Development of a High Permeability Cored Transintegumental Power Transformer

Aj, Helmicki; Dm, Melvin; Ht, Henderson; Nebrigić, D.; Venkat, Ramanan Sridaran; Dl, Glos

doi:10.1097/00002480-199609000-00063

Cited by 4 publications

(2 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Separate papers address further engineering and design analysis issues for the transformers (21) and their control systems (22).…”

Section: Methodsmentioning

confidence: 99%

“…As a result, a series resonant converter configuration was selected for the DC/AC converter, and a Schottky bridge rectifier configuration was chosen for the AC/DC converter. The design details and full specifications are included in a paper accepted for publication (22). The converters tuned to each of the transformer configurations with a purely resistive load of 5.8 R, and a fixed gap distance of 3 mm for Type A were designed, fabricated, and bench tested (90.2 kHz for Type A and 14.7 kHz for Type B).…”

Section: Power Supply and Monitoring Systemmentioning

confidence: 99%

See 1 more Smart Citation

In Vivo Comparison of Two Enteric‐Pouch Power Transformers for Circulatory Support

Dl²,

Nebrigić

et al. 1997

Artificial Organs

Self Cite

View full text Add to dashboard Cite

A defunctionalized ileal pouch is thin-walled (1-2 mm), well perfused (blood flow, 0.3-1.0 ml/g/min), and tactile-insensitive. If fixed within the abdominal wall and provided with a miniature stoma for primary wire entry, the heat dissipating capacity and achievable geometries could facilitate small efficient intra-to extracorporeal power transformers with virtually complete magnetic flux containment. Two transformers (A, weighing 102 gm with dual ferrite cores, intraluminal primary and extraluminal secondary each with 10 turns on its own crescentic ferrite core, 90 kHz, coupling coefficient k = 0.90-0.96; and B, 68 gm, a single flexible torroidal magnetic metallic tape core with attached 11 turn primary and free 14 turn serosal secondary, 14.7 kHz, k = 0.99) met the electrical and anatomic requirements. Each was implanted (minilaparotomy, coil-pouch fixation within abdominal musculature) in 4 dogs for 14-21 days to test the operative feasibility, electrical function, warming, and flux containment. For canine testing, wires were tunneled to a chewing-inaccessible site. Neither tissue necrosis, infection, provokable interference from contiguous metal, nor coil displacement were observed; secretions were retained in Group A pouches only. The mean power transmissions for the transformers were A: 24.90 & 1.50 W and B: 24.92 & 0.89 W, after operation for 7 days or more. The mean efficiencies were A: 75.6 * 0.1% total DCIDC, 96.2% coils and B: 80.4 + 0.1% total DC/DC, 96.2% coils. The peak skin surface magnetic fluxes for transformers A and B, both trivial at 1.7 and 1.2 G, respectively, were similar. Warming was 0.62 k 0.30"C in Group A and 0.73 f 0.19"C in Group B. The probability values were p < 0.5 (NS) for DC/DC efficiency and p > 0.10 (NS), for A versus B in all other areas of comparison. Observations for both were encouraging. Transformer B, with less mass, lower frequency, higher efficiency, and intrinsic invulnerability to displacement, was selected for longer term evaluation.

show abstract

“…Separate papers address further engineering and design analysis issues for the transformers (21) and their control systems (22).…”

Section: Methodsmentioning

confidence: 99%

Section: Power Supply and Monitoring Systemmentioning

confidence: 99%

In Vivo Comparison of Two Enteric‐Pouch Power Transformers for Circulatory Support

Dl²,

Nebrigić

et al. 1997

Artificial Organs

Self Cite

View full text Add to dashboard Cite

show abstract

Control of drug release from capsules using high frequency energy transmission systems

Gröning

Bensmann

Müller

2008

International Journal of Pharmaceutics

View full text Add to dashboard Cite

Miniature Circulatory Support Power Transformer

Melvin

Helmicki²,

Glos³

2000

ASAIO Journal

View full text Add to dashboard Cite

Direct power delivery to intracorporeal circulatory support devices risks infection. Electrical transformers spanning the integument (skin or mucosa) have long been attractive means of circumventing this risk. Yet all existing skin surface transformers leak substantial magnetic flux, with an intrinsic risk of battery draining cross-coupling by any nearby conductor, requiring strict control of surroundings. In a progression of designs, we have used the walls of a small pouch, surgically formed from ileum, rather than skin, as a barrier. Previously, we reported a torroidal design with complete magnetic circuits, having zero flux leakage and unmatched heat dissipation in a 2 week canine trial. This work was in three parts: (1) Devices were placed in eight dogs for 9-12 weeks to document performance of the existing design. (2) Based on these results, the device was further miniaturized. Iterative computational modeling was applied to material selection and design. Simultaneously, practical techniques for surgically constructing tiny accommodating ileal pouches were explored in cadavers, by using polymer "mock-ups" of potential designs. (3) The final design was tested by acute implantation in a live 52 kg goat and by in vitro testing of electrical transfer function. IN VIVO TRIALS: The earlier design demonstrated 97.2% AC/AC and 84.2% DC/DC efficiency with contiguous tissue warming of 0.1 degrees C. DESIGN AND PERFORMANCE: A transformer with a Square Permalloy torroidal core (6 cm3, 23 grams, both coils eight turns) was designed, by using human cadaver trials to optimize geometry. Input and output were 6 V, 12W at 9.2 kHz with AC-AC efficiency 96%. OPERATIVE PLACEMENT TRIAL: The primary coil easily fit into an isolated, vascularized, but otherwise disconnected "blind" ileal pouch < 2 cm long with a slender extension to a miniature stoma. With secondary turns, the pouch and transformer fit easily into the abdominal wall. This tiny system seems compatible with near "forgettable" power delivery allowing unprecedented freedom of environment and activity in circulatory support dependent people.

show abstract

Development of a High Permeability Cored Transintegumental Power Transformer

Cited by 4 publications

References 0 publications

In Vivo Comparison of Two Enteric‐Pouch Power Transformers for Circulatory Support

In Vivo Comparison of Two Enteric‐Pouch Power Transformers for Circulatory Support

Control of drug release from capsules using high frequency energy transmission systems

Miniature Circulatory Support Power Transformer

Contact Info

Product

Resources

About