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A highly accelerated power cycling test platform using current source converter for SiC-MOSFET power modules is proposed. The control principles of delta and average junction temperatures are introduced. By using isolated thermal fibers, the junction temperature (Tj) variations can be monitored during the test process without removal of silicone gel. The power module is tested in the conditions of...
Silicon carbide (SiC) power MOSFETs have been becoming a strong alternative to silicon (Si) technology in high-voltage, high-frequency, and high-temperature applications. Despite their growing market share, limited field information is available regarding the aging facts under thermal stress and long term reliability of discrete SiC MOSFETs. In this paper, discrete SiC devices are thermally aged through...
In this paper a charging kinetics of cross-linked polyethylene (XLPE) under electronic beam irradiation in scanning electron microscope (SEM) is quantified by the evaluation of trapped charge. The effect of thermal aging at different temperatures ranged from 80°C to 140°C is highlighted and analyzed. The variation of charging process of XLPE is monitored with measuring the influence current, leading...
In this paper, the degradation at the gate oxide layer of a SiC MOSFET has been studied. The online condition monitoring was achieved by Spread Spectrum Time Domain Reflectometry (SSTDR) for the first time in SiC based devices. An accelerated aging station was built to age the power semiconductor devices in a standardized way, and power cycling test was performed to induce degradation. Finally, the...
In this paper, performance degradation of thermally aged cascode GaN devices is presented in detail. For this purpose, an accelerated aging setup is designed which operates within safe operating area (SOA) to mimic the power cycling in real applications as much as possible. The parametric variations are measured via a curve tracer at certain intervals to find out critical signatures for incipient...
An analysis of the degradation occurred in RF life-tests of n-type MOSFETs operated from pulsed bench for a radar application in S-band is introduced. The analysis comes accompanied with experimental results, which are used to facilitate optimization of the robustness of Power RF MOSFETs. The recorded S-parameters before and after degradation allows the observation of the corresponding changes in...
The paper describes the aging behavior of the NMC/LTO li-ion cell using impedance model of the cell when cycled at different operating conditions. Paper depicts change in impedance with state of charge and cycle life. Both, solution and charge transfer, resistances increase at different stages of battery life. Change is Solution resistance (R1) is impacted by electrolyte decompositions as it changes...
A methodology for lifetime testing of lithium-ion batteries in small SOC intervals is presented. The specific test procedure and level of control is important in producing reliable data. The methodology offers high precision without increasing the test duration. The duration time can be reduced with up to 50%, by ensuring more continuous cycling and by reducing the number of performance tests.
In safety-critical systems, many-processor Systems-on-Chip are being increasingly employed. An example is an imminent collision detection System-on-Chip for cars. Such a system requires zero downtime and a very high reliability despite aging issues under harsh environmental conditions. By monitoring the health status of processor cores and other IPs, and taking appropriate counteractions if required,...
Because of excellent electrical properties, epoxy resin is widely used in packaging and casting power equipment. Moisture and temperature in the environment are inclined to seriously affect the insulation tolerance of epoxy resin. This work focuses on the aging characteristics of epoxy resin in hygrothermal environment. The effect of hygrothermal aging on the properties of epoxy resin was deeply studied...
Light output performance of power LEDs is sensitive to the junction temperature and also changes with the elapsed lifetime of the device. A smart control to achieve constant light output of LED based products would be advantageous in many applications such as streetlighting, resulting e.g. in considerable power savings when forward current is reduced when ambient temperatures are lower. Also, continuous...
This paper reviews factors that influence the aging of distribution transformers, including root causes of transformer failure. Existing and proposed load control methods are then reviewed. A distribution model is introduced to help evaluate potential control methods. Coping with transformer aging is an important challenge in power system. The nature of transformer loads is changing with the integration...
The correlation between degradation-induced changes in two important indicators of mechanical properties, namely elongation at break (EAB) and indenter modulus (IM), is examined for flame-retardant ethylene propylene rubber (FR-EPR), silicone rubber (SiR), flame-retardant crosslinked polyethylene (FR-XLPE), and XLPE. The samples were degraded by heat or concurrently by heat and radiation. In the case...
The failure rate of doubly-fed induction generators (DFIG) for wind turbine generations was relatively higher than that of direct-driven generators, according to statistical data from some wind power industries. The rotor insulation was a relatively weak part of the insulation system for DFIG because it was normally subjected to a PWM impulse voltage during the long-time operation. In this paper,...
Dry-type transformers are quite popular in commercial and industrial applications. The IEEE and IEC standards on dry-type transformer loading provide a significant guideline and recommendation for transformer aging rate calculation. In this study, the fundamental information in these standards are used to develop a real-time dry-type transformer thermal model and evaluate transformer insulation performance...
To examine electrical insulation behavior of cables under severe accident environmental conditions, safety-related low voltage cables used as severe accident management equipment were subjected to two tests that simulated two environments: 1) at 155°C, which is the simulated highest assumed temperature when proper accident management measures are taken, 2) at 200°C, which is the maximum durable temperature...
Ceramic insulator is widely used in Indonesian electrical power distribution system. Based on previous research, it is obtained that silicone rubber coating can improve the performance of ceramic insulator due to better hydrophobicity. This paper presents performance of ceramic insulator with and without silicone rubber coating in a coastal area of Pangandaran. 6 silicone rubber coated and 6 uncoated...
Machines in electric vehicles are driven by switching power electronic devices and undergo variable load cycling. In transient conditions high currents and temperatures develop, forcing the electric motor and particularly the insulation materials to undergo severe multi-stress. Insulation degradation will progressively lead to short-circuits which are harmful for the traction motor, vehicle safety...
Transformer insulation ageing has been extensively studied for past many decades as it is one of the major reasons for transformer failure which causes disturbance to the power system, interruption of power to consumers as well as loss of revenue. The estimation of elapsed life of transformer insulation is done by various methods like IEEE thermal model calculation or diagnostic test results. Though...
α-Fe2O3 nanomaterials with different morphology parameters were prepared by varying growth temperature in the thermal oxidation process. After current aging treatment, emission current density increased from 0.05 mA/cm2 to 5.70 mA/cm2 under applied electrical field of 7.8 MV/m.α-Fe2O3 nanoflakes prepared under 350 °C exhibits low threshold field of 5.1 MV/m. Current aging treatment was carried out...
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