Fluxgate type current sensor, control method and device thereof, wind generating set and storage medium

Abstract

The invention provides a fluxgate type current sensor and a control method and device thereof, a wind generating set and a storage medium, the fluxgate type current sensor comprises a driving circuit, a power supply, a driving switch and a processor, the driving circuit is used for outputting an excitation signal to realize current detection, and the driving switch is connected between the driving circuit and the power supply. The control method comprises the following steps: in response to power-on of a power supply, executing an open-loop mode so as to control a drive circuit to output a preset excitation signal and control the drive switch to be closed; acquiring a current detection signal during execution of the open-loop mode; under the condition that the current detection signal shows that the detected circuit is not powered on, the driving switch is kept closed, and a closed-loop mode is executed, so that the driving circuit outputs an excitation signal based on the feedback signal; and when the current detection signal indicates that the detected circuit is powered on, the driving switch is switched off. According to the invention, the damage risk of the fluxgate type current sensor can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of current detection, and more particularly, to a fluxgate current sensor, a control method and device thereof, a wind turbine generator, and a storage medium. BACKGROUND

[0002] The existing current sensors are usually Hall type and electromagnetic type. The Hall type is easily damaged by temperature and is difficult to be applied in high temperature environment, so the electromagnetic type is usually used in high temperature environment. However, the electromagnetic type can only detect alternating current and cannot detect direct current, which causes a technical difficulty in how to effectively detect current in high temperature environment.

[0003] At present, there is also a current sensor using fluxgate effect in the industry, but the application is less. And the existing fluxgate current sensor can detect alternating current and direct current in high temperature environment, but it is very easy to be damaged, and has the defects of low reliability and difficult maintenance. SUMMARY

[0004] Therefore, how to reduce the damage risk of the fluxgate current sensor is crucial for effectively detecting current in high temperature environment.

[0005] In one general aspect, there is provided a control method of a fluxgate current sensor for detecting current of a measured circuit using fluxgate effect, the fluxgate current sensor comprising a drive circuit, a power supply, a drive switch and a processor, the drive circuit being configured to output an excitation signal to realize current detection, the drive switch being connected between the drive circuit and the power supply, the drive switch being in a default off state, the processor being connected to an input of the drive circuit and the drive switch, the processor being configured to execute the control method, the control method comprising: in response to power-on of the power supply, executing an open-loop mode to control the drive circuit to output a preset excitation signal and control the drive switch to be closed; during execution of the open-loop mode, acquiring a current detection signal; in a case where the current detection signal indicates that the measured circuit is not powered on, keeping the drive switch closed and executing a closed-loop mode to enable the drive circuit to output an excitation signal based on a feedback signal; and in a case where the current detection signal indicates that the measured circuit is powered on, turning off the drive switch.

[0006] Optionally, the magnetic flux gate current sensor further comprises a waveform generator and a signal switching circuit, wherein the waveform generator is configured to output a first driving signal based on the feedback signal, the first driving signal being configured to control the driving circuit to output the excitation signal, the processor is configured to output a second driving signal in the open loop mode, the second driving signal being configured to control the driving circuit to output the preset excitation signal, an input end of the signal switching circuit is connected to an output end of the waveform generator and the processor, a priority of the first driving signal is lower than a priority of the second driving signal, and an output end of the signal switching circuit is connected to an input end of the driving circuit.

[0007] Optionally, the control method further comprises: obtaining a signal related to the feedback signal as a reference signal during execution of the closed loop mode; and controlling the driving circuit to stop outputting the excitation signal in a case where the reference signal satisfies a preset abnormal condition.

[0008] Optionally, the reference signal comprises the feedback signal, and the preset abnormal condition comprises at least one of the following: the feedback signal is 0, or the feedback signal is not twice the frequency of the excitation signal; or the reference signal comprises a first driving signal output by a waveform generator of the magnetic flux gate current sensor based on the feedback signal, and the preset abnormal condition comprises at least one of the following: the first driving signal remains unchanged, or a frequency of the first driving signal is not equal to a frequency of the excitation signal.

[0009] Optionally, the control of the driving circuit to stop outputting the excitation signal comprises: turning off the driving switch; and / or the magnetic flux gate current sensor further comprises a protection circuit connected between an input end of the driving circuit and the processor, and the control of the driving circuit to stop outputting the excitation signal comprises: controlling the protection circuit to output a protection signal with a value of 0 to the driving circuit, so that the driving circuit stops outputting the excitation signal.

[0010] Optionally, the control method further comprises: outputting an alarm information in a case where the reference signal satisfies a preset abnormal condition.

[0011] In another general aspect, a fluxgate current sensor is provided, comprising: a drive circuit for outputting an excitation signal to achieve current detection; a power supply; a drive switch connected between the drive circuit and the power supply, the drive switch being in an off state by default; a processor connected to the input terminal of the drive circuit and the drive switch; and at least one memory storing computer-executable instructions connected to the processor, wherein the computer-executable instructions, when executed by the processor, cause the processor to execute the control method of the fluxgate current sensor as described above.

[0012] In another general aspect, a wind turbine generator set is provided, the wind turbine generator set comprising: a circuit under test; and a fluxgate current sensor as described above, the fluxgate current sensor being used to detect current in the circuit under test.

[0013] Optionally, the circuit under test includes an IGBT circuit, and the fluxgate current sensor is used to detect the output current of the IGBT circuit.

[0014] In another general aspect, a computer-readable storage medium is provided, wherein when instructions in the computer-readable storage medium are executed by at least one processor, the at least one processor causes the at least one processor to perform the control method of the fluxgate current sensor as described above.

[0015] This disclosure provides a fluxgate current sensor and its control method, device, wind turbine generator set, and storage medium. By adding a drive switch that is defaulted to being disconnected between the drive circuit and the power supply of the existing fluxgate current sensor, the drive circuit can be kept in an unpowered state by default, avoiding incorrect power-on timing when the power supply is first turned on, thereby achieving the purpose of protecting the drive circuit 102 when powered on. At the same time, after the fluxgate current sensor is powered on, an open-loop mode is first adopted and the drive switch is closed, so that the drive circuit can output a stable and safe preset excitation signal without being affected by feedback signals to test whether the circuit under test is powered on. Based on this, it is determined whether to disconnect the drive switch to reduce damage or switch to closed-loop mode to perform conventional current detection. That is, in the early stage of startup, the high-risk closed-loop mode is directly abandoned and replaced with a safe and reliable switching mode. Without the need for tedious analysis of the many influencing factors in the closed-loop mode, the damage risk of the fluxgate current sensor can be effectively reduced, its reliability improved, maintenance difficulty reduced, and the usage requirements of the fluxgate current sensor lowered.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0017] Figure 1 This is a topology diagram illustrating a fluxgate current sensor of a related technology;

[0018] Figure 2 This is a schematic diagram illustrating the current generated by the excitation coil of the related technology and the received excitation signal in the absence of the measured current;

[0019] Figure 3 This is a schematic diagram showing the waveforms of the current generated by the excitation coil and the received excitation signal in the absence of the measured current in the related technology.

[0020] Figure 4 This is a schematic diagram illustrating the current generated by the excitation coil of the related technology and the received excitation signal in the presence of the measured current;

[0021] Figure 5 This is a waveform diagram illustrating the current generated by the excitation coil and the received excitation signal in the presence of the measured current in the related technology.

[0022] Figure 6 This is a waveform diagram showing the current generated by the excitation coil of the related technology in the presence of the measured current, the received excitation signal, and the feedback signal of the fluxgate coil.

[0023] Figure 7 This is a topology diagram illustrating a fluxgate current sensor according to an embodiment of the present disclosure;

[0024] Figure 8 This is a flowchart illustrating a control method for a fluxgate current sensor according to an embodiment of the present disclosure;

[0025] Figure 9 This is a schematic flowchart illustrating a control method for a fluxgate current sensor according to a specific embodiment of the present disclosure.

[0026] Figure 1 Explanation of icon numbers:

[0027] 101': Power supply; 102': Drive circuit; 103': Excitation coil; 104': Fluxgate coil; 105': Flux detection circuit; 106': Filter circuit; 107': Waveform generator; 108': Sampling circuit; 1081': Sampling resistor; 1082': Operational amplifier; 109': Output circuit; 110': Magnetic core;

[0028] Figure 7 Explanation of icon numbers:

[0029] 101: Power supply; 102: Drive circuit; 107: Waveform generator; 111: Drive switch; 112: Processor; 113: Signal switching circuit; 114: Protection circuit. Detailed Implementation

[0030] The following detailed embodiments are provided to aid the reader in gaining a comprehensive understanding of the methods, apparatus, and / or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatus, and / or systems described herein will become apparent upon understanding this disclosure. For example, the order of operations described herein is merely illustrative and is not limited to those orders set forth herein, but may be changed as will become clear upon understanding this disclosure, except for operations that must occur in a specific order. Furthermore, for clarity and conciseness, descriptions of features known in the art may be omitted.

[0031] The features described herein may be implemented in different forms and should not be construed as limited to the examples described herein. Rather, the examples described herein are provided only to illustrate some of the many feasible ways of implementing the methods, apparatus, and / or systems described herein, which will become clear upon understanding the disclosure of this application.

[0032] As used herein, the term “and / or” includes any one of the associated listed items and any combination of any two or more.

[0033] Although terms such as “first,” “second,” and “third” may be used herein to describe various components, assemblies, regions, layers, or parts, these components, assemblies, regions, layers, or parts should not be limited by these terms. Rather, these terms are used only to distinguish one component, assembly, region, layer, or part from another. Thus, without departing from the teaching of the examples described herein, the first component, first assembly, first region, first layer, or first part referred to as the first component, first assembly, first region, first layer, or first part may also be referred to as the second component, second assembly, second region, second layer, or second part.

[0034] In the specification, when an element (such as a layer, region, or substrate) is described as being "on" another element, "connected to," or "bonded to" another element, the element may be directly "on" another element, directly "connected to," or "bonded to" the other element, or one or more other elements may be present in between. Conversely, when an element is described as being "directly on" another element, "directly connected to," or "directly bonded to" another element, no other elements may be present in between.

[0035] The terminology used herein is for the purpose of describing various examples only and is not intended to limit disclosure. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. The terms “comprising,” “including,” and “having” indicate the presence of the described features, quantities, operations, components, elements, and / or combinations thereof, but do not preclude the presence or addition of one or more other features, quantities, operations, components, elements, and / or combinations thereof.

[0036] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains upon understanding this disclosure. Unless expressly defined herein, terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and shall not be interpreted in an idealized or overly formalistic manner.

[0037] Furthermore, in the description of the examples, detailed descriptions of well-known related structures or functions will be omitted when it is believed that such detailed descriptions would lead to a vague interpretation of this disclosure.

[0038] A fluxgate current sensor is a high-precision current measurement device based on the fluxgate effect. Existing fluxgate current sensors have circuit topologies such as... Figure 1 As shown, its main structural components include a power supply 101' (which can be represented as VCC power supply), a drive circuit 102', an excitation coil 103', a fluxgate coil 104', a flux detection circuit 105', a filter circuit 106', a waveform generator 107', a sampling circuit 108', and an output circuit 109'. The drive circuit 102', for example, is an H-bridge drive circuit, used to output an excitation signal to the excitation coil 103'. Under normal circumstances, the excitation signal is an alternating high and low level signal, causing the magnetic core 110' to be repeatedly magnetized until it reaches saturation. The fluxgate coil 104' will be induced by the surrounding magnetic field (in the absence of the measured current I). P The alternating magnetic field generated by the excitation coil 103' is only the excitation magnetic field, and the measured current I is present. PThe induced current is generated by changes in the measured magnetic field. The flux detection circuit 105' detects the induced current or voltage generated by the fluxgate coil 104' as a feedback signal. The filter circuit 106' performs high-frequency filtering on the feedback signal. The waveform generator 107' generates alternating square wave signals with variable frequency and duty cycle based on the filtered and integrated signal, serving as the drive signal for the input drive circuit 102'. This causes the drive circuit 102' to output an excitation signal, which has the same frequency and voltage as the control signal but a larger current. This changes the square wave period and duty cycle of the excitation signal applied to the excitation coil 103', resulting in the final magnetic flux generated by the excitation coil 103' being exactly equal in magnitude and direction to the magnetic flux generated by the measured circuit. At this point, the magnetic flux in the magnetic core 110' is close to zero, and the induced current or voltage induced on the fluxgate coil 104' is also close to zero. Therefore, the measured current I can be obtained by detecting the excitation coil 103'. P The sampling circuit 108' includes a sampling resistor 1081' and an operational amplifier 1082' (abbreviated as op-amp). The sampling resistor 1081' is connected in series with the drive circuit 102' and the excitation coil 103'. The sampling circuit 108' and the output circuit 109' together form the signal output section. The amplitude of the output signal will be related to the measured current I. P The current detection is directly proportional to the feedback signal, achieving a closed-loop mode. Here, the closed-loop mode refers to determining the control signal of the input drive circuit 102' based on the feedback signal, and the current detection refers to determining the measured current I using the output signal obtained from the detection excitation coil 103'. P .

[0039] Specifically, regarding the detection principle, such as Figure 2 As shown, when there is no external current generating the measured magnetic field, i.e., when there is no current in the measured circuit, the fluxgate coil 104' will only be induced by the excitation alternating magnetic field generated by the excitation coil 103'. The waveform of the current i(t) generated by the excitation coil 103' changing with time can be found in the following diagram. Figure 3 The excitation coil 103' is a high-saturation coil. Driven by the excitation signal v(t), the current i(t) generated by the excitation coil 103' gradually accumulates and increases. After reaching saturation, it rises rapidly. Once it reaches the preset current threshold, it triggers the drive circuit 102' to flip the excitation signal v(t), for example, from a high-level signal to a low-level signal, or from a low-level signal to a high-level signal, causing the current i(t) to instantly return to 0 and continue to accumulate in the opposite direction. This process repeats until saturation is reached. At this time, the positive and negative half-cycles of the current i(t) are symmetrical, and the feedback signal output by the fluxgate coil 104' contains only the odd harmonics of the excitation waveform, and the waveform is symmetrical in both positive and negative directions.

[0040] When there is a DC external magnetic field being measured, that is, when there is a DC current I in the measured current. P At that time, the measured DC magnetic field and the excitation alternating magnetic field exist simultaneously in the magnetic core 110', for example... Figure 4 As shown, the measured current I P The generated DC magnetic field is aligned with the positive direction of the current i(t), causing the current i(t) to... Figure 5 As shown, the upward offset (or downward offset when the direction is opposite) causes the measured DC magnetic field to cause the excitation alternating magnetic field to saturate the magnetic core 110' prematurely in the first half of the cycle, while delaying the saturation of the magnetic core 110' in the other half of the cycle, thus causing asymmetry between the positive and negative half cycles in the excitation cycle. Figure 5 (This is for illustrative purposes only and does not show the asymmetry of the positive and negative half-cycles. Furthermore, the period will vary during actual operation and will not remain fixed.) The waveform of the feedback signal obtained from the fluxgate coil 104' at this point can be referenced. Figure 6 The curve shown resembles a sine curve (and) Figure 5 Similarly, Figure 6 (This is for illustrative purposes only). The feedback signal is twice the frequency of the excitation coil current / voltage signal. When there is no measured current, the feedback signal curve is a sine curve, i.e., symmetrical in both positive and negative half-cycles. When the measured current I is present... P The positive and negative half-cycles of the feedback signal are no longer symmetrical, resulting in an amplitude difference, and when the measured current I... P As the current increases, the amplitude difference of the feedback signal also increases. This amplitude difference is related to the measured current I. P The generated magnetic field is proportional to the amplitude difference, therefore the current I passing through the toroidal magnetic core 110' can be detected using the amplitude difference. P When the current being measured is alternating current, since the frequency of the excitation signal is in the hundreds of kHz range, while that of alternating current is only a few kHz or even tens of Hz, the alternating current can be considered as being composed of several direct currents when detecting alternating current. Therefore, the detection principle is the same as that for direct current.

[0041] Observations revealed that damage to existing fluxgate current sensors often occurs in the drive circuit 102'. Furthermore, if the circuit under test is powered on before the drive circuit 102', the drive circuit 102' is prone to damage or malfunction. Accordingly, existing fluxgate current sensors require strict control of the power-on sequence: the fluxgate current sensor must be powered on first (powering on the drive circuit 102'), and then the circuit under test must be powered on. Therefore, in scenarios where the power-on sequence is automatically controlled using microcontrollers or other electronic components, the risk of damage can be significantly reduced due to the strict control of the power-on sequence. However, in scenarios where the power-on sequence needs to be manually controlled, the risk of damage is very high.

[0042] Analysis suggests that the damage or abnormality occurring due to incorrect power-on timing is likely caused by the fluxgate current sensor operating in closed-loop mode. In this mode, numerous factors can influence the operation, such as the measured current I being powered on first by the circuit under test. P The presence of this will cause the zero point of the current i(t) to be inaccurate, while the measured current I P If the current is too large or exceeds the preset current threshold, the excitation signal will fail to flip. Furthermore, due to the extremely fast response speed in closed-loop mode (cycle time on the order of microseconds), the current i(t) of the drive circuit 102' will rapidly and continuously increase, causing damage. Additionally, the components used to compare i(t) and the current threshold may exhibit lag when using the circuit's output current threshold, resulting in a lower current threshold, which will also cause the excitation signal to fail to flip. These complex influencing factors can easily lead to abnormal feedback signals, causing poor driving of the drive circuit 102', and ultimately damaging both the drive circuit 102' and the sampling circuit 108'.

[0043] Based on the above analysis, the implementation of this disclosure is as follows: Figure 7 As shown, based on the existing fluxgate current sensor, by adding a drive switch 111 that is defaulted to being disconnected between the drive circuit 102 and the power supply 101, the drive circuit 102 can be kept in a state of not being powered on by default, avoiding incorrect power-on timing when the power supply 101 is first powered on, thereby achieving the purpose of protecting the drive circuit 102 when powered on. Meanwhile, according to the control method of the embodiments of this disclosure, after the fluxgate current sensor is powered on, an open-loop mode is first adopted and the drive switch 111 is closed, so that the drive circuit 102 can output a stable and safe preset excitation signal without being affected by feedback signals, to test whether the circuit under test is powered on. Based on this, it is then determined whether to disconnect the drive switch 111 to reduce damage, or switch to a closed-loop mode to perform conventional current detection. That is, in the early stage of startup, the higher-risk closed-loop mode is directly abandoned, and a safe and reliable open-loop mode is used instead. This eliminates the need for tedious analysis of the numerous influencing factors in the closed-loop mode, effectively reducing the damage risk of the fluxgate current sensor, improving its reliability, reducing maintenance difficulty, and lowering the usage requirements of the fluxgate current sensor.

[0044] Figure 8 This is a flowchart illustrating a control method for a fluxgate current sensor according to an embodiment of the present disclosure, specifically executed by a processor 112 in the fluxgate current sensor. It should be noted that, since the following text primarily describes the control flow, for ease of reading, structural components of the fluxgate current sensor will not be labeled.

[0045] Reference Figure 8 In step S801, in response to the power supply being turned on, the open-loop mode is executed to control the drive circuit to output a preset excitation signal and control the drive switch to close.

[0046] It should be understood that the power source here refers to... Figure 7 The power supply 101 is used in this circuit. When the power supply is powered on, by executing the open-loop mode and closing the drive switch, the drive circuit can operate based on a stable preset excitation signal. Optionally, the preset excitation signal is a square wave signal with a fixed preset frequency and preset duty cycle, and the duration of the preset excitation signal can also be a pre-set preset duration, thereby executing the preset duration open-loop mode to perform a brief test on whether the circuit under test is powered on.

[0047] As an example, for a drive switch that is in the off state by default, a normally open switch or a regular switch can be used, and the processor can control the drive switch to be in the off state by default. The drive switch can be a mechanical relay, or it can be an IGBT, MOSFET, power transistor, or other similar device. This disclosure does not limit the specific form of the drive switch.

[0048] Optionally, in step S801, the system is first set to open-loop mode to control the drive circuit to output a preset excitation signal, and then the drive switch is closed. This avoids directly running the conventional closed-loop mode after the drive switch is closed, thus fully ensuring that the fluxgate current sensor operates in open-loop mode.

[0049] In step S802, a current detection signal is acquired during the execution of open-loop mode.

[0050] In step S803, when the current detection signal indicates that the circuit under test is not powered on, the drive switch is kept closed and the closed-loop mode is executed so that the drive circuit outputs an excitation signal based on the feedback signal.

[0051] It should be understood that if the circuit under test is not powered on during the open-loop mode, the acquired current detection signal will show that the measured current is always 0. Therefore, the current detection signal can be used to determine whether the circuit under test is powered on. If the determination result is that the circuit is not powered on, it means that the power-on timing is correct, and the drive switch can be kept closed, switching from the open-loop mode to the normal closed-loop mode to achieve current detection.

[0052] In step S804, when the current detection signal indicates that the circuit under test is powered on, the drive switch is disconnected.

[0053] It should be understood that the purpose of executing open-loop mode is only to detect whether the circuit under test is powered on, not to detect the specific current in the circuit under test. Therefore, as long as the current detection signal shows that the measured current is not 0, it can be considered that the circuit under test is powered on, which can meet the test purpose. If the judgment result is that it is powered on, it means that the circuit under test is powered on in advance. By disconnecting the drive switch, an incorrect power-on sequence can be avoided, thereby reducing the risk of damage.

[0054] Regarding the implementation of switching between open-loop and closed-loop modes, for ease of explanation, we first define a first drive signal and a second drive signal. The first drive signal is output by the waveform generator based on the feedback signal and is used to control the drive circuit to output the excitation signal, equivalent to... Figure 1 The drive signal output by the waveform generator 107' in the related technology shown corresponds to the closed-loop mode. The second drive signal is output by the processor in the open-loop mode to control the drive circuit to output a preset excitation signal, corresponding to the open-loop mode.

[0055] In some embodiments, the output of the waveform generator is optionally connected to the processor. In open-loop mode, the processor ignores the first drive signal received from the waveform generator and outputs the second drive signal on its own. In closed-loop mode, the processor outputs the first drive signal received from the waveform generator, thereby realizing the switching between open-loop mode and closed-loop mode.

[0056] In other embodiments, optionally, such as Figure 7 As shown, the fluxgate current sensor also includes a signal switching circuit 113. The output of the signal switching circuit 113 is connected to the input of the drive circuit 102. The input of the signal switching circuit 113 is connected to the output of the waveform generator 107 and the processor 112. The priority of the first drive signal is lower than that of the second drive signal. This means that when the processor 112 executes open-loop mode and outputs the second drive signal, the signal switching circuit 113 will output the second drive signal accordingly. When the processor 112 executes closed-loop mode and does not output the second drive signal, the signal switching circuit 113 will output the first drive signal, which has a lower priority. In this embodiment, the processor 112 only needs to determine whether to output the second drive signal based on whether to execute open-loop mode, without interfering with the first drive signal. This simplifies the control logic of the processor 112, allowing the original working mode of the fluxgate current sensor to be basically maintained in closed-loop mode. This reduces interference with the original fluxgate current sensor and helps ensure the stable operation of the fluxgate current sensor.

[0057] Furthermore, during the execution of the conventional closed-loop mode for current detection, abnormal situations may sometimes occur, causing the drive circuit to be damaged or malfunction due to output errors. For example, the fluxgate coil may experience a loose connection due to vibration, resulting in the inability to detect the feedback signal. The waveform generator will then be unable to generate a valid first drive signal; specifically, the first drive signal may remain at a high or low level, causing the drive circuit to stop toggling the high and low level signals. Alternatively, an internal breakpoint in the drive circuit may directly prevent it from toggling the high and low level signals. Both of these situations will cause the current i(t) to exceed the current threshold and continue to increase, damaging the drive circuit and sampling circuit. If other abnormalities occur that cause the frequency of the first drive signal generated by the waveform generator in the input drive circuit to change (i.e., lose resonance), the feedback signal will no longer be twice the frequency of the excitation coil current / voltage signal; that is, the frequency of the first drive signal output by the waveform generator will no longer be equal to the frequency of the excitation coil current / voltage signal.

[0058] To address anomalies occurring during the operation of a fluxgate current sensor, the control method according to embodiments of this disclosure may optionally further include: during closed-loop mode execution, acquiring a signal related to the feedback signal as a reference signal. It should be understood that the output terminal of the circuit outputting the reference signal needs to be connected to a processor to acquire the reference signal; and, if the reference signal satisfies a preset anomaly condition, controlling the drive circuit to stop outputting the excitation signal. By combining the reference signal related to the feedback signal with the corresponding preset anomaly condition, anomalies that may occur during normal operation of the fluxgate current sensor can be detected. Furthermore, when an anomaly occurs, controlling the drive circuit to stop outputting the excitation signal, i.e., stopping current detection, provides protection and further ensures safe operation.

[0059] It should be understood that if it is determined that the reference signal does not meet the preset abnormal conditions, the current detection will continue to be performed, and the reference signal will continue to be acquired and monitored to see if the reference signal meets the preset abnormal conditions.

[0060] Regarding the reference signal and corresponding preset abnormal conditions, in some embodiments, the reference signal may optionally include a feedback signal, that is, the feedback signal is directly used as the reference signal. In this case, the processor is connected to the magnetic flux detection circuit to obtain its output feedback signal. The preset abnormal conditions include at least one of the following: the feedback signal is 0, or the feedback signal is not a harmonic of the excitation signal. Based on the foregoing analysis, when an abnormality exists, the feedback signal may be in two states: equal to 0 (undetectable) or no longer a harmonic of the excitation signal. By directly using the feedback signal as the reference signal and using these two abnormal states of the feedback signal as preset abnormal conditions, reliable detection of abnormal states can be achieved. It should be understood that "the feedback signal is not a harmonic of the excitation signal" here includes the allowance for small errors. That is, when the frequency of the feedback signal differs from twice the frequency of the excitation signal only within the error range, the feedback signal is considered to be a harmonic of the excitation signal; when the difference between the frequency of the feedback signal and twice the frequency of the excitation signal exceeds the error range, the feedback signal is considered not to be a harmonic of the excitation signal.

[0061] In some other embodiments, optionally, the reference signal includes a first drive signal output by the waveform generator of the fluxgate current sensor based on a feedback signal, such as... Figure 7 As shown, the processor is connected to the waveform generator to obtain its output first drive signal. The preset abnormal conditions include at least one of the following: the first drive signal remains unchanged, or the frequency of the first drive signal is not equal to the frequency of the excitation signal. Based on the foregoing analysis, when an abnormality exists, the first drive signal may remain at a high / low level without flipping, or its frequency may no longer be equal to the frequency of the excitation signal. By using the first drive signal as a reference signal and taking these two abnormal states of the first drive signal as preset abnormal conditions, reliable detection of abnormal states can be achieved. It should be understood that "not equal to" here includes the allowance for small errors; that is, when the frequency of the first drive signal and the frequency of the excitation signal differ only within the error range, they are considered equal; when the difference between the frequency of the first drive signal and the frequency of the excitation signal exceeds the error range, they are considered unequal.

[0062] As an example, either of the two reference signals mentioned above, namely the feedback signal and the first drive signal, can be used, or they can be used simultaneously in the form of "and" or "or", and corresponding preset abnormal conditions can be configured accordingly. This disclosure does not impose any restrictions on this.

[0063] Regarding how to control the drive circuit to stop outputting the excitation signal, in some embodiments, the operation optionally includes: disconnecting the drive switch. By directly disconnecting the drive switch, the drive circuit can be de-energized, causing it to stop working.

[0064] In other embodiments, optionally, such asFigure 7 As shown, the fluxgate current sensor also includes a protection circuit 114, which is connected between the input terminal of the drive circuit 102 and the processor 112. Controlling the drive circuit to stop outputting the excitation signal includes controlling the protection circuit to output a protection signal with a value of 0 to the drive circuit, thereby stopping the drive circuit from outputting the excitation signal. By adding a protection circuit capable of outputting a protection signal of 0 and connecting it between the input terminal of the drive circuit and the processor, the drive circuit can output an excitation signal of 0 based on this protection signal, effectively stopping the output of the excitation signal and achieving the same control objective. As an example, the protection signal can function in the following way: Figure 7 As shown, an AND gate is added to the output of the signal switching circuit 113 and the output of the protection circuit 114, so that the actual input drive signal to the drive circuit 102 is the result of an AND operation between the original first drive signal output by the signal switching circuit 113 and the protection signal, thus making the actual input drive signal 0. Alternatively, it can directly switch from the original first drive signal to the protection signal, for example, by setting switches at the outputs of both circuits (e.g., the protection circuit and the signal switching circuit) (either separate switches or a single-pole double-throw switch) to achieve the on / off state of the two circuits, which can also make the actual drive signal 0. It should be understood that when there is no abnormality, if the implementation method of adding an AND gate is used, the protection circuit can output a signal with a non-zero value (e.g., 1) to ensure that the first drive signal can be input to the drive circuit; if the implementation method of directly switching the signal is used, it will switch to the first drive signal when there is no abnormality, and the protection circuit can output any signal or no signal.

[0065] It should be understood that since the two methods for stopping the drive circuit from outputting the excitation signal are not contradictory, one of them can be executed, or both can be executed, providing double protection and reducing the risk of failing to reliably stop the output excitation signal due to an anomaly in one of the implementation methods. This disclosure does not limit the specific operation for stopping the drive circuit from outputting the excitation signal.

[0066] Optionally, the control method according to embodiments of this disclosure further includes: outputting alarm information when it is determined that the reference signal meets preset abnormal conditions. By outputting an alarm signal when an abnormality is detected, staff can be promptly alerted, facilitating timely intervention and risk elimination, thus fully ensuring safe operation. As an example, the alarm information can be output in any reasonable form, such as outputting an alarm sound, flashing an alarm light, or broadcasting an alarm voice; this disclosure does not impose any limitations on this.

[0067] The topology of a fluxgate current sensor according to a specific embodiment of this disclosure is as follows: Figure 7As shown, a drive switch 111 (default off), a processor 112, a signal switching circuit 113, a protection circuit 114, and an AND gate are added to the existing fluxgate current sensor. The control method of this fluxgate current sensor is as follows: Figure 9 As shown in the diagram. In this specific embodiment, when the fluxgate current sensor is powered on, the fluxgate current sensor's flux status is first detected by executing an open-loop mode (outputting a second drive signal with higher priority), which means detecting whether the circuit under test is powered on. If flux is detected in the fluxgate current sensor, indicating that the circuit under test is powered on, the drive switch is disconnected, and the fluxgate current sensor is not activated. If no flux is detected in the fluxgate current sensor, indicating that the circuit under test is not powered on, the drive switch remains closed, and the system switches to the conventional closed-loop mode (without outputting the second drive signal) to achieve current detection. During current detection, the system continuously checks for abnormalities based on the current first drive signal. If an abnormality is detected, the drive switch is directly disconnected, and a protection signal with a value of 0 is output. This provides protection during normal operation, preventing the drive circuit and sampling circuit from burning out, and outputs alarm information.

[0068] This specific embodiment combines traditional analog circuitry sensors with processor control, making the circuit safer and reducing the failure rate. On one hand, it adds power-on protection, enabling power-on timing protection, reducing the requirements for fluxgate current sensors and solving the problem of easy damage to fluxgate current sensors due to magnetic flux in the core before power-on. On the other hand, based on fluxgate technology, it combines a waveform generator with a protection circuit. By real-time detection and analysis of the waveform of the first drive signal output by the waveform generator, it can determine whether there are any abnormalities. This provides real-time detection and protection during normal operation, a feature not found in traditional sensors. Therefore, this specific embodiment can reduce the risk of sensor damage caused by power-on timing errors and loose connections in fluxgate current sensors, and can be applied in high-temperature and high-vibration environments, such as wind power converters, automotive converters, and vehicle power supplies, significantly reducing the failure rate.

[0069] like Figure 7 As shown, a fluxgate current sensor according to an embodiment of the present disclosure includes: a drive circuit 102 for outputting an excitation signal; a power supply 101; a drive switch 111 connected between the drive circuit 102 and the power supply 101; a processor 112 connected to the drive switch 111; and at least one memory (not shown) storing computer-executable instructions connected to the processor 112, wherein the computer-executable instructions, when executed by the processor, cause the processor to execute a control method for the fluxgate current sensor according to an exemplary embodiment of the present disclosure.

[0070] Processor 112 may include a central processing unit (CPU), a graphics processing unit (GPU), a programmable logic device, a dedicated processor system, a microcontroller, or a microprocessor. By way of example and not limitation, the processor may also include analog processors, digital processors, microprocessors, multi-core processors, processor arrays, network processors, etc.

[0071] The processor 112 can execute instructions or code stored in memory, which can also store data. Instructions and data can also be sent and received over a network via a network interface device, which can employ any known transport protocol.

[0072] The memory can be integrated with the processor 112, for example, by placing RAM or flash memory within an integrated circuit microprocessor. Alternatively, the memory can comprise a separate device, such as an external disk drive, a storage array, or any other storage device usable by a database system. The memory and processor 112 can be operatively coupled, or can communicate with each other, for example, via I / O ports, network connections, etc., enabling the processor 112 to read files stored in the memory.

[0073] In addition, fluxgate current sensors may also include a video display (such as an LCD) and a user interface (such as a keyboard, mouse, touch input device, etc.). All components of a fluxgate current sensor can be interconnected via a bus and / or network.

[0074] Optionally, the fluxgate current sensor further includes a waveform generator 107 and a signal switching circuit 113. The waveform generator 107 is used to output a first drive signal based on a feedback signal. The first drive signal is used to control the drive circuit 102 to output an excitation signal. The processor 112 is used to output a second drive signal in open-loop mode. The second drive signal is used to control the drive circuit 102 to output a preset excitation signal. The input terminal of the signal switching circuit 113 is connected to the output terminal of the waveform generator 107 and the processor 112. The priority of the first drive signal is lower than the priority of the second drive signal. The output terminal of the signal switching circuit 113 is connected to the input terminal of the drive circuit 102.

[0075] Optionally, such as Figure 7 As shown, the fluxgate current sensor may also include a protection circuit 114, which is connected between the input terminal of the drive circuit 102 and the processor 112.

[0076] Optionally, the fluxgate current sensor may also include an alarm device for outputting alarm information. The alarm device may be, for example, an alarm sound output device, an alarm light, or a speaker, with the corresponding alarm information being an alarm sound, a flashing alarm light, and an alarm voice, respectively.

[0077] According to embodiments of the present disclosure, a wind turbine generator set includes a circuit under test and a fluxgate current sensor as described above. The fluxgate current sensor is used to detect the current on the circuit under test. It can operate stably in high-temperature environments to achieve reliable current detection, and it can also reduce the risk of damage to the sensor due to high-frequency vibration.

[0078] Optionally, the circuit under test includes an IGBT circuit, and a fluxgate current sensor is used to detect the output current of the IGBT circuit. The IGBT circuit is, for example, the drive circuit of an air-cooled converter in a wind turbine generator set, which operates in a high-temperature environment of 80℃-100℃. By applying the aforementioned fluxgate current sensor to detect its current, the damage rate of the drive board can be significantly reduced, effectively ensuring the stability of the system and reducing generator power generation losses.

[0079] The control method for a fluxgate current sensor according to embodiments of the present disclosure can be programmed into a computer program and stored on a computer-readable storage medium. When the instructions corresponding to the computer program are executed by a processor, the control method for the fluxgate current sensor as described above can be implemented. Examples of computer-readable storage media include: read-only memory (ROM), random access programmable read-only memory (PROM), electrically erasable programmable read-only memory (EEPROM), random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), flash memory, non-volatile memory, CD-ROM, CD-R, CD+R, CD-RW, CD+RW, DVD-ROM, DVD-R, DVD+R, DVD-RW, DVD+RW, DVD-RAM, BD-ROM, BD-R, BD-R LTH, BD-RE, Blu-ray or optical disc storage, hard disk drive (HDD), solid-state drive (SSD), card storage (such as multimedia cards, secure digital (SD) cards, or ultra-fast digital (XD) cards), magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, and any other device configured to store a computer program and any associated data, data files, and data structures in a non-transitory manner and to provide the computer program and any associated data, data files, and data structures to a processor or computer so that the processor or computer can execute the computer program. In one example, the computer program and any associated data, data files, and data structures are distributed across a networked computer system, such that the computer program and any associated data, data files, and data structures are stored, accessed, and executed in a distributed manner through one or more processors or computers.

[0080] A computer program product according to an embodiment of the present disclosure includes computer instructions that, when executed by at least one processor, cause at least one processor to perform the control method of the fluxgate current sensor as described above.

[0081] This disclosure provides a fluxgate current sensor and its control method, device, wind turbine generator set, and storage medium. By adding a drive switch that is defaulted to being disconnected between the drive circuit and the power supply of the existing fluxgate current sensor, the drive circuit can be kept in an unpowered state by default, avoiding incorrect power-on timing when the power supply is first turned on, thereby achieving the purpose of protecting the drive circuit 102 when powered on. At the same time, after the fluxgate current sensor is powered on, an open-loop mode is first adopted and the drive switch is closed, so that the drive circuit can output a stable and safe preset excitation signal without being affected by feedback signals to test whether the circuit under test is powered on. Based on this, it is determined whether to disconnect the drive switch to reduce damage or switch to closed-loop mode to perform conventional current detection. That is, in the early stage of startup, the high-risk closed-loop mode is directly abandoned and replaced with a safe and reliable switching mode. Without the need for tedious analysis of the many influencing factors in the closed-loop mode, the damage risk of the fluxgate current sensor can be effectively reduced, its reliability improved, maintenance difficulty reduced, and the usage requirements of the fluxgate current sensor lowered.

[0082] The specific embodiments of this disclosure have been described in detail above. Although some embodiments have been shown and described, those skilled in the art should understand that modifications and variations can be made to these embodiments without departing from the principles and spirit of this disclosure, which are defined by the claims and their equivalents. Such modifications and variations should also be within the protection scope of the claims of this disclosure.

Claims

1. A control method for a fluxgate current sensor, characterized in that, The fluxgate current sensor is used to detect the current in the circuit under test using the fluxgate effect. The fluxgate current sensor includes a drive circuit, a power supply, a drive switch, and a processor. The drive circuit outputs an excitation signal to achieve current detection. The drive switch is connected between the drive circuit and the power supply, and is in an off state by default. The processor is connected to the input terminal of the drive circuit and the drive switch, and is used to execute the control method, which includes: In response to the power supply being powered on, an open-loop mode is executed to control the drive circuit to output a preset excitation signal and control the drive switch to close. During the execution of the open-loop mode, a current detection signal is acquired; When the current detection signal indicates that the circuit under test is not powered on, the drive switch remains closed and a closed-loop mode is executed so that the drive circuit outputs an excitation signal based on the feedback signal. When the current detection signal indicates that the circuit under test is powered on, the drive switch is disconnected.

2. The control method as described in claim 1, characterized in that, The fluxgate current sensor also includes a waveform generator and a signal switching circuit. The waveform generator is used to output a first drive signal based on the feedback signal, and the first drive signal is used to control the drive circuit to output the excitation signal. The processor is configured to output a second drive signal in the open-loop mode, the second drive signal being used to control the drive circuit to output the preset excitation signal. The input terminal of the signal switching circuit is connected to the output terminal of the waveform generator and the processor. The priority of the first driving signal is lower than that of the second driving signal. The output terminal of the signal switching circuit is connected to the input terminal of the driving circuit.

3. The control method as described in claim 1 or 2, characterized in that, The control method further includes: During the execution of the closed-loop mode, a signal related to the feedback signal is acquired as a reference signal; If the reference signal is determined to meet a preset abnormal condition, the drive circuit is controlled to stop outputting the excitation signal.

4. The control method as described in claim 3, characterized in that, The reference signal includes the feedback signal, and the preset abnormal condition includes at least one of the following: the feedback signal is 0, or the feedback signal is not a harmonic of the excitation signal; or The reference signal includes a first drive signal output by the waveform generator of the fluxgate current sensor based on the feedback signal. The preset abnormal conditions include at least one of the following: the first drive signal remains unchanged, or the frequency of the first drive signal is not equal to the frequency of the excitation signal.

5. The control method as described in claim 3, characterized in that, The control of the drive circuit to stop outputting the excitation signal includes: disconnecting the drive switch; and / or The fluxgate current sensor further includes a protection circuit connected between the input terminal of the drive circuit and the processor. The step of controlling the drive circuit to stop outputting the excitation signal includes controlling the protection circuit to output a protection signal with a value of 0 to the drive circuit, so that the drive circuit stops outputting the excitation signal.

6. The control method as described in claim 3, characterized in that, The control method further includes: If the reference signal is determined to meet the preset abnormal conditions, an alarm message is output.

7. A fluxgate current sensor, characterized in that, The fluxgate current sensor includes: The drive circuit is used to output an excitation signal to achieve current detection; power supply; A drive switch is connected between the drive circuit and the power supply, and the drive switch is in the off state by default. The processor is connected to the input terminal of the drive circuit and the drive switch; and At least one memory storing computer-executable instructions is connected to the processor. Wherein, when the computer-executable instructions are executed by the processor, the processor is prompted to execute the control method of the fluxgate current sensor as described in any one of claims 1 to 6.

8. A wind turbine generator set, characterized in that, The wind turbine generator set includes: The circuit under test; and The fluxgate current sensor as described in claim 7 is used to detect the current in the circuit under test.

9. The wind turbine generator set as described in claim 8, characterized in that, The circuit under test includes an IGBT circuit, and the fluxgate current sensor is used to detect the output current of the IGBT circuit.

10. A computer-readable storage medium, characterized in that, When the instructions in the computer-readable storage medium are executed by at least one processor, the at least one processor causes the processor to perform the control method of the fluxgate current sensor as described in any one of claims 1 to 6.

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