Partial discharges in liquid embedded power electronics: Effects of pressure and liquid nature under negative pulse voltage stress

Abdelmalik, A. A.; Nysveen, Arne; Lundgaard, L.E.

doi:10.1109/tdei.2015.005615

Cited by 5 publications

(4 citation statements)

References 10 publications

(13 reference statements)

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“…Polymers have been used as a nonlinear resistive layer at the metallisation edge of power electronic substrates to reduce electric field enhancement at the triple point interface between copper metallisation, a ceramic substrate, and gel or liquid encapsulation. 2,3 Nanocomposite has been developed from different polymers and nanoparticles and dielectric and partial discharge processes in the processes were studied. Hui et al studied electrochemical treeing processes in nanocomposite from crossed-linked polyethylene and silica nanoparticle.…”

Section: Introductionmentioning

confidence: 99%

Low Dielectric Loss Epoxy Polymer Composite from Periwinkle Shell Microparticles

Abdelmalik¹,

Sadiq²,

Umar³

2020

JPS

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The quest for improved polymeric insulation to achieve a compact and reliable electrical and electronic power equipment design brings about the idea of composite polymeric insulation. Emphasis has been on chemically synthesised metal oxide nanoparticles. This paper presents the dielectric behaviour of epoxy polymer composite with microparticles with an average particle size of about 4.3 μm from the periwinkle shell. The changes in the relative permittivity and dielectric loss of the polymer with the periwinkle shell composite metal oxides at low filler concentrations were studied over a frequency range from 200 Hz to 100 kHz. The results showed that the polymer composite exhibits dielectric characteristics that are quite different when compared with the earlier observed results for polymer micro-composites. Unlike the usual expectations of increasing dielectric loss with increasing filler concentration in polymer micro-composites, the dielectric response of the epoxy-shell microparticle powder composite displayed a decrease in the dielectric loss with micro-filler concentration. The 1 wt% periwinkle shell microparticle epoxy composite has a dielectric loss lower than that of 0.5 wt% Al 2 O 3 nanoparticle epoxy composite. This suggests that the waste periwinkle shell can serve as a cheap resource to produce low-cost polymer composite with improved electrical insulation properties.

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Section: Introductionmentioning

confidence: 99%

Low Dielectric Loss Epoxy Polymer Composite from Periwinkle Shell Microparticles

Abdelmalik¹,

Sadiq²,

Umar³

2020

JPS

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“…Our previous work on this topic was connected to short-term and long-term experiments for two critical high field areas, namely substrate trenches and chip edges, and we wanted to find new feasible material candidates and material combinations, i.e., liquid/solid insulation. 10,11 The short-term experiment examined the integrity of some liquid samples (Nytro 10XN, Midel 7131 and Galden HT220) as an encapsulation material for the IGBT module and it was concluded that any of the liquids could be used for encapsulation but Galden has a better performance. 10 In non-stagnant liquid insulation, impurities can be dragged towards the high field triple-point region by dielectrophoretic forces.…”

Section: Introductionmentioning

confidence: 99%

“…10,11 The short-term experiment examined the integrity of some liquid samples (Nytro 10XN, Midel 7131 and Galden HT220) as an encapsulation material for the IGBT module and it was concluded that any of the liquids could be used for encapsulation but Galden has a better performance. 10 In non-stagnant liquid insulation, impurities can be dragged towards the high field triple-point region by dielectrophoretic forces. Particles may lead to further enhancement of the field initiating PDs.…”

Section: Introductionmentioning

confidence: 99%

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Electric field enhancement control in active junction of IGBT power module

Abdelmalik¹,

Liland²

2020

JPS

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Dielectric liquids are incompressible, able to fill voids and have selfhealing effect and hence are being considered as alternative encapsulation materials to establish power electronics at ambient high pressure at subsea conditions. In a long-term endurance test, insulated-gate bipolar transistor (IGBT) chips subjected to 6.5 kV DC stress in dielectric oil environment was reported to have failed after less than one week in operation. A critical look at the failed objects revealed contamination fibres at the surface and around the high field regions. This paper presents the numerical simulation of field distribution around a conducting fibre at the surface of the IGBT chip. It also evaluates the influence of the nature of the encapsulation material on the integrity of power electronic modules using a long-term experiment at a medium elevated temperature for high and low relative humidity operated close to service load using IGBT relevant chips. Finite element method (FEM) calculations show how the high field region can be shielded from impurities that can easily trigger partial discharge (PD) and breakdown. The simulation suggests that coating the surface of the module with a thin polymer layer with a thickness of 20 μm or more could be sufficient to improve the reliability of the encapsulation system. Additional polymer coat with thickness 27 μm on the chip made the system survive without failure for 67 weeks under test and dry operating condition. Meanwhile, thick coating such as silicone gel protected the object longer under higher relative humidity.

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Influence of sinusoidal and square voltages on partial discharge inception in geometries with point‐like termination

Abdelmalik

2018

High Voltage

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High-voltage equipment involves both electrical and electronic components. In electrical power network, which consists of rotating machine, power transformers and transmission lines, field enhancement at critical regions can lead to local breakdown [partial discharges (PD)]. The continuous occurrence of PDs can lead to complete breakdown. While in large power equipment sharp edges can be avoided, this is not the case in power converter due to the miniature nature of the semiconductor device. Sharp edges can also be present in any power equipment in the shape of conducting particles, either stuck at a barrier or freely moving in the bulk oil. This creates high-field regions, prone to PD activities. Different power equipment operates at different voltages such as AC, DC, square voltage, pulse voltage, fast-rise transient voltage etc. This study presents the influence of sinusoidal voltage, slow-and fast-rise square voltage on PDs in two different geometries using optical PD measurement technique. Fast-rise square voltage has the lowest PD inception voltage while the sinusoidal voltage has the highest. This is may be due to the influence of homo-and hetero-charges. Fast-rise square voltage displayed higher PD magnitude at inception which may be connected to the rise time of the voltage.

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Partial discharges in liquid embedded power electronics: Effects of pressure and liquid nature under negative pulse voltage stress

Cited by 5 publications

References 10 publications

Low Dielectric Loss Epoxy Polymer Composite from Periwinkle Shell Microparticles

Low Dielectric Loss Epoxy Polymer Composite from Periwinkle Shell Microparticles

Electric field enhancement control in active junction of IGBT power module

Influence of sinusoidal and square voltages on partial discharge inception in geometries with point‐like termination

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