Compact High-Turn-Ratio Transformer Design for Remotely Operated Underwater Vehicles

Kompakt Høj-Vindingsforhold Transformerdesign for Fjernstyret undervandsfartøj

Jensen, Jeppe Vilsøe

4. term

Energy Engineering, Master

2025

2025-05-28

34

This thesis develops and tests a compact transformer for the power converter of a remotely operated underwater vehicle (ROV). The current system from AAL Power Group uses a PREMO transformer with a 30:1 turns ratio (the number of coil turns on the primary versus the secondary). That ratio forces the system to run at 750 V instead of the planned 1000 V, which makes it harder to deliver 2 kW efficiently through a 300 m cable. To overcome this, a custom 40:1 transformer with a center-tapped winding was designed. A semi-planar construction was used because it makes it easier to place many turns on one winding while carrying high current on the other. The design targeted two magnetic side effects that strongly influence a phase-shifted full-bridge (PSFB) converter: leakage inductance on the primary and on the secondary. Leakage inductance is the part of the magnetic field that does not link both windings; adjusting it helps the converter switch and transfer energy as intended. The goal was to increase leakage inductance on the primary side and reduce it on the secondary side compared with the PREMO design. SolidWorks 3D models and COMSOL finite-element simulations guided the geometry and material choices. Some differences between simulated and measured values appeared, mainly due to modeling simplifications and uncertain material data. Even so, the prototype reduced secondary-side leakage inductance by 35% and roughly doubled the primary-side leakage inductance. Key design values were confirmed in laboratory tests; integrating the transformer into the full converter is planned as future work.

Dette speciale udvikler og afprøver en kompakt transformer til strømomformeren i et fjernbetjent undervandsfartøj (ROV). Det nuværende system fra AAL Power Group bruger en PREMO-transformer med et viklingsforhold på 30:1 (forholdet mellem antal vindinger på primær- og sekundærsiden). Det tvinger systemet til at køre ved 750 V i stedet for de planlagte 1000 V og gør det sværere at levere 2 kW effektivt gennem et 300 m langt kabel. For at løse dette blev der designet en kundetilpasset 40:1-transformer med midtudtag. En semiplanar opbygning blev valgt, fordi den gør det lettere at have mange vindinger på den ene side og høj strøm på den anden. Designet fokuserede på to magnetiske bieffekter, som har stor betydning i en faseforskudt fuldbro-omformer (PSFB): lækageinduktans på primær- og sekundærsiden. Lækageinduktans er den del af magnetfeltet, som ikke kobler de to viklinger; ved at justere den kan omformeren skifte og overføre energi som tiltænkt. Målet var at øge lækageinduktansen på primærsiden og reducere den på sekundærsiden i forhold til PREMO-designet. SolidWorks 3D-modeller og COMSOL finite element-simuleringer blev brugt til at styre geometri og materialevalg. Der opstod dog forskelle mellem simulerede og målte værdier, primært på grund af modelsimplificeringer og usikkerhed i materialedata. Alligevel reducerede prototypen sekundærsidens lækageinduktans med 35% og fordoblede primærsidens lækageinduktans. Centrale designværdier blev bekræftet i laboratorietests; integration i den fulde omformer er planlagt som fremtidigt arbejde.

[This apstract has been rewritten with the help of AI based on the project's original abstract]

Transformer ; Comsol ; APG ; Transformerdesign ; Højvindingsforhold ; Planar ; Semi-planar

Download PDF
View record in AAU Student Projects