Current sensor and control method thereof

Abstract

The present application discloses a current sensor and a control method thereof. The current sensor includes a magnetic core and a first coil and a second coil for exciting the magnetic core. The control method includes: applying a first excitation signal to the first coil to excite the magnetic core to alternate saturation; obtaining a detection signal from the magnetic core, wherein the detection signal includes a plurality of mutation zones corresponding to the magnetic core entering and exiting the saturation state and a platform zone located between two adjacent mutation zones; in response to the duration of the platform zone not meeting the preset duration requirement, applying a second excitation signal to the second coil, wherein the second excitation signal is used to increase the duration of the platform zone. The above scheme has obvious resistance to external magnetic field interference and obtains more accurate current information to be measured.

Description

Technical Field

[0001] The present application relates to the technical field of current measurement, and in particular to a current sensor and a control method thereof. Background Art

[0002] Fluxgate current sensors, which utilize the fluxgate principle, have been widely used in various fields due to their high sensitivity, excellent linearity, high resolution, and high precision. In a typical fluxgate current sensor, a single coil is wound around the magnetic core and connected to an H-bridge. Excitation by an AC square wave generates a self-oscillating fluxgate effect for current measurement. However, when used in BMS systems, these sensors are susceptible to interference from external magnetic fields due to the complex busbar structure and harsh electromagnetic environment within the high-voltage box, affecting current sampling accuracy. Summary of the Invention

[0003] In order to solve the above problems, the present application proposes a current sensor and a control method thereof.

[0004] In a first aspect, the present application provides a control method for a current sensor, wherein the current sensor includes a magnetic core and a first coil and a second coil for stimulating the magnetic core, the control method including: applying a first excitation signal to the first coil to stimulate the magnetic core to alternately saturate; obtaining a detection signal from the magnetic core, wherein the detection signal includes a plurality of mutation zones corresponding to the magnetic core entering and exiting a saturation state and a platform zone located between two adjacent mutation zones; in response to the duration of the platform zone not meeting a preset duration requirement, applying a second excitation signal to the second coil, wherein the second excitation signal is used to increase the duration of the platform zone.

[0005] The above solution enables the second coil to compensate for the excitation core when the duration of the platform area does not meet the preset duration requirement, thereby having obvious resistance to external magnetic field interference and obtaining more accurate measured current information.

[0006] In some embodiments, in response to the duration of the plateau region not meeting a preset duration requirement, before applying the second excitation signal to the second coil, the method further includes: determining the plateau region based on the amplitude of the detection signal. This solution effectively determines whether the duration of the plateau region of the detection signal meets the preset duration requirement, thereby enabling the second coil to compensate for the excitation core when the duration of the plateau region does not meet the preset duration requirement, thereby providing significant resistance to external magnetic field interference.

[0007] In some embodiments, determining the plateau region based on the amplitude of the detection signal includes dividing the detection signal into a plurality of consecutive time periods; and determining that the previous time period belongs to the plateau region in response to a difference between an average amplitude of a previous time period and an average amplitude of a next time period being within a preset difference range. The above solution effectively determines the plateau region.

[0008] In some embodiments, in response to the duration of the platform zone not meeting a preset duration requirement, applying a second excitation signal to the second coil includes: determining a duration ratio of the duration of the platform zone in the detection signal; and, in response to the duration ratio being less than or equal to a preset ratio threshold, determining that the duration of the platform zone does not meet the preset duration requirement. This solution effectively determines whether the duration of the platform zone meets the preset duration requirement, thereby facilitating effective determination of whether to apply the second excitation signal to the second coil to increase the platform zone.

[0009] In some embodiments, the detection signal includes a first half-cycle and a second half-cycle of opposite polarity, and the platform area includes a first platform area located within the first half-cycle and a second platform area located within the second half-cycle; determining the duration ratio of the duration of the platform area in the detection signal includes: taking the ratio of the duration of the first platform area to the duration of the first half-cycle, the ratio of the duration of the second platform area to the duration of the second half-cycle, or the ratio of the average duration of the first platform area and the second platform area to the average duration of the first half-cycle and the second half-cycle as the duration ratio. The above scheme effectively determines the duration ratio, thereby effectively determining whether the duration of the platform area meets the preset duration requirement, which is conducive to effectively determining whether to apply a second excitation signal to the second coil to increase the platform area.

[0010] In some embodiments, applying a second excitation signal to the second coil in response to the duration of the platform zone not meeting a preset duration requirement includes: determining that the duration of the platform zone does not meet the preset duration requirement in response to the duration of the platform zone being less than or equal to a preset duration threshold. This solution effectively determines whether the duration of the platform zone meets the preset duration requirement, thereby facilitating effective determination of whether to apply the second excitation signal to the second coil to increase the platform zone.

[0011] In some embodiments, in response to the duration of the platform region not meeting a preset duration requirement, applying the second excitation signal to the second coil includes: applying the second excitation signal to the second coil with a first polarity; and in response to the duration of the platform region decreasing, applying the second excitation signal to the second coil with a second polarity, wherein the first polarity and the second polarity are opposite. This scheme effectively controls the second coil, providing significant immunity to external magnetic field interference.

[0012] In some embodiments, in response to the duration of the plateau region not meeting a preset duration requirement, applying a second excitation signal to the second coil further includes: maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal in response to the duration of the plateau region increasing. This approach effectively controls the second coil, providing significant immunity to external magnetic field interference and obtaining more accurate measured current information.

[0013] In some embodiments, the control method further includes: in response to the duration of the plateau region meeting the duration requirement, calculating the measured current information based on the detection signal. The above solution obtains more accurate measured current information and improves the current sampling accuracy when subjected to external magnetic field interference.

[0014] In a second aspect, the present application provides a current sensor, comprising a control module, a magnetic core, a first coil and a second coil for exciting the magnetic core, a detection circuit, a first excitation module connected to the first coil, and a second excitation module connected to the second coil, wherein the control module is used to execute the control method in the above-mentioned first aspect.

[0015] The above solution enables the second coil to compensate for the excitation core when the duration of the platform area does not meet the preset duration requirement, thereby having obvious resistance to external magnetic field interference and obtaining more accurate measured current information.

[0016] In some embodiments, the detection circuit is connected to the first coil via the first excitation module to obtain the detection signal from the first coil. The above solution enables the detection signal to be obtained to detect whether it is affected by external magnetic field interference.

[0017] In some embodiments, the first excitation module is configured to apply the first excitation signal to the first coil, and the second excitation module is configured to apply the second excitation signal to the second coil, wherein the first excitation signal is an AC signal and the second excitation signal is a DC signal. The above scheme effectively controls the two coils.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The drawings herein are incorporated into the specification and constitute a part of this specification. These drawings illustrate embodiments consistent with the present application and are used together with the specification to illustrate the technical solutions of the present application.

[0020] Figure 1 is a flow chart of a method for controlling a current sensor according to some embodiments of the present application;

[0021] Figure 2 is a schematic structural diagram of a current sensor according to some embodiments of the present application;

[0022] Figure 3 is a schematic diagram of a voltage signal on a magnetic core of a current sensor according to some embodiments of the present application;

[0023] Figure 4 This is a partial flow chart of a method for controlling a current sensor according to some embodiments of the present application;

[0024] Figure 5 is a schematic structural diagram of a current sensor in some other embodiments of the present application;

[0025] Figure 6 Schematic diagram of voltage signals on the magnetic core of current sensors according to other embodiments of the present application. DETAILED DESCRIPTION

[0026] The following describes the embodiments of the present application in detail with reference to the accompanying drawings.

[0027] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0028] The term "and / or" in this article is simply a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects are in an "or" relationship. In addition, "many" in this article means two or more than two. In addition, the term "at least one" in this article means any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C can mean including any one or more elements selected from the set consisting of A, B, and C.

[0029] Currently, fluxgate current sensors utilize a single coil around the core, connected to an H-bridge. When used in BMS systems, these current sensors are susceptible to interference from external magnetic fields, impacting current sampling accuracy, due to the complex busbar structure within the high-voltage box and the harsh electromagnetic environment. Furthermore, to mitigate the effects of high-frequency external magnetic fields and fixed magnetic fields on the sensor, the primary approach is to add magnetic shielding materials to the mounting structure. However, this increases the sensor size, assembly complexity, and cost.

[0030] To this end, a first excitation signal is applied to the first coil to stimulate the alternating saturation of the magnetic core, and a detection signal is obtained from the magnetic core, wherein the detection signal includes multiple mutation zones corresponding to the magnetic core entering and exiting the saturation state and a platform zone located between two adjacent mutation zones. In response to the duration of the platform zone not meeting the preset duration requirement, a second excitation signal is applied to the second coil, wherein the second excitation signal is used to increase the duration of the platform zone, so that the second coil compensates for the excitation of the magnetic core when the duration of the platform zone does not meet the preset duration requirement, thereby having obvious resistance to external magnetic field interference and obtaining more accurate measured current information.

[0031] See also Figure 1 , Figure 1 : This is a flow chart of a control method for a current sensor in some embodiments of the present application, wherein the current sensor includes a magnetic core and a first coil and a second coil for exciting the magnetic core. The control method of the current sensor includes: step S11: applying a first excitation signal to the first coil to excite the magnetic core to alternate saturation. Step S12: acquiring a detection signal from the magnetic core, wherein the detection signal includes a plurality of mutation zones corresponding to the magnetic core entering and exiting a saturation state and a platform zone located between two adjacent mutation zones. Step S13: in response to the duration of the platform zone not meeting a preset duration requirement, applying a second excitation signal to the second coil, wherein the second excitation signal is used to increase the duration of the platform zone.

[0032] To facilitate understanding of the present application, the current sensor 20 according to the embodiment of the present application will be described below.

[0033] See also Figure 2 , Figure 22 is a schematic structural diagram of a current sensor according to some embodiments of the present application. The current sensor 20 includes a magnetic core 21, a first coil 22 and a second coil 23 for exciting the magnetic core 21, a control module 24, a detection circuit 25, a first excitation module 26 connected to the first coil 22, and a second excitation module 27 connected to the second coil 23. The detection circuit 25 is connected to the first coil 22 via the first excitation module 26 and is connected to the control module 24. The control module 24 is also connected to the first excitation module 26 and the second excitation module 27. The control module 24 can be a programmable MCU, etc. The magnetic core 21 can be made of a soft magnetic material with high magnetic permeability, such as permalloy, iron-based amorphous, iron-based nanocrystal, cobalt-based amorphous, etc. The first excitation module 26 and the second excitation module 27 can both be H-bridge excitation modules. The first excitation signal can be an AC signal, and the second excitation signal can be a DC signal.

[0034] Combine Figure 2 As shown, the control module 24 applies a first excitation signal to the first coil 22 through the first excitation module 26 to excite the magnetic core 21 to alternate saturation. The alternate saturation of the magnetic core 21 refers to the magnetic core 21 entering a saturated state and the magnetic core 21 exiting a saturated state. The magnetic core 21 entering a saturated state indicates that the voltage or current on the magnetic core 21 reaches a preset threshold. Figure 3 As shown, Figure 3 is a schematic diagram of a voltage signal on the magnetic core of a current sensor in some embodiments of the present application, wherein: Figure 3 Schematic diagram (a) shows the voltage signal when the measured primary current Ip is equal to 0, and schematic diagram (b) shows the voltage signal when the measured primary current Ip is not equal to 0. The mutation regions 31-36 correspond to the magnetic core 21 entering and exiting the saturation state. There is a platform region x31 between the mutation regions 31 and 32, and there is a platform region x32 between the mutation regions 33 and 34. Subsequently, the control module 24 obtains a detection signal from the magnetic core 21 through the detection circuit 25. The detection signal can be a voltage signal on the magnetic core 21, for example, Figure 3 When the duration of the platform area does not meet the preset duration requirement, the control module 24 applies a second excitation signal to the second coil 23 to increase the duration of the platform area, that is, by compensating the magnetic core 21 to increase the duration of the platform area in the detection signal obtained from the magnetic core 21.

[0035] The duration of the platform area in the detection signal does not meet the preset duration requirement, indicating that the current sensor 20 is greatly affected by the external magnetic field interference. The duration of the platform area meets the preset duration requirement, indicating that the current sensor 20 is less affected by the external magnetic field interference, or has no effect.

[0036] In the above scheme, a first excitation signal is applied to the first coil 22 to stimulate the magnetic core 21 to alternately saturate, and a detection signal is obtained from the magnetic core 21, wherein the detection signal includes a plurality of mutation zones corresponding to the magnetic core 21 entering and exiting the saturation state and a platform zone located between two adjacent mutation zones. In response to the duration of the platform zone not meeting the preset duration requirement, a second excitation signal is applied to the second coil 23, wherein the second excitation signal is used to increase the duration of the platform zone, so that the second coil 23 compensates for the excitation of the magnetic core 21 when the duration of the platform zone does not meet the preset duration requirement, thereby having obvious resistance to external magnetic field interference and obtaining more accurate measured current information.

[0037] In some embodiments, before step S13 , the method further includes: determining a platform area based on the amplitude of the detection signal.

[0038] The detection signal may be a voltage signal on the magnetic core 21, for example, Figure 3 , the amplitude of the detection signal is recorded as the voltage amplitude. Before applying the second excitation signal to the second coil 23, the plateau region can be determined based on the voltage amplitude of the detection signal, and then it can be determined whether the duration of the plateau region of the detection signal meets the preset duration requirement. If so, the second excitation signal is applied to the second coil 23 to increase the duration of the plateau region.

[0039] In the above scheme, by determining the platform area based on the amplitude of the detection signal, it is possible to determine whether the duration of the platform area of ​​the detection signal meets the preset duration requirement, thereby effectively determining whether the duration of the platform area of ​​the detection signal meets the preset duration requirement, and then achieving the second coil 23 compensating the excitation core 21 when the duration of the platform area does not meet the preset duration requirement, so as to have obvious resistance to external magnetic field interference.

[0040] In some embodiments, determining the platform area based on the amplitude of the detection signal includes the following steps: dividing the detection signal into a plurality of continuously set time periods; in response to the difference between the average amplitude of the previous time period and the average amplitude of the next time period being within a preset difference range, determining that the previous time period belongs to the platform area.

[0041] Multiple consecutively set time periods have the same and fixed duration, that is, the duration of each time period is the same and fixed, the previous time period and the next time period are adjacent time periods, and when the difference between the average amplitude of the previous time period and the average amplitude of the next time period is within the preset difference range, it can be determined that the previous time period belongs to the platform area. Figure 3For example, multiple consecutive time periods are set between the mutation zone 31 and the mutation zone 32. When the difference between the average voltage amplitude of the previous time period and the average voltage amplitude of the next time period is within a preset difference range, for example, the time period with a difference less than 10%, it can be judged that the previous time period belongs to the platform zone x31 and / or x32.

[0042] In the above solution, the platform area is effectively determined by dividing the detection signal into a plurality of consecutively set time periods and calculating whether the difference between the average amplitudes of the front and rear sections falls within a preset difference range.

[0043] In some embodiments, the duration of the platform area does not meet the preset duration requirement, including: determining the duration ratio of the platform area in the detection signal; in response to the duration ratio being less than a preset proportion threshold, determining that the duration of the platform area does not meet the preset duration requirement.

[0044] The duration of the platform area accounts for the duration of the detection signal, which can be the ratio of the duration of the platform area to the duration of the period of the detection signal. The preset ratio threshold can be designed according to actual conditions, for example, it can be 90%. When the duration ratio is less than or equal to the preset ratio threshold, for example, when the duration ratio is less than 90%, the duration of the platform area does not meet the preset duration requirement. On the contrary, when the duration ratio is greater than the preset ratio threshold, for example, when the duration ratio is greater than or equal to 90%, the duration of the platform area meets the preset duration requirement.

[0045] In the above scheme, by determining the proportion of the duration of the platform area in the detection signal, in response to the duration proportion being less than or equal to the preset proportional threshold, it is determined that the duration of the platform area does not meet the preset duration requirement, thereby effectively determining whether the duration of the platform area meets the preset duration requirement, which is conducive to effectively determining whether to apply a second excitation signal to the second coil 23 to increase the platform area.

[0046] In some embodiments, the detection signal includes a first half-cycle and a second half-cycle with opposite polarities, and the platform area includes a first platform area located in the first half-cycle and a second platform area located in the second half-cycle; determining the duration ratio of the platform area in the detection signal includes the following steps: taking the ratio between the duration of the first platform area and the duration of the first half-cycle, the ratio between the duration of the second platform area and the duration of the second half-cycle, or the ratio between the average duration of the first platform area and the second platform area and the average duration of the first half-cycle and the second half-cycle as the duration ratio.

[0047] The first half cycle and the second half cycle have opposite polarity, the first half cycle can be a positive cycle, the second half cycle can be a negative cycle, and there are platform areas in the first half cycle and the second half cycle, wherein the platform area in the first half cycle can be the first platform area, and the platform area in the second half cycle can be the second platform area. For determining the duration ratio, for example, the ratio between the duration of the first platform area and the duration of the first half cycle can be used as the duration ratio. For another example, the ratio between the duration of the second platform area and the duration of the second half cycle can be used as the duration ratio. For another example, the ratio between the average duration of the first platform area and the second platform area and the average duration of the first half cycle and the second half cycle can be used as the duration ratio. Figure 3 Taking diagram (b) as an example, t31 is the duration of the first half-cycle, corresponding to the positive cycle, and t32 is the duration of the second half-cycle, corresponding to the negative cycle. During t31, the voltage of the detection signal is positive, with a first plateau region x31, which lasts for p31. During t32, the voltage of the detection signal is negative, with a second plateau region x32, which lasts for p32. That is, the polarity of the detection signals corresponding to t31 and t32 is opposite. The duration ratio can be t31 / p31, t32 / p32, or (t31+t32) / (p31+p32).

[0048] In the above scheme, by taking the ratio of the duration of the first platform area to the duration of the first half cycle, the ratio of the duration of the second platform area to the duration of the second half cycle, or the ratio of the average duration of the first platform area and the second platform area to the average duration of the first half cycle and the second half cycle as the duration ratio, the duration ratio is effectively determined, thereby effectively determining whether the duration of the platform area meets the preset duration requirement, which is conducive to effectively determining whether to apply a second excitation signal to the second coil 23 to increase the platform area.

[0049] In some embodiments, the duration of the platform area does not meet the preset duration requirement, including: in response to the duration of the platform area being less than a preset duration threshold, determining that the duration of the platform area does not meet the preset duration requirement.

[0050] The preset duration threshold can be designed according to actual conditions. When the duration of the platform area is less than the preset duration threshold, the duration of the platform area does not meet the preset duration requirement. On the contrary, when the duration of the platform area is greater than or equal to the preset duration threshold, the duration of the platform area meets the preset duration requirement. Figure 3Taking schematic diagram (b) as an example, t31 is the duration of the first half-cycle, corresponding to the positive cycle, and t32 is the duration of the second half-cycle, corresponding to the negative cycle. During t31, the voltage of the detection signal is positive, with a first plateau region x31, whose duration is p31. During t32, the voltage of the detection signal is negative, with a second plateau region x32, whose duration is p32. That is, the polarity of the detection signals corresponding to t31 and t32 is opposite. For example, the duration p31 of the first plateau region x31 can be compared with a preset duration threshold to determine whether the duration p31 of the first plateau region x31 meets the preset duration requirement. For another example, the duration p32 of the second plateau region x32 can be compared with a preset duration threshold to determine whether the duration p32 of the second plateau region x32 meets the preset duration requirement. For another example, the sum of the duration p31 of the first platform area x31 and the duration p32 of the second platform area x32 can be compared with a preset duration threshold to determine whether the duration p31 of the first platform area x31 and the duration p32 of the second platform area x32 meet the preset duration requirement.

[0051] In the above scheme, when the duration of the platform area is less than the preset duration threshold, it is determined that the duration of the platform area does not meet the preset duration requirement, thereby effectively determining whether the duration of the platform area meets the preset duration requirement, which is conducive to effectively determining whether to apply the second excitation signal to the second coil 23 to increase the platform area.

[0052] In some embodiments, as Figure 4 As shown, Figure 4 This is a partial flow diagram of a control method for a current sensor according to some embodiments of the present application. In step S13, in response to the duration of the plateau region not meeting a preset duration requirement, a second excitation signal is applied to the second coil 23. The method includes: step S41: applying the second excitation signal to the second coil 23 with a first polarity. Step S42: in response to the duration of the plateau region decreasing, applying the second excitation signal to the second coil 23 with a second polarity and increasing the amplitude of the second excitation signal, wherein the first polarity and the second polarity are opposite.

[0053] The first polarity and the second polarity can be positive / negative polarity, for example, the first polarity can be positive polarity and the second polarity can be negative polarity, and their polarities are opposite. The control module 24 applies a second excitation signal to the second coil 23 with a first polarity, that is, applies a second excitation signal of a first polarity, for example, a second excitation signal of a positive polarity, to the second coil 23. The control module 24 applies a second excitation signal to the second coil 23 with a second polarity, that is, applies a second excitation signal of a second polarity, for example, a second excitation signal of a negative polarity, to the second coil 23. The second excitation signal can be a voltage signal, so that the second excitation signal of a positive polarity can be a positive polarity voltage signal, and the second excitation signal of a negative polarity can be a negative polarity voltage signal. The amplitude of the second excitation signal can be the amplitude of the voltage signal, that is, the voltage amplitude.

[0054] When the control module 24 applies a second excitation signal to the second coil 23 with positive polarity, if the duration of the platform area decreases, it indicates that the signal on the magnetic core 21 obtained by applying the positive polarity second excitation signal to the second coil 23 is opposite in polarity to the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the application of the positive polarity second excitation signal to the second coil 23 does not play a compensating role. At this time, the second excitation signal is applied to the second coil 23 with negative polarity, so that the signal on the magnetic core 21 obtained by applying the negative polarity second excitation signal to the second coil 23 is the same in polarity as the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the application of the negative polarity second excitation signal to the second coil 23 plays a compensating role, increases the amplitude of the second excitation signal, and thereby increases the duration of the platform area, so that the increased duration of the platform area meets the preset duration requirement.

[0055] Similarly, when the control module 24 applies a second excitation signal with negative polarity to the second coil 23, if the duration of the platform area decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with negative polarity to the second coil 23 is opposite in polarity to the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, applying the second excitation signal with negative polarity to the second coil 23 does not play a compensating role. At this time, the second excitation signal is applied to the second coil 23 with positive polarity, so that the signal on the magnetic core 21 obtained by applying the second excitation signal with positive polarity to the second coil 23 is the same in polarity as the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, applying the second excitation signal with negative polarity to the second coil 23 plays a compensating role, increasing the amplitude of the second excitation signal, thereby increasing the duration of the platform area, so that the increased duration of the platform area meets the preset duration requirement.

[0056] In the above scheme, by applying a second excitation signal to the second coil 23 with a first polarity, in response to a decrease in the duration of the platform area, applying a second excitation signal to the second coil 23 with a second polarity, and increasing the amplitude of the second excitation signal, the second coil 23 is effectively controlled, so that it has obvious resistance to external magnetic field interference.

[0057] In some embodiments, in step S13, in response to the duration of the platform area not meeting the preset duration requirement, applying a second excitation signal to the second coil 23, further comprising: in response to the duration of the platform area increasing, maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal.

[0058] When the control module 24 applies a second excitation signal to the second coil 23 with a first polarity, for example, applies a second excitation signal to the second coil 23 with a negative polarity, if the duration of the platform area increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the first polarity to the second coil 23 is the same as the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the second excitation signal of the first polarity applied to the second coil 23 plays a compensatory role. At this time, the current polarity of the second excitation signal, that is, the second excitation signal of the first polarity, is maintained, and the amplitude of the second excitation signal is increased, so that the duration of the platform area can be increased, so that the duration of the increased platform area meets the preset duration requirement.

[0059] Similarly, when the control module 24 applies a second excitation signal to the second coil 23 with a second polarity, for example, applies a second excitation signal to the second coil 23 with a positive polarity, if the duration of the platform area increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the second polarity to the second coil 23 is the same as the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the second excitation signal of the second polarity applied to the second coil 23 plays a compensatory role. At this time, the current polarity of the second excitation signal, that is, the second excitation signal of the second polarity, is maintained, and the amplitude of the second excitation signal is increased, so that the duration of the platform area can be increased, so that the duration of the increased platform area meets the preset duration requirement.

[0060] In the above scheme, by maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal when the duration of the platform area increases, the second coil 23 is effectively controlled, so that it has obvious resistance to external magnetic field interference and obtains more accurate current information to be measured.

[0061] In some embodiments, the control method further includes: in response to the duration of the platform area meeting the duration requirement, calculating the current information to be measured based on the detection signal.

[0062] If the duration of the plateau region meets the preset duration requirement, it indicates that the current sensor 20 is minimally or unaffected by the external magnetic field and has strong resistance to external magnetic fields. At this time, the measured current information is calculated based on the detection signal, i.e., the measured current information is measured. Because the current sensor 20 is minimally or unaffected by the external magnetic field, the measured current information is more accurate.

[0063] In the above solution, by calculating the measured current information based on the detection signal when the duration of the platform area meets the duration requirement, more accurate measured current information is obtained, thereby improving the current sampling accuracy when disturbed by the external magnetic field.

[0064] In some embodiments, as Figure 5 As shown, Figure 5 This is a structural schematic diagram of the current sensor of other embodiments of the present application. The current sensor 20 includes a control module 24, a magnetic core 21, a first coil 22 and a second coil 23 for exciting the magnetic core 21, a detection circuit 25, a first excitation module 26 connected to the first coil 22, a second excitation module 27 connected to the second coil 23, and a power supply module 28.

[0065] The detection circuit 25 may include a sampling resistor 251, connected to the first coil 22 through the first excitation module 26, and connected to the control module 24. The control module 24 is also connected to the first excitation module 26 and the second excitation module 27. The control module 24 may be a programmable MCU 241, which has an ADC module internally disposed therein, which detects the voltage waveform on the sampling resistor 251 as a detection signal. The magnetic core 21 may be made of a soft magnetic material with high magnetic permeability, such as permalloy, iron-based amorphous, iron-based nanocrystal, cobalt-based amorphous, etc. The first excitation module 26 and the second excitation module 27 may both be H-bridge excitation modules. The power supply module 28 is connected to the programmable MCU 241, the first excitation module 26, and the second excitation module 27, and is used to supply power to the programmable MCU 241, the first excitation module 26, and the second excitation module 27 to enable them to operate. The first excitation signal may be an AC signal, and the second excitation signal may be a DC signal.

[0066] The programmable MCU 241 outputs the PWM wave 1 to the first excitation module 26 . The first excitation module 26 applies a first excitation signal, ie, an AC signal, to the first coil 22 to excite the magnetic core 21 to alternate saturation. The AC signal may be an AC voltage signal.

[0067] Subsequently, the programmable MCU 241 obtains a detection signal from the magnetic core 21 through the sampling resistor 251 and the first excitation module 26. The detection signal may be a voltage signal on the magnetic core 21, for example, Figure 6 The voltage signal in can also be called fluxgate waveform. Figure 6 As shown, Figure 6 Schematic diagram of voltage signals on the magnetic core of current sensors according to other embodiments of the present application, wherein: Figure 6 Schematic diagrams (a) and (b) both represent the voltage signal when the primary current Ip to be measured is not equal to 0. In the mutation regions 61-66, the magnetic core 21 enters and exits the saturation state, that is, there is a platform region x61 between the mutation region 61 and the mutation region 62, and there is a platform region x62 between the mutation region 63 and the mutation region 64.

[0068] Then, the programmable MCU 241 determines the platform area based on the amplitude of the detection signal. Figure 6 As shown, the detection signal is divided into a plurality of continuously set time periods. Then, in response to the difference between the average amplitude of the previous time period and the average amplitude of the next time period being within a preset difference range, it is determined that the previous time period belongs to the platform area x61 and / or x62.

[0069] Subsequently, the programmable MCU 241 determines the duration ratio of the platform area in the detection signal. Specifically, when the duration ratio is less than or equal to the preset proportional threshold, for example, when the duration ratio is less than 90%, the duration of the platform area does not meet the preset duration requirement. On the contrary, when the duration ratio is greater than the preset proportional threshold, for example, when the duration ratio is greater than or equal to 90%, the duration of the platform area meets the preset duration requirement. Among them, the ratio between the duration of the first platform area and the duration of the first half cycle, the ratio between the duration of the second platform area and the duration of the second half cycle, or the ratio between the average duration of the first platform area and the second platform area and the average duration of the first half cycle and the second half cycle is used as the duration ratio. In Figure 6 In diagram (a), t61 is the duration of the first half-cycle, corresponding to the positive cycle, and t62 is the duration of the second half-cycle, corresponding to the negative cycle. During t61, the detection signal voltage is positive, with a first plateau region x61, which lasts for p61. During t62, the detection signal voltage is negative, with a second plateau region x62, which lasts for p62. That is, the detection signals corresponding to t61 and t62 have opposite polarities. The duration ratio can be t61 / p61, t62 / p62, or (t61+t62) / (p61+p62).

[0070] Alternatively, the programmable MCU 241 directly determines the duration of the platform area. For example, when the duration of the platform area is less than a preset duration threshold, the duration of the platform area does not meet the preset duration requirement. On the contrary, when the duration of the platform area is greater than or equal to the preset duration threshold, the duration of the platform area meets the preset duration requirement. Figure 6In schematic diagram (a), for example, the duration p61 of the first platform area x61 can be compared with a preset duration threshold to determine whether the duration p61 of the first platform area x61 meets the preset duration requirement. For another example, the duration p62 of the second platform area x62 can be compared with a preset duration threshold to determine whether the duration p62 of the second platform area x62 meets the preset duration requirement. For another example, the sum of the duration p61 of the first platform area x61 and the duration p62 of the second platform area x62 can be compared with a preset duration threshold to determine whether the duration p61 of the first platform area x61 and the duration p62 of the second platform area x62 meet the preset duration requirement.

[0071] Then, if Figure 6 As shown in the schematic diagram (a), when the duration of the platform area x61 and / or x62 does not meet the preset duration requirement, for example, the duration of the platform area x61 and / or x62 accounts for less than 90%, it indicates that the current sensor 20 is greatly affected by the interference of the external magnetic field. The programmable MCU 241 outputs PWM wave 2 to the second excitation module 27, and the second excitation module 27 applies a second excitation signal, that is, a DC signal, to the second coil 23 to increase the duration of the platform area x61 and / or x62.

[0072] Specifically, the programmable MCU 241 applies a second excitation signal to the second coil 23 with a first polarity, i.e., a second excitation signal of a first polarity, e.g., a second excitation signal of a positive polarity, to the second coil 23. The programmable MCU 241 applies a second excitation signal to the second coil 23 with a second polarity, i.e., a second excitation signal of a second polarity, e.g., a second excitation signal of a negative polarity, to the second coil 23. The second excitation signal may be a voltage signal, such that a positive second excitation signal may be a positive voltage signal, and a negative second excitation signal may be a negative voltage signal. The amplitude of the second excitation signal may be the amplitude of the voltage signal, i.e., the voltage amplitude.

[0073] When the programmable MCU 241 applies a second excitation signal with positive polarity to the second coil 23, if the duration of the platform area x61 and / or x62 decreases, it indicates that the polarity of the signal on the magnetic core 21 obtained by applying the positive polarity second excitation signal to the second coil 23 is opposite to the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the application of the positive polarity second excitation signal to the second coil 23 does not play a compensating role. At this time, the second excitation signal is applied to the second coil 23 with negative polarity, so that the polarity of the signal on the magnetic core 21 obtained by applying the negative polarity second excitation signal to the second coil 23 is the same as the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the application of the negative polarity second excitation signal to the second coil 23 plays a compensating role, increases the amplitude of the second excitation signal, and thereby increases the duration of the platform area x61 and / or x62, so that the duration of the increased platform area meets the preset duration requirement.

[0074] Similarly, when the programmable MCU 241 applies a second excitation signal with negative polarity to the second coil 23, if the duration of the platform area decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with negative polarity to the second coil 23 is opposite in polarity to the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, applying the second excitation signal with negative polarity to the second coil 23 does not play a compensating role. At this time, applying the second excitation signal with positive polarity to the second coil 23 makes the signal on the magnetic core 21 obtained by applying the second excitation signal with positive polarity to the second coil 23 have the same polarity as the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, applying the second excitation signal with negative polarity to the second coil 23 plays a compensating role, increases the amplitude of the second excitation signal, and thereby increases the duration of the platform area x61 and / or x62, so that the duration of the increased platform area meets the preset duration requirement.

[0075] Furthermore, when the programmable MCU 241 applies a second excitation signal to the second coil 23 with a first polarity, for example, applies a second excitation signal to the second coil 23 with a negative polarity, if the duration of the platform area increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the first polarity to the second coil 23 is the same as the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the second excitation signal of the first polarity applied to the second coil 23 plays a compensating role. At this time, the current polarity of the second excitation signal, that is, the second excitation signal of the first polarity, is maintained, and the amplitude of the second excitation signal is increased, so that the duration of the platform area can be increased, so that the duration of the increased platform area meets the preset duration requirement.

[0076] Similarly, when the programmable MCU 241 applies a second excitation signal to the second coil 23 with a second polarity, for example, applies a second excitation signal to the second coil 23 with a positive polarity, if the duration of the platform area increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the second polarity to the second coil 23 is the same as the polarity of the signal on the magnetic core 21 obtained by applying the first excitation signal to the first coil 22, that is, the second excitation signal of the second polarity applied to the second coil 23 plays a compensating role. At this time, the current polarity of the second excitation signal, that is, the second excitation signal of the second polarity, is maintained, and the amplitude of the second excitation signal is increased, so that the duration of the platform area x61 and / or x62 can be increased, so that the duration of the increased platform area meets the preset duration requirement.

[0077] Then, if Figure 6 As shown in the schematic diagram (b) in FIG, the programmable MCU 241 determines whether the duration of the added platform area meets the preset duration requirement, for example, the duration of the platform area x61' and / or x62' accounts for greater than or equal to 90%, wherein the method for determining whether the duration of the added platform area meets the preset duration requirement is the same as Figure 6 The method of determining whether the duration of the platform area shown in the schematic diagram (a) meets the preset duration requirement is the same or similar. For example, the programmable MCU 241 obtains the value of the magnetic core 21 through the sampling resistor 251 and the first excitation module 26. Figure 6 In the detection signal in schematic diagram (b), mutation regions 61-66 correspond to the magnetic core 21 entering and exiting the saturation state. Specifically, there is a plateau region x61' between mutation regions 61 and 62, and a plateau region x62' between mutation regions 63 and 64. Subsequently, the programmable MCU 241 divides the detection signal into a plurality of consecutive time periods. If the difference between the average amplitude of the previous time period and the average amplitude of the next time period falls within a preset difference range, the programmable MCU 241 determines that the previous time period belongs to the plateau region. Subsequently, the programmable MCU 241 determines the duration ratio of the plateau region to the duration ratio of the detection signal. Specifically, if the duration ratio is less than or equal to a preset threshold ratio, for example, less than 90%, the duration ratio of the plateau region does not meet the preset duration requirement. Conversely, if the duration ratio is greater than the preset threshold ratio, for example, greater than or equal to 90%, the duration ratio of the plateau region meets the preset duration requirement. The ratio between the duration of the first platform area and the duration of the first half cycle, the ratio between the duration of the second platform area and the duration of the second half cycle, or the ratio between the average duration of the first platform area and the second platform area and the average duration of the first half cycle and the second half cycle is used as the duration ratio. Figure 6In diagram (b), t61 is the duration of the first half-cycle, corresponding to the positive cycle, and t62 is the duration of the second half-cycle, corresponding to the negative cycle. During t61, the detection signal voltage is positive, with a first plateau region x61', which lasts for p61'. During t62, the detection signal voltage is negative, with a second plateau region x62', which lasts for p62'. That is, the detection signals corresponding to t61 and t62 have opposite polarities. The duration ratio can be t61 / p61', t62 / p62', or (t61+t62) / (p61'+p62').

[0078] Then, when the duration of the added platform area x61' and / or x62' meets the preset duration requirement, Figure 6 As shown in the schematic diagram (b) in FIG, the programmable MCU 241 calculates the current information to be measured based on the detection signal to achieve current measurement.

[0079] Furthermore, when the duration of the platform area meets the preset duration requirement, Figure 3 As shown in the diagram (b), the programmable MCU 241 directly calculates the current information to be measured based on the detection signal to achieve current measurement. In other words, the programmable MCU 241 directly determines whether the duration of the plateau region meets the preset duration requirement, and thus directly calculates the current information to be measured based on the detection signal to achieve current measurement.

[0080] Please refer to Table 1, which is a performance comparison of the current sensor 20 of the present application and the current sensor of the ordinary fluxgate in the related art. When the external magnetic field strength is 0Gs, the platform area period of the current sensor 20 of the present application and the current sensor of the ordinary fluxgate is 95%, which is greater than 90%. When the external magnetic field strength is 50Gs, the platform area period of the current sensor of the ordinary fluxgate is 87%, which no longer meets the normal acquisition requirements. When the external magnetic field strength is 100Gs, 150Gs, and 200Gs, the platform period ratio shows a nonlinear downward trend, and the rate of decline gradually increases. When the external magnetic field strength is 50Gs, the platform area period of the fluxgate current sensor 20 of the embodiment of the present application is 95%, which meets the normal acquisition requirements. When the external magnetic field strength is 100Gs, 150Gs, and 200Gs, although the platform period ratio shows a downward trend, when the external magnetic field strength is 200Gs, the platform period ratio is 90%, which still meets the normal acquisition requirements.

[0081] Table 1: Performance comparison of current sensor 20

[0082]

[0083] The present application also provides a current sensor 20, such as Figure 2 and Figure 5As shown, the current sensor 20 includes a magnetic core 21, a first coil 22 and a second coil 23 for exciting the magnetic core 21, a control module 24, a detection circuit 25, a first excitation module 26 connected to the first coil 22, and a second excitation module 27 connected to the second coil 23. The detection circuit 25 is connected to the first coil 22 via the first excitation module 26 and to the control module 24, which is further connected to the first excitation module 26 and the second excitation module 27. The control module 24 can be a programmable MCU 241, etc. The magnetic core 21 can be made of a soft magnetic material with high magnetic permeability, such as permalloy, iron-based amorphous, iron-based nanocrystal, cobalt-based amorphous, etc. The detection circuit 25 can include a sampling resistor 251. The first excitation module 26 and the second excitation module 27 can both be H-bridge excitation modules. The first excitation signal can be an AC signal, and the second excitation signal can be a DC signal.

[0084] Programmable MCU 241 outputs PWM wave 1 to first excitation module 26. First excitation module 26 applies a first excitation signal, namely an AC signal, to first coil 22 to excite magnetic core 21 into alternating saturation. The AC signal can be an AC voltage signal. Programmable MCU 241 outputs PWM wave 2 to second excitation module 27. Second excitation module 27 applies a second excitation signal, namely a DC signal, to second coil 23.

[0085] In the above scheme, a first excitation signal is applied to the first coil 22 to stimulate the magnetic core 21 to alternately saturate, and a detection signal is obtained from the magnetic core 21, wherein the detection signal includes a plurality of mutation zones corresponding to the magnetic core 21 entering and exiting the saturation state and a platform zone located between two adjacent mutation zones. In response to the duration of the platform zone not meeting the preset duration requirement, a second excitation signal is applied to the second coil 23, wherein the second excitation signal is used to increase the duration of the platform zone, so that the second coil 23 compensates for the excitation of the magnetic core 21 when the duration of the platform zone does not meet the preset duration requirement, thereby having obvious resistance to external magnetic field interference and obtaining more accurate measured current information.

[0086] In some embodiments, as Figure 2 As shown, the detection circuit 25 is connected to the first coil 22 via the first excitation module 26 , and is used to obtain a detection signal from the first coil 22 .

[0087] In the above solution, the detection circuit 25 is connected to the first coil 22 via the first excitation module 26 to obtain a detection signal from the first coil 22 to detect whether it is affected by external magnetic field interference.

[0088] In some embodiments, the first excitation module 26 is used to apply a first excitation signal to the first coil 22 , and the second excitation module 27 is used to apply a second excitation signal to the second coil 23 , wherein the first excitation signal is an AC signal and the second excitation signal is a DC signal.

[0089] The second excitation signal is a DC signal, wherein the DC signal includes forward and reverse DC signals. DC signals of different directions are suitable for situations where the duration of different platforms does not meet the duration requirements. When the DC signal has the same polarity as the half-cycle, the duration of the platform area can be increased. When the DC signal has a different polarity than the half-cycle, the duration of the platform area can be reduced. In the above scheme, the first excitation module 26 is used to apply the first excitation signal to the first coil 22, and the second excitation module 27 is used to apply the second excitation signal to the second coil 23. The first excitation signal is an AC signal and the second excitation signal is a DC signal, thereby achieving effective control of the two coils.

[0090] In some embodiments, the functions or modules included in the device provided by the embodiments of the present disclosure can be used to execute the method described in the above method embodiments. The specific implementation can refer to the description of the above method embodiments. For the sake of brevity, it will not be repeated here.

[0091] The above description of the various embodiments tends to emphasize the differences between the various embodiments. The same or similar aspects can be referenced with each other and will not be repeated herein for the sake of brevity.

[0092] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device implementation methods described above are only schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation. For example, units or components can be combined or integrated into another system, or some features can be ignored or not executed. In another image position, the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0093] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in either hardware or software functional units. If the integrated units are implemented as software functional units and sold or used as standalone products, they may be stored on a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the portion that contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product. This computer software product, stored on a storage medium, includes instructions for causing a computer device (such as a personal computer, server, or network device) or processor to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, removable hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

Claims

1. A method for controlling a current sensor, characterized in that: The current sensor includes a magnetic core and a first coil and a second coil for exciting the magnetic core, and the control method includes: Applying a first excitation signal to the first coil to excite the magnetic core into alternate saturation; Acquire a detection signal from the magnetic core, wherein the detection signal includes a plurality of mutation regions corresponding to the magnetic core entering and exiting a saturation state and a platform region located between two adjacent mutation regions; In response to the duration of the platform area not meeting a preset duration requirement, applying a second excitation signal to the second coil, wherein the second excitation signal is used to increase the duration of the platform area; In response to the duration of the platform region meeting the duration requirement, current information to be measured is calculated based on the detection signal.

2. The control method according to claim 1, wherein: Before applying the second excitation signal to the second coil in response to the duration of the platform area not meeting the preset duration requirement, the method further includes: The plateau region is determined based on the amplitude of the detection signal.

3. The control method according to claim 2, wherein: The determining the platform area based on the amplitude of the detection signal comprises: dividing the detection signal into a plurality of consecutively set time periods; In response to the difference between the average amplitude of the previous time period and the average amplitude of the next time period being within a preset difference range, it is determined that the previous time period belongs to the platform area.

4. The control method according to claim 1, wherein: The duration of the platform area does not meet the preset duration requirements, including: Determine the proportion of the duration of the platform area in the duration of the detection signal; In response to the duration ratio being less than a preset ratio threshold, it is determined that the duration of the platform area does not meet a preset duration requirement.

5. The control method according to claim 4, wherein: The detection signal includes a first half cycle and a second half cycle with opposite polarities, and the platform area includes a first platform area located in the first half cycle and a second platform area located in the second half cycle; Determining the proportion of the duration of the platform area in the detection signal includes: The ratio of the duration of the first platform area to the duration of the first half cycle, the ratio of the duration of the second platform area to the duration of the second half cycle, or the ratio of the average duration of the first platform area and the second platform area to the average duration of the first half cycle and the second half cycle is used as the duration ratio.

6. The control method according to claim 1, wherein: The duration of the platform area does not meet the preset duration requirements, including: In response to the duration of the platform area being less than a preset duration threshold, it is determined that the duration of the platform area does not meet a preset duration requirement.

7. The control method according to claim 1, wherein: In response to the duration of the platform area not meeting the preset duration requirement, applying the second excitation signal to the second coil includes: applying the second excitation signal to the second coil with a first polarity; In response to the duration of the plateau region being reduced, applying the second excitation signal to the second coil with a second polarity and increasing the amplitude of the second excitation signal, wherein the first polarity and the second polarity are opposite.

8. The control method according to claim 7, wherein: In response to the duration of the platform area not meeting a preset duration requirement, applying a second excitation signal to the second coil further includes: In response to the duration of the platform region increasing, the current polarity of the second excitation signal is maintained, and the amplitude of the second excitation signal is increased.

9. A current sensor, characterized in that: It includes a control module, a magnetic core, a first coil and a second coil for exciting the magnetic core, a detection circuit, a first excitation module connected to the first coil, and a second excitation module connected to the second coil, wherein the control module is used to execute the control method according to any one of claims 1 to 8.

10. The current sensor according to claim 9, wherein The detection circuit is connected to the first coil via the first excitation module, and is used to obtain the detection signal from the first coil.

11. The current sensor according to claim 9, wherein The first excitation module is used to apply the first excitation signal to the first coil, and the second excitation module is used to apply the second excitation signal to the second coil, wherein the first excitation signal is an AC signal and the second excitation signal is a DC signal.

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