Current transformer in-situ detection circuit and system

Abstract

The invention relates to the technical field of electronic circuits, and discloses a current transformer in-situ detection circuit and system, through a three-stage circuit architecture, under the condition that a power line of an external CT is not required to be electrified, a processing chip can actively send out a control signal, and the control signal passes through a switch driving module and a switch execution module to conduct a state detection module in sequence, so that the current transformer in-situ detection circuit is obtained. Therefore, the voltage of the CT can be sampled by the state detection module, and rapid and high-reliability in-place detection is realized by utilizing the difference that the voltage is inevitably 0V or non-0V when the CT is in-place / not in-place. Compared with a traditional detection mode depending on power line current, the circuit is not affected by the system operation condition, detection can be completed under the standby condition, the safety coefficient is high, operation is convenient and fast, software detection logic is fused, CT in-situ inspection can be operated on line, and great convenience is provided for daily operation and maintenance of the system.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic circuits, and in particular to a current transformer in-situ detection circuit and system. Background Art

[0002] In recent years, the residential energy storage sector has experienced an exceptionally booming market. This burgeoning market phenomenon, like a powerful engine, has driven the entire energy storage inverter technology industry into a new phase of rapid evolution. With numerous companies entering this market, competition has intensified. To secure a niche in this fierce competition, companies are continuously focusing on cost control, resulting in extreme cost reductions.

[0003] Regarding the current technical application of residential energy storage inverters, to fully meet the diverse and unique needs of user scenarios, with the exception of some special cases, the vast majority of residential energy storage inverters utilize an external CT (current transformer) sampling solution. This solution offers numerous advantages, such as ease of operation and quick deployment, and strongly supports the rapid promotion and application of the product. However, in actual implementation, external CT sampling is typically achieved through RJ45 terminals and cable locks. This connection method has certain drawbacks. Due to various factors such as the installation environment and operating procedures, it is prone to problems such as poor or missing connections of the external CT. Once such problems occur, they can seriously impact the normal operation of the energy storage inverter and may even lead to safety accidents. Therefore, to ensure the stable and reliable operation of the energy storage inverter, accurate detection of the correct CT position is essential.

[0004] Traditional CT in-situ detection solutions have significant limitations. They require current flowing through the power lines sampled by external CTs before they can make judgments based on relevant parameters. However, in actual operation, due to the complexity and uncertainty of power systems, this detection method is highly likely to cause system malfunctions, posing potential risks to the safe and stable operation of the entire energy storage system.

[0005] Therefore, in order to effectively solve the problems existing in the existing technology, improve the performance and reliability of household energy storage inverters, and reduce system operation risks, it is imperative to improve the existing technology.

[0006] The above information is presented as background information only to assist with an understanding of the present disclosure and is not a determination or admission that any of the above may be applicable as prior art with respect to the present disclosure. Summary of the Invention

[0007] The present invention provides a current transformer on-site detection circuit and system to solve the problems existing in the prior art.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] In a first aspect, the present invention provides a current transformer in-position detection circuit, comprising a switch driving module, a switch execution module and a state detection module; wherein,

[0010] The switch driving module is connected to the processing chip and is used to receive a control signal from the processing chip to generate a driving current;

[0011] The switch execution module is connected to the switch driving module and the state detection module respectively, and is used to execute the action of closing the switch after receiving the driving current to turn on the state detection module;

[0012] The status detection module is connected to the current transformer CT and the processing chip respectively, and is used to sample the voltage of the current transformer CT after conduction, and feed the sampled voltage back to the processing chip; if the sampled voltage is 0V, it is determined that the current transformer CT is in place; if the sampled voltage is not 0V, it is determined that the current transformer CT is not in place.

[0013] Furthermore, in the current transformer in-position detection circuit, the switch driving module includes a Test_control 1 port, a Test_control 2 port, a first voltage stabilizing diode ZD1, a second voltage stabilizing diode ZD2, a first transistor Q1, a second transistor Q2, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4;

[0014] The Test_control 1 port and the Test_control 2 port are respectively connected to the processing chip;

[0015] The cathode of the first voltage stabilizing diode ZD1 is connected to the Test_control 1 port, and the anode of the first voltage stabilizing diode ZD1 is connected to the base of the first transistor Q1;

[0016] The emitter of the first transistor Q1 is grounded;

[0017] The first diode D1 and the second diode D2 are connected in parallel, the positive electrode of the first diode D1 is connected to the collector of the first transistor Q1, and the negative electrode of the first diode D1 is connected to the first auxiliary power supply;

[0018] The cathode of the second voltage stabilizing diode ZD2 is connected to the Test_control 2 port, and the anode of the second voltage stabilizing diode ZD2 is connected to the base of the second transistor Q2;

[0019] The emitter of the second transistor Q2 is grounded;

[0020] After the third diode D3 and the fourth diode D4 are connected in parallel, the anode is connected to the collector of the second transistor Q2, and the cathode is connected to the first auxiliary power supply.

[0021] Furthermore, in the current transformer in-position detection circuit, the switch driving module further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4;

[0022] The first resistor R1 and the first capacitor C1 are connected in parallel, one end of which is connected to the base of the first transistor Q1, and the other end of which is connected to the emitter of the first transistor Q1;

[0023] The second resistor R2 is connected in series between the anode of the first voltage stabilizing diode ZD1 and the base of the first transistor Q1;

[0024] One end of the second capacitor C2 is connected to the first auxiliary power supply, and the other end is grounded;

[0025] The third resistor R3 and the third capacitor C3 are connected in parallel, one end of which is connected to the base of the second transistor Q2, and the other end of which is connected to the emitter of the second transistor Q2;

[0026] The fourth resistor R4 is connected in series between the anode of the second voltage stabilizing diode ZD2 and the base of the second transistor Q2;

[0027] One end of the fourth capacitor C4 is connected to the first auxiliary power supply, and the other end is grounded.

[0028] Furthermore, in the current transformer in-position detection circuit, the switch execution module includes a first relay RLY1, a second relay RLY2, a fifth resistor R5, a sixth resistor R6 and a fifth diode D5;

[0029] The coil of the first relay RLY1 is connected in parallel to the first diode D1 and the second diode D2, the movable contact of the first relay RLY1 is connected in series with the fifth resistor R5 and then connected to the second auxiliary power supply, and the static contact of the first relay RLY1 is connected to the first end of the secondary side of the current transformer CT;

[0030] The coil of the second relay RLY2 is connected in parallel to the third diode D3 and the fourth diode D4, the moving contact of the second relay RLY2 is connected to the anode of the fifth diode D5, and the static contact of the first relay RLY1 is connected to the second end of the secondary side of the current transformer CT;

[0031] The cathode of the fifth diode D5 is connected to the first end of the secondary side of the current transformer CT;

[0032] The sixth resistor R6 is connected in parallel to both ends of the secondary side of the current transformer CT;

[0033] A second terminal of the secondary side of the current transformer CT is grounded.

[0034] Further, in the current transformer in-position detection circuit, the status detection module includes a CT_TEST_AD+ port and a CT_TEST_AD- port;

[0035] The CT_TEST_AD+ port is connected to the first end of the secondary side of the current transformer CT and the processing chip respectively;

[0036] The CT_TEST_AD- port is connected to the second end of the secondary side of the current transformer CT and the processing chip.

[0037] Furthermore, in the current transformer in-position detection circuit, the first auxiliary power supply provides a voltage of +12V, and the second auxiliary power supply provides a voltage of +3.3V.

[0038] Furthermore, in the current transformer in-position detection circuit, the first voltage stabilizing diode ZD1 and the second voltage stabilizing diode ZD2 are 3.3V voltage stabilizing diodes.

[0039] In a second aspect, the present invention provides a current transformer in-place detection system, comprising a processing chip, a current transformer CT, and a current transformer in-place detection circuit as provided in the first aspect above;

[0040] The processing chip is used to send a control signal to the switch driving module, so that the switch driving module generates a driving current;

[0041] The switch execution module is used to execute the action of closing the switch after receiving the driving current to turn on the state detection module;

[0042] The state detection module is used to sample the voltage of the current transformer CT and feed the sampled voltage back to the processing chip;

[0043] The processing chip is also used to make the following judgments:

[0044] If the sampled voltage is 0V, it is determined that the current transformer CT is in place; if the sampled voltage is not 0V, it is determined that the current transformer CT is not in place.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] The present invention provides a current transformer presence detection circuit and system. Through a three-stage circuit architecture, a processing chip actively sends a control signal, which, even when the power line is energized without an external CT, sequentially connects to the state detection module via a switch driver module and a switch execution module. This allows the state detection module to sample the CT voltage and, by leveraging the difference between the voltage being 0V and non-0V when the CT is present and absent, achieves fast and highly reliable presence detection. Compared to traditional detection methods that rely on power line current, this circuit is unaffected by system operating conditions and can complete detection in standby mode. It offers a high safety factor and convenient operation. The integration of software detection logic allows CT presence checks to be performed online, greatly facilitating routine system operations and maintenance.

[0047] The present invention has other features and advantages that will be apparent from or will be described in detail in the accompanying drawings and the following detailed description incorporated herein, which together serve to explain certain principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 This is a functional module diagram of a current transformer in-position detection circuit provided in the first embodiment of the present invention;

[0050] Figure 2 This is a schematic diagram of the circuit principle of a current transformer in-position detection circuit provided in Example 1 of the present invention.

[0051] Reference numerals:

[0052] Switch driving module 1, switch execution module 2, state detection module 3, current transformer CT 4, processing chip 5. DETAILED DESCRIPTION

[0053] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0054] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0055] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0056] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0057] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0058] Without further limitations, in this application, the words "include", "comprise", "have" or other similar expressions used in the sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those defined elements, but also other elements not explicitly listed, or elements inherent to such process, method or product.

[0059] In this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means two or more (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups" and "multiple times," unless otherwise specifically limited.

[0060] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0061] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0062] Example 1

[0063] Please refer to Figure 1 The embodiment of the present invention provides a current transformer in-position detection circuit. The circuit as a whole adopts a carefully designed three-level circuit architecture, specifically including three core components: a switch driving module 1, a switch execution module 2, and a status detection module 3.

[0064] The switch driver module 1 establishes a stable electrical connection with the processing chip 5. Its core function is to receive precise control signals from the processing chip 5. Upon receiving these control signals, the switch driver module 1 generates a corresponding drive current. This drive current serves as a key trigger signal for subsequent circuit actions, laying the foundation for initiating the entire detection process.

[0065] The switch execution module 2 plays a key role in executing key actions in the circuit. It establishes reliable connections with the switch driver module 1 and the status detection module 3. Upon receiving the drive current output by the switch driver module 1, the switch execution module 2 immediately closes the switch. This action enables the status detection module 3, which was previously in an off state, to conduct, thus creating the necessary circuit path for subsequent status detection of the current transformer CT 4.

[0066] The status detection module 3 has a dual connection: on one hand, it is closely connected to the current transformer CT 4, and on the other hand, it maintains communication with the processing chip 5. After the switch execution module 2 turns on the status detection module 3, the status detection module 3 quickly starts sampling the voltage of the current transformer CT 4. It uses high-precision sampling technology to accurately obtain the real-time voltage value of the current transformer CT 4 and feeds this sampled voltage back to the processing chip 5 in a stable and accurate manner. After receiving the sampled voltage, the processing chip 5 performs an in-depth analysis based on the preset judgment logic: if the sampled voltage value is 0V, it can be clearly determined that the current transformer CT 4 is in the in-position state; conversely, if the sampled voltage value is not 0V, it is determined that the current transformer CT 4 is not in the in-position state.

[0067] The current transformer in-place detection circuit provided by the embodiments of the present invention exhibits significant technical advantages due to its unique and advanced three-stage circuit architecture. During the detection process, the processing chip 5 can actively send a control signal without relying on the traditional condition that the power line of the external CT is energized. This control signal is precisely transmitted and executed by the switch drive module 1 and the switch execution module 2, ultimately successfully turning on the status detection module 3. Subsequently, the status detection module 3 accurately samples the voltage of the current transformer CT 4 and cleverly utilizes the characteristic that the voltage of the current transformer CT 4 will inevitably show a significant difference of 0V or non-0V when the current transformer CT 4 is in place and when it is not in place, thereby achieving rapid and highly reliable detection of the in-place status of the current transformer CT 4.

[0068] Compared to traditional detection methods that rely on power line current, this circuit offers numerous advantages. It is unaffected by the complexities of system operating conditions and can easily complete detection tasks even when the system is in standby mode, significantly improving the safety and stability of detection and significantly increasing the safety factor. Furthermore, its operation is simple and quick, requiring no cumbersome steps or additional equipment. Furthermore, this circuit cleverly incorporates advanced software detection logic, enabling convenient online CT in-situ inspections. This feature greatly facilitates the system's daily operations and maintenance, effectively reducing costs and improving efficiency, and is of great practical significance for ensuring the stable operation of the entire power system.

[0069] Please refer to Figure 2 In one implementation of this embodiment, the switch driving module 1 includes a Test_control 1 port, a Test_control 2 port, a first voltage stabilizing diode ZD1, a second voltage stabilizing diode ZD2, a first transistor Q1, a second transistor Q2, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4;

[0070] In terms of port connection, the Test_control 1 port and the Test_control 2 port are respectively electrically connected to the processing chip 5 to receive the control signal sent by the processing chip 5.

[0071] The cathode of the first voltage stabilizing diode ZD1 is connected to the Test_control 1 port, and the anode thereof is connected to the base of the first transistor Q1 via the second resistor R2. The emitter of the first transistor Q1 is grounded.

[0072] After the first diode D1 and the second diode D2 are connected in parallel, the anode is connected to the collector of the first transistor Q1 , and the cathode is connected to the first auxiliary power supply providing a +12V voltage.

[0073] Similarly, the cathode of the second voltage stabilizing diode ZD2 is connected to the Test_control 2 port, the anode is connected to the base of the second transistor Q2 via the fourth resistor R4, and the emitter of the second transistor Q2 is grounded.

[0074] After the third diode D3 and the fourth diode D4 are connected in parallel, the anode is connected to the collector of the second transistor Q2 , and the cathode is also connected to the first auxiliary power supply.

[0075] Please refer again Figure 2 In one implementation of this embodiment, the switch driving module 1 further includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4;

[0076] In the connection between the resistor and the capacitor, after the first resistor R1 and the first capacitor C1 are connected in parallel, one end is connected to the base of the first transistor Q1, and the other end is connected to the emitter of the first transistor Q1, which plays the role of stabilizing the base voltage and filtering.

[0077] One end of the second capacitor C2 is connected to the first auxiliary power supply, and the other end is grounded, and is used for filtering the first auxiliary power supply.

[0078] After the third resistor R3 and the third capacitor C3 are connected in parallel, one end is connected to the base of the second transistor Q2, and the other end is connected to the emitter of the second transistor Q2, which also plays the role of stabilizing the base voltage and filtering.

[0079] One end of the fourth capacitor C4 is connected to the first auxiliary power supply, and the other end is grounded, and is also used to filter the first auxiliary power supply.

[0080] Please refer again Figure 2 In one implementation of this embodiment, the switch execution module 2 includes a first relay RLY1, a second relay RLY2, a fifth resistor R5, a sixth resistor R6 and a fifth diode D5;

[0081] The coil of the first relay RLY1 is connected in parallel to the first diode D1 and the second diode D2. Its movable contact is connected in series with the fifth resistor R5 and then connected to the second auxiliary power supply providing +3.3V voltage. Its static contact is connected to the first terminal of the secondary side of the current transformer CT4.

[0082] The coil of the second relay RLY2 is connected in parallel to the third diode D3 and the fourth diode D4, the movable contact thereof is connected to the anode of the fifth diode D5, and the static contact thereof is connected to the second end of the secondary side of the current transformer CT4.

[0083] The cathode of the fifth diode D5 is connected to the first end of the secondary side of the current transformer CT4, and plays a role in protecting the circuit and preventing reverse current.

[0084] The sixth resistor R6 is connected in parallel to both ends of the secondary side of the current transformer CT4.

[0085] A second terminal of the secondary side of the current transformer CT 4 is grounded, providing a stable electrical circuit for the current transformer CT 4 .

[0086] Please refer again Figure 2 In one implementation of this embodiment, the status detection module 3 includes a CT_TEST_AD+ port and a CT_TEST_AD- port;

[0087] The CT_TEST_AD+ port is connected to the first end of the secondary side of the current transformer CT 4 and the processing chip 5 respectively, and is used to collect the voltage signal of the secondary side of the current transformer CT 4 and transmit it to the processing chip 5 .

[0088] The CT_TEST_AD- port is connected to the second end of the secondary side of the current transformer CT 4 and the processing chip 5, and is used to cooperate with the CT_TEST_AD+ port to form a voltage detection loop, so that the processing chip 5 can determine whether the current transformer CT 4 is in place based on the voltage difference between the two ends.

[0089] Please refer again Figure 2 In one implementation of this embodiment, the first auxiliary power supply provides a voltage of +12V, and the second auxiliary power supply provides a voltage of +3.3V.

[0090] It should be noted that the first auxiliary power supply provides a stable +12V voltage to provide working power for the relevant components in the switch driver module 1; the second auxiliary power supply provides a +3.3V voltage to provide a suitable working voltage for some components in the switch execution module 2, ensuring that the entire circuit can operate stably under different voltage requirements.

[0091] Please refer again Figure 2 In one implementation of this embodiment, the first voltage stabilizing diode ZD1 and the second voltage stabilizing diode ZD2 are both 3.3V voltage stabilizing diodes, which have the following functions: (1) input voltage (5V) to the Test_control 1 port and the Test_control 2 port to ensure that the first transistor Q1 and the second transistor Q2 can operate normally; (2) prevent the circuit from malfunctioning when the Test_control 1 port and the Test_control 2 port are left floating; thereby improving the stability and reliability of the entire switch driving module 1.

[0092] This embodiment of the present invention focuses on detecting the presence of current transformer CT 4 by processing chip 5. Through the coordinated operation of switch driver module 1, switch execution module 2, and status detection module 3, combined with specific control signal logic, accurate determination of the presence of current transformer CT 4 is achieved. The following describes this in detail, following the implementation steps.

[0093] 1. Control signal sending and relay closing

[0094] Processing chip 5 (using a DSP as an example), serving as the control core of the entire system, sends high-level control signals to ports Test_control 1 and Test_control 2. The voltage of these high-level signals exceeds the 3.3V regulation voltage of the first and second Zener diodes ZD1 and ZD2. This design ensures that the control signals can effectively drive subsequent circuit components.

[0095] Because the control signal voltage is higher than the regulated voltage of the Zener diodes, the first and second Zener diodes ZD1 and ZD2 enter reverse breakdown, stabilizing the voltage across them at 3.3V. This provides sufficient forward bias voltage at the bases of the first and second transistors Q1 and Q2, turning them on. This conduction provides a path for current to flow, energizing the subsequent relay coils.

[0096] After transistors Q1 and Q2 are turned on, current flows through the coils of relays RLY1 and RLY2, respectively. The current generates a magnetic field in the relay coils, which attracts the movable contacts (i.e., the armatures) and activates them, causing both relays RLY1 and RLY2 to switch from an open state to a closed state. This state transition provides the necessary circuit connection conditions for subsequent current transformer in-place detection.

[0097] 2. Current transformer in-situ detection

[0098] When current transformer CT 4 is in place, its secondary side forms a complete electrical loop. At this point, the voltage difference between the CT_TEST_AD+ and CT_TEST_AD- terminals is theoretically 0V. This is because the impedance of the current transformer's secondary side is ideally negligible, and the circuit connections are good, resulting in no additional voltage drop.

[0099] If current transformer CT 4 is not in place, the circuit connection changes. At this point, the voltage between the CT_TEST_AD+ and CT_TEST_AD- ports is no longer 0V. The specific voltage value can be calculated using the circuit voltage divider principle: 3.3*(R5 / (R1+R5)). Here, 3.3V is the voltage provided by the second auxiliary power supply, R5 is a resistor connected in series in the circuit, and R1 can be understood as another equivalent resistance in the circuit (in a practical circuit, it may be composed of the impedances of multiple components). By detecting the voltage values ​​of these two ports, the processing chip 5 can determine whether current transformer CT 4 is in place.

[0100] 3. Control signal reset and relay disconnection

[0101] After completing the current transformer in-place detection, the processing chip 5 controls the Test_control 1 port and the Test_control 2 port to output a low-level signal. At this time, the voltage across the first Zener diode ZD1 and the second Zener diode ZD2 is 0V, which cannot provide a forward bias voltage for the base of the first transistor Q1 and the second transistor Q2.

[0102] Since the bases do not have sufficient forward bias voltage, the first transistor Q1 and the second transistor Q2 are both non-conductive and in the off state. After the transistors are turned off, the current flow path is cut off, so that no current flows through the coils of the first relay RLY1 and the second relay RLY2.

[0103] When the relay coil loses current, the magnetic field disappears, and the armature returns to its initial position under the action of the reset spring. Both the first relay RLY1 and the second relay RLY2 switch from a closed state to an open state. This process completes the reset of the entire test process and prepares for the next test.

[0104] The embodiment of the present invention realizes efficient and accurate detection of the in-position state of the current transformer through precise control signal logic and ingenious circuit design, and has high reliability and practicality.

[0105] Although this application frequently uses terms such as processing chip and switch execution module, the use of other terms is not excluded. These terms are used solely to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

[0106] Example 2

[0107] A current transformer in-place detection system provided in a second embodiment of the present invention includes a processing chip, a current transformer CT, and a current transformer in-place detection circuit as provided in the first embodiment above;

[0108] The processing chip is used to send a control signal to the switch driving module, so that the switch driving module generates a driving current;

[0109] The switch execution module is used to execute the action of closing the switch after receiving the driving current to turn on the state detection module;

[0110] The state detection module is used to sample the voltage of the current transformer CT and feed the sampled voltage back to the processing chip;

[0111] The processing chip is also used to make the following judgments:

[0112] If the sampled voltage is 0V, it is determined that the current transformer CT is in place; if the sampled voltage is not 0V, it is determined that the current transformer CT is not in place.

[0113] It's important to note that the processing chip, as the core control unit of the entire system, is responsible for sending control signals and performing logical judgments. It can be a chip with powerful processing capabilities and a rich set of interfaces, such as a DSP (digital signal processor), which can precisely control the system's operation according to pre-set programs and logic.

[0114] The current transformer (CT) is the detection target of this system. Its main function is to proportionally convert the high current on the primary side into a smaller current on the secondary side for measurement and protection. In this system, the current transformer's status is the key information that needs to be detected.

[0115] The CT in-position detection circuit is a circuit provided in the first embodiment of the present invention, which includes a switch driving module, a switch execution module, and a state detection module. Under the control of the processing chip, the circuit detects the in-position state of the current transformer CT.

[0116] The current transformer presence detection system provided in Example 2 of the present invention achieves efficient and accurate detection of the presence of current transformers (CTs) through the collaborative operation of various modules. This system has the advantages of simple structure, high reliability, and low cost, and can be widely used in fields such as power generation and industrial control.

[0117] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concepts of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A current transformer in-position detection circuit, characterized in that: It comprises a switch driving module (1), a switch execution module (2) and a state detection module (3); wherein, The switch driving module (1) is connected to the processing chip (5) and is used to receive a control signal from the processing chip (5) to generate a driving current; The switch execution module (2) is connected to the switch driving module (1) and the state detection module (3) respectively, and is used to execute the action of closing the switch after receiving the driving current, so as to turn on the state detection module (3); The state detection module (3) is connected to the current transformer CT (4) and the processing chip (5) respectively, and is used for sampling the voltage of the current transformer CT (4) after being turned on, and feeding the sampled voltage back to the processing chip (5); if the sampled voltage is 0V, it is determined that the current transformer CT (4) is in place; if the sampled voltage is not 0V, it is determined that the current transformer CT (4) is not in place.

2. The current transformer in-position detection circuit according to claim 1, characterized in that: The switch driving module (1) comprises a Test_control 1 port, a Test_control 2 port, a first voltage stabilizing diode ZD1, a second voltage stabilizing diode ZD2, a first transistor Q1, a second transistor Q2, a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4; The Test_control 1 port and the Test_control 2 port are respectively connected to the processing chip (5); The cathode of the first voltage stabilizing diode ZD1 is connected to the Test_control 1 port, and the anode of the first voltage stabilizing diode ZD1 is connected to the base of the first transistor Q1; The emitter of the first transistor Q1 is grounded; The first diode D1 and the second diode D2 are connected in parallel, the positive electrode of the first diode D1 is connected to the collector of the first transistor Q1, and the negative electrode of the first diode D1 is connected to the first auxiliary power supply; The cathode of the second voltage stabilizing diode ZD2 is connected to the Test_control 2 port, and the anode of the second voltage stabilizing diode ZD2 is connected to the base of the second transistor Q2; The emitter of the second transistor Q2 is grounded; After the third diode D3 and the fourth diode D4 are connected in parallel, the anode is connected to the collector of the second transistor Q2, and the cathode is connected to the first auxiliary power supply.

3. The current transformer in-position detection circuit according to claim 2, characterized in that: The switch driving module (1) further comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3 and a fourth capacitor C4; The first resistor R1 and the first capacitor C1 are connected in parallel, one end of which is connected to the base of the first transistor Q1, and the other end of which is connected to the emitter of the first transistor Q1; The second resistor R2 is connected in series between the anode of the first voltage stabilizing diode ZD1 and the base of the first transistor Q1; One end of the second capacitor C2 is connected to the first auxiliary power supply, and the other end is grounded; The third resistor R3 and the third capacitor C3 are connected in parallel, one end of which is connected to the base of the second transistor Q2, and the other end of which is connected to the emitter of the second transistor Q2; The fourth resistor R4 is connected in series between the anode of the second voltage stabilizing diode ZD2 and the base of the second transistor Q2; One end of the fourth capacitor C4 is connected to the first auxiliary power supply, and the other end is grounded.

4. The current transformer in-position detection circuit according to claim 2, characterized in that: The switch execution module (2) comprises a first relay RLY1, a second relay RLY2, a fifth resistor R5, a sixth resistor R6 and a fifth diode D5; The coil of the first relay RLY1 is connected in parallel to the first diode D1 and the second diode D2, the movable contact of the first relay RLY1 is connected in series with the fifth resistor R5 and then connected to the second auxiliary power supply, and the static contact of the first relay RLY1 is connected to the first end of the secondary side of the current transformer CT (4); The coil of the second relay RLY2 is connected in parallel to the third diode D3 and the fourth diode D4, the moving contact of the second relay RLY2 is connected to the positive electrode of the fifth diode D5, and the static contact of the first relay RLY1 is connected to the second end of the secondary side of the current transformer CT (4); The cathode of the fifth diode D5 is connected to the first end of the secondary side of the current transformer CT (4); The sixth resistor R6 is connected in parallel to both ends of the secondary side of the current transformer CT (4); The second end of the secondary side of the current transformer CT (4) is grounded.

5. The current transformer in-position detection circuit according to claim 4, characterized in that: The status detection module (3) includes a CT_TEST_AD+ port and a CT_TEST_AD- port; The CT_TEST_AD+ port is connected to the first end of the secondary side of the current transformer CT (4) and the processing chip (5) respectively; The CT_TEST_AD-port is connected to the second end of the secondary side of the current transformer CT (4) and the processing chip (5).

6. The current transformer in-position detection circuit according to claim 5, characterized in that: The first auxiliary power supply provides a voltage of +12V, and the second auxiliary power supply provides a voltage of +3.3V.

7. The current transformer in-position detection circuit according to claim 6, characterized in that: The first Zener diode ZD1 and the second Zener diode ZD2 are 3.3V Zener diodes.

8. A current transformer in-situ detection system, characterized in that: comprising a processing chip, a current transformer CT, and a current transformer in-position detection circuit according to any one of claims 1 to 7; The processing chip is used to send a control signal to the switch driving module, so that the switch driving module generates a driving current; The switch execution module is used to execute the action of closing the switch after receiving the driving current to turn on the state detection module; The state detection module is used to sample the voltage of the current transformer CT and feed the sampled voltage back to the processing chip; The processing chip is also used to make the following judgments: If the sampled voltage is 0V, it is determined that the current transformer CT is in place; if the sampled voltage is not 0V, it is determined that the current transformer CT is not in place.

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