157 research outputs found
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
Special section on induction heating systems
This special section aims at bringing some of the most recent and interesting ideas in this area by the worldwide research community and at presenting some of the latest advancements and developments in the field of induction heating technology
Power factor correction stage and matrix zero voltage switching resonant inverter for domestic induction heating appliances
The technology of flexible cooking surfaces applied to domestic induction heating (IH) appliances offers several advantages that improve the experience of the users, not only because the safety or cleanness, but also due to the fast heating and flexibility. These cooktops have more challenging design requirements because of different mains connections, efficiency requirements, electromagnetic compatibility (EMC) standards, control complexity, and cost. In previous works, the use of a front-end power factor corrector (PFC) rectifier has been proposed to overcome these restrictions. In order to get a cost-effective implementation, this paper proposes the use of a front-end PFC stage and a matrix resonant inverter, which features zero voltage switching (ZVS), to achieve a reduced number of power devices, and get a high performance and reduced power losses in the converter. Finally, an experimental prototype with four outputs of 3.6 kW has been implemented to prove the feasibility of this proposal
Multiple-Output ZVS Resonant Inverter Architecture for Flexible Induction Heating Appliances
Flexible cooking surfaces have changed the domestic induction heating product paradigm enabling the use of a wider range of cookware materials, shapes, and positions. In order to implement such systems, multiple-output resonant inverters featuring high-performance and high-efficiency operation while achieving a cost-effective implementation are required. This paper proposes a multiple-output zero-voltage-switching resonant inverter for flexible induction heating appliances. The proposed converter features a matrix structure, enabling a cost-effective implementation with a reduced number of power devices while achieving high performance and low switching losses. It has been tested by means of an experimental prototype featuring 48 induction heating coils, proving the feasibility of the proposed approach
Induction heating converter's design, control and modeling applied to continuous wire heating
Induction heating is a heating method for electrically conductive materials that takes advantage of the heat generated by the Eddy currents originated by means of a varying magnetic field. Since Michael Faraday discovered electromagnetic induction in 1831, this phenomena has been widely studied in many applications like transformers, motors or generators' design. At the turn of the 20th century, induction started to be studied as a heating method, leading to the construction of the first industrial induction melting equipment by the Electric Furnace Company in 1927.
At first, the varying magnetic fields were obtained with spark-gap generators, vacuum-tube generators and low frequency motor-generator sets. With the emergence of reliable semiconductors in the late 1960's, motor-generators were replaced by solid-state converters for low frequency applications.
With regard to the characterization of the inductor-workpiece system, the first models used to understand the load's behavior were based on analytical methods. These methods were useful to analyze the overall behavior of the load, but they were not accurate enough for a precise analysis and were limited to simple geometries. With the emergence of computers, numerical methods experienced a tremendous growth in the 1990's and started to be applied in the induction heating field. Nowadays, the development of commercial softwares that allow this type of analysis have started to make the use of numerical methods popular among research centers and enterprises. This type of softwares allow a great variety of complex analysis with high precision, consequently diminishing the trial and error process.
The research realized in last decades, the increase in the utilization of numerical modeling and the appearance and improvement of semiconductor devices, with their corresponding cost reduction, have caused the spread of induction heating in many fields. Induction heating equipments can be found in many applications, since domestic cookers to high-power aluminum melting furnaces or automotive sealing equipments, and are becoming more and more popular thanks to their easy control, quick heating and the energy savings obtained.
The present thesis focuses on the application of induction heating to wire heating. The wire heating is a continuous heating method in which the wire is continuously feeding the heating inductor. This heating method allows high production rates with reduced space requirements and is usually found in medium to high power industrial processes working 24 hours per day.
The first chapters of this study introduce the induction heating phenomena, its modeling and the converters and tanks used. Afterwards, a multichannel converter for high-power and high-frequency applications is designed and implemented with the aim of providing modularity to the converter and reduce the designing time, the production cost and its maintenance. Moreover, this type of structure provides reliability to the system and enables low repairing times, which is an extremely interesting feature for 24 hours processes.
Additionally, a software phase-locked loop for induction heating applications is designed and implemented to prove its flexibility and reliability. This type of control allows the use of the same hardware for different applications, which is attractive for the case of industrial applications. This phase-locked loop is afterwards used to design and implement a load-adaptative control that varies the references to have soft-switching according to load's variation, improving converter's performance.
Finally, the modeling of a continuous induction wire hardening system is realized, solving the difficulty of considering the mutual influence between the thermal, electromagnetic and electric parameters. In this thesis, a continuous process is modeled and tested using numerical methods and considering converter's operation and influence in the process.Postprint (published version
Analysis, Design and Implementation of a Resonant Solid State Transformer
This thesis discusses the design of a full-bridge resonant LLC Solid State Transformer. The proposed topology uses a high-frequency transformer which helps minimizing its cost and size, and enables operating at varying load conditions. By using a resonant circuit, soft switching is achieved. Commutation techniques are discussed, namely ZVS and ZCS. Both concepts are applied on different legs of the H-bridge. Pulse frequency modulation (PFM) and Phase Shifting Modulation (PSM) are utilized to control this resonant converter. One of the requirements of this work is to achieve a tightly regulated DC bus voltage. This was shown to be achieved using the proposed controller. An experimental setup was assembled and the controller was tested, the results match the simulation and calculation results. The SST setup was tested for two different power levels. The outputs confirm the validity of the controller in feeding the load and regulating the voltage within the desired switching frequency interval, while maintaining soft switching. A thermal analysis was conducted to calculate losses, and a conversion efficiency of 97.18% was achieved. Using a high frequency transformer, a reduction in size and cost is achieved as compared to conventional low frequency transformers that usually are large in size and require more material to be assembled (copper and iron). Design requirements and limitations, the proposed control scheme, modeling and implementation, and test results are provided in this thesis
Solid-state transformers in locomotives fed through AC lines: A review and future developments
One of the most important innovation expectation in railway electrical equipment is the replacement of the on-board transformer with a high power converter. Since the transformer operates at line-frequency (i.e., 50 Hz or 16 2/3 Hz), it represents a critical component from weight point of view and, moreover, it is characterized by quite poor efficiency. High power converters for this application are characterized by a medium frequency inductive coupling and are commonly referred as Power Electronic Transformers (PET), Medium Frequency Topologies or Solid-State Transformers (SST). Many studies were carried out and various prototypes were realized until now, however, the realization of such a system has some difficulties, mainly related to the high input voltage (i.e., 25 kV for 50 Hz lines and 15 kV for 16 2/3 Hz lines) and the limited performance of available power electronic switches. The aim of this study is to present a survey on the main solutions proposed in the technical literature and, analyzing pros and cons of these studies, to introduce new possible circuit topologies for this application
Dynamic modelling and control schemes for current-source resonant converters
Versió amb diverses seccions retallades, per drets de l'editorThis thesis focuses on the control methods applied to current source resonant converters, especially in two different applications of switching power supplies and wire-less power transfer systems. In fact, the existing applications are mostly working with voltage source resonant converters. For voltage-source resonant converters, many control strategies have been analyzed and investigated, turning this into a mature technology nowadays. The current-source resonant converter is an alternative solution as they offer well-known advantages such as non-pulsating input current, low stress for switches, simple driving circuitry, and short circuit protection capabilities.
However, there is an obvious lack of control methods applicable to current-source resonant converters. In addition, obtaining an appropriate dynamic model to be used in control design is the other challenging issue in this field. Hence, the objectives of this thesis are used to fill these gaps. The proposed control schemes are:
- Frequency modulation control scheme applied to a DC/DC current-source parallel resonant converter.
- Sliding mode control scheme with amplitude modulation applied to a DC/DC current-source parallel resonant converter.
- A control scheme for a multiple-output DC/DC current-source parallel resonant converter.
- A communication-less control scheme for a variable air-gap wireless energy transfer system using a current-source resonant converter.Esta tesis doctoral está centrada en los métodos de control aplicados a los convertidores resonantes con fuente de corriente, especialmente en dos aplicaciones distintas como son fuentes de alimentación conmutadas y sistemas de transferencia de energÃa sin hilos. De hecho, las aplicaciones existentes trabajan principalmente con convertidores alimentados mediante fuentes de tensión. Para los convertidores resonantes con fuente de tensión, se han analizado muchas estrategias de control en la literatura, lo que hace hoy en dÃa que esta sea una tecnologÃa madura. El convertidor resonante con fuente de corriente es una solución alternativa, que ofrece ventajas conocidas como corriente de entrada no pulsante, baja tensión para interruptores, circuitos de conducción sencillos y capacidades de protección contra cortocircuitos. Sin embargo, existe una falta evidente de métodos de control aplicables a los convertidores resonantes con fuente de corriente. Además, otro desafÃo en este tema es la obtención de modelos dinámicos apropiados para el diseño del control. Por lo tanto, los objetivos de esta tesis se utilizan para llenar estos vacÃos. Los esquemas de control propuestos son: - Esquema de control en frecuencia aplicado a un convertidor resonante paralelo con fuente de corriente para reguladores de tensión en continua - Esquema de control en modo de deslizamiento con modulación de amplitud aplicado a un convertidor resonante paralelo con fuente de corriente para reguladores de tensión en continua. - Esquema de control para un convertidor resonante paralelo con fuente de corriente para la regulación de tensión en continua de varias salidas. - Esquema de control sin comunicaciones para un sistema de transferencia de energÃa sin hilos con un transformador con entrehierro variable basado en un convertidor resonante con fuente de corriente.Postprint (published version
Perancangan Dan Implementasi Konverter Resonan AC-AC Dengan ZCS (Zero Current Switching) Untuk Aplikasi Pemanasan Induksi
Teknologi pemanasan induksi membutuhkan fitur-fitur khusus
seperti output daya yang tinggi, temperatur pemanasan yang sesuai
kebutuhan, variasi beban yang besar, dan biaya pembuatan yang minim.
Untuk memenuhi kebutuhan-kebutuhan tersebut rangkaian pemanasan
induksi klasik yang bekerja berdasarkan rectifier dan dc-link inverter
sudah cukup baik dalam memenuhi fitur-fitur diatas. Akan tetapi masih
terdapat kekurangan yaitu pada masalah efisiensi dan biaya
pengembangan. Oleh karenanya pada tugas akhir kali ini akan didesain
dan diimplementasikan Direct AC-AC Resonant Converter dengan ZCS
(Zero Current Switching) untuk mengurangi komponen yang digunakan,
menekan biaya, menambah keandalan, dan meningkatkan efisiensi.
Konverter ini merupakan voltage source series-resonant converter,
direncanakan memiliki daya output yang linier dengan frekuensinya dan
memiliki kontrol frekuensi yang tidak terlalu kompleks. Lebih jauh lagi
konverter ini akan mencapai soft switching selama transisi dari turn-on
dan turn-off dan memiliki daya output hingga sekitar 110 W.
Rencananya konverter ini akan digunakan untuk salah satu aplikasi
pemanasan induksi yaitu kompor listrik. Hal ini dapat dilakukan dengan
mengatur frekuensi agar dapat menghasilkan output daya yang
diinginkan. Untuk mengatur frekuensi switching pada switch di
konverter rencananya akan digunakan PWM yang dibangkitkan dengan
mikrokontroler dan dikuatkan dengan gate driver. Untuk Inputnya akan
digunakan tegangan dari catu daya AC hingga sebesar 100 V, 50 Hz.
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Induction heating technology require a special features such as
high power output, the heating temperature according to the needs, a
large load variations, and minimal manufacturing costs. To occupy
these needs, classical induction heating circuit works based rectifier
and inverter dc-link is good enough to occupy the above features.
However, there are still shortcomings, especially the issue of efficiency
and development costs. Therefore in this final project, will be designed
and implemented Direct AC-AC Converter with ZCS (Zero Current
Switching) to reduce the components used, reduce costs, increase
reliability, and improve efficiency. This converter is a voltage source
series-resonant converter, and planned has a linear output power with
frequency and has a frequency control that is not too complex.
Furthermore this converter will achieve soft switching during the
transition from turn-on and turn-off and has a power output of up to 110
W. The converters is planned to be used for one application of induction
heating, specifically electric stove. This can be done by adjusting the
frequency in order to produce the desired power output. To set the
switching frequency of the switches in this converter will be used PWM
generated by a microcontroller and strengthened by gate driver. The
input will be used voltages up to 100 V from AC power supply, and with
50 Hz frequency
Assessment of novel power electronic converters for drives applications
Phd ThesisIn the last twenty years, industrial and academic research has produced over one hundred new
converter topologies for drives applications. Regrettably, most of the published work has been
directed towards a single topology, giving an overall impression of a large number of
unconnected, competing techniques. To provide insight into this wide ranging subject area, an
overview of converter topologies is presented. Each topology is classified according to its
mode of operation and a family tree is derived encompassing all converter types. Selected
converters in each class are analysed, simulated and key operational characteristics identified.
Issues associated with the practical implementation of analysed topologies are discussed in
detail.
Of all AC-AC conversion techniques, it is concluded that softswitching converter topologies
offer the most attractive alternative to the standard hard switched converter in the power range
up to 100kW because of their high performance to cost ratio. Of the softswitching converters,
resonant dc-link topologies are shown to produce the poorest output performance although
they offer the cheapest solution. Auxiliary pole commutated inverters, on the other hand, can
achieve levels of performance approaching those of the hard switched topology while retaining
the benefits of softswitching. It is concluded that the auxiliary commutated resonant pole
inverter (ACPI) topology offers the greatest potential for exploitation in spite of its relatively
high capital cost.
Experimental results are presented for a 20kW hard switched inverter and an equivalent 20kW
ACPI. In each case the converter controller is implanted using a digital signal processor. For
the ACPI, a new control scheme, which eliminates the need for switch current and voltage
sensors, is implemented. Results show that the ACPI produces lower overall losses when
compared to its hardswitching counterpart. In addition, device voltage stress, output dv/dt and
levels of high frequency output harmonics are all reduced. Finally, it is concluded that
modularisation of the active devices, optimisation of semiconductor design and a reduction in
the number of additional sensors through the use of novel control methods, such as those
presented, will all play a part in the realisation of an economically viable system.Research Committee of the University of
Newcastle upon Tyn
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