Control Algorithm for Microwave Sintering in a Resonant System

Alliouat, M.; Lecluse, Yves; Massieu, Jean‐François; Mazo, L. A.

doi:10.1080/08327823.1990.11688106

Cited by 5 publications

(3 citation statements)

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“…The issue of power or temperature control that would prevent heating instabilities has received considerable attention, resulting in the development of control algorithms for the feedback‐loop automatic power control systems . The temperature oscillations and limit cycles that may occur in the feedback‐controlled microwave processing systems have been analyzed in Refs.…”

Section: Heat Transfer Aspects and Sintering Simulationsmentioning

confidence: 99%

Microwave Sintering: Fundamentals and Modeling

2013

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This paper reviews the basic physical notions underlying microwave sintering and the theoretical and numerical models of the microwave sintering process. The propagation and absorption of electromagnetic waves in materials, and the distribution of electromagnetic field in cavity resonators that serve as applicators for microwave processing are discussed and the electromagnetic modeling of such applicators is reviewed. The microwave absorption properties of ceramic and metal powder materials and the methods of their description are addressed. Self‐consistent electromagnetic and thermal models that are capable of predicting the temperature distribution in the microwave‐heated materials and dynamic effects such as thermal runaway instabilities are reviewed. The multiphysics simulations that combine electromagnetic, thermal, and sintering models and result in predicting densification, shrinkage, and grain structure evolution are discussed in detail. The significance of microwave nonthermal effects in sintering is demonstrated based on the experimental results, and the models of such effects are reviewed.

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Section: Heat Transfer Aspects and Sintering Simulationsmentioning

confidence: 99%

Microwave Sintering: Fundamentals and Modeling

2013

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“…Straightforward manipulation of (7) leads to (10) indicating that the possible values of and lie on a circle of radius 1/2 , centered on the point , as shown in Fig. 3.…”

Section: B State-space Modelmentioning

confidence: 99%

“…The use of matching circuits is common in radio communications for matching amplifier resistances to antennas and to a lesser extent, in microwave engineering [8]- [10]. At radio frequencies, matching circuits take the form of ladder networks of (ideally) lossless reactances [11].…”

Section: Introductionmentioning

confidence: 99%

Design of matching circuit controllers for radio-frequency heating

Cottee

Duncan

2003

IEEE Trans. Contr. Syst. Technol.

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Electromagnetic energy in the microwave and radiofrequency (RF) portions of the spectrum can be used to heat or defrost (thaw) foodstuffs. This paper considers a fixed frequency RF oven, where a matching circuit is used to ensure that the combined impedance of the oven and the food (the load) matches the impedance of the generator and the transmission line. A controller measures the reflected RF signal and adjusts the settings of components in the matching circuit. The system is highly nonlinear and there are significant sources of uncertainty in the model of the process. A variable structure controller is designed and its stability is examined in the presence of uncertainties due to stray components. The switching lines are defined in terms of the real and imaginary parts of the reflected signal, which avoids the need to estimate the states. Conditions are derived for maintaining stability in the region close to the matching point. The performance of the controller is illustrated by results from an implementation on a prototype commercial RF oven.

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