, artificial intelligence techniques for the control algorithms of the power switches of the inverter circuit provide useful information in terms of monitoring the estimated the voltage conditions of the inverter output parameters. In this work, an Adaptive-Network Based Fuzzy Inference Systems (ANFIS) model is proposed to estimate the Total Harmonic Distortion (THD) value of the output current of a three-phase three-level inverter circuit. By changing the switching frequency in the control circuit of the inverter, a data set for the THD values of the inverter current is obtained by Fast Fourier Transform (FFT) analysis in MATLAB. This data set is used in a training and testing phase of ANFIS artificial intelligence algorithm, and the THD value of the current is estimated. At the end of the estimation, the mean absolute error (MAE) values for training and testing are obtained as 0.1894% and 0.4009%, respectively, thereby, an ANFIS estimation example for parametric data set analysis in a power electronics circuit run with Matlab-Simulink software, and a parametric simulation study is presented to the literature for power electronics circuit designers.

Development of a low-cost IoT system based on LoRaWAN for monitoring variables related to electrical energy consumption in low voltage networks

Energy efficiency is an issue that is currently gaining relevance, high electricity demands worldwide generate a negative impact on the planet caused by the natural depletion of resources associated with production processes. In this regard, the technologies associated with the Internet of Things (IoT) are considered as a tool to optimize processes and resources through the monitoring of variables. In this context, this work proposes a low-cost electronic system with IoT architecture used in the monitoring of electrical variables, this becomes a support tool in the estimation of energy consumption in internal distribution electrical circuits of homes or small industries. This device generates information to recognize consumption patterns and load balances per electrical phase, contains two hardware modules and a software user interface. The first is an electronic node that includes a high-performance polyphase meter based on the Atmel M90E32AS chip, which is controlled by an ESP32 chip, for wireless communication is used a Radio Frequency (RF) module in the 915 MHz band and LoRa protocol based on the Semtech SX1278 transceiver, this node is able to measure and transmit variables such as current, voltage, active energy, reactive energy, power factor and other electrical variables in circuits of up to three phases. For the study, a calibration process was carried out in an accredited laboratory (Metrex S.A. in Colombia), then tests were performed by monitoring a three-phase 110V electrical circuit in a small factory, with the information generated it was possible to identify consumption patterns over a period of seven consecutive days, important data such as times when energy is wasted due to improper use of loads connected to the network, electric stoves, computer equipment turned on during non-working hours are examples of the results obtained.

Unsynchronized Measurements Based Fault Location Algorithm for Active Distribution Systems Without Requiring Source Impedances

This paper introduces a fault location algorithm, which is appropriate for unbalanced power distribution systems with distributed generation of any type (i.e., synchronous machines and inverter-based units). The proposed algorithm is based on three-phase circuit analysis and utilizes unsynchronized voltage and current measurements taken from the connection points of the sources. The source impedances are not required to be included in the bus impedance matrix formulation. The algorithm accurately estimates the fault position, the fault resistance and the synchronization angles. Moreover, the algorithm can successfully identify the most possible fault location candidate among multiple choices. Extensive simulation studies demonstrate a very good performance of the proposed fault location algorithm for any fault type under various parameters that may influence its accuracy.

Method of Cylindrical Linear Induction Motor Equivalent Circuit Parameters Determination and Performance Calculation Algorithm

Cylindrical linear induction motors (LIM) are currently used in many industrial applications. Task of modeling of electrical machine is of great importance for optimization of processes of design and manufacture of engines with optimal technical characteristics. Traditional approach of construction of mathematical models of asynchronous machines based on classical theory of electrical machines, in comparison with methods of field theory and numerical methods, is much simpler. Structurally cylindrical LIM are distinguished by the absence of transverse edge effects, which contributes to the use of the methods of the classical theory of electrical machines for construction of their mathematical models. In this paper proposes an analytical method of calculation of parameters of equivalent circuit and operating characteristics of cylindrical LIM. In work engine was studied, movable part of which is made in the form of solid steel bar with a copper coating. Equivalent circuits of linear induction motors of various designs (one-sided, two-sided, cruciform, cylindrical) are considered, and assessment of the possibility of their application for research motor is made. Work of cylindrical LIM on industrial mechanisms is characterized by relatively small value of working stroke. For such engines, it is difficult to carry out standard tests, in particular idle stroke test, in order to obtain data for calculation of parameters of the equivalent circuit. The paper proposes a method of experimental determination of parameters of the equivalent circuit. Stator active resistance is measured at direct current, and stator reactance is measured using out-of-rotor method. The remaining parameters of equivalent circuit are calculated according to short circuit experience and engine work mode without load (is taken as an idle stroke experience). It is shown that exact G-shaped equivalent circuit, when calculation of parameters of which active and reactive components of correction factor and active resistance of magnetization branch are taken into account, provides acceptable accuracy in determination of values of equivalent circuit parameters. Algorithm of calculation of work characteristics of cylindrical LAM based on equivalent circuit data is presented. Comparison of calculated and experimental data showed satisfactory results, error is not more than 7%. A new model for decomposition of the total power losses, which includes four components is proposed. Each of the components of the proposed model has a certain physical meaning due to the nature of electromagnetic processes in a three-phase four-wire system. Definitions to describe each of the proposed components are formulated. It is shown that each of supplementary components of the total loss power is proportional to the minimum possible loss power and to the square of the RMS value of the power, which is caused by its occurrence in three-phase four-wire power supply system, and it is inversely proportional to the mean square of the net power loss. The synthesized Matlab-model for verification of the four-component structure of power losses showed a high degree of its adequacy. The proposed model allows us to rethink the description of power losses in three-phase AC circuits and can be used in specialized measuring instruments for electrical networks monitoring. Using the information obtained in the monitoring process, it is possible to plan technical measures to reduce losses of electrical energy in the power supply system, as well as to estimate the capital costs of these measures.

DPC of Cross-compensated Virtual Flux Double Switch Table

Aiming at the problems of large power ripple, high harmonic components and DC bias on the AC side of the three-phase voltage rectifier Direct Power Control (DPC), as well as the shortcomings of the voltage output of the DC side busbar, the direct power control method of the cross-compensated virtual flux double switch meter has been proposed. The virtual flux can realize the sensorless mode on the input side of the circuit to reduce the high harmonic, even if the first-order low-pass filter is used to replace the integration region, there is still some error. On this basis, the two filters are connected in parallel for virtual flux compensation, and then the voltage vector is selected according to the instantaneous power change, and the sector is re-divided with the voltage as the control vector, and two independent switching state tables are designed. The cross-compensated virtual flux double-switch meter DPC is simulated and compared with the traditional DPC waveform, and the experimental results show that the cross-compensated virtual flux double-switch meter DPC strategy can effectively reduce the proportion of harmonic content, control power fluctuations, improve DC bias, has fast tracking effect, stabilize output voltage, and control active and reactive power flexibly. The three-phase voltage rectifier circuit occupies an important position for the pre-rectifier part of the charging power supply of electric vehicles, and the rectifier circuit that can stabilize the output DC voltage cannot only extend its service life for the charging power supply, but also reduce harmonic pollution.

Harmonics Current Detection in Three-phase Circuit using Neural Network

Harmonics seriously affect the safety and economy of power system. In order to control harmonics effectively, harmonic current and harmonic power must be detected quickly. Based on the analysis of the components of three-phase nonlinear current, a neural network detection method of fundamental and harmonic current in three-phase circuit is proposed. The method uses a neural network instead of the low-pass filter in the instantaneous reactive power theory. The example results show that the proposed method has the advantages of less computation, better real-time performance and high detection accuracy. The method can be used to detect the positive-sequence (negative-sequence) fundamental active current, positive-sequence (negative-sequence) fundamental reactive current, harmonic, distortion current and harmonic power.

Design and Implementation of Programmable Logic Controller Based Automatic Transfer Switch

A PLC-based automatic transfer switch (ATS) may improve production in the industry efficiency and also the household power connection. It's an electrical switch that may be used to change the load when the main power is failing to supply electricity. Manually controlled transfer switches exist. In this scenario, a switch must be thrown by an operator to take manual control of the system. Some, on the other hand, are activated automatically when the main power source fails. When a major source of electricity is no longer functioning, power from a new or used generator can be either manually or automatically transferred when utilize a transfer switch for transferring control to the on-side application. Using a programmable logic controller (PLC), we describe the implementation and design of an automatic transfer switch (ATS). The primary function of a transfer switch is to divert electricity from the main grid to a standby power supply. Single-phase and three-phase circuit breakers, Siemens Logo PLC, relays, and indicator lights are used in this system. This portable and economic system would be helpful to every domestic, industrial, factory, and academic institution.

Design and Implementation of Programmable Logic Controller Based Automatic Transfer Switch

A PLC-based automatic transfer switch (ATS) may improve production in the industry efficiency and also the household power connection. It's an electrical switch that may be used to change the load when the main power is failing to supply electricity. Manually controlled transfer switches exist. In this scenario, a switch must be thrown by an operator to take manual control of the system. Some, on the other hand, are activated automatically when the main power source fails. When a major source of electricity is no longer functioning, power from a new or used generator can be either manually or automatically transferred when utilize a transfer switch for transferring control to the on- side application. Using a programmable logic controller (PLC), we describe the implementation and design of an automatic transfer switch (ATS). The primary function of a transfer switch is to divert electricity from the main grid to a standby power supply. Single-phase and three-phase circuit breakers, Siemens Logo PLC, relays, and indicator lights are used in this system. This portable and economic system would be helpful to every domestic, industrial, factory, and academic institution.

A bidirectional three‐phase triple‐voltage LLC (T 2 ‐LLC) resonant converter for DC/DC stage in solid state transformer and DC transformer applications

This paper proposes a novel bidirectional three-phase triple-voltage LLC (T2-LLC) resonant converter, which can be applied as the submodule of DC transformer (DCT) with fixed input and output terminal voltages. A novel series-connected three-phase circuit is adopted at medium voltage (MV) side to improve the voltage level of single submodule (SM) and decrease SM number. Therefore, the power density of DCT can be improved. Besides, the proposed converter is open-loop controlled with fixed switching frequency, and it naturally realizes bidirectional power flow without changing controlling modes according to the power direction. However, the efficiency and voltage conversion ratio of proposed T2-LLC converter are sensitive to resonant parameters, and consistency of three-phase resonant parameters should be ensured to achieve three-phase symmetrical operation. Therefore, design and optimization methods are proposed to realize ZVS turn-on, reduce power losses and ensure fixed voltage conversion ratio. The operation principle and optimization method are presented and a 1000 V/333.3 V/5 kW platform is used to validate feasibility of the proposed converter.

TRANSIENT ANALYSIS IN THREE-PHASE ELECTRICAL CIRCUITS WITH DISTRIBUTED PARAMETERS AND INTERFACIAL CONNECTION ON THE EXAMPLE OF HIGH-VOLTAGE CABLE LINE

The analysis of transients in three-phase electric circuits is carried out, which allowed to consider changes of transient components of currents and voltages of each phase of three-phase cable power line and to estimate the level of overvoltage and amplitude of short-circuit currents in screens taking into account transposition. Using the MatLab/Simulink program, software tools and methods for numerical calculation of transient electromagnetic processes in the designed 330 kV cable line were developed to analyze the level of voltages on the screens and currents in the cable cores at different switching modes. The calculations of a specific 330 kV cable line with a length of 13 km, laid for the first time in Ukraine for the power supply of the electric steel complex, were carried out. The calculation of the emerging transient electromagnetic processes in such a line under different conditions of its connection to the three-phase power supply network is carried out. Many types of switching overvoltages are subject to limitation. Feasibility studies of overvoltage protection measures include assessment of statistical characteristics of damage due to damage, simple or extraordinary repair of electrical equipment of the cable line, as well as due to violation of the technological process by consumers. The above determines the relevance of modeling and analysis of electromagnetic processes that occur when connecting and switching cable lines in ultra-high-voltage three-phase electrical circuits. This allows us to recommend the results of work to develop methods for determining the allowable and emergency modes of similar three-phase cable transmission lines and the choice of rational circuit design solutions in their design. Analyzing the transients in the mode of single-phase short circuit, we can conclude that to select the optimal lengths of the transposition sections of cable screens, it is necessary to consider single-phase short circuit mode, as in this mode there are unacceptable overvoltages on cable screens and currents in three-phase cable lines.

Research on diagnosis method of series arc fault of three-phase load based on SSA-ELM

Arc fault in the three-phase load circuit may cause fire, resulting in production interruption and even worse, it will cause casualties. In order to effectively detect the arc fault in the three-phase circuit, series arc fault experiments of three-phase motor load and frequency converter were carried out under different current conditions. Firstly, variational mode decomposition (VMD) was performed for each cycle of A-phase current, and then the VMD energy entropy and sample entropy were calculated. Secondly, the noise-dominated component was removed according to the permutation entropy, then the average value after first-order difference of the half-cycle reconstructed signal was obtained. An arc fault diagnosis model of extreme learning machine (ELM) optimized by sparrow search algorithm (SSA) was established. The feature vectors were divided into training group and test group to train the model and test its fault diagnosis accuracy. Compared with GA-ELM, PSO-ELM, support vector machine (SVM) and SSA-SVM, the experimental results show that the proposed method can identify the series arc fault accurately and more quickly.

Fractional order PID controlled quasi Z-source inverter with front-line semiconductor material made of power electronics switches fed PMSM motor for EV applications

In the area of control theory, conventional PID controller is most commonly used for various applications to bring out the output of the system at higher efficacy. Now due various technological advancements, PID controller is derived into various advanced controllers. In the advancement of PID controller, there is a controller called Fractional Order PID controller which used widely in industrial applications. The advancement o9f classical integer order PID controller is the FOPID controller. This paper deals with the control of PMSM by FOPID controller. In this work, different control strategies such as Proportional Integral (PI) controller, and Fractional Order Proportional Integral Derivative (FOPID) controller is exploited to sustain the constant yield motor speed of the quasi z-source with 3-phase inverter fed PMSM drive. Also, the source disturbance is introduced to analyze the performance of quasi z-source with 3-phase inverter fed PMSM driven by different controllers. The implementation of FOPID controller will gives out the enhanced response in Quazi Z source inverter fed PMSM. The closed loop system with the FOPID controller has reduced steady state error, improved rise time, settling time and the peak time, when compared with the closed loop system with PI controller. The simulation has been done utilizing MATLAB Simulink software. As discussed, outcomes reveal that the quasi z-source with 3-phase inverter fed PMSM driven by the FOPID-FOPID controller has good-performance such as transient response etc., when compared to the PI-PI controller. Material properties affect the performance and efficiency of power electronic switching devices in three phase inverter circuits. These are generally silicon switches. To increase material technology and performance, switching devices employ wide band-gap semiconductors. This paper also examines the optimal semiconductor material utilized in the three-phase inverter circuit's power electronic switches.

A Decomposition Four-Component Model for Calculating Power Losses in Low-Voltage Power Supply Systems

A new model for decomposition of the total power losses, which includes four components is proposed. Each of the components of the proposed model has a certain physical meaning due to the nature of electromagnetic processes in a three-phase four-wire system. Definitions to describe each of the proposed components are formulated. It is shown that each of supplementary components of the total loss power is proportional to the minimum possible loss power and to the square of the RMS value of the power, which is caused by its occurrence in three-phase four-wire power supply system, and it is inversely proportional to the mean square of the net power loss. The synthesized Matlab-model for verification of the four-component structure of power losses showed a high degree of its adequacy. The proposed model allows us to rethink the description of power losses in three-phase AC circuits and can be used in specialized measuring instruments for electrical networks monitoring. Using the information obtained in the monitoring process, it is possible to plan technical measures to reduce losses of electrical energy in the power supply system, as well as to estimate the capital costs of these measures.

APPLICATION OF SOME MODELS OF POWER SUPPLY SYSTEMS WITH AN EXAMPLE OF TAKING INTO ACCOUNT THEIR RELIABILITY FOR INDUSTRIAL ENTERPRISES IN PRACTICE

The publication presents the most common and promising models and schemes for replacing the power supply system of industrial enterprises, and an example of their use in practice for power supply to sewage treatment plants of a chemical enterprise. Various types of models are considered (in tabular form, in the form of an electrical replacement circuit or in the form of a finite-state machine), as well as a logical-probabilistic approach to the representation of the power supply system. The use of automation systems in power supply systems of industrial enterprises can reduce the total number of accidents, prevent their development, reduce the time of disconnections of electrical installations and downtime of mechanisms, and also allows to transfer to work without constant maintenance a significant number of electrical installations of substations, which, in turn, leads to a reduction in the number of service personnel, increase labor productivity and reduce maintenance costs. One of the main tasks on the way to automating the power supply system of enterprises is to present it in the form of a model. The list of replacement models and schemes that can be used to represent the power supply system of enterprises is quite large, and choosing the appropriate model, for that best meets the requirements of the final goal is quite a complex scientific task. The purpose of this article is to analyze the most common and promising models and schemes for replacing the power supply system and provide recommendations on their application in practice for power supply to sewage treatment plants of a chemical enterprise. Presenting the power supply system in the form of a table allows you to simplify and visually perform certification of electrical equipment, identify problem and weak points in the power supply system of industrial enterprises. Such a table proves that a large amount of electrical equipment at lower levels depends on a single electrical device at higher levels. The representation of the power supply system in the form of a three-phase symmetric replacement circuit can be used to calculate short-circuit currents in symmetric and unbalanced modes in the MatLab program and similar. Using the model of the power supply system in the form of a finite-state machine allows you to visually check the reliability of power supply to consumers, simplify the design of the power supply system of an industrial enterprise, select the state of switching devices in the power supply system and take into account the advantages and disadvantages of each state. It is advisable to use the methods discussed in this article to represent the power supply system (in tabular form, in the form of a finite-state machine or a three-phase symmetric replacement scheme) and their further application and use in automated power supply systems of industrial enterprises. The logical-probabilistic method allows us to consider the issue of power supply reliability based on the theory of logical algebra.

Method for the Analysis of Three-Phase Networks Containing Nonlinear Circuit Elements in View of an Efficient Power Flow Computation

The present paper is devoted to applying the Hănțilă method for solving nonlinear three-phase circuits characterized by different reactance values on the three sequences (positive, negative and zero). Nonlinear elements, which are components of the circuit, are substituted by real voltage or current sources, whose values are an iteratively corrected function of the voltage across or the current through them, respectively. The analysis is carried out in the frequency domain and facilitates an easy evaluation of the power transfer on each harmonic. The paper presents numerical implementations of the method for two case studies. For validation, the results are compared against those obtained using the software LTspice in the time domain. Finally, the power flow on the harmonics and the overall power balance are analyzed.

Analysis of subharmonic oscillations in multi-phase ferroresonance circuits using a mathematical model

The article about solution of system of nonlinear differential equations that are almost impossible to solve by analytical methods by constructing a mathematical model of nonlinear oscillations occurring in three-phase ferroresonance circuits. A system of nonlinear differential equations was formed by approximating the volt-ampere characteristics of a ferromagnetic element in a ferroresonance circuit. Mathematical models for solving technical problems characterizing subharmonic oscillation processes in three-phase ferroresonance circuits and systems using the finite-difference method are expressed in the form of differential equations without appropriate initial conditions. Amathematical model of a system of equations representing subharmonic oscillations in ferroresonance connections depending on the value of the selected parameters in the field of change of any variable is considered.

Multifunctional UPQC operating as an interface converter between hybrid AC-DC microgrids and utility grids

This paper proposes a multifunctional hybrid unified power quality conditioner (UPQC-H), adapted to operate as an interface converter between utility grids and hybrid microgrids (H-MG). In addition to the generation of both ac and dc buses to the H-MGs, the main structure of the UPQC-H can also integrate distributed generation (DG) systems and energy storage systems (ESS) without the need for changing any control strategy. The proposed UPQC-H is built by including two additional power switches to the conventional three-phase UPQC power circuit, which in its traditional configuration is composed of two three-phase inverters used to operate as series and parallel converters. Some advantages related to the proposed UPQC-H configuration can be highlighted, as follows: 1) versatile application to any H-MG configuration; 2) natural power exchange between the H-MG ac and dc buses of both grid-connected and islanded operating modes; 3) seamless transitions between the islanded and grid-connected operating modes, and vice versa; and 4) smoothing of intermittency issues associated to renewable energy sources. Extended static and dynamic experimental results are presented to evaluate the UPQC-H performance and explore its functionalities when interfacing a 3-phase utility grid and an H-MG with integrating photovoltaic-based DG and ESS.

Partial Series Resonance Pulse Commutated Current-Fed Three-Phase Current Sharing DC–DC Converter: ZCS Analysis, Design, and Experimental Results

A three-inductor current-fed converter leveraging short pulse series resonance to facilitate zero-current switching (ZCS) and voltage clamping of the semiconductor devices is proposed and investigated in detail. The circuit exploits series resonance characteristics during conduction overlap of any two switching signals that naturally reduce the current in outgoing switch to zero accomplishing zero-current turn- off . It succeeds in natural switch voltage clamping eliminating the traditional snubber requirement. Owing to the short resonance period, circulating current through the converter limits the conduction losses particularly at light load, thus improving the light-load efficiency. In addition, current-sharing topology offers reduced current stresses through the primary side devices and simpler gate driving requirements because of common source grounded with power supply. Detailed analysis and design are reported. Experimental results from 1-kW proof-of-concept hardware prototype are established to validate the projected claims and confirm the performance and the efficacy of proposed converter. This concept has been verified in single-phase topologies and first time studied for three-phase current-fed circuit.