Adaptive wiring identification method and system of inverter

Abstract

The invention belongs to the field of inverters, and discloses a self-adaptive wiring identification method and system for an inverter, and the method comprises the steps: obtaining the phase voltage of the inverter in a pre-charging process; determining a first zero-sequence component according to the phase voltage of the inverter in the pre-charging process; the phase voltage of the inverter after pre-charging is completed is obtained; determining a second zero-sequence component according to the phase voltage of the inverter after pre-charging is completed; determining a component difference value according to the first zero-sequence component and the second zero-sequence component; and determining the wiring mode of the inverter based on the component difference value. According to the method, no complex detection algorithm exists, the wiring mode of the inverter can be distinguished according to detection and comparison of the three-phase phase voltage zero-sequence components before and after pre-charging, and the identification method is simple and convenient; and for the normal working process of the inverter, the method does not take out a special period of time for detection in the process, but adds simple judgment in the normal process, so that the inverter is ensured not to be influenced by the identification method.

Description

Technical Field

[0001] The present invention belongs to the field of inverters, and particularly relates to an adaptive wiring recognition method and system for an inverter. Background Art

[0002] The three-wire system and four-wire system of an inverter refer to the ways it connects to the power grid, and the main difference lies in whether it includes the neutral wire (N). Correctly identifying these two wiring methods is crucial for ensuring the safe operation and optimal performance of the inverter.

[0003] In the prior art, high-precision voltage and current sensors are integrated inside the inverter to monitor the electrical parameters of each terminal in real time. However, this will increase the hardware cost.

[0004] The software detection method is as follows: The program will attempt to load different configuration files and record the system behavior (such as power output, frequency, etc.) after each loading. By judging these electrical parameters, the determination of the wiring method is achieved. However, this will increase the software complexity. Summary of the Invention

[0005] The purpose of the present invention is to provide an adaptive wiring recognition method and system for an inverter, so as to solve the problem that in the prior art, the determination of the wiring method is achieved by judging these electrical parameters, but this will increase the software complexity.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions: In the first aspect, the present invention provides an adaptive wiring recognition method for an inverter, and the method includes: Obtain the phase voltage of the inverter during the pre-charge process; Determine the first zero-sequence component according to the phase voltage of the inverter during the pre-charge process; Obtain the phase voltage of the inverter after the pre-charge is completed; Determine the second zero-sequence component according to the phase voltage of the inverter after the pre-charge is completed; Determine the component difference according to the first zero-sequence component and the second zero-sequence component; Based on the component difference, determine the wiring method of the inverter, and the wiring method of the inverter includes a three-wire system or a four-wire system.

[0007] Preferably, the calculation expression of the first zero-sequence component is: ; In the formula, is the first zero-sequence component, is the phase voltage of phase A of the inverter during the pre-charge process, is the phase voltage of phase B of the inverter during the pre-charge process, is the phase voltage of phase C of the inverter during the pre-charge process.

[0008] Preferably, the calculation expression of the second zero-sequence component is as follows: ; In the formula, is the second zero-sequence component, is the phase-A voltage of the inverter after pre-charging is completed, is the phase-B voltage of the inverter after pre-charging is completed, is the phase-C voltage of the inverter after pre-charging is completed.

[0009] Preferably, the calculation expression of the component difference is as follows: ; In the formula, is the component difference, is the first zero-sequence component, is the second zero-sequence component.

[0010] Preferably, based on the component difference, determining the wiring method of the inverter includes: Judging whether the component difference is greater than a preset component threshold; If so, the wiring method of the inverter is three-wire system; if not, the wiring method of the inverter is four-wire system.

[0011] Preferably, the preset component threshold is 50V.

[0012] In a second aspect, the present invention provides an adaptive wiring recognition system for an inverter, and the system includes: A processor, A pre-charging module, the controlled end of the pre-charging module is connected to the control output end of the processor, and the pre-charging module is used to pre-charge the inverter; A voltage acquisition module, the output end of the voltage acquisition module is electrically connected to the signal input end of the processor, and the voltage acquisition module is used to acquire the phase voltages during the pre-charging process and after the pre-charging is completed of the inverter, and upload the phase voltages during the pre-charging process and after the pre-charging is completed to the processor; The processor is used to implement the above-mentioned adaptive wiring recognition method for the inverter.

[0013] Preferably, the pre-charging module includes: a first pre-charging relay, a second pre-charging relay, a main positive relay, a main negative relay, a pre-charging power supply, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and a second capacitor; The first pre-charge relay includes: a first switch coil and a first normally open contact; the second pre-charge relay includes: a second switch coil and a second normally open contact; the main positive relay includes: a third switch coil and a third normally open contact, and the main negative relay includes: a fourth switch coil and a fourth normally open contact; The first switch coil of the first pre-charge relay, the second switch coil of the second pre-charge relay, the third switch coil of the main positive relay, and the fourth switch coil of the main negative relay are all electrically connected to the control output terminal of the processor; The first end of the first normally open contact of the first pre-charge relay and the first end of the third normally open contact of the main positive relay are both electrically connected to the positive pole of the pre-charge power supply. The second end of the first normally open contact of the first pre-charge relay is electrically connected to the first end of the first resistor. The second end of the first resistor is respectively electrically connected to the second end of the third normally open contact of the main positive relay, the first end of the first capacitor, the first end of the second resistor, and the positive input side of the inverter; The first end of the second normally open contact of the second pre-charge relay and the first end of the fourth switch contact of the main negative relay are both electrically connected to the negative pole of the pre-charge power supply. The second end of the second normally open contact of the second pre-charge relay is electrically connected to the first end of the fourth resistor. The second end of the fourth resistor is respectively electrically connected to the second end of the fourth switch contact of the main negative relay, the first end of the second capacitor, the first end of the third resistor, and the negative input side of the inverter; The center point of the input side of the inverter, the second end of the second resistor, the second end of the third resistor, the second end of the first capacitor, and the second end of the second capacitor are all grounded.

[0014] Preferably, the system further includes: a display module. The communication interface of the display module is electrically connected to the communication interface of the processor, and the display module is used for visually displaying the wiring mode of the inverter.

[0015] Advantageous effects: 1. The present invention does not have a complex detection algorithm. By detecting and comparing the zero-sequence components of the three-phase line voltages before and after pre-charging, the wiring mode of the inverter can be identified, and the identification method is simple and convenient; 2. During the normal operation process of the inverter, the present invention does not specifically set aside a period of time for detection, but adds a simple judgment during the normal process, ensuring that the inverter will not be affected by this identification method. Description of the Drawings

[0016] The drawings are used to provide a further understanding of the embodiments of the present invention, and constitute a part of the specification. They are used together with the following specific embodiments to explain the embodiments of the present invention, but do not constitute a limitation to the embodiments of the present invention. In the drawings: Figure 1It is a flowchart of the adaptive wiring recognition method of an inverter provided by an embodiment of the present invention; Figure 2 It is a block diagram of the adaptive wiring recognition system of an inverter provided by an embodiment of the present invention; Figure 3 It is a circuit diagram of the pre-charge module of an inverter provided by an embodiment of the present invention.

[0017] Explanation of reference numerals: T1, the first pre-charge relay; T2, the second pre-charge relay; T3, the main positive relay; T4, the main negative relay; BAT, the pre-charge power supply; R1, the first resistor; R2, the second resistor; R3, the third resistor; R4, the fourth resistor; C1, the first capacitor; C2, the second capacitor; K1, the first normally open contact; K2, the second normally open contact; K3, the third normally open contact; K4, the fourth switch contact. Specific embodiments

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the present invention in combination with the drawings and the description of the embodiments or the prior art. Obviously, the following description of the drawings is only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention.

[0019] Embodiment 1 Figure 1 It is a flowchart of the adaptive wiring recognition method of an inverter provided by an embodiment of the present invention. As Figure 1 shown, this embodiment provides an adaptive wiring recognition method for an inverter, and the method includes: Step S10: Obtain the phase voltage of the inverter during the pre-charge process; in this embodiment, the inverter is pre-charged, and the output side of the inverter is voltage-collected during the pre-charge process, and the phase voltages of the three phases output by the inverter can be obtained, that is, the A-phase voltage, the B-phase voltage, and the C-phase voltage; in this embodiment, the phase voltages of the three phases of the inverter can be collected by a voltage transformer, and the voltage transformer converts the high voltage into a low voltage according to the electromagnetic induction principle for easy measurement of the phase voltage.

[0020] Step S20: Determine the first zero-sequence component according to the phase voltage of the inverter during the pre-charge process.

[0021] In this embodiment, the calculation expression of the first zero-sequence component is: ; Wherein, is the first zero-sequence component, is the phase A voltage of the inverter during the pre-charging process, is the phase B voltage of the inverter during the pre-charging process, is the phase C voltage of the inverter during the pre-charging process.

[0022] Step S30: Obtain the phase voltage of the inverter after pre-charging is completed; during the pre-charging process, determine whether the inverter has completed pre-charging. If the inverter has completed pre-charging, when pre-charging is completed, collect the phase voltage of the inverter after pre-charging is completed.

[0023] Step S40: Determine the second zero-sequence component according to the phase voltage of the inverter after pre-charging is completed.

[0024] In this embodiment, the calculation expression of the second zero-sequence component is: ; Wherein, is the second zero-sequence component, is the phase A voltage of the inverter after pre-charging is completed, is the phase B voltage of the inverter after pre-charging is completed, is the phase C voltage of the inverter after pre-charging is completed.

[0025] Step S50: Determine the component difference according to the first zero-sequence component and the second zero-sequence component; in this embodiment, subtract the first zero-sequence component from the second zero-sequence component and then take the absolute value to obtain the component difference.

[0026] Therefore, the calculation expression of the component difference in this embodiment is: ; Wherein, is the component difference, is the first zero-sequence component, is the second zero-sequence component.

[0027] Step S60: Determine the wiring mode of the inverter based on the component difference. The wiring mode of the inverter includes three-wire system or four-wire system.

[0028] In this embodiment, the specific steps for determining the wiring mode of the inverter based on the component difference are: Step S601: Determine whether the component difference is greater than a preset component threshold; wherein, the preset component threshold is 50V. In this embodiment, 250V is the intermediate value. Under normal DC input of the inverter, the zero-sequence component of the three-phase three-wire system is 300V, and the component difference of the three-phase four-wire system is within 10V.

[0029] Step S602: If yes, the wiring mode of the inverter is three-wire system; if no, the wiring mode of the inverter is four-wire system.

[0030] Therefore, the present invention does not have a complex detection algorithm. By detecting and comparing the zero-sequence components of the three-phase phase voltages before and after pre-charging, the wiring mode of the inverter can be distinguished, and the identification method is simple and convenient. Moreover, during the normal operation process of the inverter, the present invention does not specifically take out a period of time for detection, but adds a simple judgment during the normal process to ensure that the inverter will not be affected by this identification method.

[0031] Embodiment 2 Figure 2 is a block diagram of an adaptive wiring identification system for an inverter provided by an embodiment of the present invention. As Figure 2 shown, this embodiment provides an adaptive wiring identification system for an inverter. The system includes: a processor, a pre-charging module, and a voltage acquisition module. Among them, the processor is used to implement the adaptive wiring identification method of the inverter in Embodiment 1.

[0032] In this embodiment, the controlled end of the pre-charging module is connected to the control output end of the processor. The pre-charging module is used to pre-charge the inverter. In this embodiment, a pre-charging control instruction is generated on the processor. The pre-charging control signal includes a pre-charging start instruction and a pre-charging stop instruction. The pre-charging control instruction is sent to the pre-charging module. After the pre-charging module responds to the pre-charging control instruction, it starts or stops pre-charging the inverter.

[0033] In this embodiment, the output end of the voltage acquisition module is electrically connected to the signal input end of the processor. The voltage acquisition module is used to acquire the phase voltages during the pre-charging process of the inverter and the phase voltages after the pre-charging is completed, and upload the phase voltages during the pre-charging process and the phase voltages after the pre-charging is completed to the processor. In this embodiment, a voltage transformer is preferably used for the voltage acquisition module.

[0034] As a further optimization of this embodiment, as Figure 3 shown, the pre-charging module includes: a first pre-charging relay T1, a second pre-charging relay T2, a main positive relay T3, a main negative relay T4, a pre-charging power supply BAT, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, and a second capacitor C2; The first pre-charging relay T1 includes: a first switch coil and a first normally open contact K1; the second pre-charging relay T2 includes: a second switch coil and a second normally open contact K2; the main positive relay T3 includes: a third switch coil and a third normally open contact K3, and the main negative relay T4 includes: a fourth switch coil and a fourth normally open contact; The first switching coil of the first precharge relay T1, the second switching coil of the second precharge relay T2, the third switching coil of the main positive relay T3, and the fourth switching coil of the main negative relay T4 are all electrically connected to the control output terminal of the processor; The first end of the first normally open contact K1 of the first precharge relay T1 and the first end of the third normally open contact K3 of the main positive relay T3 are both electrically connected to the positive pole of the precharge power supply BAT. The second end of the first normally open contact K1 of the first precharge relay T1 is electrically connected to the first end of the first resistor R1. The second end of the first resistor R1 is respectively electrically connected to the second end of the third normally open contact K3 of the main positive relay T3, the first end of the first capacitor C1, the first end of the second resistor R2, and the positive pole of the input side of the inverter; The first end of the second normally open contact K2 of the second precharge relay T2 and the first end of the fourth switching contact K4 of the main negative relay T4 are both electrically connected to the negative pole of the precharge power supply BAT. The second end of the second normally open contact K2 of the second precharge relay T2 is electrically connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is respectively electrically connected to the second end of the fourth switching contact K4 of the main negative relay T4, the first end of the second capacitor C2, the first end of the third resistor R3, and the negative pole of the input side of the inverter; The center point of the input side of the inverter, the second end of the second resistor R2, the second end of the third resistor R3, the second end of the first capacitor C1, and the second end of the second capacitor C2 are all grounded.

[0035] In this embodiment, since during the precharge process, the voltage on the DC side of the inverter cannot rise too fast and needs a slow rising process, this embodiment deploys the first capacitor C1 and the second capacitor C2 to reduce the voltage rising speed.

[0036] As a further optimization of this embodiment, the system further includes: a display module. The communication interface of the display module is electrically connected to the communication interface of the processor, and the display module is used to visually display the wiring method of the inverter.

[0037] In this embodiment, the display module can adopt a separate display, and the display is communicatively connected to the processor through an interface; or a display screen can be integrated on the circuit of the system, and the wiring method is visually displayed through the display screen.

[0038] The present invention does not have a complex detection algorithm. By comparing the detection of the zero-sequence components of the three-phase phase voltages before and after precharge, the wiring method of the inverter can be distinguished, and the identification method is simple and convenient; and for the normal working process of the inverter, the present invention does not specifically take out a period of time for detection from this process, but adds a simple judgment during the normal process to ensure that the inverter will not be affected by this identification method.

[0039] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0040] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be realized by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for realizing the functions specified in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0041] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. An adaptive wiring identification method for an inverter, characterized in that: The method comprises: Obtain the phase voltage of the inverter during the pre-charging process; Determining a first zero-sequence component according to a phase voltage of the inverter during a precharging process; Obtain the phase voltage of the inverter after precharging is completed; Determining a second zero-sequence component according to a phase voltage of the inverter after precharging is completed; Determine a component difference according to the first zero-sequence component and the second zero-sequence component; Based on the component difference, a connection mode of the inverter is determined, wherein the connection mode of the inverter includes a three-wire system or a four-wire system.

2. The adaptive wiring identification method of the inverter according to claim 1, characterized in that: The calculation expression of the first zero-sequence component is: ； In the formula, is the first zero-sequence component, is the A-phase voltage of the inverter during the pre-charging process, is the B-phase voltage of the inverter during the pre-charging process, It is the C phase voltage of the inverter during the pre-charging process.

3. The adaptive wiring identification method of the inverter according to claim 2, characterized in that: The calculation expression of the second zero-sequence component is: ； In the formula, is the second zero-sequence component, is the A phase voltage of the inverter after precharging is completed, is the B phase voltage of the inverter after precharging is completed, It is the C phase voltage of the inverter after precharging is completed.

4. The adaptive wiring identification method of the inverter according to claim 3, characterized in that: The calculation expression of the component difference is: ； In the formula, is the component difference, is the first zero-sequence component, is the second zero-sequence component.

5. The method for adaptive wiring identification of an inverter according to any one of claims 1 to 4, characterized in that: Based on the component difference, determine the inverter wiring method, including: Determine whether the component difference is greater than a preset component threshold; If yes, the connection mode of the inverter is three-wire system; if no, the connection mode of the inverter is four-wire system.

6. The adaptive wiring identification method of the inverter according to claim 5, characterized in that: The preset component threshold is 50V.

7. An adaptive wiring identification system for an inverter, characterized in that: The system comprises: processor, A pre-charging module, wherein a controlled end of the pre-charging module is connected to a control output end of the processor, and the pre-charging module is used to pre-charge the inverter; A voltage acquisition module, wherein the output end of the voltage acquisition module is electrically connected to the signal input end of the processor, and the voltage acquisition module is used to collect the phase voltage of the inverter during the pre-charging process and the phase voltage after the pre-charging is completed, and upload the phase voltage during the pre-charging process and the phase voltage after the pre-charging is completed to the processor; The processor is used to implement the adaptive wiring identification method for the inverter according to any one of claims 1 to 6.

8. The adaptive wiring identification system for an inverter according to claim 7, characterized in that: The pre-charging module comprises: a first pre-charging relay, a second pre-charging relay, a main positive relay, a main negative relay, a pre-charging source, a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor and a second capacitor; The first pre-charge relay includes: a first switch coil and a first normally open contact; the second pre-charge relay includes: a second switch coil and a second normally open contact; the main positive relay includes: a third switch coil and a third normally open contact, and the main negative relay includes: a fourth switch coil and a fourth normally open contact; The first switch coil of the first pre-charging relay, the second switch coil of the second pre-charging relay, the third switch coil of the main positive relay and the fourth switch coil of the main negative relay are all electrically connected to the control output terminal of the processor; The first end of the first normally open contact of the first pre-charge relay and the first end of the third normally open contact of the main positive relay are both electrically connected to the positive electrode of the pre-charge power source, the second end of the first normally open contact of the first pre-charge relay is electrically connected to the first end of the first resistor, and the second end of the first resistor is electrically connected to the second end of the third normally open contact of the main positive relay, the first end of the first capacitor, the first end of the second resistor, and the positive electrode of the input side of the inverter; The first end of the second normally open contact of the second pre-charging relay and the first end of the fourth switch contact of the main negative relay are both electrically connected to the negative electrode of the pre-charging power source, the second end of the second normally open contact of the second pre-charging relay is electrically connected to the first end of the fourth resistor, and the second end of the fourth resistor is electrically connected to the second end of the fourth switch contact of the main negative relay, the first end of the second capacitor, the first end of the third resistor, and the negative electrode of the input side of the inverter; A center point of the input side of the inverter, a second end of the second resistor, a second end of the third resistor, a second end of the first capacitor and a second end of the second capacitor are all grounded.

9. The adaptive wiring identification system for an inverter according to claim 7, characterized in that: The system further includes: a display module, a communication interface of the display module is electrically connected to the communication interface of the processor, and the display module is used to visually display the wiring mode of the inverter.

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