Optimization of Supercapacitor Assisted Surge Absorber (SCASA) Technique: A New Approach to Improve Surge Endurance Using Air-Gapped Ferrite Cores

Abstract

SCASA is a patented technique commercialized as a surge protector device (SPD) that adheres to UL-1449 test standards. Apart from the novel use of supercapacitors, SCASA design incorporates a coupled-inductor wound to a specially selected magnetic material of powdered-iron. In this study, we investigate the limitations of the present design under transient operation and elucidate ways to eliminate them with the use of air-gapped ferrite cores. In modelling the operation under 50 Hz AC and transient conditions, a permeance-based approach is used; in addition, non-ideal characteristics of the transformer core are emphasized and discussed with empirical validations. The experimental work was facilitated using a lightning surge simulator coupled with the 230 V AC utility mains; combinational surge-waveforms (6 kV/3 kA) defined by IEEE C62.41 standards were continuously injected into SPD prototypes during destructive testing. Such procedures substantiate the overall surge-endurance capabilities of the different core types under testing. With regard to optimizations, we validated a 95% depletion of a negative-surge effect that would otherwise pass to the load-end, and another 13–16% reduction of the clamping voltage verified the effectiveness of the methods undertaken. In conclusion, SCASA prototypes that utilized air-gapped cores revealed a greater surge endurance with improved load-end characteristics.

Permeance Based Design and Analysis of Supercapacitor Assisted Surge Absorber for Magnetic Component Selection

“…To understand the surge absorption by the magnetic core, operation of the coupled-inductor design under transient conditions was considered. In a separate research given by [19], it was proven that an indication about the energy storage capability of SCASA coupled-inductor windings is given by the difference (v s − v p ) between secondary induced voltage v s and primary induced voltage v p . This effect is due to the design configuration of SCASA topology in which secondary coil possesses a much larger self-inductance L s (∼60 µH) than the primary self-inductance L p (∼3.8µH).…”

Supercapacitor assisted surge absorber technique: high performance transient surge protectors for consumer electronics

“…Power electronics research group at the University of Waikato, launched a PhD thesis completed by the first author [10]- [14], based on the preliminary investigations which lead to the first patent [8]. As per detailed research published in [12]- [16], a uniquely new circuit topology as per Figure 10(d) was successfully developed by the team at Waikato. This was based on a step by step analysis of Figures 10(a) to 10(c).…”

“…To provide a complete analysis with design calculations leading to a testable prototype of the SCASA is beyond the scope of this paper. These details are available in [1,[12][13][14][15][16]. A summary useful for a designer is given below, based on the preliminary prototypes build and the first commercial product developed which will be discussed later.…”

“…In developing this new topology, the coupled inductor acts as a loosely coupled transformer, when the MOV enters into conducting stage. Design of this coupled inductor was based on a permeance (inductance per square turns) based approach, as detailed in [10], [16]- [19]. Without a detailed discussion, at the first stage of research and development, the research team had a concluding result that powdered alloys work effectively in the SCASA design while ferrite cores were not effective.…”

“…But, in the gapped form (single-gapped or double-gapped), ferrites perform satisfactorily. More investigations about air-gapped ferrites and other suitable magnetic materials are found in [20].…”