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Article
Publication date: 1 October 2006

İres İskender, Yıldürüm Üçtug˘ and H. Bülent Ertan

To derive an analytical model for a dc‐ac‐dc parallel resonant converter operating in lagging power factor mode based on the steady‐state operation conditions and considering the…

Abstract

Purpose

To derive an analytical model for a dc‐ac‐dc parallel resonant converter operating in lagging power factor mode based on the steady‐state operation conditions and considering the effects of a high‐frequency transformer.

Design/methodology/approach

A range of published works relevant to dc‐ac‐dc converters and their control methods based on pulse‐width‐modulation technique are evaluated and their limitations in output measurement of higher output voltage converters are indicated. The circuit diagram of the converter is described and the general mathematical model of the system is obtained by deriving and combining the mathematical models of the different converter blocks existing in the system. The derived mathematical model is used to study the steady‐state and transient performance of the converter. The deriving procedure of the analytical model for a parallel resonant converter is extensively given and the analytical model obtained is verified by simulation results achieved using MATLAB/SIMULINK and the program written by the authors.

Findings

The paper suggests an analytical model for dc‐ac‐dc parallel resonant converters. The model can be used in the output voltage estimation of a converter in terms of its phase‐shift angle and the dc‐link voltage.

Research limitations/implications

The resources in the library of the authors' university and also the English resources relative to dc‐ac‐dc converters reachable through the internet were researched.

Practical implications

The analytical model suggested can be used in estimating the output voltage of the converters used in high‐voltage applications or where there are difficulties in employing sensors in measurement of the output voltage due to high price or implementation problems.

Originality/value

The originality of the paper is to present an analytical model for dc‐ac‐dc parallel resonant converters. Using this model makes it possible to estimate the output voltage of the converter using the dc‐link voltage and the phase‐shift angle. The proposed model provides researchers to regulate the output voltage of the converters using feed‐forward control technique.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 10 September 2018

Yuvaraja T. and K. Ramya

The purpose of studying the low voltage direct current (DC) microgrid, which uses computerised control system techniques, an orderly coordination control stratagem considering…

Abstract

Purpose

The purpose of studying the low voltage direct current (DC) microgrid, which uses computerised control system techniques, an orderly coordination control stratagem considering optimisation of a hybrid energy storage system (HESS) was projected in this paper.

Design/methodology/approach

The projected control stratagem was divided into three levels: topmost power dispatch level, transitional bus voltage regulation level and bottommost converter control level.

Findings

At the topmost power dispatch level, the cost of system stability was introduced, which is related with state of charge and discharging power of HESS.

Originality/value

Furthermore, the cost of system stability and HESS depreciation was compared with commercial price, and HESS switches its operating mode to discharge more at higher price or charge more at lower price to ensure the DC microgrid in economic operation. At the transitional bus voltage regulation level, DC bus gesturing is used as a control signal to achieve an autonomous decentralised operation of DC microgrid. The Matlab/Simulink simulation inveterate that the economical and autonomous decentralised operation can be achieved through the control stratagem.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 6
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 10 February 2023

Kanungo Barada Mohanty and Pavankumar Daramukkala

The purpose of this study is to provide the enhancement of power quality of a high power-rated voltage source inverter driven induction motor with a three-phase, three-level…

Abstract

Purpose

The purpose of this study is to provide the enhancement of power quality of a high power-rated voltage source inverter driven induction motor with a three-phase, three-level neutral point clamped converter placed at the front end, while a passive power filter is connected in shunt with it. The improvement in power quality can be achieved by reducing the total harmonic distortion in source current. The controllers were designed for the linearization of the high-power induction motor drive. A control method is presented for the regulation of the common DC-link voltage.

Design/methodology/approach

The induction motor is modeled using its dynamic equations, and a decoupling controller is designed to linearize the nonlinear dynamics of the drive through feedback. The common DC-link voltage of the proposed front-end connected converter is monitored and controlled through a control method which feeds the pulse width modulated inverter that drives the induction motor. A passive power filter is designed to meet the reactive power requirement of the system in addition to improve the power quality.

Findings

Simulations were carried out for the proposed topology of the drive mechanism, and the outcomes were analyzed by a comparative analysis of the drive system both in the presence of the passive filter as well as in the absence of the filter. The total harmonic distortion is found to be reduced enough to meet the standards with the designed filter, and the reactive power is also compensated considerably. The input power factor at the supply side is maintained almost to unity, and the DC-link voltage of the proposed circuit topology is maintained at the desired level. The overall performance of the drive system was found to be useful and economical.

Originality/value

A new topology of a front-end connected three-level neutral point clamped converter to a high power-rated induction motor drive is proposed. The drive is fed by a pulse width modulated inverter with a common DC-link with the front end connected converter. A passive filter is designed with respect to the reactive power requirement of the system and connected in shunt to the converter at the supply side. Control schemes are designed and used for the drive system and also for the regulation of the common DC-link voltage of the proposed front end connected converter.

Details

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

Keywords

Article
Publication date: 5 August 2022

Dharma Raj T., Kumar C., Subramaniam G., Dhanesh Raj T. and Jasper J.

Renewable energy sources such as solar photovoltaic (PV) and wind are ubiquitous because of their lower environmental impact. Output from solar PV and wind turbines is unstable;…

Abstract

Purpose

Renewable energy sources such as solar photovoltaic (PV) and wind are ubiquitous because of their lower environmental impact. Output from solar PV and wind turbines is unstable; hence, this article aims to propose an effective controller to extract maximum available power.

Design/methodology/approach

By focusing on the varying nature of solar irradiance and wind speed, the paper presents the maximum power point tracking (MPPT) technique for renewable energy sources, and power regulation is made by the novel inverter design. Moreover, a DC–DC boost converter is adopted with solar PV, and a doubly fed induction generator is connected with the wind turbine. The proposed MPPT technique is used with the help of a rain optimization algorithm (ROA) based on bi-directional long short-term memory (Bi-LSTM) (ROA_Bi-LSTM). In addition, the sinusoidal pulse width modulation inverter is used for DC–AC power conversion.

Findings

The proposed MPPT technique has jointly tracked the maximum power from solar PV and wind under varying climatic conditions. The power flow to the transmission line is stabilized to protect the load devices from unregulated frequency and voltage deviations. The power to the smart grid is regulated by three-level sinusoidal pulse width modulation inverter.

Originality/value

The methodology and concept of the paper are taken by the author on their own. They have not taken a duplicate copy of any other research article.

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) converters

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

Keywords

Article
Publication date: 3 May 2013

Hong Li, Fei Lin, Zhong Li, Xiajie You, Trillion Q. Zheng and Bo Zhang

Four‐quadrant AC‐DC converters are one kind of the most common and popular AC‐DC converters, which are serious EMI sources. The purpose of this paper is to propose a novel control…

Abstract

Purpose

Four‐quadrant AC‐DC converters are one kind of the most common and popular AC‐DC converters, which are serious EMI sources. The purpose of this paper is to propose a novel control for four‐quadrant AC‐DC converters to suppress the generated electromagnetic interference (EMI).

Design/methodology/approach

A chaotic carrier plays an important role to implement the chaotic PWM control. The relationship between the EMI distribution and carrier frequency is given by deducing and analyzing the harmonic components of the AC‐DC converter. The comparison of chaotic PWM control and random PWM control in suppressing EMI are provided.

Findings

The simulation results prove the effectiveness of the proposed chaotic PWM control on EMI reduction.

Research limitations/implications

The effects of EMI suppression under different chaotic carriers will be theoretically analyzed in the future work.

Practical implications

The proposed chaotic PWM control can suppress EMI for converters without adding additional devices or components, therefore, without increasing the volume, weight and cost of converters.

Originality/value

In this paper, a novel chaotic pulse width modulation (PWM) control is proposed and implemented into a four‐quadrant AC‐DC converter for electromagnetic interference (EMI) suppression, moreover, the total harmonic distortion (THD) of the input AC current is also improved under chaotic PWM control.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 4 January 2011

Szymon Piasecki, Marek Jasiński and Aritz Milicua

The purpose of this paper is to consider both sides of a back‐to‐back AC‐DC‐AC interface.

Abstract

Purpose

The purpose of this paper is to consider both sides of a back‐to‐back AC‐DC‐AC interface.

Design/methodology/approach

The paper presents a mathematical analysis, simulation, laboratory test in scaled model.

Findings

The two main findings comprised concept of control methods for grid AC‐DC‐AC converter applied in renewable energy sources with variable speed operation under distorted grid. Active filtering functionality in case of non‐linear current of a parallel load. Second, a control algorithm dedicated for two‐level AC‐DC converter applied in industrial networks with high‐order harmonics compensation working under hard conditions – balanced and unbalanced voltage dips.

Research limitations/implications

The paper shows preliminary results for AC‐DC‐AC converter and active filter (AF) during voltage dips and for harmonics compensation. Control methods and/or topology should be improved and tested in scale and after at high‐power system.

Practical implications

Power quality supplied/received to/from the grid can be increased. In case of low‐cost system only AF can be applied to existing non‐linear receivers. Moreover, in case of full AC‐DC‐AC converter energy saving and production is possible.

Originality/value

Presented control methods give satisfactory results. Paper presents laboratory results for grid and machine side two different power circuits during steady states and transients. Moreover, active filtering operation during voltage dips is presented.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 January 2006

Marek Jasinski, Mariusz Cichowlas and Marian P. Kazmierkowski

Proposes the application of novel control strategy in power transistors (insulated gate bipolar transistors – IGBT) based on AC/DC/AC converter with active filtering function…

1474

Abstract

Purpose

Proposes the application of novel control strategy in power transistors (insulated gate bipolar transistors – IGBT) based on AC/DC/AC converter with active filtering function. Seeks to investigate the possibilities of operating drive system under distorted line voltage with unity power factor and reduced dc‐link capacitor.

Design/methodology/approach

A novel control strategy is proposed based on direct power and direct torque control with space vectors modulators scheme which seems to be most promising. This method is investigated, implemented and examined in the laboratory setup. Different working conditions are taken into consideration.

Findings

Provides information how the proposed system works under motoring and regenerating modes. Good behaviors of the system in steady state in transience are shown. Very good stabilization of the dc‐link voltage under transient is achieved. Almost sinusoidal line current is obtained. Very good compensation of nonlinear load is also achieved.

Research limitations/implications

This is not an exhaustive investigation. The system should be tested with different input inductances (or LCL filters) and with reduced dc‐link capacitor. Moreover, laboratory tests with higher power should be performed in the future.

Practical implications

A useful source of information and an example of how a fully controlled AC/DC/AC converter with active filtering function works. It could be an important basis for a prototype for industry.

Originality/value

Although the direct power control with space vector modulator (DPC‐SVM) and direct torque control with space vector modulator (DTC‐SVM) schemes have been described in the literature separately, it is analyzed for the first time and investigated together for control of the AC/DC/AC converter. Additionally, active filtering provides a feature of power compensation. It could be the basis for a clean power system design.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 October 2006

İres İskender, Yıldırım Üçtuğ and H.Bülent Ertan

To analyze the operating performance of an ac‐dcac‐dc PWM parallel resonant converter operating at lagging power factor mode controlled based on fuzzy logic control method.

1339

Abstract

Purpose

To analyze the operating performance of an ac‐dcac‐dc PWM parallel resonant converter operating at lagging power factor mode controlled based on fuzzy logic control method.

Design/methodology/approach

A range of published works relevant to dc‐ac‐dc converters and their control methods based on PWM technique are evaluated and their limitations in converter output voltage control are indicated in the first section of this paper. The Simulink model and different stages of the converter are described in the second section. In Section 3, the general mathematical model of the system is derived and the phase‐shift PWM switching technique is explained. The equivalent circuit of the high‐voltage high‐frequency transformer used in the converter and the effects of the transformer parameters on the converter operation are presented in Section 4. In Section 5, fuzzy logic control and the basic concepts of this method are described and its application to the proposed converter output voltage control is explained. In Section 6, the Simulink simulation results of the fuzzy logic control application are given for different operating conditions. In Section 7, an overview of the hardware used in this study is presented and the experimental results are given to show the performance of the controller. Finally, Section 8 gives the conclusions of the study.

Findings

The fuzzy logic control which is a suitable method for nonlinear systems such as the converter proposed in this paper, is successfully applied for output voltage control of the converter. The controller performance is satisfied. The phase‐shift angle of the converter is used as the control parameter. The paper also presents how the parasitic parameters of the transformer used in high‐voltage applications can be used as the circuit resonant elements.

Research limitations/implications

In preparing this paper, the resources books and periodic journals existing in our university library and also the English resources relative to dc‐ac‐dc converters reachable through the internet were researched.

Practical implications

The suggested control method can be used in the control of linear and nonlinear systems. The study carried out in this paper is also a very good approach to be used in high‐voltage high‐frequency converters output voltage control.

Originality/value

Since, the control approach proposed in this paper does not require the information on converter and transformer parameters that affect the converter output voltage, so it can effectively be used in applications where there are parameter variation problems. The design of the transformer for the required load, finding an optimum operating frequency for the converter, and using the transformer parameters as resonant elements of the circuit to decrease the switching losses are the other contributions of this paper.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 8 February 2021

Saravanan R., Vijayshankar S., Sathyaseelan and Suresh K.

This paper aims to propose Hidden Converter (H-Converter) combined with dual port 3Ø inverter for energy storage application to produce wide range of voltage. Some of the…

Abstract

Purpose

This paper aims to propose Hidden Converter (H-Converter) combined with dual port 3Ø inverter for energy storage application to produce wide range of voltage. Some of the application required wide range of voltages, but problem from E-chopper is either boost or buck mode of operations, both modes are not possible. To overcome this drawback, H-Converter is combined with dual port 3Ø inverter controlled by carrier-based pulse width modulation (CB-PWM) technique is added with zero sequence injection.

Design/methodology/approach

Hidden converter is a bidirectional DC-DC chopper used to convert fixed DC to variable DC and vice versa in both buck and boost modes of operations. Dual port inverter is combined with hidden DC-DC converter can produce wide range of voltages.

Findings

The bidirectional DC-AC converter requires less power for processing and consumes less power losses by using modest carrier built- pulse width modulation scheme through proposed zero structure addition.

Originality/value

By using this proposed strategy H-Converter can produce wide range of voltage in both the sides and mostly power is processed in the 3Ø inverter with a one stage conversion with less power loss. As a result, with one stage power conversion has more efficiency because of less power loss. This proposed converter has designed by analysis, and the real time result is tested in an experiment.

Details

Circuit World, vol. 48 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

1 – 10 of 137