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Article
Publication date: 5 May 2020

Congliang Fei, Pengfei Xiahou and Fujun Wang

This study aims to focus on the grid connected inverter.

Abstract

Purpose

This study aims to focus on the grid connected inverter.

Design/methodology/approach

The grid connected inverter for harmonic suppression was designed, the topological structure of the inverter and the design of LCL filter were analyzed, then a PIR controller was proposed and finally simulation and experiment were carried out.

Findings

The simulation results showed that the distortion rates of the 5th, 7th and 11th harmonics under PIR control were 0.14%, 0.13% and 0.06%, respectively, which were significantly lower than that under PI control. The system test results also showed that the current waveform under PI control was rough and total harmonic distortion (THD) content was 3.8%; under PIR control, the grid connected current waveform was relatively smooth, with fewer spikes and burrs, and the THD content was 1.9%, indicating that the harmonics were effectively suppressed.

Originality/value

The experimental results verify that the inverter and PIR controller designed in this study are effective for harmonic suppression. This work makes some contributions to the improvement of the effect of harmonic suppression and promotion of the better application of grid connected inverter.

Details

Journal of Engineering, Design and Technology , vol. 18 no. 5
Type: Research Article
ISSN: 1726-0531

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Article
Publication date: 8 March 2021

Rohollah Abdollahi

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…

Abstract

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.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 6 August 2018

Rohollah Abdollahi

For direct torque controlled induction motor drives, an effective solution to eliminate harmonics is the use of multipulse alternating current (AC)-direct current (DC…

Abstract

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.

Details

World Journal of Engineering, vol. 15 no. 4
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 31 January 2020

Subhendu Bikash Santra and Subodh Kumar Mohanty

The purpose of this study is to present a new methodology of selective harmonics elimination (SHE) technique suitable for single-phase photovoltaic (PV) tied pulse width…

Abstract

Purpose

The purpose of this study is to present a new methodology of selective harmonics elimination (SHE) technique suitable for single-phase photovoltaic (PV) tied pulse width modulated (PWM) inverter.

Design/methodology/approach

In the proposed SHE, switching angles for inverter control are determined offline through numerical techniques and stored in a microcontroller memory as a function of modulation index (md). The methodology uses the solution that leads to a lower change of switching angles from the previous modulation index (md) for storing in the processor memory for multiple solutions. This leads to a smaller number of sections when a piecewise mixed model is considered for storing the entire switching angle curve for the online inverter control. The proposed idea is simulated and experimentally validated on a laboratory prototype of PV (500 W) grid-tied PWM inverter. The control environment is then realized in NI c-RIO 9082.

Findings

This proposed technique is suitable for limiting voltage total harmonics distortion (THD) in single-phase PV tied grid connected voltage source inverter (VSI). Moreover, it is found that filter (L-C) size requirement is less.

Originality/value

The proposed SHE with piecewise mixed model technique effectively reduces voltage THD with less filter size (L-C) in a single-phase PV-tied system.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 39 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 6 February 2007

Antonio Moreno‐Muñoz, Mª Dolores Redel, Daniel Oterino and Juan J.G. De la Rosa

The purpose of this paper is to address the issue of power quality through a case study in an IT‐intensive modern office building.

Abstract

Purpose

The purpose of this paper is to address the issue of power quality through a case study in an IT‐intensive modern office building.

Design/methodology/approach

This paper presents results from a power quality audit conducted last year. Firstly, the power site inspection included: (a) a walk‐down of the facility's electrical system to inspect the condition of equipment and becoming familiar with the electrical system; (b) interviewing facility electrical personnel and end‐users on failure of equipment; (c) identifying and collecting the electronic equipment that is most sensitive to power disturbances; (d) requesting and reviewing equipment literature and electromagnetic compatibility characteristics; (e) after that, in the power quality monitoring, voltage and current were measured at various floors.

Findings

It was found that the main problems for the equipment installed were harmonics and leakage currents. The paper examines the causes and effects of power disturbances that affect computer or any other microprocessor based equipment and analyses the disadvantages of modern power supplies.

Practical implications

This provides useful information for facilities managers on the current state of power disturbances. The convenience of “enhanced power supply” is also discussed. Finally, it is addressed the role of standards on the protection of IT and the implications for the final costumer.

Originality/value

This paper has provided empirical data from a power site survey developed in a high tech building. This case study demonstrates the impacts of generalized electronic devices on the power quality of the buildings and the implications on energy uses.

Details

Facilities, vol. 25 no. 1/2
Type: Research Article
ISSN: 0263-2772

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Article
Publication date: 8 November 2019

Mohsen Karimi, Mohammad Pichan, Mehdi Sadri and Seyed Morteza Seyedjafari

This paper aims to investigate an improved control method and digital signal processor-based (DSP-based) digital implementation of three-phase standalone inverter. The…

Abstract

Purpose

This paper aims to investigate an improved control method and digital signal processor-based (DSP-based) digital implementation of three-phase standalone inverter. The proposed method is performance developed of the proportional-resonant controller (PRC) with harmonic injection technique, aiming to improve load voltages quality under different loads, especially nonlinear loads. The advanced proposed multi-loop controller is consisted of current harmonic loops for suppressing odd harmonic, which are analyzed in discrete-time domain. Besides, the voltage loop is also used to compensate the output capacitor voltage.

Design/methodology/approach

The proposed method can effectively enlarge output voltage stability with low total harmonics distortion and improve the dynamic transient response. The other advantage of the proposed PRC is the injection of the selective harmonic without any additional calculation compensator.

Findings

The method is given the opportunity to be controlled exactly all harmful outputs with high-quality voltage referenced of the standalone inverter. The proposed method is implemented using a DSP processor (TMS320F28335) and is verified on the 10 kVA three-phase standalone inverter prototype.

Originality/value

The proposed method is performance developed of the PRC with harmonic injection technique, aiming to improve load voltages quality under different loads, especially nonlinear loads.

Details

World Journal of Engineering, vol. 16 no. 6
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 5 January 2015

Hernaldo Saldías Molina, Juan Dixon Rojas and Luis Morán Tamayo

The purpose of this paper is to implement a finite set model predictive control algorithm to a shunt (or parallel), multilevel (cascaded H-bridge) active power filter…

Abstract

Purpose

The purpose of this paper is to implement a finite set model predictive control algorithm to a shunt (or parallel), multilevel (cascaded H-bridge) active power filter (APF). Specifically, the purpose is to get a controller that could compensate the mains current and, at the same time, to control the voltages of its capacitors. This strategy avoids the use of multiple PWM carriers or another type of special modulator, and requires a relatively low processing power.

Design/methodology/approach

This paper is focussed in the application of the predictive controller to a single-phase parallel APF composed for two H-bridges connected in series. The same methodology can be applied to a three-phase APF. In the DC buses of each H-bridge, a floating capacitor was connected, whose voltage is regulated by the predictive controller. The controller is composed by, first, a model for the charge/discharge dynamics for each floating capacitor and a model for the output current of the APF; second, a cost function; and third, an optimization algorithm that is able to control all these variables at the same time, choosing in each sample period the best combination of firing pulses.

Findings

The controller can track the voltage references, compensate the current harmonics and compensate reactive power with an algorithm that evaluates only the three nearest voltage levels to the last voltage level applied in the inverter. This strategy decreases the number of calculations required by the predictive algorithm. This controller can be applied to the general case of a single-phase multilevel APF of N-levels and extend it to the three-phase case without major problems.

Research limitations/implications

The implemented controller, when the authors consider a constant sample time, gives a mains current with a Total Harmonic Distortion (THD-I) slightly greater in comparison with the base algorithm (that evaluates all the voltage levels). However, when the authors consider the processing times under the same processor, the implemented algorithm requires less time to get the optimal values, can get lower sampling times and then a best performance in terms of THD-I. To implement the controller in a three-phase APF, a faster Digital Signal Processor would be required.

Originality/value

The implemented solution uses a model for the charge/discharge of the capacitors and for the filter current that enable to operate the cascaded multilevel inverter with asymmetrical voltages while compensates the mains currents, with a predictive algorithm that requires a relatively low amount of calculations.

Details

COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering, vol. 34 no. 1
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 20 June 2020

Fossy Mary Chacko, Ginu Ann George, Jayan M.V. and Prince A.

This paper aims to propose an improved multifunctional control strategy for achieving real, reactive power flow control and the mitigation of power quality issues in grid…

Abstract

Purpose

This paper aims to propose an improved multifunctional control strategy for achieving real, reactive power flow control and the mitigation of power quality issues in grid integrated photovoltaic (GIPV) systems.

Design/methodology/approach

The paper proposes a dual stage, three phase, multifunctional GIPV system with modified instantaneous reactive power (IRP) theory-based and modified synchronous reference frame (SRF) theory-based control algorithms for reference template generation with continuous load power requirement tracking. The control structure is designed so as to impart virtual distribution static compensator functionality to the photovoltaic inverter. The dual mode operation in active filter and renewable power injection modes provides enhanced capability to the GIPV system. A comprehensive evaluation of the dynamic behaviour of the GIPV system is carried out for various conditions of irradiance and load under MATLAB/Simulink platform. The performance comparison is done considering an uncompensated system and the GIPV system with both proposed control algorithms.

Findings

The extensive simulation results demonstrate that the proposed modified SRF theory-based multifunctional control strategy shows superior performance in real and reactive power flow control; reduction in real and reactive burden of the utility grid; and regulation of dc bus voltage under varying scenarios of irradiance and load. Furthermore, there is improvement of grid power factor and reduction in total harmonic distortion of grid currents in compliance with the IEEE 519 standard even with highly non-linear loads at the point of common coupling.

Originality/value

The proposed modified SRF theory-based multifunctional controller offers a viable solution for power quality enhancement as well as the realization of effective real and reactive power flow control in GIPV systems. Thus, the penetration level of distributed generation can be increased in this era of global energy crisis.

Details

World Journal of Engineering, vol. 17 no. 4
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 24 September 2020

Kannan Chandrasekaran, Nalin Kant Mohanty and Selvarasu Ranganathan

Multilevel inverter (MLI) is a prevailing sensible alternative to two-level inverters that offer a high-quality output voltage waveform, wherein the multiple input direct…

Abstract

Purpose

Multilevel inverter (MLI) is a prevailing sensible alternative to two-level inverters that offer a high-quality output voltage waveform, wherein the multiple input direct current (DC) levels are established by using isolated DC sources, batteries and renewable energy sources. The purpose of this paper is to develop MLI to offer lower total harmonic distortion (THD), higher output voltage levels and reduced switching components for high power applications.

Design/methodology/approach

In this paper, a new tapped sources stack succored modified HX bridge MLI (TSSSMHXBMLI) topology is proposed which includes two modules, such as tapped sources stack (TSS) and modified HX bridge inverter, which perform their function in a single stage. Also, this paper outlines the formulaic implementation of the multicarrier/sub-harmonic pulse width modulation (MCPWM/SHPWM) in a Xilinx Spartan3E-500 field programmable gate array (FPGA) is suitable for the developed MLI.

Findings

The feasibility of the suggested topology is well proved by both simulation and experiment results.

Practical implications

This paper examines a new topology of TSSSMHXBMLI with a view to minimize total count of switching components against basic MLI topologies. The operating sequence of the suggested TSSSMHXBMLI topology is verified with the simulation study followed by an experimental investigation.

Originality/value

The simulation and experimental results of suggested MLI topology reveals to obtain lower THD, higher output voltage levels and reduced switching components for high power applications.

Details

Circuit World, vol. 47 no. 2
Type: Research Article
ISSN: 0305-6120

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Article
Publication date: 9 August 2021

Md Tariquzzaman, Md Habibullah and Amit Kumer Podder

Maintaining a balanced neutral point, reducing power loss, execution time are important criteria for the controlling of neutral point clamped (NPC) inverter. However, it…

Abstract

Purpose

Maintaining a balanced neutral point, reducing power loss, execution time are important criteria for the controlling of neutral point clamped (NPC) inverter. However, it is tough to meet all the challenges and also supplying the load current within the harmonic limit. This paper aims to maintain load current quality within the Institute of Electrical and Electronics Engineers 519 standard and meet the above-mentioned challenges.

Design/methodology/approach

The output load current of a three-level simplified neutral point clamped (3 L-SNPC) inverter is controlled in this paper using model predictive control (MPC). The 3 L-SNPC inverters is considered because fewer semiconductor devices are used in this topology; this will enhance the reliability of the system. MPC is used as a controller because it can handle the direct current-link capacitors’ voltage balancing problem in a very intuitive way. The proposed 3 L-SNPC yields similar current total harmonic distortion (THD), transient and steady-state responses, voltage stress and over current protection capability as the conventional NPC inverter. To reduce the computational burden of the proposed SNPC system, two simplified MPC strategies are proposed, namely, single voltage vector prediction-based MPC and selective voltage vector prediction-based MPC.

Findings

The system shows a current THD of 2.33% at 8.96 kHz. The overall loss of the system is reduced significantly to be useful in medium power applications. The required execution times for the simplified MPC strategies are tested on the hardware dSPACE 1104 platform. It is found that the single voltage vector prediction-based MPC and the selective voltage vector prediction-based MPC are computationally efficient by 8.28% and 62.9%, respectively, in comparison with the conventional MPC-based conventional NPC system.

Originality/value

Multiple system constraints are considered throughout the paper and also compare the SNPC to the conventional NPC inverter. Proper current tracking, over-current protection, overall power loss reduction especially switching loss and maintaining capacitor voltages balance at a neutral point are achieved. The improvement of execution time has also been verified and calculated using hardware-in-loop of the dSPACE DS1104 platform.

Details

World Journal of Engineering, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1708-5284

Keywords

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