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Induction heating is an efficient and high-performance heating method which already has a significant market penetration and economic impact due to its benefits inherent to contactless energy transfer systems such as quickness, cleanness, and safety. Efficiency is a key design parameter since it determines not only the appliance performance but also its environmental impact, with significant socio-political implications. However, it is not easy to determine and compare the actual power converter efficiency operating under highly variable conditions typical of IH. This paper proposes an averaged efficiency parameter elaborated based on technical and typical IH usage conditions that offers a useful value to compare power converters operating under realistic operation conditions. The proposed parameter has been evaluated in some of the most significant power converter topologies used in reported state-of-the-art induction heating systems. [ABSTRACT FROM AUTHOR]

Induction heating appliance operation is constrained by the nonlinear pot material behavior under the generated magnetic field. The equivalent load seen by the inverter varies with the intensity of the field, meaning that this variation is dependent on the mains voltage. In flexible-surface induction cooktops, this fact is combined with a high coil number and different pots to be powered simultaneously, increasing the complexity to control the transmitted power while maintaining proper mains current consumption. In this article, two noncomplementary asymmetrical modulations with in-cycle parameter variation are proposed for improved power factor correction while avoiding the need for switching frequency variation and intermodulation noise in multiload systems. The proposed strategies are analyzed and experimentally tested using a 3.6 kW multi-inverter prototype featuring five induction coils. [ABSTRACT FROM AUTHOR]

Multi-output inverters have become a key enabling technology to increase surface flexibility in domestic induction heating appliances. The most commonly used power converter topologies are based on electromechanical relays in order to multiplex the connected loads and obtain a proper heat distribution. This solution, which is used in combination with other modulations such as square waveform, relies on the thermal inertia of the pot as it needs long power-averaging periods to reduce the reiteration of the switching noise. However, it presents a significant limitation in terms of acoustic noise, reliability, and thermal performance. To overcome these limitations, complete solid-state inverters that can be operated at higher frequencies are proposed. This change in the design paradigm of the pulse density modulation strategies leads to improved thermal control in the pot and better user experience, but at the same time increases challenges due to design constraints imposed by electromagnetic compatibility regulations. This article analyzes the possibilities of a new mains-synchronized pulse density modulation applied to a flexible induction cooktop that uses a multiple-output ZVS resonant inverter topology. The feasibility of the control strategies has been tested by means of a prototype featuring 12 2-kW induction heating loads. [ABSTRACT FROM AUTHOR]

Domestic induction heating appliances have improved the final user experience due to the advantages that this technology offers, such as flexibility, fast heating, cleanness, and safety. Currently, these appliances are implemented using several isolated electronic boards to be able to be powered from one or several mains phases, enabling their use in regions with different connections. In order to enhance this approach, a multiphase power factor correction rectifier is proposed in this article, improving significantly induction heating cookers. The topology is described, and a wide variety of modulation strategies are presented and analyzed, discussing their main advantages and disadvantages according to the conduction mode, operating frequency, switching mode, and control strategy. In order to validate this proposal, an 11 kW and up-to three-phase high power-density converter for domestic induction heating applications is implemented and experimentally analyzed, including its main waveforms and efficiency. Finally, a comparative evaluation is performed to enable the selection of the optimum modulation strategy for each specific application. [ABSTRACT FROM AUTHOR]

Nowadays, several applications of electroporation have been adopted in cancer therapy with promising results that have boosted research interest. To develop new treatment options, the development of electroporation models and measurement method in order to study the real distribution of the electric field potential are needed. Nowadays, current trends in electroporation techniques suggest the use of more powerful pulse generators that enables the treatment of larger tissue volumes. However, new challenges arise regarding the modeling of the electroporation process in large tissue volumes as well as the potential thermal effects when large amounts of energy are used. The aim of this paper is to propose a finite element analysis (FEA) based model using COMSOL of the irreversible electroporation process considering both electrical and thermal effects, and to validate it through in-vivo experimentation. Moreover, we propose a methodology for measuring the electrical potential in different points of a biological tissue during the application of a train of pulses to measure the distribution of the electric field inside the tissue. For this application, needle-based electrodes have been developed to achieve the least invasive measurement possible. These tools are aimed to improve the application of the electroporation treatment by reducing its side effects. [ABSTRACT FROM AUTHOR]

Industrial induction heating (IH) is a key manufacturing process due to its benefits in terms of efficiency, accurate output power control, and high performance. These features have made possible the extension of this technology to a wide range of industries from automotive to aeronautic, domestic, or renewable energies. One of the main challenges still present is the design of a high-performance and cost-effective process for those induction targets with complex geometries exposed to the magnetic field, being the most representative example gears present in most mechanical systems. Usually, in order to optimize the heating process, multifrequency IH systems are used, being often expensive and/or difficult to tune and control. The aim of this paper is, consequently, to propose a family of power converters able to supply the inductor system with two simultaneous frequencies in order to improve the heating process of the induction target. The proposed converter takes advantage of a multiresonant network allowing full control of the output power delivered at each frequency and, at the same time, a compact and cost-effective implementation. The proposed converter is analyzed, designed, and implemented, and experimental verification of its operation is provided in this paper. [ABSTRACT FROM AUTHOR]

Flexible cooking surfaces represent the most innovative and high-performance induction heating appliances nowadays. This paper presents a multiple-output resonant inverter for multicoil systems featuring high efficiency and flexible output power control for modern induction heating appliances. By adopting a matrix structure, the number of controlled devices can be significantly reduced while high control versatility is ensured. The proposed converter is first analyzed and, in order to prove the feasibility of the proposal, a multiple-output prototype is designed and implemented. The experimental results prove the correct converter operation and output power control with multiple induction heating loads, validating the proposed approach. [ABSTRACT FROM AUTHOR]

Resonant power conversion provides high-efficiency and high-power-density power converters that have boosted the performance of many applications, including induction heating (IH). One of the main challenges of such converters is the fine tuning and operation monitoring of the resonant tank, especially when it is highly variable. This paper proposes an field-programmable gate array (FPGA)-based load identification technique based on measuring the resonant capacitor voltage and calculating its spectral components. This approach proposes an accurate and cost-effective implementation, since the sensing, conditioning, and analog-to-digital conversion systems can be significantly simplified to a single low-harmonic-content signal. The proposed approach has been tested using a wide range of IH loads and operating conditions, proving the feasibility of this proposal. [ABSTRACT FROM AUTHOR]

Induction heating is nowadays a key technology due to its advantages in terms of performance and efficiency, which has boosted its adoption in industrial, domestic, and medical applications, among others. Recent developments in domestic induction heating are focused on flexible cooking surfaces with higher output power. The design requirements of this cooktops are more restrictive due to electromagnetic compatibility (EMC), power density, efficiency, control complexity, and cost. In order to overcome these issues, the use of active power factor corrector (PFC) rectifiers is proposed. This paper proposes and analyzes a complete set of modulation strategies for a single-phase boost-type PFC applied to domestic induction heating. A comparative analysis is performed taking into account the device stress, efficiency, operating frequency, control complexity, and EMC performance. This discussion reveals the advantages and disadvantages of each modulation strategy according to the final implementation requirements and the application area. [ABSTRACT FROM AUTHOR]

Induction heating has become the most advance heating process due to benefits, such as efficiency, performance, cleanness, and safety. In this process, the electromagnetic coupling between the induction coil and the induction target is a key, determining the heating performance as well as the resonant power converter operation. This letter proposes an accurate and cost-effective resonant tank identification method applied to induction heating systems. It is based on monitoring the resonant capacitor voltage in order to calculate the resonant tank quality factor. The proposed methodology has been tested using a versatile power electronics test bench applied to domestic induction heating, proving the feasibility of this proposal. [ABSTRACT FROM PUBLISHER]

Induction heating (IH) has become the technology of choice in many industrial, domestic, and medical applications due to its high efficiency and performance. This paper proposes an interleaved resonant boost inverter featuring SiC three-phase module to achieve high efficiency and performance IH power supply. The proposed converter achieves high efficiency by reducing the current through the devices, while the use of an interleaved full-bridge configuration reduces input current ripple and provides additional control degrees. The proposed converter has been designed, implemented, and tested experimentally, proving the feasibility of this proposal. [ABSTRACT FROM PUBLISHER]

Induction heating (IH) is a key technology in modern household appliances and industries. Modern design trends require the design of high efficiency and multiple output power converters. This paper proposes a dual-output boost resonant full-bridge topology to provide a multiple-output converter with improved performance while keeping a cost-effective performance. The proposed converter is detailed and analyzed, and several modulation strategies are proposed to obtain proper output power control. Finally, an experimental prototype is built, verifying the proper operation and performance of the proposed topology. [ABSTRACT FROM PUBLISHER]

Resonant power conversion is a key enabling technology for many high-performance and high-efficiency systems. Induction heating is an example of such systems, which outperforms conventional heating technologies, leading to a wide spectrum of industrial, domestic, and medical applications. In order to ensure the proper operation of the resonant converter, accurate converter operation monitoring techniques are required. This paper proposes an effective monitoring technique based on the measurement of the resonant capacitor voltage. The proposed monitoring system provides essential information regarding the output power, soft-switching conditions, and input voltage, while featuring a cost-effective implementation. The proposed technique is validated through an FPGA-controlled resonant power converter applied to induction heating, proving the feasibility of this proposal. [ABSTRACT FROM AUTHOR]

Induction heating technology is leading technical advances in home appliances due to the benefits inherent to the contactless energy transfer including high efficiency, fast heating, safety, cleanness, and accurate control, among others. Recent design trends are focused on developing more versatile cooking appliances for an improved user performance. To achieve such implementations, new multicoil architectures and power converters must be developed. This paper proposes the series-resonant multiinverter as an efficient, versatile, and cost-effective alternative to supply multiinductor systems. One of the main design challenges is the high blocking voltage of power devices, which may compromise the converter performance. This paper proposes an optimized modulation strategy to reduce the maximum device voltage, enabling an optimized converter design with improved reliability and performance. The proposed modulation is analytically studied and tested using a multicoil induction heating converter prototype, proving the feasibility of this proposal. [ABSTRACT FROM PUBLISHER]

This paper presents a comparative evaluation of silicon carbide power devices for the domestic induction heating (IH) application, which currently has a major industrial, economic and social impact. The compared technologies include MOSFETs, normally on and normally off JFETs, as well as BJTs. These devices have been compared according to different figure-of-merit evaluating conduction and switching performance, efficiency, impact of temperature, as well as other driving and protection issues. To perform the proposed evaluation, a versatile test platform has been developed. As a result of this study, several differential features are identified and discussed, taking into account the pursued induction heating application. [ABSTRACT FROM PUBLISHER]

New semiconductor technology is enabling the design of more reliable and high performance power converters. In particular, silicon carbide (SiC) technology provides faster switching times, higher operating temperature, and higher blocking voltage. Among the new SiC devices, bipolar junction transistors (BJTs) present interesting features in terms of conduction and switching losses. However, one of the main drawbacks is that these devices have low gain, requiring high base current to activate them. As a consequence, the base drive circuit becomes more complex and the final efficiency is decreased. This letter presents an optimized base drive circuit for a zero-voltage switching series resonant inverter. The proposed circuit maximizes the driver efficiency and minimizes the driver current requirements. Moreover, the proposed circuit optimizes the power converter switching conditions, increasing the converter efficiency. The proposed base drive circuit has been tested with a SiC-BJT-based series resonant inverter applied to induction heating. [ABSTRACT FROM AUTHOR]

Induction heating systems are the technology of choice in many industrial, domestic, and medical applications due to its high performance. The core component of such systems is the power supply, which is usually composed of a rectifier stage and a resonant inverter. In order to simplify and further optimize the performance of the power supply, a class-E direct ac–ac converter featuring multicycle modulations is proposed in this paper. The proposed converter is composed of two switching devices that enable the direct ac–ac conversion. Single- and multicycle operation modes have been analytically described to prove the benefits, in terms of peak voltage reduction and output power control capabilities. A prototype featuring SiC junction-gate field-effect transistor devices, which perfectly fit these applications, has been designed and built to prove the feasibility of the proposed converter. The experimental results match the analytical results and validate the benefits of this converter. [ABSTRACT FROM PUBLISHER]

Domestic induction-heating technology requires specific features such as high output power levels in a reduced enclosure, elevated operating temperature, large load variation, and reduced cost. To fulfill these requirements, classical solutions are based on the combination of a rectifier and a dc-link inverter. This is a well-balanced solution, but there is still room for efficiency and cost improvements. Unlike previous proposals, this paper proposes a direct ac–ac converter to reduce the component count, reduce cost, improve reliability, and increase efficiency. The proposed converter is a voltage-source series-resonant converter that achieves linear output power control, reducing control complexity. Moreover, the proposed converter achieves soft switching during both turn-on and turn-off transitions, further improving the efficiency and enabling the selection of low-speed devices with improved conduction properties. A 3.6-kW converter has been designed and implemented, verifying the feasibility of the proposal and the expected performance. [ABSTRACT FROM PUBLISHER]

Efficiency is a key design parameter when designing the power converters for domestic induction heating applications, since it determines not only the environmental impact of the power converter but also its final performance and reliability. In this paper, the design of high-efficiency converters for induction heating applications is discussed, focusing on the advantages of using wide bandgap devices. As a conclusion, a multiple-output boost resonant ac-ac converter is proposed, significantly improving current state-of-the-art efficiency and achieving a reduced component-count solution for multiple-load systems. The proposed converter has been tested through a dual-output boost resonant inverter for domestic induction heating applications. The design procedure is detailed, including the design of an optimized gate drive circuit for this application. Experimental results show significant improvements in efficiency in the whole operating range, and an accurate output power control, proving the benefits and feasibility of the proposed SiC-based converter. [ABSTRACT FROM AUTHOR]

Domestic induction heating (IH) is currently the technology of choice in modern domestic applications due to its advantages regarding fast heating time, efficiency, and improved control. New design trends pursue the implementation of new cost-effective topologies with higher efficiency levels. In order to achieve this aim, a direct ac–ac boost resonant converter is proposed in this paper. The main features of this proposal are the improved efficiency, reduced component count, and proper output power control. A detailed analytical model leading to closed-form expressions of the main magnitudes is presented, and a converter design procedure is proposed. In addition, an experimental prototype has been designed and built to prove the expected converter performance and the accurateness of the analytical model. The experimental results are in good agreement with the analytical ones and prove the feasibility of the proposed converter for the IH application. [ABSTRACT FROM AUTHOR]

Domestic induction appliances require power converters that feature high efficiency and accurate power control in a wide range of operating conditions. To achieve this modulation techniques play a key role to optimize the power converter operation. In this paper, a series resonant inverter featuring reverse-blocking insulated gate bipolar transistors and an optimized modulation technique are proposed. An analytical study of the converter operation is performed, and the main simulation results are shown. The proposed topology reduces both conduction and switching losses, increasing significantly the power converter efficiency. Moreover, the proposed modulation technique achieves linear output power control, improving the final appliance performance. The results derived from this analysis are tested by means of an experimental prototype, verifying the feasibility of the proposed converter and modulation technique. [ABSTRACT FROM PUBLISHER]

This paper presents the analysis and design of a new ac-ac resonant converter applied to domestic induction heating. The proposed topology, based on the half-bridge series resonant inverter, uses only two diodes to rectify the mains voltage. The proposed converter can operate with zero-voltage switching during both switch-on and switch-off transitions. Moreover, this topology doubles the output voltage, and therefore, the current in the load is reduced for the same output power. As a consequence, the converter efficiency is significantly improved. The analytical and simulation results have been verified by means of a 3600-W induction heating prototype. An efficiency study has been carried out, obtaining values higher than 96%. [ABSTRACT FROM AUTHOR]

Modern induction heating systems involve usually many non-linear systems with different constraints, making difficult implementing classical controllers. In this context, model predictive control arises as a powerful technique able to provide high performance controllers with advanced functionalities. This paper will discuss the benefits of this control technique for induction heating systems and will provide an example of application for domestic systems. As a conclusion, MPC will help powering future induction heating systems with improved control capabilities and performance. [ABSTRACT FROM AUTHOR]

The article presents a conversation between researchers Hector Sarnago and Oscar Lucia regarding their study entitled "Optimal Gate Drive Circuit Design for the ZVS operation of SiC JFET devices." Topics discussed include the Group of Power Electronics and Microelectronics (GEPM), the importance of implementation of induction heating appliances, and the role of the study for improvement of performance of of heating appliances.

Thermal management is a key design aspect of power converters since it determines their reliability as well as their final performance and power density. Cooling technologies have been a research area in electronics since the 1940s and, in the last 15 years, the number of articles related to this field has grown significantly. At present, thermal management is essential in new disciplines and it is a critical enabling technology in the development of power electronic systems. This paper aims at presenting a review of the state-of-the-art technology and provides future design guidelines for high efficiency power electronic converters. The main design trends are focused on the need to develop cooling systems able to manage high local density heat fluxes due to two converging trends: higher power dissipation and smaller module size. Considering the latest advances in thermal management, as well as the huge improvement in power electronics in the last decades, a review and classification of the main thermal management techniques is presented. Besides, they are compared considering important parameters such as peak power dissipation, efficiency, cost/complexity, power density or technical maturity, and a design example for an ultrahigh efficiency converter is presented. [ABSTRACT FROM PUBLISHER]

Litz wire has been widely utilized in power transformers and inductors as a wire with low copper loss at high-frequency operation. The Litz wire is commonly made of many thin isolated strands twisted in multiple levels. Due to its complicated structure, the copper loss prediction of the Litz wire has been difficult, hindering the design optimization of the Litz wire structure. To overcome this difficulty, preceding studies have investigated the analytical copper loss models of the constituting elements of the Litz wire, i.e., the strands and the bundles of strands. The purpose of this article is to propose an analytical copper loss model of the Litz wire by utilizing these preceding knowledge. The proposed model is formulated only with parameters that can be measured by basic testing instruments. Besides, the proposed model considers the bundle structure of the Litz wire, which affects the local ac current distribution, and the twisting pitch, which causes the inclination of the Litz wire strands. The proposed model was tested by comparing the analytical prediction and experimental measurements of the ac resistance of commercially available Litz wires. As a result, the predicted ac resistance showed good agreement with the measured ac resistance, suggesting the appropriateness of the proposed model. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this work is to assess the ability of sine waves to perform electrochemotherapy (ECT) and to study the dependence of the frequency of the applied sine wave on the treatment efficacy. Methods: A subcutaneous tumor model in mice was used, and the electric field was delivered in combination with bleomycin. Sinusoidal electric fields of different frequencies, amplitudes, and durations were compared to square waves. Computer simulations were additionally performed. Results: The results confirmed the ability of a sinusoidal electric field to obtain successful ECT responses. A strong dependence on frequency was obtained. The efficacy of the treatment decreased when the frequency of the sine waves was increased. At low sinusoidal frequency, the efficacy of the treatment is very similar to that obtained with a square wave. The collateral effects such as skin burns and muscle contractions decreased for the highest frequency assayed. Conclusion: The use of sine wave burst represents a feasible option for the treatment of cancer by ECT. Significance: These results could have important implications for the treatment of cancer in the clinical world where ECT is performed with dc square pulses. [ABSTRACT FROM AUTHOR]