CN115480201A - Method for measuring and correcting alternating current resistance of high-frequency magnetic element winding - Google Patents
Method for measuring and correcting alternating current resistance of high-frequency magnetic element winding Download PDFInfo
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- CN115480201A CN115480201A CN202110664956.1A CN202110664956A CN115480201A CN 115480201 A CN115480201 A CN 115480201A CN 202110664956 A CN202110664956 A CN 202110664956A CN 115480201 A CN115480201 A CN 115480201A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R35/00—Testing or calibrating of apparatus covered by the other groups of this subclass
- G01R35/02—Testing or calibrating of apparatus covered by the other groups of this subclass of auxiliary devices, e.g. of instrument transformers according to prescribed transformation ratio, phase angle, or wattage rating
Abstract
The invention discloses a method for measuring and correcting alternating current resistance of a high-frequency magnetic element winding, which comprises the following steps: measuring the leakage impedance of the winding to be measured; measuring and obtaining a frequency characteristic curve of the total leakage impedance of the measured winding and the auxiliary winding; obtaining characteristic parameters in the total leakage impedance of the measured winding and the auxiliary winding according to frequency characteristic curve fitting; calculating an error coefficient according to the characteristic parameters; and calculating the alternating current resistance of the winding to be detected according to the leakage impedance and the error coefficient of the winding to be detected. The method can effectively improve the measurement precision and the measurement frequency range of the alternating current resistance of the high-power high-frequency magnetic element winding, and reduce the influence of the coupling capacitance between the auxiliary winding and the measured winding on the measurement precision.
Description
Technical Field
The invention relates to a method for measuring and correcting alternating current resistance of a high-frequency magnetic element winding, belonging to the field of parameter measurement of magnetic elements such as transformers, inductors and the like.
Background
The improvement of the working frequency of magnetic elements such as a transformer, an inductor and the like is a main means for greatly reducing the volume and the mass of the magnetic elements, and provides possibility for improving the power density of a system and reducing the cost of the system. In the design of high-power high-frequency magnetic elements, the litz wire winding is an effective method for reducing the loss of the high-frequency winding. The complex structure of the litz wire winding makes the calculation of the alternating current resistance of the winding very difficult, so that the research on a reliable winding loss measuring method has important significance.
In order to reduce the influence of the induced voltage in the magnetic element on the measurement accuracy of the alternating current resistance of the winding, an auxiliary winding is arranged on the magnetic element, so that an additional measurement node is introduced, and the method is an effective method for improving the measurement accuracy. The coupling degree of the auxiliary winding and the measured winding determines the measurable winding resistance value range and frequency range, however, the coupling capacitance between the auxiliary winding and the measured winding limits the increase of the measuring frequency, and the capacitive current injected into the auxiliary winding through the coupling capacitance in a high frequency band causes the measurement accuracy of the alternating current resistance to be reduced. The conventional winding alternating current resistance measuring method based on the auxiliary winding is influenced by a coupling capacitor, and the winding alternating current resistance of a high frequency band cannot be accurately measured.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the method for measuring and correcting the alternating current resistance of the high-frequency magnetic element winding can effectively improve the measurement precision and the measurement frequency range of the alternating current resistance of the high-power high-frequency magnetic element winding and reduce the influence of the coupling capacitance between the auxiliary winding and the measured winding on the measurement precision.
The invention adopts the following technical scheme for solving the technical problems:
a high-frequency magnetic element winding alternating current resistance measurement and correction method comprises the steps that an auxiliary winding is arranged in a high-frequency magnetic element, and the alternating current resistance value of a winding to be measured is corrected by considering the influence of coupling capacitance between the auxiliary winding and the winding to be measured; the method comprises the following steps:
and 5, calculating the alternating current resistance of the winding to be detected according to the leakage impedance and the error coefficient of the winding to be detected.
As a preferred embodiment of the present invention, in step 1, the leakage impedance of the winding to be measured is measured by the impedance measuring instrument, the low potential interface and the voltage measurement reference ground interface of the current excitation branch of the impedance measuring instrument are connected to the same end of the winding to be measured, the voltage measurement point interface of the impedance measuring instrument is connected to one end of the auxiliary winding, the other ends of the winding to be measured and the auxiliary winding are shorted with each other and connected to the high potential interface of the current excitation branch of the impedance measuring instrument, and the shorted end of the winding to be measured and the auxiliary winding is the end with the same name.
As a preferred embodiment of the present invention, the expression of the leakage impedance of the winding to be measured in step 1 is:
Z AW ＝K c (r 1 +jωl 1 )
wherein, Z AW For the leakage impedance of the winding to be measured, K c In order to be the error coefficient,
c is the equivalent coupling capacitance between the measured winding and the auxiliary winding, r 1 And r 2 Ac resistances of the winding to be measured and the auxiliary winding, respectively,/ 1 And l 2 Leakage inductance of the measured winding and the auxiliary winding respectively, omega is the measuring frequency, omega r Xi is a characteristic parameter, and j is an imaginary number unit.
As a preferred aspect of the present invention, an expression of the total leakage impedance of the detected winding and the auxiliary winding is:
wherein, Z Aa The total leakage impedance of the measured winding and the auxiliary winding, c is the equivalent coupling capacitance between the measured winding and the auxiliary winding, omega is the measurement frequency, omega is r Xi is a characteristic parameter, and j is an imaginary number unit.
As a preferred embodiment of the present invention, the measurement circuit required for calculating the error coefficient in step 4 is: the low potential interface and the voltage measurement reference ground interface of the current excitation branch of the impedance measurement instrument are connected with the same end of the measured winding, the voltage measurement point interface and the high potential interface of the current excitation branch of the impedance measurement instrument are connected with the same end of the auxiliary winding, the other ends of the measured winding and the auxiliary winding are in short circuit, and one end of the measured winding and one end of the auxiliary winding, which are in short circuit, are the same-name end.
As a preferable scheme of the present invention, the ac resistance of the winding to be measured in step 5 is a real part of a ratio of the leakage impedance of the winding to be measured to the error coefficient.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. the method for measuring and correcting the alternating current resistance of the winding considers the influence of the coupling capacitance between the auxiliary winding and the winding to be measured, and improves the measurement precision of the winding resistance.
2. The winding alternating current resistance measurement and correction method expands the frequency range of winding resistance measurement.
Drawings
FIG. 1 shows the leakage impedance Z of the winding under test according to the invention AW Schematic measurement.
Fig. 2 is an equivalent circuit diagram of the measured winding and the auxiliary winding of the present invention.
FIG. 3 is the total leakage impedance Z of the tested winding and the auxiliary winding Aa Schematic measurement.
FIG. 4 shows the total leakage impedance Z of the measured winding and the auxiliary winding according to the present invention Aa The frequency characteristic curve of (2).
Fig. 5 is a flow chart of a method for measuring and correcting the ac resistance of the winding of the high-frequency magnetic element according to the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention. In addition, the technical features involved in the respective embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other. The following describes the embodiments in further detail with reference to the accompanying drawings.
As shown in fig. 1, a schematic diagram of a winding ac resistance measurement method is provided, and this embodiment includes an impedance measuring instrument 3, a measured winding 1, and an auxiliary winding 2. In order to reduce the influence of the leakage magnetic field between the measured winding 1 and the auxiliary winding 2 on the measurement precision and improve the measurement frequency range, the auxiliary winding 2 should be tightly coupled with the measured winding 1. If the winding 1 to be tested is a litz wire winding, the individual wires of the litz wire can be selected as the auxiliary winding 2 of this winding. If the winding 1 to be tested is a copper foil winding, a thin copper foil tightly attached to the winding 1 to be tested can be selected as the auxiliary winding 2, and an insulating layer is arranged between the copper foil winding to be tested and the thin copper foil serving as the auxiliary winding. The external interface of the impedance measuring instrument 3 is a four-terminal impedance measuring interface: h CUR (high potential of current excitation branch), H POT (voltage measurement Point), L POT (Voltage measurement reference ground), L CUR (current drive branch low potential). H CUR Common potential terminals B, H connecting the winding 1 to be tested and the auxiliary winding 2 POT Connecting the a terminal, L of the auxiliary winding 2 POT Connecting the A terminal, L of the winding 1 to be tested CUR And the A end of the winding 1 to be tested is connected.
As shown in fig. 2, an equivalent circuit diagram of the measured winding 1 and the auxiliary winding 2 in fig. 1 is given, where an equivalent coupling capacitance c exists between the end a of the measured winding 1 and the end a of the auxiliary winding 2, and the leakage inductance of the measured winding 1 is l 1 The leakage inductance of the auxiliary winding 2 is l 2 The alternating current resistances of the measured winding 1 and the auxiliary winding 2 at the measurement frequency ω are r 1 And r 2 。
According to the equivalent circuit shown in FIG. 2, the impedance measured by the impedance measuring instrument 3 in FIG. 1 is the leakage impedance Z of the measured winding AW The expression is Z AW ＝K c (r 1 +jωl 1 ). Leakage impedance Z of winding to be tested AW Coefficient K in expression c The error coefficient is defined as a function of the equivalent circuit parameter shown in fig. 2. Error coefficient K c The expression of (a) is:
wherein
ω is the measurement frequency. According to the leakage impedance Z of the winding to be tested AW If the equivalent coupling capacitance c is not considered, the error coefficient K c =1, leakage impedance Z of winding to be measured AW The real part of the voltage is the alternating current resistance r of the winding 1 to be tested 1 . However, in practical measurement systems, the equivalent coupling capacitance c inevitably exists when the measurement frequency ω approaches the resonance frequency ω r Time, error coefficient K c Tends to-j/(2 xi) to cause the leakage impedance Z of the measured winding AW Deviation of the real part from the ac resistance r of the winding 1 under test 1 。
To correct the error coefficient K c The resulting measurement error of the AC resistance requires obtaining the coefficient K at the measurement frequency omega c The actual value of (c). FIG. 3 shows the calculated error coefficient K c The required measurement circuitry. In FIG. 3, L of the impedance measuring instrument 3 CUR And L POT The ends of the winding are connected with the A end of the winding 1 to be measured and the impedance measuring instrument 3H POT And H CUR The end is connected with the end a of the auxiliary winding 2, and the end B of the winding 1 to be tested is connected with the end B of the auxiliary winding 2. The impedance measured by the impedance measuring instrument 3 in FIG. 3 is the total leakage impedance Z of the measured winding and the auxiliary winding Aa The expression is
Total leakage impedance Z of tested winding and auxiliary winding Aa Contains 3 unknown parameters: c. omega r ξ, the unknown parameter can be measured by the total leakage impedance Z Aa Is fitted to the frequency characteristic curve of (2). FIG. 4 shows the total leakage impedance Z in an embodiment Aa The frequency characteristic measurement curve of (1) can be fitted to obtain omega according to the characteristic curve r Actual value of ξ.
Curve fitting according to fig. 4 to obtain ω r And xi, i.e. the calculable coefficient K c The actual value of (2), then the measured winding leakage impedance Z AW And error coefficient K c The real part of the ratio is the actual value of the alternating current resistance of the winding 1 to be tested.
According to the above implementation steps, fig. 5 shows the winding ac resistance measurement steps of the present invention: measuring the leakage impedance Z of the winding to be measured AW (ii) a Measuring to obtain total leakage impedance Z of the measured winding and the auxiliary winding Aa The frequency characteristic curve of (1); according to the total leakage impedance Z of the measured winding and the auxiliary winding Aa Obtaining total leakage impedance Z by fitting frequency characteristic curve Aa Middle characteristic parameter omega r And xi; according to the characteristic parameter omega r And xi fitting value calculation error coefficient K c (ii) a And calculating the alternating current resistance of the winding to be measured.
The above embodiments are only for illustrating the technical idea of the present invention, and the technical idea of the present invention is not limited thereto, and any modifications made on the basis of the technical solution according to the technical idea of the present invention fall within the protective scope of the present invention.
Claims (6)
1. A high frequency magnetic element winding alternating current resistance measurement correction method, set up the auxiliary winding in the high frequency magnetic element, consider the influence of coupling capacitance between auxiliary winding and winding to be measured, correct the alternating current resistance value of the winding to be measured; the method is characterized by comprising the following steps:
step 1, measuring the leakage impedance of a winding to be measured;
step 2, measuring and obtaining a frequency characteristic curve of the total leakage impedance of the measured winding and the auxiliary winding;
step 3, fitting according to the frequency characteristic curve in the step 2 to obtain characteristic parameters in the total leakage impedance of the measured winding and the auxiliary winding;
step 4, calculating an error coefficient according to the characteristic parameters;
and 5, calculating the alternating current resistance of the winding to be detected according to the leakage impedance and the error coefficient of the winding to be detected.
2. The method for measuring and correcting the alternating current resistance of the winding of the high-frequency magnetic element according to claim 1, wherein in the step 1, the leakage impedance of the winding to be measured is measured by an impedance measuring instrument, a low potential interface of a current excitation branch of the impedance measuring instrument and a voltage measurement reference ground interface of the impedance measuring instrument are connected to the same end of the winding to be measured, a voltage measurement point interface of the impedance measuring instrument is connected to one end of the auxiliary winding, the other ends of the winding to be measured and the auxiliary winding are in short circuit with each other and are connected to a high potential interface of the current excitation branch of the impedance measuring instrument, and the end of the winding to be measured and the auxiliary winding in short circuit with each other are the same-name end.
3. The method for measuring and correcting the alternating current resistance of the winding of the high-frequency magnetic element according to claim 1, wherein the leakage impedance of the measured winding in step 1 is expressed by:
Z AW ＝K c (r 1 +jωl 1 )
wherein Z is AW For the leakage impedance of the winding to be measured, K c In order to be the error coefficient,
c is the equivalent coupling capacitance between the measured winding and the auxiliary winding, r 1 And r 2 Ac resistances of the winding to be measured and the auxiliary winding, respectively,/ 1 And l 2 Leakage inductance of the measured winding and the auxiliary winding respectively, omega is the measuring frequency, omega r Xi is a characteristic parameter, and j is an imaginary number unit.
4. The method for measuring and correcting the alternating current resistance of the high-frequency magnetic element winding according to claim 1, wherein the expression of the total leakage impedance of the measured winding and the auxiliary winding is as follows:
wherein, Z Aa The total leakage impedance of the measured winding and the auxiliary winding, c is the equivalent coupling capacitance between the measured winding and the auxiliary winding, omega is the measurement frequency, omega is r Xi is a characteristic parameter, and j is an imaginary number unit.
5. The method for measuring and correcting the alternating current resistance of the winding of the high-frequency magnetic element according to claim 1, wherein the measuring circuits required for calculating the error coefficient in step 4 are: the low potential interface and the voltage measurement reference ground interface of the current excitation branch of the impedance measuring instrument are connected with the same end of the measured winding, the voltage measurement point interface and the high potential interface of the current excitation branch of the impedance measuring instrument are connected with the same end of the auxiliary winding, the other ends of the measured winding and the auxiliary winding are in short circuit with each other, and the end of the measured winding and the auxiliary winding in short circuit with each other is the same-name end.
6. The method for measuring and correcting the AC resistance of the winding of the high-frequency magnetic element according to claim 1, wherein the AC resistance of the winding to be measured in step 5 is a real part of a ratio of a leakage impedance of the winding to be measured to an error coefficient.
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| CN202110664956.1A CN115480201A (en) | 2021-06-16 | 2021-06-16 | Method for measuring and correcting alternating current resistance of high-frequency magnetic element winding |
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| CN202110664956.1A CN115480201A (en) | 2021-06-16 | 2021-06-16 | Method for measuring and correcting alternating current resistance of high-frequency magnetic element winding |
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