Method and device for detecting health degree of switching device and power conversion equipment

Abstract

The embodiment of the invention discloses a method and device for detecting the health degree of a switching device and power conversion equipment. The detection method comprises the following steps: pre-charging a bus of a to-be-detected circuit to an initial bus voltage; according to a preset rule, the working state of each switching device in the circuit to be measured is changed, so that the expected output voltage alternately jumps between the first preset voltage and the second preset voltage, and the real-time bus voltage and the real-time output voltage are measured; wherein the preset rule is formulated according to the position of the switching device in the to-be-tested circuit; the preset rule represents the sequence of changing the working states of the switching devices; and judging whether the switching device is abnormal or not based on the real-time bus voltage and the output voltage.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and in particular to a method and device for detecting the health of a switching device and a power conversion device. Background Art

[0002] The inverter circuit is a conversion circuit that converts DC power into AC power. When the AC side is connected to the grid, that is, the AC side is connected to the power supply, it is called an active inverter; when the AC side is directly connected to the load, it is called a passive inverter.

[0003] Inverter circuits are widely used. For example, batteries, dry cells, solar cells, etc. are all DC power sources. When these power sources are needed to supply power to AC loads, inverter circuits are needed to convert DC power into AC power. For example, inverters for AC motor speed control, uninterruptible power supplies, induction heating power supplies and other power electronic devices all have inverter circuits as their core parts.

[0004] The rectifier circuit corresponds to the inverter circuit. The rectifier circuit is a conversion circuit that converts AC power into DC power. The rectifier circuit also has a wide range of applications.

[0005] However, if there is an abnormality in the device in the inverter circuit and the rectifier circuit, the circuit will not operate normally. How to detect the abnormality of the device in a timely and effective manner has become a technical problem that needs to be solved. Summary of the invention

[0006] In view of this, the embodiments of the present application provide a method and apparatus for detecting the health of a switching device, and a power conversion device, which can effectively detect abnormal conditions of the switching device and ensure the normal operation of the circuit.

[0007] The technical solution of the embodiment of the present application is implemented as follows:

[0008] An embodiment of the present application provides a method for detecting the health of a switching device, comprising: precharging a bus of a circuit to be tested to an initial bus voltage; changing the working state of each switching device in the circuit to be tested according to a preset rule, so that the expected output voltage alternately jumps between a first preset voltage and a second preset voltage, and measuring the real-time bus voltage and output voltage; wherein the preset rule is formulated according to the position of the switching device in the circuit to be tested; the preset rule represents the order of changing the working state of each switching device; and judging whether the switching device has an abnormality based on the real-time bus voltage and the output voltage.

[0009] In the above scheme, the working state of each switching device in the circuit to be tested is changed according to the preset rules, including: starting from the initial state, the working state of each switching device in the circuit to be tested is changed according to the preset rules; wherein, in the initial state, each switching device is in a closed state.

[0010] In the above scheme, based on the real-time bus voltage and the output voltage, it is judged whether the switching device in the circuit to be tested has an abnormality, including: if the real-time bus voltage is inconsistent with the initial bus voltage, it is judged that the switching device has an abnormality; and / or, if the real-time output voltage is inconsistent with the expected output voltage, it is judged that the switching device has an abnormality.

[0011] In the above scheme, the preset rules include: positive half-cycle detection for the positive half-cycle circuit, and negative half-cycle detection for the negative half-cycle circuit; based on the real-time bus voltage and the output voltage, judging whether the switching device has an abnormality, including: when the positive half-cycle detection is performed on the circuit to be tested, judging whether the switching device on the positive half-cycle circuit has an abnormality; wherein, in the positive half-cycle detection, the output voltage is greater than or equal to 0; and / or, when the negative half-cycle detection is performed on the circuit to be tested, judging whether the switching device on the negative half-cycle circuit has an abnormality; wherein, in the negative half-cycle detection, the output voltage is less than or equal to 0.

[0012] In the above scheme, the initial bus voltage is determined based on the maximum withstand voltage of each of the switching devices in the circuit to be tested; the second preset voltage is the initial bus voltage, and the expected output voltage is determined based on the initial bus voltage.

[0013] In the above scheme, the circuit to be tested includes: a T-type three-level single-phase inverter circuit; the T-type three-level single-phase inverter circuit includes: a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; wherein the first switch tube and the second switch tube are connected in series; the third switch tube and the fourth switch tube are connected in series; one end of the third switch tube is connected to the connection point of the first switch tube and the second switch tube;

[0014] The positive half-cycle detection includes: closing all switch tubes of the T-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; opening the first switch tube, and measuring the bus voltage and the output voltage; closing the first switch tube, opening the third switch tube, and measuring the bus voltage and the output voltage;

[0015] The negative half-cycle detection includes: closing all switch tubes of the T-type three-level single-phase inverter circuit and measuring the bus voltage and the output voltage; turning on the second switch tube and measuring the bus voltage and the output voltage; closing the first switch tube, turning on the fourth switch tube, and measuring the bus voltage and the output voltage.

[0016] In the above scheme, the circuit to be tested includes: an I-type three-level single-phase inverter circuit; the I-type three-level single-phase inverter circuit includes: a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube connected in series in sequence;

[0017] The positive half-cycle detection includes: closing all the switch tubes of the I-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; opening the fifth switch tube, and measuring the bus voltage and the output voltage; opening the sixth switch tube, and measuring the bus voltage and the output voltage; closing the fifth switch tube, opening the seventh switch tube, and measuring the bus voltage and the output voltage;

[0018] The negative half-cycle detection includes: closing all the switch tubes of the I-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; turning on the eighth switch tube, and measuring the bus voltage and the output voltage; turning on the seventh switch tube, and measuring the bus voltage and the output voltage; closing the eighth switch tube, turning on the sixth switch tube, and measuring the bus voltage and the output voltage.

[0019] An embodiment of the present application also provides a device for detecting the health of a switching device, comprising: a pre-charging module, configured to pre-charge the bus of the circuit to be tested to an initial bus voltage; an adjustment module, configured to change the working state of each switching device in the circuit to be tested according to a preset rule, so that the expected output voltage alternately jumps between a first preset voltage and a second preset voltage; wherein the preset rule is formulated according to the position of the switching device in the circuit to be tested; the preset rule represents the order of changing the working state of each switching device; a measuring module, configured to measure the real-time bus voltage and output voltage; a judgment module, configured to judge whether there is an abnormality in the switching device based on the real-time bus voltage and the output voltage.

[0020] In the above scheme, the judgment module is also configured to judge that there is an abnormality in the switching device if the real-time bus voltage is inconsistent with the initial bus voltage; and / or judge that there is an abnormality in the switching device if the real-time output voltage is inconsistent with the expected output voltage.

[0021] An embodiment of the present application also provides a power conversion device, including a device for detecting the health of a switching device as described in the above scheme.

[0022] It can be seen that the embodiments of the present application provide a method, device and power conversion device for detecting the health of a switching device, which can change the working state of each switching device in the circuit to be tested according to preset rules, and judge whether the switching device is abnormal based on the bus voltage and output voltage measured in real time. Therefore, the switching device can be repaired or replaced in time to ensure the normal operation of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of an optional implementation flow of a method for detecting the health of a switching device provided in an embodiment of the present application;

[0024] Figure 2 A topological structure diagram of a T-type three-level single-phase inverter circuit provided in an embodiment of the present application;

[0025] Figure 3 A topological structure diagram of a type I three-level single-phase inverter circuit provided in an embodiment of the present application;

[0026] Figure 4 A topological structure diagram of a T-type three-level three-phase inverter circuit provided in an embodiment of the present application;

[0027] Figure 5 A schematic diagram of an optional structure of a device for detecting the health of a switching device provided in an embodiment of the present application;

[0028] Figure 6 An optional structural diagram of a power conversion device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application are further elaborated in detail below in conjunction with the drawings and embodiments. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0030] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict. The terms "first / second / third" involved are merely used to distinguish similar objects and do not represent a specific order for the objects. It is understood that "first / second / third" may be interchanged in a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing this application and are not intended to limit this application.

[0032] Figure 1 A schematic diagram of the implementation flow of a method for detecting the health of a switching device provided in an embodiment of the present application is shown in FIG. Figure 1 As shown, the method includes steps S101 to S103.

[0033] S101, pre-charging the bus of the circuit to be tested to an initial bus voltage.

[0034] In the embodiment of the present application, when starting to detect the switch device in the circuit to be tested, the bus of the circuit to be tested needs to be precharged to an initial bus voltage, wherein the initial bus voltage is determined based on the maximum withstand voltage of each switch device in the circuit to be tested.

[0035] In some embodiments of the present application, the second preset voltage is an initial bus voltage, and the expected output voltage is determined according to the initial bus voltage.

[0036] refer to Figure 2 and Figure 3 , bus voltage includes positive bus voltage V bus+ and negative bus voltage V bus- , where the positive bus voltage V bus+ needs to be precharged to a positive voltage, the negative bus voltage V bus- needs to be precharged to a negative voltage. For example, the positive bus voltage V bus+ Precharge to 100V, and the negative bus voltage V bus- Pre-charged to -100V.

[0037] In an embodiment of the present application, before the device is turned on, a smaller voltage can be used to pre-charge the bus of the circuit to be tested in the device, and then the devices of the circuit to be tested can be detected. In this way, the abnormal state of the device can be detected in advance, and the impact on the circuit caused by the abnormal device can be prevented.

[0038] S102, according to a preset rule, changing the working state of each switch device in the circuit to be tested, so that the expected output voltage alternately jumps between a first preset voltage and a second preset voltage, and measuring the real-time bus voltage and output voltage.

[0039] In the embodiment of the present application, the preset rule is formulated according to the position of the switch device in the circuit to be tested. The preset rule represents the order of changing the working state of each switch device; that is, according to the preset rule, the working state of each switch device will be changed in a specific order. In this way, the expected output voltage can alternately jump between the first preset voltage and the second preset voltage while the working state of the switch device changes. In other words, each time the working state of the switch device changes, the expected output voltage can be caused to jump correspondingly.

[0040] In some embodiments of the present application, the first preset voltage may be 0, and the second preset voltage may be a positive initial bus voltage (100V) or a negative initial bus voltage (-100V). Thus, the expected output voltage may jump between 0~100~0, or between 0~-100~0.

[0041] In some embodiments of the present application, starting from an initial state, the working state of each switching device in the circuit to be tested can be changed according to a preset rule; wherein, in the initial state, each switching device is in a closed state.

[0042] In some embodiments of the present application, the preset rules include: positive half-cycle detection for a positive half-cycle circuit, and negative half-cycle detection for a negative half-cycle circuit.

[0043] Among them, the positive half-cycle circuit is the positive bus voltage V bus+ The corresponding current path; in the positive half cycle detection, the output voltage V ac It should be greater than or equal to 0. When the positive half-cycle detection is performed on the circuit to be tested, it can be determined whether there is an abnormality in the switching device on the positive half-cycle circuit.

[0044] Correspondingly, the negative half-cycle circuit is the negative bus voltage V bus- The corresponding current path; in the negative half cycle detection, the output voltage V ac It should be less than or equal to 0. When the negative half-cycle detection is performed on the circuit to be tested, it can be determined whether the switching device on the negative half-cycle circuit is abnormal.

[0045] In some embodiments of the present application, the circuit to be tested includes: a T-type three-level single-phase inverter circuit. Figure 2As shown, the T-type three-level single-phase inverter circuit includes: a first switch tube S11, a second switch tube S12, a third switch tube S13 and a fourth switch tube S14.

[0046] In the present application examples, reference Figure 2 The first switch tube S11 and the second switch tube S12 are connected in series. The third switch tube S13 and the fourth switch tube S14 are connected in series. One end of the third switch tube S13 is connected to the connection point between the first switch tube S11 and the second switch tube S12.

[0047] It should be noted that for Figure 2 The circuit topology shown in FIG. 1 can be tested according to the steps shown in Table 1. Steps 1 to 3 shown in Table 1 are for Figure 2 The positive half-cycle detection of the positive half-cycle circuit in Table 1 is for Figure 2 Negative half-cycle detection of the negative half-cycle circuit.

[0048] Table 1

[0049] step S11 S12 S13 S14 <![CDATA[Expected V ac > 1 closure closure closure closure 0V 2 Activate closure closure closure 100V 3 closure closure Activate closure 0V 4 closure closure closure closure 0V 5 closure Activate closure closure -100V 6 closure closure closure Activate 0V

[0050] In the embodiment of the present application, the following steps 1 to 3 shown in Table 1 can be followed to complete the Figure 2 The positive half-cycle detection of the positive half-cycle circuit in the embodiment of the present invention is shown in step 1. Specifically, in step 1, the first switch tube S11, the second switch tube S12, the third switch tube S13 and the fourth switch tube S14 are all in the off state, and the real-time bus voltage V can be measured. bus+ and V bus- , and the output voltage V ac Then, step 2 can be executed to turn on the first switch tube S11, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 3 can be executed to turn off the first switch tube S11 and turn on the third switch tube S13. At the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac This completes Figure 2 Positive half cycle detection of the circuit.

[0051] Accordingly, you can follow steps 4 to 6 shown in Table 1 to complete Figure 2 The negative half cycle detection of the negative half cycle circuit in the embodiment of the present invention is performed, wherein step 4 shows the initial state of the negative half cycle detection. Specifically, in step 4, the first switch tube S11, the second switch tube S12, the third switch tube S13 and the fourth switch tube S14 are all in the closed state, and the real-time bus voltage Vbus+ and V bus- , and the output voltage V ac Then, step 5 can be executed to turn on the second switch tube S12, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 6 can be executed to turn off the second switch tube S12 and turn on the fourth switch tube S14. At the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac This completes Figure 2 Negative half cycle detection of the circuit.

[0052] It should be noted that, for a T-type three-level single-phase inverter circuit, the positive half-cycle detection and the negative half-cycle detection are relatively independent and can be performed separately or in any order. That is, only steps 1 to 3 shown in Table 1 can be performed; only steps 4 to 6 shown in Table 1 can be performed; steps 1 to 3 shown in Table 1 can be performed first, and then steps 4 to 6 shown in Table 1 can be performed; steps 4 to 6 shown in Table 1 can be performed first, and then steps 1 to 3 shown in Table 1 can be performed. No limitation is made here.

[0053] It should also be noted that, during the detection process, if an abnormality occurs, the detection can be stopped to confirm and eliminate the abnormality. In other words, when executing any step in Table 1, if an abnormality occurs, the other steps in Table 1 can be stopped.

[0054] In some embodiments of the present application, the circuit to be tested includes: an I-type three-level single-phase inverter circuit. Figure 3 As shown, the I-type three-level single-phase inverter circuit includes: a fifth switch tube S21, a sixth switch tube S22, a seventh switch tube S23 and an eighth switch tube S24 which are connected in series in sequence.

[0055] It should be noted that for Figure 3 The circuit topology shown in FIG. 2 can be tested according to the steps shown in Table 2. Among them, steps 1 to 4 shown in Table 2 are for Figure 3 The positive half-cycle detection of the positive half-cycle circuit in Table 2 is for steps 5 to 8. Figure 3 Negative half-cycle detection of the negative half-cycle circuit.

[0056] Table 2

[0057] step S21 S22 S23 S24 <![CDATA[Expected V ac > 1 closure closure closure closure 0V 2 Activate closure closure closure 0V 3 Activate Activate closure closure 100V 4 closure Activate Activate closure 0V 5 closure closure closure closure 0V 6 closure closure closure Activate 0V 7 closure closure Activate Activate -100V 8 closure Activate Activate closure 0V

[0058] In the embodiment of the present application, the following steps 1 to 4 shown in Table 2 can be followed to complete the Figure 3The positive half cycle detection of the positive half cycle circuit in the embodiment of the present invention is performed, wherein step 1 shows the initial state of the positive half cycle detection. Specifically, in step 1, the fifth switch tube S21, the sixth switch tube S22, the seventh switch tube S23 and the eighth switch tube S24 are all in the closed state, and the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 2 can be executed to turn on the fifth switch tube S21, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 3 can be executed to turn on the sixth switch tube S22, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 4 can be executed to turn off the fifth switch tube S21 and turn on the seventh switch tube S23. At the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac This completes Figure 3 Positive half cycle detection of the circuit.

[0059] Accordingly, you can follow steps 5 to 8 shown in Table 2 to complete Figure 3 The negative half cycle detection of the negative half cycle circuit in the embodiment of the present invention is performed, wherein step 5 shows the initial state of the negative half cycle detection. Specifically, in step 5, the fifth switch tube S21, the sixth switch tube S22, the seventh switch tube S23 and the eighth switch tube S24 are all in the closed state, and the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 6 can be executed to turn on the eighth switch tube S24, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 7 can be executed to turn on the seventh switch tube S23, and at the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac Then, step 8 can be executed to turn off the eighth switch tube S24 and turn on the sixth switch tube S22. At the same time, the real-time bus voltage V bus+ and V bus- , and the output voltage V ac This completes Figure 3 Negative half cycle detection of the circuit.

[0060] It should be noted that, for the I-type three-level single-phase inverter circuit, the positive half-cycle detection and the negative half-cycle detection are relatively independent and can be performed separately or in any order. That is, only steps 1 to 4 shown in Table 2 can be performed; only steps 5 to 8 shown in Table 2 can be performed; steps 1 to 4 shown in Table 2 can be performed first, and then steps 5 to 8 shown in Table 2 can be performed; steps 5 to 8 shown in Table 2 can be performed first, and then steps 1 to 4 shown in Table 2 can be performed. No limitation is made here.

[0061] It should also be noted that, during the detection process, if an abnormality occurs, the detection can be stopped to confirm and eliminate the abnormality. In other words, when executing any step in Table 2, if an abnormality occurs, the other steps in Table 2 can be stopped.

[0062] S103: Based on the real-time bus voltage and output voltage, determine whether there is an abnormality in the switch device.

[0063] In some embodiments of the present application, the measured real-time bus voltage can be compared with the initial bus voltage during pre-charging; if the real-time bus voltage is inconsistent with the initial bus voltage, it is determined that there is an abnormality in the switching device.

[0064] In some embodiments of the present application, the measured real-time output voltage may be compared with the expected output voltage; if the real-time output voltage is inconsistent with the expected output voltage, it is determined that an abnormality exists in the switching device.

[0065] It should be noted that Table 3 corresponds to Figure 2 and Table 1. Follow steps 1 to 6 shown in Table 1 to Figure 2 After detecting the circuit topology structure in the circuit, it can be determined whether each switch device is abnormal according to the rules shown in Table 3.

[0066] Table 3

[0067]

[0068] In the embodiment of the present application, if the real-time output voltage V obtained in step 1 of Table 1 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 1 is ac is not 0V; then, referring to Table 3, it can be determined that the first switch tube S11 is broken down or driven normally high, that is, the first switch tube S11 is short-circuited. If the real-time output voltage V obtained in step 2 of Table 1 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 2 acis not 100V; then, referring to Table 3, it can be determined that the driving of the first switch tube S11 fails, that is, the first switch tube S11 is open-circuited.

[0069] If the real-time output voltage V obtained in step 4 of Table 1 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 4 is ac is not 0V; then, referring to Table 3, it can be determined that the second switch tube S12 is broken down or driven normally high, that is, the second switch tube S12 is short-circuited. If the real-time output voltage V obtained in step 5 of Table 1 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 5 ac If the Vac voltage is not -100V, then referring to Table 3, it can be determined that the driving of the second switch tube S12 fails, that is, the second switch tube S12 is open. At the same time, the real-time Vac voltage obtained in step 1 of Table 1 is abnormal (for example, -100V), which can also be judged as the second switch tube S12 being short-circuited.

[0070] If the real-time positive bus voltage V obtained in step 2 of Table 1 is bus+ is inconsistent with the initial positive bus voltage, that is, the real-time positive bus voltage V obtained in step 2 bus+ is not 100V; then, referring to Table 3, it can be determined that the third switch tube S13 is broken down or driven normally high, that is, the third switch tube S13 is short-circuited. ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 3 is ac If the voltage Vac is not 0V, then referring to Table 3, it can be determined that the driving of the third switch tube S13 is invalid, that is, the third switch tube S13 is open. At the same time, the real-time Vac voltage obtained in step 6 of Table 1 is abnormal, and it can also be determined that the diode connected in parallel with the third switch tube S13 is open.

[0071] If the real-time negative bus voltage V obtained in step 5 of Table 1 is bus- is inconsistent with the initial negative bus voltage, that is, the real-time negative bus voltage V obtained in step 5 bus- is not -100V; then, referring to Table 3, it can be determined that the fourth switch tube S14 is broken down or driven normally high, that is, the fourth switch tube S14 is short-circuited. If the real-time output voltage V obtained in step 6 of Table 1 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 6 acIf the voltage Vac is not 0V, then referring to Table 3, it can be determined that the driving of the fourth switch tube S14 is invalid, that is, the fourth switch tube S14 is open. At the same time, the real-time Vac voltage obtained in step 3 of Table 1 is abnormal, and it can also be determined that the diode connected in parallel with the fourth switch tube S14 is open.

[0072] It should be noted that Table 4 corresponds to Figure 3 and Table 2. Follow steps 1 to 8 shown in Table 2 to Figure 3 After detecting the circuit topology structure in the circuit, it can be determined whether each switch device has an abnormality according to the rules shown in Table 4.

[0073] Table 4

[0074]

[0075] In the embodiment of the present application, if the real-time positive bus voltage V obtained in step 4 of Table 2 is bus+ is inconsistent with the initial positive bus voltage, that is, the real-time positive bus voltage V obtained in step 4 bus+ is not 100V; then, referring to Table 4, it can be determined that the fifth switch tube S21 is broken down or driven normally high, that is, the fifth switch tube S21 is short-circuited. ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 3 is ac is not 100V; then, referring to Table 4, it can be determined that the driving of the fifth switch tube S21 fails, that is, the fifth switch tube S21 is open.

[0076] If the real-time output voltage V obtained in step 2 of Table 2 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 2 ac is not 0V; then, referring to Table 4, it can be determined that the sixth switch tube S22 is broken down or driven normally high, that is, the switch tube S22 is short-circuited. If the real-time output voltage V obtained in step 3 of Table 2 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 3 is ac is not 100 V; then, referring to Table 4, it can also be determined that the driving of the sixth switch tube S22 fails, that is, the sixth switch tube S22 is open.

[0077] If the real-time output voltage V obtained in step 6 of Table 2 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 6 acis not 0V; then, referring to Table 4, it can be determined that the seventh switch tube S23 is broken down or driven normally high, that is, the seventh switch tube S23 is short-circuited. If the real-time output voltage V obtained in step 7 of Table 2 ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 7 ac is not -100 V; then, referring to Table 4, it can be determined that the driving of the seventh switch tube S23 fails, that is, the seventh switch tube S23 is open.

[0078] If the real-time negative bus voltage V obtained in step 8 of Table 2 is bus- is inconsistent with the initial negative bus voltage, that is, the real-time negative bus voltage V obtained in step 8 bus- is not -100V; then, referring to Table 4, it can be determined that the eighth switch tube S24 is broken down or driven normally high, that is, the eighth switch tube S24 is short-circuited. ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 7 is ac is not -100 V; then, referring to Table 4, it can be determined that the driving of the eighth switch tube S24 fails, that is, the eighth switch tube S24 is open.

[0079] If the real-time positive bus voltage V obtained in step 2 of Table 2 is bus+ is inconsistent with the initial positive bus voltage, that is, the real-time positive bus voltage V obtained in step 2 bus+ is not 100V; then, referring to Table 4, it can be determined that diode S25 is short-circuited. If the real-time output voltage V obtained in step 8 of Table 2 is ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 8 is ac is not 0V; then, referring to Table 4, it can be determined that diode S25 is open.

[0080] If the real-time negative bus voltage V obtained in step 6 of Table 2 is bus- is inconsistent with the initial negative bus voltage, that is, the real-time negative bus voltage V obtained in step 6 bus- is not -100V; then, referring to Table 4, it can be determined that diode S26 is short-circuited. If the real-time output voltage V obtained in step 4 of Table 2 is ac and the expected output voltage (expected V ac ) is inconsistent, that is, the real-time output voltage V obtained in step 4 is ac is not 0V; then, referring to Table 4, it can be determined that diode S26 is open.

[0081] It should be noted that Figure 4 The topological structure of the T-type three-level three-phase inverter circuit is shown in FIG. The T-type three-level three-phase inverter circuit is composed of three groups of T-type three-level single-phase inverter circuits superimposed on each other. Specifically, Figure 4 , the switching devices VA1, VA2, VA3 and VA4 belong to the first group of T-type three-level single-phase inverter circuits, the switching devices VB1, VB2, VB3 and VB4 belong to the second group of T-type three-level single-phase inverter circuits, and the switching devices VC1, VC2, VC3 and VC4 belong to the third group of T-type three-level single-phase inverter circuits. Therefore, for Figure 4 The circuit shown is used for testing. Figure 2 The detection process of the circuit shown will not be described in detail here.

[0082] Correspondingly, for the I-type three-level three-phase inverter circuit, you can also refer to Figure 3 The I-type three-level single-phase inverter circuit shown is used for detection, which will not be described in detail here.

[0083] It should also be noted that the circuit to be tested in the embodiments of the present application may include: an inverter circuit and / or a rectifier circuit. Since the rectifier circuit corresponds to the inverter circuit, the rectifier circuit can be a conversion circuit that converts AC power into DC power; that is, the output end of the inverter circuit can be used as the input end of the rectifier circuit, and the input end of the inverter circuit can be used as the output end of the rectifier circuit. Therefore, for the detection of the rectifier circuit, the detection of the inverter circuit ( Figures 2 to 4 The detection process of the circuit topology structure shown in FIG. 1 is not described in detail here.

[0084] It should also be noted that the switch device in the embodiment of the present application may include at least one of an IGBT (Insulate-Gate Bipolar Transistor), a MOS tube (Metal-Oxide-Semiconductor Field-Effect Transistor) and a diode. For example, Figure 2 The switches S11, S12, S13 and S14 shown, and Figure 3 The switch tubes S21, S22, S23 and S24 shown may be IGBTs or MOS tubes; Figure 3 S25 and S26 shown may be diodes.

[0085] In the embodiment of the present application, the bus voltage can be used to detect the state of the device, so the condition of the switching device in the circuit to be tested can be detected more comprehensively.

[0086] It is understandable that the detection method provided in the embodiment of the present application can effectively detect the abnormal state of the switch device, so that the switch device can be repaired or replaced in time to ensure the normal operation of the circuit. For example, the inverter circuit can be detected when the device is turned on. If there is no abnormality in the device in the inverter circuit, the device can be turned on normally; if there is an abnormality in the device in the inverter circuit, it is necessary to shut down in time for repair or replacement.

[0087] In an embodiment of the present application, before the device is turned on, a smaller voltage can be used to pre-charge the bus of the circuit to be tested in the device, and then the devices of the circuit to be tested can be detected. In this way, the abnormal state of the device can be detected in advance, and the impact on the circuit caused by the abnormal device can be prevented.

[0088] Figure 5 A schematic diagram of the structure of a switch device health detection device provided in an embodiment of the present application is shown in FIG. Figure 5 As shown, the device 200 for detecting the health of a switching device includes: a pre-charging module 210 , an adjustment module 220 , a measurement module 230 and a judgment module 240 .

[0089] The pre-charging module 210 is configured to pre-charge the bus of the circuit under test to the initial bus voltage. The adjusting module 220 is configured to change the working state of each switch device in the circuit under test according to a preset rule. The measuring module 230 is configured to measure the real-time bus voltage and output voltage. The judging module 240 is configured to judge whether there is an abnormality in the switch device based on the real-time bus voltage and output voltage.

[0090] In an embodiment of the present application, the preset rules are formulated according to the position of the switching device in the circuit to be tested. The preset rules represent the order of changing the working state of each switching device. The preset rules include: positive half-cycle detection for the positive half-cycle circuit, and negative half-cycle detection for the negative half-cycle circuit. Among them, in the positive half-cycle detection, the output voltage is greater than or equal to 0; in the negative half-cycle detection, the output voltage is less than or equal to 0.

[0091] In some embodiments of the present application, the judgment module 240 is also configured to judge whether there is an abnormality in the switching device on the positive half-cycle circuit when the circuit to be tested is subjected to a positive half-cycle detection; and / or, to judge whether there is an abnormality in the switching device on the negative half-cycle circuit when the circuit to be tested is subjected to a negative half-cycle detection.

[0092] In some embodiments of the present application, the adjustment module 220 is further configured to change the working state of each switch device in the circuit to be tested according to a preset rule starting from the initial state. In the initial state, each switch device is in the closed state.

[0093] In some embodiments of the present application, the judgment module 240 is also configured to judge that there is an abnormality in the switching device if the real-time bus voltage is inconsistent with the initial bus voltage; and / or judge that there is an abnormality in the switching device if the real-time output voltage is inconsistent with the expected output voltage.

[0094] In some embodiments of the present application, the initial bus voltage is determined based on the maximum withstand voltage of each switch device in the circuit to be tested. The second preset voltage is the initial bus voltage, and the expected output voltage is determined according to the initial bus voltage.

[0095] In some embodiments of the present application, the switching device includes at least one of an IGBT, a MOS tube and a diode.

[0096] Figure 6 A schematic diagram of the structure of a power conversion device provided in an embodiment of the present application is shown in FIG. Figure 6 As shown, the power conversion device 300 includes: a detection device 200 for the health of a switching device.

[0097] In the present application examples, reference Figure 6 The power conversion device 300 further includes: a circuit to be tested 100. The circuit to be tested 100 may include: an inverter circuit and / or a rectifier circuit.

[0098] It should be understood that "one embodiment" or "an embodiment" mentioned throughout the specification means that specific features, structures or characteristics related to the embodiment are included in at least one embodiment of the present application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. In addition, these specific features, structures or characteristics can be combined in one or more embodiments in any suitable manner. It should be understood that in various embodiments of the present application, the size of the serial number of each step / process mentioned above does not mean the order of execution, and the execution order of each step / process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiment of the present application. The serial numbers of the embodiments of the present application mentioned above are for description only and do not represent the advantages and disadvantages of the embodiments.

[0099] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.

[0100] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or components can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the devices or units can be electrical, mechanical or other forms.

[0101] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units; they may be located in one place or distributed on multiple network units; some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0102] In addition, all functional units in the embodiments of the present application can be integrated into one processing unit, or each unit can be a separate unit, or two or more units can be integrated into one unit; the above integrated unit can be implemented in the form of hardware or in the form of hardware plus software functional units. A person of ordinary skill in the art can understand that all or part of the steps of the above method embodiments can be completed by hardware related to program instructions, and the above program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above method embodiments are executed; and the above storage medium includes: mobile storage devices, read-only memory (ROM), disks or optical disks, etc. Various media that can store program codes.

[0103] Alternatively, if the above-mentioned integrated unit of the present application is implemented in the form of a software function module and sold or used as an independent product, it can also be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially or in other words, the part that contributes to the relevant technology can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as mobile storage devices, ROMs, magnetic disks, or optical disks.

[0104] The above is only an implementation method of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for detecting the health of a switching device, characterized in that: include: Pre-charging the bus of the circuit to be tested to an initial bus voltage; According to the preset rules, the working state of each switch device in the circuit to be tested is changed, so that the expected output voltage alternately jumps between the first preset voltage and the second preset voltage, and the real-time bus voltage and output voltage are measured; wherein the preset rules are formulated according to the positions of the switch devices in the circuit to be tested; the preset rules represent the order of changing the working state of each switch device; Based on the real-time bus voltage and the output voltage, it is determined whether the switching device is abnormal.

2. The method for detecting the health of a switching device according to claim 1, characterized in that: Changing the working state of each of the switch devices in the circuit to be tested according to the preset rule includes: Starting from the initial state, the working state of each of the switch devices in the circuit to be tested is changed according to the preset rule; wherein, in the initial state, each of the switch devices is in the closed state.

3. The method for detecting the health of a switching device according to claim 1, characterized in that: Based on the real-time bus voltage and the output voltage, judging whether the switch device in the circuit to be tested is abnormal includes: If the real-time bus voltage is inconsistent with the initial bus voltage, it is determined that the switch device is abnormal; and / or, If the real-time output voltage is inconsistent with the expected output voltage, it is determined that the switch device is abnormal.

4. The method for detecting the health of a switching device according to claim 1, characterized in that: The preset rules include: positive half-cycle detection for positive half-cycle circuits, and negative half-cycle detection for negative half-cycle circuits; Judging whether the switch device is abnormal based on the real-time bus voltage and the output voltage includes: In the case of performing the positive half-cycle detection on the circuit to be tested, determining whether the switch device on the positive half-cycle circuit is abnormal; wherein, in the positive half-cycle detection, the output voltage is greater than or equal to 0; and / or, When the negative half-cycle detection is performed on the circuit to be tested, it is determined whether the switching device on the negative half-cycle circuit is abnormal; wherein, in the negative half-cycle detection, the output voltage is less than or equal to 0.

5. The method for detecting the health of a switching device according to claim 1, characterized in that: The initial bus voltage is determined based on the maximum withstand voltage of each of the switching devices in the circuit to be tested; the second preset voltage is the initial bus voltage, and the expected output voltage is determined based on the initial bus voltage.

6. The method for detecting the health of a switching device according to claim 4, characterized in that: The circuit to be tested comprises: a T-type three-level single-phase inverter circuit; the T-type three-level single-phase inverter circuit comprises: a first switch tube, a second switch tube, a third switch tube and a fourth switch tube; wherein the first switch tube and the second switch tube are connected in series; the third switch tube and the fourth switch tube are connected in series; one end of the third switch tube is connected to the connection point between the first switch tube and the second switch tube; The positive half-cycle detection includes: closing all switch tubes of the T-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; opening the first switch tube, and measuring the bus voltage and the output voltage; closing the first switch tube, opening the third switch tube, and measuring the bus voltage and the output voltage; The negative half-cycle detection includes: closing all switch tubes of the T-type three-level single-phase inverter circuit and measuring the bus voltage and the output voltage; turning on the second switch tube and measuring the bus voltage and the output voltage; closing the first switch tube, turning on the fourth switch tube, and measuring the bus voltage and the output voltage.

7. The method for detecting the health of a switching device according to claim 4, characterized in that: The circuit to be tested comprises: an I-type three-level single-phase inverter circuit; the I-type three-level single-phase inverter circuit comprises: a fifth switch tube, a sixth switch tube, a seventh switch tube and an eighth switch tube connected in series in sequence; The positive half-cycle detection includes: closing all the switch tubes of the I-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; opening the fifth switch tube, and measuring the bus voltage and the output voltage; opening the sixth switch tube, and measuring the bus voltage and the output voltage; closing the fifth switch tube, opening the seventh switch tube, and measuring the bus voltage and the output voltage; The negative half-cycle detection includes: closing all the switch tubes of the I-type three-level single-phase inverter circuit, and measuring the bus voltage and the output voltage; turning on the eighth switch tube, and measuring the bus voltage and the output voltage; turning on the seventh switch tube, and measuring the bus voltage and the output voltage; closing the eighth switch tube, turning on the sixth switch tube, and measuring the bus voltage and the output voltage.

8. A device for detecting the health of a switching device, characterized in that: include: A pre-charging module is configured to pre-charge a bus of the circuit to be tested to an initial bus voltage; An adjustment module is configured to change the working state of each switch device in the circuit to be tested according to a preset rule, so that the expected output voltage alternately jumps between a first preset voltage and a second preset voltage; wherein the preset rule is formulated according to the position of the switch device in the circuit to be tested; and the preset rule represents the order of changing the working state of each switch device; A measurement module is configured to measure a real-time bus voltage and an output voltage; The judgment module is configured to judge whether the switching device is abnormal based on the real-time bus voltage and the output voltage.

9. The device for detecting the health of a switching device according to claim 8, characterized in that: The judgment module is further configured to judge that there is an abnormality in the switching device if the real-time bus voltage is inconsistent with the initial bus voltage; and / or judge that there is an abnormality in the switching device if the real-time output voltage is inconsistent with the expected output voltage.

10. A power conversion device, characterized in that: include: The device for detecting the health of a switching device as claimed in claim 8 or 9.

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