JP4925763B2 - Semiconductor module - Google Patents

Description

  The present invention relates to a semiconductor module, and more particularly to a semiconductor module having a function of monitoring partial discharge of a load.

For example, Japanese Patent Laying-Open No. 2003-274667 (Patent Document 1) discloses a power module for a three-phase inverter provided with a circuit for detecting a winding current of a three-phase motor. In this power module, a sense IGBT in which an emitter is divided into a main emitter and a sense emitter is used for an IGBT (Insulated Gate Bipolar Transistor) constituting the lower arm of a three-phase full-bridge circuit. A shunt resistor for current / voltage conversion is connected between the sense emitter and the ground terminal. When current is output from the sense emitter, a voltage is generated across the shunt resistor. Based on this voltage, the magnitude of the main current or the magnitude of the regenerative current is detected.
JP 2003-274667 A

  If a minute gap or the like is present in an insulator included in a load such as a rotating machine, an electric field concentrates on the portion and a weak discharge is generated. Such discharge is generally called “partial discharge”. When the partial discharge occurs, the insulator is liable to deteriorate. Therefore, dielectric breakdown may occur in the partial discharge generation portion during long-time use. There are various places where the partial discharge occurs in the rotating machine. For example, the partial discharge may occur between the turns of the stator winding, between the single fixed terminals, the end of the winding, or the like.

  When partial discharge occurs, a weak high-frequency component is superimposed on the current flowing through the load. As described above, the conventional semiconductor module also has a function of detecting the current flowing through the load. As disclosed in Japanese Patent Laid-Open No. 2003-274667 (Patent Document 1), the conventional semiconductor module has a resistance connected to the sense emitter. Measure the resulting voltage. However, although this method is excellent for measuring large currents during normal operation of the load or during ground faults, sufficient detection sensitivity cannot be obtained for measurement of weak high-frequency currents such as partial discharge measurement. .

  On the other hand, in order to detect whether a partial discharge is generated in the rotating machine, a method of measuring a high frequency component of a current using a high frequency amplifier or a method of detecting a radio wave generated by the partial discharge by an antenna is used. . However, when implementing these methods, it is necessary to provide a device for detecting partial discharge in or near the rotating machine.

  An object of the present invention is to provide a semiconductor module capable of detecting minute high-frequency noise superimposed on a current output from a semiconductor switching element.

  In summary, the present invention is a semiconductor module comprising a semiconductor switching element and a detector. The semiconductor switching element has a main cell unit that outputs a main current and a sense cell unit that outputs a sense current proportional to the main current. The detector detects whether or not a predetermined frequency component having a frequency higher than the switching frequency of the semiconductor switching element is included in the sense current.

  According to the present invention, minute high frequency noise superimposed on the main current output from the semiconductor switching element can be detected by the sense current.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Embodiment 1]
FIG. 1 is a diagram illustrating a configuration example of the semiconductor module according to the first embodiment.

  Referring to FIG. 1, an IPM (intelligent power module) 100 corresponds to the semiconductor module of the present invention. The IPM 100 drives a three-phase motor 102 that is a load.

  IPM 100 includes terminals T 1, T 2, TU, TV, TW, U-phase arm 1, V-phase arm 2, and W-phase arm 3.

A potential VCC is applied to the terminal T1, and a ground potential is applied to the terminal T2.
U-phase arm 1 includes IGBT elements Q1 and Q2 connected in series between terminals T1 and T2, diodes D1 and D2 connected in reverse parallel to IGBT elements Q1 and Q2, respectively, 12 and drive circuits 21 and 22 for driving IGBT elements Q1 and Q2, respectively.

  Each of IGBT elements Q1 and Q2 is a semiconductor switching element having a main cell portion and a sense cell portion. The emitters of IGBT elements Q1 and Q2 are divided into two parts: an emitter (main emitter) in the main cell portion and an emitter (sense emitter) in the sense cell portion. The ratio of the main current flowing out from the main emitter and the sense current flowing out from the sense emitter is set to 1000: 1, for example.

  In general, an IGBT element is composed of a large number of unit cells formed on a semiconductor chip. By appropriately setting the number of cells in the main cell portion and the number of cells in the sense cell portion, the current ratio as described above can be set.

  The collector of IGBT element Q1 is connected to terminal T1, the gate of IGBT element Q1 is connected to drive circuit 21, and the main emitter of IGBT element Q1 is connected to terminal TU. The collector of IGBT element Q2 is connected to terminal TU, the gate of IGBT element Q2 is connected to drive circuit 22, and the main emitter of IGBT element Q2 is connected to terminal T2.

  Monitoring unit 11 is provided between the sense emitter of IGBT element Q1 and terminal TU. The monitoring unit 12 is provided between the sense emitter of the IGBT element Q2 and the terminal T2.

  Drive circuits 21 and 22 send signals having specific frequencies to IGBT elements Q1 and Q2, respectively. IGBT elements Q1, Q2 are repeatedly turned on / off at the frequency (switching frequency) of the signal. When partial discharge occurs in the three-phase motor 102, a frequency component (high frequency noise) having a frequency higher than the switching frequency is superimposed on the main current flowing in the three-phase motor 102.

  The sense current output from the sense emitters of IGBT elements Q1, Q2 is proportional to the main current. Therefore, when high-frequency noise is superimposed on the main current, a high-frequency component having a frequency higher than the switching frequency of IGBT elements Q1 and Q2 is included in the sense current.

  Monitoring units 11 and 12 monitor whether or not the above-described high frequency components are included in the sense currents output from IGBT elements Q1 and Q2, respectively. The monitoring units 11 and 12 output the monitoring results as signals S1 and S2, respectively.

  The signals S1 and S2 are sent to the control device 104 provided outside the IPM 100. The control device 104 performs various processes according to the signals S1 and S2. For example, the control device 104 controls the drive circuits 21 and 22 and determines whether or not the three-phase motor 102 needs to be replaced.

  V-phase arm 2 and W-phase arm 3 have the same configuration as U-phase arm 1. Therefore, detailed description of the configuration of V-phase arm 2 and the configuration of W-phase arm 3 will not be repeated hereinafter.

  Next, the configuration of the IGBT element Q1 and the monitoring unit 11 will be described in more detail. The configuration of the IGBT element Q2 and the monitoring unit 12 is a configuration in which the IGBT element Q1 is replaced with the IGBT element Q2 and the monitoring unit 11 is replaced with the monitoring unit 12 in the following drawings.

FIG. 2 is a diagram showing the configuration of the IGBT element Q1 and the monitoring unit 11 of FIG.
Referring to FIG. 2, IGBT element Q <b> 1 includes a main cell portion 31 and a sense cell portion 32. The main cell portion 31 has a pad P1 corresponding to the main emitter terminal. The sense cell unit 32 has a pad P2 corresponding to the sense emitter terminal.

  FIG. 2 schematically shows the surface of the IGBT element Q1. The entire surface of IGBT element Q1 is covered with an emitter electrode. Although not shown, the gate electrode of the IGBT element Q1 is provided below the emitter electrode. The collector electrode of IGBT element Q1 is provided on the back surface (not shown) of IGBT element Q1.

  When the three-phase motor 102 shown in FIG. 1 operates, the main current I1 is output from the main cell unit 31 via the pad P1. A sense current I proportional to the main current I1 is output from the sense cell unit 32 via the pad P2.

  The monitoring unit 11 includes an inductor (coil) L1 and a voltage detection unit 41. One end of inductor L1 is coupled to pad P2. Both the other end of inductor L1 and pad P1 are coupled to terminal TU.

  When a sense current I flows from one end of the inductor L1 to the other end, an electromotive voltage is generated at both ends of the inductor. If this electromotive voltage is V1, and the inductance component of the inductor L1 is L, the voltage V1 is V1 = L × (dI / dt). That is, the inductor L1 serves to differentiate the sense current I with respect to time. For example, the voltage detector 41 detects the peak value of the voltage V1 and outputs information on the peak value of the voltage V1 as a monitoring result (signal S1).

  In the conventional IPM, a resistor is connected between the pad P2 and the terminal TU. When the sense current I is output from the pad P2, a voltage is generated between both terminals of the resistor. Based on this voltage, the magnitude of the main current I1 is detected.

  Since the sense current I itself is much smaller than the main current I1, even if high frequency noise is superimposed on the main current I1, the magnitude of the high frequency component contained in the sense current I is very small. However, from the relationship of V1 = L × (dI / dt), the voltage V1 increases as the frequency of the high frequency component increases, so that the voltage V1 can be easily detected. Thereby, it is possible to detect that high-frequency noise is superimposed on the main current I1, that is, that partial discharge has occurred in the load.

  Note that the magnitude of the voltage V1 and the magnitude of the high-frequency component of the sense current I can be regarded as having a correlation. That is, the voltage V1 increases as the high frequency component of the sense current I increases. This indicates that the lower the voltage V1, the lower the insulation of the load.

  Thus, according to the first embodiment, the IPM monitors the partial discharge of the load. Therefore, according to the first embodiment, it is not necessary to provide a device for measuring partial discharge in or near the load. Further, as shown in FIG. 1, partial discharge can be monitored online by sending signals S <b> 1 and S <b> 2 to the control device 104. Furthermore, partial discharge generated in the load can be monitored in real time.

[Embodiment 2]
FIG. 3 is a diagram illustrating a configuration example of the semiconductor module according to the second embodiment.

  Referring to FIGS. 3 and 1, IPM 100 </ b> A is different from IPM 100 in that it includes U-phase arm 1 </ b> A instead of U-phase arm 1. V-phase arm 2 and W-phase arm 3 have the same configuration as U-phase arm 1A. Since the configuration of other parts of IPM 100A is the same as the configuration of the corresponding part of IPM 100, the following description will not be repeated.

  The U-phase arm 1A differs from the U-phase arm 1 in that it includes monitoring units 11A and 12A instead of the monitoring units 11 and 12. Since the structure of the other part of U-phase arm 1A is similar to the structure of the corresponding part of U-phase arm 1, the following description will not be repeated.

  The monitoring units 11A and 12A can not only monitor the partial discharge of the load, but also can detect the magnitude of the main current output from the IGBT element as in the conventional IPM.

  Monitoring units 11A and 12A monitor the presence or absence of high-frequency components contained in the sense currents output from IGBT elements Q1 and Q2, respectively, and output signals S1 and S2 indicating the monitoring results, respectively. This is the same as in the first embodiment.

  Monitoring unit 11A detects the magnitude of the current output from the main cell of IGBT element Q1, and outputs signal S1A indicating the detection result. Drive circuit 21 receives signal S1A, and turns off IGBT element Q1 when detecting that the current flowing through IGBT element Q1 is excessive, for example.

  Monitoring unit 12A detects the magnitude of the current output from the main cell of IGBT element Q2, and outputs signal S2A indicating the detection result. Drive circuit 22 receives signal S2A, and turns off IGBT element Q2 when detecting that the current flowing through IGBT element Q2 is excessive, for example.

FIG. 4 is a diagram showing the configuration of the IGBT element Q1 and the monitoring unit 11A in FIG.
With reference to FIG. 4, the monitoring unit 11 </ b> A includes a current sensor SNS and a monitoring unit 11. The current sensor SNS includes a resistor R1 and a voltage detection unit 41A provided corresponding to the resistor R1.

  One end of resistor R1 is coupled to pad P2, and the other end of resistor R1 is coupled to one end of inductor L1. When the sense current I flows through the resistor R1, a voltage V1A is generated. The voltage detector 41A detects this voltage V1A and outputs the detection result as a signal S1A.

  Also, the configuration of monitoring unit 11 shown in FIG. 4 is similar to the configuration of monitoring unit 11 shown in FIG.

  In the first embodiment, the monitoring unit 11 can detect only the high-frequency component of the sense current I. In other words, the low frequency component of the sense current I cannot be detected in the first embodiment. That is, in the first embodiment, the magnitude of the current flowing through the three-phase motor 102 during the operation of the three-phase motor 102 cannot be detected.

  On the other hand, in the second embodiment, the low frequency component and the high frequency component of the sense current I can be detected by using the resistor R1 and the inductor L1. Thus, according to the second embodiment, not only the magnitude of the current flowing through the load can be detected by the current flowing out from one sense cell unit, but also the occurrence of partial discharge in the load can be detected.

  In FIG. 4, the resistor R1 is provided closer to the IGBT element Q1 than the inductor L1, but the inductor L1 may be provided closer to the IGBT element Q1 than the resistor R1.

[Embodiment 3]
The overall configuration of the semiconductor module of the third embodiment is the same as the configuration of IPM 100A shown in FIG. However, the third embodiment is different from the second embodiment in the configuration of the IGBT element Q1 and the monitoring unit 11A shown in FIG. Therefore, hereinafter, the configuration of the IGBT element Q1 and the monitoring unit 11A will be described.

  FIG. 5 is a diagram showing a configuration of IGBT element Q1 and monitoring unit 11A in the third embodiment.

  Referring to FIGS. 5 and 4, in the third embodiment, IGBT element Q <b> 1 includes a sense cell unit 33 in addition to main cell unit 31 and sense cell unit 32. In this respect, the third embodiment is different from the second embodiment.

  The sense cell unit 33 has a pad P3 corresponding to the sense emitter terminal. When the main current I1 is output from the pad P1 of the main cell unit 31, a sense current I2 proportional to the main current I1 is output from the pad P3.

  The current sensor SNS detects the magnitude of the sense current I2. One end of resistor R1 is coupled to pad P3, and the other end of resistor R1 is coupled to terminal TU. When the sense current I2 flows through the resistor R1, a voltage V2 is generated across the resistor R1. The voltage detector 41A detects the voltage V2 and outputs a signal S1A indicating the detection result.

  The magnitude of the current output from the sense cell unit depends on the area of the sense cell unit. In order to accurately detect both the magnitude of the main current I1 and the magnitude of the high-frequency noise included in the main current I1, it is better to set the amount of current flowing through the resistor R1 and the amount of current flowing through the inductor L1 separately. There is also.

  The areas of the sense cell portions 32 and 33 are set to areas corresponding to the amounts of current flowing through the resistor R1 and the inductor L1, respectively. Thus, according to the third embodiment, the partial discharge of the load can be detected with high accuracy, and the magnitude of the current flowing through the load (the magnitude of the main current) can be detected with high accuracy.

[Embodiment 4]
The overall configuration of the semiconductor module of the fourth embodiment is the same as the configuration of IPM 100 shown in FIG. However, the internal configuration of the monitoring units 11 and 12 shown in FIG. Hereinafter, the configuration of the monitoring unit 11 will be described representatively. Since the configuration of monitoring unit 12 is the same as that of monitoring unit 11, the following description will not be repeated.

  FIG. 6 is a diagram showing the configuration of the IGBT element Q1 and the monitoring unit 11 in the fourth embodiment.

  Referring to FIG. 6, monitoring unit 11 includes an inductor L1, a filter F1, and a voltage detection unit 41. As can be seen from FIG. 6 and FIG. 2, in the fourth embodiment, a filter F1 is provided before the inductor L1. The input terminal of filter F1 is coupled to pad P2, and the output terminal of filter F1 is coupled to one end of inductor L1. In this respect, the semiconductor module of the fourth embodiment is different from the semiconductor module of the first embodiment.

  When the main current I1 is output from the pad P1, a sense current I0 proportional to the main current I1 is output from the pad P2. The filter F1 is provided to cut a frequency component having a frequency of 10 MHz or less, for example.

  In many cases, the frequency of the high-frequency signal superimposed on the main current when a partial discharge of the load occurs is about several GHz. Therefore, the sense current I0 also includes a high frequency component having a frequency of about several GHz. The filter F1 removes a frequency component having a frequency lower than the high frequency component from the sense current I0.

  Most of the main current I1 is a low frequency component. In other words, most of the sense current is a low frequency component. Therefore, according to the first to third embodiments, it may be difficult to detect whether a high-frequency component is included in the sense current. On the other hand, since the low frequency component is removed from the sense current in advance in the fourth embodiment, the high frequency component can be accurately detected. Therefore, the partial discharge of the load can be detected with high accuracy.

  The monitoring unit 11 may further include a current sensor SNS shown in FIG. As a result, the magnitude of the main current I1 can also be detected in the fourth embodiment. However, in this case, it is necessary to provide a resistor closer to the IGBT element Q1 than the filter F1.

[Embodiment 5]
Since the overall configuration of the semiconductor module of the fifth embodiment is similar to the configuration of IPM 100 shown in FIG. 1, the following description will not be repeated. The fifth embodiment differs from the fourth embodiment in the type of filter provided in the monitoring unit 11. Hereinafter, like the fourth embodiment, the configuration of the monitoring unit 11 will be described representatively. Since the configuration of monitoring unit 12 is the same as that of monitoring unit 11, the following description will not be repeated.

  FIG. 7 is a diagram showing the configuration of IGBT element Q1 and monitoring unit 11 in the fifth embodiment.

  7 and 6, in the fifth embodiment, monitoring unit 11 includes a filter F2 that is a bandpass filter instead of filter F1. In this respect, the fifth embodiment is different from the fourth embodiment. Since the configuration of other parts of monitoring unit 11 shown in FIG. 7 is the same as the configuration of the corresponding part of monitoring unit 11 shown in FIG. 6, the following description will not be repeated.

  The filter F2 selectively passes only the high frequency component contained in the sense current I0. The filter F2 outputs a high frequency component (indicated as the sense current I in FIG. 7) included in the sense current I0. Therefore, according to the fifth embodiment, the partial discharge of the load can be detected with high accuracy.

  The lower limit value and the upper limit value of the frequency band of the bandpass filter can be determined by the following method, for example. For example, the lower limit value is set according to the switching waveform of current during load operation (particularly at the time of rising). How steep the current waveform at the time of rising depends on the characteristics of a semiconductor switching element used for IPM such as IGBT. If the rising frequency is 500 kHz, the lower limit value is set slightly higher than 500 kHz (for example, 1 MHz). On the other hand, the upper limit of the frequency of the high-frequency component accompanying partial discharge is generally considered to be about several GHz. Considering this point, the upper limit value is set to 10 GHz, for example.

  In the fifth embodiment, the monitoring unit 11 may further include a current sensor SNS shown in FIG. Thus, the magnitude of the main current I1 can be detected also in the fifth embodiment. However, in this case, it is necessary to provide a resistor closer to the IGBT element Q1 than the filter F2 as in the fourth embodiment.

[Embodiment 6]
FIG. 8 is a diagram illustrating a configuration example of the semiconductor module according to the sixth embodiment.

  Referring to FIGS. 8 and 1, IPM 100 </ b> B is different from IPM 100 in that it includes U-phase arm 1 </ b> B instead of U-phase arm 1. V-phase arm 2 and W-phase arm 3 have the same configuration as U-phase arm 1B. Since the configuration of other parts of IPM 100B is similar to the configuration of the corresponding part of IPM 100, the following description will not be repeated.

  The U-phase arm 1B differs from the U-phase arm 1 in that it includes monitoring units 11B and 12B instead of the monitoring units 11 and 12. Since the structure of the other part of U-phase arm 1B is the same as the structure of the corresponding part of U-phase arm 1, the following description will not be repeated.

  When the monitoring units 11B and 12B detect that the partial discharge of the three-phase motor 102 has increased to some extent, signals S11 and S12 indicating to the control device 104 that the detection result, that is, the partial discharge of the load has increased to some extent. Respectively. When the control device 104 is a computer having a display screen, for example, when the control device 104 receives the signals S11 and S12, the control device 104 displays a message on the screen informing that the insulation deterioration is progressing.

FIG. 9 shows a configuration of IGBT element Q1 and monitoring unit 11B shown in FIG.
Referring to FIGS. 9 and 2, monitoring unit 11 </ b> B is different from monitoring unit 11 in that it includes a voltage detection unit 41 </ b> B instead of voltage detection unit 41. Since the configuration of other parts of monitoring unit 11B is the same as that of monitoring unit 11, the following description will not be repeated.

  FIG. 10 is a diagram schematically showing the waveform of the voltage V1 generated across the inductor L1 in FIG.

  Referring to FIGS. 10 and 9, when the operation of three-phase motor 102 is continued with partial discharge generated in three-phase motor 102, the peak value of voltage V <b> 1 increases as time t elapses.

  Generally, the magnitude of partial discharge increases as insulation deterioration progresses. When partial discharge increases, the probability of dielectric breakdown increases. The magnitude of the voltage V1 has a correlation with the magnitude of the partial discharge (that is, the magnitude of the high-frequency component contained in the sense current I). In other words, the fact that the peak of the voltage V1 gradually increases indicates that the insulation deterioration is progressing.

  The voltage detector 41B monitors whether or not the value of the voltage V1 is equal to or higher than the threshold value VH, and outputs a signal S11 as a monitoring result. As a result, the IPM 100B can notify the outside that there is a high possibility that the load will cause a dielectric breakdown, that is, that the load needs to be maintained or replaced. The voltage detection unit 41B corresponds to the “voltage monitoring unit” of the present invention.

  There are various notification methods performed by the IPM according to the sixth embodiment. For example, the following method may be used.

FIG. 11 is a diagram showing a modification of the semiconductor module of the sixth embodiment.
Referring to FIGS. 11 and 8, IPM 100B1 includes U-phase arm 1B1 instead of U-phase arm 1B. U-phase arm 1B1 includes LEDs (Light Emitting Diodes) 51A and 52A, a lighting circuit 51 that lights LED 51A when receiving signal S11, and a lighting circuit 52 that lights LED 52A when receiving signal S12. According to this configuration, for example, when a maintenance person looks at the IPM, it is possible to easily grasp whether maintenance (or replacement) of the three-phase motor is necessary.

  In the sixth embodiment, it is preferable that voltage detection unit 41B can change threshold value VH. For example, when a certain value is given from the control device 104, the voltage detection unit 41B changes the stored threshold value VH to the value given from the control device 104.

  The magnitude of the partial discharge greatly depends on the rotating machine that is the load. In order to continue to use the rotating machine without causing dielectric breakdown, it is necessary to determine the remaining life of the rotating machine in consideration of the use or economic efficiency of the rotating machine.

  Even if the same rotating machine is shown in the drawing, the magnitude and ease of occurrence of partial discharge differ from one rotating machine to another. However, the size and the likelihood of partial discharge can be classified into several patterns. According to these patterns, it is possible to grasp to some extent empirically how long dielectric breakdown will occur, or the probability that dielectric breakdown will occur in the future.

  However, the magnitude of partial discharge in a rotating machine varies from one machine to another. For this reason, even if the tendency of the partial discharge can be roughly grasped, the magnitude of the partial discharge of the rotating machine cannot be accurately determined unless it is actually operated. For this reason, it is preferable to adjust the threshold value VH after measuring the actual partial discharge magnitude.

  As described above, according to the sixth embodiment, when the partial discharge has progressed, the IPM notifies that the partial discharge has progressed. This makes it possible to perform load maintenance or replacement before dielectric breakdown occurs.

[Embodiment 7]
FIG. 12 is a diagram illustrating a configuration example of a semiconductor module according to the seventh embodiment.

  Referring to FIGS. 12 and 1, IPM 100 </ b> C is different from IPM 100 in that it includes U-phase arm 1 </ b> C instead of U-phase arm 1. V-phase arm 2 and W-phase arm 3 have the same configuration as U-phase arm 1C. Since the configuration of other parts of IPM 100C is similar to the configuration of the corresponding part of IPM 100, the following description will not be repeated.

  The U-phase arm 1C is different from the U-phase arm 1 in that it includes monitoring units 11C and 12C instead of the monitoring units 11 and 12. Since the structure of the other part of U-phase arm 1C is the same as the structure of the corresponding part of U-phase arm 1, the following description will not be repeated.

  Specifically, the monitoring units 11C and 12C are inductors. As shown in FIG. 12, the inductors L1 and L2 correspond to the monitoring units 11C and 12C, respectively.

  One end of inductor L1 is coupled to the sense emitter terminal of IGBT element Q1 and terminal T1A, and the other end of inductor L1 is coupled to terminal T1B and terminal TU. One end of inductor L2 is coupled to sense emitter terminal of IGBT element Q2 and terminal T2A, and the other end of inductor L2 is coupled to terminal T2.

  Inductor L1 time-differentiates a high-frequency component included in the sense current output from the sense emitter terminal of IGBT element Q1. As a result, a voltage V1 is generated across the inductor L1. Since the terminals T1A and T1B are coupled to both ends of the inductor L1, the voltage between the terminals T1A and T1B becomes equal to the voltage V1.

  Inductor L2 time-differentiates a high-frequency component included in the sense current output from the sense emitter terminal of IGBT element Q2. As a result, a voltage V3 (electromotive voltage) is generated across the inductor L2. Since the terminals T2A and T2 are coupled to both ends of the inductor L2, the voltage between the terminals T2A and T2 becomes equal to the voltage V3.

  The control device 104 receives the voltages V1 and V3 and monitors the presence or absence of partial discharge in the three-phase motor 102. That is, the control device 104 functions as a monitoring device.

  For example, when a plurality of IPMs 100C are provided corresponding to a plurality of rotating machines, control device 104 receives voltages corresponding to voltages V1 and V3 from each IPM 100C. As a result, the control device 104 can collectively monitor the progress of insulation deterioration of a plurality of rotating machines.

  Further, according to the semiconductor module of the seventh embodiment, the configuration of the monitoring unit can be simplified.

  In addition, the detection function with which the semiconductor module of this invention is provided is not limited to the use for detecting the partial discharge of load. The semiconductor module of the present invention can detect the frequency component even if the sense current contains a frequency component whose frequency is higher than the switching frequency of the semiconductor switching element.

  In the above description, a rotating machine is shown as an example of the load. However, partial discharge due to insulation deterioration is commonly seen in electrical equipment. That is, the semiconductor module of this embodiment can also monitor partial discharges generated in electrical devices other than the rotating machine, connection cables, and the like.

  Further, in the above description, the IGBT is shown as the semiconductor switching element used in the semiconductor module of the present embodiment. However, as a semiconductor switching element, for example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) having a current sense function may be used in the semiconductor module of the present embodiment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

FIG. 3 is a diagram illustrating a configuration example of a semiconductor module according to the first embodiment. It is a figure which shows the structure of IGBT element Q1 and the monitoring part 11 of FIG. FIG. 6 is a diagram illustrating a configuration example of a semiconductor module according to a second embodiment. It is a figure which shows the structure of IGBT element Q1 and monitoring part 11A of FIG. It is a figure which shows the structure of IGBT element Q1 in Embodiment 3, and the monitoring part 11A. It is a figure which shows the structure of IGBT element Q1 in Embodiment 4, and the monitoring part 11. FIG. It is a figure which shows the structure of IGBT element Q1 in Embodiment 5, and the monitoring part 11. FIG. FIG. 10 is a diagram illustrating a configuration example of a semiconductor module according to a sixth embodiment. It is a figure which shows the structure of IGBT element Q1 and monitoring part 11B shown in FIG. It is a figure which shows typically the waveform of the voltage V1 which generate | occur | produces at the both ends of the inductor L1 of FIG. FIG. 10 is a diagram showing a modification of the semiconductor module of the sixth embodiment. FIG. 11 is a diagram illustrating a configuration example of a semiconductor module according to a seventh embodiment.

Explanation of symbols

  1, 1A, 1B, 1B1, 1C U-phase arm, 2 V-phase arm, 3 W-phase arm, 11, 12, 11A, 12A, 11B, 12B, 11C, 12C monitoring unit, 21, 22 drive circuit, 31 main cell Part, 32, 33 sense cell part, 41, 41A, 41B voltage detection part, 51, 52 lighting circuit, 51A, 52A LED, 100, 100A, 100B, 100B1, 100C IPM, 102 three-phase motor, 104 control device, D1, D2 diode, F1, F2 filter, L1, L2 inductor, P1-P3 pad, Q1, Q2 IGBT element, R1 resistance, SNS current sensor, T1, T2, TU, TV, TW, T1A, T1B, T2A terminals.

Claims (2)

A semiconductor switching element having a main cell portion for outputting a main current and a sense cell portion for outputting a sense current proportional to the main current;
A detector that detects whether or not a predetermined frequency component having a frequency higher than the switching frequency of the semiconductor switching element is included in the sense current;
The detector, whereas the sense current flows toward the other end from the end, an inductor Ru is generated between the other end and the one end an electromotive voltage corresponding to the predetermined frequency component as a detection signal,
It said inductor being connected in series, viewed contains a current sensor for detecting the magnitude of the sense current,
The main current flows to a load connected to the semiconductor module,
The predetermined frequency component is a frequency component corresponding to a frequency component of high-frequency noise superimposed on the main current with a partial discharge of the load ,
The semiconductor module , wherein the current sensor is a resistance element .   The semiconductor module according to claim 1, further comprising first and second output terminals respectively coupled to the one end and the other end of the inductor.

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