Search results for "Induction heating"
showing 9 items of 19 documents
Automated Calculation Method to Determine the Output Power Based on the Frequency for Induction Heating IGBT Parallel Inverter
2007
The fact that some inverter topologies used in induction heating applications allow the soft switching working operation lets the progressive replacement of the MOSFET with the IGBT in high power inverters. This is due to two main reasons, the former is the IGBT reliability and the latter is the ratio defined as the price of the component per output power. In this article an automated method to determine the output power based on the frequency of an inverter build with different IGBT is described. To carry out this method is necessary to define the power cycle and to develop the calculation process which determines the energy losses in the working conditions of the resonant parallel inverte…
A mathematical simulation of high temperature induction heating of electroconductive solids
2007
The mathematical model of non-stationary coupled electromagnetic and thermal processes in polarizable and magnetizable axisymmetric electroconductive solids subjected to electromagnetic field generated by external currents is proposed. The processes parameters are connected through heat sources and temperature dependence of material characteristics. The problem is solved by finite element method. The process of induction heating of a finite steel cylinder is considered.
The Nukiyama Curve in Water Spray Cooling: its Derivation from Temperature-Time Histories and its Dependence on the Quantities that Characterize Drop…
2007
Abstract Heat transfer from hot aluminium walls to cold water sprays was investigated. The method used was the transient two-side symmetric cooling of a planar aluminium target, previously heated to temperatures of up to 750 K, by twin sprays issuing from full-cone swirl spray nozzles of various gauge. The target’s mid-plane temperature was recorded during the cooling transient by thin-foil K thermocouples and a high-frequency data acquisition system. In order to determine the wall temperature Tw, the wall heat flux q w ″ and the q w ″ - T w heat transfer (Nukiyama) curve, two different approaches were used: the first was based on the solution of an inverse heat conduction problem, the seco…
Simple Lossless Inductive Snubbers-Assisted Series Load Resonant Inverter Operating under ZCS-PDM Scheme for High-Frequency Induction Heating Fixed R…
2022
This paper presents a high-frequency pulse-density-modulated (PDM) soft-switching series load resonant inverter for use in induction heating (IH) fixed roller applications, which is used in copy and printing machines. The proposed simple high-frequency resonant inverter uses an asymmetrical pulse pattern PDM control scheme to achieve complete zero-current soft-switching commutations over a wide output range of input power regulation. Additionally, when the printer toner requires operation in very light load conditions, this causes difficulty in achieving zero-voltage or zero-current soft-switching operations in the IH high-frequency resonant inverters with pulse frequency modulation or puls…
Study of TiO2 nanomembranes obtained by an induction heated MOCVD reactor
2015
Abstract Nanostructures of TiO2 were grown using the metal oxide chemical vapor deposition (MOCVD) technique. The procedure used induction heating on a graphite susceptor. This specific feature and the use of cobalt and ferrocene catalysts resulted in nanomembranes never obtained by common MOCVD reactors. The present study discusses the preparation of TiO2 nanomembranes and the dependence of nanomembrane structure and morphology on growth parameters.
Magnetically Induced Cavitation for the Dispersion of Particles in Liquid Metals
2018
A contactless excitation of cavitation is possible by superposition of induction heating with a static axial magnetic field. This creates an alternating electromagnetic body force in a liquid metal which in turn produces pressure oscillations. Using this method, the onset of cavitation has been clearly observed in various liquid metals (tin, zinc, aluminum, steel SAE 304) at pressure oscillations in the range of 28…50 kPa. The present study aims to extend the previous work by producing steel metal matrix composites (MMC) and assessing the feasibility of the proposed method for particle dispersion in steel. Stainless steel (SAE 316L) samples with different ceramic inclusions, e.g. TiN, Al2O3…
Rapid nanocrystallization of soft-magnetic amorphous alloys using microwave induction heating
2009
The crystallization of Fe73Nb3Cu1Si16B7 alloy during microwave heating was investigated in situ using synchrotron radiation powder diffraction. The phase transformation comprises a primary nanocrystallization stage and a final microcrystallization step. We provide evidence for a strong enhancement of the transformation kinetics. Microwave heating occurs as a result of both ohmic and magnetic losses induced by eddy currents, which defines a volumetric microwave induction heating process. Nanocrystallization is completed within 5 s, while full crystallization is achieved in less than 10 s.
Using Pulse Density Modulation to Improve the Efficiency of IGBT Inverters in Induction Heating Applications
2007
This paper analyses a high power (50 kW), high frequency (150 kHz) voltage fed inverter with a series resonant load circuit for industrial induction heating applications which is characterized by a full bridge inverter made with IGBT and the power control based on pulse density modulation (PDM). This power control strategy allows that the inverter works close to the resonance frequency for all output power levels. In this situation zero-voltage switching (ZVS) and zero-current switching (ZCS) conditions are performed and the switching losses are minimized. The results are verified experimentally using a prototype for induction hardening applications. A comparative study between the PDM and …
Series and parallel resonant inverters for induction heating under short-circuit conditions considering parasitic components
1999
Series and parallel resonant inverters are the common structures in high power industrial generators for induction heating applications. In practical working conditions, short-circuit of the heating coil is very common, normally producing overvoltages that can damage the power transistors of the inverter if no special precautions are taken. The aim of the paper is to show the mechanism of how overvoltages are generated under short-circuit conditions of the heating coil for series and parallel inverters.