EPE Association: EPE 2019 - LS3e: Photovoltaics

EPE 2019 - LS3e: Photovoltaics
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 05: Renewable Energy Power Systems > EPE 2019 - LS3e: Photovoltaics

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   A Single-Phase dc-ac Dual-Active-Bridge Based Resonant Converter For Grid-Connected Photovoltaic (PV) Applications
By Marcos AGUIRRE [View]
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Abstract: This paper presents the topology, modelling and control strategy for a single-phase grid-connected converter for photovoltaic (PV) applications based on the series-resonant dual active bridge (DAB). A state-space large-signal model is derived for phase-shift based modulations, and a linearized model is presented for control design. A multi-loop control strategy is presented where a current-control loop regulates the current that the converter injects in-phase with the grid voltage, while a slower loop regulates the PV array voltage for MPPT. To verify the model and control strategy, simulation and experimental results are presented.

   An Intelligent Pass-Through Algorithm for Non-Inverting Buck-Boost Solar Power Optimizers
By Leonardo CALLEGARO [View]
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Abstract: The non-inverting buck-boost is a converter topology commonly encountered in renewable energy applications, as it is able to provide a wide range of output voltages, while its input voltage can be regulated to extract the maximum power available from the source. When input and output voltage of this converter are in close proximity, special dead-zone avoidance controls must be activated, in order to achieve stable operation. Abundant literature documents detrimental effects of the dead-zone, deemed to cause uncontrollability, increased ripple and sub-harmonic oscillations in the regulated voltage.This paper proposes a new algorithm to avoid the operational dead-zone in the non-inverting buck-boost converter by introducing a pass-through operation. In this mode, the input port is directly linked to the output port of the converter, avoiding pulse width modulation (PWM) switching, whenever the voltage at these two ports is within a narrow range. Existing dead-zone avoidance techniques rely on using extra switches, or on using a buck-boost operation which inevitably increases the conversion losses. Conversely, the proposed technique does not rely on simultaneous buck and boost PWM operation and does not need additional hardware to activate the pass-through mode. The presented control algorithm is thoroughly discussed and implemented in a digital microcontroller. Finally, efficiency measurements and experimental results executed on a 200 W non-inverting buck-boost photovoltaic module integrated converter are used for performance evaluation.

   Evaluation of Grid-Connected PV Converter Power Module Technologies in Terms of Efficiency, Initial Cost, and Return on Investment Time
By Oguzhan OZTOPRAK [View]
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Abstract: The voltage source converter (VSC) of the grid connected photovoltaic (PV) systems is the most technological component in a PV system and contributes to 5-15\% of the whole investment. As the cost and energy efficiency of a VSC are two factors that determine the total system economics, the system total cost of ownership (TCO) should be optimized during the VSC design. This paper provides a design methodology for grid connected VSCs considering TCO, the return on investment (ROI) and payback period (PP) as the basic criterion for optimization. In the design, since power electronics is entering the wide-bandgap device technology age, higher efficiency and faster wide bandgap devices are also weighed along with the silicon IGBT (Si-IGBT) technology. In the paper, the power module, passives (LCL filter) and heatsink are designed and compared with the conventional design as reference. The comparative and progressive design study of a 1-MW PV power plant with 30-kW string PV converters demonstrates the advantages of design with wide bandgap devices. The investigation is conveyed via theory, analytical methods, and experiments.

   Performance Evaluation of a Boost Integrated Three-Phase PV Inverter Operating With Current Unfolding Principle
By Tomoyuki MANNEN [View]
[Download]

Abstract: This paper proposes a high-efficiency boost integrated three-phase PV inverter. The proposed invertercan reduce total number of switching and increase its efficiency. The 1.2-kW experimental verificationsconfirm the validity of the proposed inverter and exhibit a great loss reduction of approximately 60\%compared to the conventional boost-converter and three-phase-inverter approach.

EPE 2019 - LS3e: Photovoltaics
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2019 ECCE Europe - Conference > EPE 2019 - Topic 05: Renewable Energy Power Systems > EPE 2019 - LS3e: Photovoltaics
	[return to parent folder]

	A Single-Phase dc-ac Dual-Active-Bridge Based Resonant Converter For Grid-Connected Photovoltaic (PV) Applications By Marcos AGUIRRE	[View] [Download]
Abstract: This paper presents the topology, modelling and control strategy for a single-phase grid-connected converter for photovoltaic (PV) applications based on the series-resonant dual active bridge (DAB). A state-space large-signal model is derived for phase-shift based modulations, and a linearized model is presented for control design. A multi-loop control strategy is presented where a current-control loop regulates the current that the converter injects in-phase with the grid voltage, while a slower loop regulates the PV array voltage for MPPT. To verify the model and control strategy, simulation and experimental results are presented.

	An Intelligent Pass-Through Algorithm for Non-Inverting Buck-Boost Solar Power Optimizers By Leonardo CALLEGARO	[View] [Download]
Abstract: The non-inverting buck-boost is a converter topology commonly encountered in renewable energy applications, as it is able to provide a wide range of output voltages, while its input voltage can be regulated to extract the maximum power available from the source. When input and output voltage of this converter are in close proximity, special dead-zone avoidance controls must be activated, in order to achieve stable operation. Abundant literature documents detrimental effects of the dead-zone, deemed to cause uncontrollability, increased ripple and sub-harmonic oscillations in the regulated voltage.This paper proposes a new algorithm to avoid the operational dead-zone in the non-inverting buck-boost converter by introducing a pass-through operation. In this mode, the input port is directly linked to the output port of the converter, avoiding pulse width modulation (PWM) switching, whenever the voltage at these two ports is within a narrow range. Existing dead-zone avoidance techniques rely on using extra switches, or on using a buck-boost operation which inevitably increases the conversion losses. Conversely, the proposed technique does not rely on simultaneous buck and boost PWM operation and does not need additional hardware to activate the pass-through mode. The presented control algorithm is thoroughly discussed and implemented in a digital microcontroller. Finally, efficiency measurements and experimental results executed on a 200 W non-inverting buck-boost photovoltaic module integrated converter are used for performance evaluation.

	Evaluation of Grid-Connected PV Converter Power Module Technologies in Terms of Efficiency, Initial Cost, and Return on Investment Time By Oguzhan OZTOPRAK	[View] [Download]
Abstract: The voltage source converter (VSC) of the grid connected photovoltaic (PV) systems is the most technological component in a PV system and contributes to 5-15\% of the whole investment. As the cost and energy efficiency of a VSC are two factors that determine the total system economics, the system total cost of ownership (TCO) should be optimized during the VSC design. This paper provides a design methodology for grid connected VSCs considering TCO, the return on investment (ROI) and payback period (PP) as the basic criterion for optimization. In the design, since power electronics is entering the wide-bandgap device technology age, higher efficiency and faster wide bandgap devices are also weighed along with the silicon IGBT (Si-IGBT) technology. In the paper, the power module, passives (LCL filter) and heatsink are designed and compared with the conventional design as reference. The comparative and progressive design study of a 1-MW PV power plant with 30-kW string PV converters demonstrates the advantages of design with wide bandgap devices. The investigation is conveyed via theory, analytical methods, and experiments.

	Performance Evaluation of a Boost Integrated Three-Phase PV Inverter Operating With Current Unfolding Principle By Tomoyuki MANNEN	[View] [Download]
Abstract: This paper proposes a high-efficiency boost integrated three-phase PV inverter. The proposed invertercan reduce total number of switching and increase its efficiency. The 1.2-kW experimental verificationsconfirm the validity of the proposed inverter and exhibit a great loss reduction of approximately 60\%compared to the conventional boost-converter and three-phase-inverter approach.