A line protection device and an inverter

Abstract

The utility model provides a kind of line protection device and inverter, it is related to circuit protection technical field.In the utility model, line protection device is applied to the power supply line between the output port of inverter and access port connection, line protection device includes: the current sampling circuit, control circuit and current regulating circuit connected in turn;Among them, current sampling circuit is used to sample the power supply current of power supply line and generate sampling current, control circuit is used to access sampling current, and control signal is generated based on sampling current and preset reference voltage;Control signal is used to increase the on-resistance of current regulating circuit, so that the current value of power supply current is less than preset current threshold;Current regulating circuit includes first adjusting module and second adjusting module respectively arranged on power supply line, first adjusting module and second adjusting module are connected in series, one end of first adjusting module is connected with output port.In this way, the speed and accuracy of line protection are improved.

Description

Technical Field

[0001] This utility model relates to the field of circuit protection technology, and in particular to a line protection device and an inverter. Background Technology

[0002] In existing power supply systems (such as photovoltaic power supply systems), inverters can typically convert direct current (DC) to alternating current (AC) and supply the AC to the off-grid (or independent grid) to enable off-grid power supply to the load. That is, the output of the inverter is directly or indirectly connected to the off-grid.

[0003] When a load (such as a capacitive load or a motor load) is connected to the inverter's input port, a large inrush current typically occurs in the power supply line between the inverter's output port and the input port. In this case, the power supply system uses a control module (such as a microcontroller unit, MCU) to detect the overcurrent time of the power supply line to determine if the power supply line is in a short-circuit state, and provides short-circuit protection when it is determined that the power supply line is in a short-circuit state.

[0004] However, with the aforementioned line protection method, the control module takes a considerable amount of time to determine whether the power supply line is in a short-circuit state based on the overcurrent time, resulting in an inability to promptly limit the power supply current in the power supply line. Furthermore, determining whether the power supply line is in a short-circuit state based on the overcurrent time and the time threshold set for the overcurrent time may lead to inaccurate determinations. For example, if the aforementioned time threshold is too short, it may cause the electrical equipment to fail to start normally, i.e., the power supply line is judged to be in a short-circuit state when the surge current output by the energized equipment is normally starting up. As another example, if the aforementioned time threshold is too long, the surge current flowing through the electrical equipment for an extended period may damage the equipment.

[0005] Therefore, improving the speed and accuracy of line protection is an urgent problem to be solved. Utility Model Content

[0006] This utility model provides a line protection device and inverter to improve the speed and accuracy of line protection.

[0007] In a first aspect, this utility model provides a line protection device applied to a power supply line connecting the output port and the input port of an inverter. The input port is a port of the power grid and / or a load used to connect to the inverter. The power supply line is used to transmit power. The line protection device includes a current sampling circuit, a control circuit, and a current regulation circuit connected in sequence. The current sampling circuit is connected to the power supply line, and the current sampling circuit is used to sample the power supply current of the power supply line and output the sampled current. The control circuit is used to receive the sampled current and generate a control signal for the current regulation circuit based on the sampled current and a preset reference voltage; the control signal is used to increase the on-resistance of the current regulation circuit so that the current value of the supply current is less than a preset current threshold. The current regulation circuit includes a first regulation module and a second regulation module respectively disposed on the power supply line. The first regulation module and the second regulation module are connected in series. One end of the first regulation module is connected to the output port. The current regulation circuit is used to increase the on-resistance of the first regulation module based on the control signal when the power supply current flows from the output port to the access port, so that the current value of the power supply current is less than the preset current threshold; or, when the power supply current flows from the access port to the output port, increase the on-resistance of the second regulation module based on the control signal, so that the current value of the power supply current is less than the preset current threshold.

[0008] In a second aspect, this utility model embodiment provides an inverter, which includes: an output port, an input port, a power supply line, and a line protection device as described in the first aspect; The power supply line is connected between the output port and the access port, and is used to transmit power. The line protection device is used to protect the power supply line.

[0009] The beneficial effects of this utility model are as follows: In the line protection device provided in this embodiment of the invention, the current value of the power supply current flowing through the power supply line is determined by sampling the power supply line connecting the output port and the input port of the inverter through a current sampling circuit. Then, after the control circuit receives the sampled current output from the current sampling circuit, a control signal is generated based on the sampled current and a preset reference voltage to increase the on-resistance of the current regulation circuit, so that the power supply current value is less than a preset current threshold. Specifically, the current regulation circuit can be used to increase the on-resistance of the first regulation module in the current regulation circuit based on the control signal when the power supply current flows from the output port to the input port, so that the power supply current value is less than the preset current threshold; or, when the power supply current flows from the input port to the output port, to increase the on-resistance of the second regulation module in the current regulation circuit based on the control signal, so that the power supply current value is less than the preset current threshold.

[0010] This method can detect in a timely manner whether the power supply current on the power supply line exceeds the preset current threshold, thereby promptly determining whether there is an abnormality in the power supply current on the power supply line. Furthermore, the hardware protection of the power supply line implemented through the control circuit and the current adjustment circuit can adjust the power supply current on the power supply line in a timely manner according to the sampled current, which improves the speed and accuracy of line protection compared to the traditional line protection method (i.e., software protection of the power supply line).

[0011] Furthermore, other features and advantages of this invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described herein are used to provide a further understanding of this utility model, constitute a part of this utility model, and do not constitute an improper limitation of this utility model. In the accompanying drawings: Figure 1 This is a schematic diagram of the composition structure of a line protection device provided in an embodiment of the present utility model.

[0013] Figure 2 A schematic diagram of the composition structure of another line protection device provided in an embodiment of this utility model.

[0014] Figure 3 This is a schematic diagram of the composition structure of another line protection device provided in an embodiment of the present utility model.

[0015] Figure 4 A schematic diagram of the composition structure of another line protection device provided in an embodiment of this utility model.

[0016] Figure 5 A schematic diagram of the composition structure of another line protection device provided for an embodiment of this utility model.

[0017] Figure 6 A schematic diagram of the circuit structure of a line protection device provided in an embodiment of this utility model.

[0018] Figure 7 This is a schematic diagram of the composition structure of an inverter provided in an embodiment of the present utility model.

[0019] Reference numerals: 1 - Line protection device; 11 - Current sampling circuit; 12 - Control circuit; 121 - First control module; 1211 - First operational amplifier unit; 12111 - First reference voltage input subunit; 12112 - First sampling current input subunit; 12113 - First comparator subunit; 1212 - First voltage control unit; 1213 - First drive voltage output unit; 1214 - First buck unit; 122 - Second control module; 1221 - Second operational amplifier unit; 12211 - Second reference voltage input subunit; 12212 - Second sampling current input subunit; 12213 - Second comparator subunit; 1222 - Second voltage control unit; 1223 - Second drive voltage output unit; 1224 - Second buck unit; 13 - Current regulation circuit; 131 - First regulation module; 132 - Second regulation module; 2 - Power supply line; 3 - Output port; 4 - Input port; Q1 - First MOSFET; Q2 - Second MOSFET; Q3 - First transistor; Q4 - Second transistor; U1 - First operational amplifier; U2 - Second operational amplifier; F1 - First voltage feedback circuit; F2 - Second voltage feedback circuit; R1-1 and R2-1 - First resistors; R1-2 and R2-2 - Second resistors; R1-3 and R2-3 - Third resistors; R1-4 and R2-4 - Fourth resistors; R1-5 and R2-5 - Fifth resistors; R1-6 and R2-6 - Sixth resistors; R1-7 and R2-7 - Seventh resistors; C1, C2, C3, and C4 - Capacitors. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of the embodiments are shown in the accompanying drawings. Throughout the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] To enable those skilled in the art to better understand the solutions of this utility model, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. In the embodiments of this utility model, it should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0022] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] In the description of the embodiments of this utility model, the words "example" or "for example" are used to indicate exemplification, illustration, or description. Any embodiment or design described as "example" or "for example" in the embodiments of this utility model is not to be construed as being more preferred or having more advantages than another embodiment or design. The use of the words "example" or "for example" is intended to present relative concepts in a clear manner. Furthermore, "multiple" in the embodiments of this utility model refers to two or more; therefore, "multiple" can also be understood as "at least two" in the embodiments of this utility model. "At least one" can be understood as one or more, for example, one, two, or more. For example, including at least one means including one, two, or more, and is not limited to which ones are included. For example, including at least one of A, B, and C, then it can include A, B, C, A and B, A and C, B and C, or A and B and C.

[0024] It should be noted that in this embodiment of the invention, "and / or" describes the relationship between the associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / ", unless otherwise specified, generally indicates that the preceding and following associated objects have an "or" relationship. It should be pointed out that in this embodiment of the invention, "connection" can be understood as an electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0025] Furthermore, the names of the messages or information exchanged between the multiple devices in the embodiments of this utility model are for illustrative purposes only and are not intended to limit the scope of these messages or information.

[0026] The design concept of this utility model embodiment is briefly introduced below: In existing power supply systems (such as photovoltaic power supply systems), inverters typically convert direct current (DC) to alternating current (AC) and supply the AC power to the off-grid (or independent grid) to enable off-grid power supply to the load.

[0027] When a partial load is connected to the inverter's input port, a large inrush current typically occurs in the power supply line connecting the inverter's output port and the input port. In this case, the control module detects the overcurrent time of the power supply line to determine if the power supply line is in a short-circuit state, and performs short-circuit protection on the power supply line if a short-circuit condition is determined.

[0028] However, using the aforementioned line protection method, the control module takes a considerable amount of time to determine whether the power supply line is in a short-circuit state based on the overcurrent time, resulting in an inability to promptly limit the supply current in the power supply line. Furthermore, judging whether the power supply line is in a short-circuit state based on the overcurrent time and the time threshold set for the overcurrent time may lead to inaccurate judgments. For example, if the time threshold is too small, it may misjudge the surge current of a normal load startup as a problem with the power supply line; conversely, if the time threshold is too large, it will result in a long time for determining the power supply line's status, failing to provide timely protection. Therefore, improving the speed and accuracy of line protection is a pressing issue that needs to be addressed.

[0029] In view of this, in order to solve or improve the above-mentioned problems, this utility model provides a line protection device. See also... Figure 1As shown, the line protection device 1 can be applied to the power supply line 2 connecting the output port 3 and the input port 4 of the inverter. That is, the power supply line 2 is connected between the output port 3 and the input port 4, and the power supply line 2 can be used to transmit power. In other words, the line protection device 1 can provide line protection for the power supply line 2 connecting the output port 3 and the input port 4. Optionally, the input port 4 can be a port used by the power grid and / or load to connect to the inverter; this embodiment of the invention does not limit this. Figure 1 As shown, the line protection device 1 may include a current sampling circuit 11, a control circuit 12, and a current regulating circuit 13. The current sampling circuit 11, control circuit 12, and current regulating circuit 13 are connected sequentially, meaning the control circuit 12 is connected to both the current sampling circuit 11 and the current regulating circuit 13. Furthermore, the current sampling circuit 11 is connected to the power supply line 2, and the current regulating circuit 13 is mounted on the power supply line 2.

[0030] Optionally, the power supply line 2 can be a live wire (or phase wire, L wire), or a neutral wire (or neutral line, N wire), or a ground wire (or protective wire, PE wire). This embodiment of the utility model does not limit this.

[0031] The current sampling circuit 11 can be used to sample the supply current I of the power supply line 2. sup Perform sampling and output sampling current I sam Due to the sampling current I sam The magnitude of the current is related to the supply current I. sup The currents are the same, i.e., I sam = I sup Therefore, by sampling the current in the power supply line 2, the current sampling circuit 11 can accurately detect the supply current I in the power supply line 2. sup The magnitude of the current.

[0032] For example, the current sampling circuit 11 can sample the current of the power supply line 2 according to a set current sampling period (e.g., 30 seconds) to obtain the supply current I of the power supply line 2. sup The current value, i.e., the sampling current I. sam The current value.

[0033] Control circuit 12 can be used to connect the sampling current I sam And based on the sampled current I sam and the preset reference voltage V ref The control signal Signal.C for the current regulating circuit 13 is generated. The aforementioned control signal Signal.C can be used to increase the on-resistance of the current regulating circuit 13, thereby increasing the supply current I. sup The current value is less than the preset current threshold I. thThat is, through the current regulating circuit 13, the line protection device 1 can disconnect the power supply current I on the power supply line 2 when it detects an abnormality in the power supply current of the power supply line 2 (e.g., a short circuit occurs in the power supply line 2). sup Alternatively, limit the supply current I. sup The magnitude of the current is adjusted to achieve line protection for power supply line 2. It should be noted that when power supply line 2 is connected (i.e., current regulation circuit 13 is in the closed state), the on-resistance of current regulation circuit 13 can be considered as a variable resistor. Assume a preset current threshold I... th For 0.2A and supply current I sup The current value (or sampling current I) sam If the current value is 0.25 A, then the supply current I on power supply line 2 can be determined. sup The current value (i.e., 0.25 A) is greater than the preset current threshold I. th (i.e., 0.2 A). At this time, the control circuit 12 can control the current regulation circuit 13 to adjust the supply current I on the power supply line 2 through the control signal Signal.C. sup So that the supply current I on power supply line 2 sup The current value is less than the preset current threshold I. th For example, the power supply current I on the power supply line 2 after being adjusted by the control circuit 12 and the current adjustment circuit 13. sup The current value is 0.18 A.

[0034] Optional, such as Figure 1 As shown, the current regulation circuit 13 may include a first regulation module 131 and a second regulation module 132 respectively disposed on the power supply line 2. The first regulation module 131 and the second regulation module 132 are connected in series, that is, one end of the first regulation module 131 is connected to the output port 3, the other end of the first regulation module 131 is connected to one end of the second regulation module 132, and the other end of the second regulation module 132 is connected to the access port 4.

[0035] The current regulation circuit 13 can be used to adjust the supply current I sup When the power supply flows from output port 3 to input port 4, the on-resistance of the first adjustment module 131 is increased based on the control signal Signal.C, so as to increase the power supply current I. sup The current value is less than the preset current threshold I. th Or, in the supply current I sup When the power supply flows from access port 4 to output port 3, the on-resistance of the second regulation module 132 is increased based on the control signal Signal.C, so as to increase the power supply current I. sup The current value is less than the preset current threshold I. th .

[0036] It should be noted that the first adjustment module 131 controls the power supply current I. sup When the power supply is switched on or off or the voltage is increased, the second regulating module 132 will not control the power supply current I. sup The second regulating module 132 is in the on state, controlling the on / off state or the magnitude of the power supply current I. Similarly, the second regulating module 132 controls the power supply current I. sup When the power supply is switched on or off or the voltage is increased, the first regulating module 131 will not control the power supply current I. sup The on / off state or the magnitude, and the first adjustment module 132 is in the conducting state.

[0037] In addition, such as Figure 1 As shown, the first adjustment module 131 is located on the side closer to the output port 3, and the second adjustment module 132 is located on the side closer to the access port 4. Of course, the first adjustment module 131 can also be located on the side closer to the access port 4, and the second adjustment module 132 can also be located on the side closer to the output port 3. This embodiment of the present invention does not limit this.

[0038] based on Figure 1 The line protection device 1 shown uses a current sampling circuit 11 to sample the current of the power supply line 2 connecting the output port 3 and the input port 4 of the inverter, thereby determining the supply current I flowing through the power supply line 2. sup The current value. Next, the sampling current I output from the current sampling circuit 11 is connected to the control circuit 12. sam Then, based on the sampling current I sam and the preset reference voltage V ref A control signal Signal.C is generated to increase the on-resistance of the current regulation circuit 13, so that the supply current I... sup The current value is less than the preset current threshold I. th The current regulation circuit 13 can be used to adjust the supply current I. sup When the power supply current flows from output port 3 to input port 4, the on-resistance of the first adjustment module 131 in the current adjustment circuit 13 is increased based on the control signal Signal.C, so as to increase the supply current I. sup The current value is less than the preset current threshold I. th Or, in the supply current I sup When the power supply current flows from access port 3 to output port 4, the on-resistance of the second regulation module 132 in the current regulation circuit 13 is increased based on the control signal Signal.C, so as to increase the supply current I. sup The current value is less than the preset current threshold I. th .

[0039] In this way, the power supply current I on power supply line 2 can be detected in a timely manner. sup Does it exceed the preset current threshold I? thTherefore, the power supply current I on power supply line 2 can be determined. sup Is there any abnormality? Furthermore, the hardware protection of the power supply line 2, implemented through control circuit 12 and current regulation circuit 13, can be based on the sampled current I. sam Adjust the power supply current I on power supply line 2 in a timely manner. sam This improves the speed and accuracy of line protection. Furthermore, because line protection device 1 can quickly provide hardware line protection to power line 2, it also allows sufficient time for judgment compared to traditional software line protection methods.

[0040] In one alternative implementation, see [link to relevant documentation]. Figure 2 As shown, the first adjustment module 131 may include a first MOSFET Q1, and the second adjustment module 132 may include a second MOSFET Q2. The drain (D) of the first MOSFET Q1 is connected to the output port 3, the source (S) of the first MOSFET Q1 is connected to the source (S) of the second MOSFET Q2, and the drain of the second MOSFET Q2 is connected to the access port 4. In other words, both the first adjustment module 131 and the second adjustment module 132 may include an N-channel metal-oxide-semiconductor field-effect transistor (MOSFET). The two N-MOSFETs (i.e., the first MOSFET Q1 and the second MOSFET Q2) are connected in series back-to-back, forming a complementary conduction state.

[0041] At this time, in the supply current I sup When the power supply flows from output port 3 to input port 4, the first MOSFET Q1 is in the closed state and the second MOSFET Q2 is in the open state; that is, the initial state of the first MOSFET Q1 is closed and the initial state of the second MOSFET Q2 is open. Furthermore, when the supply current I... sup When the current flows from the access port 4 to the output port 3, the first MOSFET Q1 is in the off state and the second MOSFET Q2 is in the closed state. That is, the initial state of the first MOSFET Q1 is the off state and the initial state of the second MOSFET Q2 is the closed state.

[0042] It should be understood that the supply current I sup The current flowing from output port 3 to input port 4, i.e., the supply current I, is... sup The current flow direction is from output port 3 to input port 4. This current flow direction can also be referred to as the first current direction. Supply current I sup The current flowing from input port 4 to output port 3, i.e., the supply current I, is... supThe current flow direction is from input port 4 to output port 3. This current flow direction can also be called the second current direction. Along the first current direction, the supply current Isup flows sequentially through the drain and source terminals of the first MOSFET Q1, and the source and drain terminals of the second MOSFET Q2. Along the second current direction, the supply current Isup flows sequentially through the drain and source terminals of the second MOSFET Q2, and the source and drain terminals of the first MOSFET Q1. Therefore, through the first MOSFET Q1 and the second MOSFET Q2, the line protection device 1 can protect the power supply line 2 between the output port 3 and the input port 4 of the inverter when a supply current Isup flows in any current direction.

[0043] In one alternative implementation, it is still as follows Figure 2 As shown, the control circuit 12 may include a first control module 121 and a second control module 122. The first control module 121 is connected to both the first adjustment module 131 and the current sampling circuit 11, and the second control module 122 is electrically connected to both the second adjustment module 132 and the current sampling circuit 11.

[0044] The first control module 121 can be used to control the supply current I. sup The current flows from output port 3 to input port 4 (i.e., the supply current I). sup When the current flows in the first current direction, based on the sampled current I... sam and reference voltage V ref A first control signal, Signal.C.1, is generated. This first control signal, Signal.C.1, can be used to increase the on-resistance of the first adjustment module 131 (or the first MOSFET Q1) to increase the supply current I. sup The current value is less than the preset current threshold I. th .

[0045] The second control module 122 can be used to control the supply current I. sup The current flows from input port 4 to output port 3 (i.e., the supply current I). sup When the current flows in the direction of the second current (i.e., based on the sampled current I), sam and reference voltage V ref Generate a second control signal, Signal.C.2. This second control signal, Signal.C.2, can be used to increase the on-resistance of the second adjustment module 132 (or the second MOSFET Q2) to increase the supply current I. sup The current value is less than the preset current threshold I. th .

[0046] Based on the above method, the line protection device 1, through the first control module 121 and the first adjustment module 131 (or the first MOSFET Q1), can adjust the supply current I...sup When the current flows in the first current direction, line protection is provided for power supply line 2. Furthermore, the line protection device 1, through the second control module 122 and the second adjustment module 132 (or the second MOSFET Q2), can adjust the supply current I... sup When the current flows in the direction of the second current, line protection is provided for power supply line 2.

[0047] In one alternative implementation, see [link to relevant documentation]. Figure 3 As shown, the first control module 121 in the control circuit 12 may include a first operational amplifier unit 1211 and a first voltage control unit 1212. The output terminal of the first operational amplifier unit 1211 is connected to the first terminal of the first voltage control unit 1212, the second terminal of the first voltage control unit 1212 is connected to the first adjustment module 131, and the third terminal of the first voltage control unit 1212 can be used to ground (GND).

[0048] The first operational amplifier unit 1211 can be used to connect to a reference voltage V. ref and sampling current I sam It outputs a first comparison voltage V1. The first voltage control unit 1212 can be used to output a first comparison voltage V1 greater than a preset voltage threshold V. th At that time, a first control signal Signal.C.1 is generated, and the drive voltage V of the control terminal (e.g., the gate of the first MOSFET Q1) of the first adjustment module 131 is adjusted based on the first control signal Signal.C.1. dri That is, reducing the drive voltage V at the control terminal of the first adjustment module 131. dri This increases the on-resistance of the first adjustment module 131. At this time, the supply current I on the power supply line 2... sup The current value decreases, thus achieving line protection for power supply line 2.

[0049] Still Figure 3 As shown, the second control module 122 in the control circuit 12 may include: a second operational amplifier unit 1221 and a second voltage control unit 1222. The output terminal of the second operational amplifier unit 1221 is connected to the first terminal of the second voltage control unit 1222, the second terminal of the second voltage control unit 1222 is connected to the second adjustment module 132, and the third terminal of the second voltage control unit 1222 can be used to ground (GND).

[0050] The second operational amplifier unit 1221 can be used to connect to the reference voltage V. ref and sampling current I sam The second voltage control unit 1222 can be used to output a second comparison voltage V2 when the second comparison voltage V2 is greater than a preset voltage threshold V. thAt that time, a second control signal Signal.C.2 is generated, and the drive voltage V of the control terminal (e.g., the gate of the second MOSFET Q2) of the second adjustment module 132 is adjusted based on the second control signal Signal.C.2. dri That is, reducing the drive voltage V at the control terminal of the second adjustment module 132. dri This increases the on-resistance of the second adjustment module 132. At this time, the supply current I on the power supply line 2... sup The size is reduced, thus achieving line protection for power supply line 2.

[0051] In one alternative implementation, see [link to relevant documentation]. Figure 4 As shown, the first operational amplifier unit 1211 may include: a first reference voltage input subunit 12111, a first sampling current input subunit 12112, and a first comparator subunit 12113. One end of the first reference voltage input subunit 12111 is used to input a reference voltage V. ref One end of the first sampling current input subunit 12112 is used to input the sampling current I. sam The negative input terminal of the first comparator subunit 12113 is connected to the first reference voltage input subunit 12111, the positive input terminal of the first comparator subunit 12113 is connected to the first sampling current input subunit 12112, and the output terminal of the first comparator subunit 12113 is used as the output terminal of the first operational amplifier unit 1211.

[0052] Still Figure 4 As shown, the second operational amplifier unit 1221 may include: a second reference voltage input subunit 12211, a second sampling current input subunit 12212, and a second comparator subunit 12213. One end of the second reference voltage input subunit 12211 can be used to input a reference voltage V. ref One end of the second sampling current input subunit 12212 can be used to input the sampling current I. sam The positive input terminal of the second comparator subunit 12213 is connected to the second reference voltage input subunit 12211, the negative input terminal of the second comparator subunit 12213 is connected to the second sampling current input subunit 12212, and the output terminal of the second comparator subunit 12213 is used as the output terminal of the second operational amplifier unit 1221.

[0053] In one alternative implementation, it is still as follows Figure 4 As shown, the first control module 121 may further include a first drive voltage output unit 1213. The first drive voltage output unit 1213 is connected to the control terminal of the first adjustment module 131 and the second terminal of the first voltage control unit 1212, respectively. And / or, as shown... Figure 4As shown, the second control module 122 may further include a second drive voltage output unit 1223. The second drive voltage output unit 1223 is connected to the control terminal of the second adjustment module 132 and the second terminal of the second voltage control unit 1222, respectively.

[0054] The first drive voltage output unit 1213 can be used to output the drive voltage V at the control terminal of the first adjustment module 131. dri This is to enable the first adjustment module 131 to conduct. It should be understood that, in the absence of a power surge on power line 2, when the control terminal of the first adjustment module 131 is connected to the drive voltage V output by the first drive voltage output unit 1213... dri At that time, the current flowing through power supply line 2 is less than the preset current threshold I. th Supply current I sup .

[0055] The second drive voltage output unit 1223 can be used to output the drive voltage V at the control terminal of the second adjustment module 132. dri This is to enable the second adjustment module 132 to conduct. Similarly, when there is no power surge on power supply line 2, and the control terminal of the second adjustment module 132 is connected to the drive voltage V output by the second drive voltage output unit 1223, the second adjustment module 132 will be activated. dri At that time, the current flowing through power supply line 2 is less than the preset current threshold I. th Supply current I sup .

[0056] Optionally, the drive voltage output units (i.e., the first drive voltage output unit 1213 and the second drive voltage output unit 1223) in the first control module 121 and the second control module 122 can be the same drive voltage output unit.

[0057] In one alternative implementation, see [link to relevant documentation]. Figure 5 As shown, the first voltage control unit 1212 may include a first transistor Q3, and / or the second voltage control unit 1222 may include a second transistor Q4. The collector (C) of the first transistor Q3 is connected to the gate (G) of the first MOSFET Q1, the base (B) of the first transistor Q3 is connected to the first comparator subunit 12113, and the emitter (E) of the first transistor Q3 can be used to ground (GND). The collector (C) of the second transistor Q4 is connected to the gate (G) of the second MOSFET Q2, the base (B) of the second transistor Q4 is connected to the second comparator subunit 12213, and the emitter (E) of the second transistor Q4 can be used to ground (GND). In other words, both the first voltage control unit 1212 and the second voltage control unit 1222 may include NPN transistors.

[0058] In one alternative implementation, it is still as follows Figure 5 As shown, the first control module 121 may further include a first voltage drop unit 1214, and the second control module 122 may further include a second voltage drop unit 1224. The first voltage drop unit 1214 is connected to the output terminal of the first operational amplifier unit 1211 and the first terminal of the first voltage control unit 1212, respectively. The second voltage drop unit 1224 is connected to the output terminal of the second operational amplifier unit 1221 and the first terminal of the second voltage control unit 1222, respectively. Optionally, both the first voltage drop unit 1214 and the second voltage drop unit 1224 may include a first resistor and a second resistor.

[0059] like Figure 5 As shown, one end of the first resistor R1-1 is connected to the output terminal of the first operational amplifier unit 1211, and the other end of the first resistor R1-1 is connected to one end of the second resistor R1-2 and the first terminal of the first voltage control unit 1212, respectively. The other end of the second resistor R1-2 is used for grounding. For example, the formula for calculating the voltage at the first terminal of the first voltage control unit 1212 after the first comparison voltage V1 is dropped by the first voltage drop unit 1214 can be specifically expressed as follows:

[0060] in, This indicates the voltage value at the first terminal of the first voltage control unit 1212. This indicates the resistance value of the first resistor, R1-1. This indicates the resistance value of the second resistor R1-2. This represents the voltage value of the first comparison voltage V1.

[0061] At this time, the first voltage control unit 1212 can be used when the voltage at the first terminal of the first voltage control unit 1212 is greater than a preset voltage threshold V. th At that time, a first control signal Signal.C.1 is generated, and the drive voltage V at the control terminal of the first adjustment module 131 is reduced based on the first control signal Signal.C.1. dri Increase the on-resistance of the first adjustment module 131, thereby reducing the supply current I on the power supply line 2. sup This enables line protection for power supply line 2.

[0062] Still Figure 5As shown, one end of the first resistor R2-1 is connected to the output terminal of the operational amplifier unit 1221, and the other end of the first resistor R2-1 is connected to one end of the second resistor R2-2 and the first terminal of the second voltage control unit 1222. The other end of the second resistor R2-2 is used for grounding. It should be understood that the calculation formula for the voltage at the first terminal of the first voltage control unit 1212 after the first comparison voltage V1 is reduced by the first voltage drop unit 1214 is the same as the calculation formula for the voltage at the first terminal of the second voltage control unit 1222 after the first comparison voltage V2 is reduced by the second voltage drop unit 1224, so it will not be repeated here.

[0063] At this time, the second voltage control unit 1222 can be used when the voltage at the first terminal of the second voltage control unit 1212 is greater than a preset voltage threshold V. th At that time, a second control signal Signal.C.2 is generated, and the drive voltage V at the control terminal of the second adjustment module 132 is reduced based on the second control signal Signal.C.2. dri Increase the on-resistance of the second adjustment module 132, thereby reducing the supply current I on the power supply line 2. sup This enables line protection for power supply line 2.

[0064] In one alternative implementation, it is still as follows Figure 5 As shown, both the first sampling current input subunit 12112 and the second reference voltage input subunit 12211 may include a third resistor and a fourth resistor.

[0065] In this circuit, one end of the third resistor R1-3 in the first sampling current input subunit 12112 is connected to the current sampling circuit 11. The other end of the third resistor R1-3 is connected to the first input terminal of the first operational amplifier unit 1211 (i.e., the positive input terminal of the first comparator subunit 12113) and one end of the fourth resistor R1-4 in the first sampling current input subunit 12112. The other end of the fourth resistor R1-4 is grounded. Therefore, the voltage value at the positive input terminal of the first comparator subunit 12113 is the voltage value between the third resistor R1-3 and the fourth resistor R1-4. The formula for calculating the voltage value at the positive input terminal of the first comparator subunit 12113 can be specifically expressed as follows:

[0066] in, This represents the voltage value at the positive input terminal of the first comparator subunit 12113. Indicates the sampling current I sam The current value, This indicates the resistance value of the fourth resistor, R1-4.

[0067] One end of the third resistor R2-3 in the second reference voltage input subunit 12211 is used to connect the reference voltage. The other end of the third resistor R2-3 is connected to the first input terminal of the second operational amplifier unit 1221 (i.e., the positive input terminal of the second comparator subunit 12213) and one end of the fourth resistor R2-4 in the second reference voltage input subunit 12211, respectively. The other end of the fourth resistor R2-4 is used for grounding. Therefore, the voltage value at the positive input terminal of the second comparator subunit 12213 is the voltage value between the third resistor R2-3 and the fourth resistor R2-4. The formula for calculating the voltage value at the positive input terminal of the second comparator subunit 12213 can be specifically expressed as follows:

[0068] in, This indicates the voltage value at the positive input terminal of the second comparator subunit 12213. Indicates the sampling current I sam The current value, This indicates the resistance value of the third resistor, R2-3. This indicates the resistance value of the fourth resistor, R2-4.

[0069] In one alternative implementation, it is still as follows Figure 5 As shown, the first comparator subunit 12113 includes a first operational amplifier U1 and a first voltage feedback line F1. The first input terminal (i.e., the positive input terminal of the first operational amplifier U1) is connected to the first reference voltage input subunit 12111, and the second input terminal (i.e., the negative input terminal of the first operational amplifier U1) is also connected to the first reference voltage input subunit 12111. The first voltage feedback line F1 is electrically connected to both the second input terminal and the output terminal of the first operational amplifier U1. The first operational amplifier U1 can be used to input a reference voltage V. ref and sampling current I sam And based on the reference voltage V ref and sampling current I sam The output voltage is a first comparison voltage V1. The first voltage feedback line F1 can be used to gradually increase the output voltage of the first operational amplifier U1 from 0 to the first comparison voltage V1. In this way, by gradually increasing the output voltage of the first operational amplifier U1 through the first voltage feedback line F1, the circuit safety of the first control module 121 is improved.

[0070] The second comparator subunit 12213 includes a second operational amplifier U2 and a second voltage feedback line F2. The first input terminal (i.e., the positive input terminal of the second operational amplifier U2) is connected to the second reference voltage input subunit 12211, and the second input terminal (i.e., the negative input terminal of the second operational amplifier U2) is also connected to the second reference voltage input subunit 12211. The second voltage feedback line F2 is electrically connected to both the second input terminal of the second operational amplifier U2 and the output terminal of the first operational amplifier U2. The second operational amplifier U2 can be used to input a reference voltage V. ref and sampling current I sam And based on the reference voltage V ref and sampling current I sam The output voltage V2 is a second comparison voltage. The second voltage feedback line F2 can be used to gradually increase the output voltage of the second operational amplifier U2 from 0 to the second voltage V2. In this way, by gradually increasing the output voltage of the second operational amplifier U2 through the second voltage feedback line F2, the circuit safety of the second control module 122 is improved.

[0071] In one optional implementation, both the first voltage feedback line F1 and the second voltage feedback line F2 may include a fifth resistor and a capacitor. Specifically, one end of the fifth resistor R1-5 in the first voltage feedback line F1 is connected to the second input terminal of the first operational amplifier U1, and the other end of the fifth resistor R1-5 is connected to one end of the capacitor C1 in the first voltage feedback line F1. The other end of the capacitor C1 is connected to the output terminal of the first operational amplifier U1.

[0072] Additionally, one end of the fifth resistor R2-5 in the second voltage feedback circuit F2 is connected to the second input terminal of the second operational amplifier U2, and the other end of the fifth resistor R2-5 is connected to one end of the capacitor C2 in the second voltage feedback circuit F2, and the other end of the capacitor C2 is electrically connected to the output terminal of the second operational amplifier U2.

[0073] In one optional implementation, the first reference voltage input subunit 12111 includes a sixth resistor R1-6, and the second sampling current input subunit 12212 includes a sixth resistor R2-6. The sixth resistors R1-6 and R2-6 are current-limiting resistors. Furthermore, a seventh resistor R1-7 can be provided between the first drive voltage output unit 1213 and the control terminal of the first adjustment module 131, and a seventh resistor R2-7 can be provided between the second drive voltage output unit 1223 and the control terminal of the second adjustment module 132, wherein the seventh resistors R1-7 and R2-7 are current-limiting resistors. It should be noted that after providing the seventh resistor R1-7 between the first drive voltage output unit 1213 and the control terminal of the first adjustment module 131, and after providing the seventh resistor R2-7 between the second drive voltage output unit 1223 and the control terminal of the second adjustment module 132, the voltage input to the control terminal of the first adjustment module 131 is the drive voltage after the voltage drop across the seventh resistor R1-7. The voltage connected to the control terminal of the second adjustment module 132 is the driving voltage after the voltage drop through the seventh resistor R2-7. .

[0074] It is understandable that the seventh resistor R1-7, which is provided between the first drive voltage output unit 1213 and the control terminal of the first adjustment module 131, can adjust the drive voltage V at the control terminal of the first adjustment module 131 by the first voltage control unit 1212. dri At the same time, ensure the circuit safety between the first drive voltage output unit 1213 and the first voltage control unit 1212.

[0075] Similarly, the seventh resistor R2-7, provided between the control terminal of the second drive voltage output unit 1223 and the second adjustment module 132, can adjust the drive voltage V at the control terminal of the second adjustment module 132 by the second drive voltage output unit 1223. dri At the same time, ensure the safety of the circuit between the second drive voltage output unit 1223 and the second voltage control unit 1222.

[0076] In one alternative implementation, the first sampling current input subunit 12112 may further include a capacitor C3 connected in parallel with the fourth resistor R1-4, and the second reference voltage input subunit 12211 may further include a capacitor C4 connected in parallel with the fourth resistor R2-4. The capacitors C3 and C4 can be used for filtering, decoupling, bypassing high-frequency noise, and isolating electrostatic interference, etc.

[0077] Based on the design principle of the line protection device 1 described above, refer to... Figure 6As shown, taking the first adjustment module 131 and the second adjustment module 132 as examples where both are N-MOSFETs (i.e., the first MOSFET Q1 and the second MOSFET Q2), and the first voltage control unit 1212 and the second voltage control unit 1222 as examples where both are NPN transistors (i.e., the first transistor Q3 and the second transistor Q4), the sampling current I... sam After voltage division by the third resistor R1-3 and the fourth resistor R1-4, if the voltage connected to the second input terminal of the first operational amplifier U1... If the voltage is higher than the voltage connected to the first input terminal, the output voltage of the first operational amplifier U1 (i.e., the first comparison voltage V1) gradually changes from low to high. The output voltage of the first operational amplifier U1 will drive the first transistor Q3 from the cutoff region to the amplification region, and the first MOSFET Q1 from the saturation region to the variable resistance region. At this time, the supply current of power supply line 2 will be limited. Similarly, the reference voltage V... ref After voltage division by the third resistor R2-3 and the fourth resistor R2-4, if the voltage connected to the first input terminal of the second operational amplifier U2... If the voltage is higher than the voltage connected to the second input terminal, the output voltage of the second operational amplifier U2 (i.e., the second comparison voltage V2) will gradually change from low level to high level. The output voltage of the second operational amplifier U2 will drive the second transistor Q4 from the cutoff region to the amplification region, and the second MOSFET Q2 from the saturation region to the variable resistance region. At this time, the supply current of the power supply line 2 will be limited.

[0078] Furthermore, by Figure 6 It can be seen that the power supply current I on power supply line 2 sup After the line protection process by line protection device 1, the power supply current I on power supply line 2 sup The stable current value (i.e. the power supply current value after line protection) is determined by the third resistor R1-3 and the fourth resistor R1-4 (or the third resistor R2-3 and the fourth resistor R2-4).

[0079] In summary, in the line protection device provided by this embodiment of the invention, the current value of the power supply current flowing through the power supply line connected between the output port and the input port of the inverter is determined by sampling the current through the current sampling circuit. Then, after the control circuit receives the sampled current output from the current sampling circuit, a control signal is generated based on the sampled current and a preset reference voltage to increase the on-resistance of the current regulation circuit, so that the power supply current value is less than a preset current threshold. Specifically, the current regulation circuit can be used to increase the on-resistance of the first regulation module in the current regulation circuit based on the control signal when the power supply current flows from the output port to the input port, so that the power supply current value is less than the preset current threshold; or, when the power supply current flows from the input port to the output port, to increase the on-resistance of the second regulation module in the current regulation circuit based on the control signal, so that the power supply current value is less than the preset current threshold. This method can detect in a timely manner whether the power supply current on the power supply line exceeds the preset current threshold, thereby promptly determining whether there is an abnormality in the power supply current on the power supply line. Furthermore, the hardware protection of the power supply line implemented through the control circuit and the current adjustment circuit can adjust the power supply current on the power supply line in a timely manner according to the sampled current, which improves the speed and accuracy of line protection compared to the traditional line protection method (i.e., software protection of the power supply line).

[0080] This utility model embodiment also provides an inverter. See also... Figure 7 As shown, the inverter X may include: Figure 1-7 The circuit protection device 1, power supply line 2, output port 3, and access port 4 are shown.

[0081] In this configuration, power supply line 2 is connected between output port 3 and input port 4. Power supply line 2 is used to transmit power, and line protection device 1 can be used to protect power supply line 2. By using this method, the line protection device 1 protects power supply line 2, improving the speed and accuracy of line protection.

[0082] Furthermore, it should be understood that the above-disclosed embodiments are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with reference to preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present utility model without departing from the content of the technical solution described in the present utility model shall still fall within the scope of the present utility model.

Claims

1. A line protection device, characterized in that, A power supply line is used to connect the output port and the input port of an inverter. The input port is a port on the power grid and / or a load used to connect to the inverter. The power supply line is used to transmit power. The line protection device includes a current sampling circuit, a control circuit, and a current regulation circuit connected in sequence. The current sampling circuit is connected to the power supply line, and the current sampling circuit is used to sample the power supply current of the power supply line and generate a sampling current. The control circuit is used to receive the sampled current and generate a control signal for the current regulation circuit based on the sampled current and a preset reference voltage; the control signal is used to increase the on-resistance of the current regulation circuit so that the current value of the supply current is less than a preset current threshold. The current regulation circuit includes a first regulation module and a second regulation module respectively disposed on the power supply line. The first regulation module and the second regulation module are connected in series. One end of the first regulation module is connected to the output port. The current regulation circuit is used to increase the on-resistance of the first regulation module based on the control signal when the power supply current flows from the output port to the access port, so that the current value of the power supply current is less than the preset current threshold; or, when the power supply current flows from the access port to the output port, increase the on-resistance of the second regulation module based on the control signal, so that the current value of the power supply current is less than the preset current threshold.

2. The line protection device as described in claim 1, characterized in that, The first adjustment module includes a first MOSFET, and the second adjustment module includes a second MOSFET. The drain of the first MOSFET is connected to the output port, the source of the first MOSFET is connected to the source of the second MOSFET, and the drain of the second MOSFET is connected to the input port. When the power supply current flows from the output port to the access port, the first MOSFET is in a closed state and the second MOSFET is in a closed state. Furthermore, when the power supply current flows from the access port to the output port, the first MOSFET is in the off state and the second MOSFET is in the closed state.

3. The line protection device as described in claim 2, characterized in that, The control circuit includes: a first control module and a second control module; wherein... The first control module is connected to the first adjustment module and the current sampling circuit respectively. The first control module is used to generate a first control signal based on the sampled current and the reference voltage when the power supply current flows from the output port to the access port. The first control signal increases the on-resistance of the first adjustment module so that the current value of the power supply current is less than the preset current threshold. The second control module is connected to the second adjustment module and the current sampling circuit respectively. The second control module is used to generate a second control signal based on the sampled current and the reference voltage when the power supply current flows from the access port to the output port. The second control signal increases the on-resistance of the second adjustment module so that the current value of the power supply current is less than the preset current threshold.

4. The line protection device as described in claim 3, characterized in that, The first control module includes: a first operational amplifier unit and a first voltage control unit; wherein, The output terminal of the first operational amplifier unit is connected to the first terminal of the first voltage control unit. The first operational amplifier unit is used to receive the reference voltage and the sampling current, and output a first comparison voltage. The second terminal of the first voltage control unit is connected to the first adjustment module, the third terminal of the first voltage control unit is grounded, and the first voltage control unit is used to generate the first control signal when the first comparison voltage is greater than a preset voltage threshold.

5. The line protection device as described in claim 4, characterized in that, The first operational amplifier unit includes: The first reference voltage access subunit has one end used to connect to the reference voltage; The first sampling current is connected to the sub-unit, and one end is used to connect the sampling current; The first comparator subunit has its negative input terminal connected to the first reference voltage input subunit and its positive input terminal connected to the first sampling current input subunit. The output terminal of the first comparator subunit is used as the output terminal of the first operational amplifier unit.

6. The line protection device as described in claim 5, characterized in that, The second control module includes: a second operational amplifier unit and a second voltage control unit; wherein, The output terminal of the second operational amplifier unit is connected to the first terminal of the second voltage control unit. The second operational amplifier unit is used to receive the reference voltage and the sampling current, and output a second comparison voltage. The second terminal of the second voltage control unit is connected to the second adjustment module, the third terminal of the second voltage control unit is grounded, and the second voltage control unit is used to generate the second control signal when the second comparison voltage is greater than the preset voltage threshold.

7. The line protection device as described in claim 6, characterized in that, The second operational amplifier unit includes: The second reference voltage access subunit has one end used to connect to the reference voltage. The second sampling current access subunit has one end used to access the sampling current. The second comparator subunit has its negative input terminal connected to the second sampling current input subunit and its positive input terminal connected to the second reference voltage input subunit. The output terminal of the second comparator subunit is used as the output terminal of the second operational amplifier unit.

8. The line protection device as described in claim 6 or 7, characterized in that, The first control module further includes: The first driving voltage output unit is connected to the control terminal of the first regulating module and the second terminal of the first voltage control unit, respectively. The first driving voltage output unit is used to output the driving voltage of the control terminal of the first regulating module so as to turn on the first regulating module. And / or, the second control module further includes: The second drive voltage output unit is connected to the control terminal of the second regulation module and the second terminal of the second voltage control unit, respectively. The second drive voltage output unit is used to output the drive voltage of the control terminal of the second regulation module so as to turn on the second regulation module.

9. The line protection device as described in claim 7, characterized in that, The first voltage control unit includes: a first transistor, the collector of the first transistor being connected to the gate of the first MOS transistor, the base of the first transistor being connected to the first comparator subunit, and the emitter of the first transistor being grounded; And / or, the second voltage control unit includes: a second transistor, the collector of the second transistor being connected to the gate of the second MOS transistor, the base of the second transistor being connected to the second comparator subunit, and the emitter of the second transistor being grounded.

10. An inverter, characterized in that, include: An output port, an access port, a power supply line, and a line protection device as described in any one of claims 1-9; wherein the power supply line is connected between the output port and the access port, the power supply line is used to transmit power, and the line protection device is used to protect the power supply line.

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