Benefits of the Coupled Inductors Combined Cuk-SEPIC (CI-CCS) Converter

An enhanced DC-DC converter is proposed in this paper, based on the combination of the Cuk and SEPIC converters. This converter uses a single switching node which is common to both Cuk and SEPIC energy transfer stages. The converter uses only one switch, yet provides dual outputs in the form of a bipolar DC bus with a common ground. Since the switch is grounded, a simple, non-isolated gate driver may be used. The proposed converter uses integrated magnetics cores to couple the input and output inductors, which significantly reduces the input current ripple. The new converter is referred to as the Coupled Inductors Combined Cuk-SEPIC (CI-CCS) converter

A New DC-DC Converter for Photovoltaic Systems: Coupled-Inductors Combined Cuk-SEPIC Converter

Abstract—An enhanced DC-DC converter is proposed in this paper, based on the combination of the Cuk and SEPIC converters, which is well-suited for solar photovoltaic (PV) applications. The converter uses only one switch (which is ground-referenced, so simple gate drive circuitry may be used), yet provides dual outputs in the form of a bipolar DC bus. The bipolar output from the DC-DC converter is able to send power to the grid via any inverter with a unipolar or bipolar DC input, and leakage currents can be eliminated if the latter type is used without using lossy DC capacitors in the load current loop. The proposed converter uses integrated magnetics cores to couple the input and output inductors, which significantly reduces the input current ripple and hence greatly improves the power extracted from the solar PV system. The design methodology along with simulation, experimental waveforms, and efficiency measurements of a 4 kW DC-DC converter are presented to prove the concept of the proposed converter. Further, a 1 kW inverter is also developed to demonstrate the converter’s grid-connection potential

Zero Ripple Current with Coupled Inductors in Continuous Conduction Mode under PWM Signals

This article presents a generalized analysis to explain current ripple of an m windings coupled inductor with a given coupling factor k ij for each pair of windings and then studies more in detail its use in the continuous conduction mode and with pulsewidth modulated signals. To determine the current ripple, a generalized expression of the equivalent inductance of each winding is calculated, including the influence of voltage unbalance. In the ideal case, the equivalent inductance shows that the current ripple can only become m times smaller than that with uncoupled inductors. But in the unbalanced case, some divergences of the equivalent inductance appear that are responsible for zero ripple current. The proposed generalized expressions of the equivalent inductance also describe the current ripple of the new appearing intervals due to out-of-phase signals. An easy to design condition is proposed that achieves zero current ripple in all windings but one. Experimental results are provided that validate the presented theoretical expressions under the given conditions

Bidirectional Electric Vehicles Service Integration in Smart Power Grid with Renewable Energy Resources

As electric vehicles (EVs) become more popular, the utility companies are forced to increase power generations in the grid. However, these EVs are capable of providing power to the grid to deliver different grid ancillary services in a concept known as vehicle-to-grid (V2G) and grid-to-vehicle (G2V), in which the EV can serve as a load or source at the same time. These services can provide more benefits when they are integrated with Photovoltaic (PV) generation. The proper modeling, design and control for the power conversion systems that provide the optimum integration among the EVs, PV generations and grid are investigated in this thesis. The coupling between the PV generation and integration bus is accomplished through a unidirectional converter. Precise dynamic and small-signal models for the grid-connected PV power system are developed and utilized to predict the system’s performance during the different operating conditions. An advanced intelligent maximum power point tracker based on fuzzy logic control is developed and designed using a mix between the analytical model and genetic algorithm optimization. The EV is connected to the integration bus through a bidirectional inductive wireless power transfer system (BIWPTS), which allows the EV to be charged and discharged wirelessly during the long-term parking, transient stops and movement. Accurate analytical and physics-based models for the BIWPTS are developed and utilized to forecast its performance, and novel practical limitations for the active and reactive power-flow during G2V and V2G operations are stated. A comparative and assessment analysis for the different compensation topologies in the symmetrical BIWPTS was performed based on analytical, simulation and experimental data. Also, a magnetic design optimization for the double-D power pad based on finite-element analysis is achieved. The nonlinearities in the BIWPTS due to the magnetic material and the high-frequency components are investigated rely on a physics-based co-simulation platform. Also, a novel two-layer predictive power-flow controller that manages the bidirectional power-flow between the EV and grid is developed, implemented and tested. In addition, the feasibility of deploying the quasi-dynamic wireless power transfer technology on the road to charge the EV during the transient stops at the traffic signals is proven

Convertisseurs à bobine variable pour applications de transport durables

Abstract: Power electronics converters are key components and enable efficient conversion and management of electrical energy in a wide range of applications. For vehicular use, there is an inevitable need to improve their performance and reducing their size. This is particularly important in case of powertrain DC-DC converters as they are required to have improved performance while respecting the specifications, characteristics and stringent space limitations. These objectives define research targets and a particular progress is essential in the field of passive components, semiconductor devices, converter topologies and control. At the current state of technologies, the passive components particularly the power inductors are dominant components which affect the overall volume, cost and performance of power electronic converters. Considering the aforementioned critical aspects, this thesis proposes a variable inductor (VI) concept in order to reduce the weight and size power inductors which are traditionally bulky and have fairly limited operating range. By modulating the permeability of the magnetic material, this concept enhances the current handling capability of power inductors, controls the current ripples, reduces the magnetic and switching losses, as well as the stresses applied to switching devices. Furthermore, it enables the use of smaller cores which leads to the reduction of mass and volume allowing improvements in the converter operation and its overall performance. However, to integrate it into powertrain DC-DC converters, it is fundamental, to question the design of the component itself, the selection of suitable magnetic core materials, and the control of current in the auxiliary winding and saturation management of magnetic cores. This thesis systematically addresses these different research challenges. A particular attention is paid to the experimental study of a VI prototype to demonstrate the concept on a small-scale in order to explore its viability. Subsequently a detailed characterization was developed using finite element analysis to determine the intrinsic functionality of the passive component. Furthermore, this thesis proposed an RMS current based VI design to reduce oversizing of power inductors for electric vehicles application. In this methodology, the selection of a suitable magnetic core material is a crucial step to assure smaller and efficient converters. Hence, this thesis proposes a simplified approach based on weighted property method (WPM) for an appropriate selection of magnetic core in accordance to the needs of the user. Furthermore, to validate the integration of this concept in DC-DC converter topology used in the powertrain of electrified vehicles, an affine parameterization method is used to design the control parameters and a simple management strategy is proposed to enable dynamic control of the VI. The converter control and the proposed strategy are evaluated through simulations of a complete powertrain of a three-wheel recreational vehicle. The small-scale experimental and simulations, and full-scale simulations have demonstrated an interesting capacity of the VI for improving the performance of DC-DC converters for electrified vehicles and manage the saturation of the magnetic core while reducing the size and weight of magnetic components.Les convertisseurs d’électroniques de puissance sont des composants clés de la conversion et gestion efficace de l’énergie électrique dans une large gamme d’applications. Pour des utilisations véhiculaires, il est inévitablement nécessaire d’améliorer leurs performances et de réduire leur taille. Ceci est particulièrement important dans le cas des convertisseurs à courant continu (CC) de la chaine de traction où des performances améliorées en réponse à une large gamme de variations de charge sont recherchées tout en respectant les spécificités, caractéristiques et limitation d’espace nécessaires aux véhicules électrifiés. Ces objectifs définissent une cible de recherche et en particulier des progrès sont essentiels dans le domaine des composants passifs, des dispositifs semi-conducteurs, des topologies des convertisseurs et leurs commandes pour généraliser l’utilisation de véhicules électriques. Les composants passifs, en particulier les inductances de puissance, sont des composants dominants qui affectent le volume global, le coût et les performances de ces convertisseurs d’électroniques de puissance. Compte tenu de ces aspects, cette thèse propose un concept de bobine variable afin de réduire le poids et la taille des inductances de puissance qui sont traditionnellement encombrantes et ont une gamme de fonctionnement assez limitée. En modulant la perméabilité du matériau magnétique, ce concept améliore la capacité de gestion du courant des bobines de puissance, contrôle les ondulations du courant et réduit les pertes magnétiques et par commutation, bien comme les contraintes appliquées aux dispositifs de commutation. En outre, il permet l’utilisation de noyaux plus petits, ce qui entraîne une réduction de masse et de volume, en permettant une amélioration du fonctionnement du convertisseur et de ses performances globales. Cependant, pour l’intégrer aux convertisseurs CC-CC utilisés dans la chaine de traction, il est fondamental de se questionner sur la conception du composant lui-même, la sélection du matériau magnétique, la commande du courant de l’enroulement auxiliaire et la gestion de la saturation du noyau magnétique. Cette thèse aborde de manière systématique ces différents défis de recherche. Une attention particulière est accordée à l’étude expérimentale d’un prototype de bobine variable pour faire la preuve de concept à petite échelle afin d’explorer sa viabilité. Par la suite, une large caractérisation par éléments finis a été développée pour déterminer le fonctionnement intrinsèque de ce composant passif. De plus, cette thèse propose une méthode systématique de design de bobine variable basée sur le courant RMS pour réduire le surdimensionnement traditionnellement associer aux inductances de puissance pour des applications véhiculaires. Dans cette méthodologie, la sélection appropriée du matériau pour le noyau magnétique est une étape cruciale pour garantir des convertisseurs plus petits et efficaces, donc une démarche de sélection simplifiée basée sur la méthode des propriétés pondérées pour le choix de noyau magnétique approprié au besoin de l’application a été mis au point. De plus, pour valider l’intégration de ce concept dans une topologie de convertisseur CC-CC traditionnellement utilisée dans la chaine de traction des véhicules électrifiés, une méthode de synthèse affine a été utilisée pour définir les paramètres des contrôleurs de courant et une stratégie de gestion de la saturation du noyau a été proposée pour permettre le contrôle dynamique de la bobine variable. La commande du convertisseur et la stratégie ont été évaluées par simulation d’une chaine de traction complète d’un véhicule récréatif réel. Les résultats expérimentaux à petite échelle et simulations à pleine échelle ont démontrés des capacités intéressantes de cette bobine variable pour l’amélioration des performances des convertisseurs CC-CC, ayant la capacité de gestion de la saturation du noyau magnétique tout en réduisant la taille et le poids de ces composants passifs, dans le but de son utilisation dans la chaine de traction des véhicules électrifiés

Capacitive power transfer for maritime electrical charging applications

Wireless power transfer can provide the convenience of automatic charging while the ships or maritime vehicles are docking, mooring, or in a sailing maneuver. It can address the challenges facing conventional wired charging technologies, including long charging and queuing time, wear and tear of the physical contacts, handling cables and wires, and electric shock hazards. Capacitive power transfer (CPT) is one of the wireless charging technologies that has received attention in on-road electric vehicle charging applications. By the main of electric fields, CPT offers an inexpensive and light charging solution with good misalignment performance. Thus, this study investigates the CPT system in which air and water are the separation medium for the electrical wireless charging of small ships and unmanned maritime vehicles. Unlike on-road charging applications, air or water can be utilized as charging mediums to charge small ships and unmanned maritime vehicles. Because of the low permittivity of the air, the air-gapped capacitive coupling in the Pico Farad range requires a mega-hertz operating frequency to transfer power over a few hundred millimeters. This study examines an air-gapped CPT system to transfer about 135 W at a separation distance of 50 mm, a total efficiency of approximately 83.9%, and a 1 MHz operating efficiency. At 13.56 MHz, the study tested a shielded air-gapped CPT system that transfers about 100 W at a separation distance of 30 mm and a total efficiency of about 87%. The study also examines the underwater CPT system by submerging the couplers in water to increase the capacitive coupling. The system can transfer about 129 W at a separation distance of 300 mm, a total efficiency of aboutapproximately%, and a 1.1 MHz operating efficiency. These CPT systems can upscale to provide a few kW for small ships and unmanned maritime vehicles. But they are still facing several challenges that need further investigations

Design and Control of Power Converters 2019

In this book, 20 papers focused on different fields of power electronics are gathered. Approximately half of the papers are focused on different control issues and techniques, ranging from the computer-aided design of digital compensators to more specific approaches such as fuzzy or sliding control techniques. The rest of the papers are focused on the design of novel topologies. The fields in which these controls and topologies are applied are varied: MMCs, photovoltaic systems, supercapacitors and traction systems, LEDs, wireless power transfer, etc

Power Electronics and Energy Management for Battery Storage Systems

The deployment of distributed renewable generation and e-mobility systems is creating a demand for improved dynamic performance, flexibility, and resilience in electrical grids. Various energy storages, such as stationary and electric vehicle batteries, together with power electronic interfaces, will play a key role in addressing these requests thanks to their enhanced functionality, fast response times, and configuration flexibility. For the large-scale implementation of this technology, the associated enabling developments are becoming of paramount importance. These include energy management algorithms; optimal sizing and coordinated control strategies of different storage technologies, including e-mobility storage; power electronic converters for interfacing renewables and battery systems, which allow for advanced interactions with the grid; and increase in round-trip efficiencies by means of advanced materials, components, and algorithms. This Special Issue contains the developments that have been published b researchers in the areas of power electronics, energy management and battery storage. A range of potential solutions to the existing barriers is presented, aiming to make the most out of these emerging technologies