Harmonic reduction using a novel multipulse AC-DC converter

2018 ◽  
Vol 15 (4) ◽  
pp. 520-530 ◽  
Author(s):  
Rohollah Abdollahi
Keyword(s):  
Power Quality ◽  
Harmonic Distortion ◽  
Pulse Number ◽  
Main Concern ◽  
Content Type ◽  
Current Harmonics ◽  
Harmonic Reduction ◽  
Light Load ◽  
Simulation Results ◽  
The Cost

Purpose For direct torque controlled induction motor drives, an effective solution to eliminate harmonics is the use of multipulse alternating current (AC)-direct current (DC) converters. Many researchers have used different configurations based on 24- and 30-pulse rectifications for improved power quality. However, the total harmonic distortion (THD) of AC mains current with these topology is more than 4 per cent when operating at a light load. For mitigating the THD problems observed in the input currents, Abdollahi propose 40-, 72- and 88-pulse AC-DC converters, while the power quality enhancement was the main concern. It is known that by increasing the number of pulses further results in reduction in current harmonics, but this is accompanied by an increase in cost and complexity. In this context, the purpose of this paper is to design a new delta/hexagon transformer based 36-pulse AC-DC converter for harmonic reduction without increasing the cost and complexity. Design/methodology/approach The proposed converter consists of two paralleled 18-pulse AC-DC converters involving a nine-phase shifted uncontrolled diode bridges with an interphase transformer circuit. Findings In this paper, the proposed scheme is simulated by matrix laboratory (MATLAB)/SIMULINK considering different loading scenarios. The simulation results show that the proposed scheme improves the power quality indices and satisfies the The Institute of Electrical and Electronics Engineers (IEEE)-519 requirements at the point of common coupling. Also, a laboratory prototype is implemented using the proposed design, and the experimental results confirm the simulation results under different loading conditions. Originality/value The proposed solution is a tradeoff among the pulse number, the transformer platform, the complexity of the scheme and the cost. The proposed scheme has an optimized configuration in this regard.

A 12-pulse rectifier with passive harmonic reduction based on UIPT in more electric aircrafts

Circuit World ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Rohollah Abdollahi
Keyword(s):  
Power Factor ◽  
Harmonic Distortion ◽  
Cost Savings ◽  
Cost Effective ◽  
Industrial Applications ◽  
Input Current ◽  
New Combination ◽  
Content Type ◽  
Harmonic Reduction ◽  
Simulation Results

Purpose The purpose of this paper is to provide a T autotransformer based 12-pulse rectifier with passive harmonic reduction in more electric aircraft applications. The T autotransformer uses only two main windings which result in volume, space, size, weight and cost savings. Also, the proposed unconventional inter-phase transformer (UIPT) with a lower kVA rating (about 2.6% of the load power) compared to the conventional inter-phase transformer results in a more harmonic reduction. Design/methodology/approach To increase rating and reduce the cost and complexity of a multi-pulse rectifier, it is well known that the pulse number must be increased. In some practical cases, a 12-pulse rectifier (12PR) is suggested as a good solution considering its simple structure and low weight. But the 12PR cannot technically meet the standards of harmonic distortion requirements for some industrial applications, and therefore, they must be used with output filters. In this paper, a 12PR is suggested, which consists of a T autotransformer 12PR and a passive harmonic reduction (PHR) based on the UIPT at direct current (DC) link. Findings To show the advantage of this new combination over other solutions, simulation results are used, and then, a prototype is implemented to evaluate and verify the simulation results. The simulation and experimental test results show that the input current total harmonic distortion (THD) of the suggested 12PR with a PHR based on UIPT is less than 5%, which meets the IEEE 519 requirements. Also, it is shown that in comparison with other solutions, it is cost effective, and at the same time, its power factor is near unity, and its rating is 29.92% of the load rating. Therefore, it is obvious that the proposed rectifier is a practical solution for more electric aircrafts. Originality/value The contributions of this paper are summarized as follows. The suggested design uses a retrofit T autotransformer, which meets all technical constraints, and in comparison, with other options, has less rating, weight, volume and cost. In the suggested rectifier, a PHR based on UIPT at its dc link of 12PR is used, which has good technical capabilities and lower ratings. In the PHR based on UIPT, an IPT is used, which has an additional secondary winding and four diodes. This solution leads to a reduction in input current THD and conduction losses of diodes. In full load conditions, the input line current THD and power factor are 4% and 0.99, respectively. The THD is less than 5%, which satisfies IEEE-519 and DO-160G requirements.

scholarly journals Harmonic Distortion Prediction Model of a Grid-Tie Photovoltaic Inverter Using an Artificial Neural Network

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 790 ◽  
Author(s):  
Matej Žnidarec ◽  
Zvonimir Klaić ◽  
Damir Šljivac ◽  
Boris Dumnić
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Power Quality ◽  
Prediction Models ◽  
Harmonic Distortion ◽  
Pv System ◽  
Current Harmonics ◽  
Pv Systems ◽  
Input Parameters ◽  
Artificial Neural

Expanding the number of photovoltaic (PV) systems integrated into a grid raises many concerns regarding protection, system safety, and power quality. In order to monitor the effects of the current harmonics generated by PV systems, this paper presents long-term current harmonic distortion prediction models. The proposed models use a multilayer perceptron neural network, a type of artificial neural network (ANN), with input parameters that are easy to measure in order to predict current harmonics. The models were trained with one-year worth of measurements of power quality at the point of common coupling of the PV system with the distribution network and the meteorological parameters measured at the test site. A total of six different models were developed, tested, and validated regarding a number of hidden layers and input parameters. The results show that the model with three input parameters and two hidden layers generates the best prediction performance.

Islanding Detection in a Distribution System with Modified DG Interface Controller

2017 ◽  
Vol 6 (3) ◽  
pp. 135 ◽  
Author(s):  
Abbineni Sai Subhadra ◽  
P.Linga Reddy ◽  
Shailesh . B Modi
Keyword(s):  
Power Quality ◽  
Distributed Generation ◽  
Distribution System ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Detection Methods ◽  
Islanding Detection ◽  
Detection Zone ◽  
Current Harmonics ◽  
Crucial Problem

Islanding detection of Distributed Generation (DG) is considered as one of the most important aspects when interconnecting DGs to the distribution system. It was the crucial problem in distributed generation. This detection phenomenon having a great importance. These detection methods are divided into active and passive islanding detection. These two methods are based on changing in parameters such as frequency, voltage and current harmonics. But these methods have some challenges such as reduction in power quality and large Non Detection Zone (NDZ). In this paper, the proposed method is change of Total harmonic distortion (THD) will be studied for islanding detection diagnosis. The studied system was considered by following the standard IEEE-1547 and UL-1741.The system was simulated using MATLAB/ SIMULINK.

Cloud storage for digital preservation: optimal uses of Amazon S3 and Glacier

2015 ◽  
Vol 33 (2) ◽  
pp. 261-271 ◽  
Author(s):  
Yan Han
Keyword(s):  
Cloud Storage ◽  
Data Transfer ◽  
Digital Preservation ◽  
Data Retrieval ◽  
Main Concern ◽  
Cost Models ◽  
Retrieval Models ◽  
Content Type ◽  
Storage Solutions ◽  
The Cost

Purpose – The purpose of this paper is to use cloud storage in digital preservation by analyzing the pricing and data retrieval models. The author recommends strategies to minimize the costs and believes cloud storage is worthy of serious consideration. Design/methodology/approach – Few articles have been published to show the uses of cloud storage in libraries. The cost is the main concern. An overview of cloud storage pricing shows a price drop once every one or one-and-a-half years. The author emphasize the data transfer-out costs and demonstrate a case study. Comparisons and analysis of S3 and Glacier have been conducted to show the differences in retrieval and costs. Findings – Cloud storage solutions like Glacier can be very attractive for long-term digital preservation if data can be operated within the provider’s same data zone and data transfer-out can be minimized. Practical implications – Institutions can benefit from cloud storage by understanding the cost models and data retrieval models. Multiple strategies are suggested to minimize the costs. Originality/value – The paper is intended to bridge the gap of uses of cloud storage. Cloud storage pricing especially data transfer-out pricing charts are presented to show the price drops over the past eight years. Costs and analysis of storing and retrieving data in Amazon S3 and Glacier are discussed in details. Comparisons of S3 and Glacier show that Glacier has uniqueness and advantages over other cloud storage solutions. Finally strategies are suggested to minimize the costs of using cloud storage. The analysis shows that cloud storage can be very useful in digital preservation.

scholarly journals Power Quality Improvement by Reduction of Total Harmonic Distortion (THD) using PWM Inverter

2020 ◽  
Vol 9 (2) ◽  
pp. 1641-1643
Keyword(s):  
Quality Improvement ◽  
Power Quality ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Nonlinear Loads ◽  
Pwm Inverter ◽  
System A ◽  
Power Quality Improvement ◽  
Simulation Results ◽  
And Performance

In this paper, a PWM inverter is proposed for improvement of power quality i.e., reduction of total harmonic distortion (THD). The power quality problems reduce the lifetime and performance of equipments. The proposed system reduces the THD which is generated from the nonlinear loads. Because presence of harmonics leads to problems like overheating, failure of insulation etc. Here the simulation results of the proposed system is studied using MATLAB SIMULINK. Using the system, a lower THD is achieved which shows the effectiveness of the system.

scholarly journals Harmonic aggregation techniques for power quality assessment a standard framework

2014 ◽  
Vol 3 (3) ◽  
pp. 365
Author(s):  
Mohammad Mahdy Share Pasand ◽  
Zahra Rahmatian
Keyword(s):  
Power Quality ◽  
Electromagnetic Compatibility ◽  
Simple Technique ◽  
Harmonic Distortion ◽  
Future Research ◽  
Simulation Studies ◽  
Current Harmonics ◽  
Harmonic Currents ◽  
Aggregation Techniques ◽  
Standard Framework

A review on the existing methods for aggregation of harmonic currents including recommended method used in IEC 61000-3-6 standard is performed and different approaches are compared. Main advantages of each method are outlined and simulation studies are performed to assess each method. A simple technique is proposed to base future research and standardization on. The proposed technique is simple, reliable and realistic though requires experimental data to derive parameters. Keywords: Electromagnetic Compatibility; Harmonic Distortion; Harmonic Aggregation; Power Quality; Current Harmonics.

PV based DG Power Quality Improvement Using Integrated D-STATCOM under varying Insolation

2021 ◽  
Vol 9 (11) ◽  
pp. 1848-1855
Author(s):  
Lakshmi Sravya Kanukolanu
Keyword(s):  
Power Quality ◽  
Power Plants ◽  
Reactive Power ◽  
Harmonic Distortion ◽  
Voltage Control ◽  
Electrical Energy ◽  
Total Harmonic Distortion ◽  
Static Synchronous Compensator ◽  
Pv Systems ◽  
Simulation Results

Abstract: The standalone grid connected Photovoltaic (PV) systems have been gradually increasing for generation of electrical energy due to ever increasing fuel and coal prices, as well as the environmental issues posed by conventional power plants. In this transition phase, power quality is at its expense, resulting in damage to equipment or appliances and lost in production. Inadequate power quality can be caused by network failures and switching operations, which primarily cause voltage dips, interruptions, transients, and network disturbances from loads which primarily produce flicker i.e., rapid voltage changes, harmonics and phase imbalance. In this paper PV is used as an external DC source for D-STATCOM (Distributed Static Synchronous Compensator) which is a FACTS device that can maintain and repair power quality limitations such as power factor correction, voltage control, load balancing and harmonic reduction. The PV-STATCOM system inverter is implemented by impending MPPT method using P&O algorithm so as to provide DC link voltage control and to improve transient response along with counteracting power quality issues. MATLAB/Simulink based simulation results are presented for the proposed PVSTATCOM model. The simulation results proves that the PV-STATCOM system has better Total Harmonic Distortion (THD) and good reactive power compensation at different irradiance levels. Keywords: Photovoltaic (PV) systems, D-STATCOM (Distributed Static Synchronous Compensator), Total Harmonic Distortion (THD), MPPT (Maximum Power Point Tracking), FACTS (Flexible AC Transmission System)

Influence of microdimple on lubrication performance of textured plunger pump

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hekun Jia ◽  
Zeyuan Zhou ◽  
Bifeng Yin ◽  
Huiqin Zhou ◽  
Bo Xu
Keyword(s):  
Peer Review ◽  
Surface Texture ◽  
High Performance ◽  
Combustion Engine ◽  
Surface Texturing ◽  
Laser Surface Texturing ◽  
Content Type ◽  
Lubrication Performance ◽  
Simulation Results ◽  
The Cost

Purpose The purpose of this study is to investigate the influence of dimple radius, depth and density on the lubrication performance of the plunger. Design/methodology/approach A lubrication model was adopted to consider eccentricity and deformation during the working process of the plunger, and a rig test was performed to confirm the simulation results. The texture was fabricated using laser surface texturing. Findings The simulation results suggested that when dimple radius or depth increases, oil film thickness of the plunger increases before decreasing, and asperity friction displays an opposite trend. Therefore, appropriate microdimple texture could facilitate lubrication performance improvement and reduce the wear. Microdimples were then lased on the plunger surface, and a basic tribological test was conducted to validate the simulation results. The experimental results suggested that the average friction coefficient decreased from 0.18 to 0.13, a reduction of 27.8%. Social implications The introduction of microdimple on a plunger couple to reduce friction and improve lubrication is expected to provide a new approach to developing high-performance plunger couple and improve the performance of the internal combustion engine. If applied, the surface texture could help reduce friction by around 27% and cap the cost relative to the plugger friction. Originality/value The microdimple texture was introduced into the plunger couple of a vehicle to reduce the friction and improve the performance. Findings suggested that surface texture could be used in the automotive industry to improve oil efficiency and lubrication performance. Peer review The peer review history for this article is available at: http://dx.doi.org/10.1108/ILT-07-2020-0259.

scholarly journals Demand-Side Management for Improvement of the Power Quality in Smart Homes Using Non-Intrusive Identification of Appliance Usage Patterns with the True Power Factor

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4837
Author(s):  
Hari Prasad Devarapalli ◽  
Venkata Samba Sesha Siva Sarma Dhanikonda ◽  
Sitarama Brahmam Gunturi
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Distribution Systems ◽  
Low Voltage ◽  
Harmonic Distortion ◽  
Smart Homes ◽  
Demand Side Management ◽  
Usage Pattern ◽  
Demand Side ◽  
Current Harmonics

The proliferation of low-power consumer electronic appliances (LPCEAs) is on the rise in smart homes in order to save energy. On the flip side, the current harmonics induced due to these LPCEAs pollute low-voltage distribution systems’ (LVDSs’) supplies, leading to a poor power factor (PF). Further, the energy meters in an LVDS do not measure both the total harmonic distortion (THD) of the current and the PF, resulting in inaccurate billing for energy consumption. In addition, this impacts the useful lifetime of LPCEAs. A PF that takes the harmonic distortion into account is called the true power factor (TPF). It is imperative to measure it accurately. This article measures the TPF using a four-term minimal sidelobe cosine-windowed enhanced dual-spectrum line interpolated Fast Fourier Transform (FFT). The proposed method was used to measure the TPF with a National Instruments cRIO-9082 real-time (RT) system, and four different LPCEAs in a smart home were considered. The RT results exhibited that the TPF uniquely identified each usage pattern of the LPCEAs and could use them to improve the TPF by suggesting an alternative usage pattern to the consumer. A positive response behavior on the part of the consumer that is in their interest can improve the power quality in a demand-side management application.

A multi-valve controlled saturable reactor and its harmonic optimization

2014 ◽  
Vol 33 (4) ◽  
pp. 1346-1365 ◽  
Author(s):  
Yifan Wang ◽  
Guozhu Chen
Keyword(s):  
Mathematical Model ◽  
Harmonic Analysis ◽  
Harmonic Distortion ◽  
Iron Core ◽  
Harmonic Suppression ◽  
Output Current ◽  
Harmonic Compensation ◽  
Content Type ◽  
Current Harmonics ◽  
The Mathematical Model

Purpose – As arc suppression coils (ASCs), magnetically controlled reactors (MCRs) are usually operated in the single-phase mode. Due to the lack of a third order harmonic compensation circuit, the current harmonics are high. The purpose of this paper is to propose a novel structure of MCR and a genetic algorithm (GA) to determine the parameters which will result in minimum total harmonics. Design/methodology/approach – This paper proposes the structure and the working principle of the multi-valve controlled saturable reactor (MCSR). There are several sorts of magnetic valves in the iron cores of the MCSR. The saturation degree of each magnetic valve is different when the same direct component of the magnetic flux is generated in the iron core, therefore current harmonics of different phases emerging, i.e. the total harmonics can be reduced. The magnetization characteristics and the mathematical model of the current harmonics of the MCSR are presented by introducing three parameters. The optimal values of the parameters that result in the smallest total harmonic distortion in the output current are calculated by a GA. Findings – The simulation and experimental results are coincident with the theoretical analyses, which prove the effectiveness of the proposed method on harmonic suppression. Practical implications – The method proposed in this paper can successfully reduce the current harmonics of the conventional MCR, including but not limited to the ASC. A prototype MCSR (540 kVA/10 kV) has been designed and constructed. Originality/value – In this paper, a MCSR is proposed. The mathematical model of the MCSR for harmonic analysis is developed. The optimal parameters that result in the smallest THD in the output current are calculated. The mathematical model can be also used for the harmonic analysis of conventional MCRs.

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