WO2024002033A1

WO2024002033A1 - Signal injection circuit and injection method

Info

Publication number: WO2024002033A1
Application number: PCT/CN2023/102532
Authority: WO
Inventors: 胡信煌; 胡应龙; 刘彬; 朱可
Original assignee: 上海正泰智能科技有限公司
Priority date: 2022-06-27
Filing date: 2023-06-26
Publication date: 2024-01-04
Also published as: CN115065051A

Abstract

The present application discloses a signal injection circuit and injection method. The signal injection circuit comprises a constant current generation module and a feedback module. The constant current generation module is used to switch a working state according to a frequency driving signal, and when the constant current generation module is in an on state, output a constant current feature signal to the feedback module. The frequency driving signal is a signal used for physical topology identification of a low-voltage power transformer region. The feedback module is used to adjust a feedback signal according to the constant current feature signal. The feedback signal is used to reflect an occurrence status of the constant current feature signal. According to the present application, the constant current feature signal has no influence on the power supply quality of a power grid, which improves the reliability of power system operations, the success rate of physical topology identification of the low-voltage power transformer region can be increased by means of the feedback signal, and the rate of physical topology identification is further increased, thereby ensuring the reliability of physical topology identification.

Description

Signal injection circuit and injection method

Technical field

The present application relates to the field of electronic circuit technology, and specifically to a signal injection circuit and an injection method.

Background technique

The low-voltage power station area is the area where a certain transformer provides low-voltage power supply. The purpose of dividing the station area is to facilitate power management, so as to make the management in terms of personnel division of labor, equipment maintenance, power calculation, line loss statistics, etc. more scientific and standardized. The physical topology, as the core of low-voltage power station informatization, is directly related to the timeliness and accuracy of low-voltage power station information processing.

At present, the physical topology of low-voltage power stations can be recorded through the method of step-by-step power outage. However, this method has a low degree of intelligence and can only be recorded incidentally during major maintenance processes. It cannot achieve real-time recording and is inconsistent with the era of intelligent industry; Another method is the short-circuit characteristic current identification method, which is to install a characteristic signal generation and identification device at a designated location, and obtain relevant information by identifying the current changing characteristics of equipment in low-voltage power stations. However, this method introduces the short-circuit characteristic current, and the short circuit The characteristic current will introduce more high-order harmonics, causing serious distortion of the voltage waveform, which will affect the quality of power supply.

Contents of the invention

This application provides a signal injection circuit and injection method, aiming to solve the problem that the physical topology of the existing low-voltage power station area affects the power supply quality.

In the first aspect, this application provides a signal injection circuit, including a constant current generation module and a feedback module;

The constant current generation module is used to convert the working state according to the frequency drive signal. When the constant current generation module is in the on state, it outputs the constant current characteristic signal to the feedback module; the frequency drive signal is a signal used to identify the physical topology of the low-voltage power station area. ;

The feedback module is used to adjust the feedback signal according to the constant current characteristic signal; the feedback signal is used to reflect the occurrence status of the constant current characteristic signal.

In a possible implementation of this application, the signal injection circuit also includes a power module, and the constant current generating module is connected to a load;

The power module is used to obtain the DC voltage signal and voltage stabilization signal based on the AC voltage signal of the low-voltage power station area, and output the DC voltage signal and voltage stabilization signal to the constant current generation module to power the load through the constant current generation module;

The constant current generation module is used to make the load work in the constant current region when it is in the conduction state, and to obtain the constant current characteristic signal that indicates that the load operates in the constant current region.

In a possible implementation of this application, the power module includes a rectification unit and a voltage stabilizing unit;

The rectification unit is used to rectify the AC voltage signal and obtain the DC voltage signal and output it to the voltage stabilizing unit and the constant current generation module respectively;

The voltage stabilizing unit is used to stabilize the DC voltage signal and output the stabilized voltage signal to the constant current generating module.

In a possible implementation of the present application, the constant current generation module includes a first switch unit, a second switch unit and a first isolation switch unit;

The first isolating switch unit is used to convert the working state according to the frequency drive signal. When the first isolating switch unit When in the conductive state, output the drive control signal to the first switch unit;

The second switch unit is used to obtain a constant voltage signal according to the voltage stabilization signal, and is turned on when the first switch unit is turned on, and outputs the constant voltage signal to the first switch unit;

The first switch unit is configured to be turned on according to the drive control signal to output a constant voltage signal to the load, and to output a constant current characteristic signal indicating that the load is operating in the constant current region to the feedback module.

In a possible implementation of the present application, the first switch unit includes a first switch transistor, the second switch unit includes a second switch transistor, and the first isolation switch unit includes a first optocoupler;

The anode of the light emitter of the first optocoupler receives the frequency drive signal, one end of the photoreceiver of the first optocoupler is connected to the reference ground, and the other end outputs the drive control signal to the gate of the first switch tube;

The gate of the second switch tube receives the constant voltage signal, and the source of the second switch tube outputs a constant voltage signal to the source of the first switch tube;

The drain of the first switch tube outputs a constant voltage signal to the load and a constant current characteristic signal to the feedback module.

In a possible implementation of this application, the feedback module includes a second isolation switch unit;

When the second isolation switch unit is in the off state, a feedback signal based on the first level is obtained;

When the second isolation switch unit switches from the off state to the on state in response to the constant current characteristic signal, a feedback signal based on the second level is obtained.

In a possible implementation of the present application, the feedback module further includes a conversion unit, which is connected to the constant current generating module and the second isolation switch unit respectively. The conversion unit is used to convert the constant current characteristic signal into a feedback control signal and output it to Second isolating switch unit.

In a possible implementation of the present application, the conversion unit includes a twelfth resistor, the second isolation switch unit includes a second optocoupler, one end of the twelfth resistor receives the constant current characteristic signal, and the other end outputs a feedback control signal to the first The anode of the light emitter of the second photocoupler, and the photoreceiver of the second photocoupler output a feedback signal.

In a possible implementation of this application, the signal injection circuit also includes a control unit, which is connected to the constant current generation module and the feedback module respectively;

The control unit is configured to inject a frequency drive signal into the constant current generation module of the target node in response to the injection signal from the main station of the low-voltage power station area, and determine the generation status of the constant current characteristic signal based on the feedback signal output by the feedback module.

In a second aspect, this application also provides a signal injection method, which is applied to the signal injection circuit of the first aspect. The signal injection method includes:

The constant current generation module of the signal injection circuit switches working state according to the frequency drive signal. When the constant current generation module is in the on state, it outputs the constant current characteristic signal to the feedback module of the signal injection circuit; the frequency drive signal is used in low-voltage power stations. Signals for physical topology identification;

The feedback module adjusts the feedback signal according to the constant current characteristic signal; the feedback signal is used to reflect the occurrence status of the constant current characteristic signal.

From the above content, it can be concluded that this application has the following beneficial effects:

In this application, the constant current generation module converts the working state according to the frequency drive signal used for physical topology identification of low-voltage power stations. When the constant current generation module is in the on state, it outputs the constant current characteristic signal to the feedback module, and the feedback module is then based on The constant current characteristic signal adjusts the feedback signal to reflect the occurrence status of the constant current characteristic signal through the feedback signal, thereby According to the occurrence state of the constant current characteristic signal, it can be known whether the frequency driving signal is injected. Compared with the occurrence method of the physical topology of the existing low-voltage power station area, which will affect the power supply quality, the constant current characteristic signal of this application has an impact on the power supply of the power grid. There is no impact on quality, which improves the reliability of power system operation, and the feedback signal can improve the success rate of physical topology identification in low-voltage power station areas, thereby increasing the rate of physical topology identification and ensuring the reliability of physical topology identification.

Description of drawings

In order to explain the technical solutions in this application more clearly, the drawings needed to be used in the description of this application will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of this application and are not useful in this field. For technical personnel, other drawings can also be obtained based on these drawings without exerting creative work.

Figure 1 is a schematic structural diagram of a signal injection circuit provided in an embodiment of the present application;

Figure 2 is another structural schematic diagram of the signal injection circuit provided in the embodiment of the present application;

Figure 3 is another structural schematic diagram of the signal injection circuit provided in the embodiment of the present application;

Figure 4 is a schematic circuit diagram of the power module provided in the embodiment of the present application;

Figure 5 is a schematic circuit diagram of the signal injection circuit provided in the embodiment of the present application;

Figure 6 is a schematic flow chart of the signal injection method provided in the embodiment of the present application.

Detailed ways

The technical solutions in this application will be clearly and completely described below with reference to the accompanying drawings in this application. Obviously, the described embodiments are only some of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of this application.

In the description of this application, it needs to be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", " The directions or positional relationships indicated by "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. are based on the directions shown in the accompanying drawings or positional relationship is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms “first” and “second” are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of indicated technical features. Therefore, the features defined as “first” and “second” may explicitly or implicitly include one or more features. In the description of this application, "plurality" means two or more than two, unless otherwise explicitly and specifically limited.

It should be noted that “connection” in the embodiments of this application can be understood as electrical connection, and the connection between two electrical components can be a direct or indirect connection between two electrical components. For example, A and B may be connected directly, or A and B may be connected indirectly through one or more other electrical components.

In this application, the word "exemplary" is used to mean "serving as an example, illustration, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. The following description is presented to enable any person skilled in the art to make and use the present application. In the following description, details are set forth for the purpose of explanation. It will be understood that one of ordinary skill in the art will recognize that the present application may be practiced without these specific details. In other instances, well-known structures and processes have not been described in detail to avoid obscuring the description of the application with unnecessary detail. Thus, this application is not intended to be limited to the embodiments shown but is to be accorded the widest scope consistent with the principles and features disclosed herein.

The present application provides a signal injection circuit and an injection method. The signal injection circuit and the injection method of the present application are described in detail below.

First, this application provides a signal injection circuit that can adjust the feedback signal in response to the frequency driving signal after injecting the frequency driving signal, thereby judging the working status of the signal injection circuit based on the feedback signal, and then judging the current target node. Whether the frequency drive signal has been injected.

It can be understood that for a low-voltage power station area, it can have multiple power supply nodes, and each power supply node can be connected through a certain topology. At the same time, a master station can be configured in the low-voltage power station area to communicate with each power supply node. Communication, the master station can send control instructions such as signal injection instructions to each power supply node, or obtain the working conditions of each power supply node and feedback on control instructions to quickly identify and process abnormal information such as line loss, power theft, and fault alarms. The effect is to ensure the safety of electricity consumption and improve the reliability of power system operation.

Please refer to Figure 1. Figure 1 is a schematic structural diagram of the signal injection circuit provided in the embodiment of the present application. As shown in Figure 1, the signal injection circuit in the embodiment of the present application includes a constant current generation module 100 and a feedback module 200, wherein, The constant current generating module 100 can be used to convert the working state according to the frequency drive signal. When the constant current generating module 100 is in the conductive state, it outputs the constant current characteristic signal to the feedback module 200. The frequency drive signal is used in low-voltage power station area physics. Topology identification signal; the feedback module 200 can be used to adjust the feedback signal according to the constant current characteristic signal, and the feedback signal can be used to reflect the occurrence state of the constant current characteristic signal.

It can be understood that for a low-voltage power station area with a tree topology, since the current flows from top to bottom, when the master station sends an injection signal to a certain target node, the power station located above the target node The node can listen to the injected signal, but the nodes located below the target node cannot listen to the injected signal. Therefore, the master station can determine the relationship between the target node and each node based on the feedback from each node in the topology and the target node. According to the topological relationship between the two nodes, an injection signal is sent to each node in the topology, and the physical topology of the low-voltage power station area can be determined based on the feedback from each node.

When the target node receives the injection signal sent by the master station, it can inject the frequency driving signal into its corresponding signal injection circuit. In the embodiment of the present application, the frequency driving signal can be a pulse width modulation (Pulse Width Modulation, PWM) signal. The parameters such as amplitude, frequency, duty cycle or pulse width of the PWM signal can be selected according to the actual application scenario.

When the constant current generating module 100 receives the PWM signal, it can convert its own working state according to the PWM signal. When the constant current generating module 100 is turned on in response to the PWM signal, the constant current generating module can output the constant current characteristic signal to Feedback module 200.

In the embodiment of the present application, the constant current generating module 100 can be configured with two working states: on and off. The constant current generating module 100 can switch between the two working states according to the input PWM signal. When the constant current generating module When the constant current generating module 100 is turned on in response to the PWM signal, it can output a constant current characteristic signal; and when the constant current generating module 100 is turned off in response to the PWM signal, the constant current generating module 100 has no signal output.

It can be understood that in order to avoid affecting the power supply quality, the constant current characteristic signal may be a small current signal, and since the constant current characteristic signal is generated by the constant current generating module 100 in response to the PWM signal, the generation of the constant current characteristic signal The time and duration of occurrence are related to the PWM signal.

For example, if the duty cycle of the PWM signal is 70%, that is to say, within one cycle of the PWM signal, the time when the PWM signal is high level accounts for 70% of the entire cycle. If the PWM signal is high level, the constant current The generating module 100 is turned on. Since when the constant current generating module 100 is turned on, a constant current characteristic signal is output, the generation time of the constant current characteristic signal is also the entire cycle. 70% of the period, and the occurrence time is consistent with the time when the PWM signal is high level.

In the embodiment of the present application, after receiving the constant current characteristic signal output by the constant current generation module 100, the feedback module 200 can adjust the output of the feedback signal according to the constant current characteristic signal, so that the feedback signal can reflect the occurrence status of the constant current characteristic signal. , further, it can reflect whether the target node has been injected with a frequency driving signal, that is, a PWM signal.

It can be understood that the feedback signal can be a digital signal, and the feedback module 200 adjusts the output of the feedback signal according to the constant current characteristic signal. For example, if the feedback signal output by the feedback module 200 is configured in a normally high state in advance, it can also That is to say, when no constant current characteristic signal is input to the feedback module 200, the feedback signal is always high level, and when the feedback module 200 receives the constant current characteristic signal, the output feedback signal can be adjusted in response to the constant current characteristic signal. From high level to low level, the level state of the feedback signal can reflect the occurrence state of the constant current characteristic signal.

In the same way, the feedback signal output by the feedback module 200 can also be configured in advance to a normally low state. That is to say, when no constant current characteristic signal is input to the feedback module 200, the feedback signal is always low level, and when the feedback module 200 After receiving the constant current characteristic signal, the output feedback signal can be converted from low level to high level in response to the constant current characteristic signal. Therefore, the level state of the feedback signal can also reflect the occurrence state of the constant current characteristic signal. .

It is worth noting that the feedback module 200 adjusts the output of the feedback signal according to the constant current characteristic signal, and can also adopt other adjustment methods. Any adjustment method that can reflect the occurrence status of the constant current characteristic signal through changes in the feedback signal can be applied to this application. , which can be determined based on actual application scenarios and is not specifically limited here.

In the embodiment of the present application, the constant current generation module 100 switches the working state according to the frequency drive signal used for physical topology identification of the low-voltage power station area. When the constant current generation module 100 is in the conductive state, the constant current characteristic signal is output to the feedback module 200 , the feedback module 200 then adjusts the feedback signal based on the constant current characteristic signal to reflect the occurrence state of the constant current characteristic signal through the feedback signal, so that it can be known whether the frequency driving signal is injected according to the occurrence state of the constant current characteristic signal. Compared with the existing The physical topology of the low-voltage power station area will have an impact on the power supply quality. The constant current characteristic signal of this application has no impact on the power supply quality of the power grid. There is no need to record power outages step by step, which improves the reliability of the power system operation, and through The feedback signal can improve the success rate of physical topology identification in low-voltage power station areas, thereby increasing the rate of physical topology identification and ensuring the reliability of physical topology identification.

Please refer to Figure 2. Figure 2 is another schematic structural diagram of a signal injection circuit provided in an embodiment of the present application. In some embodiments of the present application, the signal injection circuit also includes a control unit 300. The control unit 300 can be configured with a constant current controller. The generation module 100 and the feedback module 200 are connected.

The control unit 300 may be configured to inject a frequency drive signal into the constant current generation module 100 of the target node in response to an injection signal from the main station of the low-voltage power station area, and determine the generation status of the constant current characteristic signal according to the feedback signal output by the feedback module 200 .

In the embodiment of the present application, the control unit 300 may be a microcontroller unit (MCU), a single-chip computer, or other integrated circuit chip that integrates a central processor, a memory, and a variety of input and output interfaces.

It can be understood that the control unit 300 can be configured with a communication component to implement communication with the master station. When the master station sends an injection signal to the target node, the control unit 300 can respond to the injection signal according to the preset injection time and Relevant parameters of the frequency driving signal, such as duty cycle, frequency, amplitude, etc., are injected into the constant current generating module 100.

Moreover, the control unit 300 can also receive the feedback signal output by the feedback module 200, and determine whether the constant current generating module 100 generates the constant current characteristic signal according to the change of the feedback signal. In other words, it can also determine whether the constant current characteristic signal is generated by the change of the feedback signal. A frequency driving signal is injected into the constant current generating module 100 .

In addition, the control unit 300 can also feed back the signal injection situation of the target node to the master station, so that the master station can determine the injection situation based on the feedback information. At the same time, the master station can also receive the listening feedback information of other nodes in the topology structure, thereby passing Feedback information and listening feedback information construct the topological relationship between the target node and other nodes.

Please continue to refer to Figure 2. In some embodiments of the present application, the signal injection circuit may also include a power module 400, and the constant current generation module 100 may be connected to a load 500. The power module 400 can be used to obtain a DC voltage signal and a voltage stabilization signal according to the AC voltage signal of the low-voltage power station, and output the DC voltage signal and voltage stabilization signal to the constant current generation module 100 to provide the load 500 with the constant current generation module 100 Power supply; the constant current generation module 100 can also be used to make the load 500 work in the constant current region when in the conduction state, and obtain a constant current characteristic signal indicating that the load operates in the constant current region.

Since the low-voltage power station area is a low-voltage power supply area of a certain transformer, the low-voltage power station area can output an AC voltage signal to the power module 400. The power module 400 in the embodiment of the present application can convert the AC voltage signal of the low-voltage power station area. The DC voltage signal and the voltage stabilized signal are then output to the constant current generating module 100 to supply power to the load 500 through the constant current generating module 100 .

It can be understood that the AC voltage signal in the low-voltage power station area is a sinusoidal signal that changes with time. If the load 500 is to work in the constant current area, a constant voltage or a constant current needs to be provided to the load 500. Therefore, the power module 400 can The AC voltage signal is rectified to obtain a DC voltage signal. At the same time, since the DC voltage signal is a pulsating signal, the constant current generating module 100 needs to output a constant voltage or a constant voltage to the load 500 without being affected by the pulsating DC voltage signal. Constant current, so that the load 500 works in the constant current zone.

Please refer to Figure 3. Figure 3 is another structural schematic diagram of a signal injection circuit provided in an embodiment of the present application. In some embodiments of the present application, the power module 400 may include a rectifier unit 401 and a voltage stabilizing unit 402; the rectifier unit 401 may It is used to rectify the AC voltage signal, and the DC voltage signal is output to the voltage stabilizing unit 402 and the constant current generation module 100 respectively; the voltage stabilizing unit 402 can be used to stabilize the DC voltage signal, and the voltage stabilizing signal is output to the constant current generator. Module 100 occurs.

In this embodiment of the present application, the rectifier unit 401 can be any existing rectifier device or rectifier circuit, such as a half-wave rectifier circuit, a full-bridge rectifier circuit, etc.

It can be understood that the DC voltage signal output by the rectifier unit 401 is a pulsating signal. Therefore, in the embodiment of the present application, the DC voltage signal can also be filtered through a filter device, thereby improving the waveform of the output voltage and reducing the pulsation of the DC voltage signal. The amplitude becomes smaller.

In the embodiment of the present application, in order to further stabilize the output waveform of the DC voltage signal, the DC voltage signal is also stabilized through the voltage stabilizing unit 402, so that the stabilized voltage signal is output to the constant current generating module 100. It can be understood that the stabilized voltage signal is The voltage stabilizing unit 402 can use any existing voltage stabilizing device or voltage stabilizing circuit. For example, the voltage stabilizing unit 402 in this embodiment can be a DC voltage stabilizing circuit, a switching voltage stabilizing circuit or a series voltage stabilizing circuit. any type of voltage circuit.

Please refer to Figure 4. Figure 4 is a schematic circuit diagram of a power module provided in an embodiment of the present application. In a specific implementation, the rectification unit 401 includes a first diode D1, a second diode D2, The three diodes D3 and the fourth diode D4 form a rectifier bridge. The voltage stabilizing unit 402 includes the voltage stabilizing diode Z1. The specific circuit connection structure is:

The live wire L of the low-voltage power station is connected to the anode of the first diode D1 and the cathode of the fourth diode D4 through the fuse F1 and the first current-limiting resistor. Here, the first current-limiting resistor is a third parallel-connected resistor. Resistor R3 and sixth resistor R6; the neutral line N of the low-voltage power station area is connected to the anode of the second diode D2 and the cathode of the sixth diode D6 through the second current limiting resistor. Here, the second current limiting resistor The eighth resistor R8 and the ninth resistor R9 are connected in parallel, and a varistor RV1 is also connected between the live wire L and the neutral wire N;

The cathode of the first diode D1 and the cathode of the second diode D2 are respectively connected to the first end of the fourth resistor R4 and the first end of the first filter capacitor C1. The second end and fourth end of the first filter capacitor C1 The anode of the diode D4 and the anode of the sixth diode D6 are respectively connected to the reference ground GND;

The second end of the fourth resistor R4 is connected in series with a seventh resistor R7, a forward-conducting third diode D3, an eleventh resistor R11 and a second capacitor C2. The cathode of the Zener diode Z1 is connected to the third diode. Between D3 and the eleventh resistor R11, the anode of the Zener diode Z1 is connected to the reference ground GND;

The first end of the fourth resistor R4 is also connected to the constant current generation module 100 for outputting a DC voltage signal. The cathode of the voltage stabilizing diode Z1 is also connected to the constant current generation module 100 for outputting a voltage stabilizing signal.

The working principle of the power module 400 is:

When the AC voltage signal of the low-voltage power station is in the positive half cycle, the first diode D1, the third diode D3 and the sixth diode D6 are forward-conducting, and the second diode D2 and the fourth diode are conductive in the forward direction. D4 is reverse cut-off. When the AC voltage signal of the low-voltage power station is in the negative half cycle, the second diode D2, the third diode D3 and the fourth diode D4 are forward-conducting, and the first diode D1 and The sixth diode D6 is reverse cut-off;

After the single-phase AC voltage signal between the live wire L and the neutral wire N is rectified by the rectifier bridge, a pulsating DC voltage signal is obtained, and then the DC voltage signal is filtered through the charging and discharging of the first filter capacitor C1, so that the DC voltage signal After the pulsation amplitude becomes smaller, the DC voltage signal is output to the constant current generating module 100 through the first interface V1;

At the same time, after the DC voltage signal is stepped down by the fourth resistor R4 and the seventh resistor R7, the voltage stabilizing diode Z1 outputs the voltage stabilizing signal to the constant current generating module 100 through the voltage stabilizing output interface Vz. The amplitude of the voltage stabilizing signal is is the stable voltage value of Zener diode Z1.

It can be understood that the varistor RV1 can play a role in lightning protection and overvoltage protection. As for the first filter capacitor C1, the larger its capacity, the smoother the waveform of the filtered DC voltage signal. The selection of the device can be determined according to the actual situation, and there is no specific limit here.

Please continue to refer to Figure 3. In some embodiments of the present application, the constant current generation module 100 may include a first switch unit 101, a second switch unit 102 and a first isolation switch unit 103; wherein the first isolation switch unit 103 may be When switching the working state according to the frequency drive signal, when the first isolation switch unit 103 is in the conductive state, the drive control signal is output to the first switch unit 101; the second switch unit 102 can be used to obtain a constant voltage signal according to the voltage stabilization signal, And it is turned on when the first switch unit 101 is turned on, and a constant voltage signal is output to the first switch unit 101; the first switch unit 101 can be used to be turned on according to the drive control signal to output a constant voltage signal to the load 500, And output a constant current characteristic signal indicating that the load 500 is operating in the constant current region to the feedback module 200 .

In the embodiment of the present application, since the frequency driving signal is a PWM signal, the first isolation switch unit 103 can respond to different levels of the PWM signal and switch working states. For example, when the PWM signal is high level, the first isolation switch unit 103 103 may be in a conductive state. On the contrary, when the PWM signal is low level, the first isolation switch unit 103 is in an off state; or, the first isolation switch unit 103 may also be in a conductive state when the PWM signal is low level. , when the PWM signal is high level, it is in the off state. The corresponding relationship between the first isolation switch unit 103 and the PWM signal can be determined according to the actual application scenario, and is not limited here.

When the first isolation switch unit 103 is turned on in response to the PWM signal, the first isolation switch unit 103 outputs a drive control signal to the first switch unit 101 , and the first switch unit 101 may be configured to be turned on in response to the drive control signal. , thus the second switch unit 102 is also turned on, and the constant voltage signal is output to the load 500 through the turned-on first switch unit 101, so that the load 500 operates in the constant current region, obtains a constant current, and forms a constant voltage drop.

In this embodiment of the present application, the first switching unit 101 and the second switching unit 102 may be transistors, metal-oxide semiconductor field-effect transistors (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), insulated gate bipolar transistors ( Insulated Gate Bipolar Transistor (IGBT) and other controllable switching devices, the first isolation switch unit 103 can be any existing photoelectric coupler, the first isolation switch unit 103 can isolate the AC signal of the low-voltage power station area , enhance the anti-interference ability of constant current characteristic signals.

As shown in Figure 5, Figure 5 is a schematic circuit diagram of the signal injection circuit provided in the embodiment of the present application. In a specific implementation, the first switch unit 101 includes a first switch transistor Q1, and a second switch unit 102 Including the second switch Q2, the first isolation switch unit 103 includes the first optocoupler U1; wherein, the anode of the emitter of the first optocoupler U1 receives the frequency driving signal, that is, the PWM signal, and one end of the photoreceiver of the first optocoupler U1 Connect the reference ground GND, and the other end outputs the drive control signal PWMC to the gate of the first switch Q1; the gate of the second switch Q2 receives the regulated signal, and the source of the second switch Q2 outputs a constant voltage signal to the first The source of the switch Q1 and the drain of the first switch Q1 output a constant voltage signal to the load 500 and a constant current characteristic signal to the feedback module 200 .

As shown in Figure 5, the load 500 in the embodiment of the present application is a first resistor R1 and a second resistor R2 connected in parallel. The first switch tube Q1 is a PMOS tube, and the second switch tube Q2 is an NMOS tube. The specific structure of the circuit is:

The drain of the second switching tube Q2, that is, pin 2, is connected to the first interface V1 to receive the DC voltage signal output by the rectification unit 401. The gate of the second switching tube Q2, that is, pin 1, is connected to the voltage stabilizing output interface Vz and receives the voltage stabilizing unit 402. For the output voltage stabilizing signal, the source electrode of the second switch tube Q2, which is pin 3, is connected to the source electrode of the first switch tube Q1, which is pin 2, and the fifth resistor R5 is connected to the gate electrode of the first switch tube Q1, which is pin 1. The first The drain of the switch Q1, namely pin 3, is connected to the feedback module 200, the first resistor R1 and the second resistor R2 respectively;

The gate of the first switch Q1 is connected to one end of the photoreceptor of the first optocoupler U1, which is pin 4. The other end of the photoreceptor, which is pin 3, is connected to the reference ground GND. The anode of the light emitter of the first optocoupler U1 is pin 1. To receive the PWM signal, the cathode of the light emitter, that is, pin 2, is connected to the digital reference ground DGND through the tenth resistor R10.

According to Figure 5, it can be known that the source voltage of the second switch Q2 is Vs=Vz-Vgs(th), where Vz is the stable voltage value of the Zener diode Z1, and Vgs(th) is the turn-on of the second switch Q2. The voltage threshold value, therefore, the required source voltage can be obtained by selecting the Zener diode Z1 with different stable voltage values and the second switching tube Q2 with different turn-on voltage threshold values, and the source voltage is output to The voltage amplitude of the constant voltage signal of the first switching tube Q1, that is to say, by selecting the zener diode Z1 and the second switching tube Q2, an ideal voltage for supplying power to the first resistor R1 and the second resistor R2 can be obtained. constant voltage.

The working principle of this circuit is:

When the PWM signal is low-level logic "0", the emitter of the first optocoupler U1 does not emit light, and then the photoreceiver of the first optocoupler U1 is disconnected, that is, the pin 3 and pin 4 are turned off. At this time, The voltage difference between the gate and the source of the first switch Q1 is 0, and the first switch Q1 is turned off. At the same time, the voltage difference between the gate and the source of the second switch Q2 is less than its opening voltage. limit value, the second switch Q2 is also turned off, so the constant current generating module 100 does not generate a constant current characteristic signal, and the load 500, that is, the first resistor R1 and the second resistor R2 are not connected to the circuit, and no current is generated.

When the PWM signal is a high-level logic "1", the emitter of the first optocoupler U1 emits light in the forward direction, and then the photoreceiver of the first optocoupler U1 turns on. Because pin 4 of the first optocoupler U1 is connected to the reference ground GND, then the drive control signal PWMC output by pin 3 of the first optocoupler U1 is low-level logic "0", the gate of the first switch Q1 is quickly pulled down to the reference ground GND, and the first switch Q1 is turned on. At this time, the voltage difference between the gate and the source of the second switch Q2 is greater than its turn-on voltage threshold, then the second switch Q2 is also turned on, and the source voltage Vs of the second switch Q2 is a constant voltage. Load the first resistor R1 through the first switch Q1 and both ends of the second resistor R2, thereby generating a constant load current. At the same time, when the first switch Q1 is turned on, the small current at its drain forms a constant current characteristic signal and is output to the feedback module 200.

In the embodiment of the present application, since the generated constant current characteristic signal will also cause a certain power consumption on the load 500, the first resistor R1 and the second resistor R2 are connected in parallel to reduce the resistance value and share the power. It can be understood that in In some other application scenarios, more resistors can be connected in parallel to form a load, which is not specifically limited here.

Please continue to refer to Figure 3. In some embodiments of the present application, the feedback module 200 may include a second isolation switch unit 201; when the second isolation switch unit 201 is in the off state, a feedback signal based on the first level is obtained; when When the second isolation switch unit 201 switches from the off state to the on state in response to the constant current characteristic signal, a feedback signal based on the second level is obtained.

In the embodiment of the present application, the second isolation switch unit 201 can be any existing photoelectric coupler. The second isolation switch unit 201 can also isolate AC signals in the low-voltage power station area. The second isolation switch unit 201 outputs The feedback signal can be configured in a normally high state, that is, when no constant current characteristic signal is input to the second isolation switch unit 201, the feedback signal is always high level, and when the second isolation switch unit 201 receives a constant current After generating the characteristic signal, the output feedback signal can be converted from high level to low level in response to the constant current characteristic signal, so that the level state of the feedback signal can reflect the occurrence state of the constant current characteristic signal.

In the same way, the feedback signal output by the second isolation switch unit 201 can also be configured in a normally low state in advance. That is to say, when no constant current characteristic signal is input to the second isolation switch unit 201, the feedback signal is always low level. , and when the second isolation switch unit 201 receives the constant current characteristic signal, it can convert the output feedback signal from low level to high level in response to the constant current characteristic signal, whereby the level state of the feedback signal is also It can reflect the occurrence status of constant current characteristic signal.

As shown in Figure 3, in some embodiments of the present application, the feedback module 200 may also include a conversion unit 202. The conversion unit 202 may be connected to the constant current generation module 100 and the second isolation switch unit 201 respectively. The conversion unit 202 may be The constant current characteristic signal is converted into a feedback control signal and output to the second isolation switch unit 201 .

Please continue to refer to Figure 5. In a specific implementation, the conversion unit 202 may include a twelfth resistor R12, the second isolation switch unit 201 may include a second optocoupler U2, and one end of the twelfth resistor R12 receives the first The drain of the switch Q1 is the constant current characteristic signal output by pin 3, and the other end outputs the feedback control signal FKC to the anode of the light emitter of the second optocoupler U2, which is pin 1. The cathode of the light emitter is connected to the reference ground GND. One end of the photoreceiver of optocoupler U2, namely pin 2, is connected to the digital reference ground DGND, and the other end, namely pin 1, outputs the feedback signal FK.

In the embodiment of this application, pin 4 of the second optocoupler U2 is configured in a normally high state, continuously outputting a high-level logic "1" feedback signal FK, and when the drain of the first switch Q1 outputs a constant current characteristic signal When , the constant current characteristic signal is converted into a feedback control signal FKC through the twelfth resistor R12 and output to the anode of the light emitter of the second optocoupler U2. Since the cathode of the light emitter of the second optocoupler U2 is connected to the reference ground GND, therefore, At this time, the emitter of the second optocoupler U2 is forward-conducting and emits light, and pins 3 and 4 of the photoreceiver of the second optocoupler U2 are connected. Since pin 3 of the photoreceptor of the second photocoupler U2 is connected to the digital reference ground DGND, , pin 4 of the photoreceiver of the second optocoupler U2 outputs a low-level logic "0" feedback signal FK; and when the drain of the first switch tube Q1 does not output a constant current characteristic signal, the second optocoupler U2 is turned off. , pin 4 of the second optocoupler U2 outputs a high-level logic "1" feedback signal FK.

The feedback signal FK can be output to the control unit 300 such as a microcontroller, so that the control unit 300 can use the feedback signal FK to determine whether the load 500 is operating in the constant current zone, and whether the circuit generates a constant current characteristic signal, and then determines whether the circuit responds to the main The injection signal of the station injects the frequency driving signal to ensure the reliability of circuit operation.

In another specific implementation, pin 3 of the photoreceptor of the second optocoupler U2 can also be connected to a power supply level such as +5V voltage. Pull high, in this application scenario, pin 4 of the second optocoupler U2 can be configured in a normally low state, continuously outputting a low-level logic "0" feedback signal FK, and when the drain output of the first switch Q1 is constant When the current characteristic signal is flowing, the constant current characteristic signal also drives the second optocoupler U2 to turn on. At this time, because pin 3 of the photoreceiver of the second optocoupler U2 is pulled high, therefore, pin 4 of the photoreceiver of the second optocoupler U2 pin outputs a high-level logic "1" feedback signal FK; when the drain of the first switch Q1 does not output a constant current characteristic signal, the second optocoupler U2 is turned off, and pin 4 of the second optocoupler U2 outputs a low Level logic "0" feedback signal FK.

On the basis of the above embodiments, the present application also provides a signal injection method, as shown in Figure 6. Figure 6 is a schematic flow chart of the signal injection method provided in the embodiment of the present application. This signal injection method can be applied to the signal injection circuit in any of the above embodiments. The signal injection method can include the following steps:

Step S601: The constant current generating module of the signal injection circuit switches working state according to the frequency drive signal. When the constant current generating module is in the on state, the constant current characteristic signal is output to the feedback module of the signal injection circuit; the frequency drive signal is used for low voltage Signals for physical topology identification of power station areas;

Step S602: The feedback module adjusts the feedback signal according to the constant current characteristic signal; the feedback signal is used to reflect the occurrence status of the constant current characteristic signal.

In the embodiment of the present application, the constant current generation module converts the working state according to the frequency drive signal used for physical topology identification of the low-voltage power station area. When the constant current generation module is in the conductive state, it outputs the constant current characteristic signal to the feedback module. The feedback module The feedback signal is then adjusted based on the constant current characteristic signal to reflect the occurrence state of the constant current characteristic signal through the feedback signal. Therefore, it can be known whether the frequency drive signal is injected according to the occurrence state of the constant current characteristic signal. Compared with the existing low-voltage power station The way in which the physical topology of the area occurs will have an impact on the power supply quality. The constant current characteristic signal of this application has no impact on the power supply quality of the power grid. At the same time, the frequency drive signal can be configured according to the actual situation, which enhances the resistance of the constant current characteristic signal. Interference capability improves the success rate of topology identification.

For the specific implementation of the signal injection method, please refer to the description of the signal injection circuit in any embodiment of the present application, as shown in Figures 1 to 5 of this application. The beneficial effects that can be achieved are detailed in the previous description and will not be repeated here.

In the above embodiments, each embodiment is described with its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the above detailed descriptions of other embodiments and will not be described again here.

During specific implementation, each of the above units or structures can be implemented as an independent entity, or can be combined in any way to be implemented as the same or several entities. For the specific implementation of each of the above units or structures, please refer to the previous embodiments and will not be discussed here. Again.

The above is a detailed introduction to a signal injection circuit and injection method provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The above description is only used to help understand the circuit of the present application and its implementation. Core idea; at the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of this application. In summary, the content of this description should not be understood as a limitation of this application.

Claims

A signal injection circuit, characterized by including a constant current generation module and a feedback module;

The constant current generating module is used to convert the working state according to the frequency drive signal. When the constant current generating module is in the conductive state, it outputs the constant current characteristic signal to the feedback module; the frequency drive signal is used for low voltage Signals for physical topology identification of power station areas;

The feedback module is used to adjust the feedback signal according to the constant current characteristic signal; the feedback signal is used to reflect the occurrence state of the constant current characteristic signal.
The signal injection circuit according to claim 1, characterized in that the signal injection circuit further includes a power module, and the constant current generating module is connected to a load;

The power module is used to obtain a DC voltage signal and a voltage stabilization signal according to the AC voltage signal of the low-voltage power station area, and output the DC voltage signal and the voltage stabilization signal to the constant current generating module to pass The constant current generating module supplies power to the load;

The constant current generating module is used to make the load work in the constant current region when in the conduction state, and obtain the constant current characteristic signal indicating that the load operates in the constant current region.
The signal injection circuit according to claim 2, wherein the power module includes a rectification unit and a voltage stabilizing unit;

The rectification unit is used to rectify the AC voltage signal to obtain the DC voltage signal and output it to the voltage stabilizing unit and the constant current generating module respectively;

The voltage stabilizing unit is used to stabilize the DC voltage signal, and output the stabilized voltage signal to the constant current generating module.
The signal injection circuit according to claim 2 or 3, characterized in that the constant current generating module includes a first switch unit, a second switch unit and a first isolation switch unit;

The first isolation switch unit is used to switch working states according to the frequency drive signal, and when the first isolation switch unit is in a conductive state, output a drive control signal to the first switch unit;

The second switch unit is used to obtain a constant voltage signal according to the voltage stabilization signal, and conducts when the first switch unit is turned on, and outputs the constant voltage signal to the first switch unit;

The first switch unit is configured to be turned on according to the drive control signal to output the constant voltage signal to the load, and to output the constant current characteristic signal indicating that the load is operating in the constant current region to The feedback module.
The signal injection circuit according to claim 4, characterized in that the first switch unit includes a first switch tube, the second switch unit includes a second switch tube, and the first isolation switch unit includes a first optical switch. coupling;

The anode of the light emitter of the first optocoupler receives the frequency drive signal, one end of the photoreceiver of the first optocoupler is connected to the reference ground, and the other end outputs the drive control signal to the gate of the first switch tube. pole;

The gate of the second switching tube receives the voltage stabilizing signal, and the source of the second switching tube outputs the constant voltage signal to the source of the first switching tube;

The drain of the first switch tube outputs the constant voltage signal to the load, and outputs the constant current characteristic signal to the feedback module.
The signal injection circuit according to claim 1, wherein the feedback module includes a second isolation switch unit;

When the second isolation switch unit is in the off state, a feedback signal based on the first level is obtained;

When the second isolation switch unit switches from the off state to the on state in response to the constant current characteristic signal, we get to a feedback signal based on the second level.
The signal injection circuit according to claim 6, characterized in that the feedback module further includes a conversion unit, the conversion unit is connected to the constant current generating module and the second isolation switch unit respectively, and the conversion unit For converting the constant current characteristic signal into a feedback control signal and outputting it to the second isolation switch unit.
The signal injection circuit according to claim 7, wherein the conversion unit includes a twelfth resistor, the second isolation switch unit includes a second optocoupler, and one end of the twelfth resistor receives the constant The other end outputs the feedback control signal to the anode of the light emitter of the second optocoupler, and the light receiver of the second optocoupler outputs the feedback signal.
The signal injection circuit according to claim 1, characterized in that the signal injection circuit further includes a control unit, the control unit is connected to the constant current generating module and the feedback module respectively;

The control unit is configured to inject the frequency drive signal into the constant current generating module of the target node in response to the injection signal of the main station of the low-voltage power station area, and determine based on the feedback signal output by the feedback module The occurrence state of the constant current characteristic signal.
A signal injection method, characterized in that it is applied to the signal injection circuit according to any one of claims 1 to 9, and the method includes:

The constant current generating module of the signal injection circuit switches working state according to the frequency drive signal. When the constant current generating module is in the on state, it outputs a constant current characteristic signal to the feedback module of the signal injection circuit; the frequency drive The signal is a signal used to identify the physical topology of the low-voltage power station area;

The feedback module adjusts a feedback signal according to the constant current characteristic signal; the feedback signal is used to reflect the occurrence state of the constant current characteristic signal.