EPE Association: EPE 2013 - LS4b: Photovoltaic Converters and their Control

EPE 2013 - LS4b: Photovoltaic Converters and their Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 15: Non-rotating power generation and storage systems > EPE 2013 - LS4b: Photovoltaic Converters and their Control

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   1-MW Advanced T-type NPC Converters for Solar Power Generation System
By Kansuke FUJII, Takayuki KIKUCHI, Hisashi KOUBAYASHI, Kazuyuki YODA [View]
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Abstract: A multi-level topology is one of the effective approaches to improve the efficiency of power converters. Recently, three-level converters are used not only in medium voltage converters but also in low voltage converters in order to improve the conversion efficiency. Advanced T-type NPC (AT-NPC) converter belongs to three-level converters and utilizes Reverse-Blocking IGBT (RB-IGBT) as a bi-directional switch. The AT-NPC topology is simple and enables low conduction losses of the converters. This time, the authors develop a 1-MW photovoltaic converter using AT-NPC topology. This photovoltaic converter is outdoor-type transformer-less single-stage converter, and consists of four 250-kW power units. In addition, to reduce EMI from the converter, the neutral point of the LC filter is connected to the medium point of the DC-link voltage. This paper describes the features of this solar power inverter, power units using AT-NPC IGBT modules connected in parallel and the evaluation results.

   A Cell-Level Photovoltaic Model for High-Granularity Simulations
By Carlos OLALLA, Daniel CLEMENT, Dragan MAKSIMOVIC, Chris DELINE [View]
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Abstract: This paper presents a cell-level simulation model of photovoltaic (PV) systems that is capable of reproducing partial-shading and other mismatch effects at high granularity. The nonlinear diode voltage-current characteristic is stored in a piecewise-linear model, and the stored values are employed to compute the Jacobian matrices very efficiently. As a result, the model can be solved with low computational effort, so that simulations at cell-level granularity and over long time spans can be carried out efficiently. The model is well suited for evaluations of energy capture, including the effects of partial shading or other mismatches, in large PV systems over long periods of time. Comparisons of simulation and experimental results are provided for three representative PV systems.

   A Novel Low Cost Solar Central Inverters Topology With 99.2 \% Efficiency
By Heiko PRECKWINKEL, Krishna DORA, Norbert FRÖHLEKE, Joachim BOCKER, Andreas BUNTE [View]
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Abstract: For solar central inverters, high efficiency is still a very important issue. It increases the yield, but even more important, it reduces the thermal stress of all components, minimizes the cooling effort or allows higher ambient temperatures. The main challenge is not only to reach high peak efficiency in one operation point but more to provide a good performance over the whole voltage and power range.In this contribution, a new topology for central inverters connected to the medium-voltage grid is presented, analyzed and practically examined. Measurements on a 100 kW prototype prove this concept by an excellent high and flat efficiency graph peaking at 99.2 \%. This result is obtained with conventional silicon semiconductors.

EPE 2013 - LS4b: Photovoltaic Converters and their Control
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2013 ECCE Europe - Conference > EPE 2013 - Topic 15: Non-rotating power generation and storage systems > EPE 2013 - LS4b: Photovoltaic Converters and their Control
	[return to parent folder]

	1-MW Advanced T-type NPC Converters for Solar Power Generation System By Kansuke FUJII, Takayuki KIKUCHI, Hisashi KOUBAYASHI, Kazuyuki YODA	[View] [Download]
Abstract: A multi-level topology is one of the effective approaches to improve the efficiency of power converters. Recently, three-level converters are used not only in medium voltage converters but also in low voltage converters in order to improve the conversion efficiency. Advanced T-type NPC (AT-NPC) converter belongs to three-level converters and utilizes Reverse-Blocking IGBT (RB-IGBT) as a bi-directional switch. The AT-NPC topology is simple and enables low conduction losses of the converters. This time, the authors develop a 1-MW photovoltaic converter using AT-NPC topology. This photovoltaic converter is outdoor-type transformer-less single-stage converter, and consists of four 250-kW power units. In addition, to reduce EMI from the converter, the neutral point of the LC filter is connected to the medium point of the DC-link voltage. This paper describes the features of this solar power inverter, power units using AT-NPC IGBT modules connected in parallel and the evaluation results.

	A Cell-Level Photovoltaic Model for High-Granularity Simulations By Carlos OLALLA, Daniel CLEMENT, Dragan MAKSIMOVIC, Chris DELINE	[View] [Download]
Abstract: This paper presents a cell-level simulation model of photovoltaic (PV) systems that is capable of reproducing partial-shading and other mismatch effects at high granularity. The nonlinear diode voltage-current characteristic is stored in a piecewise-linear model, and the stored values are employed to compute the Jacobian matrices very efficiently. As a result, the model can be solved with low computational effort, so that simulations at cell-level granularity and over long time spans can be carried out efficiently. The model is well suited for evaluations of energy capture, including the effects of partial shading or other mismatches, in large PV systems over long periods of time. Comparisons of simulation and experimental results are provided for three representative PV systems.

	A Novel Low Cost Solar Central Inverters Topology With 99.2 \% Efficiency By Heiko PRECKWINKEL, Krishna DORA, Norbert FRÖHLEKE, Joachim BOCKER, Andreas BUNTE	[View] [Download]
Abstract: For solar central inverters, high efficiency is still a very important issue. It increases the yield, but even more important, it reduces the thermal stress of all components, minimizes the cooling effort or allows higher ambient temperatures. The main challenge is not only to reach high peak efficiency in one operation point but more to provide a good performance over the whole voltage and power range.In this contribution, a new topology for central inverters connected to the medium-voltage grid is presented, analyzed and practically examined. Measurements on a 100 kW prototype prove this concept by an excellent high and flat efficiency graph peaking at 99.2 \%. This result is obtained with conventional silicon semiconductors.