A method, apparatus and equipment for diagnosing open-circuit faults in power transistors

Abstract

This invention provides a method, apparatus, and device for diagnosing open-circuit faults in power transistors. The method includes: determining a first voltage trajectory diagram of the line voltage output by a locomotive inverter under normal operating conditions in an α-β coordinate system; determining the magnitude relationship between the three-phase modulation waves of the locomotive inverter when an open-circuit fault occurs in a power transistor; identifying a special region in the first voltage trajectory diagram based on the magnitude relationship between the three-phase modulation waves, with different magnitude relationships between the three-phase modulation waves corresponding to different special regions; calculating and determining a second voltage trajectory diagram of the line voltage based on the special region, the second voltage trajectory diagram being a part of the first voltage trajectory diagram, with different second voltage trajectory diagrams corresponding to different power transistors in the open-circuit state; and identifying the target power transistor in the open-circuit state based on the second voltage trajectory diagram. The method, apparatus, and device of this invention can quickly and effectively diagnose open-circuit faults in locomotive inverters.

Description

Technical Field

[0001] This invention belongs to the field of open circuit diagnosis technology for locomotive inverters, specifically relating to a method, device, and equipment for diagnosing open circuit faults in power transistors. Background Technology

[0002] Since the 1960s, semiconductor traction converter technology has been widely used in trains, becoming one of the hallmarks of locomotive advancement and reliability. However, with the popularization of converter technology, the problem of main circuit device failures has gradually become prominent. Currently, nearly 38% of converter system failures are directly or indirectly caused by semiconductor power electronic device faults, most of which manifest as open-circuit faults. Existing fault diagnosis systems installed in train models are mainly used for train operation monitoring and recording, and have not fully realized online self-diagnosis functions, requiring manual diagnosis and fault location based on the experience of engineers. Therefore, it is necessary to conduct research on online fault diagnosis for locomotive converter systems to ensure driving safety, improve maintenance efficiency, and reduce operating costs. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method, apparatus and equipment for diagnosing open-circuit faults of power transistors in locomotive inverters that can quickly and effectively diagnose open-circuit faults of power transistors.

[0004] The present invention includes a method for diagnosing open-circuit faults in power transistors, comprising:

[0005] Determine the first voltage trajectory diagram of the line voltage output by the locomotive inverter under normal operating conditions in the α-β coordinate system;

[0006] When an open-circuit fault occurs in a power transistor, determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter.

[0007] Based on the magnitude relationship between the three-phase modulation waves, a special region is determined in the first voltage trajectory diagram. Different magnitude relationships between the three-phase modulation waves correspond to different special regions.

[0008] The second voltage trajectory diagram of the line voltage is calculated and determined based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors in the open circuit state are different.

[0009] The target power transistor in an open-circuit state is determined based on the second voltage trajectory diagram.

[0010] As an optional embodiment, the first voltage trajectory diagram is a circle with its center at the origin of the α-β coordinate system and a radius of a first value.

[0011] As an optional embodiment, the functional relationship corresponding to the first voltage trajectory diagram is:

[0012]

[0013] Wherein, the U m U is the amplitude of the sine wave. α (t) and U β (t) represent the two sinusoidal line voltages of the locomotive inverter.

[0014] As an optional embodiment, the three-phase modulated wave is denoted as u. ra u rb u rc ω is the modulation wave angular frequency. When an open-circuit fault occurs in the upper bridge arm of the locomotive inverter, the relationship between the three-phase modulation waves satisfies:

[0015] u rc >u rb >u ra The corresponding special area is

[0016] u rc >u rb >u ra The corresponding special area is

[0017] As an optional embodiment, when an open-circuit fault occurs in the lower bridge arm of the locomotive inverter, the relationship between the three-phase modulation waves satisfies:

[0018] u rc rb ra The corresponding special area is

[0019] u rc ra rb The corresponding special area is

[0020] As an optional embodiment, the step of calculating and determining the second voltage trajectory diagram of the line voltage based on the special region includes:

[0021] The third voltage trajectory of the line voltage in the α-β coordinate system is calculated and determined as follows:

[0022]

[0023] u α (t) and u β (t) represents the sinusoidal line voltage in the α-β coordinate system;

[0024] ​​​​After horizontally flipping the third voltage trajectory in the α-β coordinate system, and then rotating it clockwise by 60°, the fourth voltage trajectory of the line voltage in the α'-β' coordinate system is calculated.

[0025]

[0026] Based on the fourth voltage trajectory, a second voltage trajectory diagram of the line voltage in the special region is calculated and determined.

[0027] As an optional embodiment, the step of calculating and determining the second voltage trajectory map of the line voltage located in the special region based on the fourth voltage trajectory includes:

[0028] Based on the calculation of the fourth voltage trajectory, the fourth voltage trajectory diagram of the line voltage in the special region is determined as the first line segment on the α' axis in the α'-β' coordinate system;

[0029] Transforming the line segment to the α-β coordinate system yields the corresponding second line segment. This second line segment represents the second voltage trajectory of the line voltage in a special region. The second voltage trajectory passes through the origin in the α-β coordinate system and has a slope of [missing information]. or line segments;

[0030] The second voltage trajectory diagram is obtained by dividing the first voltage trajectory diagram based on the second voltage trajectory and the corresponding special region.

[0031] As an optional embodiment, when the obtained second voltage trajectory diagram is at least two, it represents at least two different target power transistors, and the voltage trajectory when the at least two different target power transistors are open-circuit faults is the intersection of the second voltage trajectories of each target power transistor.

[0032] Another embodiment of the present invention also provides a power transistor open-circuit fault diagnosis device, comprising:

[0033] The first determining module is used to determine the first voltage trajectory diagram of the line voltage output by the locomotive inverter under normal operating conditions in the α-β coordinate system;

[0034] The second determining module is used to determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter when an open-circuit fault occurs in a power transistor.

[0035] The third determining module is used to determine a special region in the first voltage trajectory diagram based on the magnitude relationship between the three-phase modulation waves. Different magnitude relationships between the three-phase modulation waves correspond to different special regions.

[0036] The calculation module is used to calculate and determine the second voltage trajectory diagram of the line voltage based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors in the open circuit state are different.

[0037] The fourth determining module is used to determine the target power transistor in an open-circuit state based on the second voltage trajectory diagram.

[0038] Another embodiment of the present invention also provides an electronic device, comprising:

[0039] At least one processor; and,

[0040] A memory that is communicatively connected to the at least one processor;

[0041] The memory stores instructions executable by the at least one processor, the instructions being configured to perform the power transistor open-circuit fault diagnosis method as described in any of the preceding descriptions.

[0042] The beneficial effect of this invention lies in the fact that the proposed method takes into account the already fixed equipment on the locomotive. Therefore, it only needs to utilize the two voltage sensors already present in the locomotive inverter to determine the line voltage trajectory of the locomotive inverter to diagnose and locate open circuit faults in a single power transistor or both power transistors. No modification to the locomotive equipment is required to obtain system control signals or additional diagnostic variables. Furthermore, the method of this application uses the output line voltage trajectory diagram as the diagnostic variable, which is largely unaffected by load changes. The diagnostic method of this application remains effective under no-load and light-load conditions.

[0043] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures particularly pointed out in the written description, claims, and drawings.

[0044] The technical solution of this application will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0045] The accompanying drawings are provided to further illustrate the present application and form part of the specification. They are used together with the embodiments of the present application to explain the application and do not constitute a limitation thereof. In the drawings:

[0046] Figure 1 This is a schematic diagram of the method flow in an embodiment of the present invention.

[0047] Figure 2 This is a simplified circuit diagram of the locomotive inverter in an embodiment of the present invention.

[0048] Figure 3 This is a topology diagram of the VT5 fault in an embodiment of the present invention.

[0049] Figure 4 This is a topology diagram of the VT6 fault in an embodiment of the present invention.

[0050] Figure 5 This is a schematic diagram of the output voltage trajectory when a single power transistor experiences an open-circuit fault in an embodiment of the present invention.

[0051] Figure 6 This is a schematic diagram of the output voltage trajectory when two power transistors experience an open-circuit fault in an embodiment of the present invention.

[0052] Figure 7 A block diagram of the device structure in an embodiment of the present invention. Detailed Implementation

[0053] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but these are not intended to limit the scope of the invention.

[0054] It should be understood that various modifications can be made to the embodiments disclosed herein. Therefore, the following description should not be considered as limiting, but merely as an example of embodiments. Other modifications within the scope and spirit of this disclosure will be apparent to those skilled in the art.

[0055] The accompanying drawings, which are included in and form part of this specification, illustrate embodiments of the present disclosure and, together with the general description of the disclosure given above and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.

[0056] These and other features of the invention will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0057] It should also be understood that although the invention has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of the invention, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0058] The above and other aspects, features and advantages of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0059] Specific embodiments of the present disclosure are described thereafter with reference to the accompanying drawings; however, it should be understood that the disclosed embodiments are merely examples of the present disclosure and can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to avoid unnecessary or redundant details that could obscure the present disclosure. Therefore, the specific structural and functional details disclosed herein are not intended to be limiting, but merely to serve as the basis and representative basis for the claims to teach those skilled in the art to use the present disclosure in a variety of substantially any suitable detailed structures.

[0060] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in still another embodiment,” all of which may refer to one or more of the same or different embodiments according to this disclosure.

[0061] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0062] like Figure 1 As shown, an embodiment of the present invention provides a method for diagnosing open-circuit faults in power transistors, including:

[0063] S1: Determine the first voltage trajectory diagram of the line voltage output by the locomotive inverter under normal operating conditions in the α-β coordinate system;

[0064] S2: When an open-circuit fault occurs in a power transistor, determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter;

[0065] S3: Determine a special region in the first voltage trajectory diagram based on the magnitude relationship between the three-phase modulation waves. Different special regions correspond to different magnitude relationships between the three-phase modulation waves.

[0066] S4: Calculate and determine the second voltage trajectory diagram of the line voltage based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors are different in the open circuit state.

[0067] S5: Determine the target power transistor in an open-circuit state based on the second voltage trajectory diagram.

[0068] The beneficial effect of this embodiment is that the proposed method takes into account the already fixed equipment on the locomotive. Therefore, it only needs to use the two voltage sensors already in the locomotive inverter to determine the line voltage trajectory of the locomotive inverter to diagnose and locate open circuit faults in a single power transistor or both power transistors. No modification to the locomotive equipment is required to obtain system control signals or additional diagnostic variables. Furthermore, the method of this application uses the output line voltage trajectory diagram as the diagnostic variable, which is basically unaffected by load changes. The diagnostic method of this application remains effective under no-load and light-load conditions.

[0069] For example, the embodiments of this application use a 25T locomotive inverter as an example for description, and the simplified circuit diagram of the locomotive inverter is as follows. Figure 2 As shown. Input voltage u dc (t) represents 600V DC, with an output voltage of three-phase 380V / 50Hz, using SPWM modulation and closed-loop voltage control. L1 and R1 form a pre-charge circuit; after pre-charging, contactor KM2 closes. C1-C4 and R3-R6 are DC-side support capacitor assemblies used to stabilize the inverter input voltage. KM3 and R2 form a discharge circuit; when the inverter stops working, contactor KM3 closes, releasing the energy stored in the support capacitors. VT1-VT6 are fully controlled power transistors, each with anti-parallel diodes VD1-VD6. C a ~C c These are three-phase non-inductive capacitors, L a ~L c These are three-phase filter inductors. Output voltage u ab (t) and u bc (t) is obtained by voltage sensors TV201 and TV202 respectively.

[0070] According to Kirchhoff's laws, the inverter output line voltage can be calculated using the following formula:

[0071]

[0072] Among them, u VT1 (t)~u VT6 (t) represents the voltage across VT1 to VT6 respectively; tr a (t)~tr c (t) represent the three-phase control signals. A value of 1 indicates that the upper bridge arm is turned on and the lower bridge arm is turned off, while a value of 0 indicates the opposite. It can be seen that under normal operating conditions, the inverter output line voltage is u. dc , 0 and -u dc .

[0073] Taking the α-β transformation of equation (1), we have:

[0074]

[0075] At this time, u α (t) and u β (t) A square wave can be converted into a sine wave using the following transfer function:

[0076]

[0077] Where R, L, and C represent the resistor, filter inductor, and filter capacitor, respectively. The sine wave form u... α (t) and u β(t) can be written as:

[0078]

[0079] Where Um is the amplitude of the sine wave, and ω is the frequency of the modulation wave angular frequency. U is the phase angle. α (t) and U β (t) represent the two sinusoidal line voltages of the locomotive inverter. At this time, the functional relationship corresponding to the first voltage trajectory diagram is:

[0080]

[0081] Therefore, under normal operating conditions, the line voltage u ab (t) and u bc (t) The voltage trajectory formed in the α-β coordinate system is a circle with its center at the origin and a fixed radius. This fixed value is not fixed and can be determined according to the actual line voltage.

[0082] Furthermore, with Figure 3 As shown in the example, let the three-phase modulation wave be denoted as u. ra u rb u rc When a power transistor experiences an open-circuit fault, the voltage trajectory will be distorted. The shape and degree of distortion will vary depending on the location or number of faulty power transistors. Due to the use of closed-loop voltage control, the output line voltage is less affected by the load. For ease of fault analysis, assume that the inverter output terminals a, b, and c are directly connected to a three-phase resistive load with equal resistance.

[0083] When an open-circuit fault occurs in the upper arm of the locomotive inverter, such as a fault in phase C VT5, according to the three-phase modulation waveform u ra u rb u rc The size relationship can determine two special regions:

[0084] 1)u rc >u rb >u ra The corresponding special area is

[0085] In this region, tr a (t)~tr c (t) has 4 different combinations.

[0086] When tr a (t)=tr b (t)=tr c When (t) = 0, as Figure 3 As shown in (1), the lower bridge arms of phases a, b, and c are conducting, uVT1 =u VT3 =u dc u VT4 =u VT6 =0, u is calculated from equation (1) ab =u bc =0.

[0087] When tr a (t)=tr b (t)=0,tr c When (t) = 1, as Figure 3 As shown in (2), the lower bridge arms of phases a and b are conducting but no current flows, and phase c also has no current flowing due to the open circuit of VT5. At this time, there is u VT1 =u VT3 =u dc u VT4 =u VT6 =0, u is calculated from equation (1) ab =u bc =0.

[0088] When tr a (t)=0,tr b (t)=tr c When (t) = 1, as Figure 3 As shown in (3), the lower bridge arm of phase a is conducting, and the upper bridge arm of phase b is conducting. Current flows in through the upper bridge arm of phase b and flows out through the lower bridge arm of phase a. Phase c is still not directly connected to the DC side, but the upper and lower bridge arms each bear half of the DC side voltage. At this time, u VT1 =u VT4 =u dc u VT3 =0, u VT6 =u dc / 2, u is calculated from equation (1) ab =-u dc u bc =u dc / 2.

[0089] When tr a (t)=tr b (t)=tr c When (t) = 1, as Figure 3 As shown in (4), the upper bridge arms of phases a and b are conducting but no current flows, and phase c also has no current flowing because VT5 is open. At this time, u VT1 =u VT3 =0, u VT4 =u VT6 =u dc u can be calculated from equation (1) ab =u bc =0.

[0090] 2)u rc >u rb >u ra The corresponding special area is

[0091] In this region, tr a (t)~tr c (t) also has 4 different combinations, 3 of which are related to u. rc >u rb >u ra At the same time, the equivalent topology corresponding to each combination is as follows: Figure 3 As shown in (1), (2), and (4). For combinations specific to this region, when tr a (t)=tr c (t)=1,tr b When (t) = 0, as Figure 3 As shown in (5), the upper bridge arm of phase a is conducting, and the lower bridge arm of phase b is conducting. Current flows in through the upper bridge arm of phase a and out through the lower bridge arm of phase b. Phase c is not directly connected to the DC side, but the upper and lower bridge arms each bear half of the DC side voltage. At this time, u VT1 =u VT4 =0, u VT3 =u dc u VT6 =u dc / 2, u is calculated from equation (1) ab =u dc u bc =-u dc / 2.

[0092] The output line voltage under the two special regions and the calculation results after α-β transformation show that, under these two special regions, u α The value of (t) is normal, while u β The value of (t) is always 0. Since the two special regions together account for one-third of a single cycle, the U calculated by equation (3) β (t) will gradually approach zero over a period of time, thus the voltage trajectory in the special region under the open-circuit fault of VT5 can be approximated as a line segment on the axis. In the normal region, u β The value of (t) can be obtained from equation (2), which shows that it is always greater than zero, i.e., U β Since (t) is greater than zero, the voltage trajectory in the normal region is a semicircle of the positive half-axis of β. The entire voltage trajectory can be represented as:

[0093]

[0094] When an open-circuit fault occurs in the lower bridge arm of the locomotive inverter, such as a VT6 fault, according to the three-phase modulation waveform u rau rb u rc The size relationship can determine two special regions:

[0095] 1)u rc rb ra The corresponding special area is

[0096] In this region, tr a (t)~tr c (t) has 4 different combinations.

[0097] When tr a (t)=tr b (t)=tr c When (t) = 0, as Figure 4 As shown in (1), the lower bridge arms of phases a and b are conducting but no current flows, and phase c VT6 is open and no current flows either. At this time, u VT1 =u VT3 =u dc u VT4 =u VT6 =0, u is calculated from equation (1) ab =u bc =0.

[0098] When tr a (t)=1, tr b (t)=tr c When (t) = 0, as Figure 4 As shown in (2), the upper bridge arm of phase a is conducting, and the lower bridge arm of phase b is conducting. Current flows in through the upper bridge arm of phase a and out through the lower bridge arm of phase b. Phase c is still not directly connected to the DC side, but the upper and lower bridge arms each bear half of the DC side voltage. At this time, u VT1 =u VT4 =0, u VT3 =u dc u VT6 =u dc / 2, u is calculated from equation (1) ab =u dc u bc =-u dc / 2.

[0099] When tr a (t)=tr b (t)=1, tr c When (t) = 0, as Figure 4 As shown in (3), the upper bridge arms of phases a and b are conducting but no current flows, and VT6 in phase c is open and no current flows either. At this time, u VT1 =u VT3 ​​=0, u VT4 =u VT6 =u dc u can be calculated from equation (1) ab =u bc =0.

[0100] When tr a (t)=tr b (t)=tr c When (t) = 1, as Figure 4 As shown in (4), the upper bridge arms of phases a, b, and c are conducting but no current flows. At this time, u VT1 =u VT3 =0, u VT4 =u VT6 =u dc u can be calculated from equation (1) ab =u bc =0.

[0101] 2)u rc ra rb The corresponding special area is

[0102] In this region, tr a (t)~tr c (t) also has 4 different combinations, 3 of which are related to u. rc rb ra At the same time, the equivalent topology corresponding to each combination is as follows: Figure 4 As shown in (1), (3), and (4). For combinations specific to this region, when tr a (t)=tr c (t)=0,tr b When (t) = 1, as Figure 4 As shown in (5), the lower bridge arm of phase a is conducting, and the upper bridge arm of phase b is conducting. Current flows in through the upper bridge arm of phase b and flows out through the lower bridge arm of phase a. Phase c is still not directly connected to the DC side, but the upper and lower bridge arms each bear half of the DC side voltage. At this time, u VT1 =u VT4 =u dc u VT3 =0, u VT6 =u dc / 2, u is calculated from equation (1) ab =-u dc u bc =u dc / 2.

[0103] ​​​​The output line voltage under the two special regions and the calculation results after α-β transformation show that, under these two special regions, u α The value of (t) is normal, while u β The value of (t) is always 0. Since the two special regions together account for one-third of a single cycle, the U calculated by equation (3) β (t) will gradually approach zero over a period of time, thus it can be concluded that the voltage trajectory in the special region during an open-circuit fault of VT6 is also approximately a line segment on the α axis. In the normal region, u β The value of (t) can be determined from equation (2) to be always less than zero, i.e., U β Since (t) is less than zero, the voltage trajectory in the normal region is a semicircle of the negative half-axis of β. The entire voltage trajectory can be represented as...

[0104]

[0105] In another embodiment, the step of calculating and determining the second voltage trajectory based on the special region includes:

[0106] S6: Calculate and determine the third voltage trajectory of the line voltage in the α-β coordinate system as follows:

[0107]

[0108] u α (t) and u β (t) represents the sinusoidal line voltage in the α-β coordinate system;

[0109] S7: After horizontally flipping the third voltage trajectory in the α-β coordinate system, rotate it 60° clockwise to calculate the fourth voltage trajectory of the line voltage in the α'-β' coordinate system;

[0110]

[0111] S8: Calculate and determine the second voltage trajectory diagram of the line voltage in the special region based on the fourth voltage trajectory.

[0112] The step of calculating and determining the second voltage trajectory diagram of the line voltage located in the special region based on the fourth voltage trajectory includes:

[0113] S9: Based on the fourth voltage trajectory, the fourth voltage trajectory diagram of the line voltage in the special region is calculated and determined as the first line segment on the α' axis in the α'-β' coordinate system;

[0114] S10: Transform the line segment to the α-β coordinate system to obtain the corresponding second line segment. The second line segment is the second voltage trajectory of the line voltage in the special region. The second voltage trajectory passes through the origin and has a slope of [value missing] in the α-β coordinate system. or line segments;

[0115] S11: Based on the second voltage trajectory and the corresponding special region, the second voltage trajectory diagram is obtained by dividing the first voltage trajectory diagram.

[0116] Specifically, when an open-circuit fault occurs in other phases, the voltage trajectory at that time can also be obtained.

[0117] Taking phase a as an example, for ease of analysis, we first prove the following theory, which gives us the following α'-β' transformation:

[0118]

[0119] The α-β coordinate system can be transformed into the α'-β' coordinate system by horizontally flipping it and then rotating it 60° clockwise.

[0120] The above process proves the following:

[0121] For example, let:

[0122]

[0123] After α-β transformation, we have:

[0124]

[0125] After the α'-β' transformation, we have:

[0126]

[0127] First, horizontally flip the α-β coordinate system. Then, rotate the flipped α-β coordinate system counterclockwise by an angle θ to obtain the α'-β' coordinate system, which is:

[0128]

[0129] Solving for:

[0130]

[0131] Therefore, the horizontally flipped α-β coordinate system can be transformed into the α'-β' coordinate system by rotating it 60° clockwise.

[0132] Furthermore, the output line voltages under two special regions and the calculated results after α'-β' transformation when VT1 or VT2 experiences an open-circuit fault are presented. The voltage trajectories in the special regions for both under open-circuit faults are approximately line segments on the α' axis, and can be expressed as follows:

[0133]

[0134] Transform them to the α-β coordinate system respectively, and we get

[0135]

[0136] Transform them to the α-β coordinate system respectively, and we get

[0137]

[0138] At this point, the voltage trajectories of both in the special region during an open-circuit fault are such that they pass through the origin in the α-β coordinate system and have a slope of [missing value]. The line segment.

[0139] Similarly, it can be deduced that when an open-circuit fault occurs in the upper and lower arms of phase b, the voltage trajectory in the special area is a line passing through the origin in the α-β coordinate system with a slope of [missing information]. The line segments, and the voltage trajectories of both in the special region during an open-circuit fault, can be represented in the α-β coordinate system as follows:

[0140]

[0141] Based on the voltage trajectory diagram of the normal section, the complete voltage trajectory diagram in the α-β coordinate system when each power transistor experiences an open-circuit fault can be referenced. Figure 5 As shown.

[0142] Furthermore, when there are at least two obtained second voltage trajectory diagrams, it represents at least two different target power transistors, and the voltage trajectory of the at least two different target power transistors when they are open-circuit faulted is the intersection of the second voltage trajectories of each target power transistor.

[0143] For example, the six power transistors in a locomotive inverter are topologically independent, or uncorrelated, with a correlation coefficient of zero. The impact of an open-circuit fault in each power transistor is also independent. Mathematically, an open-circuit fault in two power transistors can be considered as the superposition of open-circuit faults in their respective individual power transistors. Therefore, the voltage trajectory when two power transistors experience open-circuit faults must satisfy the constraints of the voltage trajectory when a single power transistor experiences an open-circuit fault. This voltage trajectory can be described by the following formula: T ij =T i ∩T j

[0144] Among them, Tij The voltage traces for two power transistors i and j when they are open-circuited are given by T. i and T j These are the voltage trajectories for open-circuit faults in individual power transistors i and j, respectively. The symbol "∩" indicates that T is taken as the voltage trajectory. i and T j The boundary trajectory of the intersection of their respective contained regions. From this, the complete voltage trajectory in the α-β coordinate system when two power transistors experience open-circuit faults can be obtained. For cases where two different power transistors fail simultaneously, refer to... Figure 6 The diagram shows all voltage traces when both power transistors have an open-circuit fault.

[0145] Based on the methods shown in the above embodiments and figures, it can be seen that when the inverter line voltage output trajectory under the correct operating conditions is calculated and determined, and the voltage trajectory diagrams for individual open-circuit faults or simultaneous faults in pairs of different power transistors are calculated based on the output trajectory, the corresponding open-circuit power transistors can be directly determined based on the voltage trajectories under different open-circuit conditions. This method is not only highly accurate but also extremely efficient. It is especially effective for inverters with fixed and unchangeable structures and has a wide range of applications.

[0146] like Figure 7 As shown, another embodiment of the present invention also provides a power transistor open-circuit fault diagnosis device 100, comprising:

[0147] The first determining module is used to determine the first voltage trajectory diagram of the line voltage output by the locomotive inverter under normal operating conditions in the α-β coordinate system;

[0148] The second determining module is used to determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter when an open-circuit fault occurs in a power transistor.

[0149] The third determining module is used to determine a special region in the first voltage trajectory diagram based on the magnitude relationship between the three-phase modulation waves. Different magnitude relationships between the three-phase modulation waves correspond to different special regions.

[0150] The calculation module is used to calculate and determine the second voltage trajectory diagram of the line voltage based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors in the open circuit state are different.

[0151] The fourth determining module is used to determine the target power transistor in an open-circuit state based on the second voltage trajectory diagram.

[0152] As an optional embodiment, the first voltage trajectory diagram is a circle with its center at the origin of the α-β coordinate system and a radius of a first value.

[0153] As an optional embodiment, the functional relationship corresponding to the first voltage trajectory diagram is:

[0154]

[0155] Wherein, the U m ω is the amplitude of the sine wave, and ω is the frequency of the modulation wave. U is the phase angle. α (t) and U β (t) represent the two sinusoidal line voltages of the locomotive inverter.

[0156] As an optional embodiment, the three-phase modulated wave is denoted as u. ra u rb u rc When an open-circuit fault occurs in the upper arm of the locomotive inverter, the relationship between the three-phase modulation waves satisfies:

[0157] u rc >u rb >u ra The corresponding special area is

[0158] u rc >u rb >u ra The corresponding special area is

[0159] As an optional embodiment, when an open-circuit fault occurs in the lower bridge arm of the locomotive inverter, the relationship between the three-phase modulation waves satisfies:

[0160] u rc rb ra The corresponding special area is

[0161] u rc ra rb The corresponding special area is

[0162] As an optional embodiment, the step of calculating and determining the second voltage trajectory diagram of the line voltage based on the special region includes:

[0163] The third voltage trajectory of the line voltage in the α-β coordinate system is calculated and determined as follows:

[0164]

[0165] u α (t) and u β (t) represents the sinusoidal line voltage in the α-β coordinate system;​​​​

[0166] After horizontally flipping the third voltage trajectory in the α-β coordinate system, and then rotating it clockwise by 60°, the fourth voltage trajectory of the line voltage in the α'-β' coordinate system is calculated.

[0167]

[0168] Based on the fourth voltage trajectory, a second voltage trajectory diagram of the line voltage in the special region is calculated and determined.

[0169] As an optional embodiment, the step of calculating and determining the second voltage trajectory map of the line voltage located in the special region based on the fourth voltage trajectory includes:

[0170] Based on the calculation of the fourth voltage trajectory, the fourth voltage trajectory diagram of the line voltage in the special region is determined as the first line segment on the α' axis in the α'-β' coordinate system;

[0171] Transforming the line segment to the α-β coordinate system yields the corresponding second line segment. This second line segment represents the second voltage trajectory of the line voltage in a special region. The second voltage trajectory passes through the origin in the α-β coordinate system and has a slope of [missing information]. or line segments;

[0172] The second voltage trajectory diagram is obtained by dividing the first voltage trajectory diagram based on the second voltage trajectory and the corresponding special region.

[0173] As an optional embodiment, when the obtained second voltage trajectory diagram is at least two, it represents at least two different target power transistors, and the voltage trajectory when the at least two different target power transistors are open-circuit faults is the intersection of the second voltage trajectories of each target power transistor.

[0174] Another embodiment of the present invention also provides an electronic device, comprising:

[0175] At least one processor; and,

[0176] A memory that is communicatively connected to the at least one processor;

[0177] The memory stores instructions executable by the at least one processor, the instructions being configured to perform the power transistor open-circuit fault diagnosis method as described in any of the embodiments above.

[0178] Another embodiment of the present invention provides a storage medium including a stored program, wherein, when the program is executed, a device including the storage medium is controlled to perform a power transistor open-circuit fault diagnosis method as described in any of the embodiments above.

[0179] This invention also provides a computer program product, which is tangibly stored on a computer-readable medium and includes computer-readable instructions. When executed, these computer-executable instructions cause at least one processor to perform a power transistor open-circuit fault diagnosis method as described in the embodiments above. It should be understood that the various solutions in this embodiment have the corresponding technical effects in the above-described method embodiments, and will not be repeated here.

[0180] It should be noted that the computer storage medium of this application can be a computer-readable signal medium or a computer-readable storage medium, or any combination thereof. Computer-readable media can be, for example, but not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatuses, or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections with one or more wires, portable computer disks, hard disks, random access storage media (RAM), read-only storage media (ROM), erasable programmable read-only storage media (EPROM or flash memory), optical fibers, portable compact disk read-only storage media (CD-ROM), optical storage media, magnetic storage media, or any suitable combination thereof. In this application, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. Computer-readable signal media can also be any computer-readable medium other than computer-readable storage media, which can send, propagate, or transmit a program configured for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, antenna, optical fiber, RF, etc., or any suitable combination thereof.

[0181] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A method for diagnosing open-circuit faults in power transistors, characterized in that, include: Determine the line voltage output of the locomotive inverter under normal operating conditions. - The trajectory of the first voltage in the coordinate system; When an open-circuit fault occurs in a power transistor, determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter. Based on the magnitude relationship between the three-phase modulation waves, a special region is determined in the first voltage trajectory diagram. Different magnitude relationships between the three-phase modulation waves correspond to different special regions. The second voltage trajectory diagram of the line voltage is calculated and determined based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors in the open circuit state are different. The target power transistor in an open-circuit state is determined based on the second voltage trajectory diagram; The second voltage trajectory diagram for calculating and determining the line voltage based on the special region includes: Calculate and determine the line voltage at - The third voltage trajectory in the coordinate system is: u ( t )and u ( t )for - Line voltage in sinusoidal form in a coordinate system; The - After the third voltage trajectory in the coordinate system is horizontally flipped, it is then rotated 60° clockwise to calculate the line voltage. '- 'The fourth voltage trajectory in the coordinate system:' ； Based on the fourth voltage trajectory, a second voltage trajectory diagram of the line voltage located in the special region is calculated and determined; The calculation and determination of the second voltage trajectory map based on the fourth voltage trajectory, which determines the line voltage in the special region, includes: Based on the fourth voltage trajectory, the fourth voltage trajectory diagram of the line voltage located in the special region is calculated as follows: '- In the coordinate system The first line segment on the axis; Convert the line segment to - The corresponding second line segment is obtained in the coordinate system. The second line segment is the second voltage trajectory of the line voltage in the special region. The second voltage trajectory is the one described in the coordinate system. - In a coordinate system, the line passes through the origin and has a slope of or line segments; The second voltage trajectory diagram is obtained by dividing the first voltage trajectory diagram based on the second voltage trajectory and the corresponding special region.

2. The power transistor open-circuit fault diagnosis method according to claim 1, characterized in that, The first voltage trajectory diagram is centered at... - The origin of the coordinate system is a circle with radius equal to the first value.

3. The power transistor open-circuit fault diagnosis method according to claim 2, characterized in that, The functional relationship corresponding to the first voltage trajectory diagram is: Wherein, the U m The amplitude of the sine wave. and These represent the two sinusoidal line voltages of the locomotive inverter.

4. The power transistor open-circuit fault diagnosis method according to claim 1, characterized in that, When there are at least two obtained second voltage trajectory diagrams, it represents at least two different target power transistors, and the voltage trajectory of the at least two different target power transistors when they are open-circuit faults is the intersection of the second voltage trajectories of each target power transistor.

5. A power transistor open-circuit fault diagnosis device, characterized in that, include: The first determining module is used to determine the line voltage output by the locomotive inverter under normal operating conditions. - The trajectory of the first voltage in the coordinate system; The second determining module is used to determine the magnitude relationship between the three-phase modulation waves of the locomotive inverter when an open-circuit fault occurs in a power transistor. The third determining module is used to determine a special region in the first voltage trajectory diagram based on the magnitude relationship between the three-phase modulation waves. Different magnitude relationships between the three-phase modulation waves correspond to different special regions. The calculation module is used to calculate and determine the second voltage trajectory diagram of the line voltage based on the special region. The second voltage trajectory diagram is a part of the first voltage trajectory diagram. The second voltage trajectory diagrams corresponding to different power transistors in the open circuit state are different. The second voltage trajectory diagram for calculating and determining the line voltage based on the special region includes: Calculate and determine the line voltage at - The third voltage trajectory in the coordinate system is: u ( t )and u ( t )for - Line voltage in sinusoidal form in a coordinate system; The - After the third voltage trajectory in the coordinate system is horizontally flipped, it is then rotated 60° clockwise to calculate the line voltage. '- 'The fourth voltage trajectory in the coordinate system:' ； Based on the fourth voltage trajectory, a second voltage trajectory diagram of the line voltage located in the special region is calculated and determined; The calculation and determination of the second voltage trajectory map based on the fourth voltage trajectory, which determines the line voltage in the special region, includes: Based on the fourth voltage trajectory, the fourth voltage trajectory diagram of the line voltage located in the special region is calculated as follows: '- In the coordinate system The first line segment on the axis; Convert the line segment to - The corresponding second line segment is obtained in the coordinate system. The second line segment is the second voltage trajectory of the line voltage in the special region. The second voltage trajectory is the one described in the coordinate system. - In a coordinate system, the line passes through the origin and has a slope of or line segments; Based on the second voltage trajectory and the corresponding special region, the second voltage trajectory diagram is obtained by dividing the first voltage trajectory diagram; The fourth determining module is used to determine the target power transistor in an open-circuit state based on the second voltage trajectory diagram.

6. An electronic device, characterized in that, include: At least one processor; as well as, A memory that is communicatively connected to the at least one processor; The memory stores instructions executable by the at least one processor, the instructions being configured to perform the power transistor open-circuit fault diagnosis method as described in any one of claims 1-4.

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