Supply Current Distortion Research Articles

Study of Harmonic Minimization in Pulp and Paper Mill using Hybrid Active Filter -A Case Study

Increased power electronics-based nonlinear loads have harmed distribution system power quality. Variable speed drives, switched-mode power supply, and DC drives impair power quality and affect customers and utilities. Many variable-speed drives in the paper mill cause harmonic distortion, a power quality issue. This study investigates the impact of nonlinear electric drives on supply current distortion in Padmavati Pulp and Paper Mill, Ambarnath, Thane, India. Harmonic analysis is done at PCC, that is, at the secondary side of the transformer, with the help of a power quality analyzer fluke-434. Based on detailed analysis, a suitable harmonic reduction method is identified. passive filters, are the simplest solution for lowering harmonic currents but it has shortcomings like bulk size and cause resonance. In recent years active filter has been applied as an effective solution for harmonic reduction. This study suggests a hybrid filter as an economical solution to take advantage of a passive and active harmonic filter. This work present design and simulation of cascade H- bridge multilevel inverter-based hybrid filter for medium and high-power distribution system. The system for the case study is developed in MATLAB Simulink platform with suitable harmonic mitigation techniques and performance is evaluated in terms of total Harmonic Distortion Index (THDi).

Alternative Performance Indices-Based Control Technique for a Unity Power Factor Three-Phase Rectifier

The implementation of a unity power factor (UPF) three-phase rectifier has the potential to enhance the power factor (PF). However, the PF and total harmonic distortion (THD) experience degradation in low-output regions due to the utilization of a “critical input inductor” under rated load conditions. In this study, an analysis of the operation principle of a UPF three-phase rectifier is conducted and a reference compensation current technique based on alternative performance indices is proposed. The optimal control algorithm is utilized to calculate the single harmonic phase delay of each phase and determine the compensator gain, taking into account factors such as the single harmonic distortion limit, THD limit, PF, and active power consumption. The output of the current compensator serves as the desired current source, which in turn drives the bidirectional switches. The simulation and experimental results demonstrate that the proposed control technique can significantly mitigate power supply current distortion, and the input power factor has been effectively improved within a wider load range.

Sensorless Single-Switch PFC Converter Fed Brushless Direct Current Motor Ceiling Fan

This work deals with the reduction in total harmo-nics distortion, power input, and a supply power factor correction (PFC) of permanent-magnet brushless direct-current motor (PMBLDCM) ceiling fan (CF) to get reduced bills for the consumers. To address these supply power-quality issues in the existing PMBLDCM-CF, a single-stage, single-switch boost-flyback power-factor-correction-converter (S4BF-PFCC) is employed at the front-end. The front-end PFCC is designed in discontinuous conduction mode, which offers inherent supply PFC. The high-frequency-transformer (HFT) auxiliary-voltage is utilized as a feedback to get the controlled PFCC voltage output (VDC), and with this controlled VDC, CF speed is controlled. This method eliminates the required DC-link sensor or sensing circuitry. Moreover, the back-EMF sensorless-control is used to eliminate the Hall sensors and their auxiliary supply. The speed control with a variable output voltage of front-end PFCC allows an inverter to work at a commutation frequency, which offers low switching losses and improves CF efficiency. This CF system is modelled and simulated in MATLAB/Simulink. Its simulation and test results are compared to validate the design. The supply current harmonics distortion of CF meets the IEC standard 61000-3-2.

A new flowchart for parameters calculation of Hybrid Active Power Filter with Injection Circuit.

This paper presents a new flowchart for parameters calculation of Hybrid Active Power Filter with Injection Circuit (IHAPF). The first is the necessity to use the IHAPF model and the parameters of the IHAPF needed to search have been shown. Next, the constraints of the parameters to be searched and the objective function to be reached are given. Since then a flowchart is designed to look for parameters of IHAPF using the Jaya optimization algorithm. The Jaya algorithm has the advantage of simplicity, few parameters, and good performance. Therefore it reduces search time. Compared to the flowchart using the firefly algorithm, particle swarm optimization algorithm, and simulated annealing algorithm, the simulation results performed on an IHAPF 10kV-50Hz model have proven that: the proposed flowchart gives better results in minimizing the compensation errors, minimum phase shift angle between supply current, and source voltage, minimum total harmonic distortion of supply current.

Simulink Implementation of Voltage Stability Improvements Using STATCOM based 5-level Diode Clamped Converter

In this paper, a STATCOM based on Five-level Diode Clamped Multilevel Converter is used to maintain the bus voltage at specific bus bar in a suggested grid under various abnormal conditions like 2-phase to ground fault, load disturbance and source disturbance. The suggested grid consists of a single machine, transmission line and loads. The compensation procedure is carried out and compared between the two suggested control methods, the first method was the traditional control method using Phase Shifted-PWM controller which is used to improve the voltage profile. The Second one was the Finite Set-Model Predictive Controller for improving the voltage profile. The simulation results show that the two methods provided significant improvements of the bus voltage profile. Moreover, the improvement of voltage profile using FS-MPC method is less over shoot and attains a steady state better than the conventional PS-PWM when the system is subjected under many disturbances. The results of the harmonic effect show low values of total harmonic distortion (THD) of supply voltage and current.

Stability Analysis of Shunt Active Power Filter with Predictive Closed-Loop Control of Supply Current

This paper presents a shunt active power filter connected to the grid via an LCL coupling circuit with implemented closed-loop control. The proposed control system allows selective harmonic currents compensation up to the 50th harmonic with the utilization of a model-based predictive current controller. As the system is fully predictive, it provides high effectiveness of the harmonic reduction, which is proved by waveforms achieved in performed tests. On the other hand, the control system is prone to loss of stability. Therefore, the paper is focused on the stability analysis of the discussed control system with the additional outer control loop of the supply current with predictive control of this current. The conducted stability analysis encompasses the assessment of system stability as a function of the coupling circuit parameter identification accuracy, whose values are implemented in the current controller, as well as parameters such as the sampling frequency and proportional-integral (PI) controller coefficients. The obtained results show that the ranges of the LCL circuit parameter identification accuracy for which the system remains stable are relatively wide. However, the most effective compensation of the supply current distortion is achieved for the parameters identified correctly, and the greatest impact on the compensation quality has the value of L1 inductance.

On‐board electric vehicle battery charger with improved power quality and reduced switching stress

Development of charging infrastructure is one of the key factors for the successful operation of electric vehicles. This study proposes a power converter for on-board electric vehicle battery charger suitable with universal input voltage (85–265 V). The proposed converter is able to make better power quality by the reduction in total harmonic distortion (THD) of supply current, power factor correction and accurate output voltage regulation. System configuration includes diode bridge rectifier followed by three-level DC–DC SEPIC converter which emphasises on the reduction of voltage stress and switching loss across switches, thereby reduces the switch rating and improves the overall efficiency of the converter. The converter employs a duty cycle feed-forward controller scheme for charging the battery at constant voltage (CV) and constant current (CC) mode. Incorporating the above-said controller scheme has benefits of low THD in supply current, make power factor unity and nearly no zero-crossing detection. The proposed power factor correction converter system analysis is executed in continuous conduction mode. The system performance is evaluated with 400 V, 48 AH battery charging under CV and CC mode through MATLAB/Simulink and experimentation. To estimate the features of power quality indices like power factor and THD is recorded under the wide range of supply variations.

Power quality improvement of solar power plants in grid connected system using novel Resilient Direct Unbalanced Control (RDUC) technique

Distributed Generation systems (DGs) using solar power is one of the new trends in power generation. These distributed generating units are integrated to form a micro grid to serve the loads among the locality, which is in connection with the utility grid for power transmission. The elimination of the harmonics in the grid and the usage of solar energy resources in the power electronics applications become famous worldwide. In this work, a Resilient Direct Unbalanced Control (RDUC) algorithm is used to improve the performance of the controller by achieving optimal numerical parameters for photovoltaic power generation - Unified Power Quality Conditioner (PV-UPQC). Then the voltage sag, swell and elimination of current harmonics are used to study the effects of proposed RDUC algorithm for photovoltaic feed UPQC system. According to the evaluations, the proposed unified power quality conditioner eliminates both the supply current distortion caused by a non-linear load and the load voltage distortion introduced after adding fifth and seventh harmonics to the Alternating Current (AC) mains voltage. To validate the simulation results of Resilient Direct Unbalanced Control scheme, tests are performed under various operating conditions. Test results show the satisfactory behavior under steady state, and dynamic conditions such as load unbalance, insolation variation, voltage sag and swell. Finally, Total Harmonic Distortions (THDs) of proposed optimization-based grid current and grid voltages found within limits of the IEEE standard.

Analysis of Multiaxis Current Controller for Power System Friendly Front-End Converter Employing Two-Level and Three-Level Topologies

It is highly essential to develop a control technique that can be applied to conventional two-level as well as high-power multilevel front-end converters (FECs). Multiaxis current controlled, unity power factor (PF), regenerative FEC is described in this article. Current error space phasor is controlled by multiaxis current monitoring and its movement is confined within the prescribed hexagonal boundary. It is shown that the needed information on sector change detection can be derived from instantaneous values of supply voltages for the two-level FECs. However, similar approach cannot be extended for three-level FECs. Hence, sector change detection technique employing additional outer hysteresis band is proposed. With the help of experimental results, for steady state and dynamic conditions of FEC, it is demonstrated that the proposed current-controlled technique is equally applicable to two-level and three-level FECs. A three-level flying capacitor topology is considered, where voltage balancing of flying capacitors is guaranteed by effective utilization of redundant switching states. Results clearly depict the power system friendly nature of the presented scheme, i.e., unity PF, low total-harmonic distortion in supply current, good load and line regulations, and capacitor voltage balancing with regenerative capability of the converter. All the schemes are implemented on OPAL-RT hardware-in-loop platform.

Computational intelligence based control of cascaded H-bridge multilevel inverter for shunt active power filter application

This work proposes computational intelligence based control of five-level cascaded H-bridge inverter (5LCHB) for an application of shunt active power filter (SAPF) to reduce total harmonic distortion (THD) in supply current under nonlinear loads. Active and reactive power (PQ) method is used to extract reference currents. The proposed controller is effectively verified for three different carrier based pulse width modulation methods such as phase disposition (PD), phase opposition disposition (POD) and alternate phase opposition disposition (APOD). The required rules for fuzzy logic controller (FLC) are set by human brain computation. The performance of computational intelligence based FLC is implemented and is verified for reduction of THD under nonlinear loads. The DC voltage balance is achieved using the proposed controller. The proposed work is carried out in the environment of Matlab Simulink. The comparative performance analysis of THD in source current, individual harmonics (5th, 7th, 11th, and 13th), power factor (PF), real power, and reactive power compensation (RPC) for APOD, POD and PD using both PI and FLC are presented.

Investigation of Power Quality Improvement in Super Lift Luo Converter

<p align="justify">This paper presents the improved single phase AC-DC super lift Luo converter for enhancing quality of power by mitigating the issues. The proposed converter is used for output voltage control, power factor improvement and reduced source current harmonics at supply side. The main intention of this work is to design appropriate closed loop controllers for this AC-DC super lift Luo converter to achieve unity power factor in the source end. The designed control system comprises of two control loops, voltage control in outer loop and the current controller is devised in the inner loop. Fuzzy controller is used for current controller whereas PI controller as voltage controller. In the MATLAB/SIMULINK platform, simulation of the proposed AC-DC super lift Luo converter is done. It is clear from the simulation results that PI integrated fuzzy controller for voltage and control is proven to be better than classical PI with hysteresis controllers. The proposed system is able to achieve high input power factor along with supply current harmonic distortions of less than 5%.</p>

Nonlinear Adaptive Volterra Filter for Control of Distribution Static Compensator

This paper presents nonlinear adaptive Volterra filter for control of three-phase four wires Distribution Static Compensator under mixed type linear and nonlinear load. The proposed adaptive filter identifies and measures active and reactive weights of the fundamental components of load currents. These weights are used to generate the reference signals such that the currents drawn from a supply are close to balanced and sinusoidal. The performance of the proposed control algorithm is observed under nonlinear load in the laboratory environment. The test results are found satisfactory as total harmonic distortion in supply currents are within the 5% levels specified by the IEEE Standard 519-1992.

Dual-Tree Complex Wavelet Transform-Based Control Algorithm for Power Quality Improvement in a Distribution System

This paper presents a dual tree-complex wavelet transform-based control algorithm for a distribution static compensator (DSTATCOM) to improve the power quality (PQ) in a distribution system. PQ disturbances like harmonics and starting as well as ending of unbalancing in all phase load currents are also assessed simultaneously. The distorted load current of each phase is decomposed into various frequency levels with this technique to extract respective line frequency component for the estimation of the reference active power component. The deviations of respective sensed load currents from these estimated reference components are used to generate the reference currents for the control of voltage source converter used as DSTATCOM. Simulated performance of DSTATCOM is presented at varying load conditions. The proposed control algorithm is also validated experimentally on a laboratory prototype of DSTATCOM. The total harmonic distortion (THD) of supply current is obtained below 5 percent with unity power factor under different load conditions which is satisfactory as per IEEE-519 standard.

A 4-ary Control Algorithm for Direct Power Control of Three Phase Pulse Width Modulated Rectifier

Objectives: The Direct Power Control (DPC) strategy for front end Pulse Width Modulated (PWM) rectifier employing binary hysteresis controller with two digital outputs and a new 4-ary control algorithm with four digital outputs is investigated. Methods/Analysis: The prototype DPC-PWM rectifier based on conventional binary algorithm and proposed 4-ary control algorithm for hysteresis controllers is designed and modeling and simulation was performed in MATLAB/ SIMILINK® environment. The total harmonic distortion of supply current and average switching frequency under steady state are measured for a load of wide dynamic range for different hysteresis widths. The DC output voltage ripples and power ripples are also observed. Findings: It was found that the total harmonic distortion in supply current was reduced and remained bounded within narrow range in 4-ary control as compared to binary control. The average switching frequency also remained bounded within narrow range in proposed control as compared to conventional hysteresis control. The DC output voltage ripples and power ripples were found to be reduced considerably at heavy loads as compared to binary control. Novelty/Improvement: The tight control of active and reactive powers not only around the hysteresis band but also within the hysteresis band is achieved with simple algorithm.

PI Controlled Active Front End Super-Lift Converter with Ripple Free DC Link for Three Phase Induction Motor Drives

An active front end (AFE) is required for a three-phase induction motor (IM) fed by a voltage source inverter (VSI), because of the increasing need to derive quality current from the utility end without sacrificing the power factor (PF). This study investigates a proportional-plus-integral (PI) controller based AFE topology that uses a super-lift converter (SLC). The significance of the proposed SLC, which converts rectified AC supply to geometrically proceed ripple-free DC supply, is explained. Variations in several power quality parameters in the intended IM drive for 0% and 100% loading conditions are demonstrated. A simulation is conducted by using MATLAB/Simulink software, and a prototype is built with a field programmable gate array (FPGA) Spartan-6 processor. Simulation results are correlated with the experimental results obtained from a 0.5 HP IM drive prototype with speed feedback and a voltage/frequency (V/f) control strategy. The proposed AFE topology using SLC is suitable for three-phase IM drives, considering the supply end PF, the DC-link voltage and current, the total harmonic distortion (THD) in supply current, and the speed response of IM.

Design and simulation of a unified power quality conditioner fed by solar energy

Presently, quality problems in grid-integrated applications take great interest because of the growing applications in power electronics. The elimination of the harmonics in the grid and the usage of clean energy resources in the power electronics applications become popular world widely. In the present paper, a unified power quality conditioner fed by solar energy which can also export active power to the grid is proposed. The conditioner uses a photovoltaic (PV) system and its topology is made up of a hybrid active power filter combination. This combination bases on a parallel active power filter, which shares a common DC voltage assured by the photovoltaic system with a serial active power filter. According to the analyzes, the proposed unified power quality conditioner eliminates both the supply current distortion caused by a non-linear load and the load voltage distortion introduced after adding fifth and seventh harmonics to the AC main voltage. In addition, the proposed unified power quality conditioner exports the photovoltaic power to the grid using a boost converter, perturbed and observed maximum power point tracking algorithm, compensates the reactive power and filters the current and voltage harmonics confirmed by the total harmonic distortion values, such as 4.76% and 3.86%, respectively. The design and the analyses have been performed with MATLAB/Simulink software. The simulation system determines the performances of such system and offers future perspectives on unified power quality conditioners.

Closed Loop Non Linear Control of Shunt Hybrid Power Filter for Harmonics Mitigation in Industrial Distribution System

In recent years, the amount of non-linear loads has been increasing considerably since there are improvements in power electronic equipment (such as adjustable speed drives or converter ac-dc, ac-ac, dc-ac and dc-dc) in industrial sectors which cause deterioration of the quality of the electric power supply through distortion of supply voltage and supply current. This has led to improvement of many stringent needs regarding generation of harmonic current, which are found in IEEE519 and IEC61000 standards. This paper proposes a non-linear function based closed loop control strategy (without load current extraction) for three-phase Shunt Active Power Line Conditioner and LC passive filter to compensate harmonics, power factor improvement and enhance the dynamic performance of Shunt Hybrid Power Filter (SHPF). By using a PI controller the DC bus voltage of the Shunt Active Power Filter is maintained constant. Results obtained from simulation shows the performance of expected hybrid filter in transient and steady state operation .This indicates that the controller is able to compensate even under severe load current imbalances. DOI: http://dx.doi.org/10.11591/ijpeds.v5i2.6181

Adaptive Modified Hysteresis Current Control for Reduction of Switching Losses in Grid Connected Solar Inverters

Current Control logic plays an important role in the performance of Grid connected inverters. In the present work Adaptive Modified Hysteresis controller has been used for generation of switching pulses to the minimally switched grid connected inverter. Different from the previous works the new control logic helps in maintaining the instantaneous switching frequency low and nearly constant with reduction of switching losses to one-third of that of the conventional type. Considerable reduction in Total harmonic distortion of supply current, better DC bus voltage stabilization, good reactive power compensation, satisfactory performance under unbalanced source and load conditions and good dynamic response is also achieved. The experimental verification is done using SIMULINK/REALTIME WINDOWS TARGET. Present control logic is compared with conventional hysteresis controller with and without adaptive control to prove the effectiveness.

Bridgeless single stage flyback converter-based computer power supply

A power factor corrected (PFC) bridgeless converter-based computer power supply (CPS) using multioutput flyback dc-dc converter is presented in discontinuous conduction mode (DCM) of operation. In place of the conventional diode bridge to convert ac voltage into uncontrolled dc voltage, two multioutput flyback converters are connected in anti-series across the single phase ac supply. The diode bridge at the front end is eliminated and the outputs of the two flyback converters are connected to two high frequency transformers, HFT-1 and HFT-2 respectively. Two multi-output flyback converters are operating alternately in positive and negative half cycles of the ac mains respectively to avoid the diode bridge at the front end. The proposed configuration of CPS offers low total harmonic distortion (THD) of supply current, low conduction losses due to the absence of diode bridge, high efficiency and good power factor (PF) with very simple control at full load as well as light load conditions. The performance of the proposed CPS meets the guidelines of international standards.

A robust 18-pulse diode rectifier with coupled reactors

A robust 18-pulse diode rectifier with coupled reactorsThe article presents the principle of operation and selected results of simulation and laboratory tests of the 18-pulse rectifier system with coupled reactors and small series active power filter. The presented system makes it possible to reduce, especially in distribution supply networks, undesired higher current harmonics. The 18-pulse nature of operation of the rectifier is reached using a set of coupled three-phase network reactors (CDT and CTR). The simultaneous use of the coupled reactors and the small active power filter provides opportunities for reduction of the supply current distortion, especially in case of voltage harmonic distortion and voltage unbalance.