A power line video monitoring device based on CT energy source

Abstract

The present invention provides a power line video monitoring device based on a CT energy source, which belongs to the field of energy source and power supply technology, and includes: an energy source coil, which is arranged in the power line and is used to induce an alternating current from the power line; a current detection circuit, which is connected to the energy source coil and is used to transmit the detected alternating current to a control circuit; a control circuit, which is respectively connected to a synchronous rectification circuit, a current detection circuit and a current limiting boost circuit, and is used to charge a rechargeable battery after rectifying and boosting the alternating current in sequence; the rechargeable battery is used to power the power line video monitoring device. The present invention induces an alternating current from the power line through an energy source coil, and performs rectification and boosting on the alternating current, so as to continuously supply power to the power line video monitoring device, eliminate the dependence on an external power source, and does not require complicated wiring, so it is suitable for deployment in various environments.

Description

Technical Field

[0001] The present invention relates to the technical field of power line monitoring, and in particular to a power line video monitoring device based on a CT energy source. Background Art

[0002] With the rapid development of urban power grids and the growing demand for electricity, the stable operation of power transmission and distribution networks has become particularly important. As a key tool to ensure power grid security and improve operation and maintenance efficiency, the power supply problem of online monitoring equipment is directly related to the reliability and stability of the monitoring system. Online monitoring equipment can detect potential safety hazards in a timely manner and improve the operation and maintenance management level of the power grid by real-time monitoring of line temperature, icing and other parameters. However, due to the complexity and particularity of the power transmission and distribution network environment, the power supply problem of online monitoring equipment has become one of the key factors restricting its application effect.

[0003] At present, for the energy supply of online monitoring equipment, most of the energy collection technologies such as solar energy, wind energy, magnetic field, and electric field are used to solve the power supply problem of online monitoring equipment on transmission lines. Among them, solar energy and wind energy have the disadvantages of being greatly affected by the region and environment, unable to work at night, and difficult to maintain. They are generally used in combination with other energy collection methods. Electric field induction energy collection technology is limited by the size of the energy collection power, and it is generally difficult to maintain the long-term operation of online monitoring equipment. Traditional current transformer (CT) energy collection is limited by the starting current and the upper limit of the working current. There is a large working dead zone, and the energy collection circuit loss is high, and the heat is serious, which restricts the application and promotion of current transformer (CT) energy collection.

[0004] In summary, studying a CT energy power supply with small starting current, high upper limit current, high efficiency and wide working range, and using this energy power supply to power the video monitoring device is of great significance for timely troubleshooting potential problems in the operation of transmission lines, determining the causes of transmission line faults, and ensuring the stable operation of the power system. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, an object of the present invention is to provide a power line video monitoring device based on a CT energy source.

[0006] To achieve the above objectives, the present invention provides the following solutions:

[0007] A power line video monitoring device based on a CT energy source, comprising:

[0008] An energy extraction coil is arranged in the power line and is used to induce an alternating current from the power line;

[0009] A current detection circuit, connected to the energy extraction coil, for transmitting the detected alternating current to the control circuit;

[0010] The control circuit is connected to the synchronous rectification circuit, the current detection circuit and the current limiting boost circuit respectively, and is used to charge the rechargeable battery after rectifying and boosting the alternating current in sequence; the rechargeable battery is used to power the power line video monitoring device.

[0011] Preferably, the energy extraction coil is a toroidal amorphous alloy magnetic core, and is wound with two sets of windings, namely winding 1 and winding 2.

[0012] Preferably, the synchronous rectification circuit comprises:

[0013] A first switch tube Q1, wherein the source of the first switch tube Q1 is connected to the first end of the winding 1, and the drain of the first switch tube Q1 is connected to the drains of the second switch tube Q2 and the third switch tube Q3 respectively; the source of the second switch tube Q2 is connected to the second end of the winding 1; the source of the third switch tube Q3 is connected to the drain of the fourth switch tube Q4;

[0014] A sixth switch tube Q6, wherein the source of the sixth switch tube Q6 is connected to the source of the fifth switch tube Q5 and the source of the fourth switch tube Q4 respectively, and the drain of the sixth switch tube Q6 is connected to the first end of the winding 1; the drain of the fifth switch tube Q5 is connected to the second end of the winding 1, and the drain of the fourth switch tube Q4 is connected to the second end of the winding 2;

[0015] The gates of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 are all controlled by the control circuit;

[0016] The seventh switch tube Q7 is connected to the first end of the winding 2 and the second end of the winding 1 respectively. The seventh switch tube Q7 is composed of two N-MOS connected in series. A varistor is connected in parallel between the gate sources of the two N-MOS, and the gates of the two N-MOS are controlled by the control circuit.

[0017] Preferably, the control circuit includes a root mean square value calculation circuit and a hysteresis comparator; after receiving the AC current, the root mean square value calculation circuit calculates the root mean square value of the AC current, and uses the root mean square value as the input of the hysteresis comparator. When the input of the hysteresis comparator is greater than the upper limit of the single winding operation, the hysteresis comparator outputs a high level, controls the seventh switch tube Q7 to turn on, and connects the winding 2 to the synchronous rectification circuit; when the input of the hysteresis comparator is less than the lower limit of the dual winding operation, the hysteresis comparator outputs a low level, controls the seventh switch tube Q7 to turn off, and disconnects the winding 2.

[0018] Preferably, the control circuit further includes a zero-crossing comparison circuit, which generates a square wave signal according to the direction of the current after receiving the alternating current, and controls the closing and conducting of the switch tube in the synchronous rectification circuit.

[0019] Preferably, when the seventh switch tube Q7 is turned off and only the winding 1 is connected to the synchronous rectification circuit, and the current flows in a positive direction, the second switch tube Q2 and the sixth switch tube Q6 are controlled to be turned off, and the first switch tube Q1 and the fifth switch tube Q5 are turned on; when the current flows in a negative direction, the first switch tube Q1 and the fifth switch tube Q5 are controlled to be turned off, and the second switch tube Q2 and the sixth switch tube Q6 are turned on;

[0020] Preferably, when the seventh switch tube Q7 is turned on, the winding 2 is connected to the synchronous rectification circuit, and the current flows in a positive direction, the third switch tube Q3 and the sixth switch tube Q6 are controlled to be turned off, and the first switch tube Q1 and the fifth switch tube Q5 are turned on; when the current flows in a negative direction, the first switch tube Q1 and the fifth switch tube Q5 are controlled to be turned off, and the third switch tube Q3 and the sixth switch tube Q6 are turned on.

[0021] Preferably, it also includes: an energy taking capacitor C 1. The energy taking capacitor C 1 is respectively connected with the synchronous rectification circuit and the current limiting boost circuit, and is used for collecting the DC current rectified by the synchronous rectification circuit, and sending the DC current to the current limiting boost circuit for boosting and then supplying the DC current to the rechargeable battery.

[0022] Preferably, it also includes: a DC-DC circuit connected to the rechargeable battery, used to boost or step down the voltage input by the rechargeable battery to power the power line video monitoring device.

[0023] Preferably, the power line video monitoring device is a camera module and a wireless communication module, and the camera module is communicatively connected to the wireless communication module for capturing videos or pictures of the environment surrounding the power line, and transmitting the captured videos or pictures to a host computer via the wireless communication module.

[0024] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0025] The present invention provides a power line video monitoring device based on a CT energy supply. Compared with the prior art, the present invention induces alternating current from the power line through an energy supply coil, and rectifies and boosts the alternating current, thereby being able to continuously supply power to the power line video monitoring device, eliminating dependence on an external power supply, and eliminating the need for complex wiring, making the device suitable for deployment in various environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0027] Figure 1 A schematic diagram of a power line video monitoring device based on a CT energy source provided by the present invention;

[0028] Figure 2 A schematic diagram of a synchronous rectification circuit provided by the present invention;

[0029] Figure 3 This is a structural diagram of the control circuit and current-limiting boost circuit provided by the present invention. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] The terms "first", "second", "third" and "fourth" in the specification and claims of the present application and the drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a series of steps, processes, methods, etc. are not limited to the listed steps, but may optionally include steps that are not listed, or may optionally include other step elements inherent to these processes, methods, products or devices.

[0033] In order to make the above-mentioned objectives, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0034] See also Figure 1-3A power line video monitoring device based on a CT energy source includes an energy-taking coil, a current detection circuit, a control circuit, a synchronous rectification circuit and a current-limiting boost circuit.

[0035] The energy extraction coil is arranged in the power line and is used to induce an alternating current from the power line; the current detection circuit is connected to the energy extraction coil and is used to transmit the detected alternating current to the control circuit; the control circuit is respectively connected to the synchronous rectification circuit, the current detection circuit and the current limiting boost circuit, and is used to rectify and boost the alternating current in sequence to charge the rechargeable battery; the rechargeable battery is used to power the power line video monitoring device. The energy extraction coil is a toroidal amorphous alloy core, and is wound with two sets of windings, namely winding 1 and winding 2.

[0036] It should be noted that the power line video monitoring device based on the CT energy source of the present invention also includes: an energy-taking capacitor C 1. Energy-taking capacitor C 1 is respectively connected to the synchronous rectification circuit and the current limiting boost circuit, and is used to collect the DC current rectified by the synchronous rectification circuit, and send the DC current to the current limiting boost circuit for boosting and then supplying it to the rechargeable battery. The DC-DC circuit is connected to the rechargeable battery, and is used to boost or reduce the voltage input by the rechargeable battery to power the power line video monitoring device. The power line video monitoring device is a camera module and a wireless communication module, and the camera module is communicatively connected to the wireless communication module, and is used to shoot videos or pictures of the environment around the power line, and transmit the shot videos or pictures to the host computer through the wireless communication module.

[0037] Furthermore, the synchronous rectification circuit includes: switch tubes Q1-Q7.

[0038] A first switch tube Q1, wherein the source of the first switch tube Q1 is connected to the first end of the winding 1, and the drain of the first switch tube Q1 is connected to the drains of the second switch tube Q2 and the third switch tube Q3 respectively; the source of the second switch tube Q2 is connected to the second end of the winding 1; the source of the third switch tube Q3 is connected to the drain of the fourth switch tube Q4;

[0039] A sixth switch tube Q6, wherein the source of the sixth switch tube Q6 is connected to the source of the fifth switch tube Q5 and the source of the fourth switch tube Q4 respectively, and the drain of the sixth switch tube Q6 is connected to the first end of the winding 1; the drain of the fifth switch tube Q5 is connected to the second end of the winding 1, and the drain of the fourth switch tube Q4 is connected to the second end of the winding 2;

[0040] The gates of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 are all controlled by the control circuit;

[0041] The seventh switch tube Q7 is connected to the first end of the winding 2 and the second end of the winding 1 respectively. The seventh switch tube Q7 is composed of two N-MOS connected in series. A varistor is connected in parallel between the gate sources of the two N-MOS, and the gates of the two N-MOS are controlled by the control circuit.

[0042] Furthermore, the control circuit includes a root mean square value calculation circuit and a hysteresis comparator; after receiving the AC current, the root mean square value calculation circuit calculates the root mean square value of the AC current and uses the root mean square value as the input of the hysteresis comparator. When the input of the hysteresis comparator is greater than the upper limit of the single winding operation, the hysteresis comparator outputs a high level, controls the seventh switch tube Q7 to turn on, and connects the winding 2 to the synchronous rectification circuit; when the input of the hysteresis comparator is less than the lower limit of the dual winding operation, the hysteresis comparator outputs a low level, controls the seventh switch tube Q7 to turn off, and disconnects the winding 2.

[0043] In an embodiment of the present invention, the control circuit further includes a zero-crossing comparison circuit, which generates a square wave signal according to the current flow direction after receiving the AC current, and controls the closing and conducting of the switch tube in the synchronous rectification circuit. When the seventh switch tube Q7 is turned off and only the winding 1 is connected to the synchronous rectification circuit, and the current flow direction is positive, the second switch tube Q2 and the sixth switch tube Q6 are controlled to be turned off, and the first switch tube Q1 and the fifth switch tube Q5 are turned on; when the current flow direction is negative, the first switch tube Q1 and the fifth switch tube Q5 are controlled to be turned off, and the second switch tube Q2 and the sixth switch tube Q6 are turned on; when the seventh switch tube Q7 is turned on, the winding 2 is connected to the synchronous rectification circuit, and the current flow direction is positive, the third switch tube Q3 and the sixth switch tube Q6 are controlled to be turned off, and the first switch tube Q1 and the fifth switch tube Q5 are turned on; when the current flow direction is negative, the first switch tube Q1 and the fifth switch tube Q5 are controlled to be turned off, and the third switch tube Q3 and the sixth switch tube Q6 are turned on.

[0044] The present invention induces AC current from the power line through the energy taking coil, and rectifies and boosts the AC current, so as to continuously supply power to the power line video monitoring device, eliminate the dependence on external power supply, do not require complicated wiring, and is suitable for deployment in various environments.

[0045] The power extraction process of the present invention is further described below in conjunction with specific embodiments:

[0046] See also Figure 1 , Figure 1This is a schematic diagram of the structure of a CT power-taking video monitoring device using a synchronous rectification structure. Based on the principle of electromagnetic induction, the amorphous alloy energy-taking coil induces AC current from the power line and injects energy into the rectification circuit; the current detection circuit is used to monitor the direction of the input current and the effective value of the input current; the synchronous rectification circuit closes and turns on the switch tubes of different bridge arms according to the action instructions of the current detection circuit, and rectifies the input current. MOS tubes are used as switch tubes, which have small conduction losses and low heat generation; the control circuit determines whether to switch the winding according to the current current size, and controls the conduction of the switch tube in the synchronous rectification circuit according to the direction of the input current; the energy-taking capacitor C 1Store the rectified DC current energy and power the previous circuit modules; the current limiting boost circuit module takes the energy from the capacitor C 1 voltage is boosted and supplied to the rechargeable battery C S ; The DC-DC circuit will recharge the battery C S The voltage is stepped up or down to power the camera module and the wireless communication module; the camera module and the wireless communication module complete the video capture and wireless transmission of the environment around the power line.

[0047] Figure 1 The amorphous alloy energy harvesting coil in the circuit adopts a circular amorphous alloy core, which is wound with two sets of windings and has two current working ranges. The relative magnetic permeability of the high permeability core at an industrial frequency of 50Hz is greater than 120,000. When the current in the power line is small, it can induce current on the secondary side to harvest energy. By optimizing the relationship between the number of turns of winding 1 and the starting current, the optimal number of turns is selected for the current core, which can reduce the starting current of the energy harvesting circuit to 3A. The two sets of windings of the high permeability energy harvesting coil are divided into winding 1 and winding 2. Winding 1 remains connected to the synchronous rectification module, and winding 2 determines whether to connect to the synchronous rectification module according to the secondary current. The number of turns n1 of winding 1 is small, and it is used in working environments with small current in the power line. The number of turns n2 of winding 2 is 3 times the number of turns of winding 1. When winding 2 is not connected to the energy harvesting circuit, the current in the power line I 1 is the current flowing through the secondary winding I 2, I 1 and I 2Satisfy the transformation ratio relationship:

[0048]

[0049] When the current in the power line I 1 increases, the current flowing through the secondary winding I 2 increases accordingly; when I 2 exceeds the set threshold, winding 2 is connected to the energy-taking circuit, and the number of turns of the secondary winding increases to 4 times the original. I1 and I 2Satisfy the transformation ratio relationship:

[0050]

[0051] Current flowing through the secondary winding I 2 is reduced to 1 / 4 of the original. When only winding 1 is connected to the energy-taking circuit, the operating current range of the energy-taking circuit is 3A-300A; when winding 2 is connected to the energy-taking circuit, the operating current range of the energy-taking circuit is 3A-1200A, and the operating current range of the energy-taking circuit is greatly improved.

[0052] Figure 1 The control circuit in the embodiment has a built-in hysteresis comparator circuit. The control circuit compares the secondary current root mean square value calculated by the current detection circuit with the high threshold set in the hysteresis comparator circuit to determine whether the current current exceeds the operating current range of winding 1. If so, a control signal is generated to drive the switch tube in the synchronous rectification circuit to turn on, and connect winding 2 to the energy extraction circuit. When the secondary current is less than the low threshold set in the hysteresis comparator circuit, it means that the current secondary current meets the single winding operating current range of winding 1, and the control circuit generates a drive signal to control the switch tube in the synchronous rectification circuit to turn off, and winding 2 is cut out of the energy extraction circuit.

[0053] Figure 1 Energy harvesting capacitor C 1 is used to collect the DC current rectified by the synchronous rectification circuit and to supply power to the current detection circuit, control circuit, synchronous rectification circuit and current limiting boost circuit of the previous stage. C 1 voltage is boosted and supplied to the rechargeable battery C S ; The DC-DC circuit will recharge the battery C S The voltage is stepped up or down to power the camera module and the wireless communication module; the camera module and the wireless communication module complete the video capture and wireless transmission of the environment around the power line.

[0054] See also Figure 2 , Figure 2 This is the schematic diagram of the synchronous rectification circuit. Q1-Q7 are N-MOS with low conduction loss and low heat generation. Q7 is composed of two N-MOS in series. The gate is controlled by a unified signal. A varistor is connected in parallel between the gate and the source to prevent the breakdown of the N-MOS due to overvoltage caused by the switching action. The switch tube drive signal of the synchronous rectification circuit comes from the current detection circuit and the control circuit. When only winding 1 is connected to the energy extraction circuit, Q7 tube is turned off to Figure 2The mark in the middle is for reference. When the current flows in a positive direction, Q2 and Q6 are turned off, and Q1 and Q5 are turned on; when the current flows in a negative direction, Q1 and Q5 are turned off, and Q2 and Q6 are turned on. When the secondary current is too large, the control circuit drives Q7 to turn on, and winding 2 is connected to the energy-taking circuit; when the current flows in a positive direction, Q3 and Q6 are turned off, and Q1 and Q5 are turned on; when the current flows in a negative direction, Q1 and Q5 are turned off, and Q3 and Q6 are turned on.

[0055] See also Figure 3 , Figure 3 This is a control circuit and a current-limiting boost circuit structure diagram. The control circuit obtains a square wave signal by performing a zero-crossing comparison on the sinusoidal current signal 2 transmitted by the current detection circuit. The square wave signal is transmitted to the switch tube driver chip that needs to be turned off through inversion, and then transmitted to the switch tube driver chip that needs to be turned on through a high-level delay. The introduction of the turn-on dead time can prevent the MOS tube in the same bridge arm from being directly turned on and short-circuited. The sinusoidal current signal transmitted by the current detection circuit is used as the input of the hysteresis comparator after passing through the RMS value calculation circuit of the control circuit. V I , and set the threshold V ref1 For comparison, when the secondary current is greater than the upper limit of the single winding operation, V I Greater than V ref1 High threshold, the comparator outputs a high level, Q7 is turned on, winding 2 is connected to the energy-taking circuit, and the set threshold value V of the hysteresis comparator ref1 When the secondary current is less than the lower limit of the dual winding operation, V I Less than V ref1 Low threshold, comparator output low level, Q7 tube turned off, winding 2 disconnected, hysteresis comparator set threshold V ref1 The above process realizes the winding switching function of the energy taking coil.

[0056] See also Figure 3 , the control circuit simultaneously monitors the energy-taking capacitor C 1 Voltage V C1 and rechargeable batteries C S Voltage V Cs , V C1 After being inverted by the subtraction circuit, V C2 ,in, V C2 = Vref2 - V C1 , connected to the A- pin of the single-pole double-throw switch; V Cs Connect to the A+ pin of a single-pole double-throw switch. V Cs The reference value set by the hysteresis comparator V ref3 Comparison determines the output of the single-pole double-throw switch. V Cs Greater than V ref3 When the threshold is high, the comparator outputs a high level, and the single-pole double-throw switch outputs the signal connected to the A+ pin, that is, V Cs ;when V Cs Less than V ref3 When the threshold is low, the comparator outputs a low level, and the single-pole double-throw switch outputs the signal connected to the A- pin, that is, V C2 The output of the single-pole double-throw switch is connected to the feedback pin FB of the current-limiting boost circuit, that is, the input voltage or output voltage of the current-limiting boost circuit is used as the feedback value for voltage regulation. V Cs Greater than V ref3 When the threshold is high, the signal connected to the FB pin is V Cs , that is, to stabilize the output voltage of the current limiting boost circuit. V Cs Less than V ref3 When the threshold is low, the signal connected to the FB pin is V C2 , that is, to stabilize the input voltage of the current limiting boost circuit.

[0057] The FB pin input signal of the current limiting boost circuit is connected to the negative terminal of the PI regulator and the internal reference signal V ref4 Perform PI regulation control, output a given current signal and act on the PWM generation circuit; the current transformer obtains the current value flowing through the inductor L I L , the current value is consistent with the set reference current value I lim Compare and act on the PWM generation circuit. I L Greater than a given current signal or I limWhen the PWM generation circuit is turned on, the trigger inside the PWM generation circuit will be set to control the output of the PWM generation circuit and act on the switch tube of the boost circuit to limit the current value flowing through the inductor L. I L Since the inductor current cannot change suddenly, the inductor is charged and discharged periodically. At this time, the voltage signal at the FB terminal is stable, realizing the voltage regulation control of the input voltage or output voltage.

[0058] According to the specific embodiment of the present invention, the present invention provides the following effects:

[0059] 1. The energy-taking magnetic core is made of toroidal high-permeability material, which can take energy under low current conditions. The energy-taking magnetic core has two windings, which enables the energy-taking circuit to have two working current ranges. It can work well under high and low current conditions of the power line, greatly broadening the working current range of CT energy taking.

[0060] 2. The energy-taking circuit uses a synchronous rectification circuit. The current detection circuit determines the current flow direction and controls the MOS tube to turn off and on for synchronous rectification. The conduction loss of this solution is much smaller than that of diode rectification, and the MOS tube does not have serious heating under high current conditions.

[0061] 3. The control circuit of the energy-taking circuit determines whether to switch the windings according to the current secondary current. When the current exceeds the working current range of a single winding, the winding 2 with more turns is connected to the energy-taking circuit to reduce the current secondary current, so that the energy-taking circuit can work under the condition of large current of the power line; when the secondary current is small, the control circuit can cut the winding 2 out of the energy-taking circuit in time, so that the energy-taking circuit can work well under the condition of small current;

[0062] 4. The energy-harvesting circuit adopts a current-limiting boost circuit, which can limit the input current of the boost circuit, thereby improving the dynamic response speed of the energy-harvesting power supply; the input voltage or output voltage of the current-limiting boost circuit is stabilized and controlled through the feedback end of the current-limiting boost circuit, thereby improving the efficiency of the energy-harvesting circuit.

[0063] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the method disclosed in the embodiment, since it corresponds to the device disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the device part description.

[0064] The principles and implementation methods of the present invention are described in this article using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A power line video monitoring device based on CT energy source, characterized in that: include: An energy extraction coil is arranged in the power line and is used to induce an alternating current from the power line; A current detection circuit, connected to the energy extraction coil, for transmitting the detected alternating current to the control circuit; The control circuit is connected to the synchronous rectification circuit, the current detection circuit and the current limiting boost circuit respectively, and is used to charge the rechargeable battery after rectifying and boosting the alternating current in sequence; the rechargeable battery is used to power the power line video monitoring device; The energy extraction coil is a toroidal amorphous alloy magnetic core, and is wound with two sets of windings, namely winding (1) and winding (2); The synchronous rectification circuit comprises: A first switch tube (Q1), wherein a source of the first switch tube (Q1) is connected to a first end of a winding (1), and a drain of the first switch tube (Q1) is respectively connected to drains of a second switch tube (Q2) and a third switch tube (Q3); a source of the second switch tube (Q2) is connected to a second end of the winding (1); and a source of the third switch tube (Q3) is connected to a drain of a fourth switch tube (Q4); a sixth switch tube (Q6), wherein a source of the sixth switch tube (Q6) is respectively connected to the source of the fifth switch tube (Q5) and the source of the fourth switch tube (Q4), and a drain of the sixth switch tube (Q6) is connected to the first end of the winding (1); a drain of the fifth switch tube (Q5) is connected to the second end of the winding (1), and a drain of the fourth switch tube (Q4) is connected to the second end of the winding (2); The gates of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3), the fourth switch tube (Q4), the fifth switch tube (Q5) and the sixth switch tube (Q6) are all controlled by a control circuit; The seventh switch tube (Q7) is connected to the first end of the winding (2) and the second end of the winding (1) respectively, and the seventh switch tube (Q7) is composed of two N-MOSs connected in series, a varistor is connected in parallel between the gate sources of the two N-MOSs, and the gates of the two N-MOSs are controlled by a control circuit; The FB pin of the current limiting boost circuit inputs the signal from the control circuit to the negative terminal of the PI regulator and is connected to the internal reference signal V ref4 Perform PI regulation control, output a given current signal and act on the PWM generation circuit; the current transformer obtains the current value I flowing through the inductor L , the current value is equal to the set reference current value I lim Compare and act on the PWM generation circuit, when I L Greater than a given current signal or I lim When the PWM generation circuit is turned on, the trigger inside the PWM generation circuit will be set to control the output of the PWM generation circuit and act on the switch tube of the current limiting boost circuit to limit the current value I flowing through the inductor L. L .

2. A power line video monitoring device based on CT energy source as claimed in claim 1, characterized in that: The control circuit includes a root mean square value calculation circuit and a hysteresis comparator; After receiving the AC current, the RMS value calculation circuit calculates the RMS value of the AC current and uses the RMS value as the input of the hysteresis comparator. When the input of the hysteresis comparator is greater than the upper limit value of the single winding operation, the hysteresis comparator outputs a high level, controls the seventh switch tube (Q7) to be turned on, and connects the winding (2) to the synchronous rectification circuit; when the input of the hysteresis comparator is less than the lower limit value of the dual winding operation, the hysteresis comparator outputs a low level, controls the seventh switch tube (Q7) to be turned off, and disconnects the winding (2).

3. A power line video monitoring device based on CT energy source as claimed in claim 2, characterized in that: The control circuit also includes a zero-crossing comparison circuit. After receiving the alternating current, the zero-crossing comparison circuit generates a square wave signal according to the direction of the current to control the closing and conducting of the switch tube in the synchronous rectification circuit.

4. A power line video monitoring device based on CT energy source as claimed in claim 3, characterized in that: When the seventh switch tube (Q7) is turned off and only the winding (1) is connected to the synchronous rectification circuit, and the current flow direction is positive, the second switch tube (Q2) and the sixth switch tube (Q6) are controlled to be turned off, and the first switch tube (Q1) and the fifth switch tube (Q5) are turned on; when the current flow direction is negative, the first switch tube (Q1) and the fifth switch tube (Q5) are controlled to be turned off, and the second switch tube (Q2) and the sixth switch tube (Q6) are turned on.

5. A power line video monitoring device based on CT energy source as claimed in claim 4, characterized in that: When the seventh switch tube (Q7) is turned on, the winding (2) is connected to the synchronous rectification circuit, and the current flows in a positive direction, the third switch tube (Q3) and the sixth switch tube (Q6) are controlled to be turned off, and the first switch tube (Q1) and the fifth switch tube (Q5) are controlled to be turned off, and the third switch tube (Q3) and the sixth switch tube (Q6) are controlled to be turned on; when the current flows in a negative direction, the first switch tube (Q1) and the fifth switch tube (Q5) are controlled to be turned off, and the third switch tube (Q3) and the sixth switch tube (Q6) are controlled to be turned on.

6. The power line video monitoring device based on CT energy source according to claim 1, characterized in that: The invention also includes: an energy collection capacitor (C1), which is respectively connected to the synchronous rectification circuit and the current limiting boost circuit, and is used to collect the direct current rectified by the synchronous rectification circuit, and send the direct current to the current limiting boost circuit for boosting and then supplying the direct current to the rechargeable battery.

7. The power line video monitoring device based on CT energy source according to claim 1, characterized in that: Also includes: The DC-DC circuit is connected to the rechargeable battery and is used to boost or reduce the voltage input by the rechargeable battery to supply power to the power line video monitoring device.

8. The power line video monitoring device based on CT energy source according to claim 1, characterized in that: The power line video monitoring device comprises a camera module and a wireless communication module. The camera module is communicatively connected to the wireless communication module for capturing videos or pictures of the environment surrounding the power line, and transmitting the captured videos or pictures to a host computer via the wireless communication module.

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