Avaliação da influência da temperatura de junção no desempenho de um módulo IGBT empregando sensores a fibra ótica

Abstract

This study aims to evaluate the temperature influence on power losses of an IGBT module (Insulated Gate Bipolar Transistor), monitoring the temperature through direct measurement, using optical sensors. The direct monitoring of temperature is accomplished by means of optical sensors based on fiber Bragg grating installed inside the module, positioned on the semiconductor wafer, which forms the IGBT structure. For the experimental analysis to be performed under controlled temperature conditions, a digital temperature control system based on a Peltier effect thermoelectric module was developed, which can regulate the temperature in a range between -16 °C to 150 °C, with an percentage error of 0.1%. The drive of the IGBT module is done by a test circuit that can vary the device electrical parameters, such as pulse width, voltage and load current. A digital oscilloscope, providing verification of device performance during the switching and conduction of electrical current, obtains the waveforms that describe the IGBT behavior. The drive of the IGBT under controlled temperature allows checking the temperature ranges that have significant influence on the device power losses. The use of optical sensor provided to identify the heat generated on the device junction due to the power losses. The direct measurement of junction temperature also contributed to the development of a simple technique with great precision to obtain the thermal parameters of the IGBT structure. The parameters obtained were the basis for developing a precise thermal model that faithfully simulates the device thermal behavior, where the maximum percentage error is 0.3%, approximately. The model facilitates the analysis of small variations in temperature, lower than 0.01 °C, where measurement by the sensor becomes more complicated. The association of the temperature influence analysis on the IGBT performance with monitoring and simulation of generated heat on the structure during device operation, can contribute to the research on design of novel power semiconductor devices.