Power conversion device and degradation detection system

Abstract

This power conversion device (1) comprises: a component state detection unit (24) that detects, as a component state, a physical quantity representing the electrical characteristics of a component provided in the power conversion device (1); a storage unit (21) that stores first component state data, which represents a component state of the host power conversion device (1), and second component state data, which represents a component state of another power conversion device (1) and is transmitted from the other power conversion device (1) over a communication network (8) in a train, and stores a first deterioration curve created by using the first component state data and a second deterioration curve created by using the first and second pieces of component state data; a correction unit (22) that uses the second deterioration curve to correct the first deterioration curve; and a deterioration state detection unit (23) that uses the corrected first deterioration curve to detect a deterioration state of a component.

Description

Technical Field

[0001] The present disclosure relates to a power conversion device, a deterioration detection system, and a ground device used in a train formed by a plurality of railway vehicles.

Background Art

[0002] In a train, various electrical devices are mounted on railway vehicles and operated. Among these electrical devices, the power conversion device used for train propulsion control is an electrical device that has a great social impact due to failures.

[0003] Generally, for failures of electrical devices, there are three types of failures known as initial failures, accidental failures, and wear failures depending on the period during which the failures occur. Among these failures, an initial failure is a failure caused by manufacturing defects, and it is possible to extremely reduce the failure occurrence rate by appropriately performing quality control during manufacturing.

[0004] In Patent Document 1 below, a state-related value, which is a value related to the operating state of a motor system, is acquired in a plurality of motor systems, the acquired state-related values are compared among the plurality of motor systems, and if the difference in the state-related values is greater than a threshold value, it is diagnosed that an abnormality has occurred. The technique of Patent Document 1 is considered to be effective for detecting an abnormality of an accidental failure in which there is a large difference in state-related values between a motor system in which an abnormality has occurred and a motor system in which no abnormality has occurred.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Regarding the maintenance of power conversion equipment, the conventional maintenance method called TBM (Time Based Maintenance) was used, which involved replacing parts after a specific period of time. However, recently, there has been a shift towards a maintenance method called CBM (Condition Based Maintenance), which determines whether or not to replace parts based on data collected from electrical equipment. The key to adopting CBM is the ability to accurately detect abnormalities in the wear-out failure period.

[0007] As mentioned above, the technology described in Patent Document 1 is effective for detecting anomalies during the random failure phase. However, during the wear-out failure phase, wear-out failure progresses in all of the multiple systems, so the differences in state-related values ​​between the multiple systems are expected to be small. For this reason, it is considered difficult to accurately detect anomalies during the wear-out failure phase using the technology described in Patent Document 1.

[0008] This disclosure has been made in view of the above, and aims to provide a power conversion device that can accurately detect abnormalities in the device even during wear and tear failure periods. [Means for solving the problem]

[0009] To solve the above-mentioned problems and achieve the objective, the power converter according to this disclosure is used in a train composed of multiple railway cars. The power converter comprises a component state detection unit, a storage unit, a correction unit, and a degradation state detection unit. The component state detection unit detects physical quantities representing the electrical characteristics of components provided in the power converter as component states. The storage unit stores first component state data, which is data representing the component state of its own power converter, and second component state data, which is data representing the component state of other power converters and is transmitted from other power converters via a communication network within the train. The storage unit also stores a first degradation curve created using the first component state data and a second degradation curve created using the first and second component state data. The correction unit corrects the first degradation curve using the second degradation curve. The degradation state detection unit detects the degradation state of the components using the corrected first degradation curve. [Effects of the Invention]

[0010] The power conversion device described herein has the effect of being able to accurately detect abnormalities in the device even during wear and tear failure periods. [Brief explanation of the drawing]

[0011] [Figure 1] A diagram showing an example configuration of a power conversion device according to Embodiment 1. [Figure 2] This figure shows an example of the configuration of a control device provided in the power conversion device according to Embodiment 1. [Figure 3] A diagram illustrating the power conversion main circuit provided in the power conversion device according to Embodiment 1. [Figure 4] A schematic diagram showing the internal structure of a typical power semiconductor module. [Figure 5] A diagram illustrating the component state detection unit provided in the control device according to Embodiment 1. [Figure 6] This diagram shows the test results when thermal stress was applied to three identical power semiconductor modules. [Figure 7]This figure illustrates how the degradation curve described in Figure 6 may change depending on differences in the surrounding environment. [Figure 8] A diagram illustrating the correction process for the degradation curve in Embodiment 1. [Figure 9] Flowchart illustrating the operation of the control device, including the degradation curve correction process in Embodiment 1. [Figure 10] A diagram illustrating the heat flow when a power semiconductor module mounted on a cooler is in operation. [Figure 11] This figure shows an example of mounting a power semiconductor module, which is provided in a three-phase inverter of a power conversion device according to Embodiment 1, onto a cooler. [Figure 12] This figure shows an example configuration of the degradation detection system according to Embodiment 3. [Figure 13] A diagram showing an example configuration of the processing apparatus according to Embodiment 3. [Figure 14] This figure shows an example of the configuration of a ground device that works in conjunction with the deterioration detection system according to Embodiment 3. [Modes for carrying out the invention]

[0012] The power converter, degradation detection system, and ground equipment according to the embodiments of this disclosure will be described in detail below with reference to the attached drawings. In the following description, multiple devices and components of the same type will be indicated by subscripted reference numerals, but the subscripts will be omitted as appropriate when describing them without distinguishing between them. Furthermore, the following embodiments will be described using a power converter for train propulsion control as an example, but this is not intended to exclude its application to other uses. The power converter according to the embodiments can also be applied to power converters other than those for propulsion control, such as power converters for auxiliary power supplies that supply power to lighting, air conditioning, etc., of railway vehicles.

[0013] Embodiment 1. FIG. 1 is a diagram showing a configuration example of a power conversion device according to Embodiment 1. In FIG. 1, four power conversion devices 1a to 1d mounted on railway vehicles constituting a train are shown. The power conversion devices 1a to 1d are each provided with control devices 2a to 2d. The power conversion devices 1a to 1d are connected to a communication network 8 so that the control devices 2a to 2d can share data with each other. The communication network 8 is a means of data transmission and is not limited to a wired method. Also, in FIG. 1, four power conversion devices 1a to 1d are shown as an example, but it is not limited to this example. That is, the number of power conversion devices 1 may be 2 or 3, or may be 5 or more.

[0014] FIG. 2 is a diagram showing a configuration example of a control device provided in the power conversion device according to Embodiment 1. As shown in FIG. 2, the control device 2 includes a storage unit 21, a correction unit 22, a degradation state detection unit 23, and a component state detection unit 24. Details of the functions of each of these units will be described later.

[0015] The correction unit 22, the degradation state detection unit 23, and the component state detection unit 24 can be realized by a processing circuit having a processor and a memory. Also, instead of the processor and the memory, the correction unit 22, the degradation state detection unit 23, and the component state detection unit 24 may be realized by a dedicated processing circuit. As the dedicated processing circuit, an FPGA (Field Programmable Gate Array), an ASIC (Application Specific Integrated Circuit), a microcomputer, etc. are used. The storage unit 21 can be realized by a non-volatile or volatile semiconductor memory such as a RAM (Random Access Memory), a flash memory, an EPROM (Erasable Programmable ROM), an EEPROM (registered trademark) (Electrically EPROM), or a magnetic disk, an optical disk, a DVD (Digital Versatile Disc), etc.

[0016] Figure 3 is a diagram illustrating the power conversion main circuit provided in the power conversion device according to Embodiment 1. Figure 3 shows an example configuration of a power conversion main circuit 150 mounted on a railway vehicle 100. In Figure 3, the power conversion main circuit 150 comprises a converter 110, a filter capacitor 120, and a three-phase inverter 130. The railway vehicle 100 comprises a current collector 102, wheels 103, a transformer 106, and a propulsion motor 140. The transformer 106 is located on the input end side of the power conversion main circuit 150 and connected to the converter 110. The propulsion motor 140 is located on the output end side of the power conversion main circuit 150 and connected to the three-phase inverter 130. The three-phase inverter 130 converts DC power into AC power for the propulsion motor 140. An induction motor or a synchronous motor can be used as the propulsion motor 140.

[0017] One end of the primary winding of the transformer 106 is electrically connected to the overhead line 101 via the current collector 102, and the other end is electrically connected to the rail 104, which is at ground potential, via the wheel 103. The AC power supplied from the overhead line 101 is input to the converter 110 via the current collector 102 and the transformer 106.

[0018] Converter 110 comprises four switching elements UPC, VPC, UNC, and VNC connected in a single-phase bridge configuration. Converter 110 converts the input AC voltage to a desired DC voltage and outputs it by controlling the switching elements UPC, VPC, UNC, and VNC using PWM (Pulse Width Modulation).

[0019] A filter capacitor 120, which serves as a DC power supply, is connected in parallel to the output terminal of the converter 110. The filter capacitor 120 smooths the DC voltage input from the converter 110. A three-phase inverter 130 is connected to the output side of the filter capacitor 120.

[0020] The three-phase inverter 130 is equipped with three-phase bridge-connected switching elements UPI, VPI, WPI, UNI, VNI, and WNI. The three-phase inverter 130 converts the capacitor voltage smoothed by the filter capacitor 120 into a desired AC voltage by PWM control of the switching elements UPI, VPI, WPI, UNI, VNI, and WNI, and applies it to the propulsion motor 140.

[0021] In Figure 3, the switching elements UPC, VPC, UNC, VNC in the converter 110 and UPI, VPI, WPI, UNI, VNI, WNI in the three-phase inverter 130 are shown to be IGBTs (Insulated Gate Bipolar Transistors), but are not limited to this. These switching elements UPC, VPC, UNC, VNC, UPI, VPI, WPI, UNI, VNI, WNI may also be, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0022] Furthermore, while Figure 3 shows an example of the power converter 1 according to Embodiment 1 being applied to an electric vehicle with AC input, it can be similarly applied to electric vehicles with DC input, which are commonly used in subways and suburban electric vehicles. When applied to an electric vehicle with DC input, the configuration can be the same as in Figure 3, except that the transformer 106 and converter 110 are not required.

[0023] Furthermore, although Figure 3 shows both the converter 110 and the three-phase inverter 130 as having a two-level circuit configuration, the circuit configuration is not limited to this. Either one or both of the converter 110 and the three-phase inverter 130 may have a three-level circuit configuration. That is, the converter 110 may be a two-level converter and the three-phase inverter 130 may be a three-level three-phase inverter, or the converter 110 may be a three-level converter and the three-phase inverter 130 may be a two-level three-phase inverter, or the converter 110 may be a three-level converter and the three-phase inverter 130 may be a three-level three-phase inverter. Also, although Figure 3 shows the case where the AC power supplied from the overhead line 101 is single-phase, the AC power supplied from the overhead line 101 may be three-phase. If the AC power supplied from the overhead line 101 is three-phase, the converter 110 will have a three-phase circuit configuration.

[0024] Figure 4 is a schematic diagram showing the internal structure of a typical power semiconductor module. When the power semiconductor module 40 is for high power applications with high heat generation, it is common for it to be mounted on a metal base plate 41, as shown in Figure 4. An insulating substrate 42 is provided on the upper surface of the metal base plate 41, and multiple semiconductor chips 44 are arranged on the upper surface of the insulating substrate 42. In addition, a metal plate 43 is provided on the metal base plate 41, and external electrodes 47 are provided on the metal plate 43. Multiple wire bonds 45 are used for the electrical connection between the semiconductor chips 44 and the external electrodes 47. Metal wires such as gold, aluminum, and copper are used for the wire bonds 45.

[0025] When the power converter 1 operates and power is repeatedly supplied to the semiconductor chip 44, thermal stress gradually deteriorates the bonding state at the junction between the semiconductor chip 44 and the wire bond 45. As the deterioration progresses, the bonding between the semiconductor chip 44 and the wire bond 45 breaks. This phenomenon is called "lift-off". If this lift-off occurs in multiple wire bonds 45, the overall resistance of the junction increases, and the power converter 1 becomes unable to operate normally. Therefore, the power converter 1 according to Embodiment 1 performs a process to detect the deterioration state of the junction.

[0026] Figure 5 is a diagram illustrating the component state detection unit provided in the control device according to Embodiment 1. Figure 5 shows an equivalent circuit including the semiconductor chip 44, wire bond 45, and external electrode 47 described in Figure 4. Figure 5 also shows the component state detection unit 24 and the storage unit 21 provided in the control device 2. The component state detection unit 24 detects the electrical characteristics related to the junction state of the semiconductor chip 44 as the component state.

[0027] The semiconductor chip 44 includes an emitter auxiliary terminal 11, a gate terminal 12, an emitter electrode detection terminal 13, a collector electrode terminal 14, and an emitter electrode terminal 15. The emitter of the semiconductor chip 44 is connected to the emitter electrode terminal 15 via a plurality of wire bonds 45 and an external electrode 47. The collector of the semiconductor chip 44 is connected to the collector electrode terminal 14 via a plurality of wire bonds 46. Resistor Rt1 indicates the resistance at the junction between the emitter of the semiconductor chip 44 and the wire bond 45, and at the junction between the wire bond 45 and the external electrode 47. Resistor Rt2 indicates the resistance at the junction between the collector of the semiconductor chip 44 and the wire bond 46, and at the junction between the wire bond 46 and the collector electrode terminal 14.

[0028] The component status detection unit 24 is Emitter auxiliary terminal 11 and Emitter electrode detection terminal The component state detection unit 24 is electrically connected to 13 and detects the voltage across resistor Rt1. The component state detection unit 24 outputs the detected voltage value to the storage unit 21 as information about the component state. Here, "component state" refers to the bonding state of multiple wire bonds on the semiconductor chip. The voltage value detected by the component state detection unit 24 is stored in the storage unit 21.

[0029] The voltage value detected by the component state detection unit 24 is an example of a physical quantity that represents the electrical characteristics of the semiconductor chip 44. Another example of a physical quantity is the resistance value of the junctions in the semiconductor chip 44. If the current flowing through the semiconductor chip 44 is known, the resistance value of the junctions can be determined by a simple calculation from the detected voltage value. Therefore, by flowing a specified current through the semiconductor chip 44, detecting the voltage value at that time, and using the detected voltage value as the basis for the calculation... Rules The resistance value can be obtained by dividing by a constant value. This calculation may be performed by the component state detection unit 24 or by the control device 2 equipped with the storage unit 21.

[0030] Figure 6 shows the test results when thermal stress was applied to three identical power semiconductor modules. The waveforms shown in Figure 6 represent the voltage values ​​measured as a function of time when a specified current was repeatedly and intermittently passed through three identical power semiconductor modules 40. The characteristic curves of the three power semiconductor modules 40 are shown using three different line types (dashed line, dashed line, and solid line).

[0031] In Figure 6, the vertical axis represents the normalized state value, and the horizontal axis represents the normalization time. The normalized state value is the detected voltage value normalized to the initial voltage value, which is set to 1. The normalization time is the measurement time normalized to the time when the normalized state value reaches the specified value of "4.0 or higher".

[0032] In Figure 6, a normalized state value of 1.0 represents a brand-new power semiconductor module that has never had the specified current applied. In other words, a normalized state value of 1.0 means that the bonding state of the multiple wire bonds 45 on the semiconductor chip 44 is sound. Furthermore, a normalized state value of 4.0 or higher means that lift-off has occurred in almost all wire bonds 45 due to thermal stress, and the power semiconductor module 40 has deteriorated almost completely.

[0033] In this paper, the curve shown in Figure 6 is referred to as the "degradation curve." In the example shown in Figure 6, three identical power semiconductor modules were tested, but there was variation in the time it took for the normalized state value to reach 4.0 or higher, that is, the time it took for the power semiconductor module 40 to reach a nearly completely degraded state. However, when the horizontal axis is set to the normalized time, the degradation curves of these three power semiconductor modules 40 match well. This means that even if there is individual variation in the rate of degradation of the power semiconductor module 40, the individual variation in the change in the normalized state value as degradation progresses is small. Therefore, it means that the degradation state of the power semiconductor module 40 can be accurately detected from the normalized state value by using the degradation curve. As shown in Figure 6, the normalized state values ​​are almost identical up to the time until the normalized time reaches "0.7". Furthermore, beyond the normalized time of 0.7, there are some differences due to the characteristic that the normalized state value changes significantly even with a small change in time, but the degradation trend is consistent. Therefore, it is believed that by using a large number of degradation curves and statistically processing and averaging those degradation curves, the degradation state of the power semiconductor module 40 can be estimated with high accuracy.

[0034] Figure 7 illustrates how the degradation curve described in Figure 6 may change due to differences in the surrounding environment. Two examples of such differences in the surrounding environment of the power semiconductor module 40 are as follows: (1) The cooling performance of the coolers for the power semiconductor module 40 differs. (2) The positions on the cooler differ among the power semiconductor modules 40.

[0035] (1) However, if the cooling performance of the power semiconductor module 40's cooler is poor, thermal interference occurs between the multiple power semiconductor chips inside the power semiconductor module 40. In other words, the temperature of the central power semiconductor chip is higher than the temperature of the surrounding power semiconductor chips. Due to the large temperature difference, there is a large difference in the timing at which the junction between the semiconductor chip 44 and the wire bond 45 completely breaks, making it impossible for current to flow, among the multiple power semiconductor chips inside the power semiconductor module 40. Therefore, the degradation curve is as shown by the dashed line in Figure 7. In other words, changes in the normalized state value can be seen from a relatively early stage in the normalization time.

[0036] Furthermore, (1) if the cooling performance of the power semiconductor module 40's cooler is good, heat is well transferred to the cooler, whether it is a power semiconductor chip in the center of the power semiconductor module 40 or a power semiconductor chip around the periphery of the power semiconductor module 40. In other words, the temperature difference between the multiple power semiconductor chips inside the power semiconductor module 40 is small. Because the temperature difference is small, the time difference between the multiple power semiconductor chips inside the power semiconductor module 40 at which the junction between the semiconductor chip 44 and the wire bond 45 completely breaks and current flow becomes impossible is small. Therefore, the degradation curve is as shown by the solid line in Figure 7. In other words, the change in the normalized state value is observed relatively late in the normalization time.

[0037] Furthermore, (2) in the case of electrically parallel-connected power semiconductor modules 40, if the positions of the power semiconductor modules 40 on the cooler differ, there may be a large difference in cooling performance. Consequently, there is a large difference in the timing at which the junction between the semiconductor chip 44 and the wire bond 45 completely breaks, making it impossible for current to flow. Therefore, the degradation curve will be as shown by the dashed line in Figure 7. In other words, changes in the normalized state value can be observed from a relatively early stage of the normalization time.

[0038] As described above, the degradation curve may change due to differences in the surrounding environment of the power semiconductor module 40. To respond to changes in the degradation curve, the correction unit 22 provided in the control device 2 corrects the current degradation curve. Figure 8 is a diagram illustrating the degradation curve correction process in Embodiment 1. Figure 9 is a flowchart illustrating the operation of the control device, including the degradation curve correction process in Embodiment 1. In the explanation of Figure 9, the power converter 1 that performs the degradation curve correction process is referred to as "its own device," and power converters 1 other than its own device are referred to as "other devices."

[0039] In Figure 9, first, the degradation curve is stored in the memory unit during product manufacturing (step S11). In the case of long-life components, the degradation curve is obtained by artificial degradation testing of the component. In Figure 8, the degradation curve shown by the solid line corresponds to this. The component status detection unit 24 detects the component status of its own device during product operation (step S12). To elaborate, the component status detection unit 24 detects a physical quantity representing the electrical characteristics of the component installed in its own device as the component status. The control device 2 transmits the component status data, which is data representing the detected component status, to the communication network 8 within the train (step S13). The memory unit 21 of its own device stores both the component status data of its own device and the component status data of other devices, and the correction unit 22 of its own device corrects the degradation curve using both stored component status data (step S14). In Figure 8, the degradation curve shown by the dashed line corresponds to this. Statistical processing is used to correct the degradation curve. Furthermore, since the correction of the degradation curve uses not only the component status data of the device itself but also the component status data of other devices, the amount of data is large, and the accuracy of the degradation curve correction can be improved. The degradation state detection unit 23 uses the corrected degradation curve to detect the degradation state of the components of the device itself (step S15). Subsequently, each time the operating time of the device increases and the component status data increases, the process returns to step S12 and the degradation curve correction is repeated.

[0040] The correction process in step S14 will be further explained with reference to Figure 8. First, in step S11, the degradation curve is stored in the memory unit 21 during product manufacturing, and this degradation curve is a degradation curve using the entire data up to complete failure. On the other hand, since the component state data is obtained during the operation of the power converter, data up to a certain point in the degradation is obtained. In order to correct the entire degradation curve using the data up to a certain point in the degradation, the control device 2 is given the following judgment values ​​and performs the process. Specifically, the control device 2 is set with a first level A1 and a second level A2 which is greater than the first level A1 as judgment values ​​for determining the current level of the normalized state value. The correction unit 22 calculates the normalization time T1 at which the normalized state value reaches the first level A1 and the difference ΔT1 between the normalization time T1' at which the normalized state value reaches the second level A2 and the normalization time T1 in the first degradation curve shown by the solid line. Furthermore, the correction unit 22 calculates the first degradation ratio ΔT1 / T1, which is the ratio of the difference ΔT1 to the normalization time T1. Similarly, the correction unit 22 determines a second degradation ratio ΔT2 / T2 based on the normalization time T2 at which the normalized state value reaches the first level A1, and the difference ΔT2 between the normalization time T2' at which the normalized state value reaches the second level A2 and the normalization time T2, in the second degradation curve shown by the dashed line.

[0041] Figure 8 shows an example where the first degradation ratio ΔT1 / T1 is smaller than the second degradation ratio ΔT2 / T2. The second degradation ratio ΔT2 / T2 is a value calculated based on component status data that includes not only the component status data of the device itself but also the component status data of other devices, and is a value that reflects the actual usage environment, i.e., the real situation. For this reason, the correction unit 22 uses the second degradation ratio ΔT2 / T2 to correct the first degradation curve, which is the device's own degradation curve.

[0042] In the above explanation, the degradation curve shown by the solid line corresponds to the first degradation curve, and the degradation curve shown by the dashed line corresponds to the second degradation curve. However, the opposite pattern is also possible. If the conditions of the operating environment are not as severe as assumed, the degradation curve shown by the dashed line may correspond to the first degradation curve, and the degradation curve shown by the solid line may correspond to the second degradation curve. However, in either case, the first degradation curve will be corrected based on values ​​calculated from a large amount of component condition data, including not only the first component condition data but also the second component condition data. Therefore, in either case, the degradation curve will be corrected to match the actual situation, making it possible to improve the accuracy of component condition degradation judgment.

[0043] As described above, the power converter according to Embodiment 1 is a power converter used for propulsion control of a train composed of multiple railway vehicles, and comprises a component state detection unit, a storage unit, a correction unit, and a degradation state detection unit. The component state detection unit detects physical quantities representing the electrical characteristics of components provided in the power converter as component states. The storage unit stores first component state data, which is data representing the component state of its own power converter, and second component state data, which is data representing the component state of other power converters and is transmitted from other power converters via a communication network within the train. The storage unit also stores a first degradation curve created using the first component state data and a second degradation curve created using the first and second component state data. The correction unit corrects the first degradation curve using the second degradation curve. The degradation state detection unit detects the degradation state of the components using the corrected first degradation curve. In the power converter configured in this way, the second degradation curve is created based on second component status data transmitted from multiple power converters other than its own, and is therefore a correction curve that reflects the actual situation. For this reason, the first degradation curve, which has been corrected using the second degradation curve, is also corrected to a correction curve that reflects the actual situation. Consequently, by using the power converter according to Embodiment 1, even if the degradation determination timing is during the wear failure period, the degradation state of the components can be determined with high accuracy, making it possible to accurately detect abnormalities in the power converter. Furthermore, in the power converter according to Embodiment 1, since the first degradation curve is corrected to a correction curve that reflects the actual situation, it is possible to accurately detect abnormalities in the power converter even if the degradation determination timing is during the random failure period.

[0044] Furthermore, when the power conversion device according to Embodiment 1 includes a three-phase inverter that converts DC power into AC power for a propulsion motor, the first and second component status data may represent the status of components provided in the three-phase inverter. In this case, the second component status data may be component status data transmitted from multiple other power conversion devices located within the same vehicle of the railway cars constituting the train, or it may be component status data transmitted from multiple other power conversion devices located within the same vehicle and in different vehicles of the railway cars constituting the train.

[0045] In the case where the power converter according to Embodiment 1 is a power converter mounted on an electric vehicle with AC input and includes a converter that converts AC power to DC power, the first and second component status data may be data representing the component status of components provided in the converter. In this case, the second component status data may be component status data transmitted from multiple other power converters located within the same vehicle of the railway cars constituting the train, or it may be component status data transmitted from multiple other power converters located within the same vehicle and in different vehicles of the railway cars constituting the train.

[0046] An example of a component detected by the component status detection unit is a power semiconductor module provided in a three-phase inverter or converter. In this example, the component status detection unit detects the electrical resistance of the power semiconductor module as the bonding state of multiple wire bonds on the semiconductor chip. Another example of a component detected by the component status detection unit is a filter capacitor provided in a power conversion main circuit. In this example, the component status detection unit can detect the charging time and discharging time of the filter capacitor as component status data. By detecting the charging time and discharging time of the filter capacitor as component status data, it becomes possible to objectively determine the degree of capacitance degradation of the filter capacitor in one's own power conversion device by comparing it with the filter capacitor in other power conversion devices.

[0047] Embodiment 2. Embodiment 1 described how the degradation curve of the power semiconductor module 40 changes due to differences in the surrounding environment, and also mentioned that the cooling performance of the cooler and the position on the cooler where the power semiconductor module 40 is mounted are related to the change in the degradation curve due to differences in the surrounding environment. Embodiment 2 describes a control method that takes these differences in the surrounding environment into account.

[0048] Figure 10 illustrates the heat flow when a power semiconductor module mounted on a cooler is in operation. When the power semiconductor module 40 is a high-power module that generates a large amount of heat, it is often mounted on a cooler 48, as shown in Figure 10. The power semiconductor module 40 contains multiple semiconductor chips 44, and the temperature rise of the semiconductor chips 44 due to heat generation depends on the cooling performance of the cooler 48. If the cooling performance of the cooler 48 is good, the heat generated by the semiconductor chips 44 moves in the direction of the cooler 48, which in the configuration of Figure 10 is downward. In this case, thermal interference between the semiconductor chips 44 is small, and the temperature difference between the semiconductor chips 44 is small. As a result, the variation in thermal stress experienced by the semiconductor chips 44 is small.

[0049] In contrast, if the cooling performance of the cooler 48 is poor, the heat generated by the semiconductor chip will move not only downwards in Figure 10, but also laterally. In this case, thermal interference between the semiconductor chips 44 will increase, and the temperature difference between the semiconductor chips 44 will also increase. As a result, the variation in thermal stress experienced by the semiconductor chips 44 will increase.

[0050] As described above, the actual cooling performance of the cooler 48 differs from the cooling performance of the cooler 48 assumed during the design phase. Therefore, a difference will arise between the degradation curve assumed during the design phase and the actual degradation curve.

[0051] Figure 11 shows an example of mounting a power semiconductor module, which is provided in a three-phase inverter of a power converter according to Embodiment 1, on a cooler. When the power converter 1 according to Embodiment 1 is a power converter for a railway vehicle, the power semiconductor module 49 is placed on a cooler 48 that utilizes cooling air from the running airflow. The cooler 48 is a self-cooling type that utilizes running airflow, and the cooling air passes through the cooler 48 as the railway vehicle moves.

[0052] The three-phase inverter 130 is equipped with nine power semiconductor modules 49. Each power semiconductor module 49 is a two-element module, containing two switching elements that constitute each phase leg within a single module. In Figure 11, the nine power semiconductor modules 49u1~49u3, 49v1~49v3, and 49w1~49w3 are arranged in a 3x3 square grid on the first surface 48a, which is the module mounting surface of the cooler 48. In other words, the nine power semiconductor modules 49u1~49u3, 49v1~49v3, and 49w1~49w3 are arranged in columns of three along a second direction perpendicular to the first direction in which the cooling air flows on the first surface 48a. When the columns are numbered 1, 2, and 3 from left to right along the first direction, power semiconductor modules 49u1 to 49u3 are arranged in the 1st column, power semiconductor modules 49v1 to 49v3 are arranged in the 2nd column, and power semiconductor modules 49w1 to 49w3 are arranged in the 3rd column.

[0053] Power semiconductor modules 49u1 to 49u3 constitute the U-phase leg, power semiconductor modules 49v1 to 49v3 constitute the V-phase leg, and power semiconductor modules 49w1 to 49w3 constitute the W-phase leg. In other words, each phase leg is composed of three 2-element modules in parallel.

[0054] Since railway vehicles travel both forward and backward without changing direction, the direction of the cooling air is reversed between the forward and backward journeys. Consequently, the power semiconductor modules 49 located in the first and third rows may be either upstream or downstream of the cooling air. As a result, the power semiconductor modules 49 located in the first and third rows experience a large temperature difference between the upstream and downstream sides. In contrast, the power semiconductor modules 49 located in the second row are always positioned in the second row on both the upstream and downstream sides, so the temperature difference due to the difference in direction of travel is small.

[0055] Furthermore, the power semiconductor modules 49 arranged around the periphery of the square grid receive less thermal interference from other power semiconductor modules 49, resulting in a lower average temperature. In contrast, the power semiconductor modules 49 mounted in the center of the square grid receive more thermal interference from other power semiconductor modules 49, resulting in a higher average temperature.

[0056] As described above, when the power converter 1 is a self-cooling power converter that utilizes the airflow from the vehicle, the temperature difference between the power semiconductor modules 49 and the average temperature are different, so in Embodiment 2, management is performed as follows.

[0057] One first power semiconductor module, positioned at the center of the nine power semiconductor modules, and the eight second power semiconductor modules, positioned around the first power semiconductor module, are distinguished as power semiconductor modules placed in different environments and managed as separate component state data. By managing them in this way, statistical processing can be performed between component state data with similar degradation trends, thereby improving the accuracy of degradation curve correction.

[0058] Alternatively, the six power semiconductor modules located in the first and third columns and the three power semiconductor modules located in the second column can be distinguished as power semiconductor modules placed in different environments and managed as different component status data. Even with this management, statistical processing is performed between component status data with similar degradation trends, which improves the accuracy of degradation curve correction.

[0059] In Figure 11, the example shows a case where the number of power semiconductor modules 49 in the three-phase inverter 130 is 9, but it may be other than 9. In other examples as well, the accuracy of correcting the degradation curve can be improved by distinguishing and managing component condition data with similar degradation trends so that statistical processing is performed between them.

[0060] As described above, the power converter according to Embodiment 2 distinguishes and manages component state data with similar degradation trends so that statistical processing is performed between them, thereby improving the accuracy of degradation curve correction.

[0061] Embodiment 3. Figure 12 shows an example of the configuration of the degradation detection system according to Embodiment 3. The degradation detection system 80 according to Embodiment 3 consists of power converters 3a to 3d equipped with control devices 4a to 4d, and a processing unit 50. In Figure 12, the same or equivalent components as in Figure 1 are denoted by the same reference numerals. For the same or equivalent components, redundant explanations are omitted.

[0062] The processing unit 50 is connected to a communication network 8 so that it can share data with power converters 3a to 3d. The processing unit 50 is also configured to communicate with a ground device 60, which will be described later. The processing unit 50 has the functions of the storage unit 21, correction unit 22, and degradation state detection unit 23 of the control device 2 described in Embodiment 1. For this reason, the control device 4 according to Embodiment 3 does not need to have the functions of the correction unit 22 and the degradation state detection unit 23. In addition, in the control device 4 according to Embodiment 3, the storage unit 21 stores the component status data detected by the component status detection unit 24 and transmits it to the processing unit at any time.

[0063] Figure 13 shows an example of the configuration of the processing unit according to Embodiment 3. The processing unit 50 manages component status data that represents the status of the components of the power converter 3 and is transmitted from the power converter 3 through the communication network 8 inside the train. To realize this function, the processing unit 50 includes a storage unit 51, a correction unit 52, and a deterioration state detection unit 53, as shown in Figure 13.

[0064] The storage unit 51 stores first component status data, which is data representing the component status of the components in the first power converter, and second component status data, which is data representing the component status of the components in the second power converter. The first power converter means any one of the power converters 3a to 3d, and the second power converter means a power converter other than the first power converter. The storage unit 51 also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data. The correction unit 52 is the first 2 Using the degradation curve, 1 The deterioration curve is corrected. The deterioration state detection unit 53 , supplement Corrected 1 The degradation state of the component is detected using the degradation curve.

[0065] The storage unit 51 can be implemented using non-volatile or volatile semiconductor memory such as RAM, flash memory, EPROM, or EEPROM (registered trademark), or magnetic disks, optical disks, DVDs, etc. The correction unit 52 and the degradation state detection unit 53 can be implemented using a processor such as a CPU (Central Processing Unit). The processor executes a program in which processing is described. The storage unit 51 also stores the programs that the correction unit 52 and the degradation state detection unit 53 should execute, as well as any necessary data obtained during the processing. The storage unit 51 is also used as a temporary storage area for programs. Note that the configuration in Figure 13 is just one example, and the configuration of the device is not limited to the example in Figure 13.

[0066] Furthermore, the functions of the processing unit 50 described above may be built inside a train information management device, which is a device that manages train information transmitted within the train. Existing train information management devices have communication functions with the power converter 3 and with the ground. Therefore, using an existing train information management device can reduce the cost of system construction.

[0067] Figure 14 shows an example of the configuration of a ground device that works in conjunction with the deterioration detection system according to Embodiment 3. The ground device 60 includes a receiving unit 61, a storage unit 62, and an output unit 63.

[0068] The receiving unit 61 receives detection results from the processing unit 50 of the deterioration detection system 80. The receiving unit 61 may also receive information regarding the deterioration curve if necessary. The storage unit 62 stores the received detection results. When storing the detection results, the storage unit 62 stores them in correspondence with identification numbers for identifying the vehicle and parts. The output unit 63 consists of a display, liquid crystal display panel, printer, etc., and displays various screens to the user of the computer system and provides necessary information on paper. Note that the configuration in Figure 14 is an example, and the configuration of the device is not limited to the example in Figure 14.

[0069] As described above, the degradation detection system according to Embodiment 3 comprises a power converter used for train propulsion control, and a processing unit that manages component status data representing the state of the components of the power converter, which is transmitted from the power converter through a communication network within the train. Each power converter present in the train is equipped with a component status detector that detects the state of the components installed in the power converter. The processing unit comprises a storage unit, a correction unit, and a degradation state detection unit. The storage unit stores first component status data, which is data representing the state of the components in the first power converter, and second component status data, which is data representing the state of the components of the second power converter, which is a power converter other than the first power converter. The storage unit also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data. The correction unit corrects the first degradation curve using the second degradation curve. The degradation state detection unit detects the degradation state of the components in the first power converter using the corrected first degradation curve. The processing unit can perform the component degradation state detection process for all power converters by replacing the first power converter with other power converters and repeating the above process. The degradation detection system according to Embodiment 3 allows the processing unit to be configured as a computer system, and the processing unit can centrally manage the first and second component status data, thus enabling faster processing compared to Embodiment 1.

[0070] In Embodiment 3, the first and second component status data are component status data transmitted from multiple power converters located within the vehicles of the railway cars constituting the train. However, they may also be component status data transmitted from multiple other power converters located within the vehicles of other trains traveling on the same line as the train. This increases the number of first and second component status data, thereby improving the accuracy of the degradation curve correction. As a result, the accuracy of component status degradation determination can also be improved.

[0071] The configurations shown in the above embodiments are merely examples, and it is possible to combine them with other known technologies, combine different embodiments, and omit or modify parts of the configuration without departing from the gist of the invention. The various aspects of this disclosure are summarized below as an appendix. [Note 1] In a power converter used in a train composed of multiple railway cars, A component state detection unit detects a physical quantity representing the electrical characteristics of a component in the power converter as the component state, A storage unit that stores first component status data, which is data representing the component status of its own power converter, and second component status data, which is data representing the component status of another power converter and is transmitted from the other power converter via the train's communication network, and also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data, A correction unit that corrects the first degradation curve using the second degradation curve, A deterioration state detection unit that detects the deterioration state of the component using the corrected first deterioration curve, A power conversion device characterized by being equipped with the following features. [Note 2] The power conversion device includes a three-phase inverter that converts DC power into AC power for the propulsion motor. The first and second component status data are data representing the status of components provided in the three-phase inverter. The second component status data is transmitted from multiple other power converters located within the same vehicle of the railway car constituting the train. The power conversion device described in Appendix 1, characterized by the features described herein. [Note 3] The power conversion device includes a three-phase inverter that converts DC power into AC power for the propulsion motor. The first and second component status data are data representing the status of components provided in the three-phase inverter. The second component status data is transmitted from multiple other power converters located within the same vehicle and in different vehicles of the railway cars that make up the train. The power conversion device described in Appendix 1, characterized by the features described herein. [Note 4] The power conversion device comprises a converter that converts AC power to DC power, and a three-phase inverter that converts the DC power to AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the converter. The second component status data is transmitted from multiple other power converters located within the same vehicle of the railway car constituting the train. The power conversion device described in Appendix 1, characterized by the features described herein. [Note 5] The power conversion device comprises a converter that converts AC power to DC power, and a three-phase inverter that converts the DC power to AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the converter. The second component status data is transmitted from multiple other power converters located within the same vehicle and in different vehicles of the railway cars that make up the train. The power conversion device described in Appendix 1, characterized by the features described herein. [Note 6] The power conversion device comprises a power semiconductor module in which a semiconductor chip and an external electrode are joined by a plurality of wire bonds. The component state detection unit detects the electrical resistance of the power semiconductor module as the bonding state of the plurality of wire bonds in the semiconductor chip. A power conversion device as described in any one of the appendices 2 to 5, characterized by the above. [Note 7] The three-phase inverter comprises nine power semiconductor modules, each in which a semiconductor chip and external electrodes are joined by multiple wire bonds. The power converter includes a cooler for cooling nine of the power semiconductor modules. The nine power semiconductor modules are arranged in a 3x3 square grid on the first surface, which is the module mounting surface of the cooler. One first power semiconductor module located at the center of the nine power semiconductor modules and eight second power semiconductor modules located around the first power semiconductor module are distinguished as power semiconductor modules placed in different environments and are managed as different component status data. The power conversion device described in Appendix 6, characterized by the features described herein. [Note 8] The three-phase inverter comprises nine power semiconductor modules, each in which a semiconductor chip and external electrodes are joined by multiple wire bonds. The power converter includes a cooler for cooling nine of the power semiconductor modules. The nine power semiconductor modules are arranged in rows of three along a second direction perpendicular to the first direction in which cooling air flows on the module mounting surface of the cooler. When the columns are arranged in order along the first direction, they are designated as the first, second, and third columns, The six power semiconductor modules arranged in the first and third columns and the three power semiconductor modules arranged in the second column are distinguished as power semiconductor modules placed in different environments and are managed as different component status data. The power conversion device described in Appendix 6, characterized by the features described herein. [Note 9] The first and second degradation curves are curves that represent the relationship between a normalized state value, which is obtained by normalizing the value of the physical quantity of the component at the time of detection to the value of the physical quantity of the component in its initial state as 1, and a normalized time, which is obtained by normalizing the usage time of the component to the time until the physical quantity of the component reaches a specified value. A power conversion device as described in any one of the appendices 6 to 8, characterized by the above. [Note 10] Each of the aforementioned power converters includes a display unit configured to display the detection results from the deterioration state detection unit. The power conversion device described in Appendix 9, characterized by the features described herein. [Note 11] A deterioration detection system comprising a power converter used in a train composed of multiple railway cars, and a processing unit that manages component status data representing the status of components of the power converter transmitted from the power converter via a communication network within the train, wherein the deterioration state of the components is detected based on the component status data, Each of the power converters located within the train is equipped with a component state detector that detects the state of the components provided in the power converter. The aforementioned processing apparatus is A storage unit that stores first component status data, which is data representing the component status of the components in the first power converter, and second component status data, which is data representing the component status of the components of a second power converter, which is a power converter other than the first power converter, and also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data, A correction unit that corrects the first degradation curve using the second degradation curve, A deterioration state detection unit that detects the deterioration state of components in the first power converter using the corrected first deterioration curve, A degradation detection system characterized by having the following features. [Note 12] The first and second component status data are also transmitted from multiple other power converters located within the vehicles of other trains traveling on the same line as the aforementioned train. The deterioration detection system described in Appendix 11, characterized by the features described herein. [Note 13] A ground device that works in conjunction with the deterioration detection system described in Appendix 11 or 12, A receiving unit that receives information regarding the component status of the power converter from the degradation detection system, A storage unit that stores information about the status of the component received, An output unit that outputs or displays the information stored in the storage unit, A ground device characterized by being equipped with the following features. [Explanation of symbols]

[0072] 1,1a~1d,3,3a~3d Power converter, 2,2a~2d,4,4a~4d Control device, 8 Communication network, 11 Emitter auxiliary terminal, 12 Gate terminal, 13 Emitter electrode detection terminal, 14 Collector electrode terminal, 15 Emitter electrode terminal, 21,51,62 Memory unit, 22,52 Correction unit, 23,53 Degradation state detection unit, 24 Component state detection unit, 40,49,49u1~49u3,49v1~49v3,49w1~49w3 Power semiconductor module, 41 Metal base plate, 42 Insulating substrate, 43 Metal plate, 44 Semiconductor chip, 45,46 Wire bond, 47 External electrode, 48 Cooler, 48a First surface, 50 Processing unit, 60 Ground equipment, 61 Receiving unit, 63 Output unit, 80 Degradation detection system, 100 Railway vehicles, 101 Overhead lines, 102 Current collectors, 103 Wheels, 104 Rails, 106 Transformers, 110 Converters, 120 Filter capacitors, 130 Three-phase inverters, 140 Propulsion motors, 150 Power conversion main circuits, UPC, VPC, UNC, VNC, UPI, VPI, WPI, UNI, VNI, WNI switching elements.

Claims

1. In a power converter used in a train composed of multiple railway cars, A component state detection unit detects a physical quantity representing the electrical characteristics of a component in the power converter as the component state, A storage unit that stores first component status data, which is data representing the component status of its own power converter, and second component status data, which is data representing the component status of another power converter and is transmitted from the other power converter via the train's communication network, and also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data, A correction unit that corrects the first degradation curve using the second degradation curve, A deterioration state detection unit that detects the deterioration state of the component using the corrected first deterioration curve, Equipped with, The first and second degradation curves are curves that represent the relationship between a normalized state value, which is obtained by normalizing the value of the physical quantity of the component at the time of detection to the value of the physical quantity of the component in its initial state as 1, and a normalized time, which is obtained by normalizing the usage time of the component to the time until the physical quantity of the component reaches a specified value. A power conversion device characterized by the following features.

2. The power conversion device includes a three-phase inverter that converts DC power into AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the three-phase inverter. The second component status data is transmitted from multiple other power converters located within the same vehicle of the railway car constituting the train. The power conversion device according to feature 1.

3. The power conversion device includes a three-phase inverter that converts DC power into AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the three-phase inverter. The second component status data is transmitted from multiple other power converters located within the same vehicle and in different vehicles of the railway cars that make up the train. The power conversion device according to feature 1.

4. The power conversion device comprises a converter that converts AC power to DC power, and a three-phase inverter that converts the DC power to AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the converter. The second component status data is transmitted from multiple other power converters located within the same vehicle of the railway car constituting the train. The power conversion device according to feature 1.

5. The power conversion device comprises a converter that converts AC power to DC power, and a three-phase inverter that converts the DC power to AC power for the propulsion motor. The first and second component status data are data representing the component status of the components provided in the converter. The second component status data is transmitted from multiple other power converters located within the same vehicle and in different vehicles of the railway cars that make up the train. The power conversion device according to feature 1.

6. The power conversion device comprises a power semiconductor module in which a semiconductor chip and an external electrode are joined by a plurality of wire bonds. The component state detection unit detects the electrical resistance of the power semiconductor module as the bonding state of the plurality of wire bonds in the semiconductor chip. The power conversion device according to feature 2.

7. The three-phase inverter comprises nine power semiconductor modules, each in which a semiconductor chip and an external electrode are joined by multiple wire bonds. The power converter includes a cooler for cooling nine of the power semiconductor modules. The nine power semiconductor modules are arranged in a 3x3 square grid on the first surface, which is the module mounting surface of the cooler. One first power semiconductor module positioned at the center of the nine power semiconductor modules and eight second power semiconductor modules positioned around the first power semiconductor module are distinguished as power semiconductor modules placed in different environments and are managed as different component status data. The power conversion device according to feature 6.

8. The three-phase inverter comprises nine power semiconductor modules, each in which a semiconductor chip and an external electrode are joined by multiple wire bonds. The power converter includes a cooler for cooling nine of the power semiconductor modules. The nine power semiconductor modules are arranged in rows of three along a second direction perpendicular to the first direction in which cooling air flows on the module mounting surface of the cooler. When the rows are arranged in order along the first direction, they are designated as the first, second, and third columns, The six power semiconductor modules arranged in the first and third columns and the three power semiconductor modules arranged in the second column are distinguished as power semiconductor modules placed in different environments and are managed as different component status data. The power conversion device according to feature 6.

9. Each of the aforementioned power converters includes a display unit configured to display the detection results from the deterioration state detection unit. The power conversion device according to feature 8.

10. A deterioration detection system comprising a power converter used in a train composed of multiple railway cars, and a processing unit that manages component status data representing the status of components of the power converter transmitted from the power converter via a communication network within the train, wherein the deterioration state of the components is detected based on the component status data, Each of the power converters located within the train is equipped with a component state detector that detects the state of the components provided in the power converter. The aforementioned processing apparatus is A storage unit that stores first component status data, which is data representing the component status of the component in the first power converter, and second component status data, which is data representing the component status of the component in a second power converter, which is a power converter other than the first power converter, and also stores a first degradation curve created using the first component status data and a second degradation curve created using the first and second component status data, A correction unit that corrects the first degradation curve using the second degradation curve, A deterioration state detection unit that detects the deterioration state of components in the first power converter using the corrected first deterioration curve, Equipped with, The first and second degradation curves are curves that represent the relationship between a normalized state value, which is obtained by normalizing the value of the physical quantity of the component at the time of detection to the value of the physical quantity of the component in its initial state as 1, and a normalized time, which is obtained by normalizing the usage time of the component to the time until the physical quantity of the component reaches a specified value. A degradation detection system characterized by the following features.

11. The first and second component status data are also transmitted from multiple other power converters located within the vehicles of other trains traveling on the same route as the aforementioned train. The deterioration detection system according to feature 10.

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