A new high-efficiency single-phase transformerless PV inverter topology Tamás Kerekes, Member, IEEE, Remus Teodorescu, Senior Member, IEEE, Pedro Rodríguez, Member, IEEE, Gerardo Vázquez, Student Member, IEEE, Emiliano Aldabas, Member, IEEE

A new high-efficiency single-phase transformerless PV inverter topology

Tamás Kerekes, Member, IEEE, Remus Teodorescu, Senior Member, IEEE, Pedro Rodríguez, Member, IEEE, Gerardo Vázquez, Student Member, IEEE, Emiliano Aldabas, Member, IEEE

ABSTRACT: There is a strong trend in the photovoltaic (PV) inverter technology to use transformerless topologies in order to acquire higher efficiencies combining with very low ground leakage current. In this paper a new topology, based on the H- Bridge with a new AC bypass circuit consisting in a diode rectifier and a switch with clamping to the DC midpoint is proposed. The topology is simulated and experimentally validated and a comparison with other existing topologies is performed. High conversion efficiency and low leakage current is demonstrated.

I INTRODUCTION Photovoltaic inverters become more and more widespread within both private and commercial circles. These grid connected inverters convert the available direct current supplied by the photovoltaic (PV) panels and feed it into the utility grid. According to the latest report on installed PV power, during 2007 there has been a total of 2.25GW of installed PV systems, out of which the majority (90%) has been installed in Germany, Spain, USA and Japan. At the end of 2007 the total installed PV capacity has reached 7.9 GW of which around 92% is grid connected [1].

There are two main topology groups used in case of grid connected PV systems and they are: with and without galvanic isolation [2]. Galvanic isolation can be on the DC side, in the form of a high frequency DC-DC transformer or on the grid side in the form of a big-bulky AC transformer. Both of these solutions offer the safety and advantage of galvanic isolation, but the efficiency of the whole system is decreased, due to power losses in these extra components. In case the transformer is omitted the efficiency of the whole PV system can be increased with an extra 1-2%. The most important advantages of transformerless PV systems can be observed in Fig. 1, like: higher efficiency, smaller size and weight compared to the PV systems that have galvanic isolation (either on the DC or AC side). 1 Fig. 1 has been made from the database of more than 400 commercially available PV inverters, presented in a commercial magazine about PV systems [3]. Transformerless inverters are represented by the dots (Transformerless), while the triangles represent the inverters that have a low-frequency transformer on the grid side (LF-transformer) and last the stars represent the topologies including a high-frequency DC-DC transformer (HF-transformer), adding a galvanic isolation between the PV and grid. The conclusion drawn from these graphs is that transformerless inverters have higher efficiency, smaller weight and size than their counterparts with galvanic separation. Transformerless PV inverters use different solutions to minimize the leakage ground current and improve the efficiency of the whole system, an issue that has previously been treated in many papers [4]-[11].

LINK: http://seer.upc.edu/material/ficheros_publicaciones/26552ZRV_PV_Inverter.pdf

A Digital Control System for UPS Systems with Smart Grid Capability-Author Mardani Boroujeni, Fatemeh-Faculty Schulich School of Engineering- Institution University of Calgary

 

A Digital Control System for UPS Systems with Smart Grid Capability by Fatemeh Mardani Boroujeni

 

UNIVERSITY OF CALGARY

A THESIS SUBMITTED TO THE FACULTY OF GRADUATE STUDIES IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE GRADUATE PROGRAM IN ELECTRICAL ENGINEERING CALGARY, 

ALBERTA AUGUST, 2019.

  Abstract 

Smart grids have recently become the center of attention for modernizing the grid system. In future smart-grids, energy storage systems are one of the key components, which can complement intermittent renewable energy sources and in turn increase reliability and eciency of the grid system. Modern Uninterruptible Power Supply (UPS) systems can provide storage capacity for future smart grids since they usually include batteries. UPS systems can also provide instant electrical power to sensitive equipment and grid during various events such as brownout, power failures, spikes, voltage surges, EMI/RF noise, and frequency variations.

Future UPS systems require to have much better dynamics in order to deal with transients. The control system of UPS systems mainly determines their dynamical performance and transient response. The existing state-of-the-art UPS control systems are based on linear PI controllers for the most part. Thus, current UPS systems usually show a sluggish transient response and they are not suited for future smart grid applications where instant power is required to maintain the system.

In this thesis, new UPS systems with improved transient response are proposed. The proposed UPS system utilities a new controller that is able to improve the dynamic performance and allows for various smart grid functionalities. The proposed control system is based on the adaptive control theory, which adaptively changes the controller's parameters based on the UPS operating conditions. Furthermore, the proposed control system isolates the double-frequency ripple from the battery in the normal/charging mode as well as in the backup/discharging mode. Therefore, the new UPS system is well-suited for single-phase systems utilizing lithium-ion battery as storage. Mathematical analysis, simulation, and experimental results are presented to verify the performance of the proposed control system and demonstrate its superior performance.

LINK:https://prism.ucalgary.ca/bitstream/handle/1880/110715/ucalgary_2019_mardaniboroujeni_fatemeh.pdf?sequence=2&isAllowed=y

Conception et optimisation d’ Alimentations Sans Interruption-THÈSE Pour obtenir le grade de DOCTEUR DE LA COMMUNAUTE UNIVERSITE GRENOBLE ALPES Spécialité : Génie Electrique--Présentée par « Mahmoud IBRAHIM »

 

Conception et optimisation d’Alimentations Sans Interruption THÈSE Pour obtenir le grade de DOCTEUR DE LA COMMUNAUTE UNIVERSITE GRENOBLE ALPES

Spécialité : Génie Electrique Arrêté ministériel : 7 août 2006 Présentée par « Mahmoud IBRAHIM »

Thèse dirigée par Jean-Paul FERRIEUX Co-encadrée par David FREY et Pierre LEFRANC préparée au sein du Laboratoire de Génie Électrique de Grenoble (G2Elab) dans l'École Doctorale Électronique, Électrotechnique, Automatique et Traitement du Signal (EEATS)

Résumé La conception des Alimentations Sans Interruption (ASI) a fait l’objet d’améliorations successives ces dernières années afin d’atteindre des niveaux de rendement avoisinant les 95% tout en minimisant leur encombrement. L’utilisation massive de l’électronique de puissance pour ces systèmes conduit à y concentrer tous les efforts de conception pour augmenter à la fois le rendement et la densité de puissance. Les développements constants en électronique de puissance offrent au concepteur des multitudes d’options, parmi elles, les topologies de puissance multi-niveaux et/ou entrelacées pour réduire le volume des composants passifs, les nouvelles technologies des matériaux semi-conducteurs avec l’introduction des composants grand gap, ainsi que l’avancée technologique sur les matériaux utilisés dans les composants passifs. Le choix entre ces options est un compromis pour atteindre les objectifs prédéfinis, particulièrement lorsque d’autres contraintes apparaissent pour limiter l’espace des solutions possibles, notamment l’aspect thermique, les limites technologiques ou les contraintes CEM.

Ces travaux proposent la mise en oeuvre de dimensionnements par optimisation multiobjectifs de l’ensemble du convertisseur avec toutes ses contraintes. Ceci offre un outil rapide pour comparer les différentes possibilités de conception optimale capable de quantifier le gain apporté au convertisseur par les différentes solutions. Pour ce faire, les différents choix topologiques et technologiques ont été traités par le développement de modèles multiphysiques acceptant des paramètres d’entrée discrets. Ainsi, les convertisseurs optimisés répondent naturellement aux contraintes industrielles cadrées par des catalogues de fournisseurs spécifiques.

Pour ce faire, nous avons commencé par dresser les différentes contraintes énergétiques imposées sur l’ASI dans son environnement. L’identification des solutions adaptées à sa conception est réalisée à travers un état de l’art des recherches dans le domaine de l’électronique de puissance. Des modèles génériques des structures de puissance, ainsi que des modèles multi-physiques discrets des composants sont ensuite développés à la base des approches analytiques assurant le bon compromis entre précision et rapidité de calcul. Finalement, une méthodologie d’optimisation multi-objectif et multi contraintes est réalisé sur l’ensemble des solutions pour quantifier les performances atteintes par chacune d’elles. Des travaux expérimentaux nous ont été indispensables pour valider les modèles et les solutions optimales. Sur la base des résultats d’optimisation un convertisseur PFC de 4.2kW/L a été construit est ses performances ont été validées.

LINK:  https://tel.archives-ouvertes.fr/tel-01401407/document

Design and implementation of a GaN based dual active bridge converter for electric vehicle charger-CANDIDATE: Marco Giacomazzo-INDUSTRIAL ENGINEERING DEPARTMENT Master’s degree in Electrical Energy Engineering-University of Padua

 

Industrial Engineering Department Master’s degree in Electrical Energy Engineering

Master's thesis in Electrical Energy Engineering 

SUPERVISOR: Prof. Manuele Bertoluzzo 

CO-SUPERVISOR: M.Sc. Konstantin Siebke 

CANDIDATE: Marco Giacomazzo

 ACADEMIC YEAR 2019-2020

 Design and implementation of a GaN based dual active bridge converter for electric vehicle charger 

 Abstract

 In questa tesi si affronta lo studio del convertitore doppio ponte attivo, operante alla frequenza di 500 [kHz]; viene inoltre presentata la progettazione del trasformatore ad alta frequenza ed infine viene descritta una possibile alternativa al classico controllo con singolo sfasamento tra i due ponti attivi, al fine di estendere il funzionamento in soft switching anche con piccoli livelli di potenza trasmessa, in particolare durante l'ultimo stadio di carica della batteria.

LINK:http://www.mediafire.com/file/alauj0ohf9v15wl/Giacomazzo_Marco_1159867.pdf/file

A Study on the Efficiency Improvement of Inverter for Automotive using SiC MOSFET SiC MOSFET를 이용한 차량용 INVERTER 효율 향상에 관한 연구--KOREA NATIONAL UNIVERSITY OF TRANSPORTATION

 A Study on the Efficiency Improvement of Inverter for Automotive using SiC MOSFET

 SiC MOSFET를 이용한 차량용 INVERTER 효율 향상에 관한 연구 

Author

Seongki Ahn

KOREA NATIONAL UNIVERSITY OF TRANSPORTATION

Abstract 

DC-AC inverter units for vehicles are supplied with input voltage DC 12V to 24V using vehicle batteries and converted to single phase AC 220V. Automotive DC-AC inverters have been used in some places with generators where electricity cannot be drawn up, such as election campaign vehicles, but they are increasingly turning into inverters due to engine noise and smoke problems in generators. In particular, the need to use AC power in camping vehicles and food trucks increased due to the influence of the five-day workweek, and the increasing use of non-starting air conditioners in large vehicles such as trailers. In addition, with the increasing use of personal electrical appliances such as laptops and mobile phones, the demand for DC-AC inverters for vehicles is expected to surge in the coming months in multi-use transportation means such as buses and railway vehicles. MOSFET, which is a power semiconductor device, is a major component that is needed for DC-AC inverters for vehicles. Although silicon (Si : Silicon) power semiconductor device has been used as a key power conversion component of inverter system until now, achieving fast/lightening and high power generation of power unit that consists of silicon element is reaching its limit. Silicon carbide (SiC : Silicon Carbide) power semiconductor is the next generation power semiconductor to replace the limit situation that Si power semiconductor has. In this paper, we measured the loss of conduction, switching loss, efficiency characteristics, and the temperature of the main parts for Si / SiC MOSFET. In the conduction loss experiment, the loss value of SiC MOSFET compared to Si MOSFET for one cycle is approximately 61.3(%). The switching loss experiment showed that SiC MOSFET losses were small, with about 49.6(%) at Turn-on and approximately 49.2(%) at Turn-off against Si MOSFET. This was immediately confirmed to be low temperature in each part of the inverter. In particular, it was found that the temperature difference at the transformer core with the highest temperature varies from the load of 600(W) to 15.1(°C). In the experiment of efficiency characteristics, the maximum efficiency of 93.5(%) was obtained, and the efficiency improvement of up to 2.8(%) compared to the inverter with Si MOSFET was achieved. The temperature measurement test also shows that most parts temperature is low in the inverter employing SiC MOSFET. The application of SiC MOSFET to the efficiency of inverter was proved to be reasonable as the performance of inverter with SiC

In this paper, we measured the loss of conduction, switching loss, efficiency characteristics, and the temperature of the main parts for Si / SiC MOSFET. In the conduction loss experiment, the loss value of SiC MOSFET compared to Si MOSFET for one cycle is approximately 61.3(%). The switching loss experiment showed that SiC MOSFET losses were small, with about 49.6(%) at Turn-on and approximately 49.2(%) at Turn-off against Si MOSFET. This was immediately confirmed to be low temperature in each part of the inverter. In particular, it was found that the temperature difference at the transformer core with the highest temperature varies from the load of 600(W) to 15.1(°C). In the experiment of efficiency characteristics, the maximum efficiency of 93.5(%) was obtained, and the efficiency improvement of up to 2.8(%) compared to the inverter with Si MOSFET was achieved. The temperature measurement test also shows that most parts temperature is low in the inverter employing SiC MOSFET. The application of SiC MOSFET to the efficiency of inverter was proved to be reasonable as the performance of inverter with SiC

LINK: http://www.mediafire.com/file/w41aw238oiejlv4/A+Study+on+the+Efficiency+Improvement+of+Inverter+for+Automotive+using+SiC+MOSFET.pdf/file