CN-121984149-A - CT induction power taking circuit and method

CN121984149ACN 121984149 ACN121984149 ACN 121984149ACN-121984149-A

Abstract

The invention discloses a CT induction power taking circuit and a method, wherein the circuit comprises a voltage doubling rectifying module, an energy storage module and a voltage monitoring output module which are sequentially connected. The voltage monitoring output module cooperatively controls the architecture of a low-dropout linear voltage regulator through the first voltage monitoring chip and the second voltage monitoring chip, and logically combines output signals of the first voltage monitoring chip and the second voltage monitoring chip through the voltage dividing unit. The method realizes the automatic switching of four stages of system power-on, power supply maintenance, safety turn-off and cycle restart through the circuit. The low-dropout linear voltage regulator has the core that when the main energy storage voltage is insufficient, the energy storage of the auxiliary energy storage capacitor is utilized and the power supply is maintained by the second voltage monitoring chip, and the low-dropout linear voltage regulator is reliably turned off until the voltages of the auxiliary energy storage capacitor and the second voltage monitoring chip are insufficient, so that the problem of dead zone when the low-dropout linear voltage regulator is repeatedly started and stopped near the critical voltage in the prior art is thoroughly solved. The invention has the advantages of low induction power-taking starting current, high power-taking efficiency and stable and reliable work.

Inventors

CHEN KAN
XU BINGHAN
JIN YUYI
WANG SHIHUI
CHEN GUOWANG
ZHANG YUANJIE
WU CHEN
JIANG JIANMEI

Assignees

江苏安科瑞电器制造有限公司
安科瑞电气股份有限公司
江苏安科瑞微电网研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20260126

Claims (10)

1. The CT induction power taking circuit is characterized by comprising a voltage doubling rectifying module, an energy storage module and a voltage monitoring output module which are sequentially connected; The voltage monitoring output module comprises a first voltage monitoring chip (IC 2), a second voltage monitoring chip (IC 3), a voltage dividing unit and a low-dropout linear voltage regulator (IC 1), wherein the output ends of the first voltage monitoring chip (IC 2) and the second voltage monitoring chip (IC 3) are connected to an enabling input End (EN) of the low-dropout linear voltage regulator through the voltage dividing unit, the output end of the low-dropout linear voltage regulator (IC 1) is connected with the ground in parallel through a fourth filter capacitor (C4) and a third energy storage capacitor (C3), and the positive electrode of the third energy storage capacitor (C3) is connected to the input end of the second voltage monitoring chip (IC 3); A transient suppression diode (D2) is connected IN parallel between the input end of the voltage doubling rectifying module and the output end (AC+, AC-) of the CT coil, and the output end of the energy storage module is respectively connected to the first voltage monitoring chip and the power input ends (VIN, IN) of the low-dropout linear voltage regulator.
2. The CT sensing power extraction circuit of claim 1, wherein the output of the voltage doubler rectifier module is coupled to the input of the energy storage module via a zener diode (D3).
3. The CT sensing circuit of claim 1, wherein the voltage doubler rectifier module comprises a first set of rectifier diodes (D1, D4), a second set of rectifier diodes (D5, D6), a first set of voltage doubler capacitors (C1, C2), and a second set of voltage doubler capacitors (C9, C10); when the alternating voltage induced by the CT coil is in a first polarity half cycle, the voltage charges a first capacitor (C1) and a second capacitor (C2) through a first diode (D1) and a fourth diode (D4) respectively; when the alternating voltage induced by the CT coil is in a second-stage half cycle with the polarity opposite to the first polarity, the CT coil induced voltage, the first capacitor (C1) and the storage voltage of the second capacitor (C2) charge a ninth capacitor (C9) and a tenth capacitor (C10) respectively through a fifth diode (D5) and a sixth diode (D6); The first set of voltage-multiplying capacitors (C9, C10) is connected in series with the second set of voltage-multiplying capacitors (C1, C2).
4. The CT sensing circuit of claim 1 wherein the energy storage module comprises a plurality of electrolytic capacitors (C5, C6, C7, C8) connected in parallel, the cathodes of each electrolytic capacitor being commonly grounded.
5. The CT sensing circuit of claim 4, wherein the input terminal (VIN) of the first voltage monitoring chip (IC 2) is connected to a common node of the positive electrode of the electrolytic capacitor in the energy storage module.
6. The CT sensing circuit as claimed in claim 1, wherein the voltage dividing unit comprises a first voltage dividing resistor (R1) and a second voltage dividing resistor (R2) which are connected in series, one end of the first voltage dividing resistor (R1) is connected to the output end of the first voltage monitoring chip (IC 2), one end of the second voltage dividing resistor (R2) is connected to the output end of the second voltage monitoring chip (IC 3), the other end of the first voltage dividing resistor (R1) and the other end of the second voltage dividing resistor (R2) are commonly connected to form a common connection point, and the common connection point is connected to the enabling input End (EN) of the low-dropout linear voltage regulator (IC 1).
7. A power extraction method based on the CT induction power extraction circuit according to any one of claims 1 to 6, comprising the steps of: When the direct current voltage of the positive electrode of the energy storage module is larger than the starting threshold value of a first voltage monitoring chip (IC 2), the first voltage monitoring chip (IC 2) outputs a high-level signal and transmits the high-level signal to an enabling input End (EN) of a low-voltage-difference linear voltage stabilizer (IC 1) through a first voltage dividing resistor (R1), the low-voltage-difference linear voltage stabilizer (IC 1) is started and supplies power for a later-stage load, and meanwhile, a third auxiliary energy storage capacitor (C3) is charged after being filtered through a fourth filter capacitor (C4); S2, maintaining the power supply stage, namely stopping outputting a high-level signal by the first voltage monitoring chip (IC 2) when the voltage of the energy storage module is reduced to be lower than the starting threshold value of the first voltage monitoring chip (IC 2), and outputting a high-level signal to a public connection point of the voltage dividing unit by the second voltage monitoring chip (IC 3) to continuously provide an effective level for an enable input End (EN) of the low-dropout linear regulator (IC 1) to maintain the low-dropout linear regulator (IC 1) to work if the voltage of the third auxiliary energy storage capacitor (C3) is higher than the maintaining threshold value of the second voltage monitoring chip (IC 3); S3, a safe turn-off stage, wherein when the voltage of the energy storage module is lower than the turn-on threshold of the first voltage monitoring chip (IC 2) and the voltage of the third auxiliary energy storage capacitor (C3) is simultaneously lower than the maintenance threshold of the second voltage monitoring chip (IC 3), the voltage of the enabling end of the low-dropout linear voltage regulator (IC 1) is turned off; And S4, in a cycle restarting stage, after the system is turned off, the CT coil continues to charge the energy storage module, and when the voltage of the CT coil reaches the starting threshold value of the first voltage monitoring chip (IC 2) again, the step S1 is repeated.
8. The method of claim 7, wherein the step S1 further comprises clamping the AC voltage induced by the CT coil with a transient suppression diode (D2) and transmitting the AC voltage to the voltage doubling rectifying module.
9. The method according to claim 7, wherein the step of boosting the voltage by the voltage doubling rectifying module specifically includes charging the first set of voltage doubling capacitors (C9, C10) through the first set of rectifying diodes (D5, D6) in a positive half cycle of the ac voltage, charging the second set of voltage doubling capacitors (C1, C2) through the second set of rectifying diodes (D1, D4) in a negative half cycle of the ac voltage, and superposing the voltages of the first set of voltage doubling capacitors (C9, C10) and the second set of voltage doubling capacitors (C1, C2) in series and outputting the superposed voltages.
10. The power extraction method according to claim 7, characterized in that the turn-on threshold of the first voltage monitoring chip (IC 2) is higher than the sustain threshold of the second voltage monitoring chip (IC 3).

Description

CT induction power taking circuit and method Technical Field The invention relates to the technical field of power equipment power acquisition, in particular to a CT induction power acquisition circuit and a CT induction power acquisition method. Background In a power system, it is important to monitor the temperature of key parts such as a switch cabinet, a bus joint and the like on line. The wireless temperature sensor is widely applied because of the advantages of convenient installation, no wiring and the like. Such sensors typically need to operate on the high voltage side for long periods of time, and the power supply problem is a major challenge. The potential safety hazard exists when the power is directly taken from the high-voltage line, and the problems of inconvenient maintenance and replacement, limited service life and the like are faced when the battery is used. Thus, inductive power harvesting from primary side current through a current transformer is an ideal solution. The principle is that weak electric energy is obtained from a CT coil wrapped on a bus by electromagnetic induction, and the weak electric energy is processed to supply power for a sensor. This way is safe, isolated and requires no additional power supply. The existing CT induction power-taking circuit has the defects that firstly, the initial voltage and the current induced by CT are very weak, the traditional circuit needs higher starting current to establish working voltage, so that equipment cannot be started when bus current is smaller, and secondly, in the working process, if the power-taking power is temporarily insufficient due to the fluctuation of the bus current or the change of load, a power supply circuit easily enters a dead zone state of repeated on and off, and the system is extremely unstable and even completely fails. This severely limits the reliability and range of applications of CT power acquisition techniques. Therefore, a CT induction power-taking circuit and method with low starting current, high power-taking efficiency, and stable operation in case of energy fluctuation, and no dead zone are needed. Disclosure of Invention The invention aims to overcome the defects in the prior art and provides a CT induction power taking circuit and a CT induction power taking method which are low in starting current, high in efficiency and stable and reliable in operation. In order to achieve the above purpose, the invention adopts the following technical scheme: In a first aspect, the invention provides a CT induction power taking circuit, which comprises a voltage doubling rectifying module, an energy storage module and a voltage monitoring output module; The voltage monitoring output module comprises a first voltage monitoring chip, a second voltage monitoring chip, a voltage dividing unit and a low-dropout linear voltage regulator, wherein the output ends of the first voltage monitoring chip and the second voltage monitoring chip are connected to the enabling input end of the low-dropout linear voltage regulator through the voltage dividing unit, the output end of the low-dropout linear voltage regulator is connected with the ground in parallel through a fourth filter capacitor and a third energy storage capacitor, and the positive electrode of the third energy storage capacitor is connected to the input end of the second voltage monitoring chip; The output end of the energy storage module is respectively connected to the first voltage monitoring chip and the power input end of the low-dropout linear voltage regulator. Further, the output end of the voltage doubling rectifying module is connected to the input end of the energy storage module through a voltage stabilizing diode. Further, the voltage doubling rectifying module comprises a first group of rectifying diodes, a second group of rectifying diodes, a first group of voltage doubling capacitors and a second group of voltage doubling capacitors; The first group of rectifying diodes comprise a first diode and a fourth diode, the second group of rectifying diodes comprise a fifth diode and a sixth diode, the first group of voltage doubling capacitors comprise a first capacitor and a second capacitor, and the second group of voltage doubling capacitors comprise a ninth capacitor and a tenth capacitor; the anodes of the fifth diode and the sixth diode are respectively connected to the AC-end of the CT coil through the first capacitor and the fourth capacitor, and the cathodes are respectively connected to the AC-end of the CT coil through the ninth capacitor and the tenth capacitor; when the alternating voltage induced by the CT coil is in a first polarity half cycle, namely the AC+ end is positive, and the AC-end is negative, the current charges the first capacitor and the second capacitor through the first diode and the fourth diode respectively; The alternating voltage induced by the CT coil is in a second-stage half cycle with the polarity opposite to that