Grounding detection method and device for inverter, storage medium and electronic terminal

Abstract

The application discloses a ground wire detection method and device for an inverter, a storage medium and an electronic terminal. When R-phase, S-phase, T-phase and zero-line connection terminals of the inverter are electrically connected to a three-phase power grid and the three-phase power grid is operated in an unbalanced manner, a difference between voltages between the zero-line connection terminal and a ground wire PE is detected. If the difference is greater than a first threshold value, the connection between the shell and the ground wire PE is abnormal. When the three-phase power grid is operated in a balanced manner, the R-phase, S-phase, T-phase and zero-line connection terminals are all disconnected from the three-phase power grid by controlling a switching device, and then the inverter R-phase, S-phase, T-phase and zero-line connection terminals output three-phase power of a preset specification, and a difference between voltages between the zero-line of the three-phase power grid and the ground wire of the inverter is detected. If the difference is greater than a second threshold value, the connection between the shell and the ground wire PE is abnormal, so that whether the ground wire is detached can be detected.

Description

Technical Field

[0001] This invention relates to the field of inverter connection detection technology, and more specifically, to a method, apparatus, storage medium, and electronic terminal for detecting the ground wire of an inverter. Background Technology

[0002] An inverter is a power electronic device used to convert direct current (DC) electrical energy into alternating current (AC) electrical energy. It plays a crucial role in renewable energy generation systems, such as solar photovoltaic (PV) systems and wind power systems. Inverters convert DC electricity generated by photovoltaic cells or wind turbines into AC electricity to meet the power needs of residential, industrial, and commercial applications.

[0003] In the design and use of inverters, the quality of the grounding connection is crucial to their performance and safety. Inverters are typically connected to a three-phase power grid via three-phase wires to provide power transmission and maintain grid stability. However, a poor grounding connection can lead to problems such as an electrified inverter casing, current leakage, arcing, and electrical fires, potentially causing equipment damage, personal injury, or even grid failure in severe cases. Therefore, it is understandable that checking the inverter's grounding connection is essential.

[0004] Currently, there are some traditional methods for testing ground connections, such as using resistance measurement, voltage measurement, or thermal imaging to assess the quality of ground connections. However, these methods have limitations, such as complex testing procedures and the inability to be performed in real-time environments. Therefore, finding ways to address these shortcomings and deficiencies through technological solutions is a key area of ​​focus for those working in this industry. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems by providing a grounding detection method for an inverter. The inverter is provided with an R-phase terminal, an S-phase terminal, a T-phase terminal, and a neutral terminal. These terminals are used for electrical connection to a three-phase power grid. The inverter also includes a ground wire (PE) for electrical connection to its casing. The inverter is equipped with a switching device capable of electrically connecting any one of the R-phase, S-phase, T-phase, and neutral terminals to the three-phase power grid; the switching device is also capable of disconnecting any one of these terminals from the three-phase power grid. Specifically, the method includes the following steps:

[0006] When the inverter's R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced, the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE is detected; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal.

[0007] When the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, the switching device is first controlled to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid. Then, the inverter's R-phase, S-phase, T-phase, and neutral terminals output three-phase power of a preset specification. The voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire is detected. If NPEvaltRms2 is greater than a second threshold, the connection between the casing and the ground wire PE is abnormal.

[0008] Including any of the above technical solutions, it also includes the following steps: if the NPE VoltRms1 is less than the first threshold, then the connection between the outer shell and the ground wire PE is normal.

[0009] Including any of the above technical solutions, it also includes the following steps: if the NPEvaltRms2 is less than the second threshold, then the connection between the outer shell and the ground wire PE is normal.

[0010] Including any of the above technical solutions, specifically including: the first threshold is 40V.

[0011] Including any of the above technical solutions, specifically including: the second threshold is 40V.

[0012] Including any of the above technical solutions, it also includes: the effective value of the R phase, S phase and T phase in the three-phase power grid is 230V.

[0013] Including any of the above technical solutions, specifically including: the switching device is a gate relay.

[0014] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides a ground wire detection device for an inverter. The inverter is provided with an R-phase terminal, an S-phase terminal, a T-phase terminal, and a neutral wire terminal. The R-phase terminal, S-phase terminal, T-phase terminal, and neutral wire terminal are used for electrical connection with a three-phase power grid. The inverter is also provided with a ground wire PE for electrical connection with the casing.

[0015] The inverter is equipped with a switching device that can electrically connect any one of the R-phase, S-phase, T-phase, and neutral terminals to the three-phase power grid; the switching device can also disconnect any one of the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid, and includes the following modules:

[0016] The first processing module is used to detect the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE when the inverter's R-phase terminal, S-phase terminal, T-phase terminal and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal.

[0017] The second processing module is used to, when the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, first control the switching device to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid, and then control the inverter's R-phase, S-phase, T-phase, and neutral terminals to output three-phase power of a preset specification; detect the voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire; if NPEvaltRms2 is greater than a second threshold, the connection between the casing and the ground wire PE is abnormal.

[0018] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides a storage medium storing program instructions, which, when executed, implement the ground detection method for an inverter as described in any of the above claims.

[0019] To achieve one of the above-mentioned objectives, one embodiment of the present invention provides an electronic terminal, including a processor and a memory, wherein the memory stores program instructions, and the processor executes the program instructions to implement the ground detection method for an inverter as described in any of the above claims.

[0020] The advantages provided by this invention are: it can monitor the grounding connection of the inverter in real time, ensuring the safety of the inverter and improving detection efficiency. Attached Figure Description

[0021] Figure 1 This is a schematic flowchart of the ground wire detection method for inverters described in this invention;

[0022] Figure 2 This is a schematic flowchart of the ground wire detection method for inverters described in this invention;

[0023] Figure 3 This is a schematic diagram of the ground wire detection device for inverters described in this invention. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present invention, and any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the scope of protection of the present invention.

[0025] If the present invention involves orientation (e.g., up, down, left, right, front, back, outside, inside, etc.) in its description, then the orientations involved need to be defined.

[0026] The scope of embodiments described herein includes the entire scope of the claims and all available equivalents thereof. Throughout this document, the terms “first,” “second,” etc., are used only to distinguish one element from another without requiring or implying any actual relationship or order between the elements. Indeed, a first element can also be referred to as a second element, and vice versa. Furthermore, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a structure, apparatus, or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a structure, apparatus, or device. Without further limitation, an element defined by the phrase “comprising one…” does not exclude the presence of other identical elements in the structure, apparatus, or device that includes said element.

[0027] Embodiment 1 of the present invention provides a ground wire detection method for an inverter. The inverter is provided with an R-phase terminal, an S-phase terminal, a T-phase terminal, and a neutral terminal. The R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal are used for electrical connection with a three-phase power grid. The inverter is also provided with a ground wire PE for electrical connection with the casing.

[0028] like Figure 3 As shown, the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal are three ports that can be electrically connected to the corresponding phases in the three-phase power grid.

[0029] like Figure 1As shown, when the system detects that the voltage, current, or power in the three-phase power supply or load of the inverter are not equal or do not have a phase difference of 120 degrees, it detects the voltage difference NPEvalt Rms1 between the neutral wire terminal and the ground wire PE; if NPEvalt Rms1 is greater than 40V, the connection between the casing and the ground wire PE is abnormal; if NPEvalt Rms1 is less than 40V, the connection between the casing and the ground wire PE is normal.

[0030] like Figure 2 As shown, when the system detects that the voltage, current, or power in the three-phase power supply or load of the inverter are completely equal and the phase difference is 120 degrees, it controls the switching device to disconnect the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal from the three-phase power grid. Then, it controls the inverter to output three-phase power of a preset specification at the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal. Here, the preset specification of three-phase power is that the effective values ​​of R-phase, S-phase, and T-phase are 230V, 0V, and 0V, respectively. The system detects the voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter ground wire. If NPEvaltRms2 is greater than 40V, the connection between the casing and the ground wire PE is abnormal; if NPEvaltRms2 is less than 40V, the connection between the casing and the ground wire PE is normal.

[0031] In practice, safety capacitors are typically installed between the ground wire and the three-phase wires or between the ground wire and the neutral wire. These safety capacitors are devices used to improve the power factor of a power system. The power factor is the ratio of active power to apparent power in an AC circuit; it reflects the circuit's ability to effectively utilize electrical energy. An ideal power factor of 1 indicates that there is no ineffective power in the circuit.

[0032] Safety capacitors help improve the power factor of a system by compensating for reactive power in the circuit. When the power factor of a system is low, there is a phase difference between current and voltage, which leads to the generation of ineffective power. By connecting safety capacitors, appropriate reactive power can be introduced, making the power factor closer to 1, thereby improving the efficiency and energy utilization of the power grid, reducing the grid load, and improving grid efficiency.

[0033] In a three-phase power grid, the R-phase, S-phase, and T-phase lines are all used to transmit electrical energy; the neutral wire is the neutral conductor used to provide single-phase power and is usually connected to the neutral point of the three-phase power grid; the ground wire guides unwanted current or fault current to the ground to protect people and equipment from electric shock and overcurrent hazards. The ground wire is typically connected to the ground via a grounding electrode or grounding conductor and is connected to the equipment's grounding system. It is understandable that if the ground wire of an inverter connected to a three-phase power grid is not properly connected, it can lead to problems such as an electrified inverter casing, current leakage, arcing faults, and electrical fires. In severe cases, it may cause equipment damage, personal injury, or even power grid failure. Therefore, checking the inverter's ground wire connection is crucial.

[0034] The inverter is equipped with a switching device that can electrically connect any one of the R-phase, S-phase, T-phase, and neutral terminals to the three-phase power grid; the switching device can also disconnect any one of the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid, specifically including the following steps:

[0035] When the inverter's R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced, the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE is detected; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal.

[0036] Here, three-phase unbalanced operation refers to a situation where the voltage, current, or power in the three-phase power supply or load is not equal or does not have a phase difference of 120 degrees. Three-phase imbalance can lead to problems such as voltage fluctuations, current imbalance, increased power loss, and equipment overload. If the imbalance is severe or persists for an extended period, it may cause equipment damage, power system instability, and other electrical problems.

[0037] When the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, the switching device is first controlled to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid. Then, the inverter's R-phase, S-phase, T-phase, and neutral terminals output three-phase power of a preset specification. The voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire is detected. If NPEvaltRms2 is greater than the second threshold, the connection between the casing and the ground wire PE is abnormal.

[0038] Here, three-phase balanced operation refers to a state in which the voltage, current, or power in the three-phase power supply or load are completely equal and the phase difference is 120 degrees. Under three-phase balanced conditions, the voltage amplitude and current amplitude of each phase are equal, the power system operates stably, the load is balanced, the power transmission is uniform, and the load distribution among the three-phase power supplies is uniform.

[0039] In this embodiment, the following step is also included: if NPE VoltRms1 is less than the first threshold, then the connection between the outer shell and the ground wire PE is normal.

[0040] In this embodiment, the following step is also included: if the NPE VoltRms2 is less than the second threshold, then the connection between the outer casing and the ground wire PE is normal.

[0041] In this embodiment, the first threshold is 40V.

[0042] In this embodiment, the second threshold is specifically 40V.

[0043] In this embodiment, the effective values ​​of the R-phase, S-phase, and T-phase in the three-phase power grid are 230V.

[0044] In this embodiment, the switching device is a gate relay.

[0045] Here, a gate relay is an electronic switching device used to control circuits with high voltage and high current. Its main components include an input terminal, an output terminal, and a control circuit. The input terminal is typically connected to a low-voltage control signal, such as the output of a microprocessor, logic gate, or sensor. The control circuit receives the input signal and controls the relay's switching state at the output terminal based on the signal's state. The gate relay operates by controlling the relay's switching state at the output terminal through the operation of the control circuit. When a control signal is input, the control circuit applies an appropriate voltage or current to the output terminal, thereby changing the relay's switching state. This change can connect or disconnect the circuit to control the load power supply or signal.

[0046] Embodiment 2 of the present invention provides a ground wire detection device for an inverter. The inverter is provided with an R-phase terminal, an S-phase terminal, a T-phase terminal and a neutral wire terminal. The R-phase terminal, S-phase terminal, T-phase terminal and neutral wire terminal are used for electrical connection with a three-phase power grid. The inverter is also provided with a ground wire PE for electrical connection with the casing.

[0047] The inverter is equipped with a switching device that can electrically connect any one of the R-phase, S-phase, T-phase, and neutral terminals to the three-phase power grid; the switching device can also disconnect any one of the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid; specifically, it includes the following modules:

[0048] The first processing module is used to detect the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE when the inverter's R-phase terminal, S-phase terminal, T-phase terminal and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal.

[0049] The second processing module is used to, when the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, first control the switching device to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid, and then control the inverter's R-phase, S-phase, T-phase, and neutral terminals to output three-phase power of a preset specification; detect the voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire; if NPEvaltRms2 is greater than the second threshold, the connection between the casing and the ground wire PE is abnormal.

[0050] Embodiment 3 of the present invention provides a storage medium storing program instructions, specifically including, when the program instructions are executed, implementing the ground wire detection method for inverters as described above.

[0051] Embodiment 4 of the present invention provides an electronic terminal, including a processor and a memory. The memory stores program instructions, and the processor executes the program instructions to implement the ground wire detection method for an inverter as described above.

[0052] This invention can be a system, method, and / or computer program product. A computer program product may include a readable storage medium having computer-readable program instructions loaded thereon for causing a processor to implement various aspects of the invention.

[0053] A readable storage medium can be a tangible device that holds and stores instructions for use by an instruction execution device. Readable storage media can include, for example, but not limited to, electrical storage devices, magnetic storage devices, optical storage devices, electromagnetic storage devices, semiconductor storage devices, or any suitable combination thereof. More specific examples (a non-exhaustive list) of readable storage media include: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), static random access memory (SRAM), portable compact disc read-only memory (CD-ROM), digital multifunction disc (DVD), memory sticks, floppy disks, mechanical encoding devices, such as punch cards or recessed protrusions storing instructions thereon, and any suitable combination thereof.

[0054] The embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles of the embodiments, their practical application, or technological improvements in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A ground wire detection method for an inverter, wherein the inverter is provided with an R-phase terminal, an S-phase terminal, a T-phase terminal, and a neutral terminal, the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal being used for electrical connection to a three-phase power grid, and the inverter is further provided with a ground wire PE for electrical connection to the casing; the inverter is provided with a switching device, the switching device being capable of electrically connecting any one of the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal to the three-phase power grid; the switching device is also capable of disconnecting any one of the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal from the three-phase power grid; characterized in that, Includes the following steps: When the inverter's R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced, the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE is detected; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal. When the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, the switching device is first controlled to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid. Then, the inverter's R-phase, S-phase, T-phase, and neutral terminals output three-phase power of a preset specification. The voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire PE is detected. If NPEvaltRms2 is greater than a second threshold, the connection between the casing and the ground wire PE is abnormal.

2. The ground wire detection method for an inverter according to claim 1, characterized in that, If NPE VoltRms1 is less than the first threshold, then the connection between the outer casing and the ground wire PE is normal.

3. The grounding detection method for an inverter according to claim 1, characterized in that, If NPE VoltRms2 is less than the second threshold, then the connection between the outer casing and the ground wire PE is normal.

4. The ground wire detection method for an inverter according to claim 1, characterized in that, The first threshold is 40V.

5. The grounding detection method for an inverter according to claim 1, characterized in that, The second threshold is 40V.

6. The ground wire detection method for an inverter according to claim 1, characterized in that, The preset three-phase electrical specifications are that the effective values ​​of the R phase, S phase, and T phase are 230V, 0V, and 0V, respectively.

7. The grounding detection method for an inverter according to claim 1, characterized in that, The switching device is a gate relay.

8. A grounding detection device for an inverter, the inverter being provided with an R-phase terminal, an S-phase terminal, a T-phase terminal, and a neutral terminal, the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal being used for electrical connection to a three-phase power grid, the inverter also being provided with a grounding wire PE for electrical connection to the casing; the inverter being provided with a switching device, the switching device being capable of electrically connecting any one of the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal to the three-phase power grid; the switching device being also capable of disconnecting any one of the R-phase terminal, S-phase terminal, T-phase terminal, and neutral terminal from the three-phase power grid; characterized in that, Includes the following modules: The first processing module is used to detect the voltage difference NPEvaltRms1 between the neutral terminal and the ground wire PE when the inverter's R-phase terminal, S-phase terminal, T-phase terminal and neutral terminal are all electrically connected to the three-phase power grid and the three-phase operation is unbalanced; if NPEvaltRms1 is greater than a first threshold, the connection between the casing and the ground wire PE is abnormal. The second processing module is used to, when the inverter's R-phase, S-phase, T-phase, and neutral terminals are all electrically connected to the three-phase power grid and the three phases are operating in a balanced manner, first control the switching device to disconnect the R-phase, S-phase, T-phase, and neutral terminals from the three-phase power grid, and then control the inverter's R-phase, S-phase, T-phase, and neutral terminals to output three-phase power of a preset specification; detect the voltage difference NPEvaltRms2 between the neutral wire in the three-phase power grid and the inverter's ground wire PE; if NPEvaltRms2 is greater than a second threshold, the connection between the casing and the ground wire PE is abnormal.

9. A storage medium storing program instructions, characterized in that, When the program instructions are executed, they implement the ground detection method for an inverter as described in any one of claims 1 to 7.

10. An electronic terminal, comprising a processor and a memory, wherein the memory stores program instructions, characterized in that, The processor executes program instructions to implement the ground detection method for an inverter as described in any one of claims 1 to 7.

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