Excitation control method, excitation control circuit and current sensor

Abstract

The invention discloses an excitation control method, an excitation control circuit and a current sensor, and the method comprises the steps: a control unit is provided with a preset threshold value, and the control unit comprises an excitation signal used for controlling the output of an excitation unit; the excitation unit outputs excitation frequency and applies the excitation frequency to the magnetic core coil; the control unit collects signals passing through the magnetic core coil and obtains the time when the magnetic core coil enters deep saturation, the ratio of the time when the magnetic core coil enters deep saturation to the corresponding period is n%, and when n% is located at a preset threshold value, the control unit controls the excitation unit to stop frequency conversion; and when n% is not located at the preset threshold value, the control unit adjusts the excitation frequency output by the excitation unit until n% is located at the preset threshold value. According to the method, each product can achieve the optimal excitation effect, so that the influence of residual magnetism is eliminated, the service life of the product is prolonged, and the leakage current detection is more accurate.

Description

Technical Field

[0001] The present invention relates to the field of electrical technology, and particularly to an excitation control method, an excitation control circuit, and a current sensor. Background Art

[0002] Leakage detection is one of the crucial safety measures in electrical systems, used to monitor whether current flows through an unexpected path, thereby avoiding electric shock accidents and equipment damage. Leakage is usually caused by insulation faults, equipment aging, or improper operation. Therefore, timely detection and correction of leakage problems are crucial for maintaining the safety of electrical systems.

[0003] Among them, DC leakage detection technology has wide applications and market prospects in modern electrical systems. Its main application fields include industrial automation, renewable energy systems, electric vehicles, and power equipment in special environments. In industrial automation, DC leakage detection systems can be used to monitor factory equipment and mechanical devices, improving the safety and stability of production lines. In renewable energy systems, such as solar and wind power generation systems, DC leakage detection helps to timely detect leakage problems in equipment such as photovoltaic panels and inverters, ensuring the efficient operation of the system. In addition, in the field of electric vehicles, DC leakage detection is a key technology to ensure the safe operation of battery systems, which is crucial for the wide popularization of electric vehicles, electric bicycles, etc. With the continuous development and upgrading of electrical systems, DC leakage detection technology is expected to have greater demand in the market and become an important part of the power safety field.

[0004] The current mainstream DC leakage current detection scheme uses magnetic modulation technology. The magnetic modulation scheme applies an external excitation to a magnetic material, and during its magnetization process, oscillations will occur. If there are other magnetic fields or currents around, they will affect this oscillating magnetic moment, resulting in an offset of the magnetic moment oscillation. By measuring this offset, information about the measured magnetic field or measured current can be obtained.

[0005] A magnetic core coil is provided inside the mutual inductor. During the working process, an external excitation needs to be applied to the magnetic core coil to give the magnetic core coil an excitation frequency. Each magnetic core coil has a corresponding optimal excitation frequency. The excitation frequency should make the magnetism just enter the deep saturation state. Using this frequency can not only ensure that the magnetism is completely saturated but also prevent it from being in the saturated state for too long. Complete saturation of the magnetism can avoid the influence of residual magnetism on parameter accuracy, while being in the saturated state for a long time will cause waste of power consumption.

[0006] However, the mainstream fluxgate solutions on the market specify using a fixed-frequency excitation signal before leaving the factory. Due to differences in size, weight, and annealing process of the core coils, some of the products produced are not in a deeply saturated state, and some products do not enter the saturated state. The states of each product vary greatly, seriously affecting the actual use effect and subsequent leakage current detection. Summary of the Invention

[0007] Therefore, the technical problem to be solved by the present invention is how to give each product the optimal excitation frequency. For this purpose, an excitation control method includes:

[0008] A control unit, the control unit is provided with a preset threshold, and the control unit includes an excitation signal used to control the output of the excitation unit;

[0009] An excitation unit, the control unit is electrically connected to the excitation unit, and the excitation unit outputs an excitation frequency and applies it to the core coil;

[0010] The control unit collects the signal passing through the core coil, obtains the time when the core coil enters deep saturation, and the ratio of the time when the core coil enters deep saturation to the corresponding period is n%. When n% is within the preset threshold, the control unit controls the excitation unit to stop frequency conversion; when n% is not within the preset threshold, the control unit adjusts the excitation frequency output by the excitation unit until n% is within the preset threshold.

[0011] When n% is less than the preset threshold, the excitation frequency output by the excitation unit decreases step by step; when n% is greater than the preset threshold, the excitation frequency output by the excitation unit increases step by step.

[0012] The excitation unit adjusts and outputs the excitation frequency at least every one period.

[0013] When n% is within the preset threshold, the control unit maintains collecting the signal passing through the core coil for at least one period.

[0014] The preset threshold is 3% - 15%.

[0015] The control unit includes an adjustment button, and the control unit generates the excitation signal when receiving the signal of the adjustment button.

[0016] The control unit includes a communication module, and the control unit generates the excitation signal when receiving the signal of the communication module.

[0017] The communication module is connected by wire or wirelessly.

[0018] The control unit includes a timing detection module, and the timing detection module detects n% at regular intervals.

[0019] The communication module is cooperatively connected with the APP; or the communication module is cooperatively connected with the Internet of Things.

[0020] Therefore, the technical problem to be solved by the present invention lies in how to give each product the best excitation frequency. For this purpose, an excitation control circuit adopts the above-mentioned excitation control method.

[0021] Therefore, the technical problem to be solved by the present invention lies in how to give each product the best excitation frequency. For this purpose, a current sensor includes the above-mentioned excitation control circuit.

[0022] The technical solution of the present invention has the following advantages:

[0023] 1. An excitation control method provided by the present invention. In this control, first an excitation frequency is output, then the time when the magnetic core coil enters deep saturation is obtained, the ratio n% of the time when the magnetic core coil enters deep saturation to the period is calculated, and through the comparison of n% with a preset threshold, the excitation frequency is adjusted to form a real-time adjustment effect, so that the excitation frequency reaches an optimal excitation effect. When the optimal excitation frequency is reached, the frequency conversion is stopped, and the output is always at the optimal excitation frequency to complete the working effect of a product. This method enables each product to achieve the optimal excitation effect, thereby eliminating the influence of residual magnetism, increasing the service life of the product, and further making the leakage current detection more accurate.

[0024] 2. An excitation control method provided by the present invention. By comparing and analyzing n% in real time, the excitation frequency can be quickly adjusted, so as to quickly select the optimal excitation frequency.

[0025] 3. An excitation control method provided by the present invention. One excitation frequency corresponds to one or more periods, and the control unit can better obtain the time when the magnetic core coil enters deep saturation, improve the overall measurement accuracy, and thus select the optimal excitation frequency.

[0026] 4. An excitation control method provided by the present invention. Through the setting of at least one period, misoperation is prevented and the detection accuracy is improved. For example, in the second period, when n% changes and n% is not within the preset threshold, the excitation frequency will be readjusted at this time.

[0027] 5. An excitation control method provided by the present invention. The interval of the preset threshold can be set according to actual needs, so as to obtain an interval range, enabling all products to achieve the optimal excitation effect.

[0028] 6. A kind of excitation control method provided by the present invention adjusts the settings of the adjustment buttons. When the product leaves the factory, the operator can adjust according to actual needs to obtain the optimal excitation frequency. Secondly, during the use of the product, the loss of the current sensor causes the excitation frequency at the time of leaving the factory to no longer be the optimal excitation frequency. The optimal excitation frequency can be re-controlled and adjusted through the adjustment buttons. Or, during transportation or use, if the magnetic core coil drops or is impacted, it will affect the optimal excitation frequency of the magnetic core coil. Therefore, the optimal excitation frequency can also be re-controlled and adjusted through the adjustment buttons.

[0029] 7. A kind of excitation control method provided by the present invention. The communication module forms an external control effect, which can be wired control or wireless control, so as to re-adjust the optimal excitation frequency through the control unit to obtain the optimal excitation frequency.

[0030] 8. A kind of excitation control method provided by the present invention. Wired connection can be through 485 communication or other communication connection methods, and wireless connection can be local area network or WIFI or APP or Internet of Things, etc., to form a wireless control effect, and the operator can better achieve the control effect and select the optimal excitation frequency.

[0031] 9. A kind of excitation control circuit provided by the present invention. The timing detection module forms a timing detection effect, which can be daily or weekly or monthly or quarterly, etc. The operator can select the corresponding time according to actual needs to form a real-time adjustment effect.

[0032] 10. A kind of current sensor provided by the present invention. By adopting this kind of circuit for the current sensor, the magnetic core coil inside the current sensor can obtain the optimal excitation effect, improve the accuracy of detecting leakage current, and at the same time can reduce the damage of the magnetic core coil and improve the service life. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0034] Figure 1 It is a waveform diagram of the excitation frequency provided by the present invention and the waveform generated by applying the excitation frequency to the magnetic core coil;

[0035] Figure 2 It is a waveform diagram of the excitation frequency provided by the present invention and the waveform generated by applying the excitation frequency to the magnetic core coil;

[0036] Figure 3This invention provides a waveform diagram of the excitation frequency and the waveform generated by applying the excitation frequency to the core coil;

[0037] Figure 4 This invention provides a waveform diagram of the excitation frequency;

[0038] Figure 5 This invention provides a connection block diagram of an excitation control method.

[0039] Description of the reference numerals:

[0040] 1. Control unit; 2. Excitation unit; 3. Core coil. Specific embodiments

[0041] Next, the technical solution of this invention will be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of this invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of this invention without making creative efforts shall fall within the scope of protection of this invention.

[0042] In the description of this invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing this invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of this invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0043] In the description of this invention, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in this invention can be understood according to specific situations.

[0044] In addition, the technical features involved in different embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0045] Embodiment 1

[0046] This embodiment provides an excitation control method, as shown in the attached Figures 1-5 figure, including:

[0047] Control unit 1 is provided with a preset threshold value. The preset threshold value can be a fixed value or an interval. In this embodiment, it is preferably an interval. The preset threshold value refers to the ratio of the time when the core coil 3 enters deep saturation to the corresponding period at the optimal excitation frequency. Here, the preset threshold value can be set according to actual requirements so as to ensure that each core coil 3 can achieve the best excitation effect. The control unit 1 includes an excitation signal for controlling the excitation unit. The control unit 1 gives a signal to the excitation unit so that the excitation unit outputs an excitation frequency. In this embodiment, the control unit 1 is a unit composed of chips to form a control effect.

[0048] Excitation unit 2. The control unit 1 is electrically connected to the excitation unit 2 to form the effect that the control unit 1 controls the excitation unit 2. The excitation unit 2 outputs an excitation frequency and applies it to the core coil 3 to form an external excitation of the core coil 3. In this embodiment, the excitation unit 2 specifically outputs a square wave, and the square wave is applied to the core coil 3. Simply speaking, the excitation unit 2 is electrically connected to the core coil 3, and the generated square wave cooperates with the core coil 3. Here, the excitation frequency generated by the excitation unit 2 is not only one or two. It is controlled by the control unit 1 and can output an excitation frequency within a range, which can be any excitation frequency between 1 KHz and 10 KHz, or can be any excitation frequency between 500 Hz and 15 KHz. How the control unit 1 realizes the control of the excitation frequency of the excitation unit 2 is prior art, so it will not be described in detail in this embodiment. The excitation unit 2 can form a frequency conversion control according to the instruction of the control unit 1, that is, the excitation frequency can be changed at any time. When the core coil 3 enters deep saturation, the waveform of the core coil 3 will generate a flat line segment, which is located at the uppermost end or the lowermost end of the waveform. The time of this flat line segment is the time when the core coil 3 enters deep saturation.

[0049] The control unit 1 collects the signal passing through the core coil 3 to obtain the time when the core coil 3 enters deep saturation. The ratio of the time when the core coil 3 enters deep saturation to the corresponding period is n%. Here, the corresponding period is specifically the period corresponding to the excitation frequency, and the corresponding period duration can be obtained from f = 1 / T.

[0050] When n% is at the preset threshold, the control unit 1 controls the excitation unit 2 to stop frequency conversion. Stopping frequency conversion means stopping the change of the excitation frequency and maintaining the output at this excitation frequency. When n% is at the preset threshold, the excitation frequency obtained at this time is the optimal excitation frequency. It should be noted that in this embodiment, the optimal excitation frequency is an interval range, not a fixed value under ideal conditions. This optimal excitation frequency is determined through experimental calculations for the selection of the preset threshold, and using this frequency can ensure that the magnetic core coil 3 is completely saturated magnetically and will not be in the saturated state for too long, excluding the influence of residual magnetism. Complete magnetic saturation can avoid the influence of residual magnetism on parameter accuracy, and being in the saturated state for a long time will lead to waste of power consumption. The optimal excitation frequency is continuously output and continuously applied to the magnetic core coil 3.

[0051] When n% is not at the preset threshold, the control unit 1 adjusts the excitation frequency output by the excitation unit 2 until n% is at the preset threshold. Here, the excitation frequency is set in real-time adjustment. Based on the n% obtained from an excitation frequency, it is determined whether n% is at the preset threshold at this excitation frequency. If it is still not at the preset threshold, the excitation frequency is continuously adjusted until n% is at the preset threshold. Here, the excitation frequency may be adjusted several times to obtain the optimal excitation frequency, or it may be adjusted a dozen or dozens of times, depending on the actual situation. Therefore, it can also be considered as frequency conversion, adjusting the excitation frequency in real-time and replacing and changing the excitation frequency.

[0052] In this control method, an excitation frequency is first output, and then the time for the magnetic core coil 3 to enter deep saturation is obtained. The ratio n% of the time for the magnetic core coil 3 to enter deep saturation to the period is calculated. By comparing n% with the preset threshold, the excitation frequency is adjusted to form a real-time adjustment effect, so that the excitation frequency reaches an optimal excitation effect. When the optimal excitation frequency is reached, the frequency conversion is stopped to complete the working effect of a product. This method enables each product to achieve the optimal excitation effect, thereby excluding the influence of residual magnetism, increasing the service life of the product, and further making the leakage current detection more accurate. For example, in the prior art, there are also square waves composed of multiple different excitation frequencies. Although several of these excitation frequencies will also cause the magnetic core coil 3 to enter deep saturation, that is, the optimal excitation frequency in this embodiment, there will also be several excitation frequencies that are lower or higher than the optimal excitation frequency, causing the magnetic core coil 3 to be in the saturated state for a long time, resulting in waste of power consumption and affecting the service life. After the application of the present application is stabilized, the optimal excitation frequency will be continuously output to ensure the normal use of the product and thus improve the detection accuracy of the product.

[0053] Specifically, when n% is less than the preset threshold, the excitation frequency output by the excitation unit 2 decreases step by step. Here, the step-by-step decrease can be an arithmetic decrease. For example, the initial excitation frequency is 5KHz, and then it decreases by 0.1KHz each time, or it can decrease by 0.2KHz each time. Those skilled in the art can select and set according to actual needs. It should also be noted here that when the preset threshold is an interval, when n% is less than the minimum value of the preset threshold, the excitation frequency output by the excitation unit 2 decreases step by step. When n% is greater than the preset threshold, the excitation frequency output by the excitation unit 2 increases step by step. Here, the step-by-step increase can be an arithmetic increase. For example, the initial excitation frequency is 5KHz, and then it increases by 0.1KHz each time, or it can increase by 0.2KHz each time. Those skilled in the art can select and set according to actual needs. It should also be noted here that when the preset threshold is an interval, when n% is greater than the maximum value of the preset threshold, the excitation frequency output by the excitation unit 2 increases step by step. By comparing and analyzing n% in real time, the excitation frequency can be quickly adjusted, so as to quickly select the best excitation frequency. In addition, the excitation frequency can also be pulsating, with irregular pulsations, and the fundamental excitation frequency randomly pulsates within the range of 1KHz - 10KHz, so as to select the best excitation frequency. The excitation frequency can also be divided into several units, and an excitation frequency is extracted from each unit and then tested.

[0054] Specifically, the excitation unit 2 adjusts the output excitation frequency at least every one cycle. When an excitation frequency is applied to the core coil 3 and the calculated n% is not within the preset threshold, another excitation frequency is immediately adjusted and output to form another cycle. The adjacent two cycles are connected until the best excitation frequency appears, and then the operation of the excitation unit 2 is stopped. When the interval cycle is two, two consistent waveforms are formed. One excitation frequency corresponds to one or more cycles. The control unit 1 can better obtain the time when the core coil 3 enters deep saturation, improve the overall measurement accuracy, and thus select the best excitation frequency. Those skilled in the art can select a suitable interval cycle according to actual needs. When the computing power of the chip is sufficient, the best excitation frequency can also be quickly obtained by spacing one cycle. When the computing power of the chip is insufficient or more accurate best excitation frequency is desired, the number of cycles can be increased, so as to accurately measure and obtain the best excitation frequency. Here, the computing power of the chip is proportional to the cost of the chip.

[0055] Specifically, when n% is within a preset threshold, the control unit 1 maintains at least one cycle of signal acquisition through the core coil 3. By setting at least one cycle, false operations are prevented and the detection accuracy is improved. In this embodiment, taking maintaining three cycles of acquisition as an example, when n% is within the preset threshold in the first cycle and changes in the second cycle such that n% is not within the preset threshold, the excitation frequency will be readjusted again to prevent interference and ensure the best excitation frequency is obtained. In addition, it is also possible to maintain five cycles of acquisition or longer. When the control unit 1 continuously acquires signals, real-time detection and permanent detection are formed, and the best excitation frequency is always maintained. The time interval of this permanent detection is at the microsecond level, and its detection accuracy is much greater than that of timed detection.

[0056] Specifically, the preset threshold is 3% - 15%. The range of the preset threshold can be set according to actual needs to obtain a range so that all products can achieve the best excitation effect. Those skilled in the art can obtain the range of the preset threshold based on experimental data or actual experience, and it can also be other ranges.

[0057] Specifically, the control unit 1 includes an adjustment button, and the control unit 1 generates an excitation signal when receiving the signal of the adjustment button. With the setting of the adjustment button, when the product leaves the factory, the operator can adjust it according to actual needs to obtain the best excitation frequency. Secondly, during the use of the product, the loss of the current sensor (such as parameter changes caused by core oxidation, etc.) results in the excitation frequency at the time of leaving the factory no longer being the best excitation frequency. The best excitation frequency can be re-controlled and adjusted through the adjustment button. Or, during transportation or use, if the core coil 3 drops or is impacted, it will affect the best excitation frequency of the core coil 3. Therefore, the best excitation frequency can also be re-controlled and adjusted through the adjustment button.

[0058] Specifically, the control unit 1 includes a communication module, and the control unit 1 generates an excitation signal when receiving the signal of the communication module. Both the communication module and the adjustment button have an adjustment effect, forming a real-time adjustment effect of the best excitation frequency. The communication module forms an external control effect, which can be wired control or wireless control, so that the best excitation frequency can be readjusted through the control unit 1 to obtain the best excitation frequency.

[0059] Specifically, the communication module is connected in a wired or wireless manner. Wired connection can be through 485 communication or other communication connection methods, and wireless connection can be a local area network, WIFI, APP, Internet of Things, etc. The operator can form a control effect through wired or wireless means, enabling the core coil 3 to re-obtain the best excitation frequency, thereby improving the leakage current detection ability of the core coil 3.

[0060] Specifically, the control unit 1 includes a timing detection module, which detects n% at regular intervals. The timing detection module can achieve the effect of timing detection, which can be daily, weekly, monthly, quarterly, etc. The operator can select the corresponding time according to actual needs, so as to achieve the effect of real-time adjustment.

[0061] Specifically, when the saturation time obtained at the optimal excitation frequency deviates from the time set by the manufacturer, continue to adjust the excitation frequency until the saturation time matches the time set by the manufacturer.

[0062] Specifically, the optimal excitation frequency has been regulated by the excitation control method before leaving the factory to adjust the excitation frequency in real time, so as to obtain an optimal excitation frequency. This control and adjustment method has been described in detail in Embodiment 1, so it will not be elaborated in this embodiment.

[0063] After the current sensor leaves the factory, due to the loss of the current sensor (such as parameter changes caused by reasons such as magnetic core oxidation), the excitation frequency at the time of leaving the factory is not the optimal excitation frequency. At this time, the excitation frequency needs to be changed. A control signal for adjustment can be given to the control unit 1 through an adjustment button or a communication module, so as to obtain a new optimal excitation frequency. Here, the communication module can cooperate with the APP or the Internet of Things to form the effect of wireless control, so that the operator can better achieve the control effect and select the optimal excitation frequency. Moreover, by cooperating with the Internet of Things, the effect of big data control can be formed, so as to achieve the effect of real-time monitoring.

[0064] In addition, when the current sensor drops or is impacted, it will also affect the parameters of the magnetic core coil 3, and it will also cause the excitation frequency at the time of leaving the factory not to be the optimal excitation frequency, and it can also be adjusted by the above operation method.

[0065] Compared with the prior art, the current sensor in the prior art has an excitation frequency when leaving the factory, and its excitation frequency will not change until the current sensor reaches the end of its life. In this embodiment, real-time monitoring and adjustment are formed for the current sensor, so that the magnetic core coil 3 in the current sensor always remains at the optimal excitation frequency, thereby improving the accurate detection effect of the leakage current. Moreover, this setting can also improve the service life of the current sensor.

[0066] Embodiment 2

[0067] An excitation control circuit provided by the present invention adopts the excitation control method in Embodiment 1. The excitation control circuit is located on the circuit board and cooperates with the circuit board through various components such as chips to form an overall circuit. At the same time, a control program is burned into the chip, and the software and hardware cooperate to find the optimal excitation frequency. Those skilled in the art can easily think of the relevant hardware layout and program writing on the basis of this embodiment, so it will not be elaborated in this embodiment.

[0068] Embodiment 3

[0069] A current sensor provided by the present invention includes an excitation control circuit. The excitation control circuit is located on a circuit board, which can be accommodated inside the current sensor or can be located outside the current sensor to form a relatively independent unit. The current sensor is electrically connected to the circuit board. By adopting such a circuit in the current sensor, the magnetic core coil 3 inside the current sensor can obtain the best excitation effect, improving the accuracy of detecting leakage current. At the same time, it can also reduce the damage to the magnetic core coil 3 and extend the service life.

[0070] Specifically, the magnetic core coil 3 is also located inside the current sensor, which is a prior art. Therefore, the connection and fixing relationship between the magnetic core coil 3 and the current sensor will not be described in detail in this embodiment. Here, the current sensor can include an instrument transformer or can be a current detection structure with other configurations.

[0071] Specifically, in addition to the above, the circuit board is also provided with a leakage current detection unit, an alarm unit, etc., which are prior arts. Therefore, they will not be described in detail in this embodiment. In addition, the circuit board for detecting leakage current and the circuit board where the excitation control circuit is located are two independent circuit boards, and the two are electrically connected through a conductive member.

[0072] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims

1. An excitation control method, characterized in that, Comprising: A control unit (1), the control unit (1) being provided with a preset threshold value, the control unit (1) including an excitation signal for controlling the output of the excitation unit (2); An excitation unit (2), the control unit (1) being electrically connected to the excitation unit (2), the excitation unit (2) outputting an excitation frequency and applying it to the core coil (3); The control unit (1) collects the signal passing through the core coil (3), obtains the time when the core coil (3) enters deep saturation, and the ratio of the time when the core coil (3) enters deep saturation to the corresponding period is n%. When n% is within the preset threshold value, the control unit (1) controls the excitation unit (2) to stop frequency conversion; when n% is not within the preset threshold value, the control unit (1) adjusts the excitation frequency output by the excitation unit (2) until n% is within the preset threshold value.

2. The excitation control method according to claim 1, wherein When n% is less than the preset threshold value, the excitation frequency output by the excitation unit (2) decreases step by step; when n% is greater than the preset threshold value, the excitation frequency output by the excitation unit (2) increases step by step.

3. The excitation control method according to claim 1, wherein The excitation unit (2) adjusts and outputs the excitation frequency every at least one period.

4. The excitation control method according to claim 1, wherein When n% is within the preset threshold value, the control unit (1) maintains collecting the signal passing through the core coil (3) for at least one period.

5. The excitation control method according to claim 1, wherein The preset threshold value is 3% - 15%.

6. The excitation control method according to claim 1, characterized in that The control unit (1) includes an adjustment button, and the control unit (1) generates the excitation signal upon receiving the signal of the adjustment button.

7. The excitation control method according to claim 1, characterized in that The control unit (1) includes a communication module, and the control unit (1) generates the excitation signal upon receiving the signal of the communication module.

8. The excitation control method according to claim 7, wherein The communication module is cooperatively connected with an APP; or the communication module is cooperatively connected with the Internet of Things.

9. An excitation control circuit, characterized in that, Adopt the excitation control method according to any one of claims 1 - 8.

10. A current sensor, characterized in that, Include the excitation control circuit according to claim 9.

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