CT energy-taking power supply circuit with self-adaptive output power

Abstract

The invention provides a CT energy-taking power supply circuit with self-adaptive output power, and relates to the technical field of power electronics, and the circuit comprises an energy-taking input protection module which is used for obtaining alternating current from a CT induction coil; the rectifying and filtering module is used for rectifying alternating current into pulsating direct current, and the pulsating direct current is smoothed by a filtering capacitor and then provides stable direct-current bus voltage for a post-stage conversion circuit; the DC-DC conversion module is used for efficiently converting the direct-current bus voltage into isolated direct-current voltage suitable for a load; the multi-stage adaptive feedback module is used for dynamically adjusting an output current reference through multi-stage voltage comparison and an optocoupler feedback network, so that the output power is adaptively matched with the CT energy taking size; and the direct current output module is used for rectifying and filtering the converted voltage and providing stable and low-ripple direct current output. According to the technical scheme, the output power is self-adapted according to the magnitude of the CT output electric energy, and the reliability and stability of power supply of the load equipment are improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power electronics, and particularly relates to a CT power-taking power supply circuit with adaptive output power. BACKGROUND

[0002] With the development of smart grids, the monitoring and control requirements of medium and high voltage power distribution equipment are increasing; however, the power supply of monitoring and control equipment has been a difficult problem. Medium and high voltage monitoring and control equipment cannot be conveniently connected to the mains, battery power supply has the problems of short time and difficulty in replacement, and solar power taking has the problem of being greatly affected by weather. Under this background, CT passive power taking becomes a necessity. CT power taking has many advantages as a new type of power taking method, and the disadvantage is obvious, that is, the power taken is affected by the bus current. When the bus current is large, the power taken is large, and when the bus current is small, the power taken is small. The problem in actual application is that electric energy is wasted during the power consumption peak, and the electric energy is insufficient to support the normal work of the monitoring and control equipment during the power consumption valley. SUMMARY

[0003] The novel purpose of the application is to solve the problems of energy waste and power supply interruption caused by CT power taking fluctuation with bus current, and provide a CT power-taking power supply circuit with adaptive output power.

[0004] The above purpose of the application is realized by the following technical scheme: The circuit comprises a power-taking input protection module, a rectification and filtering module, a DC-DC conversion module, a battery management module, a multi-stage adaptive feedback module and a direct current output module; the power-taking input protection module, the rectification and filtering module, the DC-DC conversion module, the battery management module, the multi-stage adaptive feedback module and the direct current output module are electrically connected; The power-taking input protection module is used for obtaining alternating current from a CT induction coil; The rectification and filtering module is used for rectifying the alternating current into pulsating direct current, and providing a stable direct current bus voltage for the subsequent conversion circuit after smoothing by a filtering capacitor; The DC-DC conversion module is used for efficiently converting the direct current bus voltage into an isolated direct current voltage suitable for the load; The battery management module is used for storing the excess energy to the battery when the CT energy is excessive, and seamlessly supplying power to the load by the battery when the CT energy is insufficient; The multi-stage adaptive feedback module is used for dynamically adjusting the output current reference through a multi-stage voltage comparison and optocoupler feedback network, so that the output power is adaptively matched with the CT power taking size; The direct current output module is used for rectifying and filtering the converted voltage, and providing stable and low-ripple direct current output.

[0005] Optionally, the first input terminal L1 of the energy input protection module is connected to one end of the pressure sensitive resistor RV1, the No. 2 pin of the first thyristor SCR1, one end of the first current limiting resistor R8 and one end of the resistor R10, respectively; the second input terminal N1 is connected to the other end of the pressure sensitive resistor RV1, the No. 1 pin of the first thyristor SCR1, one end of the capacitor C2 and one end of the capacitor C4, respectively; one end of the capacitor C4 is connected to the second input terminal of the common mode inductor L1; One end of the transient suppression diode D1 is connected to the gate of the first thyristor SCR1, and the other end is connected to the other end of the first current limiting resistor R8 and the other end of the capacitor C2; the other end of the capacitor C4 is connected to the other end of the resistor R10 and the first input terminal of the common mode inductor L1, respectively; The output terminal first pin of the common mode inductor L1 is connected to the first alternating current input terminal of the rectifier bridge DB1 of the rectification and filtering module, and the output terminal second pin of the common mode inductor L1 is connected to the second alternating current input terminal of the rectifier bridge DB1; The direct current positive output terminal of the rectifier bridge DB1 is connected to the positive pole of the first filtering capacitor E1, and together forms a first direct current node VIN+; The direct current negative output terminal of the rectifier bridge DB1 is connected to the negative pole of the first filtering capacitor E1, and together forms a first common ground GND1.

[0006] Optionally, the DC-DC conversion module includes a PWM control chip U5, a switch tube Q1 and an isolation transformer T1; The first direct current node VIN+ is connected to the first end of the primary winding of the isolation transformer T1, one end of the absorption capacitor C8, one end of the resistor R33, one end of the resistor R34, one end of the resistor R35 and one end of the resistor R19, respectively; The other end of the absorption capacitor C8, the other end of the resistor R33, the other end of the resistor R34 and the other end of the resistor R35 are connected to the cathode of the absorption diode D3; The third end of the primary winding of the isolation transformer T1 is connected to the anode of the absorption diode D3 and the drain of the switch tube Q1, respectively; The source of the switch tube Q1 is connected to one end of the sampling resistor RS1, one end of the second current limiting resistor R25 and one end of the resistor R27, respectively; The gate of the switch tube Q1 is connected to the other end of the resistor R27 and one end of the resistor R21, respectively; The other end of the resistor R21 is connected to the No. 6 pin of the PWM control chip U5; the other end of the resistor R19 is connected to one end of the resistor R20; the other end of the resistor R20 is connected to the No. 5 pin of the PWM control chip U5.

[0007] Optionally, the battery management module includes an anti-inversion diode D2 and an energy storage capacitor E2; The anode of the reverse flow prevention diode D2 is connected to the direct current voltage output positive terminal CV+, and the cathode is connected to the 5th pin of the PWM control chip U5 and the positive pole of the energy storage capacitor E2; the negative pole of the energy storage capacitor E2 is grounded.

[0008] Optionally, the 5th pin of the PWM control chip U5 is also connected to an auxiliary power supply circuit; The auxiliary power supply circuit comprises an auxiliary winding rectifier diode D4 and an auxiliary power supply filter capacitor E3. The third end of the auxiliary winding of the isolation transformer T1 is connected to the anode of the auxiliary winding rectifier diode D4 through the resistor R36; the cathode of the auxiliary winding rectifier diode D4 is connected to the positive pole of the auxiliary power supply filter capacitor E3 and the anode of the reverse flow prevention diode D2, respectively. Optionally, the fifth end of the auxiliary winding of the isolation transformer T1 and the negative pole of the auxiliary power supply filter capacitor E3 are grounded.

[0009] The multi-stage adaptive feedback module comprises an input voltage sampling chain, a multi-stage voltage comparator chain and an adjustable reference circuit. The input voltage sampling chain, the multi-stage voltage comparator chain and the adjustable reference circuit are sequentially connected in order. The input voltage sampling chain is composed of a plurality of voltage dividing resistors R1, R2, R3, R4, R5, R6, R7, R9, R11, R12, R13, R14, R15, R16, R17 and R18 connected in series between the first direct current node VIN+ and the first common ground GND1, forming a plurality of voltage dividing nodes. The multi-stage voltage comparator chain comprises at least two parallel voltage reference source chips U1, U2, U3 and U4. The reference input end REF of each voltage reference source chip is connected to one voltage dividing node of the input voltage sampling chain, and the cathodes of the voltage reference source chips U1, U2, U3 and U4 are respectively connected to the anodes of the light emitting diodes in the feedback optocouplers U7, U8, U9 and U10. The cathodes of the light emitting diodes in each feedback optocoupler U7, U8, U9 and U10 are grounded. The light emitting diodes of the feedback optocouplers U7, U8, U9 and U10 are respectively connected in parallel with the resistors R29, R30, R31 and R32. The anodes of the light emitting diodes of the feedback optocouplers U7, U8, U9 and U10 are respectively connected to one end of the resistors R28, R26, R24 and R23; the other ends of the resistors R28, R26, R24 and R23 are connected to the direct current voltage output positive terminal CV+. The adjustable reference circuit comprises a first reference resistor R51 and a second reference resistor R52 connected in series. One end of the first reference resistor R51 is connected to the DC voltage output negative terminal G1, and the other end of the first reference resistor R51 is connected to one end of the second reference resistor R52; the other end of the second reference resistor R52 is connected to pin 3 of the operational amplifier U11; The collector of the phototriode in the feedback optical coupler U7, U8, U9 and U10 is connected to the two ends of the second reference resistor R52 through an adjusting branch composed of four groups of adjusting resistors R38 and R43, R39 and R44, R40 and R45, and R41 and R46 connected in series.

[0010] Optionally, the DC output module comprises a secondary side rectification and filtering circuit and a constant current control circuit; The secondary side rectification and filtering circuit is connected to the constant current control circuit; The secondary side rectification and filtering circuit specifically comprises: The tenth end of the secondary side winding of the isolation transformer T1 is connected to the anode of the output rectification diode D7; The cathode of the output rectification diode D7 is connected to one end of the output filtering inductor L2, the positive pole of the first output filtering capacitor E4 and pin 8 of the operational amplifier U11, respectively; The other end of the filtering inductor L2, the positive pole of the second output filtering capacitor E5 and one end of the resistor R53 are connected to the DC voltage output positive terminal CV+; The sixth end of the secondary side winding of the isolation transformer T1, the negative pole of the first output filtering capacitor E4 and the negative pole of the second output filtering capacitor E5 are all connected to the DC voltage output negative terminal G1.

[0011] The constant current control circuit comprises the operational amplifier U11 and the second current sampling resistor R47; the second current sampling resistor R47 is connected in series between the DC voltage output negative terminal G1 and the system ground B-; Pin 1 of the operational amplifier U11 is connected to the cathode of the reverse flow diode D5, and the anode of the reverse flow diode D5 is connected to the anode of the reverse flow diode D6; Pin 8 of the operational amplifier U11 is connected to one end of the resistor R49, one end of the current limiting resistor R37 and one end of the filtering inductor L2, respectively; the other end of the current limiting resistor R37 is connected to the anode of the light emitting diode in the constant current feedback optical coupler U6; Pin 7 of the operational amplifier U11 is connected to the cathode of the reverse flow diode D6, and the anode of the reverse flow diode D6 is connected to the cathode of the light emitting diode in the constant current feedback optical coupler U6; The constant current feedback optical coupler U6 is connected in parallel with a resistor R42; The pin 6 of the operational amplifier U11 is connected with one end of the capacitor C9 and one end of the resistor R48 respectively; the other end of the resistor R48 is connected with the system ground B-; the other end of the capacitor C9 is connected with the DC voltage output negative terminal G1; The pin 5 of the operational amplifier U11 is connected with the emitter of the photoelectric triode in the feedback optical couplings U7, U8, U9 and U10 and the other end of the first reference resistor R51 respectively; The pin 2 of the operational amplifier U11 is connected with one end of the resistor R50 and the other end of the resistor R53 respectively, and the other end of the resistor R50 is connected with the DC voltage output negative terminal G1; The pin 3 of the operational amplifier U11 is connected with the other end of the resistor R49.

[0012] The technical scheme provided by the application has the beneficial effects that: Adaptive energy distribution mechanism: according to the CT energy power size, the energy output path is dynamically adjusted. When the CT energy is greater than the load demand, the power supply is preferentially supplied and the surplus energy is used to charge the battery; when the CT energy is insufficient, the battery power supply is automatically switched to ensure continuous operation of the equipment.

[0013] Multi-stage constant current control and optical coupling feedback: through the cooperation of the voltage dividing resistor, the voltage reference source and the optical coupling, the duty cycle of the PWM chip is adjusted to realize multi-stage adjustable output current and optimize the energy utilization efficiency.

[0014] Input overvoltage protection design: a transient suppression diode and a thyristor are combined to conduct and discharge when the CT energy is excessive, limit the input voltage of the power supply and protect the safety of the circuit. BRIEF DESCRIPTION OF DRAWINGS

[0015] The application will be further described below in conjunction with the drawings and embodiments, wherein: Figure 1 It is a circuit diagram in the embodiment of the application; Figure 2 It is a principle diagram in the embodiment of the application. DETAILED DESCRIPTION

[0016] In order to have a clearer understanding of the technical features, purposes and effects of the application, the specific embodiments of the application will be described in detail with reference to the drawings.

[0017] The embodiment of the application provides a CT energy power supply circuit with adaptive output power.

[0018] Please refer to Figure 1 , Figure 1 It is a step diagram of a CT energy power supply circuit with adaptive output power in the embodiment of the application, comprising: The circuit comprises a power input protection module, a rectification and filtering module, a DC-DC conversion module, a battery management module, a multi-stage adaptive feedback module and a direct current output module; the power input protection module, the rectification and filtering module, the DC-DC conversion module, the battery management module, the multi-stage adaptive feedback module and the direct current output module are electrically connected; The power input protection module is used for obtaining alternating current from the CT induction coil; The rectification and filtering module is used for rectifying the alternating current into pulsating direct current, and providing a stable direct current bus voltage for the subsequent conversion circuit after smoothing by a filtering capacitor; The DC-DC conversion module is used for efficiently converting the direct current bus voltage into an isolated direct current voltage suitable for the load; The battery management module is used for storing the excess energy into the battery when the CT energy is excessive, and seamlessly supplying power to the load by the battery when the CT energy is insufficient; The multi-stage adaptive feedback module is used for dynamically adjusting the output current reference through a multi-stage voltage comparison and optocoupler feedback network, so that the output power is adaptively matched with the CT power; The direct current output module is used for rectifying and filtering the converted voltage, and providing a stable and low-ripple direct current output.

[0019] The application adopts the above technical solution to design a CT power-taking power supply circuit with adaptive output power; the power-taking energy is adaptively and evenly distributed, and when the bus current is large during the power consumption peak, there is still excess energy to meet the power consumption of the monitoring and control equipment, and the excess energy is used to charge the battery; when the bus current is small during the power consumption valley, it is insufficient to meet the power consumption of the monitoring and control equipment, and the battery is used to supply power to the monitoring and control equipment, thereby ensuring the long-term stable operation of the monitoring and control equipment. The power supply reliability of the circuit is improved, the battery seamlessly supplies power during the CT power-taking valley, and the load equipment is ensured to work stably for a long time. The power-taking energy is efficiently utilized, the energy waste is reduced, and the circuit is adapted to the bus current fluctuation scene. The circuit structure is simple, the cost is controllable, and the circuit is easy to install and adapt, and is suitable for power supply of smart grid monitoring equipment.

[0020] As an embodiment, as shown in Figure 1 and Figure 2 When the current flows in the primary conductor, an induced current is generated on the power-taking winding, the induced current flows through the AC / DC power supply equivalent input resistor to form a voltage, and the power supply starts to work to supply power to the load connected to CV and G1; R47 and U11 are combined to adjust the duty cycle of the PWM chip (U5) output through the optocoupler to realize constant current output; when the CT output energy is less than the power loss Ploss of the power supply and the load power P, it is insufficient to maintain the regulated output, and the output voltage starts to decrease, and when the output voltage CV is less than the battery voltage VB (B+ and B- are connected to the battery), the battery discharges to maintain the load work; when the CT output energy When the power loss is greater than the power loss P + load power P, the CV voltage is maintained for regulated output. At this time, the constant current value is greater than or equal to the load current. The CT output energy is greater than the required energy, and the input voltage increases. After increasing to a certain level, the voltage at pin 1 of U1 is equal to 2.5V after being divided by R1-R4. Pins 2 and 3 of U1 are turned on, and U7 is also turned on. R38 + R43 are connected in parallel with resistor R52. The resistance of R52 decreases, the voltage division decreases, and the voltage division voltage on the voltage divider resistor R51 increases. As a result, the constant current value increases, and the output voltage begins to increase. When the output voltage CV value is higher than the battery voltage VB value, the excess energy begins to charge the load. When CT outputs energy When the input voltage is still greater than the power loss P of the power supply plus the load power P, the input voltage continues to rise. After rising to a certain level, the voltage at pin 1 of U2 is equal to 2.5V after being divided by R5, R6, R7, and R9. Pins 2 and 3 of U2 are turned on, and then U8 is also turned on. R39 and R44 are connected in parallel with resistor R52. The resistance value at R52 continues to decrease, the voltage division decreases, and the voltage division voltage on the voltage dividing resistor R51 increases. As a result, the constant current value increases, the current charging the battery increases, and more energy is charged to the battery. This process continues until all U7, U8, U9, and U10 are turned on, at which point the AC / DC output reaches its maximum power. If the CT outputs energy at this point... When the input voltage is still greater than the power loss P of the power supply plus the load power P, the input voltage continues to rise until it is higher than the transient suppression diode D1. D1 then conducts, and SCR1 conducts, allowing current to flow. This current circulates in the power extraction winding, thus ensuring that the AC / DC power supply input voltage does not exceed the voltage of D1, thereby achieving the function of input overvoltage protection. In the above process, if the CT output energy When the input voltage is initially less than the power loss P of the power supply plus the load power P, the input voltage drops, and the corresponding voltage reference source and optocoupler are cut off, thereby reducing the output power until it tends to balance.

[0021] The first input terminal L1 of the power input protection module is connected to one end of the varistor RV1, pin 2 of the first thyristor SCR1, one end of the first current limiting resistor R8, and one end of the resistor R10, respectively; the second input terminal N1 is connected to the other end of the varistor RV1, pin 1 of the first thyristor SCR1, one end of the capacitor C2, and one end of the capacitor C4, respectively; one end of the capacitor C4 is connected to the second input terminal of the common mode inductor L1; One end of transient suppression diode D1 is connected to the gate of the first thyristor SCR1, and the other end is connected to the other end of the first current limiting resistor R8 and the other end of capacitor C2; the other end of capacitor C4 is connected to the other end of resistor R10 and the first input terminal of common mode inductor L1 respectively. The first pin of the output terminal of the common mode inductor L1 is connected to the first AC input terminal of the rectifier bridge DB1 of the rectifier filter module, and the second pin of the output terminal of the common mode inductor L1 is connected to the second AC input terminal of the rectifier bridge DB1. The positive DC output terminal of the rectifier bridge DB1 is connected to the positive terminal of the first filter capacitor E1, and together they form the first DC node VIN+. The negative DC output terminal of the rectifier bridge DB1 and the negative terminal of the first filter capacitor E1 together form the first common ground GND1.

[0022] The DC-DC converter module includes a PWM control chip U5, a switching transistor Q1, and an isolation transformer T1; The first DC node VIN+ is connected to the first end of the primary winding of the isolation transformer T1, one end of the absorption capacitor C8, one end of the resistor R33, one end of the resistor R34, one end of the resistor R35 and one end of the resistor R19 respectively. The other end of the absorption capacitor C8, the other end of the resistor R33, the other end of the resistor R34, and the other end of the resistor R35 are connected to the cathode of the absorption diode D3. The third terminal of the primary winding of isolation transformer T1 is connected to the anode of absorption diode D3 and the drain of switching transistor Q1, respectively. The source of the switching transistor Q1 is connected to one end of the sampling resistor RS1, one end of the second current limiting resistor R25, and one end of the resistor R27, respectively. The gate of the switch Q1 is connected to the other end of resistor R27 and one end of resistor R21, respectively; The other end of resistor R21 is connected to pin 6 of PWM control chip U5; the other end of resistor R19 is connected to one end of resistor R20; the other end of resistor R20 is connected to pin 5 of PWM control chip U5.

[0023] The battery management module includes an anti-backflow diode D2 and an energy storage capacitor E2; The anode of the anti-backflow diode D2 is connected to the positive terminal CV+ of the DC voltage output, and its cathode is connected to pin 5 of the PWM control chip U5 and the positive terminal of the energy storage capacitor E2; the negative terminal of the energy storage capacitor E2 is grounded.

[0024] Pin 5 of the PWM control chip U5 is also connected to an auxiliary power supply circuit; The auxiliary power supply circuit includes an auxiliary winding rectifier diode D4 and an auxiliary power supply filter capacitor E3. The third terminal of the auxiliary winding of the isolation transformer T1 is connected to the anode of the auxiliary winding rectifier diode D4 through resistor R36; the cathode of the auxiliary winding rectifier diode D4 is connected to the positive terminal of the auxiliary power supply filter capacitor E3 and the anode of the anti-reverse current diode D2, respectively. The fifth terminal of the auxiliary winding of the isolation transformer T1 and the negative terminal of the auxiliary power supply filter capacitor E3 are grounded.

[0025] The multi-level adaptive feedback module includes an input voltage sampling chain, a multi-level voltage comparator chain, and an adjustable reference circuit. The input voltage sampling chain, the multi-stage voltage comparator chain, and the adjustable reference circuit are connected sequentially. The input voltage sampling chain is composed of multiple voltage divider resistors R1, R2, R3, R4, R5, R6, R7, R9, R11, R12, R13, R14, R15, R16, R17, and R18 connected in series between the first DC node VIN+ and the first common ground GND1, forming multiple voltage divider nodes. The multi-stage voltage comparator chain includes at least two parallel voltage reference source chips U1, U2, U3 and U4; The reference input terminal REF of each voltage reference source chip is connected to a voltage divider node of the input voltage sampling chain, and the cathodes of voltage reference source chips U1, U2, U3 and U4 are respectively connected to the anodes of the light-emitting diodes in feedback optocouplers U7, U8, U9 and U10. The cathode of the light-emitting diode in each feedback optocoupler U7, U8, U9 and U10 is grounded; The LEDs of feedback optocouplers U7, U8, U9 and U10 are connected in parallel with resistors R29, R30, R31 and R32, respectively; The anodes of the LEDs in the feedback optocouplers U7, U8, U9, and U10 are connected to one end of resistors R28, R26, R24, and R23, respectively; the other ends of resistors R28, R26, R24, and R23 are connected to the positive terminal CV+ of the DC voltage output. The adjustable reference circuit includes a first reference resistor R51 and a second reference resistor R52 connected in series. One end of the first reference resistor R51 is connected to the negative terminal G1 of the DC voltage output, and the other end of the first reference resistor R51 is connected to one end of the second reference resistor R52; the other end of the second reference resistor R52 is connected to pin 3 of the operational amplifier U11. The collectors of the phototransistors in the feedback optocouplers U7, U8, U9 and U10 are connected to the two ends of the second reference resistor R52 through an adjustment branch consisting of four sets of adjustment resistors R38 and R43, R39 and R44, R40 and R45, and R41 and R46 connected in series.

[0026] The DC output module includes a secondary-side rectifier and filter circuit and a constant current control circuit; The secondary-side rectifier and filter circuit is connected to the constant current control circuit. The secondary-side rectifier and filter circuit specifically includes: The tenth terminal of the secondary winding of the isolation transformer T1 is connected to the anode of the output rectifier diode D7; The cathode of the output rectifier diode D7 is connected to one end of the output filter inductor L2, the positive terminal of the first output filter capacitor E4, and pin 8 of the operational amplifier U11, respectively. The other end of the filter inductor L2, the positive terminal of the second output filter capacitor E5, and one end of the resistor R53 are connected to the positive terminal CV+ of the DC voltage output. The sixth terminal of the secondary winding of the isolation transformer T1, the negative terminal of the first output filter capacitor E4, and the negative terminal of the second output filter capacitor E5 are all connected to the negative terminal G1 of the DC voltage output.

[0027] The constant current control circuit includes an operational amplifier U11 and a second current sampling resistor R47; the second current sampling resistor R47 is connected in series between the negative terminal of the DC voltage output G1 and the system ground B-. Pin 1 of the operational amplifier U11 is connected to the cathode of the reverse diode D5, and the anode of the reverse diode D5 is connected to the anode of the reverse diode D6. Pin 8 of the operational amplifier U11 is connected to one end of resistor R49, one end of current-limiting resistor R37, and one end of filter inductor L2, respectively; the other end of current-limiting resistor R37 is connected to the anode of the light-emitting diode in constant current feedback optocoupler U6. Pin 7 of the operational amplifier U11 is connected to the cathode of the anti-reverse diode D6, and the anode of the anti-reverse diode D6 is connected to the cathode of the light-emitting diode in the constant current feedback optocoupler U6. A constant current feedback optocoupler U6 is connected in parallel with a resistor R42; Pin 6 of the operational amplifier U11 is connected to one end of capacitor C9 and one end of resistor R48; the other end of resistor R48 is connected to the system ground B-; the other end of capacitor C9 is connected to the negative terminal G1 of the DC voltage output. Pin 5 of the operational amplifier U11 is connected to the emitter of the phototransistor in the feedback optocouplers U7, U8, U9 and U10 and the other end of the first reference resistor R51, respectively. Pin 2 of the operational amplifier U11 is connected to one end of resistor R50 and the other end of resistor R53, respectively. The other end of resistor R50 is connected to the negative terminal G1 of the DC voltage output. The operational amplifier U11 has its pin 3 connected to the other end of resistor R49.

[0028] This application provides an embodiment as follows: the chip U1 uses the LL431 model; the chip U2 uses the LL431 model; the chip U3 uses the LL431 model; the chip U4 uses the LL431 model; the chip U5 uses the AP8267 model; the chip U6 uses the EL1019 model; the chip U7 uses the EL1019 model; the chip U8 uses the EL1019 model; the chip U9 uses the EL1019 model; the chip U10 uses the EL1019 model; and the chip U11 uses the AP4310 model.

[0029] The above are merely exemplary embodiments of this disclosure and should not be construed as limiting the scope of this disclosure. Any equivalent changes and modifications made in accordance with the teachings of this disclosure shall still fall within the scope of this disclosure.

[0030] This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not described in this disclosure. The specification and embodiments are to be considered exemplary only, and the scope and spirit of this disclosure are defined by the claims.

Claims

1. A CT power supply circuit with adaptive output power, characterized in that, The circuit includes: an energy input protection module, a rectification and filtering module, a DC-DC converter module, a battery management module, a multi-level adaptive feedback module, and a DC output module; the energy input protection module, the rectification and filtering module, the DC-DC converter module, the battery management module, the multi-level adaptive feedback module, and the DC output module are electrically connected to each other; The power input protection module is used to obtain AC power from the CT induction coil; The rectifier and filter module is used to rectify AC power into pulsating DC power, which is then smoothed by the filter capacitor to provide a stable DC bus voltage for the subsequent conversion circuit. DC-DC converter modules are used to efficiently convert DC bus voltage into isolated DC voltage suitable for the load; The battery management module is used to store excess energy in the battery when the CT has excess energy; and to seamlessly power the load from the battery when the CT has insufficient energy. The multi-level adaptive feedback module is used to dynamically adjust the output current reference through a multi-level voltage comparison and optocoupler feedback network, so that the output power adaptively matches the energy harvesting size of the CT. The DC output module is used to rectify and filter the converted voltage, providing a stable, low-ripple DC output.

2. The adaptive output power CT power supply circuit as described in claim 1, characterized in that, The first input terminal L1 of the power input protection module is connected to one end of the varistor RV1, pin 2 of the first thyristor SCR1, one end of the first current limiting resistor R8, and one end of the resistor R10, respectively; the second input terminal N1 is connected to the other end of the varistor RV1, pin 1 of the first thyristor SCR1, one end of the capacitor C2, and one end of the capacitor C4, respectively; one end of the capacitor C4 is connected to the second input terminal of the common mode inductor L1; One end of transient suppression diode D1 is connected to the gate of the first thyristor SCR1, and the other end is connected to the other end of the first current limiting resistor R8 and the other end of capacitor C2; the other end of capacitor C4 is connected to the other end of resistor R10 and the first input terminal of common mode inductor L1 respectively. The first pin of the output terminal of the common mode inductor L1 is connected to the first AC input terminal of the rectifier bridge DB1 of the rectifier filter module, and the second pin of the output terminal of the common mode inductor L1 is connected to the second AC input terminal of the rectifier bridge DB1. The positive DC output terminal of the rectifier bridge DB1 is connected to the positive terminal of the first filter capacitor E1, and together they form the first DC node VIN+. The negative DC output terminal of the rectifier bridge DB1 and the negative terminal of the first filter capacitor E1 together form the first common ground GND1.

3. The adaptive output power CT power supply circuit as described in claim 2, characterized in that, The DC-DC converter module includes a PWM control chip U5, a switching transistor Q1, and an isolation transformer T1; The first DC node VIN+ is connected to the first end of the primary winding of the isolation transformer T1, one end of the absorption capacitor C8, one end of the resistor R33, one end of the resistor R34, one end of the resistor R35 and one end of the resistor R19 respectively. The other end of the absorption capacitor C8, the other end of the resistor R33, the other end of the resistor R34, and the other end of the resistor R35 are connected to the cathode of the absorption diode D3. The third terminal of the primary winding of isolation transformer T1 is connected to the anode of absorption diode D3 and the drain of switching transistor Q1, respectively. The source of the switching transistor Q1 is connected to one end of the sampling resistor RS1, one end of the second current limiting resistor R25, and one end of the resistor R27, respectively. The gate of the switch Q1 is connected to the other end of resistor R27 and one end of resistor R21, respectively; The other end of resistor R21 is connected to pin 6 of PWM control chip U5; the other end of resistor R19 is connected to one end of resistor R20; the other end of resistor R20 is connected to pin 5 of PWM control chip U5.

4. The adaptive output power CT power supply circuit as described in claim 3, characterized in that, The battery management module includes an anti-backflow diode D2 and an energy storage capacitor E2; The anode of the anti-backflow diode D2 is connected to the positive terminal CV+ of the DC voltage output, and its cathode is connected to pin 5 of the PWM control chip U5 and the positive terminal of the energy storage capacitor E2; the negative terminal of the energy storage capacitor E2 is grounded.

5. The adaptive output power CT power supply circuit as described in claim 4, characterized in that, Pin 5 of the PWM control chip U5 is also connected to an auxiliary power supply circuit; The auxiliary power supply circuit includes an auxiliary winding rectifier diode D4 and an auxiliary power supply filter capacitor E3. The third terminal of the auxiliary winding of the isolation transformer T1 is connected to the anode of the auxiliary winding rectifier diode D4 through resistor R36; the cathode of the auxiliary winding rectifier diode D4 is connected to the positive terminal of the auxiliary power supply filter capacitor E3 and the anode of the anti-reverse current diode D2, respectively. The fifth terminal of the auxiliary winding of the isolation transformer T1 and the negative terminal of the auxiliary power supply filter capacitor E3 are grounded.

6. The adaptive output power CT power supply circuit as described in claim 5, characterized in that, The multi-level adaptive feedback module includes an input voltage sampling chain, a multi-level voltage comparator chain, and an adjustable reference circuit. The input voltage sampling chain, the multi-stage voltage comparator chain, and the adjustable reference circuit are connected sequentially. The input voltage sampling chain is composed of multiple voltage divider resistors R1, R2, R3, R4, R5, R6, R7, R9, R11, R12, R13, R14, R15, R16, R17, and R18 connected in series between the first DC node VIN+ and the first common ground GND1, forming multiple voltage divider nodes. The multi-stage voltage comparator chain includes at least two parallel voltage reference source chips U1, U2, U3 and U4; The reference input terminal REF of each voltage reference source chip is connected to a voltage divider node of the input voltage sampling chain, and the cathodes of voltage reference source chips U1, U2, U3 and U4 are respectively connected to the anodes of the light-emitting diodes in feedback optocouplers U7, U8, U9 and U10. The cathode of the light-emitting diode in each feedback optocoupler U7, U8, U9 and U10 is grounded; The LEDs of feedback optocouplers U7, U8, U9 and U10 are connected in parallel with resistors R29, R30, R31 and R32, respectively; The anodes of the LEDs in the feedback optocouplers U7, U8, U9, and U10 are connected to one end of resistors R28, R26, R24, and R23, respectively; the other ends of resistors R28, R26, R24, and R23 are connected to the positive terminal CV+ of the DC voltage output. The adjustable reference circuit includes a first reference resistor R51 and a second reference resistor R52 connected in series. One end of the first reference resistor R51 is connected to the negative terminal G1 of the DC voltage output, and the other end of the first reference resistor R51 is connected to one end of the second reference resistor R52; the other end of the second reference resistor R52 is connected to pin 3 of the operational amplifier U11. The collectors of the phototransistors in the feedback optocouplers U7, U8, U9 and U10 are connected to the two ends of the second reference resistor R52 through an adjustment branch consisting of four sets of adjustment resistors R38 and R43, R39 and R44, R40 and R45, and R41 and R46 connected in series.

7. The adaptive output power CT power supply circuit as described in claim 6, characterized in that, The DC output module includes a secondary-side rectifier and filter circuit and a constant current control circuit; The secondary-side rectifier and filter circuit is connected to the constant current control circuit. The secondary-side rectifier and filter circuit specifically includes: The tenth terminal of the secondary winding of the isolation transformer T1 is connected to the anode of the output rectifier diode D7; The cathode of the output rectifier diode D7 is connected to one end of the output filter inductor L2, the positive terminal of the first output filter capacitor E4, and pin 8 of the operational amplifier U11, respectively. The other end of the filter inductor L2, the positive terminal of the second output filter capacitor E5, and one end of the resistor R53 are connected to the positive terminal CV+ of the DC voltage output. The sixth terminal of the secondary winding of the isolation transformer T1, the negative terminal of the first output filter capacitor E4, and the negative terminal of the second output filter capacitor E5 are all connected to the negative terminal G1 of the DC voltage output.

8. The adaptive output power CT power supply circuit as described in claim 7, characterized in that, The constant current control circuit includes an operational amplifier U11 and a second current sampling resistor R47; the second current sampling resistor R47 is connected in series between the negative terminal of the DC voltage output G1 and the system ground B-. Pin 1 of the operational amplifier U11 is connected to the cathode of the reverse diode D5, and the anode of the reverse diode D5 is connected to the anode of the reverse diode D6. Pin 8 of the operational amplifier U11 is connected to one end of resistor R49, one end of current-limiting resistor R37, and one end of filter inductor L2, respectively; the other end of current-limiting resistor R37 is connected to the anode of the light-emitting diode in constant current feedback optocoupler U6. Pin 7 of the operational amplifier U11 is connected to the cathode of the anti-reverse diode D6, and the anode of the anti-reverse diode D6 is connected to the cathode of the light-emitting diode in the constant current feedback optocoupler U6. A constant current feedback optocoupler U6 is connected in parallel with a resistor R42; Pin 6 of the operational amplifier U11 is connected to one end of capacitor C9 and one end of resistor R48; the other end of resistor R48 is connected to the system ground B-; the other end of capacitor C9 is connected to the negative terminal G1 of the DC voltage output. Pin 5 of the operational amplifier U11 is connected to the emitter of the phototransistor in the feedback optocouplers U7, U8, U9 and U10 and the other end of the first reference resistor R51, respectively. Pin 2 of the operational amplifier U11 is connected to one end of resistor R50 and the other end of resistor R53, respectively. The other end of resistor R50 is connected to the negative terminal G1 of the DC voltage output. The operational amplifier U11 has its pin 3 connected to the other end of resistor R49.

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