High-Performance and Cost-Effective ZCS Matrix Resonant Inverter for Total Active Surface Induction Heating Appliances

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

Asymmetrical Modulation Strategies for Partially Covered Inductors in Flexible Induction Heating Appliances

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

Induction heating appliance with a mobile double-coil inductor

An induction heating appliance designed to uniformly heat up metallic plates is studied in this paper. It consists of one planar inductor with two concentric coils attached to a mechanism, which allows moving the inductor under the plate while heating. This system is a possible solution for the growing concept of flexible induction cooking hobs, improving their performance in flexibility and in thermal distribution in the pans. With different combinations of motion and the selective activation of the inductor coils, any pan can be uniformly heated regardless its size or position on the hob. In this paper, we develop a thermal model to analyze the temperature distribution obtained in the pans for each diameter and strategy used. The model is solved using finite differences, and it is validated with experimental measurements. From the calculations, the best strategy for each pan diameter is obtained

Status and perspectives of the multiphysical simulation of induction kitchen plates

Індукційні плити являють собою відносно новий клас сучасної електропобутової техніки – кухонні електричні плити, які розігрівають металевий посуд вихровими струмами, які створюються електромагнітним полем частотою 20-100 кГц. Представляє значний інтерес дослідження мультифізичних (електромагнітних, теплових і механічних) процесів, що протікають в індукційних плитах в процесі їх експлуатації, а також розробка методики розрахунку і проектування їх конструктивних елементів. Отримані результати мають бути розраховані на використання в практиці конструювання побутових індукційних плит, а також у навчальному процесі для підготовки фахівців за відповідною навчальною програмою. Кількість опублікованих робіт, присвячених комп’ютерному моделюванню процесів в індукційних кухонних плитах, на багато порядків менше, ніж кількість публікацій з питань добре розвинутого чисельного аналізу мультифізичних явищ у промислових індукційних нагрівачах. У статті наведено огляд і аналіз публікацій, головним чином опублікованих у закордонних виданнях, присвячених мультифізичному комп’ютерному моделюванню електромагнітних і теплових процесів і явищ в індукційних кухонних плитах і посуді, що нагрівається. Запропоновані напрямки подальших досліджень: доцільно врахувати при застосуванні метода скінчених елементів залежності електрофізичних та теплофізичних властивостей матеріалів від температури, а також нелінійні магнітні властивості (основні криві намагніченості) феромагнітних матеріалів. Математичне моделювання розподілу зв’язаних полів доцільно розпочати у двовимірній постановці (значно більш складна тривимірна постановка та відповідне програмне забезпечення можуть бути використані пізніше для уточнення отриманих результатів).Induction cookers are a relatively new class of modern electrical household appliances – kitchen electric stoves that heat metal dishes with eddy currents generated by an electromagnetic field witha frequency of 20-100 kHz. Of considerable interest is the study of multiphysical (electromagnetic, thermal, and mechanical) processes occurring in induction cookers during their operation, as well as the development of methods for calculating and designing their structural elements. The results obtained should be intended for use in the practice of designing domestic induction cookers, as well as in the educational process for training specialists in the relevant curriculum. The number of published papers devoted to computer simulation of processes in induction cookers is many orders of magnitude less than the number of publications on the issues of well-developed numerical analysis of multiphysical phenomena in industrial induction heaters. The paper presents a review and analysis of publications, mainly published abroad devoted to multiphysical computer modeling of electromagnetic and thermal processes and phenomena in induction cookers and heated dishes. The directions for further research have been proposed: it is advisable to take into account, when applying the finite element method, the dependencies of the electrophysical and thermal properties on temperature, as well as the nonlinear magnetic properties (main magnetization curves) of ferromagnetic materials. Mathematical modelling of the distribution of coupled fields should be started in a two-dimensional formulation (a much more complicated three-dimensional formulation and the corresponding software can be used later to refine the results)

Analysis and optimization of the efficiency of induction heating applications with litz-wire planar and solenoidal coils

Optimization of the efficiency of an induction heating application is essential in order to improve both reliability and performance. For this purpose, multi-stranded cables with litz structure are often used in induction heating applications. This paper presents an analysis and optimization of the efficiency of induction heating systems focusing on the optimal copper volume of the winding with respect to different constraints. The analysis is based on the concept of a one-strand one-turn coil, which captures the dissipative effects of an induction heating system and reduces the number of variables of the analysis. An expression for the efficiency of the induction heating system is derived. It is found that, with the geometry and the other parameters of the system fixed, efficiency depends on the copper volume of the windings. In order to use this result to optimize the efficiency of an application, volume restrictions, the packing factor and the window utilization factor are also considered. The optimum frequency for an induction heating system is also studied in this work. An experimental verification for both planar and solenoidal cases is also presented

Стан і перспективи мультифізичного моделювання індукційних кухонних плит

Induction cookers are a relatively new class of modern electrical household appliances – kitchen electric stoves that heat metal dishes with eddy currents generated by an electromagnetic field with a frequency of 20-100 kHz. Of considerable interest is the study of multiphysical (electromagnetic, thermal, and mechanical) processes occurring in induction cookers during their operation, as well as the development of methods for calculating and designing their structural elements. The results obtained should be intended for use in the practice of designing domestic induction cookers, as well as in the educational process for training specialists in the relevant curriculum. The number of published papers devoted to computer simulation of processes in induction cookers is many orders of magnitude less than the number of publications on the issues of well-developed numerical analysis of multiphysical phenomena in industrial induction heaters. The paper presents a review and analysis of publications, mainly published abroad devoted to multiphysical computer modeling of electromagnetic and thermal processes and phenomena in induction cookers and heated dishes. The directions for further research have been proposed: it is advisable to take into account, when applying the finite element method, the dependencies of the electrophysical and thermal properties on temperature, as well as the nonlinear magnetic properties (main magnetization curves) of ferromagnetic materials. Mathematical modelling of the distribution of coupled fields should be started in a two-dimensional formulation (a much more complicated three-dimensional formulation and the corresponding software can be used later to refine the results).Индукционные плиты представляют собой относительно новый класс современной электробытовой техники – кухонные электрические плиты, которые разогревают металлическую посуду вихревыми токами, создаваемыми электромагнитным полем частотой 20-100 кГц. Представляет значительный интерес исследование мультифизических (электромагнитных, тепловых и механических) процессов, протекающих в индукционных плитах в процессе их эксплуатации, а также разработка методики расчета и проектирования их конструктивных элементов. Полученные результаты должны быть рассчитаны на использование в практике конструирования бытовых индукционных плит, а также в учебном процессе для подготовки специалистов по соответствующей учебной программе. Количество опубликованных работ, посвященных компьютерному моделированию процессов в индукционных кухонных плитах, на много порядков меньше, чем количество публикаций по вопросам хорошо развитого численного анализа мультифизических явлений в промышленных индукционных нагревателях. В статье приведен обзор и анализ публикаций, главным образом опубликованных в зарубежных изданиях, посвященных мультифизическому компьютерному моделированию электромагнитных и тепловых процессов и явлений в индукционных кухонных плитах и нагреваемой посуде. Предложены направления дальнейших исследований: целесообразно учесть при применении метода конечных элементов зависимости электрофизических и теплофизических свойств от температуры, а также нелинейные магнитные свойства (основные кривые намагниченности) ферромагнитных материалов. Математическое моделирование распределения связанных полей целесообразно начать в двумерной постановке (значительно более сложная трехмерная постановка и соответствующее программное обеспечение могут быть использованы позднее для уточнения полученных результатов).Індукційні плити являють собою відносно новий клас сучасної електропобутової техніки – кухонні електричні плити, які розігрівають металевий посуд вихровими струмами, які створюються електромагнітним полем частотою 20-100 кГц. Представляє значний інтерес дослідження мультифізичних (електромагнітних, теплових і механічних) процесів, що протікають в індукційних плитах в процесі їх експлуатації, а також розробка методики розрахунку і проектування їх конструктивних елементів. Отримані результати мають бути розраховані на використання в практиці конструювання побутових індукційних плит, а також у навчальному процесі для підготовки фахівців за відповідною навчальною програмою. Кількість опублікованих робіт, присвячених комп’ютерному моделюванню процесів в індукційних кухонних плитах, на багато порядків менше, ніж кількість публікацій з питань добре розвинутого чисельного аналізу мультифізичних явищ у промислових індукційних нагрівачах. У статті наведено огляд і аналіз публікацій, головним чином опублікованих у закордонних виданнях, присвячених мультифізичному комп’ютерному моделюванню електромагнітних і теплових процесів і явищ в індукційних кухонних плитах і посуді, що нагрівається. Запропоновані напрямки подальших досліджень: доцільно врахувати при застосуванні метода скінчених елементів залежності електрофізичних та теплофізичних властивостей матеріалів від температури, а також нелінійні магнітні властивості (основні криві намагніченості) феромагнітних матеріалів. Математичне моделювання розподілу зв’язаних полів доцільно розпочати у двовимірній постановці (значно більш складна тривимірна постановка та відповідне програмне забезпечення можуть бути використані пізніше для уточнення отриманих результатів)

Методика мультифізичного аналізу зв’язаних електромагнітних і теплових процесів в індукційній кухонній плиті та посуді, що нагрівається

In the paper a technique for the multiphysics numerical analysis of coupled electromagnetic and thermal fields of the induction cooker and heated dishes in 2D formulation by the Finite Element Method .is proposed. Temperature dependences of electrophysical and thermal properties of materials of considered structures as well as magnetic properties of soft magnetic materials are taken into account.В работе предложена методика мультифизического численного анализа распределения связанных электромагнитного и теплового поля индукционной кухонной плиты и нагреваемой посуды в двумерной постановке методом конечных элементов. Учитываются зависимости от температуры электрофизических и теплофизических свойств материалов рассматриваемых конструкций, а также магнитные свойства магнитомягких материалов.У роботі запропоновано методику мультифізичного чисельного аналізу розподілу зв’язаних електромагнітного та теплового полів індукційної кухонної плити та посуду, що нагрівається, у двовимірній постановці методом скінчених елементів. Враховуються залежності від температури електрофізичних і теплофізичних властивостей матеріалів конструкцій, що розглядаються, а також магнітні властивості магнітом’яких матеріалів

Infrared sensor-based temperature control for domestic induction cooktops

In this paper, a precise real-time temperature control system based on infrared (IR) thermometry for domestic induction cooking is presented. The temperature in the vessel constitutes the control variable of the closed-loop power control system implemented in a commercial induction cooker. A proportional-integral controller is applied to establish the output power level in order to reach the target temperature. An optical system and a signal conditioning circuit have been implemented. For the signal processing a microprocessor with 12-bit ADC and a sampling rate of 1 Ksps has been used. The analysis of the contributions to the infrared radiation permits the definition of a procedure to estimate the temperature of the vessel with a maximum temperature error of 5 °C in the range between 60 and 250 °C for a known cookware emissivity. A simple and necessary calibration procedure with a black-body sample is presented

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

Superconducting wireless power transfer for electric vehicles

Electric vehicles (EVs) are an important pillar for the transition towards a cleaner and more sustainable future as renewable energy can penetrate into the transportation section and act as energy storage to cope with the intermittent supply of such energy sources. EVs have recently been significantly developed in terms of both performance and drive range. Various models are already commercially available, and the number of EVs on roads increases rapidly. Rather than being limited by physical cable connections, the wireless (inductive) link creates the opportunity of dynamic charging – charging while driving. Once realised, EVs will no longer be limited by their achievable range and the requirement for battery capacity will be greatly reduced. However, wireless charging systems are limited in their transfer distance and power density. Such drawbacks can be alleviated through high-temperature superconductors (HTS) and their increased current carrying capacity, which can substitute conventionally used copper coils in the charging pads. This thesis investigates the effectiveness of wireless power transfer (WPT) systems as a whole and when HTS coils are used as well as HTS performance at operating frequencies commonly used in WPT-systems. Initially, the fundamentals of superconductivity are outlined to give some background on how such conductors can help tackle problems occurring in WPT-systems and how their behaviour can be simulated. Subsequently, key technical components of wireless charging are summarised and compared, such as compensation topologies, coil design and communication. In addition, health and safety concerns regarding wireless charging are addressed, as well as their relevant standards. Economically, the costs of a wide range of wireless charging systems has also been summarised and compared. To explore the benefits of WPT-system for EVs, a force-based vehicle model is coupled with an extended battery model to simulate the impact of wireless charging on the state of charge of the accumulator sub-system. In total, three different scenarios, i.e. urban, highway and combined driving are presented. The trade-off between having a standalone charging option versus combined dynamic (or on-road charging) and quasi-dynamic (stationary charging in a dynamic environment) wireless charging is outlined and minimum system requirements, such as charging power levels and road coverage, for unlimited range are established. Furthermore, the effects of external factors such as ambient temperature, battery age and wireless transfer efficiency are investigated. It is shown that employing combined charging at medium power levels is sufficient to achieve unlimited range compared to high power requirements for standalone charging. HTS coils show great potential to enhance the WPT-system performance with high current-carrying capability and extremely low losses under certain conditions. However, HTS coils exhibit highly nonlinear loss characteristics, especially at high frequencies (above 1 kHz), which negatively influence the overall system performance. To investigate the improvements, copper, HTS and hybrid wireless charging systems in the frequency range of 11-85 kHz are experimentally tested. Results are compared with finite element analysis (FEA) simulations, which have been combined with electrical circuit models for performance analysis. The measurements and modelling results show good agreement for the WPT-system and HTS charging systems have a much higher transfer efficiency than copper at frequencies below 50 kHz. As the operating frequency increases towards 100 kHz, the performance of HTS systems deteriorates and becomes comparable to copper systems. Similar results are obtained from hybrid systems with a mixture of HTS and copper coils, either as transmitting or receiving coils. Nevertheless, it has been demonstrated that HTS significantly improves the transfer efficiency of wireless charging within a certain range of frequencies. The AC losses occurring in HTS coils, particularly transport current loss, magnetisation loss and combined loss, at high frequencies are studied further. A multilayer 2D axisymmetric coil model based on H-formulation is proposed and validated by experimental results as the HTS film layer is inapplicable at such frequencies. Three of the most commonly employed coil configurations, namely: double pancake, solenoid and circular spiral are examined. While spiral coils experience the highest transport current loss, solenoid coils are subject to the highest magnetisation loss due to the overall distribution of the turns. Furthermore, a transition frequency is defined for each coil when losses in the copper layer exceed the HTS losses. It is much lower for coils due to the interactions between the different turns compared to single HTS tapes. At higher frequencies, the range of magnetic field densities, causing a shift where the highest losses occur, decreases until losses in the copper stabilisers always dominate. In addition, case studies investigating the suitability of HTS-WPT are proposed. Lastly, methods to reduce AC losses of HTS coils are investigated with particular focus on flux diverters, which have been used for low frequency superconducting applications but their effectiveness at high frequencies is unexplored. Therefore, the impact of flux diverters on HTS double pancake coils operating at high frequencies up to 85 kHz is researched. Various geometric characteristics of the flux diverter are investigated such as air gap between diverter and coil, width and thickness. An FEA-model was used to examine the coil and diverter losses at such frequencies and different load factors between 0.1 and 0.8. It is demonstrated that flux diverters are a viable option to reduce the coil losses even at high frequencies and the width of the coil has the biggest impact on the loss reduction. In general, flux diverters are more suitable for applications using high load factors. Lastly, the impact of the diverter in terms of magnetic field distribution above the coil and overall loss distribution in the HTS coil was examined