Maria Teresa Outeiro

Resonant Power Converters: An Overview with Multiple Elements in the Resonant Tank Network

Finite commutation times are associated with the concurrent occurrence of both voltage-across and current-through semiconductor switches, leading to switching power losses. To alleviate them, soft-switching techniques have been developed. Soft-switching converters can be classified into quasi-resonant and multiresonant, resonant-transition, and resonant power converters (RPCs). This article focuses on RPCs, due to their high power density and efficiency. Specifically, RPC topologies with multiple elements are described, and their input-output relationships and efficiency are illustrated. The merits and limitations of RPCs are discussed and compared. An RPC intended to charge the battery of an electric vehicle (EV) is presented, and experimental results are discussed.

Control and analysis of multi-level type multi-phase resonant converter for wireless EV charging

In this study, a multi-level type multi-phase resonant converter is presented for high power wireless EV charging applications. As an alternative to the traditional frequency and phase shift control methods, a hybrid phase-frequency control strategy is implemented to improve the system efficiency. In order to confirm the proposed converter and control technique, a laboratory prototype wireless EV charger is designed using 8 inches air gap coreless transformer and rectifier. The proposed control is compared with the conventional control methods for various load conditions at the different power levels. The experimental results show that the proposed converter is within the desired frequency range while regulating output from 0 to 15 kW with 750 V input DC bus voltage.

Performance assessment of the new remote power supply controller for the Elettra Storage Ring magnets

Among the wide range of applications that power supplies are able to cover, the Particle Accelerator based Light Sources are one of the most demanding. In the specific case of the Elettra Storage Ring, a Synchrotron Radiation Facility operating since 1993, magnet power supplies with other critical devices are determining the quality of the photon beams and overall accelerator uptime. Because of that, they have to provide stable, reliable, precise and remotely controlled operation. From a strictly functional perspective, each magnet power supply can be seen as a power part, regulating the output current, and a control part to connect the unit to the remote control system. The original Elettra magnet power supplies are still reliably in operation but their control parts, based on VME boards and MIL 1553 interfaces, need an update to cope with ageing, components obsolescence and servicing. This paper presents the laboratory and on-field performance of the NewPSC (New Power Supply Controller), the board designed at Elettra to replace the VME-based power supplies control systems in the Storage Ring.

Design, implementation and experimental validation of a DC-DC resonant converter for PEM fuel cell applications

When designing DC-DC resonant converters (RC) for PEM fuel cell applications some considerations must be fulfilled, such as; an appropriate topology, adequate control structure, accurate selection of the components namely, the power switches, heat sinks and core of each magnetic components and careful design of the HF transformer, resonant circuit and filters. The combination of all of these aspects defines the performance of the converter, hence the importance to be taken on its design. Particularly an accurate design of the RC defines its dynamics and stability. In this context, the paper is focused on the design, implementation and experimental validation of a DC-DC resonant converter for such applications. Once characterized the PEM fuel cell as electrical element of the circuit and defined the topology and control of the resonant converter its operation is analyzed based on second-order differential equation, where each one of the operation modes is treated separately. The constraints imposed by the PEM fuel cell are considered in the selection of the components, followed by the implementation of a 1kW prototype of the RC. The procedure proposed as well as the performance of the RC implemented in terms of dynamics and stability is validated by experimental results.

Resonant converters for electric equipment power supply

The paper deals with the use of resonant converters for the power supply of electric equipment. After exploring the advantages of using the resonant conversion, an analysis of the three main resonant topologies, namely i) series-resonant, ii) parallel-resonant, and iii) a combination of them, is carried out and a series resonant converter is implemented. Considerations on the design of the resonant converter as well as on the selection of their components, including the HF transformer, are presented. Performance of the implemented series resonant converter is investigated in terms of dynamic behavior through experimental results.

A soft-switching DC/DC converter to improve performance of a PEM fuel cell system

This paper presents a soft-switching dc/dc converter with ZCS to improve the performance of a PEM fuel cell as a power generation system. The first part of the paper presents an appropriate model for the fuel cell behavior based on analytical formulation of chemical processes behind fuel cell operation and the design of an equivalent and analogue electrical circuit describing the fuel cell operation. A method to extract the set of parameters needed for modeling and to optimize their values is also presented. For the validation of this approach experimental tests are performed with a commercial fuel cell system. The dynamics of the fuel cell model and the dependency on operation point are analyzed. In fact, the dynamics of the fuel cell must be taken in account for an accurate characterization of the fuel cell as a power generation unit. As a power generation unit the fuel cell must be integrated with a dc/dc converter able of controlling the system operating as a dc regulated Voltage source and controlling the fuel cell MPPT, maximizing the generated energy. Authors purpose in the second part of the paper a topology this dc/dc converter based on resonant operation, which allows a soft-switching commutation, and consequently a high efficiency operation. Analysis on selected topology choice, the control and design of the converter are performed. Carried out results show that the controller needs to have a dynamic derivative component in order to ensure a good regulation of output voltage for different load conditions and disturbances on them. The overall system is validated using Matlab/Simulink models.

Comparison of resonant power converters with two, three, and four energy storage elements

In general, analysis of Resonant Power Converters (RPCs) is more complex than conventional converters. Consequently, it is common to adopt methods that facilitate the analysis. One of them is the First Harmonic Approximation (FHA). It assumes that only the fundamental harmonic of the current/voltage quantities affects the RPC operation, thanks to the filtering action of the resonant tank network (RTN) embedded in RPCs. The RPC stages can then be represented by simple equivalent circuits with sinusoidal solicitations and the operation can be studied by the standard linear ac analysis. In this paper the characteristics of RPCs with RTN made of two, three, and four elements are investigated using the FHA method. Input impedance, voltage gain and efficiency are derived and discussed for the various topologies. Merits and limitations of the topologies are also addressed.

Considerations in designing power supplies for particle accelerators

Stringent demands must be fulfilled when designing power supplies (PSs) for particle accelerators, such as stability, efficiency, accuracy, and electromagnetic compatibility. In this context, the paper analyzes the basic requirements to be considered when designing a PS for such applications. After reviewing the main circuitry topologies used in PSs, the electrical specifications and functional modes necessary to set up high-performance PSs are addressed. Problems concerning the fulfillment of the electrical specifications are discussed, followed by an overview of the common PS control methods. Finally, the impact of some of the discussed design considerations is evaluated for the PS of the magnets of particle accelerators.

DYNAMIC MODELING AND SIMULATION OF AN OPTIMIZED PROTON EXCHANGE MEMBRANE FUEL CELL SYSTEM

Hydrogen and fuel cells are widely regarded as the key to energy solutions for the 21st century. These technologies will contribute significantly to a reduction in environmental impact, enhanced energy security and development of new energy industries. Fuel cells operating with hydrogen have the potential to contribute to the transition for a future sustainable energy system with low-CO2 emissions. In this paper a dynamic PEM fuel cell model, implemented in Matlab/Simulink, is presented. In order to estimate the PEM fuel cell model parameters, an optimization based approach is used. The optimization is carried out using the Simulated Annealing (SA) algorithm. This optimization process evolves converging to a minimum of the objective function. The flexibility and robustness of SA as a global search method are extremely important advantages of this method. A good agreement between experimental and simulated results is observed. This optimized PEM fuel cell model can significantly help designers of fuel cell systems by providing a tool to perform accurate design and consequently to improve system efficiency.Copyright

In-motion wireless power transfer: Technology, infrastructure, challenges and market scenario

In-motion Wireless Power Transfer (IM-WPT) is the ability of charging the battery of an EV while it is in motion. This paper introduces a review of IM-WPT charging. The main issuses relatted to; the technology associated, infrastructure and current challenges faced in research and the market scenario are addressed along the paper.