Induction Heating Power Supply Research Articles

Improved Litz wire manufacture process using resonant power converter-based induction heating

PurposeLitz wire manufacturing using mechanical procedures presents several limitations regarding reliability and repeatability, especially when a small strand diameter is used. This paper aims to propose a power supply design for Litz wire manufacturing using a high-frequency high-performance resonant converter.Design/methodology/approachThis paper proposes the design of a resonant power supply for induction heating specially designed to tackle with the challenge of heating Litz wires quickly.FindingsThe proposed converter enables the removal of the isolating coating from the Litz wire through induction heating, improving significantly the manufacturing process.Originality/valueThe proposed converter improves significantly the manufacturing process of Litz wire through induction heating, with economic and reliability benefits.

Design of power converters for induction heating applications taking advantage of wide-bandgap semiconductors

PurposeWide-bandgap (WBG) semiconductors have emerged as a disruptive technology in the power electronics sphere. This paper aims to analyse and discuss the importance for induction heating systems and gives some examples and highlights some future design trends and perspectives.Design/methodology/approachThe benefits of WBG semiconductors are reviewed with a special emphasis on induction heating applications.FindingsWBG devices enable the design of higher-performance induction heating power supplies. A significant selection of the reported converters is discussed, highlighting the benefits of this technology.Originality/valueThis paper highlights the benefits of WBG semiconductors and their potential to change and improve induction heating technology in the next years.

Hierarchical Direct Power Control of Modular Multilevel Converter for Tundish Heating

In this paper, the full bridge-based modular multilevel converter (MMC) is discussed for the application of tundish induction heating power supply (TIHPS). TIHPS features three-phase to single-phase ac/ac conversion and variable output frequency, and has intense demand for the power transmission stability and output current control precision. MMC is suitable for this application and especially the bulky and costly transformer and ac filter in the conventional topology can be dispensable. Therefore, it is interesting to investigate the applicable control method for MMC-TIHPS. According to the instantaneous power theory, a hierarchical direct power control based on the improved deadbeat current control is presented to assure the energy balance inside and outside MMC-TIHPS and reduce the sensitiveness of the current controller to parameter uncertainties. The proposed control strategy dispenses with the phase-locked loop, and does not exist the coupling among control variables of internal and external currents. Then, parameters design of energy controller is studied for stability analysis. Finally, MMC-TIHPS and proposed control method are verified by experimental results of a down-scaled physical prototype.

Indigenous development of induction skull melting technology for electromagnetic processing of refractory and reactive metals and alloys

As a part of the indigenous development of the Induction Skull Melting (ISM) technology, a set of numerical simulations was carried out initially to arrive at the design parameters of a segmented cold crucible. Based on these parameters, an ISM facility comprising a water-cooled segmented copper crucible with in-situ casting module, induction heating power supply system, cooling water recirculation system, vacuum chamber with vacuum delivery system and associated instrumentation & control units was built. The ISM facility was successfully tested for melting and homogenizing different metals and alloys.

Approximate analytical solution for induction heating of solid cylinders

An approximate solution to the mathematical model for induction heating of a solid cylinder in a cylindrical induction coil is presented here. The coupled multiphysics model includes equations describing the electromagnetic field in the heated object, a heat transfer simulation to determine temperature of the heated object, and an AC circuit simulation of the induction heating power supply. A multiple-scale perturbation method is used to solve the multiphysics model. The approximate analytical solution yields simple closed-form expressions for the electromagnetic field and heat generation rate in the solid cylinder, for the equivalent impedance of the associated tank circuit, and for the frequency response of a variable frequency power supply driving the tank circuit. The solution developed here is validated by comparing predicted power supply frequency to both experimental measurements and calculated values from finite element analysis for heating of graphite cylinders in an induction furnace. The simple expressions from the analytical solution clearly show the functional dependence of the power supply frequency on the material properties of the load and the geometrical characteristics of the furnace installation. The expressions developed here provide physical insight into observations made during load signature analysis of induction heating.

Modeling and Simulation of PLL-Controlled Circuit of Series Resonant Inverter in High Frequency Induction Heating

This paper analyses the necessity of PLL (Phase Locked Loop-controlled) circuit for series resonant inverter in high frequency induction heating power supply. We were interested in modeling and simulation of an inverter with SIT (Static Induction Transistor) functioning at resonance and intended for the induction heating of high frequency ferromagnetic cylindrical piece. During the heating of the ferromagnetic piece, the resistive and inductive equivalent parameters of the inductor-load varied with the temperature. Thus it became necessary to vary the frequency of operation of the inverter to maintain the resonance. An order by PLL was employed for the continuation of the frequency resonance. The model simulation of the resonant inverter series model was established in MATLAB/Simulink. The simulation results indicate that this circuit can keep the power-factor angle just changing within an acceptable range. It can guarantee the inverter to operate in the small-inductive condition, reduce the switching losses of SITs, and enhance the security of the power supply. Also, the obtained results show that the proposed electrical circuit track perfectly the resonance frequency even around the Curie temperature of the material despite the large variation of the frequency near the Curie point.

CFAVC scheme for high frequency series resonant inverter-fed domestic induction heating system

This article presents the investigations on the constant frequency asymmetric voltage cancellation control in the AC–AC resonant converter-fed domestic induction heating system. Conventional fixed frequency control techniques used in the high frequency converters lead to non-zero voltage switching operation and reduced output power. The proposed control technique produces higher output power than the conventional fixed-frequency control strategies. In this control technique, zero-voltage-switching operation is maintained during different duty cycle operation for reduction in the switching losses. Complete analysis of the induction heating power supply system with asymmetric voltage cancellation control is discussed in this article. Simulation and experimental study on constant frequency asymmetric voltage cancellation (CFAVC)-controlled full bridge series resonant inverter is performed. Time domain simulation results for the open and closed loop of the system are obtained using MATLAB simulation tool. The simulation results prove the control of voltage and power in a wide range. PID controller-based closed loop control system achieves the voltage regulation of the proposed system for the step change in load. Hardware implementation of the system under CFAVC control is done using the embedded controller. The simulation and experimental results validate the performance of the CFAVC control technique for series resonant-based induction cooking system.

Performance of Induction Heating Power Supply Using Dual Control Mode Pulse-width Modulation–Pulse-density Modulation High-frequency Inverter

This article presents a novel induction heating power supply. The power supply is based on an auxiliary active edge resonant zero-current soft-switching technique. It consists of single-ended push–pull series load resonant inverter. The proposed inverter is cost effective for high-frequency induction heating consumer appliances. The new multi-resonant high-frequency inverter with series load resonance and edge resonance can regulate its high-frequency output power under the constant-frequency zero-current soft-switching commutation principle on the basis of an asymmetrical pulse-width modulation control scheme. The brand-new consumer induction heating product is evaluated and discussed on the basis of simulation and experimental results. To extend zero-current soft-switching operation ranges under a low-power setting as well as improve efficiency, the high-frequency pulse-density modulation strategy is demonstrated for a high-frequency soft-switching inverter. Its practical effectiveness of induction heating power supply is substantially proved from an induction heating application point of view.

Power Tracking Control of Domestic Induction Heating System using Pulse Density Modulation Scheme with the Fuzzy Logic Controller

Power requirement to the induction heating system varies during the heating process. A closed loop control is required to have a smooth control over the power. In this work, a constant frequency pulse density modulation based power tracking control scheme for domestic induction heating system is developed using the Fuzzy Logic Controller. In the conventional power modulation schemes, the switching losses increase with the change in the load. The proposed pulse density modulation scheme maintains minimum switching losses for the entire load range. This scheme is implemented for the class-D series resonant inverter system. Fuzzy logic controller based power tracking control scheme is developed for domestic induction heating power supply for various power settings. The open loop and closed loop simulation studies are done using the MATLAB/Simulink simulation tool. The control logic is implemented in hardware using the PIC16F877A microcontroller. Fuzzy controller tracks the set power by changing the pulse density of the gate pulses applied to the inverter. The results obtained are used to know the effectiveness of the fuzzy logic controller to achieve the set power.

10KW/100KHZ High Frequency Induction Heating Power Supply Design

TMS320F2812 was taken as the main controlling chip, MOSFET was taken as the inverter switching device and IGBT was taken as the chopper switching device in the system. This paper introduced the main topology circuit design and circuit components selection.In the process of heating, double-closed loop control strategy fuzzy and DPLL (Digital Phase Locked Loop) was adopted. The simulation model of induction heating power system was built in SIMULINK platform. The simulation results indicate that the load frequency automatic tracking and closed-loop power control are realized. The time to steady output is about 0.1ms. Finally, built the 10kW/100kHZ induction heating power supply experimental platform, As can be seen from the experimental waveforms, the equivalent impedance of the load can always be weakly perceptual state.

Study of Induction Heating Power Supply Based on 74HC4046

According to the change of resistivity and magnetic permeability of iron load which will influence the resonance frequency in the process of induction heating, this paper presents a frequency tracking system based on the 74HC4046. It can control the output frequency of the power supply in real time, and make the power output frequency to trace the resonance frequency of load. This paper also analyses the phase compensation of the control system, and proposes a new way of phase compensation. The corresponding simulation experiment is done finally. It provides the theory basis to analyze and design an inverter power supply.

The Design of Digital Medium Frequency Induction Heating Power Supply Based on DSP and FPGA

DSP (XC2267) is the main control chip which does the increment PI algorithms and realizes the voltage and current double closed-loop. Three-phase thyristor rectifier method based on the phase self-adjusting of FPGA is proposed. A method for swept-frequency start circuit is designed to implement the transition between the high-power and low-power. The invert system uses the compound control of improved PWM and frequency phase lock to improve the control accuracy and efficiency. Lastly, by using bench, the circuit is tested and the feasibility and effectiveness of the whole system are verified.

The Application of Phase-Locked Loop Frequency Tracking in the Intelligence-Type Induction Heating Power Supply

As the induction heating power was working, its load resonant frequency constantly changes. In order to improve the efficiency of power supply, it requires that the inverter output frequency can follow changes in natural frequency of the load, namely the frequency tracking control. Aiming at the deficiency of the frequency tracking control system, this paper presents a method that the phase locked loop (PLL) tracking system works on real-time control of the output frequency of the power supply,and introduces a phase locked mathematical model which fits the inverter power supply, and offers a simulated analysis by using PSPICE. Through experiments, the system proves to be good at frequency tracking.

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.

Based on the Repetitive Controller for Induction Heating Power Supply

According to the electromagnetic induction heating power supply control system, puts forward a kind of proportion, integral, differential regulator with repetitive controller combined control strategy, in order to improve the heating process of the power supply output quality. Based on this control strategy, gives the repetitive controller each part parameters of the detailed design scheme and proportion, integral and differential controller coefficient; Construction of compensator Q(z) and S(z) , the introduction of zero phase shift Notch function, effectively inhibit PWM-type induction heating power supply output voltage harmonic interference. To carry out the simulation experiment, the results show that the proposed controller can guarantee that the system has better dynamic and static properties, error convergence rate is greatly improved.

The Application of SG3525 Pulse Width Modulator in Intermediate Frequency Induction Heating Power Supply

In This paper, we introduce a kind of intermediate frequency induction heating power supply integral design based on the pulse width modulator SG3525, analyse SG3525, KA962F driving chip, the main circuit structure and function and realize frequency and occupies emptiescompared independent can be adjusted. The main circuit adopts the series resonant type IGBT half bridge inverter circuit. It outputs pulse with difference of two phases of 180 degrees to the IGBT driver board through the SG3525, IGBT driver board receives the pulse and drive the IGBT main circuit. Circuit adds the limit frequency protection circuit design, so that the heating power supply works in the inductive state. To improve the on-site operation safety.Finally the unit circuit experiment is conducted on the basis of the field experiment, it is proved that the whole design scheme is feasibility by experiments.

A Design of Cascaded Multilevel Inverter Snubber Circuit

The high frequency induction heating power supply has received increasing attention from researchers, multilevel converter is a high voltage large power application areas of research focus and core, it solves the problem of the multilevel inverter output voltage waveform adjustment, avoids the problem of two times reversing that the load voltage in the commutation during the dead period occurred. An effective way to improve efficiency is to keep the power device of low voltage stress and less switching loss. A passive lossless snubber circuit is designed for inhibiting the reverse recovery current of diode and improving the turn-on condition of powers switch. The operation process of snubber circuit is analyzed and the parameter design method is given. The results of simulation have verified the validity of design methods and the conclusions given by theoretically analyzing in this paper.

Research and Design on IGBT Induction Heating Power Supply

This paper introduces a new method, using PLL and fixed angle control, to track the converter's frequency automatically. After analyzing the work state of parallel inverter, a new control method using closed-loop rectifier control of voltage and current. The commonly-happening faults in the IGBT Medium Frequency Induction Heating Power Supply is analyzed, and the corresponding protective measures and protection circuits are designed. 100kw / 8kHz Parallel induction heating power is developed, and the designed control method is verified to be scientific and effective.

The Study of Phase-shift Super-Frequency Induction Heating Power Supply

This paper combines pulse-width phase-shift power modulation with fixed-angle phase-locked-control to adjust the inverter's output power, this method not only meets the work conditions of voltage inverter, but also realizes the large-scale of power modulation, and the main circuit is simple, the switching devices realize soft switching. This paper analyzes the relationship between the output power and phase-shift angle, the control strategy is simulated by Matlab/Simulink, and the results show that the method is feasible and meets the theoretical analysis

An Improved Design of Controller for Medium Frequency Induction Power

Present a variety of advanced PID control algorithm in the use of induction heating power supply is increasingly broad, achieving good results in self-tuning of PID parameters. However, most of the output of PID control value is a single volume, such as DC power regulator for controlling the output voltage of rectifier or inverter power regulator for controlling the output frequency of inverter current. It has achieved a certain effect in the heat treatment process control, but did not take into account the actual efficiency of the power. The two adjustments will be combined in this article, using Smith prediction control algorithm and methods based on the Ziegler-Nichols PID tuning algorithm for time delay system. Both of the raising of induction power efficiency and lower system energy consumption has been achieved.