Omar Abdel-Rahim | Aswan University (original) (raw)

Papers by Omar Abdel-Rahim

Energies, Dec 1, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

2022 IEEE 63th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)

Energies

High penetration of renewable energy sources into isolated microgrids (µGs) is considered a criti... more High penetration of renewable energy sources into isolated microgrids (µGs) is considered a critical challenge, as µGs’ operation at low inertia results in frequency stability problems. To solve this challenge, virtual inertia control based on an energy storage system is applied to enhance the inertia and damping properties of the µG. On the other hand, utilization of a phase-locked loop (PLL) is indispensable for measuring system frequency; however, its dynamics, such as measurement delay and noise generation, cause extra deterioration of frequency stability. In this paper, to improve µG frequency stability and minimize the impact of PLL dynamics, a new optimal frequency control technique is proposed. A whale optimization algorithm is used to enhance the virtual inertia control loop by optimizing the parameters of the virtual inertia controller with consideration of PLL dynamics and the uncertainties of system inertia. The proposed controller has been validated through comparisons ...

IEEE Access, 2022

PV systems are penetrating the energy generation market rapidly. PV system output strongly depend... more PV systems are penetrating the energy generation market rapidly. PV system output strongly depends on environmental conditions. As a result, the utilization of power electronic converters is mandatory. On the other hand, most modern loads, from small to big ones, are based on dc, similar to the renewable sources generating dc. Hence, wide adoption of residential dc microgrids (RDCμGs) based on PV energy would be a trend soon, following modern developments in energy-efficient buildings. This paper targets power converters for the integration of PV systems into RDCμGs. It considers two main classes: high stepup converters for PV module-level, parallel optimizer, applications, and non-isolated buck-boost converters for the PV string, series optimizer, applications. Due to the importance of the PV topic, a significant number of topologies have been introduced in the literature. However, not all topologies attracted the interest of the industry. This review paper considers PV converters used in industry or demonstrated in academia at a high technology readiness level with comprehensive experimental justification. This allows us to focus this review on the most valuable solutions and to provide a guide for both industry and academic readers. In the end, future trends in industrial PV systems and power converters are discussed.

IEEE Access

The converter efficiency defines the overall efficiency of a renewable energy system. In a full p... more The converter efficiency defines the overall efficiency of a renewable energy system. In a full power converter, its components process the whole input power, even if it is not mandatory. Partial power processing (PPP) is an exciting concept for improving overall system efficiency and reducing system cost and size. In PPP, the converter processes the amount of power needed to be processed. This work proposes a PPP based on the high-performance Quasi-Z-Source Series Resonance converter (QZSSRC). The proposed partial power converter has a series-input parallel-output (SIPO) architecture. Previous publications in this area mainly consider converters with step-down voltage regulation, like the phase-shifted full-bridge converter. They underperform in this application due to operating at the maximum power when bucking the voltage the most. This paper studies two other types of dc-dc converters, buck-boost and boost, in SIPO partial power converters. Theoretical operation principles are corroborated with full experimental results given and analyzed. A 300 W prototype of the QZSSRC is used to convert the power of up to 2 kW in a PPP system with overall system efficiency over 99%. INDEX TERMS Power converters, partial power processing (PPP), quasi Z-source series resonance converter (QZSSRC), step up, step down, efficiency.

2019 International Conference on Innovative Trends in Computer Engineering (ITCE)

current source inverter (CSI) requires particular modulation strategy due to its configuration an... more current source inverter (CSI) requires particular modulation strategy due to its configuration and principle of operation. An overlap period of time between the switching states is necessary so as not to cut the input inductor current. When operated by space vector pulse width modulation (SVPWM), this overlap instant results in current harmonic distortions. The current distortions deteriorates the quality of electric power delivered by CSI. The following paper introduces a comparative study between five and seven segment modulation sequences of SVPWM, and investigates their effect on the current distortions resulted by the overlap instant. The study finally recommends one modulation sequence over the other to alleviate the impact of the overlap instant on the output current waveform.

2022 IEEE 13th International Symposium on Power Electronics for Distributed Generation Systems (PEDG)

2022 IEEE 7th International Energy Conference (ENERGYCON)

2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE)

Micro-inverters recently become more attractive due to its modularity and independent maximum pow... more Micro-inverters recently become more attractive due to its modularity and independent maximum power point tracking for each individual photovoltaic (PV) module. Micro-Inverters designed for PV applications requires to perform different tasks such as extracting maximum power from PV, boost low PV voltage to a higher level and convert DC-voltage into AC voltage. Typically, a Micro-Inverter consists of two stages; a DC-DC Converter and DC-AC Inverter. This paper proposed a novel two-stage micro-inverter based on LLC resonant converter for grid integrated PV system. LLC resonant converter is presented as a first stage for the PV micro-inverter. and the second stage implemented from the three-phase inverter. The selection of the LLC resonant converter comes from its inherent features such as high efficiency converter for a wide range of input voltage and load variation, due to its capability to work under soft switching techniques like Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS), possibility of achieving high voltage gain due to the presence of the HF transformer achieved. A complete feedback system is implemented in order to control maximum power of PV panel, maintain a fixed DC link voltage, and inject a sinusoidal current injected into the grid. The results have been validated by simulation and experimental topology vai OPAL-RT OP4510

Energies

In this article, a new non-inverting buck-boost converter with superior characteristics in both b... more In this article, a new non-inverting buck-boost converter with superior characteristics in both bucking and boosting is presented. The proposed converter has some distinct features, such as high step-up/-down ability and low voltage/current stress on its switching devices. The voltage gain of the proposed converter is double the reported value for the traditional buck-boost converter. Although it has three switches, the three switches operate simultaneously, hence no dead-time is required. Two out of the three switches are under voltage stress equal to half of the output voltage. The overall efficiency of the system is promising because of the ability to select devices with low voltage drops. Converter analysis and steady-state performance in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are presented in detail. A 1 kW hardware prototype of the converter was implemented in the laboratory; with a step-up ratio of 3.5 and 1 kW power, the measured effici...

Frontiers in Energy Research

Due to the low voltage of the PV module and to enable AC module technology, where every PV module... more Due to the low voltage of the PV module and to enable AC module technology, where every PV module has its own DC-AC converter, this paper introduces a new high step-up seven-level two-stage multilevel inverter for a grid-connected Photovoltaic (PV) system. The introduced schematic consists of two stages. The first stage is a switched capacitor boost converter and the second stage is a seven-level seven-switches multilevel inverter. The first stage is designed to extract the maximum power of PV module and step-up its input voltage. The proposed seven-level seven-switches topology generates seven levels with only seven switches. Thus, the number of switches is reduced. The proposed inverter has eight valid switching states. In each switching state only three switches are ON at the same time. The proposed topology has some distinct features such as reduced number of switches and reduced conduction; total harmonic distortion (THD) of the current is 23% in case of pure resistive and with...

2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe), 2016

This paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) app... more This paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) applications. The proposed system has distinct feature such as: high voltage gain, high efficiency, low voltage stress and galvanic isolation. The system is controlled via Model Predictive Control (MPC) to do the following functions: extract maximum power from the PV generator, and inject a sinusoidal current into the utility with unity power factor.

Journal of Electrical Engineering & Technology, 2017

– We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set... more – We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

Electronics, 2022

This article proposes a new high-gain transformerless dc/dc boost converter. Although they posses... more This article proposes a new high-gain transformerless dc/dc boost converter. Although they possess the ability to boost voltage at higher voltage levels, converter switching devices are under low voltage stress. The voltage stress on active switching devices is lower than the output voltage. Therefore, low-rated components are used to implement the converter. The proposed converter can be considered as a promising candidate for PV microconverter applications, where high voltage-gain is required. The principle of operation and the steady-state analysis of the converter in the continuous conduction mode are presented. A hardware prototype for the converter is implemented in the laboratory to prove the concept of operation.

2019 21st International Middle East Power Systems Conference (MEPCON), 2019

Direct Matrix Converter (DMC) is superior topology for AC/AC power transformation. Its superiorit... more Direct Matrix Converter (DMC) is superior topology for AC/AC power transformation. Its superiority comes from its inherent advantages such as: small size, no electrolytic capacitors, and straight conversion ability. Multiphase machines, would be the future trend in high power applications due to their features; better torque concentration, less torque pulsations, and superior fault tolerance. This paper introduces the usage of five-phase Induction Motor (IM). For that purpose, a three-to-five DMC is required to drive the five-phase induction motor without affecting the existing three-phase system. An improved Model-Predictive Torque Control (MPTC) is presented in this paper to regulate the toque and the speed of the five-phase induction motor. a 15 kW five-phase IM is simulated using MATLAB platform. The functionality of the closed loop system confirms the strength and robustness of the anticipated technique.

SVU-International Journal of Engineering Sciences and Applications, 2021

In this article, a new high gain dc/dc converter is proposed that can be used with applications t... more In this article, a new high gain dc/dc converter is proposed that can be used with applications that require elevating output voltage to higher voltage-level such as PV applications. The proposed configuration is able to achieve high-voltage-gain, compared to any other transformerless topologies. The voltage stresses on the active MOSFETs are lower than half of the output voltage. Hence, low rated components are selected. The principles of operation of the two configurations are analyzed in details. Hardware prototype is implemented in the lab, in order to verify the analytical analysis of the topology.

2019 IEEE Applied Power Electronics Conference and Exposition (APEC), 2019

Usually, power converters are used to deliver renewable energy to the grid. The operation of thes... more Usually, power converters are used to deliver renewable energy to the grid. The operation of these converters greatly impacts the power quality and reliability of the power system. Hence, more attention should be paid to the performance of such power electronic systems. Being one of these converters, current source inverter (CSI) operation is influenced by the overlap period (OLP) that is included in its pulse-train to prevent voltage spikes. The OLP results in waveform distortions and vector deviation error. This study proposes an overlap technique and optimizes the modulation sequence that reduced the effect of OLP remarkably. The ampere-second analysis of the dwell times of the modulation vectors is provided, the resulted error expressions are derived. Hardware prototype is being implemented in the lab and a sample of the results are provided.

2016 19th International Conference on Electrical Machines and Systems (ICEMS), 2016

Dc structures are acquisitioning acceptance owing to its high efficiency, high reliability and ea... more Dc structures are acquisitioning acceptance owing to its high efficiency, high reliability and easy interconnection of renewable sources as compared to ac systems. In standalone dc system, parallel dc-dc converters are used to interface storage element and loads. Use of master-slave controller for paralleling is restricted on account of its high cost, low reliability and complexity. Even though conventional droop controllers overwhelmed these limitations, they cannot concurrently ensure equal current sharing and low-voltage regulation. This is attributable to the error in measurement of voltage feedback signal. To address this limitation, modified droop controller based on model predictive control is proposed in this study. This work presents a performance study of a dc micro grid when it is used a voltage droop technique to regulated the bus voltage and to control the load sharing between different sources. The structure of the simple dc micro grid studied consists of renewable ene...

The Journal of Engineering, 2009

We present a two-stage inverter with high-voltage conversion ratio employing modified finite-set ... more We present a two-stage inverter with high-voltage conversion ratio employing modified finite-set model predictive control (MPC) for utility-integrated low-power photovoltaic (PV) applications. The proposed system is suitable for low PV power applications, the calculated efficiency at 150 W input power and 21 times boosting ratio was around 88%. The presented system is a high gain, transformerless, and with less leakage current system. Switched inductor quadratic boost converter composes the first stage of the proposed system, due to its high stepup ability. It can boost the input voltage up to 30 times. A five-switch current-source inverter represents the dc/ac stage. The MPC algorithm are designed to control the system and perform the following tasks, take out the maximum power (MP) from the PV, controls the proposed system to operate at maximum power, step-up the PV voltage, and introduces low current with low total harmonic distortion (THD) and with unity power factor with the grid voltage. Switching states are selected to reduce the switching losses, but forcing the h-bridge switches to operate at the fundamental frequency.

IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society, 2014

ABSTRACT this paper presents High-gain power conditioning system for grid connected PV applicatio... more ABSTRACT this paper presents High-gain power conditioning system for grid connected PV applications. The construction of the proposed system consists of high-gain Switched Inductor Quadratic Boost Inverter (SIQBI) and five-switch h-bridge inverter. The proposed system is controlled to satisfy the following criteria: extract maximum power from PV module, boost dc voltage to higher level and inject sinusoidal current in phase with the grid voltage. Proportional Resonant Controller (PRC) is used to control the inversion stage to inject sinusoidal current into the grid. Simulation results and detailed analysis are discussed in details through this paper. Experimental prototype is built, samples of the experimental results are figured out and discussed.

Energies, Dec 1, 2022

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

2022 IEEE 63th International Scientific Conference on Power and Electrical Engineering of Riga Technical University (RTUCON)

Energies

High penetration of renewable energy sources into isolated microgrids (µGs) is considered a criti... more High penetration of renewable energy sources into isolated microgrids (µGs) is considered a critical challenge, as µGs’ operation at low inertia results in frequency stability problems. To solve this challenge, virtual inertia control based on an energy storage system is applied to enhance the inertia and damping properties of the µG. On the other hand, utilization of a phase-locked loop (PLL) is indispensable for measuring system frequency; however, its dynamics, such as measurement delay and noise generation, cause extra deterioration of frequency stability. In this paper, to improve µG frequency stability and minimize the impact of PLL dynamics, a new optimal frequency control technique is proposed. A whale optimization algorithm is used to enhance the virtual inertia control loop by optimizing the parameters of the virtual inertia controller with consideration of PLL dynamics and the uncertainties of system inertia. The proposed controller has been validated through comparisons ...

IEEE Access, 2022

PV systems are penetrating the energy generation market rapidly. PV system output strongly depend... more PV systems are penetrating the energy generation market rapidly. PV system output strongly depends on environmental conditions. As a result, the utilization of power electronic converters is mandatory. On the other hand, most modern loads, from small to big ones, are based on dc, similar to the renewable sources generating dc. Hence, wide adoption of residential dc microgrids (RDCμGs) based on PV energy would be a trend soon, following modern developments in energy-efficient buildings. This paper targets power converters for the integration of PV systems into RDCμGs. It considers two main classes: high stepup converters for PV module-level, parallel optimizer, applications, and non-isolated buck-boost converters for the PV string, series optimizer, applications. Due to the importance of the PV topic, a significant number of topologies have been introduced in the literature. However, not all topologies attracted the interest of the industry. This review paper considers PV converters used in industry or demonstrated in academia at a high technology readiness level with comprehensive experimental justification. This allows us to focus this review on the most valuable solutions and to provide a guide for both industry and academic readers. In the end, future trends in industrial PV systems and power converters are discussed.

IEEE Access

The converter efficiency defines the overall efficiency of a renewable energy system. In a full p... more The converter efficiency defines the overall efficiency of a renewable energy system. In a full power converter, its components process the whole input power, even if it is not mandatory. Partial power processing (PPP) is an exciting concept for improving overall system efficiency and reducing system cost and size. In PPP, the converter processes the amount of power needed to be processed. This work proposes a PPP based on the high-performance Quasi-Z-Source Series Resonance converter (QZSSRC). The proposed partial power converter has a series-input parallel-output (SIPO) architecture. Previous publications in this area mainly consider converters with step-down voltage regulation, like the phase-shifted full-bridge converter. They underperform in this application due to operating at the maximum power when bucking the voltage the most. This paper studies two other types of dc-dc converters, buck-boost and boost, in SIPO partial power converters. Theoretical operation principles are corroborated with full experimental results given and analyzed. A 300 W prototype of the QZSSRC is used to convert the power of up to 2 kW in a PPP system with overall system efficiency over 99%. INDEX TERMS Power converters, partial power processing (PPP), quasi Z-source series resonance converter (QZSSRC), step up, step down, efficiency.

2019 International Conference on Innovative Trends in Computer Engineering (ITCE)

current source inverter (CSI) requires particular modulation strategy due to its configuration an... more current source inverter (CSI) requires particular modulation strategy due to its configuration and principle of operation. An overlap period of time between the switching states is necessary so as not to cut the input inductor current. When operated by space vector pulse width modulation (SVPWM), this overlap instant results in current harmonic distortions. The current distortions deteriorates the quality of electric power delivered by CSI. The following paper introduces a comparative study between five and seven segment modulation sequences of SVPWM, and investigates their effect on the current distortions resulted by the overlap instant. The study finally recommends one modulation sequence over the other to alleviate the impact of the overlap instant on the output current waveform.

2022 IEEE 13th International Symposium on Power Electronics for Distributed Generation Systems (PEDG)

2022 IEEE 7th International Energy Conference (ENERGYCON)

2019 IEEE Conference on Power Electronics and Renewable Energy (CPERE)

Micro-inverters recently become more attractive due to its modularity and independent maximum pow... more Micro-inverters recently become more attractive due to its modularity and independent maximum power point tracking for each individual photovoltaic (PV) module. Micro-Inverters designed for PV applications requires to perform different tasks such as extracting maximum power from PV, boost low PV voltage to a higher level and convert DC-voltage into AC voltage. Typically, a Micro-Inverter consists of two stages; a DC-DC Converter and DC-AC Inverter. This paper proposed a novel two-stage micro-inverter based on LLC resonant converter for grid integrated PV system. LLC resonant converter is presented as a first stage for the PV micro-inverter. and the second stage implemented from the three-phase inverter. The selection of the LLC resonant converter comes from its inherent features such as high efficiency converter for a wide range of input voltage and load variation, due to its capability to work under soft switching techniques like Zero Voltage Switching (ZVS) and Zero Current Switching (ZCS), possibility of achieving high voltage gain due to the presence of the HF transformer achieved. A complete feedback system is implemented in order to control maximum power of PV panel, maintain a fixed DC link voltage, and inject a sinusoidal current injected into the grid. The results have been validated by simulation and experimental topology vai OPAL-RT OP4510

Energies

In this article, a new non-inverting buck-boost converter with superior characteristics in both b... more In this article, a new non-inverting buck-boost converter with superior characteristics in both bucking and boosting is presented. The proposed converter has some distinct features, such as high step-up/-down ability and low voltage/current stress on its switching devices. The voltage gain of the proposed converter is double the reported value for the traditional buck-boost converter. Although it has three switches, the three switches operate simultaneously, hence no dead-time is required. Two out of the three switches are under voltage stress equal to half of the output voltage. The overall efficiency of the system is promising because of the ability to select devices with low voltage drops. Converter analysis and steady-state performance in both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) are presented in detail. A 1 kW hardware prototype of the converter was implemented in the laboratory; with a step-up ratio of 3.5 and 1 kW power, the measured effici...

Frontiers in Energy Research

Due to the low voltage of the PV module and to enable AC module technology, where every PV module... more Due to the low voltage of the PV module and to enable AC module technology, where every PV module has its own DC-AC converter, this paper introduces a new high step-up seven-level two-stage multilevel inverter for a grid-connected Photovoltaic (PV) system. The introduced schematic consists of two stages. The first stage is a switched capacitor boost converter and the second stage is a seven-level seven-switches multilevel inverter. The first stage is designed to extract the maximum power of PV module and step-up its input voltage. The proposed seven-level seven-switches topology generates seven levels with only seven switches. Thus, the number of switches is reduced. The proposed inverter has eight valid switching states. In each switching state only three switches are ON at the same time. The proposed topology has some distinct features such as reduced number of switches and reduced conduction; total harmonic distortion (THD) of the current is 23% in case of pure resistive and with...

2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe), 2016

This paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) app... more This paper presents two-stage power conditioning system for grid integrated Photovoltaic (PV) applications. The proposed system has distinct feature such as: high voltage gain, high efficiency, low voltage stress and galvanic isolation. The system is controlled via Model Predictive Control (MPC) to do the following functions: extract maximum power from the PV generator, and inject a sinusoidal current into the utility with unity power factor.

Journal of Electrical Engineering & Technology, 2017

– We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set... more – We present a two-stage inverter with high step-up conversion ratio engaging modified finite-set Model Predictive Control (MPC) for utility-integrated photovoltaic (PV) applications. The anticipated arrangement is fit for low power PV uses, the calculated efficiency at 150 W input power and 19 times boosting ratio was around 94%. The suggested high-gain dc-dc converter based on Cockcroft-Walton multiplier constitutes the first-stage of the offered structure, due to its high step-up ability. It can boost the input voltage up to 20 times. The 3S current-source inverter constitutes the second-stage. The 3S current-source inverter hires three semiconductor switches, in which one is functioning at high-frequency and the others are operating at fundamental-frequency. The high-switching pulses are varied in the procedure of unidirectional sine-wave to engender a current coordinated with the utility-voltage. The unidirectional current is shaped into alternating current by the synchronized push-pull configuration. The MPC process are intended to control the scheme and achieve the subsequent tasks, take out the Maximum Power (MP) from the PV, step-up the PV voltage, and introduces low current with low Total Harmonic Distortion (THD) and with unity power factor with the grid voltage.

Electronics, 2022

This article proposes a new high-gain transformerless dc/dc boost converter. Although they posses... more This article proposes a new high-gain transformerless dc/dc boost converter. Although they possess the ability to boost voltage at higher voltage levels, converter switching devices are under low voltage stress. The voltage stress on active switching devices is lower than the output voltage. Therefore, low-rated components are used to implement the converter. The proposed converter can be considered as a promising candidate for PV microconverter applications, where high voltage-gain is required. The principle of operation and the steady-state analysis of the converter in the continuous conduction mode are presented. A hardware prototype for the converter is implemented in the laboratory to prove the concept of operation.

2019 21st International Middle East Power Systems Conference (MEPCON), 2019

Direct Matrix Converter (DMC) is superior topology for AC/AC power transformation. Its superiorit... more Direct Matrix Converter (DMC) is superior topology for AC/AC power transformation. Its superiority comes from its inherent advantages such as: small size, no electrolytic capacitors, and straight conversion ability. Multiphase machines, would be the future trend in high power applications due to their features; better torque concentration, less torque pulsations, and superior fault tolerance. This paper introduces the usage of five-phase Induction Motor (IM). For that purpose, a three-to-five DMC is required to drive the five-phase induction motor without affecting the existing three-phase system. An improved Model-Predictive Torque Control (MPTC) is presented in this paper to regulate the toque and the speed of the five-phase induction motor. a 15 kW five-phase IM is simulated using MATLAB platform. The functionality of the closed loop system confirms the strength and robustness of the anticipated technique.

SVU-International Journal of Engineering Sciences and Applications, 2021

In this article, a new high gain dc/dc converter is proposed that can be used with applications t... more In this article, a new high gain dc/dc converter is proposed that can be used with applications that require elevating output voltage to higher voltage-level such as PV applications. The proposed configuration is able to achieve high-voltage-gain, compared to any other transformerless topologies. The voltage stresses on the active MOSFETs are lower than half of the output voltage. Hence, low rated components are selected. The principles of operation of the two configurations are analyzed in details. Hardware prototype is implemented in the lab, in order to verify the analytical analysis of the topology.

2019 IEEE Applied Power Electronics Conference and Exposition (APEC), 2019

Usually, power converters are used to deliver renewable energy to the grid. The operation of thes... more Usually, power converters are used to deliver renewable energy to the grid. The operation of these converters greatly impacts the power quality and reliability of the power system. Hence, more attention should be paid to the performance of such power electronic systems. Being one of these converters, current source inverter (CSI) operation is influenced by the overlap period (OLP) that is included in its pulse-train to prevent voltage spikes. The OLP results in waveform distortions and vector deviation error. This study proposes an overlap technique and optimizes the modulation sequence that reduced the effect of OLP remarkably. The ampere-second analysis of the dwell times of the modulation vectors is provided, the resulted error expressions are derived. Hardware prototype is being implemented in the lab and a sample of the results are provided.

2016 19th International Conference on Electrical Machines and Systems (ICEMS), 2016

Dc structures are acquisitioning acceptance owing to its high efficiency, high reliability and ea... more Dc structures are acquisitioning acceptance owing to its high efficiency, high reliability and easy interconnection of renewable sources as compared to ac systems. In standalone dc system, parallel dc-dc converters are used to interface storage element and loads. Use of master-slave controller for paralleling is restricted on account of its high cost, low reliability and complexity. Even though conventional droop controllers overwhelmed these limitations, they cannot concurrently ensure equal current sharing and low-voltage regulation. This is attributable to the error in measurement of voltage feedback signal. To address this limitation, modified droop controller based on model predictive control is proposed in this study. This work presents a performance study of a dc micro grid when it is used a voltage droop technique to regulated the bus voltage and to control the load sharing between different sources. The structure of the simple dc micro grid studied consists of renewable ene...

The Journal of Engineering, 2009

We present a two-stage inverter with high-voltage conversion ratio employing modified finite-set ... more We present a two-stage inverter with high-voltage conversion ratio employing modified finite-set model predictive control (MPC) for utility-integrated low-power photovoltaic (PV) applications. The proposed system is suitable for low PV power applications, the calculated efficiency at 150 W input power and 21 times boosting ratio was around 88%. The presented system is a high gain, transformerless, and with less leakage current system. Switched inductor quadratic boost converter composes the first stage of the proposed system, due to its high stepup ability. It can boost the input voltage up to 30 times. A five-switch current-source inverter represents the dc/ac stage. The MPC algorithm are designed to control the system and perform the following tasks, take out the maximum power (MP) from the PV, controls the proposed system to operate at maximum power, step-up the PV voltage, and introduces low current with low total harmonic distortion (THD) and with unity power factor with the grid voltage. Switching states are selected to reduce the switching losses, but forcing the h-bridge switches to operate at the fundamental frequency.

IECON 2014 - 40th Annual Conference of the IEEE Industrial Electronics Society, 2014

ABSTRACT this paper presents High-gain power conditioning system for grid connected PV applicatio... more ABSTRACT this paper presents High-gain power conditioning system for grid connected PV applications. The construction of the proposed system consists of high-gain Switched Inductor Quadratic Boost Inverter (SIQBI) and five-switch h-bridge inverter. The proposed system is controlled to satisfy the following criteria: extract maximum power from PV module, boost dc voltage to higher level and inject sinusoidal current in phase with the grid voltage. Proportional Resonant Controller (PRC) is used to control the inversion stage to inject sinusoidal current into the grid. Simulation results and detailed analysis are discussed in details through this paper. Experimental prototype is built, samples of the experimental results are figured out and discussed.