EPE Association: EPE 2018 - LS2a: Reliability

EPE 2018 - LS2a: Reliability
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 01: Devices, Packaging and System Integration > EPE 2018 - LS2a: Reliability

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   Challenges of SiC MOSFET Power Cycling Methodology
By Fredrik GÖTHNER [View]
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Abstract: This paper investigates the power cycling methodology for reliability testing of SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). Dedicated test benches were designed and built to study this issue. The results indicate that power cycling of SiC MOSFETs is affected by threshold voltage instability. A proposal for reducing the influence of the latter is also given. This is done by adding an additional gate pulse to the device under test, in order to achieve an average bias of zero during one cycle of the power cycling experiment.

   Measurement of the transient thermal impedance of MOSFETs over the sensitivity of the threshold voltage
By Maximilian SCHMID [View]
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Abstract: Transient thermal analysis (TTA) on power MOSFETs using the threshold voltage as sensitivity parameter and the saturation region for component heating is a promising alternative to measure the thermal impedance Zth. Current can be reduced, power losses are fully adjustable and sensitivity is increased compared to established setups using RDSon or the body diode. All three measurement methods differ in several points. The principles and necessary electrical measurement setups will be explained. Also the influence of the different locations and sizes of heat dissipating areas will be discussed on the basis of thermal finite element simulations. To proof the feasibility and to show the advantages of the threshold voltage measurement method 18 MOSFETs were tested. The sensitivity of the threshold voltage was analyzed on stability and value. Afterwards all MOSFETs were TTA tested with a new developed prototype and the results compared to reference measurement on two commercial equipments using the body diode to measure Zth. Transient thermal FE simulations were performed to investigate the influence of the different Layers.

   Reliability and Risk Assessment in a Power Electronic based Power System (PEPS): Using Non-Constant Failure Rates of Converters
By Saeed PEYGHAMI [View]
[Download]

Abstract: In this paper, conventional power system reliability and risk indices are employed to evaluate the reliability of a Power Electronic based Power System (PEPS) utilizing Physics of Failure (PoF) based reliability functions. Mission profile based methods have presented to estimate the failure probability of converters which implies non-constant failure rates for converters during operating period. Hence, a piece-wise solution is proposed to employ the Markov chain approach in order to evaluate the system level reliability of the PEPS with the non-constant failure rates. Furthermore, the impact of power management and thermal sharing on the system level reliability are studied. Numerical analyses and experiments are provided to validate the proposed approaches.

   Very Fast Short Circuit Protection for Gallium-Nitride Power Transistors Based on Printed Circuit Board Integrated Current Sensor
By Javier ACUNA [View]
[Download]

Abstract: Gallium-Nitride power transistors have a limited short-circuit withstand time, which can be as low as 200 ns. Typical short-circuit detection methods such as the desaturation detection method and current based methods present difficulties when they are applied to Gallium Nitride devices. The former requires a blanking time and therefore can detect a short-circuit at a relatively late stage, this method also reacts slowly under high-inductive short circuits. Current based methods require either a special transistor with a current mirror or a special package with a Kelvin connection. This work presents the use of a current sensor integrated into a printed circuit board to perform a very fast short-circuit detection. Two detection methods using the integrated current sensor were implemented, which neither use a blanking time nor require a special transistor package. The functioning under both Hard Switch Fault and Fault Under Load types of short circuit was experimentally tested and a resulting short circuit detection time as low as 30 ns is demonstrated.

EPE 2018 - LS2a: Reliability
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2018 ECCE Europe - Conference > EPE 2018 - Topic 01: Devices, Packaging and System Integration > EPE 2018 - LS2a: Reliability
	[return to parent folder]

	Challenges of SiC MOSFET Power Cycling Methodology By Fredrik GÖTHNER	[View] [Download]
Abstract: This paper investigates the power cycling methodology for reliability testing of SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). Dedicated test benches were designed and built to study this issue. The results indicate that power cycling of SiC MOSFETs is affected by threshold voltage instability. A proposal for reducing the influence of the latter is also given. This is done by adding an additional gate pulse to the device under test, in order to achieve an average bias of zero during one cycle of the power cycling experiment.

	Measurement of the transient thermal impedance of MOSFETs over the sensitivity of the threshold voltage By Maximilian SCHMID	[View] [Download]
Abstract: Transient thermal analysis (TTA) on power MOSFETs using the threshold voltage as sensitivity parameter and the saturation region for component heating is a promising alternative to measure the thermal impedance Zth. Current can be reduced, power losses are fully adjustable and sensitivity is increased compared to established setups using RDSon or the body diode. All three measurement methods differ in several points. The principles and necessary electrical measurement setups will be explained. Also the influence of the different locations and sizes of heat dissipating areas will be discussed on the basis of thermal finite element simulations. To proof the feasibility and to show the advantages of the threshold voltage measurement method 18 MOSFETs were tested. The sensitivity of the threshold voltage was analyzed on stability and value. Afterwards all MOSFETs were TTA tested with a new developed prototype and the results compared to reference measurement on two commercial equipments using the body diode to measure Zth. Transient thermal FE simulations were performed to investigate the influence of the different Layers.

	Reliability and Risk Assessment in a Power Electronic based Power System (PEPS): Using Non-Constant Failure Rates of Converters By Saeed PEYGHAMI	[View] [Download]
Abstract: In this paper, conventional power system reliability and risk indices are employed to evaluate the reliability of a Power Electronic based Power System (PEPS) utilizing Physics of Failure (PoF) based reliability functions. Mission profile based methods have presented to estimate the failure probability of converters which implies non-constant failure rates for converters during operating period. Hence, a piece-wise solution is proposed to employ the Markov chain approach in order to evaluate the system level reliability of the PEPS with the non-constant failure rates. Furthermore, the impact of power management and thermal sharing on the system level reliability are studied. Numerical analyses and experiments are provided to validate the proposed approaches.

	Very Fast Short Circuit Protection for Gallium-Nitride Power Transistors Based on Printed Circuit Board Integrated Current Sensor By Javier ACUNA	[View] [Download]
Abstract: Gallium-Nitride power transistors have a limited short-circuit withstand time, which can be as low as 200 ns. Typical short-circuit detection methods such as the desaturation detection method and current based methods present difficulties when they are applied to Gallium Nitride devices. The former requires a blanking time and therefore can detect a short-circuit at a relatively late stage, this method also reacts slowly under high-inductive short circuits. Current based methods require either a special transistor with a current mirror or a special package with a Kelvin connection. This work presents the use of a current sensor integrated into a printed circuit board to perform a very fast short-circuit detection. Two detection methods using the integrated current sensor were implemented, which neither use a blanking time nor require a special transistor package. The functioning under both Hard Switch Fault and Fault Under Load types of short circuit was experimentally tested and a resulting short circuit detection time as low as 30 ns is demonstrated.