Patrick Lagonotte

Thermal modeling of an induction machine through the association of two numerical approaches

The thermal modeling of the machine adopted here results from the association of two methods: a nodal approach that models the diffusion in the structure and a computational fluid dynamics approach that characterizes the convective heat exchanges that operate in the end-bracket cavities . This thermal model is then validated after experimentation carried out on an induction machine equipped with thermal sensors. This enables us to evaluate the thermal behavior of the machine in normal operating mode. In particular, the modeling of the convection heat exchanges in the internal cavities has to be done in detail to reproduce the thermal behavior of the machine accurately.

Reduced Thermal Model of an Induction Machine for Real-Time Thermal Monitoring

An electric machine submitted to dissipations and a too high temperature can generate irreversible damage. A reduced thermal model allows us to monitor the critical points of the machine. The thermal modeling of the machine adopted here results from the association of two methods: a nodal approach which models the diffusion in the structure and a computational fluid dynamics (CFD) approach which characterizes the convective heat exchanges which operate in the end cavities. A methodology of reduction is proposed and applied to the thermal model of a 5.5-kW two-pole induction machine to obtain a reduced four-node model for real-time thermal monitoring.

Coupling control volume modeling in fluid and lumped thermal model - Application to an induction machine

The thermal modeling of the machine adopted here uses the nodal method. For the convective heat exchanges in the end spaces, the results obtained from a computationnal fluid dynamics approach are then translated into an equivalent thermal network. Test on an induction machine allows us to validate its thermal nodal model.

Experimental setup for the measurement of local temperature in electronic component during the steady and transient state

Non-contact optical methods can be used for submicron surface thermal characterization of active semiconductor devices. In this work, an experimental device based on near infra-red radiometric method is presented. This device is breadboard to analyze a thermal behaviour of electronic component in steadied and transient state. The absolute temperature distribution is measured at the micron scale. The obtained results highlight the excellent spatial resolution of the experimental measurement apparatus and its great sensitivity for detection of weak thermal emission variations.

Experimental setup for measuring the local temperature of active electronic components

A novel non-destructive and non-contacting technique for the local temperature measurement of heat spot in electronic component is presented. Highly-sensitive lock-in near infrared (NIR) thermography is used to localize the heat spot induced temperature variations down to 10-1°C at a lateral resolution down to 3 μm. Speedy temperature evolution about 10 microseconds can be followed as using an integral InGaAs PIN photodiode assembled with the matched preamplifier.

From Cauer synthesis to Legendre polynomials — The case of the lossless transmission line

Abstract In this article, we study a simple Time Delay System (TDS), the short-circuited lossless transmission line. By realizing the Cauer synthesis of the input impedance, we can put in evidence a special expression of the impulse response of this system. Furthermore, we illustrate on this example a particular link between the Cauer synthesis of infinite order systems and the Legendre polynomials.