Philippe Masson

A compact transient electrothermal model for integrated power systems: Automotive application

The paper is about a so-called ”diffusive representation”, a new modeling dynamic systems method and its application to efficient transient thermal modeling of multichip power module taking into account thermal coupling effects. Compact thermal models are required for many analyses during the design of power systems. Generally a RC-ladder model is used and analytical expressions enable to quantify R and C values. Unfortunately the trade-off between complexity, convergence and accuracy is hard to settle. Diffusive approximation of the heat law equation offers an alternative representation. The compact thermal model is a state space model. Parameters identification procedures are given and are validated. The method is applied on an inverter leg, a 400A MOSFET power module manufactured by VALEO for starter-alternator system. Electrothermal measurements have been achieved to develop an electrical model with thermo-sensitive parameters of the MOSFET dies. Electro-thermal measurements and 3D Finite Element thermal simulations have been performed for validations. A compact diffusive model comes as a state space model and may be easily implemented in a ”circuit” simulator.

Sensorless control of a wound rotor synchronous belt-driven starter-alternator

The main purpose of this work is to achieve a low-cost sensorless drive for wound rotor synchronous belt-driven starter-alternator (StARS). These electrical machines manufactured by automotive suppliers are intended to equip light cars. Classically, the self-commutation operation of the StARS is controlled by electromechanical position sensors. However, these last suffer from complex wiring and reliability issues. To overcome these problems, authors propose a sensorless control method which deals with initial rotor position detection and motor parameter identification at stand-still. A back-emfs estimation method suitable for non-zero speeds is presented as well as a DSP implementation of the suggested sensorless technique. Experimental results verify the good operation of the proposed solution.

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.