Method and device for determining magnetic core loss of inductive element of integrated circuit power supply system

文档序号：1830193 发布日期：2021-11-12 浏览：19次中文

阅读说明：本技术 集成电路电源系统电感元件的磁芯损耗的确定方法及装置 (Method and device for determining magnetic core loss of inductive element of integrated circuit power supply system ) 是由王芬于 2021-10-19 设计创作，主要内容包括：本申请提出了这样一种集成电路电源中电感元件的磁芯损耗的确定方法,可包括：向用于集成电路电源系统的电感元件的磁芯中施加具有周期性变化的电流。在电流的作用下,采集磁芯的磁滞回线的多个特征点,其中磁滞回线表示作用于磁芯的磁场强度和磁芯产生的磁感应强度的变化关系。根据多个特征点,确定用于拟合磁滞回线的S曲线的参数,以获得磁滞回线的方程。根据磁滞回线的方程,并基于磁芯损耗的定义,对所述磁滞回线进行积分,以确定磁芯的平均功率损耗。本申请避免了现有技术中在直流偏置的情况下,难以准确获得磁芯损耗的问题,为确定电感元件的磁芯损耗提供了便捷且精确的方式。(The application provides a method for determining core loss of an inductive element in an integrated circuit power supply, which comprises the following steps: a current having a periodic variation is applied to a magnetic core of an inductive element for an integrated circuit power supply system. Under the action of the current, a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core are acquired, wherein the magnetic hysteresis loop represents the change relation between the intensity of the magnetic field acting on the magnetic core and the intensity of magnetic induction generated by the magnetic core. And determining parameters for fitting an S-curve of the hysteresis loop according to the plurality of characteristic points to obtain an equation of the hysteresis loop. The hysteresis loop is integrated according to the equation for the hysteresis loop and based on the definition of the core loss to determine the average power loss of the core. The problem that magnetic core loss is difficult to accurately obtain in the prior art under the condition of direct current bias is avoided, and a convenient and accurate mode is provided for determining the magnetic core loss of the inductance element.)

1. A method of determining core loss of an inductive element in an integrated circuit power supply, comprising:

applying a current having a periodic variation to a magnetic core of an inductive element for an integrated circuit power supply system;

under the action of the current, acquiring a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core, wherein the magnetic hysteresis loop represents the variation relation between the magnetic field intensity acting on the magnetic core and the magnetic induction intensity generated by the magnetic core;

determining parameters for fitting an S curve of the hysteresis loop according to the characteristic points to obtain an equation of the hysteresis loop; and

integrating the hysteresis loop according to the equation of the hysteresis loop and based on the definition of the core loss to determine the average power loss of the core.

2. The method of claim 1, wherein said collecting a plurality of characteristic points of a hysteresis loop of said core under said current comprises:

in a plurality of periods of the current, a first measuring point, a second measuring point, a third measuring point, a fourth measuring point, a fifth measuring point, a sixth measuring point, a seventh measuring point and an eighth measuring point which are used for preliminarily characterizing a hysteresis loop of the magnetic core are respectively and sequentially collected; and

and respectively carrying out averaging processing on the plurality of first measurement points, the plurality of second measurement points, the plurality of third measurement points, the plurality of fourth measurement points, the plurality of fifth measurement points, the plurality of sixth measurement points, the plurality of seventh measurement points and the plurality of eighth measurement points to obtain a first characteristic point, a second characteristic point, a third characteristic point, a fourth characteristic point, a fifth characteristic point, a sixth characteristic point, a seventh characteristic point and an eighth characteristic point which are used for stably characterizing the hysteresis loop of the magnetic core.

3. The method according to claim 2, wherein the characteristic point is a set of pairs of magnetic field intensity values applied to the magnetic core and magnetic induction intensity values generated by the magnetic core, the pairs having a correspondence relationship; wherein the feature points include:

the first characteristic point is composed of a magnetic field intensity value corresponding to the magnetic field intensity value generated by the magnetic core in the magnetization process when the magnetic induction intensity value reaches reverse saturation and a reverse magnetic induction intensity saturation value of the magnetic core in the magnetization process;

the second characteristic point is composed of a value zero and a residual magnetic induction strength value of the magnetic core in the magnetization process;

the third characteristic point is composed of a coercive force value of the material of the magnetic core in the magnetization process and a numerical value of zero;

the fourth characteristic point is composed of a magnetic field intensity value corresponding to the magnetic field intensity value generated by the magnetic core in the magnetization process when the magnetic induction intensity value reaches the forward saturation value and the forward magnetic induction intensity saturation value of the magnetic core in the magnetization process;

the fifth characteristic point is composed of a magnetic field intensity value corresponding to the magnetic field intensity value generated by the magnetic core when the magnetic field intensity value reaches the forward saturation value in the demagnetization process and the forward magnetic induction intensity saturation value of the magnetic core in the demagnetization process;

the sixth characteristic point is composed of a value zero and a residual magnetic induction strength value of the magnetic core in the demagnetization process;

the seventh characteristic point consists of a coercive force value of the material of the magnetic core in the demagnetization process and a numerical value of zero; and

and the eighth characteristic point is formed by the magnetic induction intensity value generated by the magnetic core in the demagnetization process and the magnetic field intensity value corresponding to the magnetic core when the magnetic induction intensity value reaches reverse saturation, and the reverse magnetic induction intensity saturation value of the magnetic core in the demagnetization process.

4. The method of claim 3, wherein the S-curve is:

，

wherein a, b, c and d each represent a parameter defining the S-curve,eis a natural constant and is a natural constant,xthe variable is represented by a number of variables,yrepresents the S curve withxThe result of the change of (2).

5. The method of claim 4, wherein determining the parameters of the S-curve for fitting the hysteresis loop to obtain the hysteresis loop comprises:

respectively substituting the first characteristic point, the second characteristic point, the third characteristic point and the fourth characteristic point into the S curve to determine an initial value of a parameter of the S curve corresponding to the magnetization process;

determining the accurate value of the parameter of the S curve corresponding to the magnetization process by adopting a Newton iteration method so as to determine the magnetization curve equation of the magnetic core;

respectively substituting the fifth characteristic point, the sixth characteristic point, the seventh characteristic point and the eighth characteristic point into the S curve to determine an initial value of a parameter of the S curve corresponding to the demagnetization process;

determining the accurate value of the parameter of the S curve corresponding to the demagnetization process by adopting a Newton iteration method so as to determine the demagnetization curve equation of the magnetic core; and

and integrating the magnetization curve equation and the demagnetization curve equation to obtain a magnetic hysteresis loop of the magnetic core.

6. An apparatus for determining core loss of an inductive element in an integrated circuit power supply, comprising:

a current supply module for applying a current having a periodic variation to a magnetic core of an inductance element for an integrated circuit power supply system;

the acquisition module is used for acquiring a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core under the action of the current, wherein the magnetic hysteresis loop represents the change relation between the magnetic field intensity acting on the magnetic core and the magnetic induction intensity generated by the magnetic core;

the fitting module is used for determining parameters of an S curve for fitting the hysteresis loop according to the plurality of characteristic points so as to obtain an equation of the hysteresis loop; and

and the loss determining module is used for integrating the hysteresis loop according to the equation of the hysteresis loop and based on the definition of the magnetic core loss so as to determine the average power loss of the magnetic core.

7. The apparatus for determining core loss of an inductive element in an integrated circuit power supply of claim 6, wherein said acquisition module performs steps comprising:

8. The apparatus for determining core loss of an inductive element in an integrated circuit power supply according to claim 7, wherein said characteristic point is a set of pairs having correspondence relationship between a magnetic field intensity value applied to said core and a magnetic induction intensity value generated by said core; wherein the feature points include:

the second characteristic point is composed of a value zero and a residual magnetic induction strength value of the magnetic core in the magnetization process;

the third characteristic point is composed of a coercive force value of the material of the magnetic core in the magnetization process and a numerical value of zero;

the sixth characteristic point is composed of a value zero and a residual magnetic induction strength value of the magnetic core in the demagnetization process;

the seventh characteristic point consists of a coercive force value of the material of the magnetic core in the demagnetization process and a numerical value of zero; and

9. The apparatus for determining core loss of an inductive element in an integrated circuit power supply of claim 8, wherein said S-curve is:

，

10. The apparatus of claim 9, wherein the fitting module performs the steps of:

and integrating the magnetization curve equation and the demagnetization curve equation to obtain a magnetic hysteresis loop of the magnetic core.

Technical Field

The present disclosure relates to the field of integrated circuit technologies, and in particular, to a method and an apparatus for determining a magnetic core loss of an inductive element of an integrated circuit power supply system.

Background

The core loss of the inductive element of the system-level integrated circuit power system has a nonlinear characteristic, so that the calculation process is difficult, and a more accurate core loss value is difficult to obtain. Traditionally, the core loss of an inductive element is estimated using the Steinmetz equation, i.e.WhereinIs the average power loss per unit time per unit volume of the magnetic core, k,Andall are coefficients related to the magnetic core material, f is the working frequency of the transformer under sinusoidal excitation,the maximum flux density at which the transformer core operates under sinusoidal excitation. However, the Steinmetz formula is only suitable for sinusoidal excitation, and the excitation current waveform passed by the core of the inductance element of the system-level integrated circuit power supply system is often not a sine wave, so that a large error inevitably exists if the core loss value is estimated by using the Steinmetz formula, and in addition, the power loss of the core is also greatly influenced by the direct current bias.

Considering that the loss caused by the motion of the domain wall in the magnetic core of the inductive element is directly related to the rate of change of the magnetic field with time, the Steinmetz equation is improved to a generalized Steinmetz equation, i.e. the equation of SteinmetzWhere T is the period of the excitation current waveform,is a peak value of the magnetic flux density,、andall are coefficients related to the core material. In fact、Andis variable, however the generalized Steinmetz formula will do、Andit is treated as a constant so that there is a large error in using the generalized Steinmetz equation under dc bias conditions. For example, FIG. 2 is a schematic diagram of a triangular waveform of the excitation current through the core with the input current cut-off distorted, and the generalized Steinmetz equation is shown for the case of different DC offsets of the triangular waveform of the current、Andas well as differences. And, as shown in FIG. 2, from 0 torTIn the time period, the magnetic flux density and the current generated by the inductance coil of the magnetic core satisfy the following relation:whereinrIs a scaling factor of less than 1 and,in order to achieve a magnetic permeability in a vacuum,Nis the number of turns of a coil wound on a core for preparing an inductive component of an integrated circuit power system, and I (t) isThe operating waveform of the current loaded on the inductive element of the integrated circuit power system,to be wound oniForming on the segment magnetic coreiThe length of the segment inductive element is such that,is as followsiRelative permeability of the segment core. Thus, from 0 torTThe time period, the rate of change of the magnetic field with time due to the loss caused by the movement of the magnetic domain wall in the magnetic core of the inductance element, is 0, i.e., the integral in the time period is 0, that is, there is no energy loss in the time period according to the above formula. However, it is actually 0 torTTime periods, some residual loss due to relaxation phenomena may result. In summary, when the input current waveform is distorted and the dc bias is applied, the calculation of the core loss using the generalized Steinmetz equation is still inaccurate.

Disclosure of Invention

The present application provides a method and apparatus for determining core loss of an inductive element of an integrated circuit power system, which is directed to solving, or in part solving, the above problems or at least one other deficiency of the prior art.

The application provides a method for determining core loss of an inductive element in an integrated circuit power supply, which comprises the following steps:

a current having a periodic variation is applied to a magnetic core of an inductive element for an integrated circuit power supply system. Under the action of the current, a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core are acquired, wherein the magnetic hysteresis loop represents the change relation between the intensity of the magnetic field acting on the magnetic core and the intensity of magnetic induction generated by the magnetic core. And determining parameters for fitting an S-curve of the hysteresis loop according to the plurality of characteristic points to obtain an equation of the hysteresis loop. The hysteresis loop is integrated according to the equation for the hysteresis loop and based on the definition of the core loss to determine the average power loss of the core.

In some embodiments, acquiring multiple characteristic points of the hysteresis loop of the magnetic core under the action of the current may include:

in a plurality of current periods, sequentially collecting a first measuring point, a second measuring point, a third measuring point, a fourth measuring point, a fifth measuring point, a sixth measuring point, a seventh measuring point and an eighth measuring point which are used for preliminarily characterizing a hysteresis loop of the magnetic core respectively; and averaging the plurality of first measurement points, the plurality of second measurement points, the plurality of third measurement points, the plurality of fourth measurement points, the plurality of fifth measurement points, the plurality of sixth measurement points, the plurality of seventh measurement points and the plurality of eighth measurement points respectively to obtain a first characteristic point, a second characteristic point, a third characteristic point, a fourth characteristic point, a fifth characteristic point, a sixth characteristic point, a seventh characteristic point and an eighth characteristic point for stably characterizing the hysteresis loop of the magnetic core.

In some embodiments, the S-curve is:

，

wherein a, b, c and d each represent a parameter defining an S-curve,eis a natural constant and is a natural constant,xthe variable is represented by a number of variables,yrepresents the S curve withxThe result of the change of (2).

In some embodiments, determining a parameter for fitting an S-curve of a hysteresis loop to obtain an equation of the hysteresis loop based on the plurality of feature points may include:

according to the attribute that the output result converges to a fixed value when the variable of the S curve tends to infinity, setting a magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the magnetizing process reaching reverse saturation and a magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the demagnetizing process reaching reverse saturation as minus infinity, and setting a magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the magnetizing process reaching forward saturation and a magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the demagnetizing process reaching forward saturation as plus infinity; respectively substituting the first characteristic point, the second characteristic point, the third characteristic point and the fourth characteristic point into the S curve to determine an initial value of a parameter of the S curve corresponding to the magnetization process; determining the accurate value of the parameter of the S curve corresponding to the magnetization process by adopting a Newton iteration method so as to determine the magnetization curve equation of the magnetic core; respectively substituting the fifth characteristic point, the sixth characteristic point, the seventh characteristic point and the eighth characteristic point into the S curve to determine an initial value of a parameter of the S curve corresponding to the demagnetization process; determining the accurate value of the parameter of the S curve corresponding to the demagnetization process by adopting a Newton iteration method so as to determine the demagnetization curve equation of the magnetic core; and integrating the magnetization curve equation and the demagnetization curve equation to obtain a magnetic hysteresis loop of the magnetic core.

In some embodiments, the newton iteration method may include: and respectively determining each parameter of the S curve as an iteration variable. From the iteration variable, a newton iteration formula is determined, where the newton iteration formula represents a formula for deriving a next value of the iteration variable from a previous value of the iteration variable. Determining an objective function of the iteration variable, and taking a value of the iteration variable corresponding to a module value as an accurate value of a parameter of the S curve in response to the condition that the module value of the objective function is smaller than a preset threshold value; wherein the objective function characterizes a difference between a calculated value at the feature point position obtained using an S-curve with the iteration variable as a parameter and a measured value at the feature point position.

In some embodiments, the core loss calculation is formulated as:

，

wherein the content of the first and second substances,the average power loss of the magnetic core per unit volume and unit time is f, the waveform frequency of the current is f, L is an integral path integrated along a hysteresis loop, B is the magnetic induction intensity generated by the magnetic core, and H is the magnetic field intensity generated by the current loaded on an inductance element for the integrated circuit power supply system.

The application also provides a device for determining the magnetic core loss of the inductance element in the integrated circuit power supply, which comprises a current supply module, an acquisition module, a fitting module and a loss determination module. The current supply module is used for applying current with periodic variation to a magnetic core of an inductance element for an integrated circuit power supply system. The acquisition module is used for acquiring a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core under the action of current, wherein the magnetic hysteresis loop represents the change relation between the magnetic field intensity acting on the magnetic core and the magnetic induction intensity generated by the magnetic core. The fitting module is used for determining parameters of an S curve for fitting the hysteresis loop according to the plurality of characteristic points so as to obtain an equation of the hysteresis loop. The loss determination module is used for integrating the hysteresis loop according to an equation of the hysteresis loop and based on the definition of the magnetic core loss so as to determine the average power loss of the magnetic core.

In some embodiments, the step of executing the acquisition module may comprise: in a plurality of current periods, sequentially collecting a first measuring point, a second measuring point, a third measuring point, a fourth measuring point, a fifth measuring point, a sixth measuring point, a seventh measuring point and an eighth measuring point which are used for preliminarily characterizing a hysteresis loop of the magnetic core respectively; and respectively carrying out averaging processing on the plurality of first measurement points, the plurality of second measurement points, the plurality of third measurement points, the plurality of fourth measurement points, the plurality of fifth measurement points, the plurality of sixth measurement points, the plurality of seventh measurement points and the plurality of eighth measurement points to obtain a first characteristic point, a second characteristic point, a third characteristic point, a fourth characteristic point, a fifth characteristic point, a sixth characteristic point, a seventh characteristic point and an eighth characteristic point which are used for stably characterizing the hysteresis loop of the magnetic core.

In some embodiments, the S-curve is:

，

In some embodiments, the performing step of the fitting module may include:

In some embodiments, the core loss calculation is formulated as:

，

wherein the content of the first and second substances,the average power loss of the magnetic core in unit volume and unit time is shown as f, the waveform frequency of the current is shown as L, the integral path of the integral along the hysteresis loop is shown as L, the magnetic induction intensity generated by the magnetic core is shown as B, and the magnetic field intensity is shown as H.

According to the technical scheme of the embodiment, at least one of the following advantages can be obtained.

According to the method and the device for determining the magnetic core loss of the inductive element of the integrated circuit power supply system, a plurality of characteristic points of the magnetic core of the inductive element in the integrated circuit power supply system are collected, and then parameters of an S curve used for fitting a magnetic core hysteresis loop are determined through the characteristic points so as to fit the hysteresis loop of the magnetic core, and finally, the magnetic core loss of the inductive element can be obtained through a method of integrating the hysteresis loop directly according to the definition of the magnetic core loss. Based on the above, the problem that the magnetic core loss is difficult to accurately obtain under the condition of direct current bias in the prior art can be solved, and a convenient and accurate mode is provided for determining the magnetic core loss of the inductance element.

Drawings

Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, with reference to the accompanying drawings in which:

FIG. 1 is a flow chart of a method of determining core loss of an inductive element of an integrated circuit power system according to an exemplary embodiment of the present application;

FIG. 2 is a triangular waveform schematic of an excitation current through a magnetic core with input current waveform cutoff distortion;

FIG. 3 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 2 for a method of determining core loss of an inductive element of an integrated circuit power system according to an exemplary embodiment of the present application;

FIG. 4 is a triangular waveform schematic of the excitation current through the core without distortion of the input current waveform;

FIG. 5 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 4 for a method of determining core loss of an inductive element of an integrated circuit power supply system according to an exemplary embodiment of the present application;

FIG. 6 is a triangular waveform schematic of the excitation current through the core with saturation distortion of the input current waveform;

FIG. 7 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 6 for a method of determining core loss of an inductive element of an integrated circuit power supply system in accordance with an exemplary embodiment of the present application;

FIG. 8 is a triangular waveform schematic of the excitation current through the core with bidirectional distortion of the input current waveform;

FIG. 9 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 8 for a method of determining core loss of an inductive element of an integrated circuit power supply system in accordance with an exemplary embodiment of the present application; and

fig. 10 is a schematic diagram of a structure of an apparatus for determining core loss of an inductive element of an integrated circuit power supply system according to an exemplary embodiment of the present application.

Detailed Description

For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

In the drawings, the size, dimension, and shape of elements have been slightly adjusted for convenience of explanation. The figures are purely diagrammatic and not drawn to scale. As used herein, the terms "approximately", "about" and the like are used as table-approximating terms and not as table-degree terms, and are intended to account for inherent deviations in measured or calculated values that would be recognized by one of ordinary skill in the art. In addition, in the present application, the order in which the processes of the respective steps are described does not necessarily indicate an order in which the processes occur in actual operation, unless explicitly defined otherwise or can be inferred from the context.

It will be further understood that terms such as "comprising," "including," "having," "including," and/or "containing," when used in this specification, are open-ended and not closed-ended, and specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of" appears after a list of listed features, it modifies that entire list of features rather than just individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including engineering and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

In addition, the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Fig. 1 is a flow chart of a method of determining core loss of an inductive element of an integrated circuit power system according to an exemplary embodiment of the present application.

As shown in fig. 1, the present application provides a method for determining a core loss of an inductive element of an integrated circuit power system, which may include: step S1, a current having a periodic variation is applied to a magnetic core of an inductance element for an integrated circuit power supply system. And step S2, under the action of the current, acquiring a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core, wherein the magnetic hysteresis loop represents the change relation between the magnetic field intensity acting on the magnetic core and the magnetic induction intensity generated by the magnetic core. In step S3, parameters of an S-curve for fitting the hysteresis loop are determined according to the plurality of feature points to obtain an equation of the hysteresis loop. Step S4, integrating the hysteresis loop according to the equation of the hysteresis loop and based on the definition of the core loss to determine the average power loss of the core.

In some embodiments, a current having a periodic variation is first applied to a magnetic core of an inductive element for an integrated circuit power system. The magnetic field intensity value applied to the magnetic core is generated by a current applied to the inductance element for the integrated circuit power supply system, and the waveform of the current is completely the same as the operating waveform of the inductance element for the integrated circuit power supply system. In addition, in many power supply systems of integrated circuits, magnetic elements need to be pre-magnetized and biased by direct current or low frequency according to the requirements of devices such as transistors in the integrated circuits, for example, in a switching power supply circuit of the integrated circuit, the magnetic elements operating under the condition of direct current bias are generally used, so that the input current signals may also have the condition of direct current bias. Based on the method, firstly, a hysteresis loop of the magnetic core of the inductance element is determined according to the working waveform of the current, and then the magnetic core loss of the inductance element is determined by an integral method according to the hysteresis loop.

Further, when the current is applied to the magnetic core of the inductance element, a magnetic field varying with the current is generated in the magnetic core under the action of the current, and thus a certain magnetic core loss is generated. Based on the core loss of the core, a corresponding hysteresis loop may be generated. Of course, different current signals through the core will produce hysteresis loops in different states.

FIG. 2 is a triangular waveform schematic of an excitation current through a magnetic core with input current waveform cutoff distortion; FIG. 3 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 2 for a method of determining core loss of a system inductive element in an integrated circuit power supply according to an exemplary embodiment of the present application; FIG. 4 is a triangular waveform schematic of the excitation current through the core without distortion of the input current waveform; FIG. 5 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 4 for a method of determining core loss of an inductive element of an integrated circuit power supply system according to an exemplary embodiment of the present application; FIG. 6 is a triangular waveform schematic of the excitation current through the core with saturation distortion of the input current waveform; FIG. 7 is a hysteresis loop diagram corresponding to the current waveform shown in FIG. 6 for a method of determining core loss of an inductive element of an integrated circuit power supply system in accordance with an exemplary embodiment of the present application; FIG. 8 is a triangular waveform schematic of the excitation current through the core with bidirectional distortion of the input current waveform; and fig. 9 is a hysteresis loop diagram corresponding to the current waveform shown in fig. 8 for a method of determining core loss of an inductive element of an integrated circuit power supply system according to an exemplary embodiment of the present application.

In some embodiments, as shown in fig. 2, in order to simulate the phenomenon that the bias current applied to the transistor of the integrated circuit is too small, which results in the valley of the signal voltage and current being flattened, the current waveform applied to the core is triangular and is cut-off distorted, and has a duty cycle T, during which the maximum value of the current is TThe minimum value of the current in the period isAnd the difference between the maximum value and the minimum value of the current in the period is. Further, the air conditioner is provided with a fan,for the average current value of the input current, it can be seen that the average current value is larger than zero, in other words, the current signal has a phenomenon of dc offset. In addition, the operating waveform of the current is in the time period 0 to 0rTIn other words, the current signal at this time has a case where the off current is a current value of the period of time. Further, during the period of time when the current is constant, the magnetic field applied to the core is constant, but the magnetization of the core is still proceeding, so that a loss of residual energy still occurs. This is reflected in the hysteresis loop, which, as can be seen in FIG. 3, results in a flat magnetization curveToThe length of the section is equal to the length of the section,toThe segment corresponds to the current operation waveform of the time period 0 to rT. In thatToIn the section, the magnetic field strength H is constant but the magnetic induction strength B rises in the opposite direction(ii) a At the time pointrAfter T, of the corresponding magnetisation curveAt the point, the current value begins to increase, and the magnetic field intensity value H rises along with the rise of the magnetic induction intensity value B until the magnetic field intensity value H rises to the highest pointAt this time, the magnetic induction intensity value B reaches the maximum forward direction; then the current value is gradually reduced until the current value reaches the minimum value, at the moment, the value of the magnetic induction intensity value B is reduced along with the reduction of the magnetic induction intensity value H until the current reaches the cut-off position. It can be seen that the special points of the hysteresis loop may include:toEnd points of segments, i.e.Magnetic field intensity value and magnetic induction intensity value of the spot, andmagnetic field intensity values and magnetic induction intensity values;the position, namely the corresponding magnetic field intensity value and magnetic induction intensity value when the magnetic induction intensity is maximum in the positive direction; magnetic induction intensity value corresponding to the magnetic field intensity value being zero in the magnetization processAt least one of (1) and (b); magnetic field intensity value corresponding to magnetic induction intensity value being zero in magnetization processAt least one of (1) and (b); the magnetic induction intensity value corresponding to the magnetic field intensity value when the magnetic field intensity value is zero in the demagnetization processAt least one of (1) and (b); and the magnetic field intensity value corresponding to the magnetic induction intensity value being zero in the demagnetization processTo (3).

In some embodiments, as shown in FIG. 4, the operating waveform of the current applied to the core is a triangular waveform with an operating period T and a maximum value of the current during the period TThe minimum value of the current in the period isAnd the difference between the maximum value and the minimum value of the current in the period is. Further, the air conditioner is provided with a fan,for the average current value of the input current, it can be seen that the average current value is larger than zero, in other words, the current signal has a phenomenon of dc offset. In addition, in the working cycle of the current, rT is the time point of the peak value, namely the current value corresponding to the rT time isAnd there is no period in which the current signal remains unchanged, in other words, there is no distortion in the current signal applied to the core. This is reflected in the hysteresis loop, and referring to fig. 5, the time rT corresponds to the magnetic induction intensity value and the magnetic field intensity value at which the forward direction of the current applied to the inductance element is maximum, and the magnetic field intensity value decreases as the current value decreases from the time rT to the time TThe induction intensity value B is reduced along with the reduction of the magnetic field intensity value H until the induction intensity value B is lowered to the lowest pointTo (3). It can be seen that the special points of the hysteresis loop may include:the position, namely the magnetic field intensity value and the magnetic induction intensity value corresponding to the time when the current value is increased to the highest value;the position, namely the magnetic field intensity value and the magnetic induction intensity value corresponding to the current value which is reduced to the lowest; magnetic induction intensity value corresponding to the magnetic field intensity value being zero in the magnetization processAt least one of (1) and (b); magnetic field intensity value corresponding to magnetic induction intensity value being zero in magnetization processAt least one of (1) and (b); the magnetic induction intensity value corresponding to the magnetic field intensity value when the magnetic field intensity value is zero in the demagnetization processAt least one of (1) and (b); and the magnetic field intensity value corresponding to the magnetic induction intensity value being zero in the demagnetization processTo (3).

In some embodiments, as shown in fig. 6, in order to simulate the phenomenon that the bias current applied to the transistor of the integrated circuit is too large, which results in the peak of the signal voltage and current being flattened, the waveform of the current applied to the core is triangular and is saturation-distorted, and has a duty cycle T, during which the maximum value of the current is TElectricity in the cycleMinimum value of flow ofAnd the difference between the maximum value and the minimum value of the current in the period is. Further, the air conditioner is provided with a fan,for the average current value of the input current, it can be seen that the average current value is larger than zero, in other words, the current signal has a dc bias phenomenon. During the period T, the working waveform of the current can be seen in the time periodToIn this case, the current signal is kept unchanged, and the current in this period is the saturation distortion current in this period, in other words, the current signal at this time has the saturation distortion. Further, during the period of time when the current is constant, the magnetic field applied to the core is constant, but the magnetization of the core is still proceeding, so that a loss of residual energy still occurs. This is reflected in the hysteresis loop, which, as can be seen in fig. 7, results in a flat magnetization curveToThe length of the section is equal to the length of the section,toThe segments corresponding to time segmentsToThe current operating waveform of (2). In thatToIn section, magnetic field strength valueHMagnetic induction intensity while keeping maximumBUp to the new maximum; at the time pointAfter that, of the corresponding demagnetization curveAt the point, the current value begins to decrease, at which time the magnetic field strength valueHIntensity value according to magnetic inductionBUntil it reaches the lowest pointTo (3). It can be seen that the special points of the hysteresis loop may include:toEnd points of segments, i.e.Magnetic field intensity and magnetic induction intensity of the spot andmagnetic field intensity values and magnetic induction intensity values;magnetic field strength at location, i.e. when current waveform reaches troughValues and magnetic induction intensity values; magnetic induction intensity value corresponding to the magnetic field intensity value being zero in the magnetization processAt least one of (1) and (b); magnetic field intensity value corresponding to magnetic induction intensity value being zero in magnetization processAt least one of (1) and (b); the magnetic induction intensity value corresponding to the magnetic field intensity value when the magnetic field intensity value is zero in the demagnetization processAt least one of (1) and (b); and the magnetic field intensity value corresponding to the magnetic induction intensity value being zero in the demagnetization processTo (3).

In some embodiments, as shown in fig. 8, the amplification factor of the triode of the analog integrated circuit is too large, which causes the signal voltage and current output by the triode to reach saturation upwards and cut off downwards, and the wave crest and wave trough of the output signal are both flattened, and the current waveform loaded on the magnetic core is triangular and is bidirectional distorted, and one working period of the current waveform is T, and the maximum value of the current in the period is TThe minimum value of the current in the period isAnd the difference between the maximum value and the minimum value of the current in the period is. Further, the air conditioner is provided with a fan,for the average current value of the input current, it can be seen that the average current value is larger than zero, in other words, the current signal has a dc bias phenomenon.In the period T of the working waveform of the current, the working waveform of the current can be seen to be between 0 and TThe current in the time period is the cut-off distortion current in the period; and the operating waveform of the current is as followsToThe current value in the time period is the saturated distortion current in the period, in other words, the case where the current signal passing through the amplifier has bidirectional distortion. Further, during the period of time when the current is constant, the magnetic field applied to the core is constant, but the magnetization of the core is still proceeding, so that a loss of residual energy still occurs. This is reflected in the hysteresis loop, which, as can be seen in fig. 9, results in a flat magnetization curveToSegment, and a flat demagnetization curveToAnd (4) section.ToThe segments correspond to time segments 0 to 0The current operating waveform of (a);toThe segments corresponding to time segmentsToThe current operating waveform of (2). In thatToIn the section, the magnetic induction B rises in the opposite direction but the magnetic field strength H remains at a minimum; at the time pointThen, the current value is continuously increased, and the magnetic field intensity H is increased along with the increase of the magnetic induction intensity B until the magnetic field intensity H is increased to the highest pointAt this time, the magnetic induction B reaches the maximum value; further, the intensity of the earth magnetic field H is kept the maximum in the forward direction, but the magnetic induction B is further increased until the maximum magnetic induction reachesAt least one of (1) and (b); further, the magnetic induction B decreases with decreasing magnetic induction H until reachingAt this point, the magnetic induction B reaches the inverse minimum. It can be seen that the special points of the hysteresis loop may include:toEnd points of segments, i.e.Magnetic field intensity value and magnetic induction intensity value of the spot, andmagnetic field intensity values and magnetic induction intensity values;toEnd points of segments, i.e.Magnetic field intensity and magnetic induction intensity of the spot andmagnetic field intensity values and magnetic induction intensity values; magnetic induction intensity value corresponding to zero magnetic field intensity in magnetization processAt least one of (1) and (b); magnetic field intensity value corresponding to zero magnetic induction intensity in magnetization processAt least one of (1) and (b); magnetic induction intensity value corresponding to zero magnetic field intensity in demagnetization processAt least one of (1) and (b); and the corresponding magnetic field intensity value when the magnetic induction intensity is zero in the demagnetization processTo (3).

In summary, the characteristic point of the hysteresis loop of the inductance element core is determined in relation to the operating waveform of the current signal passing through the inductance element core. In other words, the operating waveform of the current signal passing through the magnetic core of the inductance element can be any type, and there may also be a dc offset phenomenon, so that it is necessary to determine the hysteresis loop of the corresponding magnetic core of the inductance element according to the operating waveform of the current signal passing through the magnetic core of the inductance element.

In some embodiments, the S-curve has a characteristic of being steep in the middle, gentle at both ends, and converging to a fixed value, respectively, and the hysteresis loop of the magnetic core includes a magnetization curve and a demagnetization curve each having the same characteristics as the S-curve. Based on this, this application uses S curve to fit magnetization curve and demagnetization curve respectively, and then can constitute the hysteresis loop of magnetic core.

In some embodiments, first, in a plurality of current cycles, a first measurement point, a second measurement point, a third measurement point, a fourth measurement point, a fifth measurement point, a sixth measurement point, a seventh measurement point, and an eighth measurement point for preliminarily characterizing a hysteresis loop of a magnetic core are sequentially collected; and averaging the plurality of first measurement points, the plurality of second measurement points, the plurality of third measurement points, the plurality of fourth measurement points, the plurality of fifth measurement points, the plurality of sixth measurement points, the plurality of seventh measurement points and the plurality of eighth measurement points respectively to obtain a first characteristic point, a second characteristic point, a third characteristic point, a fourth characteristic point, a fifth characteristic point, a sixth characteristic point, a seventh characteristic point and an eighth characteristic point for stably characterizing the hysteresis loop of the magnetic core. When the current applied to the core is a current having an off-distortion operating waveform, the fourth characteristic point and the fifth characteristic point are the same point, and therefore, it is not necessary to repeat the measurement. When the current applied to the core is a current having a saturated distorted operating waveform, the first characteristic point and the eighth characteristic point thereof are the same point, and therefore, it is not necessary to repeat the measurement. When the current applied to the magnetic core is a current having an undistorted operating waveform, the first characteristic point and the eighth characteristic point are the same point, and the fourth characteristic point and the fifth characteristic point are the same point, so that the repeated measurement is not required.

In some embodiments, the characteristic point is a set of pairs having a correspondence relationship between a magnetic field intensity value applied to the magnetic core and a magnetic induction intensity value generated by the magnetic core. The feature points may include: a first characteristic point consisting of a magnetic field intensity value corresponding to the magnetic field intensity value when the magnetic induction intensity value generated by the magnetic core in the magnetization process reaches reverse saturation, and a reverse magnetic induction intensity saturation value of the magnetic core in the magnetization process; a second characteristic point consisting of a value zero and a residual magnetic induction intensity value of the magnetic core in the magnetization process, wherein the value zero is an external magnetic field intensity value in the magnetization process, and the residual magnetic induction intensity value is a corresponding magnetic induction intensity value of the magnetic core when the external magnetic field intensity value is zero in the magnetization process; a third characteristic point consisting of a coercive force value of the material of the magnetic core in the magnetization process and a numerical value zero, wherein the coercive force value is an external magnetic field strength value which enables the magnetic induction strength value of the magnetic core to be zero in the magnetization process, and the numerical value zero is the magnetic induction strength value of the magnetic core corresponding to the coercive force value of the material of the magnetic core in the magnetization process; a fourth characteristic point which is composed of a magnetic field intensity value corresponding to the magnetic field intensity value generated by the magnetic core in the magnetization process when the magnetic field intensity value reaches the forward saturation value and the forward magnetic field intensity saturation value of the magnetic core in the magnetization process; a fifth characteristic point consisting of a magnetic field intensity value corresponding to the magnetic field intensity value when the magnetic induction intensity value generated by the magnetic core reaches the forward saturation value in the demagnetization process, and the forward magnetic induction intensity saturation value of the magnetic core in the demagnetization process; a sixth characteristic point consisting of a value zero and a residual magnetic induction intensity value of the magnetic core in the demagnetization process, wherein the value zero is an external magnetic field intensity value in the demagnetization process, and the residual magnetic induction intensity value is a magnetic induction intensity value of the magnetic core corresponding to the external magnetic field intensity value when the external magnetic field intensity value is zero in the demagnetization process; a seventh characteristic point consisting of a coercive force value of the material of the magnetic core in the demagnetization process and a numerical value zero, wherein the coercive force value is an external magnetic field strength value which enables the magnetic induction strength value of the magnetic core to be zero in the demagnetization process, and the numerical value zero is the magnetic induction strength value of the magnetic core corresponding to the coercive force value of the material of the magnetic core in the demagnetization process; and an eighth characteristic point consisting of a magnetic field intensity value corresponding to a magnetic field intensity value when the magnetic induction intensity value generated by the magnetic core reaches reverse saturation in the demagnetization process, and a reverse magnetic induction intensity saturation value of the magnetic core in the demagnetization process. Note that, although the saturation magnetic induction values of the cores of the inductance elements made of different materials are different, the saturation magnetic induction values of the cores made of the same material are the same. In other words, the saturation induction value of the magnetic core is determined by the material of the magnetic core. In addition, the coercive force values of the magnetic cores made of the same material are also the same, namely the coercive force is the demagnetizing field strength required when the magnetic induction intensity generated by the magnetic cores is zero; and when the magnetic field intensity is zero, the residual magnetic induction intensity in the magnetic cores made of the same material is the same.

Further, the S-curve is:

，（1）

in formula (1), a, b, c and d each represent a parameter defining an S-curve, e is a natural constant,xthe variable is represented by a number of variables,yrepresents the S curve withxThe result of the change of (2).

Dependent on the in-variation of the S-curvexOutput result when approaching infinityyAnd the attribute of convergence to a fixed value, wherein the magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the magnetization process reaching reverse saturation and the magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the demagnetization process reaching reverse saturation are both set to be negative infinity, and the magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the magnetization process reaching forward saturation and the magnetic field intensity value corresponding to the magnetic induction intensity value generated by the magnetic core in the demagnetization process reaching forward saturation are both set to be positive infinity. And then respectively bringing the first characteristic point, the second characteristic point, the third characteristic point and the fourth characteristic point into the S curve, and determining the initial parameter value of the S curve corresponding to the magnetization process of the magnetic core. And respectively substituting the fifth characteristic point, the sixth characteristic point, the seventh characteristic point and the eighth characteristic point into the S curve, and determining the initial value of the parameter of the S curve corresponding to the demagnetization process of the magnetic core. Furthermore, the accurate values of the parameters of the S curves corresponding to the magnetization process and the demagnetization process of the magnetic core are respectively determined by adopting a Newton iteration method so as to respectively determine a magnetization curve equation and a demagnetization curve equation. And finally, integrating the magnetization curve equation and the demagnetization curve equation to obtain the equation of the magnetic hysteresis loop. Of course, when the current applied to the core is such as to operate with cut-off distortionIn the case of a waveform current, the fourth characteristic point and the fifth characteristic point are the same point and are not distinguished. When the current applied to the magnetic core is a current having a saturated distorted operating waveform, the first characteristic point and the eighth characteristic point thereof are the same point and are not distinguished. When the current applied to the magnetic core is a current having an undistorted operating waveform, the first characteristic point and the eighth characteristic point are the same point, and the fourth characteristic point and the fifth characteristic point are the same point, so that both of them do not need to be distinguished.

Specifically, first, each parameter of the S-curve in the demagnetization process is defined as an iteration variable. From the iteration variable, a newton iteration formula is determined, where the newton iteration formula represents a formula for deriving a next value of the iteration variable from a previous value of the iteration variable. The newton iterative formula can be expressed as:

，（2）

in equation (2), P is an iteration vector,iis a natural number, and is provided with a plurality of groups,represents the variable ofiThe result of the sub-iteration, F is the objective function,is a jacobian matrix of the objective function.

The target function is the difference value between the value of the S curve at the characteristic point position and the measured value, which is calculated by reversing the parameter of the S curve determined by the iterative method, and the smaller the difference value is, the closer the parameter of the S curve determined by the iterative method is to the true value of the measurement at the characteristic point. The objective function can be expressed as:

，（3）

in the formula (3), the first and second groups,f _iexpressing sub-objective function, i is natureNumber, specifically S-curve atiThe difference between the value of each feature point position and the corresponding measured value;the value of the S curve at the position of the characteristic point is calculated in reverse according to the parameters of the S curve determined by an iterative method;is a measurement at the location of the feature point;qthe natural number represents the acceleration factor of the constructed objective function in the iteration process;nthe number of sub-targeting functions, or the number of feature points.

The Jacobian matrix of the objective function can be expressed as:

，（4）

in the formula (4), the first and second groups,represents the second of the objective function FSub objective functionTo iterative variable PmA variable quantityCalculating a partial derivative, herel、mAndnare all natural numbers. Setting the error of the S curve as an iterative target function, and in response to the condition that the module value of the target function is smaller than a threshold value, taking the value of the iterative variable corresponding to the module value as the accurate value of the parameter of the S curve. The target function is the difference between the value of the S curve at the position of the characteristic point and the measured value, which is inversely calculated according to the parameters of the S curve determined by the iterative method, and the S curve determined by the iterative method has the smaller differenceThe closer the parameter is to the true value of the measurement at the feature point, i.e. the modulus valueThe smaller, the closer to the iteration target the representation is, the more accurate the parameters of the obtained S-curve are.

In some embodiments, after obtaining the hysteresis loop, the average power loss of the core can be determined by integrating the hysteresis loop according to the equation of the hysteresis loop and directly according to the definition of the core loss.

Specifically, the core loss calculation formula is:

，（5）

in the formula (5), the first and second groups,the average power loss of the magnetic core in unit volume and unit time is shown, f is the waveform frequency of the current, L is the equation of a hysteresis loop, B is the magnetic induction intensity generated by the magnetic core, and H is the magnetic field intensity.

According to the method for determining the magnetic core loss of the inductive element of the integrated circuit power supply system, a plurality of characteristic points of the magnetic core of the inductive element in the integrated circuit power supply system are collected, and then parameters of an S curve used for fitting a magnetic core hysteresis loop are determined through the characteristic points so as to fit the hysteresis loop of the magnetic core, and finally, the magnetic core loss of the inductive element can be obtained through a method of integrating the hysteresis loop directly according to the definition of the magnetic core loss. Based on the above, the problem that the magnetic core loss is difficult to accurately obtain under the condition of direct current bias in the prior art can be solved, and a convenient and accurate mode is provided for determining the magnetic core loss of the inductance element.

Fig. 10 is a schematic configuration diagram of an apparatus for determining core loss of an inductive element in an integrated circuit power supply according to an exemplary embodiment of the present application.

As shown in fig. 10, the present application further provides a device for determining core loss of an inductive element in an integrated circuit power supply, which may include a current supply module 1, an acquisition module 2, a fitting module 3, and a loss determination module 4. The current supply module 1 is used for applying a current having a periodic variation to a magnetic core of an inductance element for an integrated circuit power supply system. The acquisition module 2 is used for acquiring a plurality of characteristic points of a magnetic hysteresis loop of the magnetic core under the action of current, wherein the magnetic hysteresis loop represents the change relation between the magnetic field intensity acting on the magnetic core and the magnetic induction intensity generated by the magnetic core. The fitting module 3 is configured to determine a parameter of an S-curve for fitting the hysteresis loop according to the plurality of feature points, so as to obtain an equation of the hysteresis loop. The loss determination module 4 is configured to integrate the hysteresis loop according to an equation of the hysteresis loop and based on the definition of the core loss to determine the average power loss of the core.

In some embodiments, the step of executing the acquisition module 2 may include: in a plurality of current periods, sequentially collecting a first measuring point, a second measuring point, a third measuring point, a fourth measuring point, a fifth measuring point, a sixth measuring point, a seventh measuring point and an eighth measuring point which are used for preliminarily characterizing a hysteresis loop of the magnetic core respectively; and respectively carrying out averaging processing on the plurality of first measurement points, the plurality of second measurement points, the plurality of third measurement points, the plurality of fourth measurement points, the plurality of fifth measurement points, the plurality of sixth measurement points, the plurality of seventh measurement points and the plurality of eighth measurement points to obtain a first characteristic point, a second characteristic point, a third characteristic point, a fourth characteristic point, a fifth characteristic point, a sixth characteristic point, a seventh characteristic point and an eighth characteristic point which are used for stably characterizing the hysteresis loop of the magnetic core.

In some embodiments, the S-curve is:

，

In some embodiments, the performing step of the fitting module 3 may include:

In some embodiments, the core loss calculation is formulated as:

，

According to the device for determining the magnetic core loss of the inductive element of the integrated circuit power supply system, a plurality of characteristic points of the magnetic core of the inductive element in the integrated circuit power supply system are collected, and then parameters of an S curve used for fitting a magnetic core hysteresis loop are determined through the characteristic points so as to fit the hysteresis loop of the magnetic core, and finally, the magnetic core loss of the inductive element can be obtained through a method of integrating the hysteresis loop directly according to the definition of the magnetic core loss. Based on the above, the problem that the magnetic core loss is difficult to accurately obtain under the condition of direct current bias in the prior art can be solved, and a convenient and accurate mode is provided for determining the magnetic core loss of the inductance element.

The objects, technical solutions and advantageous effects of the present invention are further described in detail with reference to the above-described embodiments. It should be understood that the above description is only a specific embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

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Method and device for determining magnetic core loss of inductive element of integrated circuit power supply system

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