Search

In this paper, a modular resonant inverter is proposed for high frequency industrial heating applications. To maintain a uniform heating profile, the inverter is operated in constant power mode. A hybrid voltage and frequency control is proposed. Voltage control is used for active power tracking while frequency control is used to minimise circulating current due to reactive power and to achieve soft switching for the inverter switches. Analytical and test results are shown to verify the proposed approach. [ABSTRACT FROM AUTHOR]

This article deals with the design, development, and analysis of a wireless power transfer system prototype based on capacitive coupling. The system is intended for the continuous charging of a suspended mine drivetrain. It consists of a resonant inverter, primary and secondary matching circuits, a suitable capacitive coupler, and a rectifier with a load, ultimately serving as a battery charger for a mobile energy storage device. The system successfully achieved the target output voltage of 320 V and a charger output power of 2 kW at an operating frequency of 300 kHz. Additionally, the total system efficiency was at the level of 60%, ensuring that the RMS voltages on passive components remained below 3 kV. [ABSTRACT FROM AUTHOR]

This paper presents an optimization-based approach for the design of energy-dosing resonant inverters (RI) using a reference curve. RI are widely used in areas such as wireless charging, induction heating, and high-frequency power supplies due to their high efficiency and soft-switching capability. The proposed methodology uses a reference current curve in the alternating current (AC) circuit that describes the ideal behavior of the inverter during the start-up transient in order to operate in energy metering mode and minimize switching losses. This approach analyzes and optimizes the values of the circuit elements whose initial values are determined by applying a rational design methodology. The results of the study demonstrate increased dynamics of the power circuit and better stability compared to applying traditional design methods. The presented simulation results confirm the effectiveness of the proposed optimization and the improvement of the characteristics of the studied device. [ABSTRACT FROM AUTHOR]

In inductively coupled power transfer (ICPT) systems, the mutual inductance and load are the key parameters to realize high performance control, which is difficult to measure directly in rail transit. Thus, a method realizing mutual inductance and load identification using only the output voltage and current of a high-frequency inverter is proposed in this paper. Dual-frequency modulation, where one is the resonant frequency and the other is the non-resonant frequency, is used in the high-frequency inverter. Then the amplitudes and phases of the output voltage and current of the high-frequency inverter at the resonant frequency and the non-resonant frequency can be obtained based on the fast Fourier transform (FFT) method. The circuit is decomposed according to different frequencies. Then a mathematical model of the ICPT system is established. Therefore, the mutual inductance and load can be identified. Finally, the effectiveness of the proposed method is verified based on an ICPT prototype. Experimental results show that the identification errors of mutual inductance and load are less than 5%. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Polytechnic is the property of Journal of Polytechnic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Summary: The paper designs an efficient three‐phase soft‐switching inverter with asymmetric auxiliary circuits, which is beneficial for further miniaturization and efficiency optimization. Only two auxiliary switches, one resonant inductor, and three resonant capacitors make up simple asymmetric auxiliary circuits of each phase, contributing to the reduction of power loss and hardware cost. As soon as the simple auxiliary circuits get involved in the operation of the designed inverter, main switches can realize zero‐voltage switching within the entire load range. The reduction of power loss of auxiliary circuits and main switches is conducive to further efficiency optimization. The paper expounds every operating status during one switching period. The relevant experimental waveforms make known that switching devices can realize soft‐switching. The efficiency reaches 99% at rated operation status of the designed inverter, confirming that the designed inverter has superiority over comparison objects in the experiment with regard to the efficiency. Thus, the structural simplification of auxiliary circuits is an effective method for further miniaturization and efficiency optimization. [ABSTRACT FROM AUTHOR]

This work consists of the analysis and design of a LC series resonant inverter with reactive element control for induction heating hardening applications. This novel method uses a current-controlled variable transformer (VT) to control the reflected inductance of the inductor in the resonant, and a magnetic energy recovery switch (MERS) to vary the influence of the capacitor as a reactive power compensation element. This converter topology allows quality factor (Q) or operating frequency (f s w) to be adjusted, making it possible to harden workpieces of different geometries and materials with a single converter. In the article, the design of both elements will be studied and tested. Experimental results were carried out with a 10 kW induction heating inverter prototype, with a frequency range of 60 kHz to 100 kHz and a quality factor of 6 to 10, measuring efficiencies above 95%. [ABSTRACT FROM AUTHOR]

This paper investigates the application of fractional proportional–resonant controllers within the voltage control loop of grid-forming inverters. The use of such controllers introduces an additional degree of freedom, enabling greater flexibility in manipulating frequency trajectories. This flexibility can be harnessed to improve tracking error and enhance disturbance rejection, particularly in applications requiring precise voltage regulation. The paper conducts a conceptual stability analysis of ideal fractional proportional–resonant controllers using the Nyquist criterion. A tuning procedure based on robustness criteria for the proposed controller is also addressed. This tuning strategy is used to compare different controllers under the same conditions. In addition, a sensitivity analysis is provided, comparing the performance of fractional proportional–resonant controllers with traditional proportional–resonant controllers equipped with harmonic compensation. The controller's formulation and performance are validated through simulations and tested with a 20 kVA inverter under high non-linear loads. Compared to classical control approaches, the fractional tuning parameter enhances tracking performance, reduces phase delay, and improves disturbance rejection. These improvements are achieved with a controller designed to minimise computational demands in terms of memory usage and execution time. [ABSTRACT FROM AUTHOR]

Phase-locked loop systems (PLL) are widely used in control circuits of transistor resonant voltage inverters of induction heating installations. One of disadvantages of PLL systems is low speed, which is caused by the presence of a lowpass filter. This disadvantage is absent in self-oscillating systems, when the switching moment of the transistors is determined on each of half periods. At the same time, an asymmetry of half periods is possible, which is a significant disadvantage if there is a transformer at the output of the inverter. A self-oscillating digital control system for a resonant voltage inverter and equal half periods durations of the inverter output voltage has been developed. It can work with different methods of regulating the output current and allows to provide switching modes of transistors with minimal power losses. [ABSTRACT FROM AUTHOR]

This paper presents the design and optimization of a small-size electromagnetic induction heating control system powered by a 3.7 V–900 mAh lithium battery and featuring an LC series resonant full-bridge inverter circuit, which can be used for small metal material heating applications, such as micro medical devices. The effects of the resonant capacitance, inductor wire diameter, heating tube material, and wall thickness were studied to maximize the heating rate of the workpiece and simultaneously reduce the temperature rise of the NMOS transistor. The optimal circuit configuration meeting the design requirements was finally identified by comparing the operational parameters and NMOS transistor loss under different circuit conditions. Validation experiments were conducted on designed electromagnetic induction smoking devices. The results indicate that under an output current of 4.6 A, the heating tube can reach the temperature target of 250 °C within 11 s, and all NMOS transistors stay below 50 °C in a 5 min heating process. [ABSTRACT FROM AUTHOR]

This article presents an analysis of a converter based on an LC resonant inverter for induction heating applications. It employs a current-controlled variable transformer (VT) in conjunction with phase shift regulation (PS) to operate at a fixed frequency close to the resonance frequency. The converter maintains a small switching angle, enabling substantial load variations without sacrificing zero voltage switching (ZVS) for the transistors. This innovative method enhances the inverter's performance across the entire operating range. Additionally, a new design of the transformer structure with a variable ratio will be analyzed, enabling mathematical modeling. The obtained results demonstrate a performance exceeding 99%. Both the inverter and variable transformer designs were experimentally validated using a 15 kW, 200 kHz converter for induction heating applications with silicon carbide (SiC) MOSFETs. [ABSTRACT FROM AUTHOR]

In this paper, the capacitive power transfer (CPT) technology is used as an alternative to inductive power transfer (IPT). CPT relies on electric fields that are not sensitive to the presence of any metals, utilizes metal electrodes for power transfer, and is less bulky compared to IPT. The proposed CPT system utilizes a Class-E resonant inverter with a double-sided inductorcapacitor (LC) matching circuit which operates at an optimum load, RL = 50 Ω with a duty cycle, D=0.5 to gain an output power, Po = 8.02 W and efficiency, η=84.6%. The proposed CPT system enhances the system’s efficiency as compared to the past research while preserving the zero-voltage switching (ZVS) condition within a wider load range from 50 Ω to 1,316 Ω. This paper also shows that the proposed CPT system is less sensitive to load and coupling variations. Finally, the rate of power dissipated at varied load resistances, dPo dRL has been derived successfully to determine the sensitivity level of the proposed CPT systems toward load variations. These equations are then validated by plotting the efficiency graphs based on load and coupling variations. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis of a novel control approach to improve the efficiency of parallel LLC resonant inverters using a combination of a current controlled variable inductor (VI) and phase shift (PS). The proposed control aims to reduce the Root Mean Square (RMS) current, thereby reducing conduction and switching losses, and improving power transfer efficiency, while considering zero-voltage-switching (ZVS) operation, output power variations and load changes. Furthermore, a design methodology for the variable inductor is proposed, and design considerations relevant to this application are discussed. The effectiveness of the proposed approach is evaluated through mathematical modeling and experimental results. The mathematical modeling results show that the proposed approach, utilizing SiC MOSFETs, maintains a maximum efficiency of 98.5% for a 20 kW inverter over a wider range of output power, which is a significant improvement over existing approaches. The experimental results also confirm the effectiveness of the proposed control in improving the efficiency of parallel LLC resonant inverters. [ABSTRACT FROM AUTHOR]

This paper presents new resonant inverter topologies for dual-frequency induction heating (IH). These 2T1C and 3T topologies combine the advantageous features of two- and one-inverter solutions. An analytical description of the load impedance of a dual-frequency series-parallel circuit has been made. Using manufacturer datasheets and LTspice models of selected transistors, a MATLAB model was parameterized. Based on it, power losses are determined as a function of the following parameters: nominal power, frequency and DC bus voltage. The obtained results allowed for determining the data necessary in the design process. The research has been experimentally verified. Tests were carried out for pulsing and simultaneous operation. Power control characteristics as a function of frequency are determined. The possibility of operating the inverter with high efficiency (>97%) in the proposed 2T1C and 3T systems at nominal power is demonstrated. [ABSTRACT FROM AUTHOR]

The resonance circuit's design has a major influence on the inductive electric vehicle (EV) charging system's performance and the distance between the primary and secondary inductive coils. If resonance circuitry is not included in an inductive power transfer (IPT) system, its performance suffers dramatically and its power transfer efficiency suffers significantly. Furthermore, the design of the resonance circuit has a major impact on the rating as well as the voltage and current strains on the semiconductor switches. The sequence, amplitude, and shape of the waveform are determined by the configuration of the energy storage components. The arrangement of these components is critical in defining how the inductive power transfer system behaves and operates. A few popular architectures play an important role in shaping how the system works. In this paper, the significance and effect of resonance circuits on the inductive charging of electric vehicles have been reviewed and discussed comprehensively. Furthermore, a detailed discussion was presented for the second-order resonance circuit, the higher-order resonance circuit, and the hybrid resonance circuit. Additionally, H-bridge resonant inverter topology was discussed and three main resonant architectures for the H-bridge inverter were studied inclusively. They include the inductor-capacitor-inductor (LCL) resonance architecture, switched inductor-capacitor (SLC) resonance architecture, and High-gain resonance architecture. Also, a comparison of these architectures was done and represented in tabular form. Lastly, an analysis of the effect of frequency variations in the resonant circuit architectures. [ABSTRACT FROM AUTHOR]

Domestic induction heaters provide efficient, fast, and safe heating. Variable circuit parameters in domestic induction heaters show different characteristics depending on the type of parts used for heating and the area they cover on the heating coil. For this reason, resonant frequency, maximum inverter current, and quality factor parameters of the induction heaters also change. In this study, the tests of the domestic induction heater circuit with series resonant inverter were carried out with various of workpieces diameters. The resonant frequency and maximum inverter current parameters obtained from the experimental studies, curve fitting process was performed in the MATLAB and a function on related with heater parameters was derived. By using the obtained functions, the resonant frequency and maximum inverter current of the materials in the workpieces with intermediate diameters were calculated with high accuracy and compared experimentally. Analytical calculations and experimental results confirmed each other with an accuracy and it was shown that induction heater circuit parameters could also be calculated by analytical solution method. [ABSTRACT FROM AUTHOR]

In order to improve the immunity and speed tracking performance of active inverters in resonant overvoltage flexible suppression under load variation, parameter perturbation, and other uncertainties, a current control strategy of a resonant overvoltage flexible grounding device based on a cascading linear-nonlinear active disturbance rejection controller is proposed in this paper. First, the mathematical model of the flexible device considering load disturbance and parameter mismatch is established. Second, a cascade of linear and nonlinear extended state observers is designed to estimate and compensate the uncertain disturbance of the system in real time. The former linear extended state observer ensures the stability of the system under large disturbance, and the latter nonlinear extended state observer further improves the estimation accuracy of the disturbance by using the nonlinear mechanism. Finally, the flexible grounding system based on PI control and cascaded linear-nonlinear active disturbance rejection control (CL-NLADRC) is simulated and compared. Compared with PI control, NLADRC, and CLADRC, the current drop of the proposed CL-NLADRC during loading is 0.03 kA, which is 81.1%, 85.7%, and 73% of the three, respectively, and the regulation time is 13 ms, which is 82%, 75%, and 18.7% shorter than the three, respectively. The speed increase during load shedding is 93.5%, 80.5%, and 74.3% of the three, and the adjustment time is shortened by 80%, 73%, and 28%, respectively. The superiority of the proposed method is verified. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The article presents the influence of the parameters of the high voltage direct current (HVDC) generator with a multiplier, such as: leakage inductance of the high voltage (HV) transformer, capacitance, and the number of multiplier stages on the value of the output voltage, voltage ripple, power and frequency of the supply voltage as a function of the output current. The presented characteristics were obtained under the synchronization conditions of the inverter output voltage and current that powers the multiplier. The presented results will be useful when designing HVDC generators with Cockcroft-Walton multipliers. [ABSTRACT FROM AUTHOR]

Summary: Single‐phase high‐frequency resonant inverters (SPHFRIs) with high power density, fast dynamic response, and high energy conversion efficiency have been widely studied and used in academia and industry. With the development of the modularization concept, the operation of multiple inverter modules is desirable because it can remove the limitations of cost, heat dissipation, and component volume in single inverter operation. However, a critical challenge in multiple inverter systems is that the both the phase and magnitude of the output voltage of each inverter module must be controllable to eliminate circulating currents between inverter modules. Great efforts have been made to solve this problem from three aspects: topology, modulation, and control strategy. In this paper, modulation strategies and topologies of different inverters are presented and reviewed to provide guidance to researchers working in this field. Firstly, multiple inverter system based on the SPHFRI is described and its advantages and disadvantages are analyzed. An important issue in the study of multiple inverter systems is presented, that is, the suppression of circulating current. Secondly, the circulating currents in a multiple inverter system are analyzed and derived from two aspects: (1) magnitude and phase angle and (2) active and reactive currents. Thirdly, the inverters used in the multiple inverter system are introduced, and their operating principles, advantages, and disadvantages are reviewed. A key comparison of several inverters is presented for the benefit of the readers. Fourth, through PI closed‐loop simulation, the performance of different multiple inverter systems for suppressing the circulating current is compared in two situations: (1) with magnitude discrepancy only and (2) with both magnitude and phase discrepancy. Finally, the advantages and disadvantages of each inverter are summarized, and the state of the art and future trends are presented. [ABSTRACT FROM AUTHOR]

Induction heating (IH) is the most preferred technology for domestic and industrial heating applications owing to its advantages over conventional heating methods. Heating requirements for ferromagnetic (FM) and non-ferromagnetic (N-FM) materials are different. There is an increase in research for heating these different material vessels. In this research work, a three switch dual frequency resonant inverter (3 S-DFRI) with dual frequency control is proposed. It has been used for simultaneous and independent heating of steel and aluminum loads. The inverter operation is verified by rigorous simulation and experimentation on the developed 2 kW prototype. It can also be extended for multiple loads by additional inverter legs each with three switches. Each additional leg provides two independent load operation. Compatibility with different material IH loads, reduced number of switching devices, no use of electro-mechanical switches, compact size and high efficiency are the key advantages of the proposed inverter. [ABSTRACT FROM AUTHOR]

The object of research is high-voltage systems of electric discharge installations for various technological purposes. The work reports solving the problem of enabling the rate of charging of a capacitive energy storage, set by the requirements of a certain high-voltage technology. The quantitative characteristics of the deviation of the output current of the resonant inverter from the set stabilized value when changing the switching frequency of inverter switches in the range of output voltage change from 0 to 20 kV were determined. Using the Fourier transform of the rectangular input voltage, the frequency regulation possibility of the output current of the charger for capacitive energy storage devices was analyzed. Estimation dependences of the output current of resonant inverter on the load resistance and frequency deviation from resonant frequency were derived. These dependences could be used to implement frequency control over the switching inverter transistors, with the help of which the given effective value of the output current of the resonant inverter is obtained. A method of frequency regulation of the output current in high-voltage transformerless resonant charging devices of capacitive energy storage devices has been developed. Special feature of this method is that it is based on the frequency dependence of reactive resistances of the inductance and capacitance of the resonant circuit connected in series. Owing to that, it makes it possible to adjust the switching frequency of the inverter’s power switches depending on the relative resistance of the load and the specified growth rate of the capacitive energy storage voltage. The results reported here could be used in the design of benches for testing the electrical strength of high-voltage cables, as well as for the construction of high-voltage transformerless chargers in systems of electric discharge impulse processing of materials. [ABSTRACT FROM AUTHOR]

Soft-switching technologies can effectively solve the problem of switching losses caused by increasing switching frequency of grid-connected inverters. As a branch of soft-switching technologies, load-side resonant soft-switching is a hotspot for applications of high-frequency inverters, because it has the advantage of achieving soft-switching without using additional components. However, the traditional PI control strategy based on the linear model is prone to destabilization and non-robust dynamic performance when large signal perturbation occurs. In this paper, a novel Passivity-Based Control (PBC) method is proposed to improve the dynamic performance of load-side resonant soft-switching grid-connected inverter. Besides, the model based on the Port Controlled Hamiltonian (PCH) model of the soft switching inverter is carried out, and the passivity-based controller is designed based on the established model using the way of interconnection and damping assignmentpassivity based control (IDA-PBC). Both stable performance and dynamic performance of the load-side resonant soft-switching inverter can be improved over the whole operating range. Finally, a 750 W load-side resonant soft-switching inverter simulation model is built and the output performance is compared with the traditional PI control strategy under stable and dynamic conditions. The simulation results show that the proposed control strategy reduces the harmonic distortion rate and improves the quality of the output waveforms. [ABSTRACT FROM AUTHOR]

The main steps of the synthesis of the control of DC-DC converters based on Matlab are discussed in the manuscript. Shown is the implementation and setup of 3 types of controllers used in a specific example Boost DC-DC converter: classic PID, neural network, and Fuzzy. For some of the cases, the source code is also given, thus the examples presented are useful both for the purposes of training in power electronics and for the specialists-designers of power electronic devices. [ABSTRACT FROM AUTHOR]

Abstract Induction heating offers numerous advantages over conventional methods for heating high-pressure fluids in hydraulic testing applications. It simplifies complex processes, mitigates the risks associated with high-pressure environments, and enhances overall safety. The design of an efficient induction heating system requires a clear understanding of its key components, including the resonant tank circuit, impedance matching and isolation stage, high-frequency inverter, driver circuitry, and controller. The configuration of the resonant circuit plays a crucial role in device ratings and control methods. To meet the demanding requirements of switching devices like IGBTs, the driver circuit must ensure high immunity to interferences and failure. Effective system design allows the heating circuit to operate close to resonant switching, minimizing switching losses and cooling requirements. This paper presents the design and development of a 4-kW induction heater specifically tailored for inline heating of aviation fuel under high pressure. The system aims to achieve a precise temperature profile for testing line-replaceable units (LRUs) used in aircraft. The design methodology encompasses the selection of the resonant tank circuit configuration, impedance matching and isolation stage, high-frequency inverter, driver circuitry, and control strategies. Through extensive simulations in LTspice and experimental measurements, power losses in different components of the power conversion circuits are assessed, and overall system efficiency is evaluated. The results demonstrate the proposed induction heating system’s remarkable energy efficiency, reduced switching losses, and improved reliability. Furthermore, a comprehensive comparison with existing designs and industry norms is presented, highlighting the distinct advantages of the proposed system in terms of cost-effectiveness, energy efficiency, material utilization, and processing time. This research contributes valuable insights into the design and optimization of induction heating systems for high-pressure fluid heating applications, providing a practical and efficient solution for the aviation industry.

This paper presents a modification of class D zero-voltage-switching (D-ZVS) resonant inverter for ultrasonic cleaning applications. The output power is controlled using the adjustable duty of a buck converter. Combined with a phase-locked loop control, the switching frequency of the inverter is automatically adjusted to maintain a lagging phase angle under load–parameter variations during the cleaning process. With the proposed modification, the inverter maintains ZVS throughout the power control range. Moreover, the snubber capacitor connection is used to reduce turn-off losses. The control algorithms are implemented using digital signal processing (TMS320F28335 for buck converter and TMS320F28379D for inverter). The proposed method for a 100-W piezoceramic ultrasonic transducer (PZT) is verified using computer simulation and laboratory experimental results and is found to be more efficient than other methods. The operating frequency and power ranges under investigation are 36.5–36.96 kHz and 15–95 W, respectively. [ABSTRACT FROM AUTHOR]

In this study a novel drive for the Switched Reluctance Motor (SRM), powered by the solar photo voltaic (SPV) source, using a Partial Resonant Inverter (PRI) followed by a Doubler Rectifier (DR) for water pumping applications, has been proposed and validated. The PRI DR combination offers a large voltage gain that is required while using low-voltage SPV sources. The PRI increases the voltage level by resonance and also it exhibits zero voltage switching so that the switching losses are reduced. The proposed system also offers a sliding mode controller based on Maximum PowerPoint Tracking implemented in the PRI. The proposed system is a fixed torque variable speed application where the speed follows the solar irradiance. The proposed idea has been validated using simulations and experimental prototypes. [ABSTRACT FROM AUTHOR]

This paper presents a method that improves the reliability of half-bridge (HB) series resonant inverters (SRI) for high-frequency induction heating applications. Many industrial processes, like induction heat treatments, are very repetitive. This cyclical operation represents a strong limitation of the inverter’s reliability, mainly due to the accelerated stress of the power semiconductors. This method consists in an enhanced asymmetrical pulse width modulation (EAPWM) that allows distributing the losses across the components, thereby reducing the cyclic increase in junction temperature of the power devices, and thus achieves a reliability that is more than twice as high as that achieved using traditional modulation methods. The work methodology includes a theoretical study of the HB inverter and a complete analysis of losses. The presented design rules have been used to implement a 25 kW, 100 kHz inverter. The use of silicon carbide (SiC) MOSFET transistors allows reaching an efficiency greater than 99%. The analytical results obtained have been experimentally validated by testing the inverter on an induction heating test bench. [ABSTRACT FROM AUTHOR]

Regulating the load voltage is of major importance for ensuring high transmission efficiency in wireless power transfer (WPT) systems. In this context, this work presents a novel control strategy applied in the dc-ac converter used in the primary side of a WPT system. The performance of a class-DE resonant inverter is investigated considering that such topology presents inherent soft-switching characteristics, thus implying reduced switching losses. The controller relies on an autoregressive with exogenous output (ARX) model based on an adaptive linear neuron (ADALINE) network, which allows for determining the turn-on time of the active switches accurately while providing the system with the ability to adapt to distinct alignment conditions. The performance of the proposed controller is compared with that of a linear controller, which does not prove to be an effective solution if misalignment occurs. [ABSTRACT FROM AUTHOR]

The single-switch quasi-resonant inverter topology is typically favored for low-cost and low-output-power applications among the resonant inverters used in induction heating systems. Despite the low-cost advantage of the quasi-resonant inverter, the soft-switching range is quite narrow, and it is not stable depending on the electrical parameters of the load that is desired to be heated. In addition, to ensure safe operation in induction cookers, it is important to know the properties of the material from which the pan is made, the diameter of the pan, and the coverage ratio between the pan and the coil. Especially in the single-switch quasi-resonant topology, it is complicated to determine pan size and pan position compared to other topologies. On the other hand, closed-loop power control algorithms are essential for single-switch inverter applications. A big relationship exists between pan detection algorithms and closed-loop power control methods used. This study proposes six alternative methods of determining the pan–coil coverage ratio for the single-switch quasi-resonant topology used in domestic induction heating cooktops. Unlike state-of-the-art methods, the proposed methods do not increase the system's cost since they use the processor for power control, are not complicated, and provide ease of application. Each method is examined in a simulation environment and experimentally for different coverage rates and compared. As a result of the comparison, the diode conduction time method in single-switch quasi-resonant systems is the most appropriate regarding reliability and applicability. [ABSTRACT FROM AUTHOR]

In the MATLAB environment, with the help of author's code, a programming environment is developed in which the input parameters are entered, the type and structure of the inverter is selected, and the values of the circuit elements are automatically calculated. Finally, for the purpose of verification, the operation of the designed inverter is simulated. From the resulting simulation, the overall behavior of the state space variables is seen. [ABSTRACT FROM AUTHOR]

Induction heating (IH) technology is widely recognized and utilized in residential applications due to its high efficiency and safe operating characteristics. Resonant inverter circuits are widely used in IH systems because of their high efficiency and ability to perform soft switching. Among the various resonant inverters used in IH systems, the single-switch quasi-resonant (SSQR) inverter topology is typically preferred for low-cost and low-output-power applications. Despite its cost advantage, the SSQR topology has a relatively narrow soft-switching range, which can be unstable depending on the electrical parameters of the load and the resonant converter circuit. Accurately determining the capacitance value of the resonant capacitor and the inductance value of the induction coil, which are the key circuit elements of the SSQR induction cooker, is crucial for designing a reliable, efficient, and durable cooking system. In other words, there exists a critical relationship between the resonant converter circuit parameters, load characteristics, and safe operating conditions. Additionally, when considering closed-loop control methods used for power control and safety, selecting appropriate resonant circuit elements becomes vital in ensuring both reliable and efficient operation. This paper focuses on a novel and simplified design method for the SSQR inverter utilized in household appliances. The proposed method and its advantages in terms of the safe operating area of the switch are theoretically investigated and verified through simulations and prototype circuits. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) for portable electronic applications has been gaining a lot of interest over the past few decades. This study provides a comprehensive review of the recent advancements in WPT technology, along with the challenges faced in its practical implementation. The modeling and design of WPT systems, including the effect of cross-coupling in multiple receivers, have been discussed and the techniques for efficiency improvement have been highlighted. The challenges of coil design, EMI shielding, and foreign object detection have been pointed out and various cutting-edge solutions have been presented. With improvements in wide bandgap technology, there is a push to operate WPT systems at mega-hertz frequencies. The reason for this is twofold: the miniaturization of the system and the ability to achieve a better magnetic link efficiency. However, with higher frequency comes the challenge of operating the power electronic components efficiently by using soft-switching techniques. Hence, an in-depth discussion on soft-switched topologies such as the Class D and Class E converters and their variations has been provided. Finally, the effects of magnetic field exposure on humans along with safety standards have been discussed.

This article presents a class $\Phi _{2}$ inverters for high-power applications using multiple enhancement-mode gallium nitride (eGaN) switching devices operating at 13.56 MHz. The eGaN devices are beneficial in high-frequency, high-power applications such as plasma processing, thanks to the low switching and conduction losses. In addition, the small size of eGaN devices increases power density while reducing the impact of parasitic package components. However, their small package size makes it challenging to manage power dissipation, particularly at higher frequencies where additional conduction losses due to dynamic $R_{DS(on)}$ and switching losses due to $C_{OSS}$ can significantly increase power dissipation. To address these challenges, we investigate the individual contributions of dynamic $R_{DS(on)}$ and $C_{OSS}$ to power losses at high frequencies by paralleling multiple devices. We also propose criteria for selecting the optimum number of parallel eGaN devices to decrease power dissipation per device by reducing conduction losses greater than the addition in $C_{OSS}$ losses. This approach helps to alleviate thermal stress in the devices. Finally, we demonstrate the effectiveness of our approach by designing a 1 kW single inverter and a 2 kW push-pull inverter at 13.56 MHz, which achieve over 90% drain efficiency while reducing thermal stress in the device.

Induction heating offers numerous advantages over conventional methods for heating high-pressure fluids in hydraulic testing applications. It simplifies complex processes, mitigates the risks associated with high-pressure environments, and enhances overall safety. The design of an efficient induction heating system requires a clear understanding of its key components, including the resonant tank circuit, impedance matching and isolation stage, high-frequency inverter, driver circuitry, and controller. The configuration of the resonant circuit plays a crucial role in device ratings and control methods. To meet the demanding requirements of switching devices like IGBTs, the driver circuit must ensure high immunity to interferences and failure. Effective system design allows the heating circuit to operate close to resonant switching, minimizing switching losses and cooling requirements. This paper presents the design and development of a 4-kW induction heater specifically tailored for inline heating of aviation fuel under high pressure. The system aims to achieve a precise temperature profile for testing line-replaceable units (LRUs) used in aircraft. The design methodology encompasses the selection of the resonant tank circuit configuration, impedance matching and isolation stage, high-frequency inverter, driver circuitry, and control strategies. Through extensive simulations in LTspice and experimental measurements, power losses in different components of the power conversion circuits are assessed, and overall system efficiency is evaluated. The results demonstrate the proposed induction heating system's remarkable energy efficiency, reduced switching losses, and improved reliability. Furthermore, a comprehensive comparison with existing designs and industry norms is presented, highlighting the distinct advantages of the proposed system in terms of cost-effectiveness, energy efficiency, material utilization, and processing time. This research contributes valuable insights into the design and optimization of induction heating systems for high-pressure fluid heating applications, providing a practical and efficient solution for the aviation industry. [ABSTRACT FROM AUTHOR]

The harmonic and resonant characteristics of a multi-inverter grid-connected system can negatively affect power quality when weak grid conditions are present. In this paper, firstly, harmonic currents are modeled for the inverter, the correctness of low-frequency harmonics and high-frequency harmonics are verified in closed loop, and the characteristics of harmonic currents are analyzed when the parameters are varied. Secondly, the resonant characteristics of the inverter with feed-forward link are analyzed, and a multi-inverter grid-connected equivalent model based on the triple-decomposition conductance is developed and analyzed in conjunction with the resonant modal analysis method. Then, a harmonic resonance impedance reshaping method is proposed to suppress the background harmonics using improved weighted average current control (WACC), suppress the system resonance based on the point of common coupling (PCC) paralleling virtual conductance method, and improve the stability margin of the system combined with impedance reshaping resonance suppression method. Finally, simulations and comparison of results with different suppression methods verify the superiority and effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This work presents a comparative analysis and design procedure of a converter based on an LLC resonant inverter used for induction heating applications depending on the transistor technology used and the selected operating frequency. A major objective of the work is to determinate the inverter design requirements leading to the optimal sizing of the components, improving its operation and minimizing power losses. Additionally, it proposes a design to obtain a great insensitivity of the inverter operation against large variations of load impedance. This article analyzes the operation of the inverter where the power regulation is carried out by phase‐shift (PS) modulation. Simple rules are formulated for the design of the resonant circuit components. The design has been verified testing a 25‐kW inverter in an industrial application of induction hardening operating at 500 kHz. Inverter efficiency is around 98.5% when using Silicon Carbide (SiC) MOSFETs. [ABSTRACT FROM AUTHOR]

Summary: High‐frequency AC (HFAC) LCLC resonant inverter has recently received more and more attention in power distribution system (PDS) of intelligent vehicles. However, LCLC resonance complicates the design of a current control loop and can even threaten the stability and transient performance of PDS. Active damping (AD) strategies based on the feedback of a single filter voltage or current have been shown to be effective and cost‐efficient method for attenuating resonant spikes. In this paper, a notch filter‐based AD (NFAD) control strategy is proposed to improve the stability and transient performance of PDS for intelligent vehicles. By sensing and feeding back the output resonance current of LCLC resonant inverter, the NFAD control strategy is then formulated to emulate a virtual impedance in order to improve the system phase margin and crossover frequency. Hence, the proposed control strategy can not only suppress the LCLC double resonance peaks but also effectively improve the transient performance of resonant inverter while guaranteeing the stability of the system. Finally, an experimental prototype was established and tested to verify the effectiveness of the proposed control strategy with a rated output power of 130 W, an operation frequency of 25 kHz, and a sinusoidal output voltage of 28 V (rms). [ABSTRACT FROM AUTHOR]

Modeling of photovoltaic (PV) water pumping system for rural water localities is vital especially in these modern days, in Tanzania. This is due to the rise of high number of solar-powered rural water projects constructed lacking appropriate design. The fate result into poor and substandard projects delivering below expectations. Kikombo Solar Water Project situated in Dodoma; Tanzania is one among poorly designed solar project chosen as a case study to validate proposed model. The main problem of Kikombo project is unsatisfactory amount of water from domestic points to satisfy population demand. This matter has been raised by pumping-station attendants and the Kikombo village community. The Kikombo water project can only deliver 14.21 m 3 /day while required demand is 50 m 3 /day. In order to solve the existing problem, solar water pumping model was developed. It consists of PV array, a motor-pump (AC), inverters (DC–AC converter), maximum power point tracker (MPPT) integrated with a controller and a storage water tank. Analysis was done in MATLAB to estimate which parameters should be upgraded to meet the water requirements. Moreover, the input and output variable for each model component were identified and simulated in MATLAB software. Finally, PV model was validated and system capacity improvement to rectify designs limitation for Kikombo is proposed. The model results were validated through real measurement data at Kikombo water pumping station. The differential error of 0.04062 was observed as a system error. PV model displayed an error of 0.0509 for power output, 0.0383 for current and 0.0131 for voltage; inverter displayed error of 0.0686 and 0.0406 for motor pump. In order to acquire sufficient water demand of 50 m 3 /day, the PV panel and pump capacities should be increased to 8.82 kW and 7.35 kW respectively from the existing PV panel’s power of 2.5 kW and motor-pump of 4 kW. [ABSTRACT FROM AUTHOR]

Wireless power transfer (WPT) is a power transfer technique widely used in many industrial applications, medical applications, and electric vehicles (EVs). This paper deals with the dynamic modeling of the resonant inverter employed in the WPT systems for EVs. To this end, the Generalized State-Space Averaging and the Laplace Phasor Transform techniques have been the flagship methods employed so far. In this paper, the modeling of the resonant inverter is accomplished by using the novel Modulated Variable Laplace Transform (MVLT) method. Firstly, the MVLT technique is discussed in detail, and then it is applied to model a study-case resonant inverter. Finally, a study-case resonant inverter is developed and utilized to validate the theoretical results with MATLAB/Simulink.

Wireless power transfer (WPT) for portable electronic applications has been gaining a lot of interest over the past few decades. This study provides a comprehensive review of the recent advancements in WPT technology, along with the challenges faced in its practical implementation. The modeling and design of WPT systems, including the effect of cross-coupling in multiple receivers, have been discussed and the techniques for efficiency improvement have been highlighted. The challenges of coil design, EMI shielding, and foreign object detection have been pointed out and various cutting-edge solutions have been presented. With improvements in wide bandgap technology, there is a push to operate WPT systems at mega-hertz frequencies. The reason for this is twofold: the miniaturization of the system and the ability to achieve a better magnetic link efficiency. However, with higher frequency comes the challenge of operating the power electronic components efficiently by using soft-switching techniques. Hence, an in-depth discussion on soft-switched topologies such as the Class D and Class E converters and their variations has been provided. Finally, the effects of magnetic field exposure on humans along with safety standards have been discussed. [ABSTRACT FROM AUTHOR]

This paper presents a detailed review of the design aspects and performance analysis of high-frequency inverters used in inductive power transfer application (IPT) for electric vehicles. The paper's main scope is focused on the design of inverters used explicitly for wireless charging with misalignment variations and coil dimensions. The research articles in the literature focus on the high-power transfer and coil structures for the existing topologies. The magnetic resonance coupling in the IPT system depends on the resonance phenomenon. The operating frequency of the inverter must be the same as the resonant frequency in the compensation network. On complete assessments, the paper emphases on suitable inverter specifications for wireless charging and its related issues. In addition, the resonant inverters can be replaced with H-bridge inverters in consideration of voltage stress and harmonic control. Investigations on harmonic elimination strategies for H-bridge and resonant inverters are also discussed in the paper. [ABSTRACT FROM AUTHOR]

This paper proposes a 2-kW plasma power supply with a small frequency fluctuation. In existing plasma power supplies, when the input voltage is fixed, the frequency fluctuation is large according to the load impedance and output voltage of the plasma discharger, which constitutes a problem. The proposed plasma power supply addresses this problem by generating an output voltage with a small frequency fluctuation according to the load impedance and output voltage change by applying a variable input voltage and a compensation capacitor. The proposed circuit has a two-stage structure comprising a single-phase power factor correction (PFC) boost converter and a high-frequency inverter with a parallel resonant circuit. Accordingly, a prototype plasma power supply with an output voltage of 3–5 kVpk and 2-kW was designed, and its validity was verified using experimental results obtained from the proposed circuit. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a novel single-phase modified Vienna rectifier (MVR) for the harmonic mitigation and power factor improvement of an induction heating (IH) system. The latter employs a high-frequency resonant inverter that is responsible for the generation of high-frequency harmonics, which, in turn, deteriorates the power quality. This mitigation must be done in accordance with harmonic regulations such as IEEE Std. 519-2014,IEC-555, and EN 61000-3-2, etc. Consequently, an MVR is placed between the power supply and the IH system. The proposed novel MVR topology overcomes the limitations of conventional Vienna rectifiers, such as their unbalanced voltage across output capacitors, high ripple at the output DC bus, and high THD in the supply current, etc. The efficacy of the proposed model has been verified by a series of simulations in PSIM. It is followed by a hardware validation using an Arduino Uno ATmega328 digital controller on a 1.2 kW experimental prototype of the IH system. The simulation and experimental results of the power quality indices comply with the IEEE-519 standards. [ABSTRACT FROM AUTHOR]

The higher frequency electromagnetic (EM) emission in low voltage power systems is rising continuously due to the increasing use of modern electronic devices. The electronic ballast of a compact fluorescent lamp (CFL) is one of the sources of conducted EM emission in the power system. Conducted EM emission measurements are performed on compact fluorescent lamps (CFL) in the range of 2–150 kHz and compared with simulation results. The LTSpice simulation of typical 11W compact fluorescent lamps is used to analyze the measured values. Comparisons are made in both the time and frequency domains. The EMI filter in the ballast circuit can reduce the level of high-frequency EM emission. However, in order to get a more accurate result, it is necessary to find out the main cause of conducted EM emission in the ballast circuit, as the HF distortion spreads through the LV network in current signal between electronic devices.