Induction heating provides an excellent tool towards homes decarbonization, enabling efficient heating using electricity, and fostering the deployment of environmentally-friendly energy sources. To compete with other alternative heating home appliances, efficient and cost-effective implementations are required.Classical induction heating appliances use the half-bridge series-resonant inverter topology due to its good performance. However, it implies a costly implementation and complex control, leading to a high total implementation cost. When cost reduction is required, the single-switch quasi-resonant topology is used, at the cost of reduced performance and poor multi-load control. In this paper, a multi-load back-boost inverter topology is proposed. This topology reduces the number of required elements and provides a multi-inductor implementation, making it suitable for home appliances. In this work in progress paper, the proposed topology is detailed, as well as some preliminary experimental results.

Due to the growing use of the popular wireless power transmission (WPT) technology, an innovative method of coil design and optimization is presented in this paper. This method has been applied to develop spiral printed circuit board (PCB) coils with litz-wire structure. From the geometry definition, the design process is carried out by means of finite element analysis (FEA). In addition, as a complement to the design process, some prototypes of spiral PCB coils were built to contrast the simulation results and experimental measurements by means of the small-signal characterization, which reflects the success of the applied method.

One of the most important factors in the development of a home appliance is the safety of the users. For this reason, the temperature control and the protection against human errors, such as the abandonment of the cookware while cooking, are always of interest in induction heating applications. This paper presents a solution for self-limiting the temperature in cooking vessels that prevents its overheating, protecting the system and preventing food from burning. It is proposed the manufacture of cookware with materials whose electromagnetic properties change at a preset temperature within the range of interest in cooking, these changes cause the power transmitted to the load to drop considerably providing self-protection capabilities against overheating. This solution does not require additional sensors or communication with the induction cooktop, making it a simple and economical option. The performance of the proposed solution has been analyzed using a multiphysics tool, which includes electromagnetic and thermal submodels, and allows to obtain the temperature distribution and the changes in the system as the vessel heats up. Finally, an experimental verification of the model and the solution has also been presented.

Induction heating has become the most relevant domestic heating technology due to its accurate power control, clean operation and high efficiency. Current design tendencies aim to reduce limitations in pot positioning to increase the cooktop versatility and to improve the user experience. These desired flexible surfaces are implemented by means of multi-coil structures which require the design of new multi-output power converters. This paper reviews and classifies the different inverters proposed in the literature to power multi-coil structures, and analyzes them in terms of versatility, performance, and component count.

Electroporation is a phenomenon that consists on increasing the permeability of the cell membrane as a consequence of the application of an electric field. There are many applications of electroporation, but one of the most widespread at present is its clinical application to cancer treatment. This type of application requires very homogeneous treatments to ensure complete tumor removal and avoid tumor relapse. This can be achieved by ensuring an homogenous electric field application as well as optimal orientation of the electric field. However, biological tissue is composed of multiple structures and, consequently, the final electric field distribution is difficult to predict. In order to overcome this challenge, this paper proposes the use of alternating directions of the electric field in order to ensure homogeneous treatment. Additionally, classical needles and parallel plates electrodes, and power converter design requires repositioning electrodes pairs after each application in order to cover a larger area, increasing the treatment time and possible side effects. In this paper, a new multi-electrode matrix configuration is proposed to simplify the application procedure. A strategy for optimum electric field pattern application is studied, and it will serve as the basis for future experimental application using a newly developed power converter.

Cost-effective multi-output resonant inverter topologies are a key enabling technology for the development of flexible surfaces for induction heating appliances. These topologies present several challenges when applied to a wide range of IH-loads simultaneously. In this paper, two asymmetrical modulations are proposed as an alternative solution to control output power. The proposed approach has been verified using an experimental prototype featuring 2 induction heating loads up to 3.6 kW with output power control in the whole operating range.

This paper introduces the design of a three inductor system that uses a combination of induction heating and wireless power transfer, called inductively coupled heating, in order to heat an additional zone while feeding only one of the inductors. Since no more degrees of freedom are added, the delivered power to the second zone is entirely dependant on the system's geometry and resonant capacitors. Therefore, the ratio of the delivered power to each of the zones becomes very relevant to the design. A finite element model is used to simulate the magnetic fields generated by inductor currents and calculate the impedance matrix. With the impedance, capacitor values are selected with the objective of achieving a high power ratio between the second and first zone, as well as minimizing stress in the electronics. A prototype was used to validate the impedance results.

This work introduces a design method for dual wireless energy transfer and induction heating, allowing for more flexibility in features and usability. A parameterized finite element model is used, along with the development of the analytic equations that rule the system in order to determine its most relevant characteristics. Parametric studies are carried out with this model in order to understand the behavior of the system and achieve a suitable design. This is determined by the calculation of the power factor and supplied power to the system according to the frequency. The representation of these results helps determine the viability of each possible design, choosing one to develop a prototype. The validity of the method is tested via experimental measurements in small signal regime and real operation signal conditions.

Recent design trends for induction heating appliances are leading to higher power burners that offer unprecedented performance levels to the user. However, this evolution is usually constrained by the maximum power that can be drained from the mains, which is usually limited by the maximum current per phase. To overcome this limitation, the design of multi-phase converters is tackled to increase the maximum power available, being therefore needed the design of power factor corrector stages. This paper proposes therefore the design and analysis of a single-phase active power factor corrector converter to fulfill EMC standards for induction heating appliances. The proposed converter is thoroughly analyzed and designed, and will be taken as a base point for the high-power three-phase implementation. The proposed converter is experimentally verified powering an induction heating load working at constant frequency with ZVS switching conditions, providing a high-performance implementation.

This paper presents a design method for domestic induction systems whose winding is considerably farther from its load. To this end, a parametrized finite element model is used to ascertain the system's parameters. This model is used to test variations in frequency, inductor-load distance and inductor diameter. From simulation results, efficiency, output power, power loss volumetric density and near field measurement predictions are obtained. Graphical representation of these results is used to determine viability of each possible design, choosing one to develop a prototype. Validity of the model is confirmed by experimental tests in small and operating signal regimes.

Home appliances are responsible of a significant part of residential energy consumption and have a major impact in the overall energetic system efficiency. Most of them perform an indirect ac-dc-ac conversion in order to obtain the required output voltage level and frequency, depending on the applications. Thus, a high-efficiency and power density converter is required for this application where cost-effectiveness is mandatory. This paper presents an intermediate dc-dc converter intended to optimize the performance of such appliances. The proposed topology do not require an inductance, increasing its power density and efficiency, and reducing the overall converter cost. Besides, it has a fixed voltage conversion ratio requiring no complex closed-loop control and can operate both in buck and boost modes with high efficiency in the whole operating range. The performance of the proposed converter has been tested through a 2200 W prototype intended to be integrated in an induction heating appliance, proving the good performance in terms of power density and efficiency in the entire operating range.

PCB technology provides an alternative to conventional Wireless Power Transfer (WPT) coils made of wound copper wire. The most common wires for conventional coils are either a single wire or a multistranded cable conforming a litz wire structure. On the other hand, the implementation on printed board is suitable for medium-low power applications, presenting advantages as low cost, high repetibility and compact design. Moreover, for reduced losses, the litz wire structure can be adapted to a PCB implementation. In this paper, a mathematical description of the PCB litz structure is presented together with a method to automatically generate PCB layouts of custom coils. Following this method, several prototypes were built and tested. The experimental characterization of the samples shows that coils with PCB litz structure present reduced losses.

Sources of the power losses in inductor systems for induction heating home appliances are described in this paper. Energy efficiency is one of the main concerns in the design of this kind of components, thus, the power losses estimation based on computational methods constitutes a powerful tool to achieve optimal results. However, classical model neglects the contribution of the power losses in the flux concentrator usually made of ferrite. This work is focused on the assessment of the importance of this contribution with the support of numerical simulations performed in COMSOL®. Finally, the power losses in the ferrites carried out from the simulation are compared to the total power consumption of the induction heating system in order to determine the importance of the power losses in the flux concentrators.

Induction heating has evolved in recent years towards flexible cooking surfaces with multiple control possibilities. This paper reviews the series resonant multi-inverter topology as a versatile and cost-effective solution for multi-load induction heating systems and analyzes pulse density modulated control strategies with a special focus on the EMC behavior. The main control strategies are explained and the main experimental results are presented using a 9-load 3.6 kW inverter.

Magnetic hyperthermia is a promising cancer treatment technique based on selectively heating cancer cells to cause their death using the induction heating principles. In order to optimize the magnetic field generator, this paper proposes the design of a high-frequency high-power density inverter taking advantage of the recently developed high-voltage GaN devices and using an insulated metal substrate PCB for proper thermal management. The proposed converter is designed and implemented, showing its feasibility for the proposed application and enabling advanced treatments and an increased equipment portability.

Electroporation phenomenon is the basis for a number of biomedical techniques. High level electroporation, in the irreversible form, has been clinically demonstrated for treatment of solid tumors. There are few experimental available systems capable of generating at the same time the required pulse shaping, power, voltage and output impedance characteristic. In contrast power pulse generators have been a subject of study for many years applied to other fields. Nevertheless there are a few references on high voltage pulse generation oriented to electroporation and even fewer applied to clinical electroporation. This paper examines the differential characteristics of the pulse generators that would fit in an electroporation application. A detailed review and groping of power converter topologies applied to power pulse generation is incorporated. The more relevant topologies for power pulse generation, which would be suitable for clinical electroporation, are analyzed. The advantages and drawbacks of those types are highlighted from the point of view of this application. As result the discussion includes a number of conclusions about the most interesting topologies for future developments in this application.

In this paper, the efficiency of the induction system composed of 4 small coils with a given connection among them for cooking applications is analyzed. The 4-coil configuration has several advantages with respect to the single-coil induction system, for instance, higher flexibility and better heat distribution in the pan. Different configurations can be arranged according to series or parallel connections of the coils and the polarity of the currents. However, the selected configuration connection has a direct impact on the efficiency of the power transference into the pot. Therefore, in this work the efficiency of the different 4-coil configurations is analyzed. The analysis is carried out in terms of equivalent impedances. The experimental test based on impedance measurements is performed to verify the preceding analysis.

The series resonant multi-inverter topology has proved to be effective versatile and cost-effective solution to implement multi-coil induction heating cookers. A high power density prototype, which can supply nine induction loads, has been designed to check the last progress and researches in this field. In order to measure the main parameters of the converter, the prototype has a monitoring system. A communication system allows getting the measurements and to change the modulation and control strategies from PC. In addition, the developed prototype has made possible the fast development of some application examples such as pot detection and power control.

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 advances are aimed at developing high efficiency and performance converters that allows improving current applications and enabling new applications of induction heating. This paper proposes an ultra-high-efficiency class-DE converter that enables tracking the converter optimum operation point regardless the operating and load conditions. The proposed converter is described and analyzed, and its feasibility is proved by means of a domestic induction heating prototype.

Adaptable cooking surfaces are at the forefront of design trends because of the many advantages offered to users. These improvements and advantages have their counterpart in the increased design challenges related to inductors and power electronics. Shifts in the relative position between the pan and the inductor may cause the inductor to be totally or partially uncovered, leading to changes in the power converter operation. Currents and power losses can reach unacceptable levels and even damage the power converter. Experimental measurements have been realized to characterize the problem when using different materials and switching frequencies. A Matlab-GUI based interface has been designed to help the analysis of results. Static and dynamic simulation results are shown and an experimental verification has been performed. As a result, the proposed tool proves to be an effective method to analyze and improve the power converter operation under induction load variations.

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 advances are aimed at developing more versatile cooking surfaces for a superior user performance. In order to achieve such designs, new multiple-output power converters must be developed. The series resonant multi-inverter has been proposed as an efficient, versatile and cost-effective alternative to supply multi-inductor systems. However, several design challenges must be faced, including the required high blocking voltage of power devices, which may compromise the converter performance. This paper proposes an optimized modulation strategy to reduce this voltage, enabling an optimized converter design with improved reliability and performance. The proposed modulation is analytically studied and tested using an induction heating converter prototype, proving the feasibility of this proposal.

Modern power supplies must comply with strict regulations regarding efficiency and stand-by mode consumption. Thus, efficiency optimization in the whole operating range is mandatory and becomes a major design challenge, being specially difficult when both heavy and light load conditions must be addressed. This paper proposes an improved gate drive circuit to adapt the gate voltage to the load conditions. Thus, an optimum tradeoff between conduction and gating losses can be found, optimizing the power converter efficiency in the entire operating range. An efficient and cost effective implementation is proposed and tested, proving the feasibility of the proposed approach.

Domestic induction heating enables the pot to be heated directly, reducing heating times and avoiding high-temperature points, increasing safety and cleanliness in the cooking process. In addition, the energy consumption is minimized, reducing the environmental impact. To achieve this, a high frequency current generator is necessary in order to generate the required ac-magnetic field. The efficiency of this electronic converter determines the efficiency of the application, requiring therefore high efficiency power converters. Recent advances in power semiconductor technology, with particular emphasis on wide band gap devices, have allowed new converters with improved efficiency levels. In this paper, these converters will be introduced and comparative evaluation is performed. A special emphasis effort has been made for compare the different issues related with its operation and reliability, including efficiency levels, power losses distribution, and voltage and current stress levels. Finally, the effect of the wide band-gap devices on the conversion efficiency has been evaluated.

Switched-mode power supplies applied to induction heating provide conditioned power to a wide range of loads. One of the main issues in the design of these systems is the identification of the main characteristics of the load, i.e. electrical equivalent, as it to be modeled by means of a reduced set of variables. This paper proposes the procedure to extract the electrical equivalent model of the inductor system composed of a coupled double concentric coil for induction heating purposes. The parameters have been obtained by means of a method based on the Fourier analysis of experimental measurement under adequate operation conditions. The equivalent model has been validated for different working conditions in order to prove the feasibility of the proposed procedure.

In this paper, an analysis of the resistance of multi-track coils in printed circuit board (PCB) implementations, where the conductors have rectangular cross-section, for spiral planar coils is carried out. For this purpose, different analytical losses models for the mentioned conductors have been reviewed. From this review, we conclude that for the range of frequencies, the coil dimensions and the planar configuration typically used in domestic induction heating, the application in which we focus, these analysis are unsatisfactory. Therefore, in this work the resistance of multi-track winding has been calculated by means of finite element analysis (FEA) tool. These simulations provide us some design guidelines that allow us to optimize the design of multi-track coils for domestic induction heating. Furthermore, several prototypes are used to verify the simulated results, both single-turn coils and multi-turn coils.

One of the most important features of classical induction heaters is the efficiency. Efficiency, defined as the output-input power ratio is directly related with these terms: environmental impact, the total amount of energy required in the cooking process is reduced as efficiency increases; device stress, efficiency determines the amount of dissipated power, and thus, determines the temperature stress in the electronic stage; maximum output energy, defined as the time-domain integration of the maximum output power. This concept is directly related with temperature regulations, caused by inefficiencies. The analysis of the classical domestic induction heaters reveals that efficiency can be improved by the use of the booster stages. These stages increase output voltage, reducing the required current levels for the same output power, and thus, increasing conduction efficiency in the overall power electronic scheme. A review of the state-of-the-art in boost converters applied to domestic induction heating is performed in this paper. The rectifiers, inverters, and recently studied, direct ac-ac converters have been considered in the analysis. Finally, a benchmark of the reviewed stages is performed based on two criteria: the number of active devices, directly related with cost, and the control complexity, directly related with development time and failure rate.