A Double-Hybrid Spread-Spectrum Technique for EMI Mitigation in DC-DC Switching Regulators

Dousoky, Gamal M.,Shoyama, Masahito,Ninomiya, Tamotsu The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.4

Randomizing the switching frequency (RSF) to reduce the electromagnetic interference (EMI) of switching power converters is a well-known technique that has been previously discussed. The randomized pulse position (RPP) technique, in which the switching frequency is kept fixed while the pulse position (the delay from the starting of the switching cycle to the turn-on instant within the cycle) is randomized, has been previously addressed in the literature for the same purpose. This paper presents a double-hybrid technique (DHB) for EMI reduction in dc-dc switching regulators. The proposed technique employed both the RSF and the RPP techniques. To effectively spread the conducted-noise frequency spectrum and at the same time attain a satisfactory output voltage quality, two parameters (switching frequency and pulse position) were randomized, and a third parameter (the duty ratio) was controlled by a digital compensator. Implementation was achieved using field programmable gate array (FPGA) technology, which is increasingly being adopted in industrial electronic applications. To evaluate the contribution of the proposed DHB technique, investigations were carried out for each basic PWM, RPP, RSF, and DHB technique. Then a comparison was made of the performances achieved. The experimentally investigated features include the effect of each technique on the common-mode, differential-mode, and total conducted-noise characteristics, and their influence on the converter’s output ripple voltage.

Conducted-Noise Characteristics of a Digitally-Controlled Randomly-Switched DC-DC Converter with an FPGA-Based Implementation

Dousoky, Gamal M.,Shoyama, Masahito,Ninomiya, Tamotsu The Korean Institute of Power Electronics 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.3

This paper investigates the conducted-noise characteristics of a digitally-controlled randomly-switched dc-dc converter. In order to investigate the effect of the suggested digital controller on the conducted-noise characteristics of a dc-dc converter, three factors have been studied: the field-programmable gate array (FPGA) clock speed, the randomization ratio percentage, and the effect of using a closed loop feedback controller. A field-programmable gate array is much more flexible than analog control circuits, has a lower cost, and can be used for power supply applications. A novel FPGA-based implementation has been suggested for obtaining the experimental validations and realizing the studied concepts. Furthermore, the experimental results have been discussed and design guidelines have been included.

Improved Orientation Strategy for Energy-Efficiency in Photovoltaic Panels

Dousoky, Gamal M.,El-Sayed, Abou-Hashema M.,Shoyama, Masahito The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.3

This paper presents an improved orientation strategy for energy-efficiency in photovoltaic (PV) panels. Conventionally, PV panels are tilted with the site's latitude angle or the difference between the latitude angle and the solar declination angle. A monthly-based orientation strategy has been proposed and analyzed in this study. The proposed strategy implies that the PV panels are tilted with the monthly-based angle that achieves the maximum incident radiation. Furthermore, the impact of using the proposed orientation strategy and three conventional strategies on the produced power and on the PV system design features has been investigated in detail. A Japanese city (Fukuoka) and an Egyptian city (Al-Kharijah) have been considered as locations for the PV power system installation. The results showed that the proposed strategy achieved an increase in the power produced from the PV power systems at the two different sites, and consequently the required solar cells area can be saved. Therefore, the cost of the PV power system components can be reduced including the solar cells area and the land area.

Improved Orientation Strategy for Energy-Efficiency in Photovoltaic Panels

Gamal M. Dousoky,Abou-Hashema M. El-Sayed,Masahito Shoyama 전력전자학회 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.3

This paper presents an improved orientation strategy for energy-efficiency in photovoltaic (PV) panels. Conventionally, PV panels are tilted with the site’s latitude angle or the difference between the latitude angle and the solar declination angle. A monthly-based orientation strategy has been proposed and analyzed in this study. The proposed strategy implies that the PV panels are tilted with the monthly-based angle that achieves the maximum incident radiation. Furthermore, the impact of using the proposed orientation strategy and three conventional strategies on the produced power and on the PV system design features has been investigated in detail. A Japanese city (Fukuoka) and an Egyptian city (Al-Kharijah) have been considered as locations for the PV power system installation. The results showed that the proposed strategy achieved an increase in the power produced from the PV power systems at the two different sites, and consequently the required solar cells area can be saved. Therefore, the cost of the PV power system components can be reduced including the solar cells area and the land area.

Conducted-Noise Characteristics of a Digitally-Controlled Randomly-Switched DC-DC Converter with an FPGA-Based Implementation

Gamal M. Dousoky,Masahito Shoyama,Tamotsu Ninomiya 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.3

This paper investigates the conducted-noise characteristics of a digitally-controlled randomly-switched dc-dc converter. In order to investigate the effect of the suggested digital controller on the conducted-noise characteristics of a dc-dc converter, three factors have been studied: the field-programmable gate array (FPGA) clock speed, the randomization ratio percentage, and the effect of using a closed loop feedback controller. A field-programmable gate array is much more flexible than analog control circuits, has a lower cost, and can be used for power supply applications. A novel FPGA-based implementation has been suggested for obtaining the experimental validations and realizing the studied concepts. Furthermore, the experimental results have been discussed and design guidelines have been included.

Maximizing Energy-Efficiency in Single-Axis Solar Trackers for Photovoltaic Panels

Gamal M. DOUSOKY,Abou-Hashema M. EL-SAYED,Masahito SHOYAMA 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper presents an improved orientation strategy for energy-efficiency in PV panels: The PV panels are tilted with a monthly-based angle that achieves maximum incident radiation. Furthermore, the impact of using the proposed strategy and other three conventional strategies on the PV system features has been investigated. A Japanese city (Fukuoka) and an Egyptian city (Al-Kharijah) have been considered for this study. The results showed that the proposed strategy achieved an increase in the produced energy from the PV. Therefore, the cost of the PV power system components can be reduced including the solar cells area, and the land area.

A Double-Hybrid Spread-Spectrum Technique for EMI Mitigation in DC-DC Switching Regulators

Gamal M. Dousoky,Masahito Shoyama,Tamotsu Ninomiya 전력전자학회 2010 JOURNAL OF POWER ELECTRONICS Vol.10 No.4

Randomizing the switching frequency (RSF) to reduce the electromagnetic interference (EMI) of switching power converters is a well-known technique that has been previously discussed. The randomized pulse position (RPP) technique, in which the switching frequency is kept fixed while the pulse position (the delay from the starting of the switching cycle to the turn-on instant within the cycle) is randomized, has been previously addressed in the literature for the same purpose. This paper presents a double-hybrid technique (DHB) for EMI reduction in dc-dc switching regulators. The proposed technique employed both the RSF and the RPP techniques. To effectively spread the conducted-noise frequency spectrum and at the same time attain a satisfactory output voltage quality, two parameters (switching frequency and pulse position) were randomized, and a third parameter (the duty ratio) was controlled by a digital compensator. Implementation was achieved using field programmable gate array (FPGA) technology, which is increasingly being adopted in industrial electronic applications. To evaluate the contribution of the proposed DHB technique, investigations were carried out for each basic PWM, RPP, RSF, and DHB technique. Then a comparison was made of the performances achieved. The experimentally investigated features include the effect of each technique on the common-mode, differential-mode, and total conducted-noise characteristics, and their influence on the converter’s output ripple voltage.

New Design Approach for Grid-Current-Based Active Damping of LCL Filter Resonance in Grid-Connected Converters

Gaafar, Mahmoud A.,Dousoky, Gamal M.,Ahmed, Emad M.,Shoyama, Masahito,Orabi, Mohamed The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

This paper investigates the active damping of grid-connected LCL filter resonance using high-pass filter (HPF) of the grid current. An expression for such HPF is derived in terms of the filter components. This expression facilitates a general study of the actively damped filter behavior in the discrete time domain. Limits for the HPF parameters are derived to avoid the excitation of unstable open loop poles since such excitation can reduce both the damping performance and the system robustness. Based on this study, straightforward co-design steps for the active damping loop along with the fundamental current regulator are proposed. A numerical example along with simulation and experimental results are presented to verify the theoretical analyses.

New Design Approach for Grid-Current-Based Active Damping of LCL Filter Resonance in Grid-Connected Converters

Mahmoud A. Gaafar,Gamal M. Dousoky,Emad M. Ahmed,Masahito Shoyama,Mohamed Orabi 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.4

This paper investigates the active damping of grid-connected LCL filter resonance using high-pass filter (HPF) of the grid current. An expression for such HPF is derived in terms of the filter components. This expression facilitates a general study of the actively damped filter behavior in the discrete time domain. Limits for the HPF parameters are derived to avoid the excitation of unstable open loop poles since such excitation can reduce both the damping performance and the system robustness. Based on this study, straightforward co-design steps for the active damping loop along with the fundamental current regulator are proposed. A numerical example along with simulation and experimental results are presented to verify the theoretical analyses.