Reduced Leakage Inductance and Higher Efficiency
Customer challenge
The customer's existing transformer, from a competitor, had three issues:
- it lost too much energy to leakage inductance
- ran at low efficiency, and got too hot during use.
The customer needed a transformer that performed significantly better on all three fronts; not just a small improvement, but a real step up.
Climate & Energy Technology
Key challenges
High leakage inductance — energy lost instead of transferred efficiently
- Low efficiency — more power going in than usefully coming out
- Poor temperature management — the transformer ran too hot
- Demanding targets — a 43% reduction in leakage inductance, efficiency of at least 85%, and a maximum temperature of 120°C at 60°C ambient
- Large improvement margin needed — the new design had to clearly outperform the existing (competitor) transformer, not just match it
Our Solution
We addressed the challenge with two design choices:
- Winding count — we chose the right number of windings to reduce leakage inductance
- Litz wire instead of solid wire — using multiple thin, insulated strands instead of a single solid wire cuts losses and helps the transformer run cooler and more efficiently
It was the combination of solid transformer theory and hands-on engineering experience, which allowed us to reach the target performance using materials already available in-house.
ISE MAGNETICS Engineering department
From concept to realization
The right balance of primary and secondary windings, combined with the right litz wire construction, is what turned the design from a concept into a working transformer that met every target.
Results
- Efficiency above 90% — a strong result for a flyback transformer
- Better thermal performance: operating at 106°C << 120°C
- Lower losses, since higher efficiency means less energy is wasted
- Longer lifespan: the transformer runs well below the temperature rating of its insulation materials (106°C versus a 130°C rating)
- Better reliability, as a direct result of that longer lifespan
- Compact dimensions, in line with the customer's requirements
- Lower EMI (electromagnetic interference), thanks to the reduced leakage inductance
- Higher power density, made possible by the higher efficiency
- The customer is very satisfied with the result
Measurement Data
- Efficiency improvement: 90.3% versus 84.6% for the previous transformer
- Temperature reduction: from 120°C down to 68°C — a 52°C improvement
- Lower core and copper losses: core temperature down from 79°C to 55°C; copper temperature down from 120°C to 68°C
Other cases
Every application requires a different balance between force, precision, size, and integration. Explore how we solved similar challenges for other high-tech applications.
