US 2026/0110756 A1Published application

Method and system for calculating magnetic flux density distribution of nanocrystalline core, medium, and device

AssigneeXi' An Jiaotong University

InventorsLingyu ZHU, Zhanlei LIU, Yongliang DANG, Shengchang JI

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Abstract

Disclosed are a method and system for calculating a magnetic flux density distribution in a nanocrystalline high-frequency transformer core under a load condition, a medium, and a device. In the method, a magnetic flux density under a load condition is decomposed into a magnetic flux density under an open-circuit condition and a magnetic flux density under a short-circuit condition that are subjected to superposition. The magnetic flux density in the nanocrystalline core under an open-circuit condition and the magnetic flux density in the nanocrystalline core under a short-circuit condition are merely simulated through frequency domain finite element simulation, and then subjected to superposition calculation to obtain the magnetic flux density distribution in the nanocrystalline core under a load condition. Time domain finite element simulation calculation is omitted, and therefore simulation calculation time is greatly shortened, and calculation efficiency is improved.

Claims18

Dependent claims

A method for calculating a magnetic flux density distribution in a nanocrystalline high-frequency transformer core under a load condition, comprising:

under a load condition, an average magnetic flux density passing through a section S in the nanocrystalline high-frequency transformer core by adopting an equivalent magnetization voltage, wherein a magnetic flux □load in the nanocrystalline core under a load condition is equal to a sum of a main flux □main under an open-circuit condition and a leakage flux □leakage under a short-circuit condition, that is, φload=φmain+φleakage, and an EMVum,load of a particular section S of the nanocrystalline core under a load condition is equal to a sum of an EMVum,open of the section under an open-circuit condition and an EMVum,short of the section under a short-circuit condition, that is,
u
m
,
load
=
u
m
,
open
+
u
m
,
short
;
expressing, based on Fourier superposition principle, an open circuit voltage uopen and a short circuit voltage ushort as follows:
u
open
=
∑
i
=
1
n
u
open
,
sin
,
n
,
u
short
=
∑
i
=
1
n
u
short
,
sin
,
n
,
in the formula, uopen,sin,n denotes an nth harmonic component of the open circuit voltage, and ushort,sin,n denotes an nth harmonic component of the short circuit voltage, and an EMVum,open,n under nth harmonic excitation of the open circuit voltage and an EMVum,short,n under nth harmonic excitation of the short circuit voltage are expressed as follows:
um,open,n=k1uopen,sin,n, um,short,n=k2ushort,sin,n in the formula, k1 denotes a coefficient related to a main flux distribution in the core under open-circuit sinusoidal excitation, and k2 denotes a coefficient related to a leakage flux distribution in the core under short-circuit sinusoidal excitation, and an EMV under an open-circuit condition and an EMV under a short-circuit condition are expressed as follows:
u
m
,
open
=
∑
i
=
1
n
u
m
,
open
,
n
=
k
1
⁢
∑
i
=
1
n
u
open
,
sin
,
n
=
k
1
⁢
u
open
,
u
m
,
short
=
∑
i
=
1
n
u
m
,
short
,
n
=
k
2
⁢
∑
i
=
1
n
u
short
,
sin
,
n
=
k
2
⁢
u
short
,
and the EMV of the section S in the nanocrystalline core under a load condition is expressed as follows:
u
m
,
load
=
k
1
⁢
u
open
+
k
2
⁢
u
short
;
and expressing, through an integral operation, the average magnetic flux density in the section S in the core as follows:
B
ave
(
t
)
=
1
S
⁢
∫
u
m
,
load
⁢
dt
=
1
S
⁢
∫
(
k
1
⁢
u
open
+
k
2
⁢
u
short
)
⁢
dt
.

178 more elements

A system for calculating a magnetic flux density distribution in a nanocrystalline high-frequency transformer core under a load condition, comprising:

a load measuring unit configured to characterize, under a load condition, an average magnetic flux density passing through a section S in the nanocrystalline high-frequency transformer core by adopting an equivalent magnetization voltage, wherein a magnetic flux □load in the nanocrystalline core under a load condition is equal to a sum of a main flux □main under an open-circuit condition and a leakage flux □leakage under a short-circuit condition, that is, φload=φmain+φleakage, and an EMVum,load of a particular section S of the nanocrystalline core under a load condition is equal to a sum of an EMVum,open of the section under an open-circuit condition and an EMVum,short of the section under a short-circuit condition, that is, um,load=um,open+um,short;
a voltage calculating unit configured to calculate, based on Fourier superposition principle, an open circuit voltage uopen and a short circuit voltage ushort, wherein the open circuit voltage uopen and the short circuit voltage ushort are expressed as follows:
u
open
=
∑
i
=
1
n
u
open
,
sin
,
n
,
u
short
=
∑
i
=
1
n
u
short
,
sin
,
n
,
in the formula, uopen,sin,n denotes an nth harmonic component of the open circuit voltage, and ushort,sin,n denotes an nth harmonic component of the short circuit voltage, and an EMVum,open,n under nth harmonic excitation of the open circuit voltage and an EMVum,short,n under nth harmonic excitation of the short circuit voltage are expressed as follows:
um,open,n=k1uopen,sin,n, um,short,n=k2ushort,sin,n, in the formula, k1 denotes a coefficient related to a main flux distribution in the core under open-circuit sinusoidal excitation, and k2 denotes a coefficient related to a leakage flux distribution in the core under short-circuit sinusoidal excitation, and an EMV under an open-circuit condition and an EMV under a short-circuit condition are expressed as follows:
u
m
,
open
=
∑
i
=
1
n
u
m
,
open
,
n
=
k
1
⁢
∑
i
=
1
n
u
open
,
sin
,
n
=
k
1
⁢
u
open
,
u
m
,
short
=
∑
i
=
1
n
u
m
,
short
,
n
=
k
2
⁢
∑
i
=
1
n
u
short
,
sin
,
n
=
k
2
⁢
u
short
,
and
the EMV of the section S in the nanocrystalline core under a load condition is expressed as follows:
u
m
,
load
=
k
1
⁢
u
open
+
k
2
⁢
u
short
;
and
an integral unit configured to express, through an integral operation, the average magnetic flux density in the section S in the core as follows:
B
ave
(
t
)
=
1
S
⁢
∫
u
m
,
load
⁢
dt
=
1
S
⁢
∫
(
k
1
⁢
u
open
+
k
2
⁢
u
short
)
⁢
dt
.

165 more elements

Dependencies are inferred from the claim text.

Facts

Application: 19/354,439Filed 9 Oct 2025
Priority: CN 202411408843510 Oct 2024
Published: 23 Apr 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

G01R 33/02
Arrangements or instruments for measuring magnetic variables: measuring direction or magnitude of magnetic fields or magnetic flux
G01R 31/52
Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections: testing…
G01R 31/54
Testing of electric apparatus, lines, cables or components for short-circuits, continuity, leakage current or incorrect line connections: testing…
G01R 33/0064
Arrangements or instruments for measuring magnetic variables: comprising means for performing simulations, e.g. of the magnetic variable to be…

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