EPE Association: EPE 2017 - DS2h: Solar Energy Systems II

EPE 2017 - DS2h: Solar Energy Systems II
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 05: Renewable Energy Power Systems > EPE 2017 - DS2h: Solar Energy Systems II

   [return to parent folder]

   A Distributed Maximum Power Point Tracking System for Solar Electric Vehicles
By Arjo VAN DER HAM [View]
[Download]

Abstract: Current Solar Electric Vehicles have flat roofs, in an attempt to reduce irradiance mismatches within the strings of PV cells. As a result the aerodynamic performance and design freedom of such vehicles are limited. This paper presents a distributed maximum power point tracking methodology specifically aimed at Solar Electric Vehicles to overcome this problem. As a starting point, the PV-to-isolated bus architecture is selected, since it processes a low amount of power and easily extends to an arbitrary number of groups per string. A new control strategy for this architecture is introduced, that allows for local, decoupled, true maximum power point tracking. The architecture requires isolated, bidirectional, load independent converters, which were realized by means of a series connected synchronous boost converter and LLC resonant converter.

   AN ANALOG GLOBAL MAXIMUM POWER POINT TRACKING FOR PHOTOVOLTAIC SYSTEMS: APPLICATION TO NANOSPACECRAFTS
By Ausias GARRIGOS [View]
[Download]

Abstract: In this work, an Analog Global Maximum Power Point Tracker (A-GMPPT) is introduced and discussed. The underlying idea of this A-GMPPT is the peak power tracking using a capacitive load, in particular the filter input capacitance of the DC/DC converter. Therefore, this technique is well suited for photovoltaic-battery systems and it could be a replacement for traditional open circuit Maximum Power Point Trackers. An interesting field of application is on nanospacecraft power systems, especially in those that include complex photovoltaic arrangements prone to exhibit multiple local maximum power points. Description, simulation and experimental validation of the proposed method is detailed in this paper.

   Control Strategy for an Integrated Photovoltaic-Battery System
By Andoni URTASUN [View]
[Download]

Abstract: In photovoltaic-battery systems, more attention is usually paid to the MPPT control while the battery management is put aside. This paper proposes two control strategies for an integrated PV-battery system, both of them making it possible to perform MPPT or regulate the battery voltage to its maximum value in order to prevent it from overcharging. Simulation results prove the feasibility of both controls.

   New approach for localization global maximum of solar array
By Moshe AVERBUKH [View]
[Download]

Abstract: Today's PV solar power plants would be unimaginable without Maximum Power Point Tracking (MPPT) which automatically maximizes panels power output, thereby significantly increasing energy production. However, partial shading of PV panels in large solar plants is a serious obstacle for MPPT. Multiple local extremums will be observed while only one is the global maximum and has to be found. Some methods and algorithms for solving the problem of tracking the global maximum among locals are known. However, most require a prolonged search time with, therefore, diminished efficiency in situations characterized by sudden variation in solar irradiation. A uniquely efficient algorithm and electronic device was developed for improving total MPPT functionality. It is accomplished by tracking global maximum boundaries, the positions of which are translated into traditional MPPT with substantial localization accuracy. This localization algorithm is based on the assessment of each panel's current together with the usage of a simplified PV equivalent circuit.The proposed algorithm can determine the global maximum on an I-P curve at relatively high speeds, and is only restricted by digital control ability. Currently, this task would take no more than 50-100 us maximum. Therefore, the global maximum in any set of rapidly changing shading conditions can be found. Importantly, however, some unsolved questions remain regarding accuracy and sustainability of this approach. The present work analyzes these essential properties and concludes with the proposed MPPT algorithm.

   NPC Three Level Inverter With Dual DC Bus For Independent Distributed Generators. Neutral-Point Voltage Balancing Under The Input Power Imbalance.
By MILOSZ SZAREK [View]
[Download]

Abstract: This paper concerns the application of three-level neutral point clamped (NPC) voltage source inverter (VSI) to electrical energy conversion of the photovoltaic (PV) power plant. The grid-connected3-phase NPC inverter is powered via the split DC-link composed of the capacitive divider. It enables the usage of two DC-buses independently which can be supplied by the separated boost-typeDC-DC converters. They are used to generate the maximal power value (MPP) from each string of PV modules. The main objective of this paper is the analysis of a DC-link voltage unbalance effect anddevelopment of dedicated balancing control algorithm based on the 7-segment space vector modulation method (SVM). The goal of proposed solution is proper operation of the three-phase NPCinverter under permanent input PV power unbalance. In the presented paper the maximal permissible level of input power unbalance was estimated which can be compensated by the use ofdeveloped NPC inverter modulation method as a function of the instantaneous operation point (e.g. amplitude modulation index). The listed issues were verified via simulation research performed in Maltab\Simulink software as well as experimentally via the laboratory tests.

   Power Flow Interactive Sharing between Two DC Nanogrids Photovoltaic Local Branch Dynamic Systems at Island Operation
By Maged BAUOMY [View]
[Download]

Abstract: Nowadays DC nanogrid topologies are going spread with the deployment of distributed generation. Therefore, the investigation of interactive sharing between DC nanogrid branches is mandatory to realize a continuous operation of the photovoltaic considering: maximum power tracking, Off-maximum power point tracking, load sharing, and battery charge sharing. This paper discusses the power flow interaction among two DC nanogrids in island mode. To demonstrate that, a detailed dynamic branch modeling systems is proposed. The MPPT and Off-MPPT control are tested on this nanogrid dynamic model; the MPPT is working continuously unless the two BSS are fully charged which is known by the reference indicator state of charge (SOC) value. If the BSS reaches SOC 100 \%, the Off-MPPT control will be operated to stop extraction of more power. The objective of interactive sharing is proposed by a control approach for the bidirectional converter utilized in charging and discharging of BSS. This control approach with the support of simple nanogrid controller transfers power via transmission line to performs load sharing and BSS charging of the nanogrid. The power transfer between the two buses will be performed by rising the sending bus voltage above the receiving bus.

   Single-phase transformerless PV inverter topology with AC bypass and mid-DC-link voltage clamping
By GEORGIOS ORFANOUDAKIS [View]
[Download]

Abstract: Transformerless PV inverters are known to generate undesirable ground leakage currents due to the lack of galvanic isolation between the PV array and the electric grid. This paper initially discusses the different types of transformerless PV inverter topologies that have been proposed to overcome this problem. It then proposes a new topology, which extends the commercially successful HERIC inverter with the addition of a mid-DC-link clamping configuration. Such configurations are known to cause a highly desirable reduction of the ground leakage currents, which is demonstrated through simulation results from MATLAB-Simulink and PLECS. The proposed topology is finally compared to other transformerless topologies with respect to other aspects, such as efficiency and component count.

EPE 2017 - DS2h: Solar Energy Systems II
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 05: Renewable Energy Power Systems > EPE 2017 - DS2h: Solar Energy Systems II
	[return to parent folder]

	A Distributed Maximum Power Point Tracking System for Solar Electric Vehicles By Arjo VAN DER HAM	[View] [Download]
Abstract: Current Solar Electric Vehicles have flat roofs, in an attempt to reduce irradiance mismatches within the strings of PV cells. As a result the aerodynamic performance and design freedom of such vehicles are limited. This paper presents a distributed maximum power point tracking methodology specifically aimed at Solar Electric Vehicles to overcome this problem. As a starting point, the PV-to-isolated bus architecture is selected, since it processes a low amount of power and easily extends to an arbitrary number of groups per string. A new control strategy for this architecture is introduced, that allows for local, decoupled, true maximum power point tracking. The architecture requires isolated, bidirectional, load independent converters, which were realized by means of a series connected synchronous boost converter and LLC resonant converter.

	AN ANALOG GLOBAL MAXIMUM POWER POINT TRACKING FOR PHOTOVOLTAIC SYSTEMS: APPLICATION TO NANOSPACECRAFTS By Ausias GARRIGOS	[View] [Download]
Abstract: In this work, an Analog Global Maximum Power Point Tracker (A-GMPPT) is introduced and discussed. The underlying idea of this A-GMPPT is the peak power tracking using a capacitive load, in particular the filter input capacitance of the DC/DC converter. Therefore, this technique is well suited for photovoltaic-battery systems and it could be a replacement for traditional open circuit Maximum Power Point Trackers. An interesting field of application is on nanospacecraft power systems, especially in those that include complex photovoltaic arrangements prone to exhibit multiple local maximum power points. Description, simulation and experimental validation of the proposed method is detailed in this paper.

	Control Strategy for an Integrated Photovoltaic-Battery System By Andoni URTASUN	[View] [Download]
Abstract: In photovoltaic-battery systems, more attention is usually paid to the MPPT control while the battery management is put aside. This paper proposes two control strategies for an integrated PV-battery system, both of them making it possible to perform MPPT or regulate the battery voltage to its maximum value in order to prevent it from overcharging. Simulation results prove the feasibility of both controls.

	New approach for localization global maximum of solar array By Moshe AVERBUKH	[View] [Download]
Abstract: Today's PV solar power plants would be unimaginable without Maximum Power Point Tracking (MPPT) which automatically maximizes panels power output, thereby significantly increasing energy production. However, partial shading of PV panels in large solar plants is a serious obstacle for MPPT. Multiple local extremums will be observed while only one is the global maximum and has to be found. Some methods and algorithms for solving the problem of tracking the global maximum among locals are known. However, most require a prolonged search time with, therefore, diminished efficiency in situations characterized by sudden variation in solar irradiation. A uniquely efficient algorithm and electronic device was developed for improving total MPPT functionality. It is accomplished by tracking global maximum boundaries, the positions of which are translated into traditional MPPT with substantial localization accuracy. This localization algorithm is based on the assessment of each panel's current together with the usage of a simplified PV equivalent circuit.The proposed algorithm can determine the global maximum on an I-P curve at relatively high speeds, and is only restricted by digital control ability. Currently, this task would take no more than 50-100 us maximum. Therefore, the global maximum in any set of rapidly changing shading conditions can be found. Importantly, however, some unsolved questions remain regarding accuracy and sustainability of this approach. The present work analyzes these essential properties and concludes with the proposed MPPT algorithm.

	NPC Three Level Inverter With Dual DC Bus For Independent Distributed Generators. Neutral-Point Voltage Balancing Under The Input Power Imbalance. By MILOSZ SZAREK	[View] [Download]
Abstract: This paper concerns the application of three-level neutral point clamped (NPC) voltage source inverter (VSI) to electrical energy conversion of the photovoltaic (PV) power plant. The grid-connected3-phase NPC inverter is powered via the split DC-link composed of the capacitive divider. It enables the usage of two DC-buses independently which can be supplied by the separated boost-typeDC-DC converters. They are used to generate the maximal power value (MPP) from each string of PV modules. The main objective of this paper is the analysis of a DC-link voltage unbalance effect anddevelopment of dedicated balancing control algorithm based on the 7-segment space vector modulation method (SVM). The goal of proposed solution is proper operation of the three-phase NPCinverter under permanent input PV power unbalance. In the presented paper the maximal permissible level of input power unbalance was estimated which can be compensated by the use ofdeveloped NPC inverter modulation method as a function of the instantaneous operation point (e.g. amplitude modulation index). The listed issues were verified via simulation research performed in Maltab\Simulink software as well as experimentally via the laboratory tests.

	Power Flow Interactive Sharing between Two DC Nanogrids Photovoltaic Local Branch Dynamic Systems at Island Operation By Maged BAUOMY	[View] [Download]
Abstract: Nowadays DC nanogrid topologies are going spread with the deployment of distributed generation. Therefore, the investigation of interactive sharing between DC nanogrid branches is mandatory to realize a continuous operation of the photovoltaic considering: maximum power tracking, Off-maximum power point tracking, load sharing, and battery charge sharing. This paper discusses the power flow interaction among two DC nanogrids in island mode. To demonstrate that, a detailed dynamic branch modeling systems is proposed. The MPPT and Off-MPPT control are tested on this nanogrid dynamic model; the MPPT is working continuously unless the two BSS are fully charged which is known by the reference indicator state of charge (SOC) value. If the BSS reaches SOC 100 \%, the Off-MPPT control will be operated to stop extraction of more power. The objective of interactive sharing is proposed by a control approach for the bidirectional converter utilized in charging and discharging of BSS. This control approach with the support of simple nanogrid controller transfers power via transmission line to performs load sharing and BSS charging of the nanogrid. The power transfer between the two buses will be performed by rising the sending bus voltage above the receiving bus.

	Single-phase transformerless PV inverter topology with AC bypass and mid-DC-link voltage clamping By GEORGIOS ORFANOUDAKIS	[View] [Download]
Abstract: Transformerless PV inverters are known to generate undesirable ground leakage currents due to the lack of galvanic isolation between the PV array and the electric grid. This paper initially discusses the different types of transformerless PV inverter topologies that have been proposed to overcome this problem. It then proposes a new topology, which extends the commercially successful HERIC inverter with the addition of a mid-DC-link clamping configuration. Such configurations are known to cause a highly desirable reduction of the ground leakage currents, which is demonstrated through simulation results from MATLAB-Simulink and PLECS. The proposed topology is finally compared to other transformerless topologies with respect to other aspects, such as efficiency and component count.