Academic literature on the topic 'Class-E inverter'

This paper presents a comparative analysis of the class E and selected enhanced class E inverters, namely, the second and third harmonic group of class EFn, E/Fn and the class E Flat Top inverter. The inverters are designed under identical specifications and evaluated against the variation of switching frequency (f), duty ratio (D), capacitance ratio (k), and the load resistance (RL). To offer a comparative understanding, the performance parameters, namely, the power output capability, efficiency, peak switch voltage and current, peak resonant capacitor voltages, and the peak current in the lumped network, are determined quantitatively. It is found that the class EF2 and E/F3 inverters, in general, have higher efficiency and comparable power output capability with respect to the class E inverter. More specifically, the class EF2 (parallel LC and in series to the load network) and E/F3 (parallel LC and in series to the load network) maintain 90% efficiency compared to 80% for class E inverter at the optimum operating condition. Furthermore, the peak switch voltage and current in these inverters are on average 20–30% lower than the class E and other versions for k > 1. The analysis also shows that the class EF2 and E/F3 inverters should be operated in the stretch of 1 < k < 5 and D = 0.3–0.6 at the optimum load to sustain the high-performance standard.

A robust circuit design using matching technology to design the ultrasonic welding transducer driver with zero voltage switching is proposed. The feedback output voltage is used to control the oscillator frequency to achieve the self-tracking function. Experimental results exhibit that the Class-E inverter circuit can be effectively and stably applied on the high power ultrasonic welding system.

A new resonant dc/dc converter is proposed. It consists of a Class DE inverter and a Class E rectifier. Class E switching conditions are achieved for both the inverter and rectifier. Therefore, the efficiency of the converter is very high at switching frequencies in the megahertz range. In this paper, we give an analysis, design equations and experimental results for the proposed circuit. Experimental waveforms were in good agreement with the theory. The measured dc/dc power conversion efficiency was over 83% at 1 MHz 2.3 W.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, February, 2020
Cataloged from student-submitted PDF of thesis.
Includes bibliographical references (pages 91-95).
In Autonomous Underwater Vehicles (AUVs), many potential failure modes exist due to pressure housing and the need for connections between different pressure housings. Waterproof connectors do exist but drive up the price and weight of underwater systems, a costly disadvantage as mass and volume are at a premium for an underwater system. If we can remove the necessity for physical connectors, we can design cheaper, more robust submarines. This can be done with wireless power transfer (WPT), which can transmit power efficiently across mediums within the submarine, therefore eliminating the need for physical connections and making underwater systems more compact and light-weight. The thesis presents two WPT systems for an AUV with two different inverters that convert DC power to AC power that drive the WPT system. The first system presented uses a Class E Inverter, a common topology for DC-AC conversion, and the second system utilizes a Phi-2 Inverter, a topology that uses the inherent parasitic capacitances to substitute for physical components. The WPT system utilizes magnetic resonance coupling to transmit power from transmitter coils attached to the inverters to receiver coils attached to a load through a rectifier. Simulations show that, when correctly tuned, the two designs can give comparable performance in power transfer efficiency and range. The choice of design is likely to be decided by a combination of the size and weight of the finished system, along with the ease of design.
by Carla Nicole Pinzón.
M. Eng.
M.Eng. Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science

The Class-E topology was presented as a single-switch power amplifier with high efficiency at the optimum condition, where the switch enjoys zero-voltage switching (ZVS) and zero-voltage-derivative switching (ZDS). It is also used in MHz dc-dc converters, and in inverters for wireless power transfer, induction heating, and plasma pulsing. The load current in these applications usually varies over a range. Efficiency of a conventional Class-E design degrades dramatically due to the hard switching beyond the optimum conditions. Keeping ZVS with load change in a Class-E topology is preferred within the load range. Soft switching with load variation is realized by duty cycle modulation with additional transformer, matching network, or resistance compression network. Since two ZVS requirements need to be satisfied in a conventional Class-E design, at least two parameters are tuned under load variation. Thus, changing switching frequency, duty cycle, and component values were used. Impressively, a load-independent Class-E inverter design was presented in 1990 for maintaining ZVS and output voltage under a given load change without tuning any parameters, and it was validated with experimental results recently. The operating principle of this special design (inconsistent with the conventional design) is not elucidated in the published literatures. Load-independency illucidation by a Thevenin Model – A Thevenin model is then established (although Class-E is a nonliear circuit) to explain the load-independency with fixed switching frequency and duty cycle. The input block of a Class-E inverter (Vin, Lin, Cin, and S) behaves as a fixed voltage source vth1 and a fixed capacitive impedance Xth1 in series at switching frequency. When the output block (Lo and Co) is designed to compensate Xth1, the output current phase is always equal to the phase of vth1 with resistive load (satisfies the ZVS requirement of a load-independent design). Thus, soft switching is maintained within load variation. Output voltage is equal to vth1 since Xth1 is canceled, so that the output voltage is constant regardless of output resistance. Load-independency is achieved without adding any components or tuning any parameters. Sequential design and tuning of a load-independent ZVS Class-E inverter with constant voltage based on Thevenin Model - Based on the model, it's found that each circuit parameter is linked to only one of the targeted performance (ZVS, fixed voltage gain, and load range). Thus, the sequential design equations and steps are derived and presented. In each step, the desired performance (e.g. ZVS) now could be used to check and tune component values so that ZVS and fixed voltage gain in the desired load range is guaranteed in the final Class-E inverter, even when component values vary from the expectations. The Thevenin model and the load-independent design is then extended to any duty cycles. A prototype switched at 6.78 MHz with 10-V input, 11.3-V output, and 22.5-W maximum output power was fabricated and tested to validate the theory. Soft switching is maintained with 3% output voltage variation while the output power is reduced tenfold. A load-independent ZVS Class-E inverter with constant current by combining constant voltage design and a trans-susceptance network - A load-independent ZVS Class-E inverter with constant current under load variation is then presented, by combining the presented design (generating a constant voltage) and a trans-susceptance network (transferring the voltage to current). The impact of different types and the positions of the networks are discussed, and LCL network is selected so that both constant current and soft switching are maintained within the load variation. The operation principle, design, and tuning procedures are illustrated. The trade-off between input current ripple, output current amplitude, and the working load range is discussed. The expectations were validated by a design switched at 6.78 MHz with 10-V input, 1.4-A output, and 12.6-W maximum output power. Soft switching is maintained with 16% output current varying over a 10:1 output power range. A "ZVS" Class-E dc-dc converter by adding a diode rectifier bridge and compensate the induced varying capacitance at full-load condition - The load-independent Class-E design is extended to dc-dc converter by adding a diode rectifier bridge followed by the Class-E inverter. The equivalent impedance seen by the inverter consists of a varying capacitance and a varying resistance when the output changes. As illustrated before, ZVS and constant output can only be maintained with resistive load. Since the varying capacitance cannot be compensated for the whole load range, performance with using different compensation is discussed. With the selected full-load compensation, ZVS is achieved at full load condition and slight non-ZVS occurs for the other load conditions. The expectation was validated by a dc-dc converter switched at 6.78 MHz with 11 V input, 12 V output, and 22 W maximum output power. ZVS (including slight non-ZVS) is maintained with 16% output voltage variation over 20:1 output power range. Design of variable Capacitor by connecting two voltage-sensitive capacitors in series and controlling the bias voltage of them - The equivalent varying capacitance in the Class-E dc-dc converter can be compensated in the whole load range only with variable component. The sensitivity of a Class-E power conversion can also be improved by using variable capacitors. Thus, a Voltage Controlled Capacitor (VCC) is presented, based on the intrinsic property of Class II dielectric materials that permittivity changing much with electric field. Its equivalent circuit consists of two identical Class II capacitors in series. By changing the voltage of the common point of the two capacitors (named as control voltage), the two capacitance and the total capacitance are both changed. Its operation principle, measured characteristic, and the SPICE model are illustrated. The capacitance changes from 1 μF to 0.2 μF with a control voltage from 0 V to 25 V, resulting a 440% capacitance range. Since the voltage across the two capacitors (named as output voltage) also affects one of the capacitance when control voltage is applied, the capacitance range drops to only 40% with higher bias in the output voltage. Thus, a Linear Variable Capacitor (LVC) is presented. The equivalent circuit is the same as VCC, while one of the capacitance is designed much higher to mitigate the effect of output voltage. The structure, operational principle, required specifications, design procedures, and component selection were validated by a design example, with 380% maximum capacitance range and less than 20% drop in the designed capacitor voltage range. This work contributes to • Analytical analysis and Thevenin Model in load-independent Class-E power conversion • Variable capacitance with wide range
Doctor of Philosophy
The Class-E topology was presented as a single-switch power amplifier with high efficiency at the optimum condition. Efficiency of a conventional Class-E design degrades with load variation dramatically due to the hard switching beyond the optimum conditions. Since two requirements need to be satisfied for soft switching in a conventional Class-E design, at least two parameters are tuned under load variation. Impressively, a load-independent Class-E inverter design was presented for maintaining Zero-Voltage-Switching (ZVS) and output voltage under a given load change without tuning any parameters, and it was validated with experimental results recently. A Thevenin model is established in this work to explain the realization of load-independency with fixed switching frequency and duty cycle. Based on that, a sequential design and tuning process is presented. A prototype switched at 6.78 MHz with 10-V input, 11.3-V output, and 22.5-W maximum output power was fabricated and tested to validate the theory. Soft switching is maintained with 3% output voltage variation while the output power is reduced tenfold. A load-independent ZVS Class-E inverter with constant current under load variation is then presented, by combining the presented design and a trans-susceptance network. The expectations were validated by a design switched at 6.78 MHz with 10-V input, 1.4-A output, and 12.6-W maximum output power. Soft switching is maintained with 16% output current varying over a 10:1 output power range. The load-independent Class-E design is extended to dc-dc converter by adding a diode rectifier bridge, inducing a varying capacitance. With the selected full-load compensation, ZVS is achieved at full load condition and slight non-ZVS occurs for the other load conditions. The expectation was validated by a dc-dc converter switched at 6.78 MHz with 11 V input, 12 V output, and 22 W maximum output power. ZVS (including slight non-ZVS) is maintained with 16% output voltage variation over 20:1 output power range. The varying capacitance in the Class-E dc-dc converter needs variable component to compensate. Thus, a Voltage Controlled Capacitor (VCC) is presented. The capacitance changes from 1 μF to 0.2 μF with a control voltage from 0 V to 25 V, resulting a 440% capacitance range. The capacitance range drops to only 40% with higher bias in the output voltage. Thus, a Linear Variable Capacitor (LVC) is presented, with 380% maximum capacitance range and less than 20% drop in the designed capacitor voltage range.

Neste projeto, propomos estudar a chamada \"Teoria de Corpos de Classe,\" que oferece uma descrição simples das extensões abelianas de corpos locais e globais, bem como algumas de suas aplicações, como os teoremas de Kronecker-Weber e Scholz-Reichardt
In this work, we study the so called \"Class Field Theory\", which give us a simple description of the abelian extension of local and global elds. We also study some applications, like the Kronecker-Weber and Scholz-Reichardt theorems

碩士
明新科技大學
電機工程研究所
99
In this thesis, the zero voltage switching, output power, efficiency and harmonic distortion (THD) of Class E inverter are analyzed while the resonant components, i.e. R, L, and C, operating frequency, and duty cycle are varying. Also, in this research, the parallel driving of class E inverter is studied. The behaviors of harmonic varying, power output and power converting efficiency versus the changing of control phase between the two parallel driving inverters. Moreover, in this thesis, an auto tuning control method is proposed to hold on optimum ZVS operation for class E inverter while any resonant component is shifting. By Matalb/Psim and Pspice simulating, the waveforms of circuit response and control performance can be checked to verify the proposed method. In addition, the FPGA based controller is implemented to achieve the auto tuning control of class E inverter.

碩士
國立成功大學
電機工程學系碩博士班
101
In this thesis, a low-pressure radio-frequency plasma power supply is analyzed and implemented. The plasma power system consists of three stages, including the first stage of a boost power factor correction (PFC) circuit, the second stage of asymmetrical half-bridge(ASHB) DC-DC converter, and the third stage is Class-E inverter. The PFC circuit achieves high power factor and provides DC bus voltage for the secondary stage. The asymmetrical half-bridge converter in the second stage converts the bus voltage into controllable DC voltage. By adjusting the DC output voltage of the asymmetrical half-bridge converter, the plasma power can be controlled. Class-E inverter converts DC voltage into 13.56 MHz AC radio frequency power to the load. The design of the wide output voltage range asymmetrical half-bridge converter is presented, and the ZVS Class-E inverter is analyzed. The phase angle between the resonant current and the input voltage of resonant tank is analyzed, so lower current stress is realized to reduce the conduction loss from power switch and device. The hardware prototype is first tested with a plasma equivalent load in a output power range of 30 W~300 W, then the system is applied to a reactive ion etcher (RIE) plasma chamber to verify that system is feasible for low pressure plasma reactors.

碩士
國立臺南大學
通訊工程研究所碩士班
98
Aimed at the design of AC LED drive circuit, this thesis has proposed a class-E inverter and pulse width modulation as the main structure in which an L-C resonant circuit is included for voltage filtering and soft-switching. With the proposed circuit, the circuit operation efficiency can be improved, while the power density can be also upgraded through the employment of high-frequency features of circuit devices. To validate the feasibility, mathematical derivations were made with theoretical simulations and experimental validations. Test results are beneficial as the reference for high-frequency LED drive applications.

碩士
國立中山大學
電機工程學系研究所
90
A single-stage high-power-factor electronic ballast with class E inverter is proposed for driving the fluorescent lamp. The circuit configuration is obtained from the integration of a buck-boost converter for power-factor- correction (PFC) and a class E resonant inverter for ballasting. The integrated ballast circuit requires only one active power switch and simple control. Operating the buck-boost converter in discontinuous conduction mode (DCM) at a fixed frequency, the electronic ballast can achieve nearly unity power factor. With pulse-width-modulation (PWM), the electronic ballast can provide an appropriate filament current for preheating, a high voltage for ignition, and then a desired lamp current for steady-state operation. An additional control circuit is included to eliminate the glow current during preheating stage. The operation of the ballast-lamp circuit is analyzed by fundamental approximation. Computer simulations are made and design equations are derived on basis of the power-dependent resistance model of the fluorescent lamp. With carefully designed circuit parameters, the active power switch can be switched on at zero current to reduce the switching losses leading to a higher efficiency. An experimental circuit designed for a PL-27W compact fluorescent lamp is built and tested to verify the computer simulations and analytical predictions. Experimental results show that satisfactory performances can be obtained on the proposed electronic ballast.

碩士
國立成功大學
電機工程學系
104
In this thesis, a 3 kW RF plasma power supply is analyzed and implemented. This plasma power supply can be separated into three parts. The first part is a power factor correction circuit. The purpose of this circuit is to enhance the quality of the utility which is the input source. The structure of this power factor correction circuit is an interleave boost converter. The second part is a full-bridge phase shift DC/DC converter, this circuit can control the input power sent to the RF inverter by tunning the input voltage from a wide range of 0~300V. The third part is a Class-E inverter, this circuit transfers the DC input voltage into the AC output voltage. In the beginning, this paper analyzes the working modes of the power factor correction circuit and chooses the suitable structure. Then the full-bridge phase shift DC/DC converter which can control the DC output voltage by adjusting the phase-angle is discussed. Finally, the switch pressure in the Class-E inverter and phase-angle of the output current is examined. Switching losses caused by high frequency switching is successfully reduced.

碩士
明新科技大學
電機工程研究所
95
Wireless energy delivery has always been one of our greatest dreams. In contrast with the high power delivery is difficult to realize, the low power delivery for short distance circuit system is feasible despite the low efficiency of power delivery. In the situations of being not able to provide electricity, the method of wireless energy delivery can solve the problem of power supply and it is also the main purpose of RF powering. In this thesis, we will apply Class E inverter to driving the RF powering system to improve the conversion efficiency for this wireless energy delivery system. The Class E inverter is working on L-C resonant situation to achieve the zero voltage switching (ZVS) condition. To operate the circuit on resonant situation, the switching control has to be very precise, since any parameter’s variation in the circuit is high sensitivity. There will be a thoroughly discussion of when the parameter had changed, how the ZVS would have performed; in hoping to obtain a strategy of how to operate the ZVS. All the parameter’s variations will be discussed in the simulation of MatLab/Simulink and PSpice; and would realize the circuit to demonstrate the accuracy of the calculations. Beside the above, there will also be a RF powering system’s realization using Class E inverter to demonstrate the practicability. Moreover, we will integrate the RF powering system and CPLD as a micro controller to implement a non-contact sensing system

A educação atual apresenta-se na terceira onda tecnológica denominada de Mobile Learning (m-learning), caracterizada pelo uso de equipamentos portáteis, pela mobilidade global do usuário, conectividade ubíqua, independência de dispositivo e ambiente computacional disponível em qualquer lugar e a qualquer tempo. Na presente tese é proposto o ML-SAI, um modelo pedagógico para atividades de mobile learning, que visa contribuir na orientação, planejamento e realização de atividades pedagógicas, por meio de dispositivos móveis, tendo como base a abordagem da Sala de Aula Invertida (SAI). Nesta abordagem, o conteúdo é estudado em casa com o auxílio da tecnologia e na escola os alunos tiram as suas dúvidas e compartilham o seu aprendizado com o auxílio do professor, orientando e realizando feedbacks, com a utilização de atividades, tais como: projetos, experimentos, debates, atividades em grupo, pesquisas, entre outros. Assim o modelo apresenta como diferencial o fato de integrar o aprendizado on-line com o presencial, relacionando duas abordagens de ensino atuais, o m-learning e a SAI. Para a elaboração do ML-SAI, além da revisão bibliográfica, foram realizadas pesquisas exploratórias por meio de um levantamento de indicativos e três estudos de casos pilotos, que forneceram subsídios importantes que permitiram compreender melhor algumas das questões relacionadas ao uso educacional de tecnologias móveis combinadas com a abordagem SAI. Para a experimentação do modelo foram organizados três estudos de casos envolvendo alunos do ensino Médio e Superior, que ocorreram durante o ano letivo de 2019, com a utilização dos celulares dos próprios alunos. A coleta e análise dos dados foi promovida por meio de questionários on-line do Google Forms, envolvendo abordagem qualitativa e quantitativa, devido às características dos dados. Por fim, as experimentações realizadas, sinalizaram que o ML-SAI apresenta potencial para orientar as atividades de m-learning, colaborando positivamente com o seu desenvolvimento.
Today's education is in the third technological wave called Mobile Learning (m-learning), characterized by the use of portable equipment, global user mobility, ubiquitous connectivity, device independence and computing environment available anywhere and anytime. This thesis proposes the ML-SAI, a pedagogical model for mobile learning activities, which aims to contribute to the orientation, planning and implementation of educational activities through mobile devices, based on the approach of the Inverted Classroom (SAI). In this approach, the content is studied at home with the help of technology and at school students place their questions and share their learning with the help of the teacher, guiding and performing feedbacks, using activities such as: projects, experiments, debates, group activities, research, among others. Thus, the model presents as a differential the fact that it integrates online learning with classroom learning, relating two current teaching approaches, m-learning and SAI. For the elaboration of the ML-SAI, in addition to the literature review, exploratory research was conducted through a survey of indicatives and three pilot case studies, which provided important insights that allowed us to better understand some of the issues related to the educational use of combined mobile technologies. with the SAI theory. In order to test the model, three case studies were organized involving high school and college students, which took place during the 2019 school year, using the students' own cell phones. Data collection and analysis was promoted through Google Forms online questionnaires, involving a qualitative and quantitative approach, due to the characteristics of the data. Finally, the experiments carried out indicated that ML-SAI has the potential to guide m-learning activities, contributing positively to their development.
L'éducation se situe aujourd'hui dans la troisième vague technologique appelée Mobile Learning (m-learning), caractérisée par l'utilisation d'équipements portables, la mobilité globale des utilisateurs, la connectivité omniprésente, l'indépendance des périphériques et l'environnement informatique disponibles partout et à tout moment. Cette thèse propose ML-SAI, un modèle pédagogique pour les activités d’apprentissage mobile, qui vise à contribuer à l’orientation, à la planification et à la mise en oeuvre d’activités éducatives par le biais d’appareils mobiles, sur la base de la approche de la classe inversée (SAI). Dans cette approche, le contenu est étudié à la maison à l’aide de la technologie et à l’école, les élèves posent leurs questions et partagent leur apprentissage avec l’aide de l’enseignant, en guidant et en effectuant des réactions en utilisant des activités telles que: projets, expériences, etc. débats, activités de groupe, recherches, entre autres. Ainsi, le modèle se distingue par le fait qu’il intègre l’apprentissage en ligne à l’apprentissage en classe et met en relation deux approches pédagogiques actuelles, le m-learning et le SAI. Pour l’élaboration de ML-SAI, outre la revue de la littérature, des recherches exploratoires ont été menées au moyen d’une enquête sur les indicateurs et de trois études de cas pilotes, qui ont permis de mieux comprendre certaines des questions liées à l’utilisation éducative des technologies mobiles combinées avec la théorie des SAI. Afin d'expérimenter le modèle, trois études de cas portant sur des lycéens et des étudiants ont été organisées au cours de l'année scolaire 2019, à l'aide de leur propre téléphone cellulaire. La collecte et l'analyse des données ont été favorisées par le biais de questionnaires en ligne de Google Forms, impliquant une approche qualitative et quantitative, en raison des caractéristiques des données. Enfin, les expériences menées ont montré que ML-SAI a le potentiel de guider les activités d’apprentissage mobile, contribuant de manière positive ao leur développement.