Inverter For Induction Heating Research Articles

A Novel Multiple-Frequency Resonant Inverter for Induction Heating Applications

This paper presents a novel multiple-frequency resonant inverter for induction heating (IH) applications. By adopting a center tap transformer, the proposed resonant inverter can give load switching frequency as twice as the isolated-gate bipolar transistor (IGBT) switching frequency. The structure and the operation of the proposed topology are described in order to demonstrate how the output frequency of the proposed resonant inverter is as twice as the switching frequency of IGBTs. In addition to this, the IGBTs in the proposed topology work in zero-voltage switching during turn-on phase of the switches. The new topology is verified by the experimental results using a prototype for IH applications. Moreover, increased efficiency of the proposed inverter is verified by comparison with conventional designs.

Simulation of MOSFET Based Inverter for Induction Heating In MATLAB

Simulation of MOSFET Based Inverter for Induction Heating In MATLAB

The advantages of robust control of pulse amplitude modulation series-parallel load induction heating inverters

Summary The goal of this paper is to present to the research community the benefit of utilizing advanced control methods for induction heating inverters in comparison with the existing classical control methods and to promote their application. For this purpose, a robust controller and a classical PI controller for application in a high-power series–parallel load induction heating inverter has been designed. For the robust controller designed, the series–parallel load inverter model is augmented with additive and multiplicative uncertainties for nonmagnetic material heating, and the H∞ algorithm is utilized. To highlight the advantages of the robust controller designed in this research study, a comparison is made with the classical PI controller system. Copyright © 2015 John Wiley & Sons, Ltd.

A Load-Power Adaptive Dual Pulse Modulated Current Phasor-Controlled ZVS High-Frequency Resonant Inverter for Induction Heating Applications

A new prototype of an efficiency-improved zero voltage soft-switching (ZVS) high-frequency resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the dual pulse modulation mode (DPMM) that incorporates a submode power regulation scheme such as pulse density modulation, pulse frequency modulation, and asymmetrical pulse width modulation into main one of the resonant current phase angle difference ( θ) control, the IH load power can be widely regulated under the condition of ZVS, while significantly improving the efficiency in the low output power setting. The essential performances on the output power regulations and ZVS operations with the DPMM schemes are demonstrated in an experiment based on a 1 kW-60 kHz laboratory prototype of the ZVS HF-R inverter. The validity of each DPMM scheme is originally compared and evaluated from a practical point of view.

A New Current Phasor-Controlled ZVS Twin Half-Bridge High-Frequency Resonant Inverter for Induction Heating

A novel soft-switching high-frequency (HF) resonant (HF-R) inverter for induction heating (IH) applications is presented in this paper. By adopting the current phasor control of changing a phase shift (PS) angle between two half-bridge inverter units, the IH load resonant current can be regulated continuously under the condition of wide-range soft-switching operations. In addition to this, the dual-mode power regulation scheme-based PS angle control and asymmetrical pulsewidth modulation in one inverter unit is proposed for improving the efficiency in low output power settings. The essential performances on the output power regulation and soft-switching operations are demonstrated in an experiment using its 1-kW 60-kHz HF-R inverter prototype, and then, the topological validity is evaluated from a practical point of view.

ZVS single-switch inverter for induction heating – optimum operation

The optimum operation of a single-switch class E transistor inverter for induction heating has been discussed in the paper. The graphs of the most important inverter parameters as a function of the values of the resonant circuit components are shown. The results presented have been illustrated with some current and voltage waveforms obtained on the basis of mathematical analysis as well as using IsSpice simulation program. A concept of a control system has also been presented, which should ensure nearly optimum operation of the inverter. Streszczenie. W artykule omowiono prace optymalną jednolącznikowego tranzystorowego falownika klasy E do nagrzewania indukcyjnego. Przedstawiono wykresy najwazniejszych parametrow falownika w funkcji wartości elementow obwodu rezonansowego. Podano przykladowe przebiegi czasowe prądow i napiec w falowniku otrzymane zarowno na podstawie analizy matematycznej, jak i poprzez symulacje w programie IsSpice. Przedstawiono rowniez koncepcje ukladu sterowania falownika, ktory powinien zapewniac prace w warunkach bliskich optymalnym. (Jednolącznikowy falownik z przelączaniem ZVS do nagrzewania indukcyjnego praca optymalna)

Adaptive control in series load PWM induction heating inverters

Permanent variations of the electric properties of the load in induction heating equipment make difficult to control the plant. To overcome these disadvantages, the authors propose a new approach based on adaptive control methods. For real plants it is enough to present desired performances or start-up variables for the controller, from which the algorithms tune the controllers by itself. To present the advantages of the proposed controllers, comparisons are made to a PI controller tuned through Ziegler–Nichols method.

New Control Strategy for High-Frequency Digital Inverter Power Supply

The inverter power supply system has strong nonlinearity and parameter variability, especially in the non-linear loads, conventional control technology is difficult to achieve effective control and get the ideal control effect. Aiming at the control requirements of single-phase high-frequency induction heating inverter supply power control applications, uses a novel multiple and composite control technologies to achieve rapid power modulation control of inverter. The components and design principles of proposed control system were introduced in detail. The inverter power system model based on the new control strategy has been built, and inverter prototype used for high-frequency induction heating was designed. The experimental results show that the proposed control method to obtain better dynamic characteristics than the conventional control technologies, and has good advantages of system steady-state accuracy, robustness and control qualities, which has wide range of application.

A 25 kW, 25 kHz Induction Heating Power Supply for MOVPE System Using L-LC Resonant Inverter

A topology named L-LC resonant inverter (RI) for induction heating (IH) applications takes most of the merits of the conventional series and parallel resonant schemes, while eliminating their limitations. In this paper, fundamental frequency AC analysis of L-LC RI is revisited, and a new operating point is suggested featuring enhanced current gain and near in-phase operation as compared to the conventional operating point. An approximate analysis of the circuit with square-wave voltage source is also described highlighting the effect of auxiliary inductor on the source current waveform. The analysis also leads to an optimum choice of the auxiliary inductance. The requirements of the metal organic vapour phase epitaxy (MOVPE) system in which a graphite susceptor is required to be heated to 1200°C demanding a 25 kW, 25 kHz IH power supply, the configuration of developed IH system, and experimental results are presented.

A Current-Fed Parallel Resonant Push-Pull Inverter with a New Cascaded Coil Flux Control for Induction Heating Applications

This paper presents a cascaded coil flux control based on a Current Source Parallel Resonant Push-Pull Inverter (CSPRPI) for Induction Heating (IH) applications. The most important problems associated with current source parallel resonant inverters are start-up problems and the variable response of IH systems under load variations. This paper proposes a simple cascaded control method to increase an IH system's robustness to load variations. The proposed IH has been analyzed in both the steady state and the transient state. Based on this method, the resonant frequency is tracked using Phase Locked Loop (PLL) circuits using a Multiplier Phase Detector (MPD) to achieve ZVS under the transient condition. A laboratory prototype was built with an operating frequency of 57-59 kHz and a rated power of 300 W. Simulation and experimental results verify the validity of the proposed power control method and the PLL dynamics.

Embedded controlled low‐frequency AC to high‐frequency AC converter fed induction heater

PurposeThe purpose of this paper is to present, a novel boost‐active clamp bridge single stage high‐frequency zero voltage soft‐switching‐pulse width modulation (ZVS‐PWM) inverter, which converts the utility frequency AC power into high‐frequency AC power with an embedded controller. This single stage high‐frequency inverter is composed of a single‐phase diode bridge rectifier, a non‐smoothing filter, a boost‐active clamp bridge type ZVS‐PWM high‐frequency inverter, and an induction‐heated load with planar type litz wire working coil assembly. Also, the paper discusses how to extend the soft‐switching operation ranges and improve power conversion efficiency.Design/methodology/approachThe proposed converter is simulated and it is implemented using embedded controller.FindingsIt was found that the single stage high‐frequency induction heating (IH) inverter using boosted voltage function can eliminate the DC and low‐frequency components of the working coil current and reduce the power dissipation of the circuit components and switching devices.Originality/valueThe paper shows that the PWM HF inverter is preferred for IH, since it has reduced switching losses and switching stresses. The paper can be extended to PC‐based wireless control, which can be part of a distributed control system in major industrial heating systems.

Adjustable High Frequency Quasi-Resonant Inverter for Induction Heating

This paper presents the considerations of driving the Adjustable Frequency Quasi- Resonant Inverter Circuit in the high frequency. This inverter is requested to output frequency from 160kHz to 400kHz. Resonant inverter used for metalworking by the induction heating. In induction heating, high frequency can heat the shallow point, and low frequency can heat the deep point. So when heated depth is replaced, the frequency that inverter must output is different. It is necessary for the inverter to output two or more frequencies. In addition, in the heat-treatment called the hardening, only the metal surface must be heated. So, to heat-treat metal that a radius is small, it is necessary for the inverter to output high frequency. This inverter can output the frequency more than 100kHz by using Power Metal Oxide Semiconductor Field Effect Transistor (MOSFET) as power device. The circuit includes the first resonant capacitor and second one with a one-way short-circuit switch. Because synthetic series capacitance is varied by manipulating the switch, this inverter can change a period during a half period. We confirmed this inverter can output an arbitrary frequency by the experiment.

Efficiency-Oriented Design of ZVS Half-Bridge Series Resonant Inverter With Variable Frequency Duty Cycle Control

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The efficiency of zero voltage switching half-bridge series resonant inverter can be decreased under certain load conditions due to the high switching frequencies required. The proposed variable frequency duty cycle (VFDC) control is intended to improve the efficiency in the medium and low output power levels because of the decreased switching frequencies. The study performed in this letter includes, in a first step, a theoretical analysis of power balance as a function of control parameters. In addition, restrictions due to snubber capacitors and deadtime, and variability of the loads have been considered. Afterward, an efficiency analysis has been carried out to determine the optimum operation point. Switching and conduction losses have been calculated to examine the overall efficiency improvement. VFDC strategy efficiency improvement is achieved by means of a switching-frequency reduction, mainly at low-medium power range, and with low-quality factor loads. Domestic induction heating application is suitable for the use of VFDC strategy due to its special load characteristics. For this reason, the simulation results have been validated using an induction heating inverter with a specially designed load. </para>

パルス密度変調制御ワンステージソフトスイッチング高周波共振型インバータ

This paper presents a novel high frequency (HF) full bridge (FB) inverter for induction heating (IH) applications. The newly proposed FB inverter can convert utility frequency (UF) AC into DC, and DC into HFAC with one-stage power conversion. Simultaneously, the proposed inverter has a PFC function so that the terminal voltage of DC-link-capacitor is boosted all the time, and the current is passed through only one diode component of the diode bridge rectifier by the work of boost-inductor. Therefore, there are some benefits such as minimizing the number of circuit components to use as well as the conduction power losses. The output power of the proposed FB inverter is controlled by Pulse Density Modulation (PDM) scheme, and each switch comprising the inverter legs achieves Zero Voltage-Switching (ZVS) . This paper verifies these beneficial characteristics of the proposed HF one-stage inverter by simulation analyses.

Power Supply for Variable Frequency Induction Heating Using MERS Soft-Switching High Frequency Inverter

Variable frequency induction heating has great potential for industrial heating applications due to the possibility of achieving heating distribution control; however, large-scale induction heating with variable frequency has not yet been introduced for practical use. This paper proposes a high frequency soft-switching inverter for induction heating that can achieve variable frequency operation. One challenge of variable frequency induction heating is increasing power electronics ratings. This paper indicates that its current source type dc-link configuration and soft-switching characteristics can make it possible to build a large-scale system with variable frequency capability. A 90-kVA 150-1000Hz variable frequency experimental power supply for steel strip induction heating was developed. Experiments confirmed the feasibility of variable frequency induction heating with proposed converter and the advantages of variable frequency operation.

誘導加熱用バイパス形ZVS-PWM高周波インバータ

In this paper, we present a novel circuit topology for achieving thezero-voltage switching (ZVS) operation in a high-frequency inverter. The output power of the inverter is regulated over a wide range using a pulse widthmodulation (PWM) technique and by connecting a bypass circuit to a conventional single-ended push-pull (SEPP) high-frequency inverter for induction heating. All the switching devices of the proposed inverter are operated in the ZVS mode.

Load-Adaptive Control Algorithm of Half-Bridge Series Resonant Inverter for Domestic Induction Heating

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Domestic induction cookers operation is based on a resonant inverter which supplies medium-frequency currents (20–100 kHz) to an inductor, which heats up the pan. The variable load that is inherent to this application requires the use of a reliable and load-adaptive control algorithm. In addition, a wide output power range is required to get a satisfactory user performance. In this paper, a control algorithm to cover the variety of loads and the output power range is proposed. The main design criteria are efficiency, power balance, acoustic noise, flicker emissions, and user performance. As a result of the analysis, frequency limit and power level limit algorithms are proposed based on square wave and pulse density modulations. These have been implemented in a field-programmable gate array, including output power feedback and mains-voltage zero-cross-detection circuitry. An experimental verification has been performed using a commercial induction heating inverter. This provides a convenient experimental test bench to analyze the viability of the proposed algorithm. </para>

Design of the L-LC Resonant Inverter for Induction Heating Based on Its Equivalent SRI

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents the new <emphasis emphasistype="boldital">L</emphasis>-<emphasis emphasistype="boldital"> LC</emphasis> induction heating generator and probes that, in resonance, are equivalent to a series resonant inverter. This equivalence is then used to compare both topologies, extracting the advantages and disadvantages of the <emphasis emphasistype="boldital">L</emphasis>-<emphasis emphasistype="boldital">LC</emphasis> usage. In addition, based on this equivalence, a design procedure is proposed that covers all possible <emphasis emphasistype="boldital">L</emphasis>-<emphasis emphasistype="boldital">LC</emphasis> configurations. Finally, some experimental results are presented, showing waveforms during normal and short-circuit operation. </para>

Analysis of Circuit Operation under ZVS and NON-ZVS Conditions in Phase-Shift Inverter for Induction Heating

This paper presents a detailed analysis of circuit operation under ZVS and NON-ZVS conditions in a full-bridge high-frequency phase-shift control series resonant MOSFET inverter with the load of induction heating. Various modes of circuit operation both under ZVS and NON-ZVS conditions are first analyzed in details. The voltage and current equations of these circuits are then obtained and used for calculation of the waveforms by MATLAB program. The calculated results can lead to the consideration of various circuit parameters that determine ZVS or NON-ZVS operating conditions. The theoretical results are also verified by experimental ones, using a prototype test set rated at 3kW.

Soft Switching SEPP High Frequency Inverter for Induction Heating

This paper presents a novel circuit topology to attain soft switching operation of a high frequency inverter. Its output power is regulated over a wide range using a PWM control technique by connecting an auxiliary resonant circuit to the conventional single ended push pull (SEPP) high frequency inverter for induction heating. All switching devices in the proposed inverter are operated soft switching mode. This paper describes its circuit constitution and obtained experimental results from a practical point of view.