This paper proposes a synthesis of different electrical methods used to estimate the temperature of power semiconductor devices. The following measurement methods are introduced: the voltage under low current levels, the threshold voltage, the voltage under high current levels, the gate-emitter voltage, the saturation current and the switching times. All these methods are then compared in terms of sensitivity, linearity, accuracy, genericity, calibration needs and possibility of characterizing the thermal impedance or the temperature during the operation of the converter. The measurement of thermo-sensitive parameters of wide band gap semi conductors is also discussed.

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The measurement of the junction temperature with thermo-sensitive electrical parameters (TSEPs) is largely used by electrical engineers or researchers but the obtained temperature value is generally not verified by any referential information of the actual chip temperature distribution. In this paper, we propose to use infrared (IR) measurements in order to evaluate the relevance of three commonly used TSEPs with IGBT chips: the saturation voltage under a low current, the gate-emitter voltage and the saturation current. The IR measurements are presented in details with an estimation of the emissivity of the black paint deposited on the power module. The temperatures obtained with IR measurements and with the different TSEPs are then compared in two cases: the use of only one chip and the use of two paralleled chips.

Power conversion systems are dependent on the performance and reliability of static converters. However, they are subject to frequent functional and environmental strains, which can induce failures. The anticipation of these failures is difficult but important so the operation of a system can be halted before a breakdown occurs. In the case of photovoltaic (PV) power plants, the system can be simplified into two distinct blocks: the solar panels/modules and the power inverter. A breakdown in either of these blocks can cause significant downtime in the system. Nevertheless, multiple solar module failures can often be tolerated and not lead to a total breakdown of the entire array, whereas a single component failure in the inverter can lead to a collapse of the entire system. Furthermore, solar panel/module manufacturers often offer warranties of up to 20 years, while warranties for inverters rarely reach the ten-year mark [1]. As such, the overall cost of a PV inverter can increase by a factor of two or three if it undergoes one or two failures during the life of the system. Although the market competition between PV inverter manufacturers has traditionally focused on the efficiency of their product, a failure that induces a downtime of just a few days can easily negate the yield attained through a 1% efficiency improvement. Oversizing the inverter or introducing redundancy into the inverter system is one option to improve reliability; however, often, this is not economical

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The temperature of a power semiconductor device is important for both its optimal operation and reliability. If the temperature is known during the operation of a converter, it can be used to monitor the health of power modules: a measurement of aging, scheduling of maintenance, or even implementation of active thermal control to reduce losses and increase lifetime can be performed given an accurate knowledge of temperature. Temperature measurements via thermo-sensitive electrical parameters (TSEP) are one way to carry out immediate temperature readings on fully packaged devices. However, successful implementation of these techniques during the actual operation of a device has not yet been achieved. This paper provides an overview of literature where the usage of TSEPs has been hypothesised or realised in realistic power electronic converter setups. Barriers and limitations preventing wider scale implementation of these methods are discussed. Their potential use in the aforementioned goals in condition monitoring and active thermal control is also described.

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