3-phase 4-wire Research Articles

Compensation of Budeanu’s Reactive and Complemented Reactive Currents in Extended Budeanu Theory in 3-Phase 4-Wire Systems Powered by Symmetrical Nonsinusoidal Voltage Source

The result of continuous efforts in the development of power theory, Budeanu’s power theory was successfully extended. The mathematical description that has been proposed is based on another concept, namely the Currents’ Physical Components (CPC) theory. With CPC theory, it was possible to describe, in the original Budeanu theory, the components of the load current, including the Budeanu distortion current. The Budeanu distortion current can have a maximum of five components associated with different physical phenomena and related to the equivalent parameters of the load. This article discusses passive compensation, which provides compensation for the Budeanu reactive current and the Budeanu complemented reactive current due to the known equivalent load parameters associated with the reactance elements. In addition, the article refers to a very important aspect when determining the parameters of a passive compensator, i.e., choosing parameters in such a way that the compensator simultaneously compensates for the reactive current and the unbalanced current. The article presents five methods relating to the determination of compensator parameters. Two methods are related to the reactive current compensation only for the first harmonic without affecting the unbalanced current. The next three methods relate to the compensation of the Budeanu reactive current and the consideration of the unbalanced current. Calculations and simulations were performed for all five methods, the results of which are presented and analyzed in this publication. The Matlab/Simulink R2023a environment was used as the calculation and simulation software.

Enhanced Control Strategy Based on Virtual Impedance Loops to Achieve the Sharing of Imbalance and Harmonic in 3-Phase 4-Wire Isolated Microgrids

An improved distributed control strategy for imbalance and harmonic sharing in 4-leg droop controlled power converters for 3-phase 4-wire isolated Microgrids is presented in this letter. The proposed control scheme improves a previous one proposed by some of the authors of this letter in the sense that both negative and zero current sequence components are independently controlled. A numerical comparison between the previous method [1] and the presented in this letter shows that, for the studied case, the negative sequence powers shared among the 4-leg converters using the method [1] are: 1638 VA, 2309 VA, 1760 VA, 2610 VA and 1344 VA (these powers are unequally shared). In contrast, with the improved method, all of these powers are equally shared at 1945VA, showing the effectiveness of the proposal. Similar behaviour was verified for zero-sequence powers, which, for the method [1], varied from 1588 VA to 2547 VA, while the proposed approach produced equal sharing of zero-sequence powers (2072 VA) among all the converters.

EPLL Control Technique Optimum Controller Gains to Control Voltage and Frequency in Standalone Wind Energy Conversion System

This study describes how to regulate the frequency and terminal voltage of a freestanding wind energy conversion system using an Enhanced Phase Locked Loop (EPLL)-based strategy to supply power to varied loads regardless of wind speed. In a standalone wind turbine energy conversion system, the EPLL control scheme extracts the reference source currents (SWECS). The control algorithm employs two proportional-integral (PI) controllers to create the active and reactive power components of the consumers' load currents, estimate reference source currents, and connect the zigzag transformer to PCC with VSC for neutral current compensation. To obtain optimal PI controller gains and most-suited settings to apply to SWECS, optimization approaches are used. The control algorithm is the most significant aspect of the system, and the speed with which it calculates, evaluates, and guesstimates determines the generation of source currents based on the algorithm's ideal controller PI gains. By properly estimating source currents, the EPLL control method improves dynamics and power quality issues, and the optimization technique is employed to acquire the gains of PI controllers. The proposed system employs the EPLL algorithm on a three-phase, four-wire system with changing loads to achieve ideal total harmonic distortion of source currents and voltages on the PCC, as defined by IEEE-519 standards. A battery energy storage device coupled to the VSC dc link keeps the load's necessary power constant. If the generator output exceeds the consumer demand, the excess power is delivered to BESS for temporary storage. When consumer demand exceeds generated power, a BESS delivers deficit power to the load, which adjusts and the frequency under various load conditions. The suggested system simulated results were tested with 3-phase 4-wire for harmonics reduction, load balancing, neutral wire current compensation, frequency and voltage control using MATLAB / Simulink.

Tuning of state-feedback multi-resonant controllers based on LQR using differential evolution metaheuristic

This paper proposes a generic methodology for tuning state-feedback multi-resonant (SF-MR) controllers in power electronics applications involving L, LC, and LCL filters. The tuning of the controllers is performed using differential evolution metaheuristic in conjunction with the well-known linear-quadratic regulator (LQR) approach. This optimization algorithm avoids the empirical trial-and-error method for adjusting the weighting values of Q and R matrices while minimizing the cost function based on a weighted sum of the total harmonic distortion of the controlled variables, control loop errors, and control signals saturation. Thus, an adequate approach to adjust LQR-SF-MR controllers is achieved, proving useful for controlling active power filters (APF) since non-sinusoidal control references are involved. Furthermore, the proposed tuning method is appropriate for controlling voltage source inverters (VSI) following sinusoidal references and feeding non-linear loads since the high rejection of harmonic disturbances is reached. The effectiveness of the proposed design methodology for controllers' tuning is tested in a current-controlled 3-phase 4-wire (3P4W) shunt-APF, grid-connected through both L and LCL filters, as well as in a voltage-controlled 3P4W VSI connected to non-linear loads with LC filters. The control performances of the systems are extensively evaluated through experimental results.

Output Voltage Imbalance Compensation Using dc Offset Voltage for Split dc-Link Capacitor 3-Leg Inverter

In this paper, we analyzed the output voltage imbalance and the cause of the offset voltage in 3-phase 3-leg inverters by using Millman’s theory. Based on this result, we proposed a voltage imbalance compensation algorithm using the dc offset voltage that appeared at the neutral point voltage of the load. To apply the proposed imbalance compensation algorithm, it needs a circuit structure of 3-phase 4-wire such as split dc-link capacitor 3-leg inverter and 4-leg inverter. Therefore, the total harmonic distortion (THD) of the load phase current according to the imbalance rate of the load was analyzed for the two inverters. Then, PSIM simulation and experiments based on a 10 kW-prototype of split dc-link capacitor 3-leg inverter were implemented to verify the validity of the proposed imbalance compensation algorithm.

Mitigation of Harmonics by Using Shunt Hybrid Active Power Filter in 3-Phase 4-Wire System

Mitigation of Harmonics by Using Shunt Hybrid Active Power Filter in 3-Phase 4-Wire System

Real Time Harmonic Mitigation Using Fuzzy Based Highly Reliable Three Dual-Buck Full-Bridge APF for Dynamic Unbalanced Load

Abstract This study presents a highly reliable 3-phase 4-wire, three dual-buck full-bridge shunt active power filter (3 DB FB APF) for distribution system. The proposed topology uses three single phase dual buck full bridge inverter sharing the same dc-link capacitor with high utilization of dc-bus voltage. The dual buck inverter circuit composed of one power switch and one diode leg instead of two power switches conventional inverter leg effectually eliminate the undesirable “shoot-through” phenomenon occurs in conventional inverter circuit. The fuzzy and adaptive hysteresis current controller based id-iq control strategy has been adopted to generate optimized switching frequency. For validation, the proposed topology is implemented in the OPAL-RT LAB using OP5142-Spartan 3 FPGA. The dynamic performance of the proposed 3 DB FB APF is assessed for sinusoidal, unbalanced and non-sinusoidal voltage source condition with unbalanced non-linear load that is when both three-phase and single-phase loads are present in the system. Besides, the results with proportional-integral (PI) controller are compared with FLC in terms of harmonic compensation. Furthermore, a comparison has been made between split capacitor dual buck half bridge active power filter (2C DB HB APF) and proposed 3 DB FB APF based on switch power rating.

Design and Control of Autonomous Wind–Solar System With DFIG Feeding 3-Phase 4-Wire Loads

This paper presents the design, control, and experimental investigation of an autonomous wind–solar hybrid energy system feeding 3-phase 4-wire loads. The wind energy block consisting of a double fed induction generator (DFIG) is equipped with maximum power point tracking (MPPT) algorithm. The control of DFIG consists of two converters, namely rotor side converter (RSC) and load side converter (LSC) connected back to back at dc link. The MPPT operation requires speed control, which is realized using field oriented control through RSC. The rotor position required for vector control is estimated with model reference and adaptive system algorithm. The voltage and frequency control is realized through LSC. The solar photovoltaic (PV) power is extracted using a dc–dc boost converter to the common dc link. The dc–dc converter is also equipped with MPPT algorithm to extract maximum power from the incident irradiance. The system is modeled in MATLAB and its performance is presented at conditions, e.g., unbalanced nonlinear load, varying wind speeds, and solar irradiation. Under all these conditions, currents flowing through stator windings of DFIG are balanced with low total harmonics distortion (THD). The THDs of load voltages under all operating conditions are also within requirement of IEEE 519 standard. Finally, simulated results are validated experimentally by developing a prototype of the system using a 5-kW solar array simulator and a 3.7-kW DFIG.

PSCAD를 이용한 3상 유도형 전력량계의 오결선 해석

In order to charge the correctly electric price for power supplied by the electric power producer and the suppliers to the consumer, the electric power consumption must be measured more accurately. However, legal disputes cases between suppliers and consumers are often occurred due to incorrect electric charge problem by the PT or CT incorrect connection of a three-phase four-wire induction watt-hour meter. Therefore, in order to analyze the instrumentation characteristics of watt-hour meter due to incorrect wire connection of a three-phase four-wire induction watt-hour meter, this paper performed modeling for inductive watt-hour meter by using PSCAD / EMTDC. Then, a power measurement test was performed on incorrect connection of induction watt-hour meter by using actual 3phase 4wire induction watt-hour meter and load. Furthermore the modeling results of PSCAD / EMTDC are compared with theoretical values and measured data of incorrect connection induction watt-hour meter, and it is confirmed that the proposed modeling method is a useful tool for evaluation of incorrect connection characteristics of induction watt-hour meter.

ORTHOGONAL COMPONENTS OF THE THREE-PHASE CURRENT AT ASYMMETRICAL ACTIVE - REACTIVE LOAD IN 4-WIRE CIRCUIT

Purpose . For the unbalanced sinusoidal mode with asymmetric voltage in 3-phase 4-wire circuits to receive the orthogonal 4-component decomposition of 3-phase current, are classified symmetry/asymmetry of active and reactive load elements separately. Methodology . The methodology is based on the vector approach, which with one voice allows to analyze the energy characteristics of a 4-wire and 3-wire circuits as balanced and unbalanced modes. At asymmetrical voltage the matrix representation methodology of the equivalent conductivities is used. Results. For 3-phase 4-wire network with a sinusoidal unbalanced mode with asymmetric voltage obtained 4-component orthogonal decomposition of the 3-phase current. The components have a clear electro-energetic sense and are classified irrespective by the load condition. Originality . The resulting decomposition current develops the theory Currents' Physical Components (CPC) for 4-wire circuit with asymmetric voltage. For the first time the unbalanced current is classified by activity and reactivity of asymmetry load elements. Practical value. Practical value of the obtained orthogonal decomposition current and the power equation is a possibility of their utilization for the increase both quality of delivery and quality of consumption of electrical energy.

PI and Fuzzy-Controlled 3-Phase 4-Wire Interleaved Buck Active Power Filter with Shoot-Through Elimination for Power Quality Improvement using RTDS Hardware

Abstract In this paper, shoot-through current elimination DC–AC converter circuit has been presented with the application of active power filter (APF). The intuitive analysis of the shoot-through in the conventional DC–AC converter has been reported first. Interleaved buck (IB) converter is adopted to eliminate the shoot-through current, thereby increasing the reliability of the interleaved buck–based active power filter (IB-APF). The 3-phase 4-wire IB-APF eliminates the current harmonics produced by the load just as a conventional one does and are innately immune to “shoot-through” phenomenon, with the elimination of special protection features required in conventional inverter circuits. A comparison has been made about the compensation capabilities of the IB-APF with the PI and fuzzy logic controller (FLC) used by id–iq control strategy under different supply voltage conditions. The id–iq control strategy used for extracting the three-phase reference current for IB-APF, evaluating their performance here in MATLAB/Simulink environment and also implemented using real-time digital simulator hardware (OPAL-RT hardware). The RTDS result verifies that the total harmonic distortion percentage of the source current can be reduced below 5% according to IEEE-519 standard recommendations on harmonic limits.

PI and Fuzzy Logic Controller Based 3-Phase 4-Wire Shunt Active Filters for the Mitigation of Current Harmonics with the Id-IqControl Strategy

Commencing with incandescent light bulbs, every load today creates harmonics. Unfortunately, these loads vary with respect to their amount of harmonic content and their response to problems caused by harmonics. The prevalent difficulties with harmonics are voltage and current waveform distortions. In addition, Electronic equipment like computers, battery chargers, electronic ballasts, variable frequency drives, and switching mode power supplies generate perilous amounts of harmonics. Issues related to harmonics are of a greater concern to engineers and building designers because they do more than just distort voltage waveforms, they can overheat the building wiring, cause nuisance tripping, overheat transformer units, and cause random end-user equipment failures. Thus power quality is becoming more and more serious with each passing day. As a result, active power filters (APFs) have gained a lot of attention due to their excellent harmonic compensation. However, the performance of the active filters seems to have contradictions with different control techniques. The main objective of this paper is to analyze shunt active filters with fuzzy and pi controllers. To carry out this analysis, active and reactive current methods (<TEX>$i_d-i_q$</TEX>) are considered. Extensive simulations were carried out. The simulations were performed under balance, unbalanced and non sinusoidal conditions. The results validate the dynamic behavior of fuzzy logic controllers over PI controllers.

Fuzzy Controller Based 3Phase 4Wire Shunt Active Filter for Mitigation of Current Harmonics with Combined p-q and Id-Iq Control Strategies

As more and more variable frequency drives (VFDs), electronic ballasts, battery chargers, and static Var compensators are installed in facilities, the problems related to harmonics are expected to get worse. As a result Active power filter (APF) gains much more attention due to excellent harmonic compensation. But still the performance of the active filter seems to be in contradictions with different control strategies. This paper presents detailed analysis to compare and elevate the performance of two control strategies for ex-tracting reference currents of shunt active filters under balanced, un-balanced and non-sinusoidal conditions by using Fuzzy controller. The well known methods, instantaneous real active and reactive power method (p-q) and active and reactive current method (id-iq) are two control methods which are extensively used in active filters. Extensive Simulations are carried out with fuzzy controller for both p-q and Id-Iq methods for different voltage conditions and adequate results were presented. Simulation results validate the superior per-formance of active and reactive current control strategy (id-iq) with fuzzy controller over active and reactive power control strategy (p-q) with fuzzy controller.

Comparative Study of Neuro Controller &amp; Wavelet Transform for Shunt Active Filter in Reducing THD of a 3-Phase 4-Wire System

Comparative Study of Neuro Controller &amp; Wavelet Transform for Shunt Active Filter in Reducing THD of a 3-Phase 4-Wire System

3 Dimensional hysteresis PWM techniques for 3-Phase 4-Wire SAPFs under unbalanced conditions by using p-q-r theory

3 Dimensional hysteresis PWM techniques for 3-Phase 4-Wire SAPFs under unbalanced conditions by using p-q-r theory

Decoupled control of a four-leg inverter via a new 4/spl times/4 transformation matrix

Four-leg (3-phase 4-wire) inverters are developed to power unbalanced/nonlinear three-phase loads. A unique 4/spl times/4 decoupling transformation matrix is used that enables direct transformation between the four degree-of-freedom (DOF) leg-modulation space of the inverter and its corresponding 3-DOF output-voltage space. This is analogous to the well-known 3/spl times/3 "abc-qd" transformation developed for the three-leg inverter. Details of this new 4/spl times/4 "Quad" transform are provided, along with a depiction of the voltage-vectors produced. Advanced synchronous-frame control techniques are applied with this 4-to-3 "abcn-qdo" transform to create a UPS-style inverter with sinewave output. Experimental results for an 8.6 kVA prototype inverter are presented.

New control algorithms for series and shunt three-phase four-wire active power filters

This paper presents the general equations that relate the new concepts of instantaneous active and reactive power theory and the well known theory of Symmetrical Components, for the case of 3-phase 4-wire systems, where zero sequence components and harmonics may be present in both voltages and currents. Based on these equations, new control algorithms for 3-phase 4-wire shunt and series active filters for unbalanced power systems are proposed and validated through simulations. The control algorithms presented here are very important for active power filter design and also for FACTS technology reactive power compensators. >