Disclosure of Invention
The invention mainly aims to provide a current sensor with a current transformer, electronic equipment and a current measurement method, and aims to solve the technical problem of huge volume caused by directly applying the current transformer to the current sensor in the prior art.
To achieve the above object, a first aspect of the present invention proposes a current sensor comprising:
The mutual inductance module is used for inducing an alternating magnetic field generated by a wire in the annular magnetic core and outputting a first signal through a coil encircling the annular magnetic core;
The protection module is used for outputting a second signal lower than a first threshold value in the first signals;
the current acquisition module is used for adjusting the voltage of the first resistor according to the second signal and outputting a third signal;
The rectification module is used for adjusting the second signal into a direct current signal with higher voltage;
The energy storage voltage stabilizing module is used for storing the direct current signal into electric energy with stable voltage and/or supplying power to the control module;
The control module is used for collecting the current voltage of the energy storage voltage stabilizing module, determining the current of the conducting wire according to the third signal, determining whether to drive the direct current signal to transmit to the energy storage voltage stabilizing module according to the current voltage, and determining whether to drive the second signal to transmit to the current collecting unit according to the current voltage.
According to some embodiments of the invention, the control module comprises:
the first switch is positioned between the protection module and the current acquisition module and is used for controlling the coupling state of the protection module and the current acquisition module;
The second switch is positioned between the rectifying module and the energy storage voltage stabilizing module and is used for controlling the coupling state of the rectifying module and the energy storage voltage stabilizing module;
the voltage acquisition unit is electrically coupled with the energy storage voltage stabilizing module and is used for acquiring the current voltage of the energy storage voltage stabilizing module;
the current determining unit is electrically coupled with the current collecting unit and is used for determining the current of the wire according to the third signal;
The control unit is used for acquiring the current voltage and the current, driving the second switch and the first switch to be in an open and closed state respectively when the current voltage is higher than a second threshold value and determining the current as the current value of the lead, and driving the second switch and the second switch to be in an open and closed state respectively when the current voltage is lower than a third threshold value and stopping determining the current as the current value of the lead;
the energy storage voltage stabilizing module is used for supplying power to the voltage acquisition unit, the current determining unit and the control unit, and the power supply voltage is a first voltage.
According to some embodiments of the invention, the first switch is a normally-on field effect transistor and the second switch is a normally-off field effect transistor;
The control unit can further control the closing state of the first switch by adjusting the voltage of the first switch;
The control unit is capable of further controlling the closed state of the second switch by adjusting the voltage of the second switch.
According to some embodiments of the invention, the mutual inductance module comprises the toroidal core and the coil;
The coil is used for inducing the alternating magnetic field generated by the alternating electric field in the lead and generating induced electromotive force under the action of the alternating magnetic field;
The coil is made of a high magnetic conduction material.
According to some embodiments of the invention, the protection module is configured to monitor a voltage of the first signal, compare the voltage with the first threshold, send the first signal to a bleeder unit for release when the voltage is higher than the first threshold, and output the first signal to the rectifying module or the current collecting module when the voltage is lower than the first threshold.
According to some embodiments of the invention, the energy storage and voltage stabilizing module comprises:
The energy storage capacitor unit is electrically coupled with the output end of the rectifying module and is used for storing the direct current signal as electric energy;
The voltage stabilizing unit is electrically coupled with the energy storage capacitor unit and is used for adjusting the output voltage of the energy storage voltage stabilizing module to at least one preset voltage; when the energy storage voltage stabilizing module supplies power for the control module, the preset voltage is the first voltage.
According to some embodiments of the invention, the control unit is configured to, when the current voltage is higher than a second threshold value, sequentially perform the following steps:
driving the first switch to be in a closed state;
driving the second switch to be in an off state;
acquiring a third signal output by the current acquisition module;
And determining the current value of the wire according to the third signal.
According to some embodiments of the invention, the control unit is configured to, when the current voltage is lower than a third threshold value, sequentially perform the following steps:
Driving the second switch to be in a closed state;
And driving the first switch to be in an off state.
To achieve the above object, a second aspect of the present invention provides a current measurement method, to which the above current sensor is applied, the method comprising the steps of:
The alternating magnetic field generated by the conducting wire in the annular magnetic core is induced by the mutual inductance module, the protection module, the rectifying module and the energy storage voltage stabilizing module which are electrically coupled in sequence, and electric energy with stable voltage is stored in the energy storage voltage stabilizing module;
the energy storage voltage stabilizing module is used for supplying power to the control module;
continuously collecting the current voltage of the energy storage voltage stabilizing module through the control module;
The control module judges whether the current voltage is higher than a second threshold value, drives the rectifying module to be decoupled from the energy storage and voltage stabilizing module and electrically coupled with the current acquisition module when the current voltage is higher than the second threshold value, and further senses the current of the lead through the current acquisition module to output a third signal;
The control module determines the current value of the wire according to the third signal through the control unit;
The control unit judges whether the current voltage is reduced to a third threshold value or not, and drives the rectifying module to be decoupled from the energy storage voltage stabilizing module when the current voltage is lower than the third threshold value, and the rectifying module is electrically coupled with the current acquisition module so as to store the electric energy in the energy storage voltage stabilizing module again.
In order to achieve the purpose of the invention, a third aspect of the invention provides an electronic device, which at least comprises a current sensor, wherein the current sensor is the current sensor or is prepared by adopting the current measuring method.
Compared with the prior art, the invention has the following technical effects:
the current sensor disclosed by the invention realizes the functions of CT electricity taking and current measurement through the synergistic effect of the mutual inductance module, the protection module, the current acquisition module, the rectifying module, the energy storage voltage stabilizing module and the control module, avoids repeated arrangement of the mutual inductance module and the protection module, and can greatly reduce the volume of the current sensor and reduce the equipment cost.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that, if directional indications (such as up, down, left, right, front, and rear are referred to in the embodiments of the present invention), the directional indications are merely used to explain the relative positional relationship, movement conditions, and the like between the components in a specific posture, and if the specific posture is changed, the directional indications are correspondingly changed.
In addition, if there is a description of "first", "second", etc. in the embodiments of the present invention, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, if "and/or" and/or "are used throughout, the meaning includes three parallel schemes, for example," a and/or B "including a scheme, or B scheme, or a scheme where a and B are satisfied simultaneously. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present invention.
The current sensor is a device for detecting current and is generally applied to actual measurement and protection systems of current, such as the fields of photovoltaics, wind power, electric power, smart grids, railway motor and electricity, aerospace, new energy automobiles and the like, and plays a vital role in ensuring the safety and stability of the systems.
Since current sensors are active measurements, how to power high voltage current sensors often becomes a very critical issue. For example, when monitoring high voltage overhead lines, power cables, power distribution units, etc., there is typically no suitable low voltage power supply nearby for use with the current sensor.
At present, a current transformer is mainly adopted to take electricity from a high-voltage line. If the current transformer is directly applied to the current sensor, the volume and the cost of the equipment are easy to increase.
Therefore, it is necessary to solve the technical problem of the prior art that the current transformer is directly applied to the current sensor to cause huge volume.
To achieve the above object, an embodiment of the present invention provides a current sensor. The current sensor comprises a mutual inductance module, a protection module, a rectifying module, an energy storage voltage stabilizing module, a control module and a current acquisition module, wherein the current sensor can realize the energy storage process of an energy storage capacitor in the energy storage voltage stabilizing module when the mutual inductance module, the protection module, the rectifying module and the energy storage voltage stabilizing module are electrically coupled in sequence, the current sensor can realize the current measurement of a wire in an annular magnetic core in the mutual inductance module when the mutual inductance module, the protection module, the current acquisition module and the control module are electrically coupled in sequence, and the current sensor can realize the power supply of the control module and the real-time voltage monitoring of the energy storage voltage stabilizing module through the control module when the energy storage voltage stabilizing module and the control module are electrically coupled in sequence. The electric coupling relation between the rectifying module and the energy storage voltage stabilizing module and the electric coupling relation between the protecting module and the current collecting module can be driven by the control module to change.
Specifically, as shown in fig. 1, the current sensor in the embodiment of the invention includes a mutual inductance module 100, a protection module 200, a rectification module 300, an energy storage voltage stabilizing module 400, a control module 500 and a current acquisition module 600.
The mutual inductance module 100 includes a toroidal core and a coil surrounding the toroidal core.
The mutual inductance module 100 can be used for inducing an alternating magnetic field generated by a wire in the toroidal core, and outputting a first signal through a coil surrounding the toroidal core.
The coil is used for inducing an alternating magnetic field generated by an alternating electric field in the lead and generating induced electromotive force under the action of the alternating magnetic field. The coil is preferably a high permeability material.
Because the energy taking and current measuring functions are realized at the same time, the magnetic core is preferably a soft magnetic material with high magnetic conductivity, such as permalloy, nanocrystalline and the like. A core with a high initial permeability may achieve a better energy pick-up under low current conditions.
Wherein, the protection module 200 may be configured to obtain a second signal of the first signals that is lower than the first threshold.
The protection module 200 is configured to monitor a voltage of the first signal, compare the voltage of the first signal with a first threshold, and push the first signal to the relief unit for release if the voltage of the first signal is not lower than the first threshold, and output the first signal if the voltage of the first signal is lower than the first threshold, that is, ensure that the second signal output by the protection module 200 is a signal lower than the first threshold in the first signal.
The protection module 200 of the embodiment of the invention comprises a silicon controlled rectifier, a power resistor and a voltage comparator, and drives the silicon controlled rectifier to be conducted when the voltage of the first signal exceeds a first threshold value, so that redundant electric energy is converted into heat energy through the power resistor to be discharged.
In yet another embodiment, protection module 200 includes a transient overvoltage protection unit and an energy bleed unit. The transient overvoltage protection unit is electrically coupled to the output end of the coil in the mutual inductance module, and is used for protecting the rectifying module 300, the energy storage voltage stabilizing module 400, the control module 500, the current acquisition module 600 and the like in the subsequent circuit from being damaged by transient overvoltage. The energy discharge unit is electrically coupled to the output of the instantaneous overvoltage protection unit. The energy bleed unit includes an energy bleed topology and a comparator operable to block signal output not below a first threshold.
The rectifying module 300 is configured to rectify and filter the second signal and output a dc signal.
The rectifying module 300 may adopt a voltage-doubler rectifying circuit, and rectify and filter the second signal to output a dc signal through the voltage-doubler rectifying circuit, and simultaneously, regulate the voltage of the dc signal, that is, the voltage of the dc signal is higher than the voltage of the second signal.
It should be appreciated that the voltage output from the coil in the transformer module 100 is generally low, and the voltage is sufficiently high by the voltage doubler rectifier circuit, so as to improve the working efficiency of the energy storage and voltage stabilizing module 400.
The current collection module 600 is configured to adjust a voltage of the first resistor according to the second signal, and output a third signal.
The current acquisition module 600 includes a first resistor across which a voltage varies with the second signal. The third signal is used for feeding back the voltage information of the two ends of the first resistor.
The energy storage voltage stabilizing module 400 is used for storing the direct current signal as electric energy with stable voltage and supplying power to the control module.
The energy storage voltage stabilizing module 400 of the embodiment of the invention is also used for ensuring the stability of the internal power supply of the current sensor and avoiding the influence of power grid fluctuation on the working stability of the sensor.
When the rectifying module 300 is electrically coupled with the energy storage voltage stabilizing module 400, the mutual inductance module 100, the protection module 200, the rectifying module 300 and the energy storage voltage stabilizing module 400 are electrically coupled in sequence, so that the alternating magnetic field of the lead can be converted into electric energy for storage, and the electric energy is used as a power supply to supply power for the control module after a certain amount of electric energy is stored.
When the protection module 200 is electrically coupled with the current acquisition module 600, the mutual inductance module 100, the protection module 200, the current acquisition module 600 and the control module 500 are electrically coupled in sequence, and on the premise that the energy storage voltage stabilizing module 400 supplies power for the control module, acquisition of an alternating magnetic field generated by a wire is realized, so that the current of the wire is determined.
It should be understood that this step is provided that the energy storage capacitor in the energy storage voltage stabilizing module 400 stores enough electric energy.
The energy storage and voltage stabilization module 400 of the embodiment of the invention comprises an energy storage capacitor unit and a voltage stabilization unit, wherein the energy storage capacitor unit is used for converting an alternating magnetic field into electric energy, and the voltage stabilization unit is used for stabilizing the output voltage of the energy storage and voltage stabilization module.
The control module 500 is configured to collect a current voltage of the energy storage and voltage stabilizing module.
When the voltage of the energy storage capacitor in the energy storage voltage stabilizing module 400 is large enough, the energy storage voltage stabilizing module 400 can supply power to the control module 500, so that the control module 500 can collect the current voltage of the energy storage voltage stabilizing module 400. When the value of the current voltage of the energy storage capacitor is higher than a second threshold value, the control module can drive the current acquisition module to realize a measurement function.
The control module 500 of the embodiment of the present invention includes a voltage acquisition unit and a control unit, the current acquisition unit is electrically coupled to the energy storage voltage stabilizing unit and is used for acquiring a current voltage of an energy storage capacitor in the energy storage voltage stabilizing module 400, and the control module 500 is used for acquiring the current voltage and determining whether to drive the electrical coupling of the protection module 200 and the current acquisition module 600 according to the current voltage, and determining whether to drive the electrical coupling of the energy storage voltage stabilizing module 400 and the rectification module 300 according to the current voltage.
When the value of the current voltage is higher than the second threshold, the control module 500 preferably drives the protection module 200 to electrically couple with the current collection module, drives the energy storage voltage stabilizing module to electrically disconnect from the rectification module, receives a third signal output by the current collection module, and determines the current value of the wire according to the third signal.
It should be understood that, before the energy storage voltage stabilizing module 400 is electrically coupled to the rectifying module 300, the protection module 200 is electrically coupled to the current collecting module 600 in advance, so that damage to other devices in the current sensor caused by high-energy signals transmitted by the coil can be avoided, and normal use of the current sensor is affected.
The control module 500 of the embodiment of the invention further comprises a first switch S1 and a second switch S2, wherein the first switch S1 is located between the protection module 200 and the current acquisition module and is used for controlling the coupling state of the protection module 200 and the current acquisition module, and the second switch S2 is located between the rectifying module and the energy storage voltage stabilizing module and is used for controlling the coupling state of the rectifying module and the energy storage voltage stabilizing module. The control unit can adjust the voltages of the first switch S1 and the second switch S2, and is further configured to control the voltage of the first switch S1 to make the first switch S1 be in an open state or a closed state according to the current voltage of the energy storage capacitor, and is further configured to control the voltage of the second switch S2 to make the second switch S2 be in an open state or a closed state according to the current voltage of the energy storage capacitor.
In the embodiment of the present invention, the first switch S1 and the second switch S2 are MOS switches, and specifically, the first switch S1 is a normally-on field effect transistor, and the second switch S2 is a normally-off field effect transistor. The first switch S1 and the second switch S2 may be other types of switches, which are not particularly limited herein.
The control module 500 of the embodiment of the present invention further includes a current determining unit. The current determining unit is used for determining the current of the wire according to the third signal output by the current collecting unit. In order to avoid errors, the control module only performs signal processing on the acquired third signal after a certain period of time after the energy storage voltage stabilizing module supplies power to the control module. The time period is not particularly limited here.
In some embodiments, the current determination unit may further limit the intensity of the received third signal to avoid receiving an error signal. The present invention is not particularly limited herein.
In some embodiments, the control unit is further configured to sequentially perform the steps of driving the first switch S1 to be in a closed state, driving the second switch S2 to be in an open state, acquiring a third signal output by the current acquisition module, and determining the current value of the wire according to the third signal when the current voltage of the storage capacitor is higher than the second threshold, i.e., is fully charged.
In some embodiments, the control unit is further configured to drive the second switch S2 to a closed state and drive the first switch S1 to an open state sequentially when the current voltage of the storage capacitor is lower than a third threshold, i.e. when the power is consumed.
The control module 500 of the embodiment of the present invention further includes a communication unit electrically coupled to the control unit, and the communication unit is used for transmitting the determined current value to an external device through a wireless transmission manner.
It should be appreciated that the energy storage and voltage regulation module 400 is also used to power the communication unit so that the communication unit can perform a communication function without additional power.
In order to achieve the above purpose, the embodiment of the invention further provides a current measurement method. The current measuring method is applied to the current sensor. The current measurement method comprises the following steps:
S100, an alternating magnetic field generated by a lead in an annular magnetic core is induced through a mutual inductance module, a protection module, a rectifying module and an energy storage voltage stabilizing module which are electrically coupled in sequence, and electric energy with stable voltage is stored in the energy storage voltage stabilizing module;
Specifically, before the control module participates in current measurement, the mutual inductance module, the protection module, the rectification module and the energy storage and voltage stabilization module are sequentially coupled, and the mutual inductance module is used for sensing an exchange magnetic field generated by a wire in the annular magnetic core to output a first signal, so that an energy taking function can be realized; the protection module is used for avoiding the over-high voltage of the first signal output by the mutual inductance module, further screening the first signal in advance and outputting a second signal lower than a first threshold value;
S200, supplying power to the control module through the energy storage voltage stabilizing module;
specifically, when the electric energy stored in the energy storage voltage stabilizing module reaches a certain degree, the energy storage voltage stabilizing module supplies power to the control module, and the normal operation of the control module is started.
S300, continuously collecting the current voltage of the energy storage voltage stabilizing module through the control module;
specifically, the current voltage of the energy storage voltage stabilizing module, namely the current voltage at two ends of the energy storage capacitor, is acquired through a voltage acquisition unit of the control module, and the current voltage is determined to be lower than a second threshold value.
S400, the control module judges whether the current voltage is not lower than a second threshold value, and drives the rectification module to be disconnected with the energy storage and voltage stabilization module when the current voltage is higher than the second threshold value, and the rectification module is electrically coupled with the current acquisition module, so that the current of the lead is sensed by the current acquisition module, and a third signal is output;
Specifically, when the current voltage is higher than a second threshold value, a second switch S2 between the drive rectifying module and the energy storage voltage stabilizing module is disconnected, a first switch S1 between the protection circuit and the current acquisition module is closed and connected, and then the current acquisition module is driven to acquire an alternating magnetic field of a wire, so that the function of collecting the current of the wire is realized.
S500, the control module determines the current value of the wire according to a third signal through the control unit;
specifically, the current value of the wire is determined according to the third signal and the corresponding relation between the third signal and the current value of the wire.
Further, the step may further include comparing a voltage value of the third signal, determining whether the signal is caused by an interference signal such as noise, and adopting a current value of the wire determined by the third signal when the voltage value of the third signal is within a preset range.
And S600, the control unit judges whether the current voltage is reduced to a third threshold value, and drives the rectifying module to be electrically coupled with the energy storage voltage stabilizing module when the current voltage is lower than the third threshold value, and the protection module is electrically decoupled from the current acquisition module so as to store the electric energy in the energy storage voltage stabilizing module again.
Specifically, the step is used for judging whether the electric energy of the energy storage voltage stabilizing module is near to exhaustion. The control unit judges whether the current voltage is reduced to a third threshold value, and preliminarily judges that the electric energy of the energy storage voltage stabilizing module is insufficient for supplying power to the energy storage voltage stabilizing module when the current voltage is lower than the third threshold value, and the work of current measurement is required to be interrupted, so that the energy storage voltage stabilizing module is charged, and the alternating magnetic field of the lead is converted into electric energy for storage.
The magnitude of the third threshold is not limited here. The step can also control the power supply time of the energy storage voltage stabilizing module through the control unit, and drive the rectifying module to be electrically coupled with the energy storage voltage stabilizing module when the power supply time exceeds the preset power supply time, and the protection module to be electrically decoupled from the current acquisition module so as to store the electric energy in the energy storage voltage stabilizing module again.
In the step, the driving rectifying module is decoupled from the energy storage voltage stabilizing module, the protection module is electrically coupled with the current acquisition module, and the preferred implementation step is that the driving protection module is electrically coupled with the current acquisition module, and then the driving rectifying module is decoupled from the energy storage voltage stabilizing module.
In order to achieve the above purpose, the embodiment of the invention also provides an electronic device, which comprises a current sensor, wherein the current sensor is the current sensor or is prepared by adopting the current measurement method.
The electronic equipment of the embodiment of the invention can also comprise loads such as an electric lamp, a camera and the like, and the energy storage and voltage stabilization module in the current sensor supplies power for the loads.
Therefore, compared with the prior art, the embodiment of the invention has at least the following technical effects:
the current sensor realizes the functions of CT electricity taking and current measurement through the synergistic effect of the mutual inductance module, the protection module, the current acquisition module, the rectification module, the energy storage and voltage stabilization module and the control module, avoids the repeated arrangement of the mutual inductance module and the protection module, and can greatly reduce the volume of the current sensor and reduce the equipment cost.
The foregoing is merely exemplary embodiments of the present invention and are not intended to limit the scope of the present invention, and all equivalent structural changes made by the present specification and drawings or direct/indirect application in other related technical fields are included in the scope of the present invention under the technical concept of the present invention.