Inverter wiring detection circuit and inverter

Abstract

The utility model discloses an inverter wiring detection circuit and an inverter, and belongs to the technical field of inverters. Comprising a controllable load unit, a voltage detection unit and a control unit, the controllable load unit comprises three load branches formed by connecting a control switch and a power load in series, and the load branches are connected between any phase alternating current output end of the inverter and a zero line output end; the voltage detection unit comprises three voltage sampling loops which are respectively connected with the corresponding load branches in parallel and are used for detecting the voltage of the load branches in real time; and the control unit is connected with the controllable load unit and the voltage detection unit, and is used for controlling on and off of a control switch in the controllable load unit and receiving voltage sampling data obtained by the voltage detection unit. According to the utility model, the detection circuit is integrated in the inverter, so that wiring state diagnosis and active problem discovery can be carried out after installation and before formal power-on operation, and the trouble of passive troubleshooting afterwards is avoided.

Description

Technical Field

[0001] This utility model relates to the field of inverter technology, and in particular to an inverter wiring detection circuit and an inverter. Background Technology

[0002] During the on-site installation and commissioning of three-phase four-wire inverters, the wiring reliability of the AC output terminals (L1 / L2 / L3 / N) is crucial. Currently, installation work mainly relies on the experience and sense of responsibility of the installers, and the following problems often exist:

[0003] 1. Missing live or neutral wire: Due to negligence, workers may completely forget to connect one of the phases.

[0004] 2. Poor neutral wire contact: Loose terminals or loose wire connections can cause excessive resistance in the neutral wire connection, resulting in a "loose connection." When the inverter is under no-load or with a three-phase balanced load, there will be a virtual neutral voltage, making it impossible for sampling to detect wiring abnormalities.

[0005] The aforementioned problems are difficult to detect visually during the initial power-on phase, but they can cause abnormal fluctuations in the phase voltage at the inverter's AC output, deviating significantly from the rated value (e.g., 220V). This can prevent the inverter from starting up and connecting to the grid normally, and may even damage internal inverter components or connected downstream electrical equipment. Existing solutions typically involve post-incident troubleshooting, requiring professionals to use multimeters and other tools for measurement, which is inefficient, delays the project, and increases maintenance costs. Therefore, there is an urgent need for a detection mechanism that can be integrated into the inverter to quickly diagnose the wiring status before power-on or during the initial operation phase. Utility Model Content

[0006] To address the shortcomings of existing technologies, this invention integrates a detection circuit inside the inverter, enabling wiring status diagnosis after installation and before formal power-on operation. This proactively identifies problems and eliminates faults in their early stages, avoiding the hassle of reactive troubleshooting afterward.

[0007] To achieve the above objectives, this utility model provides an inverter wiring detection circuit, including: a controllable load unit, a voltage detection unit, and a control unit;

[0008] The controllable load unit includes three load branches consisting of a control switch and a power load connected in series, which are connected between any phase AC output terminal and the neutral output terminal of the inverter.

[0009] The voltage detection unit includes three voltage sampling circuits, which are connected in parallel with the corresponding load branches to detect the voltage of the load branches in real time.

[0010] The control unit connects the controllable load unit and the voltage detection unit, and is used to control the on and off of the control switch in the controllable load unit and to receive voltage sampling data obtained from the voltage detection unit.

[0011] Furthermore, the power loads in the three load branches include the following forms: all are resistive loads, all are capacitive loads, all are inductive loads, or mixed loads; the mixed loads are random combinations of resistive loads, capacitive loads, and inductive loads.

[0012] Furthermore, the power loads in the three load branches can be removed as needed, but at least one load branch must still have a power load connected to it.

[0013] Furthermore, the controllable load unit also includes a switch drive module, one end of which is connected to the control unit and the other end is connected to the control switches of all load branches, for uniformly controlling the on and off of all control switches according to the instructions of the control unit.

[0014] Furthermore, the voltage sampling circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, and an amplifier;

[0015] The first resistor and the second resistor are connected in series. One end is connected to the non-inverting input terminal of the amplifier, and the other end is connected to the AC output terminal of any phase of the inverter.

[0016] The third and fourth resistors are connected in series, with one end connected to the inverting input terminal of the amplifier and the other end connected to the neutral output terminal of the inverter.

[0017] The connection between the first resistor and the second resistor is connected between the reference voltage and the signal ground via a fifth resistor;

[0018] The amplifier's inverting input and output are connected via a sixth resistor, and the amplifier's output is connected to a control unit.

[0019] Furthermore, the control switch is a relay or a contactor.

[0020] Furthermore, the control unit is a DSP.

[0021] This utility model also provides an inverter, including the inverter wiring detection circuit described above.

[0022] The beneficial effects of this utility model are:

[0023] 1. Proactive prevention and intelligent diagnosis: This utility model integrates a detection circuit inside the inverter, which can perform wiring status diagnosis after installation and before formal power-on operation, proactively discover problems, eliminate faults in their infancy, and avoid the trouble of passive troubleshooting afterward.

[0024] 2. Reliable detection and ingenious principle: Based on the electrical principle that the load voltage will change abnormally when the live wire or neutral wire is missing in a three-phase four-wire system, the connection of a controllable load and voltage detection can accurately and effectively determine whether the connection is reliable with a low false alarm rate.

[0025] 3. Low cost and easy integration: The detection circuit is mainly composed of common and low-cost hardware circuits such as relays (or contactors), power loads and voltage detection units. It does not require complex and expensive additional equipment and is easy to integrate into existing inverter products with almost no increase in hardware costs.

[0026] 4. Enhance user experience and security: This feature can greatly simplify the on-site installation and commissioning process, reduce reliance on the technical skills of installers, effectively prevent equipment failures caused by installation errors, improve product reliability and user satisfaction, and enhance the overall security of the system. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the inverter wiring detection circuit connection in an embodiment of this utility model.

[0028] Figure 2 This is a schematic diagram of the controllable load unit circuit connection (three-phase resistive load) according to an embodiment of the present invention.

[0029] Figure 3 This is a schematic diagram of the circuit connection of the controllable load unit (three-phase capacitive load) according to an embodiment of this utility model.

[0030] Figure 4 This is a schematic diagram of the controllable load unit circuit connection (three-phase inductive load) according to an embodiment of the present invention.

[0031] Figure 5 This is a schematic diagram of the circuit connection of the controllable load unit (three-phase hybrid load) according to an embodiment of the present invention.

[0032] Figure 6 This is a schematic diagram of the controllable load unit circuit connection in an embodiment of the present invention (only one phase power load).

[0033] Figure 7 This is a schematic diagram of the controllable load unit circuit connection in an embodiment of the present invention (only two-phase power load).

[0034] Figure 8 This is a schematic diagram of the voltage sampling circuit connection in an embodiment of the present invention. Detailed Implementation

[0035] The utility model will be further explained and described below with reference to the accompanying drawings and embodiments.

[0036] like Figure 1 As shown, this utility model provides an inverter wiring detection circuit, including: a controllable load unit, a voltage detection unit, and a control unit.

[0037] The controllable load unit includes three load branches consisting of control switches and power loads connected in series, connected between the AC output terminal of any phase of the inverter and the neutral output terminal. The voltage detection unit includes three voltage sampling circuits, each connected in parallel with its corresponding load branch, for real-time detection of the load branch voltage. The controllable load unit also includes a switch drive module, one end connected to the control unit and the other end connected to the control switches of all load branches, for unified control of the on / off state of all control switches according to the instructions of the control unit.

[0038] The controllable load unit includes three load branches consisting of a control switch and a power load connected in series, which are connected between any one phase AC output terminal (L1 phase, L2 phase, L3 phase) of the inverter and the neutral output terminal.

[0039] The power loads in all load branches include the following forms:

[0040] All are resistive loads and their resistance values ​​are not exactly the same, as shown in the attached figure. Figure 2 As shown.

[0041] All are capacitive loads and their capacitance values ​​are not exactly the same, as shown in the attached figure. Figure 3 As shown.

[0042] All are inductive loads and their inductance values ​​are not exactly the same, as shown in the attached figure. Figure 4 As shown.

[0043] For a mixed load, with a random combination of resistive, capacitive, and inductive properties, one implementation is as follows: Figure 5 As shown.

[0044] The power loads in the three load branches can be removed as needed, but at least one load branch must still have a power load connected to it. For example... Figure 6 , Figure 7 As shown.

[0045] The control switch is a relay or a contactor.

[0046] The voltage detection unit includes three voltage sampling circuits, which are connected in parallel with the corresponding load branches to detect the voltage of the load branches in real time, that is, to detect the phase voltage of the three-phase output terminals of L1, L2 and L3 relative to the neutral line N.

[0047] like Figure 8As shown, the voltage sampling circuit includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, and an amplifier. The first resistor R1 and the second resistor R2 are connected in series, with one end connected to the non-inverting input of the amplifier and the other end connected to the AC output of any phase of the inverter. The third resistor R3 and the fourth resistor R4 are connected in series, with one end connected to the inverting input of the amplifier and the other end connected to the neutral output of the inverter. The connection between the first and second resistors is connected between the reference voltage V_REF and the signal ground SGND via the fifth resistor R5. The inverting input and output of the amplifier are connected via the sixth resistor R6, and the output of the amplifier is connected to the control unit.

[0048] The control unit connects the controllable load unit and the voltage detection unit, and is used to control the on and off of the control switch in the controllable load unit and to receive voltage sampling data obtained from the voltage detection unit.

[0049] The control unit can be a DSP.

[0050] The working principle of the inverter wiring detection circuit is as follows:

[0051] After the inverter is installed, the control unit (DSP) first disconnects the control switch to ensure the load unit is not connected to the circuit. Then, it closes the control switch to connect the power load between the live wires L1 / L2 / L3 and the neutral wire N. At the moment the load is connected or after a short delay, the voltage detection unit samples the phase voltage of each phase. It then determines whether a phase wire is missing based on the established criteria. If the connection is reliable, the DSP can disconnect the test load and allow the inverter to enter the normal startup procedure. If the live or neutral wire is not connected or has poor contact, the circuit loop cannot be established properly, and the inverter startup will be immediately locked, requiring inspection by the installer.

[0052] This utility model also provides an inverter, including the inverter wiring detection circuit described above.

[0053] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. An inverter wiring detection circuit, characterized by comprising: The application relates to an inverter wiring detection circuit. The controllable load unit comprises three load branches composed of control switches and power loads in series, and is connected between any phase AC output end and zero line output end of the inverter. The voltage detection unit comprises three voltage sampling loops in parallel with the corresponding load branches, and is used for real-time detection of the voltage of the load branches. The control unit is connected with the controllable load unit and the voltage detection unit, and is used for controlling the on and off of the control switches in the controllable load unit and receiving the voltage sampling data obtained by the voltage detection unit. The power loads in the three load branches comprise the following forms: resistive load, capacitive load, inductive load or mixed load; the mixed load is a random combination of resistive load, capacitive load and inductive load.

2. The inverter wiring detection circuit according to claim 1, characterized by, The power loads in the three load branches can be removed according to needs, but at least one load branch is connected with the power load.

3. The inverter wiring detection circuit of claim 1, wherein: The controllable load unit further comprises a switch driving module, one end of which is connected with the control unit, and the other end of which is connected with the control switches of all the load branches, and the switch driving module is used for uniformly controlling the on and off of all the control switches according to the instruction of the control unit.

4. The inverter wiring detection circuit of claim 1, wherein: The voltage sampling loop comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and an amplifier.

5. The inverter wiring detection circuit of claim 1, wherein: The first resistor and the second resistor are connected in series, one end of which is connected with the same direction input end of the amplifier, and the other end of which is connected with any phase AC output end of the inverter. The third resistor and the fourth resistor are connected in series, one end of which is connected with the reverse input end of the amplifier, and the other end of which is connected with the zero line output end of the inverter. The connection position of the first resistor and the second resistor is connected with the reference voltage and the signal ground through the fifth resistor. The reverse input end and the output end of the amplifier are connected through the sixth resistor, and the output end of the amplifier is connected with the control unit. The control switch is a relay or a contactor.

6. The inverter wiring detection circuit of claim 1, wherein: The control unit is a DSP.

7. The inverter wiring detection circuit of claim 1, wherein: The application further discloses an inverter wiring detection circuit comprising the inverter wiring detection circuit of any one of claims 1-7.

8. An inverter, characterized by: ​

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