1K107 Nanocrystalline Alloy Ring Core for Efficient Transformers

 

Nanocrystalline core loss increases with frequency, primarily due to eddy currents and hysteresis. While nanocrystalline materials have very low core losses at lower frequencies, the loss components increase as frequency rises, especially above100 kHz. This relationship is a critical design consideration for power electronics applications, and manufacturers have developed specialized high-frequency (HF) grades of nanocrystalline cores to improve performance.

 

 

 

 

Factors influencing Nanocrystalline Core loss vs. frequency

 

Eddy current losses:

These are the most significant loss component at high frequencies and are proportional to the square of the frequency . Although nanocrystalline materials have a very fine grain structure that minimizes eddy currents at lower frequencies, they become dominant as frequency increases.

 

Hysteresis losses:

These losses are also dependent on frequency and flux density, and they contribute to the total core loss.

 

Excess losses:

These are a component of core loss that arises from the unique microstructure of the material and are also influenced by frequency.

 

Material properties:

The electrical conductivity of the nanocrystalline material itself plays a crucial role, as a higher conductivity leads to greater eddy current losses at high frequencies.

 

Core design:

The physical structure of the core, including its thickness and insulation, affects how well it can withstand high-frequency losses.

 

 

Nanocrystalline Alloy Core Performance at different frequencies

 

Low to medium frequencies (10−100 kHz):

Nanocrystalline cores exhibit superior performance, with some of the lowest core losses of any magnetic materials in this range, providing excellent efficiency for applications like power converters.

 

High frequencies (above 100 kHz):

Eddy current losses increase exponentially, causing a rapid rise in total core loss. In some cases, nanocrystalline cores may have higher losses than specialized ferrite materials in this very high-frequency range.

 

 

Nanocrystalline Alloy Ring Core Design implications

 

High-frequency grades:

To mitigate the effects of high frequencies, manufacturers offer specialized high-frequency (HF) nanocrystalline materials with lower core losses in the target operating range.

 

Performance factors:

Material selection for transformers often involves using a "performance factor" which is the product of AC flux density and frequency at a given power loss.

 

Thermal management:

The increase in core loss at high frequencies generates more heat, which can lead to reduced efficiency and requires careful thermal management in the overall design.

 

Nanocrystalline toroidal Core specification

Magnetic core size(mm)			Protective box size(mm)			Effective cross-sectional area Ae(mm2)		Magnetic path length Ie(mm)		Maximum DC overcurrent class (A)
id	od	ht	ID	OD	HT
14	19	6.5	12	22	8	11.86		51.81		20
14	20	10	12	22.3	11.4	29.68		52.29		40
16	21	10	15	24	12.3	24.85		57.41		60
16	23	8	15	24	9.7	20.44		61.23		60
16	23	10	15	24	12.3	34.62		59.92		60
17	22	10	15.3	24.4	12.3	24.86		60.59		60
17	21	8	15.3	24	9.7	25.56		60.67		60
17	23	8	15.3	24.4	9.7	26.89		61.34		60
18	23	10	16.4	24.4	12.3	29.78		60.38		70
18	24	9	16.4	25	11.2	34.78		60.89		70
18	25	10	16.4	25.9	12.3	37.97		64.56		70
19	24	9	17.3	25	11.2	40.39		65.32		80
19	25	10	17.3	26	12.3	39.42		62.31		80
19	26	10	17.3	27.3	12.3	48.32		69.56		80
20	25	10	18.5	26.3	12.3	39.29		70.32		90
20	28	10	18.5	29	12.3	45.76		73.88		90
20	32	10	18.5	32.3	12.3	58.91		78.75		90
21	29	10	18.2	31.3	12.3	39.65		77.19		100
21	26	8	18.3	27.4	9.7	46.54		78.32		100
21	28	10	18.3	30	12.3	50.39		77.45		100
22	28	10	20.5	30	12.3	49.32		79.89		120
22	32	10	20.5	33.4	12.3	43.58		73.43		120
23	32	10	21.3	33.4	12.3	44.56		74.56		120