Current sensor and control method thereof

Abstract

The invention discloses a current sensor and a control method thereof. The current sensor comprises a magnetic core, a first coil and a second coil, the first coil and the second coil are used for exciting the magnetic core, and the control method comprises the steps of applying a first excitation signal to the first coil to excite alternate saturation of the magnetic core; acquiring a detection signal from the magnetic core, wherein the detection signal comprises a plurality of abrupt change areas corresponding to the magnetic core entering and exiting a saturation state and a platform area located between two adjacent abrupt change areas; in response to the situation that the duration of the platform area does not meet the preset duration requirement, a second excitation signal is applied to the second coil, and the second excitation signal is used for increasing the duration of the platform area. According to the scheme, the device has obvious external magnetic field interference resistance, and more accurate to-be-measured current information is obtained.

Description

Technical Field

[0001] This application relates to the technical field of current measurement, and particularly to a current sensor and its control method. Background Art

[0002] Fluxgate current sensors, which adopt the fluxgate principle, have been widely used in many fields due to their advantages such as high sensitivity, good linearity, high resolution, and high accuracy. Among them, in a typical current sensor based on the fluxgate principle, the magnetic core is only wound with a group of coils connected to an H-bridge. After being excited by an alternating square wave, a self-excited oscillation fluxgate effect is generated for current measurement. When used in a BMS system, due to the complex structure of the busbar in the high-voltage box and the harsh electromagnetic environment in the BMS system, this fluxgate principle sensor is extremely vulnerable to external magnetic field interference, affecting the current sampling accuracy. Summary of the Invention

[0003] To solve the above problems, this application proposes a current sensor and its control method.

[0004] In a first aspect, this application provides a control method for a current sensor. 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 saturate alternately; obtaining a detection signal from the magnetic core, where the detection signal includes a plurality of mutation regions corresponding to the magnetic core entering and exiting the saturation state and a plateau region located between two adjacent mutation regions; in response to the duration of the plateau region not meeting a preset duration requirement, applying a second excitation signal to the second coil, where the second excitation signal is used to increase the duration of the plateau region.

[0005] The above solution realizes compensating and exciting the magnetic core by the second coil when the duration of the plateau region does not meet the preset duration requirement, thereby having an obvious anti-external magnetic field interference ability and obtaining more accurate information about the current to be measured.

[0006] In some embodiments, before applying the second excitation signal to the second coil in response to the duration of the plateau region not meeting the preset duration requirement, it further includes: determining the plateau region based on the amplitude of the detection signal. The above solution realizes effectively determining whether the duration of the plateau region of the detection signal meets the preset duration requirement, and further realizes compensating and exciting the magnetic core by the second coil when the duration of the plateau region does not meet the preset duration requirement, so as to have an obvious anti-external magnetic field interference ability.

[0007] In some embodiments, determining the platform region based on the amplitude of the detection signal includes: dividing the detection signal into a plurality of continuously arranged time periods; in response to the difference between the average amplitude of the previous time period and the average amplitude of the subsequent time period being within a preset difference range, determining that the previous time period belongs to the platform region. The above solution effectively determines the platform region. In some embodiments, in response to the duration of the platform region not meeting the preset duration requirement, applying a second excitation signal to the second coil includes: determining the duration ratio of the platform region in the detection signal; in response to the duration ratio being less than or equal to a preset ratio threshold, determining that the duration of the platform region does not meet the preset duration requirement. The above solution effectively determines whether the duration of the platform region meets the preset duration requirement, thereby facilitating the effective determination of whether to apply a second excitation signal to the second coil to increase the platform region. In some embodiments, the detection signal includes a first half-cycle and a second half-cycle with opposite polarities, and the platform region includes a first platform region within the first half-cycle and a second platform region within the second half-cycle; determining the duration ratio of the platform region in the detection signal includes: using the ratio of the duration of the first platform region to the duration of the first half-cycle, the ratio of the duration of the second platform region to the duration of the second half-cycle, or the ratio of the average duration of the first platform region and the second platform region to the average duration of the first half-cycle and the second half-cycle as the duration ratio. The above solution effectively determines the duration ratio, thereby effectively determining whether the duration of the platform region 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 region.

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

[0009] In some embodiments, the step of applying a second excitation signal to the second coil in response to the duration of the plateau region not meeting a preset duration requirement includes: applying the second excitation signal to the second coil with a first polarity; and in response to a decrease in the duration of the plateau region, applying the second excitation signal to the second coil with a second polarity, where the first polarity and the second polarity are opposite. The above solution effectively controls the second coil, resulting in an obvious ability to resist external magnetic field interference.

[0010] In some embodiments, the step of applying a second excitation signal to the second coil in response to the duration of the plateau region not meeting a preset duration requirement further includes: in response to an increase in the duration of the plateau region, maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal. The above solution effectively controls the second coil, resulting in an obvious ability to resist external magnetic field interference and obtaining more accurate information about the current to be measured.

[0011] In some embodiments, the control method further includes: in response to the duration of the plateau region meeting the duration requirement, calculating information about the current to be measured based on the detection signal. The above solution obtains more accurate information about the current to be measured and improves the current sampling accuracy when affected by external magnetic field interference.

[0012] In a second aspect, the present application provides a current sensor, including 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, where the control module is configured to execute the control method in the first aspect above.

[0013] The above solution realizes compensating and exciting the magnetic core by the second coil when the duration of the plateau region does not meet the preset duration requirement, thereby having an obvious ability to resist external magnetic field interference and obtaining more accurate information about the current to be measured.

[0014] In some embodiments, the detection circuit is connected to the first coil through the first excitation module and is configured to obtain the detection signal from the first coil. The above solution realizes obtaining the detection signal to detect whether it is affected by external magnetic field interference.

[0015] 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, where the first excitation signal is an alternating current signal and the second excitation signal is a direct current signal. The above solution realizes effective control of the two coils.

[0016] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit the present application. Description of the Drawings

[0017] The drawings herein are incorporated into and constitute a part of this specification. These drawings illustrate embodiments consistent with the present application and, together with the specification, are used to explain the technical solutions of the present application.

[0018] Figure 1 is a schematic flowchart of a control method for a current sensor according to some embodiments of the present application; Figure 2 is a schematic structural diagram of a current sensor according to some embodiments of the present application; 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; Figure 4 is a partial schematic flowchart of a control method for a current sensor according to some embodiments of the present application; Figure 5 is a schematic structural diagram of a current sensor according to some other embodiments of the present application; Figure 6 is a schematic diagram of a voltage signal on a magnetic core of a current sensor according to some other embodiments of the present application. Detailed Description of the Embodiments

[0019] The following describes the solutions of the embodiments of the present application in detail with reference to the drawings in the specification.

[0020] In the following description, specific details such as specific system architectures, interfaces, and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the present application.

[0021] The term "and / or" herein is merely a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after. Furthermore, "multiple" herein means two or more than two. In addition, the term "at least one" herein means any one of multiple or any combination of at least two of multiple. For example, including at least one of A, B, and C can represent including any one or more elements selected from the set composed of A, B, and C.

[0022] Currently, in a current sensor based on the fluxgate principle, only one set of coils is wound around the magnetic core and connected to the H-bridge. When used in a BMS system, due to the complex structure of the busbar in the high-voltage box and the harsh electromagnetic environment in the BMS system, this current sensor is extremely vulnerable to external magnetic field interference, affecting the current sampling accuracy. In addition, currently, in order to reduce the interference of high-frequency external magnetic fields and fixed magnetic fields on the sensor, it is mainly achieved by adding magnetic shielding materials to the installation structure, but this results in an increase in the volume of the sensor, more complex assembly, and higher costs.

[0023] Therefore, by applying a first excitation signal to the first coil to excite the magnetic core to saturate alternately, a detection signal is obtained from the magnetic core, where the detection signal includes multiple mutation regions corresponding to the magnetic core entering and exiting the saturation state and a plateau region located between two adjacent mutation regions. In response to the duration of the plateau region not meeting the preset duration requirement, a second excitation signal is applied to the second coil, where the second excitation signal is used to increase the duration of the plateau region, realizing that when the duration of the plateau region does not meet the preset duration requirement, the second coil compensates to excite the magnetic core, thereby having an obvious anti-external magnetic field interference ability and obtaining more accurate current information to be measured.

[0024] Please refer to Figure 1 , Figure 1 FIG. is a schematic flowchart of a control method for a current sensor according to some embodiments of the present application. 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: Apply a first excitation signal to the first coil to excite the magnetic core to saturate alternately. Step S12: Obtain a detection signal from the magnetic core, where the detection signal includes multiple mutation regions corresponding to the magnetic core entering and exiting the saturation state and a plateau region located between two adjacent mutation regions. Step S13: In response to the duration of the plateau region not meeting the preset duration requirement, apply a second excitation signal to the second coil, where the second excitation signal is used to increase the duration of the plateau region.

[0025] Next, for the convenience of understanding the present application, the current sensor 20 according to the embodiments of the present application will be described first.

[0026] Please refer to Figure 2 , Figure 2It 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 through 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 or the like. The magnetic core 21 can be prepared from a soft magnetic material with high magnetic permeability, and can include permalloy, iron-based amorphous, iron-based nanocrystalline, cobalt-based amorphous, etc. Both the first excitation module 26 and the second excitation module 27 can be H-bridge excitation modules. The first excitation signal can be an alternating current signal, and the second excitation signal can be a direct current signal.

[0027] Combined 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 saturate alternately. The magnetic core 21 saturating alternately means that the magnetic core 21 enters the saturation state and the magnetic core 21 exits the saturation state. When the magnetic core 21 enters the saturation state, it means that the voltage or current on the magnetic core 21 reaches a preset threshold. As Figure 3 shown, Figure 3 It is a schematic diagram of the voltage signal on the magnetic core of the current sensor according to some embodiments of the present application. Among them, Figure 3 the schematic diagram (a) in represents the voltage signal when the primary current Ip to be measured is equal to 0, and the schematic diagram (b) represents the voltage signal when the primary current Ip to be measured is not equal to 0. In the mutation regions 31 - 36, corresponding to the magnetic core 21 entering and exiting the saturation state, there is a plateau region x31 between the mutation regions 31 and 32, and there is a plateau 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 the voltage signal on the magnetic core 21. For example, Figure 3 the voltage signal in. When the duration of the plateau region 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 plateau region, that is, by compensating the magnetic core 21 to increase the duration of the plateau region in the detection signal obtained from the magnetic core 21.

[0028] That the duration of the plateau region in the detection signal does not meet the preset duration requirement indicates that the current sensor 20 is more affected by external magnetic field interference. That the duration of the plateau region meets the preset duration requirement indicates that the current sensor 20 is less affected by external magnetic field interference, or not affected.

[0029] In the above scheme, a first excitation signal is applied to the first coil 22 to excite 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 when the duration of the platform zone does not meet the preset duration requirement, the second coil 23 compensates for the excitation of the magnetic core 21, thereby having obvious resistance to external magnetic field interference and obtaining more accurate current information to be measured.

[0030] In some embodiments, before step S13, the method further includes: determining a platform area based on the amplitude of the detection signal.

[0031] The detection signal may be a voltage signal on the magnetic core 21, for example, Figure 3 Before applying the second excitation signal to the second coil 23, the platform area can be determined based on the voltage amplitude of the detection signal, and then it can be determined whether the duration of the platform area of ​​the detection signal meets the preset duration requirement, so that, if it meets the preset duration requirement, the second excitation signal is applied to the second coil 23 to increase the duration of the platform area.

[0032] 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.

[0033] 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.

[0034] 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, a plurality of consecutive time periods are set between the mutation region 31 and the mutation region 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, a time period with a difference less than 10%, it can be determined that the previous time period belongs to the platform region x31 and / or x32.

[0035] In the above solution, 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 segments belongs to a preset difference range, the platform region is effectively determined. In some embodiments, the duration of the platform region does not meet the preset duration requirement, including: determining the ratio of the duration of the platform region in the detection signal; in response to the ratio being less than a preset ratio threshold, determining that the duration of the platform region does not meet the preset duration requirement.

[0036] The ratio of the duration of the platform region in the detection signal can be the ratio of the duration of the platform region to the duration of the period of the detection signal. The preset ratio threshold can be designed according to the actual situation. For example, it can be 90%. When the ratio is less than or equal to the preset ratio threshold, for example, when the ratio is less than 90%, the duration of the platform region does not meet the preset duration requirement. On the contrary, when the ratio is greater than the preset ratio threshold, for example, when the ratio is greater than or equal to 90%, the duration of the platform region meets the preset duration requirement.

[0037] In the above solution, by determining the ratio of the duration of the platform region in the detection signal, and in response to the ratio being less than or equal to the preset ratio threshold, determining that the duration of the platform region does not meet the preset duration requirement, it is effectively determined whether the duration of the platform region meets the preset duration requirement, which is beneficial to effectively determining whether to apply a second excitation signal to the second coil 23 to increase the platform region.

[0038] In some embodiments, the detection signal includes a first half-cycle and a second half-cycle with opposite polarities, and the platform region includes a first platform region within the first half-cycle and a second platform region within the second half-cycle; determining the ratio of the duration of the platform region in the detection signal includes the following steps: using the ratio of the duration of the first platform region to the duration of the first half-cycle, the ratio of the duration of the second platform region to the duration of the second half-cycle, or the ratio of the average duration of the first platform region and the second platform region to the average duration of the first half-cycle and the second half-cycle as the ratio.

[0039] The first half-cycle and the second half-cycle have opposite polarities. The first half-cycle can be a positive cycle, and the second half-cycle can be a negative cycle. There are plateau regions in both the first half-cycle and the second half-cycle. The plateau region in the first half-cycle can be the first plateau region, and the plateau region in the second half-cycle can be the second plateau region. For determining the duration ratio, for example, the ratio between the duration of the first plateau region and the duration of the first half-cycle can be used as the duration ratio. Another example is that the ratio between the duration of the second plateau region and the duration of the second half-cycle can be used as the duration ratio. Still another example is that the ratio between the average duration of the first plateau region and the second plateau region and the average duration of the first half-cycle and the second half-cycle can be used as the duration ratio. Taking Figure 3 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. Among them, within t31, the voltage of the detection signal is positive, having the first plateau region x31 with a duration of p31. Within t32, the voltage of the detection signal is negative, having the second plateau region x32 with a duration of p32, that is, the polarities of the detection signals corresponding to t31 and t32 are opposite. The duration ratio can be t31 / p31, t32 / p32, or (t31 + t32) / (p31 + p32).

[0040] In the above solution, by using the ratio between the duration of the first plateau region and the duration of the first half-cycle, the ratio between the duration of the second plateau region and the duration of the second half-cycle, or the ratio between the average duration of the first plateau region and the second plateau region and 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 plateau region meets the preset duration requirement, which is beneficial to effectively determining whether to apply the second excitation signal to the second coil 23 to increase the plateau region.

[0041] In some embodiments, the duration of the plateau region does not meet the preset duration requirement, including: in response to the duration of the plateau region being less than the preset duration threshold, it is determined that the duration of the plateau region does not meet the preset duration requirement.

[0042] The preset duration threshold can be designed according to the actual situation. When the duration of the plateau region is less than the preset duration threshold, the duration of the plateau region does not meet the preset duration requirement. On the contrary, when the duration of the plateau region is greater than or equal to the preset duration threshold, the duration of the plateau region meets the preset duration requirement. Taking Figure 3Taking the 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. Among them, within t31, the voltage of the detection signal is positive, having a first platform region x31 with a duration of p31. Within t32, the voltage of the detection signal is negative, having a second platform region x32 with a duration of p32. That is, the polarities of the detection signals corresponding to t31 and t32 are opposite. For example, the duration p31 of the first platform region x31 can be compared with a preset duration threshold to determine whether the duration p31 of the first platform region x31 meets the preset duration requirement. Another example is that the duration p32 of the second platform region x32 can be compared with a preset duration threshold to determine whether the duration p32 of the second platform region x32 meets the preset duration requirement. Still another example is that the sum of the duration p31 of the first platform region x31 and the duration p32 of the second platform region x32 can be compared with a preset duration threshold to determine whether the duration p31 of the first platform region x31 and the duration p32 of the second platform region x32 meet the preset duration requirement.

[0043] In the above solution, when the duration of the platform region is less than the preset duration threshold, it is determined that the duration of the platform region does not meet the preset duration requirement, effectively determining whether the duration of the platform region meets the preset duration requirement, which is beneficial to effectively determining whether to apply the second excitation signal to the second coil 23 to increase the platform region.

[0044] In some embodiments, as Figure 4 shown, Figure 4 is a partial flowchart of the control method of the current sensor according to some embodiments of the present application. In step S13, in response to the duration of the platform region not meeting the preset duration requirement, applying a second excitation signal to the second coil 23 includes: step S41: applying a second excitation signal to the second coil 23 with a first polarity. Step S42: In response to the decrease in the duration of the platform region, applying a second excitation signal to the second coil 23 with a second polarity and increasing the amplitude of the second excitation signal, where the first polarity and the second polarity are opposite.

[0045] The first polarity and the second polarity can be positive / negative polarities. For example, the first polarity can be the positive polarity and the second polarity can be the negative polarity, with opposite polarities. The control module 24 applies a second excitation signal to the second coil 23 with the first polarity, that is, applies a second excitation signal of the first polarity to the second coil 23. For example, a second excitation signal of the positive polarity. The control module 24 applies a second excitation signal to the second coil 23 with the second polarity, that is, applies a second excitation signal of the second polarity to the second coil 23. For example, a second excitation signal of the negative polarity. Among them, the second excitation signal can be a voltage signal. Thus, the second excitation signal of the positive polarity can be a voltage signal of the positive polarity, and the second excitation signal of the negative polarity can be a voltage signal of the negative polarity. The amplitude of the second excitation signal can be the amplitude of the voltage signal, that is, the voltage amplitude.

[0046] When the control module 24 applies a second excitation signal to the second coil 23 with the positive polarity, if the duration of the plateau region decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the positive 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 of the positive polarity to the second coil 23 does not play a compensating role. At this time, apply a second excitation signal to the second coil 23 with the negative polarity, so that the signal on the magnetic core 21 obtained by applying the second excitation signal of the negative 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 of the negative polarity to the second coil 23 plays a compensating role. Increase the amplitude of the second excitation signal, thereby increasing the duration of the plateau region, so that the increased duration of the plateau region meets the preset duration requirement.

[0047] Similarly, when the control module 24 applies a second excitation signal to the second coil 23 with the negative polarity, if the duration of the plateau region decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal of the 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 of the negative polarity to the second coil 23 does not play a compensating role. At this time, apply a second excitation signal to the second coil 23 with the positive polarity, so that the signal on the magnetic core 21 obtained by applying the second excitation signal of the 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 of the negative polarity to the second coil 23 plays a compensating role. Increase the amplitude of the second excitation signal, thereby increasing the duration of the plateau region, so that the increased duration of the plateau region meets the preset duration requirement.

[0048] In the above solution, 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 plateau region, applying the 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, such that it has an obvious ability to resist external magnetic field interference.

[0049] In some embodiments, in step S13, when applying the second excitation signal to the second coil 23 in response to the duration of the plateau region not meeting the preset duration requirement, it further includes: in response to an increase in the duration of the plateau region, maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal.

[0050] When the control module 24 applies the second excitation signal to the second coil 23 with a first polarity, for example, applying the second excitation signal to the second coil 23 with a negative polarity, if the duration of the plateau region increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with the first polarity to the second coil 23 has 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 the first polarity to the second coil 23 plays a compensating role. At this time, maintaining the current polarity of the second excitation signal, that is, the second excitation signal with the first polarity, and increasing the amplitude of the second excitation signal, thereby the duration of the plateau region can be increased, such that the increased duration of the plateau region meets the preset duration requirement.

[0051] Similarly, when the control module 24 applies the second excitation signal to the second coil 23 with a second polarity, for example, applying the second excitation signal to the second coil 23 with a positive polarity, if the duration of the plateau region increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with the second polarity to the second coil 23 has 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 the second polarity to the second coil 23 plays a compensating role. At this time, maintaining the current polarity of the second excitation signal, that is, the second excitation signal with the second polarity, and increasing the amplitude of the second excitation signal, thereby the duration of the plateau region can be increased, such that the increased duration of the plateau region meets the preset duration requirement.

[0052] In the above solution, by maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal when the duration of the plateau region increases, the second coil 23 is effectively controlled, such that it has an obvious ability to resist external magnetic field interference and more accurate information about the current to be measured is obtained.

[0053] In some embodiments, the control method further includes: in response to the duration of the plateau region meeting the duration requirement, calculating the information about the current to be measured based on the detection signal.

[0054] 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 influence, and has a strong ability to resist the external magnetic field. At this time, the current information to be measured is calculated based on the detection signal, that is, the current information to be measured is measured. Since the current sensor 20 is less affected by the external magnetic field interference, or has no influence, the current information to be measured is more accurate.

[0055] In the above scheme, when the duration of the platform area meets the duration requirement, the current information to be measured is calculated based on the detection signal to obtain more accurate current information to be measured, thereby improving the current sampling accuracy when disturbed by the external magnetic field.

[0056] In some embodiments, Figure 5 As shown, Figure 5 It 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.

[0057] 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, and 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, and the programmable MCU 241 is internally provided with an ADC module, which detects the voltage waveform on the sampling resistor 251 as a detection signal. The magnetic core 21 may be prepared from a soft magnetic material with high magnetic permeability, and may include permalloy, iron-based amorphous, iron-based nanocrystalline, 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 work. The first excitation signal may be an AC signal, and the second excitation signal may be a DC signal.

[0058] 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.

[0059] Then, 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 is a schematic diagram of the voltage signal on the magnetic core of the current sensor in some other embodiments of the present application, where Figure 6 in 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, corresponding to the magnetic core 21 entering and exiting the saturation state, that is, there is a plateau region x61 between mutation region 61 and mutation region 62, and there is a plateau region x62 between mutation region 63 and mutation region 64.

[0060] Subsequently, the programmable MCU 241 determines the plateau region based on the amplitude of the detection signal. Specifically, as Figure 6 shown, the detection signal is divided into multiple consecutive time periods. Then, in response to the difference between the average amplitude of the previous time period and the average amplitude of the subsequent time period being within a preset difference range, it is determined that the previous time period belongs to the plateau region x61 and / or x62.

[0061] Subsequently, the programmable MCU 241 determines the duration ratio of the plateau region in the detection signal. Specifically, when the duration ratio is less than or equal to a preset ratio threshold, for example, when the duration ratio is less than 90%, the duration of the plateau region 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 plateau region meets the preset duration requirement. Among them, the ratio of the duration of the first plateau region to the duration of the first half - cycle, the ratio of the duration of the second plateau region to the duration of the second half - cycle, or the ratio of the average duration of the first plateau region and the second plateau region to the average duration of the first half - cycle and the second half - cycle is used as the duration ratio. In Figure 6 schematic diagram (a), t61 is the duration of the first half - cycle, corresponding to the positive cycle, t62 is the duration of the second half - cycle, corresponding to the negative cycle. Among them, within t61, the voltage of the detection signal is positive, having the first plateau region x61 with a duration of p61. Within t62, the voltage of the detection signal is negative, having the second plateau region x62 with a duration of p62, that is, the polarities of the detection signals corresponding to t61 and t62 are opposite. The duration ratio can be t61 / p61, t62 / p62, or (t61 + t62) / (p61 + p62).

[0062] Alternatively, the programmable MCU 241 directly determines the duration of the plateau region. For example, when the duration of the plateau region is less than a preset duration threshold, the duration of the plateau region does not meet the preset duration requirement. On the contrary, when the duration of the plateau region is greater than or equal to the preset duration threshold, the duration of the plateau region meets the preset duration requirement. In Figure 6In the schematic diagram (a), for example, the duration p61 of the first platform region x61 can be compared with a preset duration threshold to determine whether the duration p61 of the first platform region x61 meets the preset duration requirement. For another example, the duration p62 of the second platform region x62 can be compared with a preset duration threshold to determine whether the duration p62 of the second platform region x62 meets the preset duration requirement. For still another example, the sum of the duration p61 of the first platform region x61 and the duration p62 of the second platform region x62 can be compared with a preset duration threshold to determine whether the duration p61 of the first platform region x61 and the duration p62 of the second platform region x62 meet the preset duration requirement.

[0063] Subsequently, as Figure 6 shown in the schematic diagram (a) in [reference], when the duration of the platform region x61 and / or x62 does not meet the preset duration requirement, for example, the duration ratio of the platform region x61 and / or x62 is less than 90%, it indicates that the current sensor 20 is greatly affected by the external magnetic field interference. The programmable MCU 241 outputs the 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 region x61 and / or x62.

[0064] Specifically, the programmable MCU 241 applies the second excitation signal to the second coil 23 with a first polarity, that is, applies the second excitation signal with the first polarity to the second coil 23. For example, the second excitation signal with a positive polarity. The programmable MCU 241 applies the second excitation signal to the second coil 23 with a second polarity, that is, applies the second excitation signal with the second polarity to the second coil 23. For example, the second excitation signal with a negative polarity. Wherein, the second excitation signal can be a voltage signal. Thus, the second excitation signal with a positive polarity can be a positive-polarity voltage signal, and the second excitation signal with 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.

[0065] When the programmable MCU 241 applies a second excitation signal to the second coil 23 with a positive polarity, if the duration of the platform region x61 and / or x62 decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with a positive polarity to the second coil 23 has the opposite 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 a positive polarity to the second coil 23 does not play a compensating role. At this time, apply the second excitation signal to the second coil 23 with a negative polarity, so that the signal on the magnetic core 21 obtained by applying the second excitation signal with a negative polarity to the second coil 23 has 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 a negative polarity to the second coil 23 plays a compensating role. Increase the amplitude of the second excitation signal, thereby increasing the duration of the platform region x61 and / or x62, so that the increased duration of the platform region meets the preset duration requirement.

[0066] Similarly, when the programmable MCU 241 applies a second excitation signal to the second coil 23 with a negative polarity, if the duration of the platform region decreases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with a negative polarity to the second coil 23 has the opposite 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 a negative polarity to the second coil 23 does not play a compensating role. At this time, apply the second excitation signal to the second coil 23 with a positive polarity, so that the signal on the magnetic core 21 obtained by applying the second excitation signal with a positive polarity to the second coil 23 has 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 a negative polarity to the second coil 23 plays a compensating role. Increase the amplitude of the second excitation signal, thereby increasing the duration of the platform region x61 and / or x62, so that the increased duration of the platform region meets the preset duration requirement.

[0067] Further, when the programmable MCU 241 applies a second excitation signal to the second coil 23 with a first polarity, for example, applies the second excitation signal to the second coil 23 with a negative polarity, if the duration of the platform region increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with the first polarity to the second coil 23 has 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 the first polarity to the second coil 23 plays a compensating role. At this time, maintain the current polarity of the second excitation signal, that is, the second excitation signal with the first polarity, and increase the amplitude of the second excitation signal, thereby increasing the duration of the platform region, so that the increased duration of the platform region meets the preset duration requirement.

[0068] Similarly, when the programmable MCU 241 applies a second excitation signal to the second coil 23 with a second polarity, for example, applies the second excitation signal to the second coil 23 with a positive polarity, if the duration of the plateau region increases, it indicates that the signal on the magnetic core 21 obtained by applying the second excitation signal with the second polarity to the second coil 23 has 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 the second polarity to the second coil 23 plays a compensating role. At this time, maintain the current polarity of the second excitation signal, that is, the second excitation signal with the second polarity, and increase the amplitude of the second excitation signal, thereby increasing the duration of the plateau region x61 and / or x62, so that the increased duration of the plateau region meets the preset duration requirement.

[0069] Subsequently, as shown in Figure 6 schematic diagram (b) therein, the programmable MCU 241 determines that the increased duration of the plateau region meets the preset duration requirement. For example, the duration ratio of the plateau region x61' and / or x62' is greater than or equal to 90%. Among them, the determination method of whether the increased duration of the plateau region meets the preset duration requirement is the same as or similar to the determination method of whether the duration of the plateau region shown in Figure 6 schematic diagram (a) therein meets the preset duration requirement. For example, the programmable MCU 241 obtains the Figure 6 detection signal in schematic diagram (b) therein through the sampling resistor 251 and the first excitation module 26. In the mutation regions 61 - 66, corresponding to the magnetic core 21 entering and exiting the saturation state, that is, there is a plateau region x61' between the mutation region 61 and the mutation region 62, and there is a plateau region x62' between the mutation region 63 and the mutation region 64. Subsequently, the programmable MCU 241 divides the detection signal into multiple 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, it is determined that the previous time period belongs to the plateau region. Subsequently, the programmable MCU 241 determines the duration ratio of the plateau region in the detection signal. Specifically, 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 plateau region 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 plateau region meets the preset duration requirement. Among them, the ratio of the duration of the first plateau region to the duration of the first half cycle, the ratio of the duration of the second plateau region to the duration of the second half cycle, or the ratio of the average duration of the first plateau region and the second plateau region to the average duration of the first half cycle and the second half cycle is used as the duration ratio. In Figure 6In the schematic 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. Among them, within t61, the voltage of the detection signal is positive, having a first platform region x61’ with a duration of p61’. Within t62, the voltage of the detection signal is negative, having a second platform region x62’ with a duration of p62’. That is, the polarities of the detection signals corresponding to t61 and t62 are opposite. The duration ratios can be t61 / p61’, t62 / p62’ or (t61 + t62) / (p61’ + p62’).

[0070] Subsequently, when the duration of the increased platform region x61’ and / or x62’ meets the preset duration requirement, as shown in the schematic diagram (b) in Figure 6 the programmable MCU 241 calculates the current information to be measured based on the detection signal to achieve current measurement.

[0071] Furthermore, when the duration of the platform region meets the preset duration requirement, as shown in the schematic diagram (b) in Figure 3 the programmable MCU 241 directly calculates the current information to be measured based on the detection signal to achieve current measurement. That is to say, the programmable MCU 241 directly determines that the duration of the platform region meets the preset duration requirement, thereby directly calculating the current information to be measured based on the detection signal to achieve current measurement.

[0072] Please refer to Table 1 for the performance comparison between 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 0 Gs, the platform region cycle ratio of the current sensor 20 of the present application and the current sensor of the ordinary fluxgate is both 95%, which is greater than 90%. When the external magnetic field strength is 50 Gs, the platform region cycle ratio of the current sensor of the ordinary fluxgate is 87%, which no longer meets the normal acquisition requirements. And when the external magnetic field strengths are 100 Gs, 150 Gs, and 200 Gs respectively, the platform cycle ratio shows a non-linear downward trend, and the downward speed gradually increases. While when the external magnetic field strength is 50 Gs, the platform region cycle ratio of the fluxgate current sensor 20 in the embodiment of the present application is 95%, which meets the normal acquisition requirements. When the external magnetic field strengths are 100 Gs, 150 Gs, and 200 Gs respectively, although the platform cycle ratio shows a downward trend, when the external magnetic field strength is 200 Gs, the platform cycle ratio is 90%, still meeting the normal acquisition requirements.

[0073] Table 1: Performance comparison of current sensor 20

[0074] The present application also provides a current sensor 20, as shown in Figure 2 and Figure 5As shown in the figure, 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 through 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 241, etc. The magnetic core 21 can be prepared from a soft magnetic material with high magnetic permeability, and can include permalloy, iron-based amorphous, iron-based nanocrystalline, cobalt-based amorphous, etc. The detection circuit 25 can include a sampling resistor 251. Both the first excitation module 26 and the second excitation module 27 can be H-bridge excitation modules. The first excitation signal can be an AC signal, and the second excitation signal can be a DC signal.

[0075] The programmable MCU 241 outputs a PWM wave 1 to the first excitation module 26. The first excitation module 26 applies a first excitation signal, that is, an AC signal, to the first coil 22 to excite the magnetic core 21 to saturate alternately. The AC signal can be an AC voltage signal. The programmable MCU 241 outputs a PWM wave 2 to the second excitation module 27. The second excitation module 27 applies a second excitation signal, that is, a DC signal, to the second coil 23.

[0076] In the above solution, by applying a first excitation signal to the first coil 22 to excite the magnetic core 21 to saturate alternately, a detection signal is obtained from the magnetic core 21. The detection signal includes a plurality of mutation regions corresponding to the magnetic core 21 entering and exiting the saturation state and a platform region between two adjacent mutation regions. In response to the duration of the platform region not meeting the preset duration requirement, a second excitation signal is applied to the second coil 23. The second excitation signal is used to increase the duration of the platform region, so as to realize that when the duration of the platform region does not meet the preset duration requirement, the second coil 23 compensates to excite the magnetic core 21, thereby having an obvious anti-external magnetic field interference ability and obtaining more accurate current information to be measured.

[0077] In some embodiments, as Figure 2 shown, the detection circuit 25 is connected to the first coil 22 through the first excitation module 26 and is used to obtain a detection signal from the first coil 22.

[0078] In the above solution, the detection circuit 25 is connected to the first coil 22 through the first excitation module 26 and is used to obtain a detection signal from the first coil 22, so as to obtain a detection signal to detect whether it is affected by external magnetic field interference.

[0079] In some embodiments, the first excitation module 26 is configured to apply a first excitation signal to the first coil 22, and the second excitation module 27 is configured to apply a second excitation signal to the second coil 23, wherein the first excitation signal is an alternating current signal and the second excitation signal is a direct current signal.

[0080] The second excitation signal is a direct current signal. Among them, the direct current signal includes positive and negative direct current signals. Different directions of direct current signals are applicable to the cases where the duration of different platforms does not meet the duration requirements. When the direct current signal is the same as the polarity of the half cycle, the duration of the platform area can be increased, and when the direct current signal is different from the polarity of the half cycle, the duration of the platform area is reduced. In the above solution, 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 alternating current signal and the second excitation signal is a direct current signal, so as to achieve effective control of the two coils.

[0081] In some embodiments, the functions or modules included in the device provided in the embodiments of the present disclosure can be used to execute the methods described in the method embodiments above. The specific implementation can refer to the description of the method embodiments above. For the sake of brevity, it will not be described in detail here.

[0082] The descriptions of the above embodiments tend to emphasize the differences between the embodiments. The same or similar parts can be referred to each other. For the sake of brevity, they will not be described in detail in this article.

[0083] In several embodiments provided in the present application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of modules or units is only a logical function division. In actual implementation, there may be other division methods. 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 displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of the device or unit can be in electrical, mechanical or other forms.

[0084] In addition, each functional unit in various embodiments of the present application may be integrated into one processing unit, or each unit may exist physically alone, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of a software functional unit. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, may be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods in various embodiments of the present application. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical discs that can store program codes.

Claims

1. A control method for a current sensor, characterized in that, The current sensor includes a magnetic core, 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 saturate alternately; Obtaining a detection signal from the magnetic core, where the detection signal includes a plurality of mutation regions corresponding to the magnetic core entering and exiting the saturation state and a plateau region located between two adjacent mutation regions; In response to the duration of the plateau region not meeting a preset duration requirement, applying a second excitation signal to the second coil, where the second excitation signal is used to increase the duration of the plateau region.

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 plateau region not meeting the preset duration requirement, it further includes: Determining the plateau region based on the amplitude of the detection signal.

3. The control method according to claim 2, characterized in that, The determining the plateau region based on the amplitude of the detection signal includes: Dividing the detection signal into a plurality of continuously arranged time periods; If the difference between the average amplitude of the previous time period and the average amplitude of the next time period is within a preset difference range, determining that the previous time period belongs to the plateau region.

4. The control method according to claim 1, wherein The duration of the plateau region not meeting the preset duration requirement includes: Determining the proportion of the duration of the plateau region in the duration of the detection signal; If the proportion is less than a preset proportion threshold, determining that the duration of the plateau region does not meet the preset duration requirement.

5. The control method according to claim 4, characterized in that, The detection signal includes a first half-cycle and a second half-cycle with opposite polarities. The plateau region includes a first plateau region within the first half-cycle and a second plateau region within the second half-cycle; The determining the proportion of the duration of the plateau region in the duration of the detection signal includes: Taking the ratio of the duration of the first plateau region to the duration of the first half-cycle, the ratio of the duration of the second plateau region to the duration of the second half-cycle, or the ratio of the average duration of the first plateau region and the second plateau region to the average duration of the first half-cycle and the second half-cycle as the proportion.

6. The control method according to claim 1, wherein The duration of the plateau region not meeting the preset duration requirement includes: If the duration of the plateau region is less than a preset duration threshold, determining that the duration of the plateau region does not meet the preset duration requirement.

7. The control method according to claim 1, characterized in that, Applying the second excitation signal to the second coil in response to the duration of the plateau region not meeting the preset duration requirement includes: Applying the second excitation signal to the second coil with a first polarity; If the duration of the plateau region decreases, applying the second excitation signal to the second coil with a second polarity opposite to the first polarity and increasing the amplitude of the second excitation signal.

8. The control method according to claim 7, wherein Applying the second excitation signal to the second coil in response to the duration of the plateau region not meeting the preset duration requirement further includes: If the duration of the plateau region increases, maintaining the current polarity of the second excitation signal and increasing the amplitude of the second excitation signal.

9. The control method according to claim 1, characterized in that, The control method further includes: In response to the duration of the platform region meeting the duration requirement, calculate the current information to be measured based on the detection signal.

10. 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 1-9.

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

12. The current sensor according to claim 10, characterized in that 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 alternating current signal and the second excitation signal is a direct current signal.

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