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 Performance Between PFC Cuk and Bridgeless PFC Cuk Converter with Various Output Voltages

2019 ◽  
Vol 8 (2S2) ◽  
pp. 41-46
Keyword(s):  
Low Power ◽  
Power Factor ◽  
Single Phase ◽  
Harmonic Distortion ◽  
Input Current ◽  
Unity Power Factor ◽  
Cuk Converter ◽  
Maximum Current ◽  
Simulation Results ◽  
Power Application

This paper presents about the comparison between single-phase PFC Cuk converter and bridgeless PFC (BPFC) Cuk converter for low power application. This study attempts to investigate the characteristics of conventional and bridgeless PFC Cuk converter structures with three different output voltages and verified by the simulation results. The BPFC Cuk converter provides a lower Total Harmonic Distortion (THD) of input current than the conventional PFC Cuk converter. However, the conventional PFC Cuk converter has advantage of less maximum current stress at components compared to the BPFC Cuk converter. Conventional and BPFC Cuk converter can achieve an approximately unity power factor (PF).

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.

Study of the Influence of Control System Parameters on the Quality of the Input Current of a Three-Phase Power Factor Corrector

2021 ◽  
Vol 2 (2) ◽  
pp. 29-35
Author(s):  
Dmitry A. Sorokin ◽  
◽  
Sergey I. Volskiy ◽  
Jaroslav Dragoun ◽  
◽  
...  
Keyword(s):  
Control System ◽  
Power Factor ◽  
Harmonic Distortion ◽  
Total Harmonic Distortion ◽  
Input Current ◽  
System Operation ◽  
Error Amplifier ◽  
Three Phase ◽  
Power Factor Corrector

The paper suggests a control system of a three-phase power factor corrector. The study of the control system operation is carried out and the expressions for calculating the permissible values of error amplifier factors are obtained. The influence of the error amplifier parameters on phase current quality is investigated. The dependence of total harmonic distortion input current on a combination of error amplifier parameters is obtained at a given value of power factor. The conditions under which the total harmonic distortion input current has the minimum value are found out. This article is of interest to power electronics engineers, who are aimed at developing a three-phase power factor corrector.

Cyient: enabling innovation through idea tree initiative

2020 ◽  
Vol 10 (3) ◽  
pp. 1-26
Author(s):  
Nidheesh Joseph ◽  
Upam Pushpak Makhecha
Keyword(s):  
Innovation Management ◽  
Innovation Process ◽  
Cost Savings ◽  
Cost Effective ◽  
Process Models ◽  
Innovation Activity ◽  
Business Unit ◽  
Content Type ◽  
Academic Level ◽  
Digital Format

Learning outcomes The case would help students to learn the concept of high involvement innovation activity and how to apply it in large service organizations to increase innovation involvement. The case will help the students to reflect on the significance of organizing structure and culture of an organization for enabling innovation and innovation process models. The case would further help the students to develop the skill to plan and implement simple, innovative innovation process models which will increase the ideation capabilities of the organization. The students will also be able to understand the role of informal learning in innovation and how to facilitate it. Case overview/synopsis Cyient – a global services firm – had always focused on innovation as a key strategic capability winning various annual client awards for over a decade. However, in 2012, Cyient missed the innovation awards which led to the introduction of Idea Tree initiative in Aerospace & Defense (AED) business unit of Cyient. Cyient was able to co-create patents and offer cost savings to its clients through the Idea Tree initiative. This cost-effective and unique initiative resulted in re-organizing the structure (from formal to a quasi-formal), culture (open to new ideas, mistakes and failures) and process (stage-gate) inside Cyient AED business unit. However, Idea Tree also suffers from challenges such as lack of a digital format, lack of corporate presence across Cyient and its highly informal nature. In this context, the CEO wants to review the Idea Tree initiative to decide on its future in Cyient. Complexity academic level The case is suitable for teaching multiple facets of innovation for MBA and Executive MBA classes in core Strategy, Managing Organizations and Entrepreneurship and for elective courses such as Innovation Management, Organizing for Innovation or HRM for Innovation. The case is suitable for both fresher and experienced participants. Supplementary materials Teaching Notes are available for educators only. Subject code CSS 6: Human Resource Management.

scholarly journals Performance Analysis of Three Phase Two Quadrant Controlled Converter for DC Load Applications

2019 ◽  
pp. 679-685
Author(s):  
S. T. Siddharthan ◽  
O. R. Sai Ayyappa ◽  
K. Karthik Kumar
Keyword(s):  
Performance Analysis ◽  
Power Factor ◽  
Duty Cycle ◽  
Harmonic Distortion ◽  
Input Current ◽  
Current Waveform ◽  
Harmonic Content ◽  
Low Duty Cycle ◽  
Three Phase ◽  
Fft Analysis

This paper provides the operation and analysis of three phase two quadrant controlled converter. In this paper, the converter is being checked with varying the duty cycle for two different loads R and RL. The Power factor, Total Harmonic Distortion (THD) and efficiency are better for very low duty cycle which is the same for RL load. This analysis estimates THD and power factor at various conditions. The FFT analysis is done to find the harmonic content present in the input current waveform. This analysis is done using MATLAB software.

Why telehealth does not always save money for the health system

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Centaine L. Snoswell ◽  
Monica L. Taylor ◽  
Liam J. Caffery
Keyword(s):  
Health System ◽  
Data Extraction ◽  
Cost Savings ◽  
Cost Benefit ◽  
Cost Effective ◽  
Healthcare Services ◽  
Content Type ◽  
Frequency Of Contact ◽  
Traditional Service ◽  
Implementation Costs

PurposeThis study aims to determine elements of telehealth that have the potential to increase costs for the health system in the short to medium term.Design/methodology/approachA search of PubMed, EMBASE and Scopus databases was performed in May 2018 using broad terms for telehealth and economics. Articles were included if they identified and explained reasons for an increase in cost for telehealth services. Studies were categorised by economic analysis type for data extraction and descriptive synthesis.FindingsFourteen studies met inclusion criteria and were included in the review. These studies identified that increased health system costs were due to implementation costs (e.g. for equipment, software or staff training), increased use of other healthcare services (e.g. pharmaceutical services) and ongoing service costs (including staff salaries) resulting from telehealth being additive to traditional service (e.g. increased frequency of contact).Originality/valueTelehealth is often assumed to be a cost-effective method of delivering healthcare, even to the point where direct cost savings are expected by decision makers as a result of implementation. However, this investigation suggests it does not routinely reduce costs for the health system and can actually increase costs at both implementation and ongoing service delivery stages. Health services considering implementing telehealth should be motivated by benefits other than cost reduction such as improved accessibility, greater patient centricity and societal cost–benefit.

Study on Passivity-Based Control of TNPC PV Grid-Connected Inverter

2014 ◽  
Vol 571-572 ◽  
pp. 1000-1005
Author(s):  
Bai Le Zhang ◽  
Jiu He Wang ◽  
Feng Jiao Zhao
Keyword(s):  
Mathematical Model ◽  
Control Theory ◽  
Mathematical Models ◽  
Power Factor ◽  
Harmonic Distortion ◽  
Unity Power Factor ◽  
Simulation Results ◽  
Passivity Based Control ◽  
Grid Connected Inverter ◽  
Pv Grid

Euler-Lagrange (Euler-Lagrange, EL) mathematical model was established according to the topology of TNPC (T-type Neutral Point Clamped) PV grid-connected inverter. Based on the mathematical models and passivity-based control theory, the approach called injecting damping was adopted to design the passivity-based controller of the inverter. The passivity-based controller can decoupled-qaxis current at AC side of the grid and achieve unity power factor, the total harmonic distortion of grid-connected current is low, and the passivity-based controller also make the inverter have good dynamic and static performances. Simulation results show that the designed passive controller of TNPC PV grid-connected inverter is feasible.

scholarly journals Mathematical Driving Model of Three Phase, Two Level Inverter by (Method of Interconnected Subsystem)

2017 ◽  
Vol 13 (1) ◽  
pp. 73-82
Author(s):  
Mohammed Ali
Keyword(s):  
Power Quality ◽  
Power Factor ◽  
Harmonic Distortion ◽  
Industrial Applications ◽  
Ac Drives ◽  
Load Power ◽  
Ac Power ◽  
Three Phase ◽  
Driving Model ◽  
Mathematical Analyses

In this paper describe to mathematical analysis for a three-phase, two level inverter designs. As we know the power electronic devices (inverter) to convert the DC power to AC power (controller on output voltage and frequency level). In Industrial applications, the inverters are used for adjustable speed (AC Drives). In this paper, the mathematical analyses for inverter design are done by using Software packages C++ Builder and visual C++ Language. For non- linear distortions described by the load power factor in power system networks. The P.F is reverse proportional with the harmonics distortion. Small P.F means much more of harmonic distortion, and lower power quality for consumers. to improve the P.F, and power quality in this paper the small capacitor installed as part of the rectified the load current has power (30 KW with P.F load 0.8), the fluctuations of the rectified voltage must not greater than +/- 10%.The power factor proportion of the load power, with Modulation coefficient p.u approximately unity. The calculation is achieved with different integrations steps with load power 30KW, 0.8 P.F. all results done Based on model and experimental data.

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