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

Abstract

Supercapacitor assisted surge absorber (SCASA) technique is a unique and commercially useful design approach for surge protector devices. SCASA topology is based on the combination of a coupled inductor which partly acts as a transformer, and a supercapacitor sub-circuit. In developing the first commercial product, the research team had to optimize the selection of the magnetic core, based on empirical approaches and industry price constraints. This paper presents a permeance-based design and analytical approach to SCASA, with the topological details of its first successful implementation. While existing SCASA topology performs satisfactorily, this research elucidates design techniques to improve surge absorption by 60% and reduce load clamping by 10% based on high-performance prototypes developed using High-Flux and X-Flux toroids. The test results presented in this research are validated by experimental work carried out in a high-voltage surge laboratory using Noiseken LSS-6230 lightning surge simulator adhering to IEEE C62.41/IEC 61000-4-5 standards. Surge immunity of SCASA prototypes was evaluated using international test procedures of UL-1449 3rd edition standard.

Magnetic Design Aspects of Coupled-Inductor Topologies for Transient Suppression

“…Contrarily, ECs demonstrate signs of degradation by developing bulging tops, as verified in surge tests (see Figure 4a), leading to physical damage of the devices. More details about supercapacitors' transient behavior and surge dissipation in SCs' RC-circuit loops can be found in [12]. In Section 2, we present an overview of how an SC can be placed in a practical surge protector to provide improved performance.…”

“…The varistor model [27] of V20E275 (Littlefuse, UltraMOV Series) used in the SCASA design predicted that the ON resistances (Var1 and Var2) were between 0.2-1 Ω under transient currents [27,28]. Notably, for transient frequencies, the inductive impedances of two SCASA coupled coils dominated; hence, more the inductive secondary coil (i 2 ) received only 8% of the surge current, while 92% of the transient current flowed into Var1 through the primary (i 1 ) coil [29]. More details about the coupled-inductor current division for both transient and 50 Hz RMS conditions were given in our previous publication.…”

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.…”

“…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.…”

Analytical modelling of high‐frequency losses in toroidal inductors

“…Toroidal inductors, transformers, and current transformers are widely used in industry [1,2]. And toroidal inductors are used in key components of power electronics, such as supercapacitorassisted surge absorbers [3], filters [4], and various types of converters in circuits [5]. Due to the introduction of widebandgap devices into power electronic systems, the frequency in the system increases and the AC losses of the magnetic devices increase dramatically [6,7].…”