Importance of Leakage Magnetic Field and Fringing Flux in Surge Protector Design

Thotabaddadurage, Sadeeshvara Silva; Kularatna, Nihal; Steyn-Ross, D. Alistair

doi:10.1109/tia.2022.3208920

Cited by 2 publications

(2 citation statements)

References 12 publications

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“…Contrary to highpermeability (µ r = 10,000) ferrite cores (Figure 6b) [17], powdered materials are fabricated with distributed air-gaps, resulting a permeability reduction. Notably, this air-gapping effect in powdered cores provides a greater energy storage capability to the core than that of pure ferrites [18]. To investigate this further, we designed tests to observe the magnetic operation of the SCASA coupled-transformer coils (more details found in Section 3.2).…”

Section: Powdered-iron Vs Ferrite Magnetic Coresmentioning

confidence: 99%

Magnetic Design Aspects of Coupled-Inductor Topologies for Transient Suppression

2023

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Based on the discovery of the surge absorption capability of supercapacitors, a transient protector named supercapacitor-assisted surge absorber (SCASA) was designed and implemented in a commercial device. Despite its simplicity, the circuit topology consisted of a coupled inductor wound around a specially selected magnetic core. This paper elucidates the design aspects of SCASA coupled-inductor topologies with a special focus on the magnetic action of core windings during transient propagation. The non-ideal operation of the SCASA transformer was studied based on a semi-empirical approach with predictions made by using magnetizing and leakage permeances. The toroidal flux distribution through the transformer was also determined for a 6 kV/3 kA combinational surge, and these findings were validated by using a lightning surge simulator. In predicting the possible effects of magnetic saturation, the hysteresis properties of different powdered-iron and ferrite core types were considered to select the optimal design for surge absorption. The test results presented in this research revealed that X-Flux powdered-iron toroid and air-gapped EER ferrite yielded exceptional performance with ∼10% and ∼20% lower load–voltage clamping compared to that of the existing Kool μu design. These prototypes further demonstrated a remarkable surge endurance, withstanding over 250 consecutive transients. This paper also covers details of three-winding design optimizations of SCASA and LTSpice simulations under the IEC 61000/IEEE C62.45 standard transient conditions.

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Section: Powdered-iron Vs Ferrite Magnetic Coresmentioning

confidence: 99%

Magnetic Design Aspects of Coupled-Inductor Topologies for Transient Suppression

2023

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“…In addition to the original STS circuit developed using a Kool µu 0077071A7 [41] core (see Figure 7b,d), several other advancements have been accomplished using high-flux (see Figure 7e) and X flux (see Figure 7f) powdered iron magnetic materials [42]. Furthermore, in recent research given in [43], we have further improved the surge endurance and loadclamping properties of the STS by adopting an air-gapped EER ferrite core (see Figure 7g) in the coupled inductor. A comparison of the magnetic characteristics of these core samples used for prototype advancements can be found in [44].…”

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confidence: 99%

Laplace Transform-Based Modelling, Surge Energy Distribution, and Experimental Validation of a Supercapacitor Transient Suppressor

Silva Thotabaddadurage

2023

Technologies

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The discovery of the transient-surge-withstanding capability of electrochemical dual-layer capacitors (EDLCs) led to the development of a unique, commercially beneficial circuit topology known as a supercapacitor transient suppressor (STS). Despite its low component count, the new design consists of a transient-absorbing magnetic core which takes the form of a coupled inductor placed between the AC-main- and load-side varistors. With an introduction to the structural features of metal oxide varistors (MOVs), gas tubes, thyristors, and EDLCs, this research presents a frequency (S)-domain analysis of an STS circuit to accurately model the surge propagation through its coupled inductor. Transient energy distribution trends among STS components are estimated in this paper, with an emphasis on peak energies absorbed and dissipated by the various inductive, capacitive, and resistive circuit elements. Moreover, this study reveals STS transient-mode test waveforms validated by a standard lightning surge simulator with supporting simulation plots based on LTSpice numerical techniques. Both experimental and simulation results are consistent, with the analytical findings showing 90% of the peak transient propagating through the primary coil, whereas only 10% is shared into the secondary coil of the coupled inductor. In addition, it is proven that the two STS MOVs dissipate over 50% of the transient energy for a standard 6 kV/3 kA combinational surge, while the magnetic core absorbs over 20% of the energy. All test procedures conducted during this research adhere to IEEE C62.41/IEC 61000-4-5 standards.

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Importance of Leakage Magnetic Field and Fringing Flux in Surge Protector Design

Cited by 2 publications

References 12 publications

Magnetic Design Aspects of Coupled-Inductor Topologies for Transient Suppression

Magnetic Design Aspects of Coupled-Inductor Topologies for Transient Suppression

Laplace Transform-Based Modelling, Surge Energy Distribution, and Experimental Validation of a Supercapacitor Transient Suppressor

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