GB2529018A

GB2529018A - Power converter

Info

Publication number: GB2529018A
Application number: GB1508151.6A
Authority: GB
Inventors: Masaomi Konishide; Kohhei ONDA; Katsumi Ishikawa; Takeshi Tanaka
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2014-06-11
Filing date: 2015-05-13
Publication date: 2016-02-10
Anticipated expiration: 2035-05-13
Also published as: JP6483963B2; JP2015233395A; GB201508151D0; DE102015210563A1; GB2529018B; DE102015210563B4

Abstract

A power converter capable of enhancing electric current detection accuracy by minimizing inductance of gate wiring. A power converter, particularly suitable for railway vehicles, includes a power semiconductor module 1, 2 equipped with a main emitter terminal 12, 22, a gate terminal 13, 23 and an auxiliary emitter terminal, 14, 24, and a gate drive substrate 15, 25 connected to the power semiconductor module, wherein the power semiconductor module and the gate drive substrate are connected by a metal conductor plate 16, 26. The metal conductor plate may connect the main emitter terminal and the gate drive substrate. The metal conductor plate may be installed between the main emitter terminal and another conductor plate installed above the main emitter terminal. The power semiconductor module may be an IGBT (Insulated Gate Bipolar Transistor).

Description

[0001] The present invention relates to a power converter and is particularly suited for use in a power converter used for railway vehicles.

[Background Art]

[0002] A power converter generally used for railway vehicles is configured by including an inverter for converting direct current power into alternating current power, a converter for converting the alternating current power into the direct current power, and a circuit such as a DC chopper that increases or decreases a direct current voltage. Furthermore, regarding such circuits, a power semiconductor called an IGBT (Insulated Gate Bipolar Transistor) is widely used.

[0003] The power semiconductor is driven by on and off signals from a gate drive substrate and the gate drive substrate is driven by a signal from a control theory unit that is a controller for a transducer. The power semiconductor and the gate drive substrate are connected by wiring called gate wiring and the gate drive substrate can detect an electric current running through the power semiconductor by connecting the power semiconductor and the gate drive substrate via this gate wiring.

[0004] The gate drive substrate is equipped with a protection function that protects the power semiconductor; and one of the protection function is a shod-circuit protection function. In order to judge a short circuit, there is a method for judging the short circuit based on a voltage occurring between emitter inductances between a main emitter terminal and an auxiliary emitter terminal that are installed within a module including the power semiconductor (which is called a power semiconductor module).

[0005] PTL 1 discloses a power converter equipped with the short-circuit protection function that judges a short circuit based on a voltage generated between emitter inductances. Specifically speaking, PTL 1 discloses a technique that installs the inductances in series with a main terminal of a switching element (power semiconductor) and has an integrating circuit integrate voltages occurring at both ends of the inductances at the time of switching, thereby judging a short circuit by detecting an electric current running through the power semiconductor.

[Citation List] [Patent Literature] [0006] [P11 1] Japanese Patent Application Laid-Open (Kokai) Publication No. 2000-

[Summary of Invention]

[Problems to be Solved by the Invention] [0007] However, regarding the power converter described in PTL 1, no specific structure of the gate wiring that connects the power semiconductor module and the gate drive substrate is disclosed.

[0008] Fig. 7 illustrates the structure of general gate wiring. The gate wiring is composed of main emitter wiring for connecting main emitter terminals and a gate drive substrate, and auxiliary emitter wiring for connecting auxiliary emitter terminals and the gate drive substrate.

[0009] Furthermore, the gate wiring is formed generally by making a stranded wire using two wires of the main emitter wiring and the auxiliary emitter wiring in order to minimize the inductance. However, in this case, the inductance may not be further reduced to a value lower than a certain value and an electric current running through the power semiconductor may be mistakenly detected due to common mode noises superposed on the wiring.

[0010] The present invention was devised in consideration of the above-described circumstances and suggests a power converter capable of enhancing electric current detection accuracy by minimizing the inductance of the gate wiring.

[Means for Solving the Problems] [0011] In view of the above-described problems, proposed is a power converter according to the present invention, that is, a power converter for railway vehicles including a power semiconductor module equipped with a main emitter terminal, a gate terminal, and an auxiliary emitter terminal, and a gate drive substrate connected to the power semiconductor module, wherein the power semiconductor module and the gate drive substrate are connected by a metal conductor plate.

[Advantageous Effects of Invention] [0012] According to the present invention, the electric current detection accuracy can be enhanced by minimizing inductance of the gate wiring.

[Brief Description of Drawings]

[0013] [Fig. 1] Fig. 1 is a perspective view of a power converter; [Fig. 2] Fig. 2 is a side view of the power converter; [Fig. 3] Fig. 3 is a front view of the power converter; [Fig. 4] Fig. 4 is a circuit configuration diagram of the power converter; [Fig. 5] Fig. 5 is a perspective view of another power converter; [Fig. 6] Fig. 6 is a perspective view of a power converter equipped with a U-shaped metal conductor plate; and [Fig. 7] Fig. 7 is a configuration diagram illustrating general gate wiring.

[Mode for Carrying out the Invention]

[0014] An embodiment of the present invention will be described in detail with reference to drawings.

[0015] (1) Overall Structure Fig. 1 illustrates a perspective structure of a power converter according to a first embodiment. Particularly, Fig. 1 illustrates one phase of a two-level inverter equipped with two 1-in-i type semiconductor modules, regarding each of which one power semiconductor is mounted in one power semiconductor module.

[0016] The power converter includes an upper-arm semiconductor module (IGBT module) 1 and a lower-arm IGBT module 2. Since the upper-arm IGBT module 1 has the same structure as that of the lower-arm IGBT module 2, particularly the structure of the lower-arm IGBT module 2 will be explained below.

[0017] The IGBT module 2 is configured by including a plurality of main collector terminals 21, a plurality of main emitter terminals 22, a gate terminal 23, and an auxiliary emitter terminal 24. The IGBT module 2 has two protrusions and the main collector terminals 21 are installed on a top surface of one of the two protrusions. Also, the main emitter terminals 22 are installed on a top surface of the other protrusion.

[0018] Furthermore, regarding the top surface of the IGBT module 2, the gate terminal 23 and the auxiliary emitter terminal 24 are installed on a flat part which is an area excluding the protrusions. Of these terminals 21 to 24, the main emitter terminals 22, the gate terminal 23, and the auxiliary emitter terminal 24 are connected to a gate drive substrate 25 that drives the IGBT module 2.

[0019] The gate drive substrate 25 is directly connected to the gate terminal 23 and the auxiliary emitter terminal 24 and is connected to the plurality of main emitter terminals 22 via a metal conductor plate (emitter sense patchboard) 26. In other words, the emitter sense patchboard 26 connects the plurality of main emitter terminals 22 and the gate drive substrate 25.

[0020] The emitter sense patchboard 26 is installed so that it covers the top surface of the protrusion, on which the main emitter terminals 22 are installed, on the top surface of the IGBT module 2, extends as if falling down perpendicularly along a side face of this protrusion to the flat part, and is then connected to the gate drive substrate 25.

[0021] Furthermore, as widths Wi and W2 of the emitter sense patchboard 26 are wider, inductance between the main emitter terminals 22 and the gate drive substrate can be reduced. Therefore, in this example, the emitter sense patchboard 26 at its connecting part connected to the main emitter terminals 22 has width Wi equal to or more than an installment width of the plurality of main emitter terminals 22 and the emitter sense patchboard 26 at its part falling down perpendicularly along the side face of the protrusion to the flat part has width W2 equal to or more than the connection width connected to the gate drive substrate 25.

[0022] Incidentally, the power converter includes, in addition to each element (21 to 26) described above, for example, a positive conductor plate 31 for connecting a positive-side power source (not shown in the drawing) and main collector terminals 11, an intermediate conductor plate 32 for connecting main emitter terminals 12 of the upper arm and main collector terminals 21 of the lower arm, and a negative conductor plate 33 for connecting a negative-side power source (not shown in the drawing) and main emitter terminals 22. The power converter also includes, for example, an alternating current output terminal 41 and a cooling device 51 for cooling the IGBT module 2.

[0023] Each element (21 to 26) described above is an element relating to the lower-arm IGBT module 2 and the upper-arm IGBT module 1 is configured similarly. For example, the structure in which the emitter sense patchboard 26 of the lower arm connects the main emitter terminals 22 and the gate drive substrate 25 applies similarly to the upper arm. In the upper arm, an emitter sense patchboard 16 connects the main emitter terminals 12 and a gate drive substrate 15.

[0024] (2) Side Face Structure Fig. 2 illustrates a side face structure of the power converter in Fig. 1. The power converter includes two upper-arm and lower-arm IGBT modules 1 and 2 on the cooling device 51 as explained above. Then, each of the main emitter terminals 12 and 22 installed on one of the two protrusions included in each of these IGBT module 1 and 2 is connected to the emitter sense patchboard 16 and 26. Also, each of these emitter sense patchboard 16 and 26 is connected to the gate drive substrate 15, 25.

[0025] Of ends of the negative conductor plate 33, a height adjuster 331 is provided on an under surface of an end of the negative conductor plate 33 set above the protrusions of the IGBT module 2. This height adjuster 331 is composed of the same material as that of the negative conductor plate 33 and keeps the negative conductor plate 33 horizontal.

[0026] (3) Front Face Structure Fig. 3 illustrates a front structure of the power converter in Fig. 1. This drawing particularly illustrates a front structure of the lower-arm IGBT module 2. As seen from the front side of this IGBT module 2, there are air gaps between the main emitter terminals 22 and an outside package surface of the IGBT module 2. Incidentally, the air gaps are omitted in Fig. 1 and Fig. 2 to simply the illustrations. Since the emitter sense patchboard 26 is of a flat plate shape, the emitter sense patchboard 26 can be inserted and set into these air gaps.

[0027] (4) Circuit Structure Fig. 4 illustrates a circuit structure of the power converter. It should be noted that a circuit structure of the IGBT module 2 and its peripheral area will be explained in this section and the same circuit structure applies to that of the IGBT module 1 and its peripheral area. The power converter is configured by including a control theory unit 61 in addition to the gate drive substrate 25 and the IGBT module 2 which have been described above.

[0028] The control theory unit 61 outputs an on-off signal Si to the gate drive substrate 25. After inputting the on-off signal Si from the control theory unit 61, a gate drive circuit 251 within the gate drive substrate 25 converts the on-off signal 51 into an on-off signal S2 for the IGBT module 2 and outputs this on-off signal S2 to the IGBT module 2.

[0029] When the on-off signal S2 from the gate drive circuit 251 is input to the gate terminal 23 within the IGBT module 2, the IGBT module 2 applies a collector current to between the main collector terminals 21 and the main emitter terminals 22 when it is on.

When the IGBT module 2 is off, it applies a power supply voltage, which is not shown in the drawing, to between the main collector terminals 21 and the main emitter terminals.

[0030] The auxiliary emitter terminal 24 within the IGBT module 2 is a terminal which applies en electric current running when the on-off signal S2 is input to the gate terminals 23, and which is equipotential to the main emitter terminal 22; however, in the IGBT module 2, the auxiliary emitter terminal 24 is configured as a separate terminal from the main emitter terminal 22.

[0031] Since the main emitter terminal 22 and the auxiliary emitter terminal 24 are connected by the emitter sense patchboard 26 within the IGBT module 2, a parasitic wiring inductance Le is formed. Furthermore, the main emitter terminal 22 and the auxiliary emitter terminal 24 are connected to an electric current detection circuit 252 within the gate drive substrate 25.

[0032] The electric current detection circuit 252 integrates a voltage generated by the wiring inductance Le, detects an electric current which runs between the main collector terminal 21 and the main emitter terminal 22, and outputs electric current information S3 obtained as detection results to a short-circuit judgment circuit 253.

[0033] The short-circuit judgment circuit 253 judges whether the state is normal or abnormal (short circuit), based on the electric current information S3; and if a heavy current which would destroy the IGBT module 2 is running, the short-circuit judgment circuit 253 determines that the state is abnormal. In this case, the short-circuit judgment circuit 253 outputs an off signal S4, which forces the electric current running through the IGBT module 2 to be turned off, to the gate drive circuit 251. As a result, the IGBT short-circuit protection is implemented.

[0034] In this example, the emitter sense patchboard 26 is of a wide-width flat plate shape and establishes the shortest route to connect the IGBT module 2 and the gate drive substrate 25. Since the emitter sense patchboard 26 is formed of the wide-width shortest route, it is possible to prevent superposing of noises by minimizing the parasitic inductance.

[0035] Therefore, it is possible to prevent problems such as stopping operation of the inverter by judging the status to be a short circuit by false detection of a detected value of the electric current or continuing the operation of the inverter withoutjudging the status to be the short circuit when the short circuit has actually occurred.

[0036] (5) Advantageous Effects of First Embodiment The power converter according to the first embodiment is configured as described above so that the plurality of main emitter terminals 12, 22 and the gate drive substrate 15,25 which are installed in the IGBT module 1,2 are connected by the emitter sense patchboard 16, 26, respectively, to minimize inductance between them. So, it is possible to enhance the electric current detection accuracy by preventing false detection.

[0037] Furthermore, each of the emitter sense patchboards 16 and 26 has a wide width within the range capable of mutually maintaining the insulating relationship and is designed to establish the shortest route to connect the main emitter terminals 12 and 22 and the gate drive substrates 15 and 25, respectively, so that it is possible to minimize the inductance. Therefore, it is possible to enhance the electric current detection accuracy by preventing false detection.

[0038] Incidentally, the first embodiment has described the gate drive substrate 25 as one substrate; however, the invention is not limited to this example and, for example, the gate drive substrate 25 may be composed of separate substrates, that is, a substrate equipped with the shod-circuit protection function and a substrate to receive the signal from the control theory unit 61. In this case, only the substrate equipped with the short-circuit protection function may be located very close to the IGBT modules 1 and 2 and the wide-width emitter sense patchboards 16 and 26 may be used to establish the shortest route to connect this substrate and the main emitter terminals 12 and 22, respectively. Consequently, the aforementioned advantageous effect of enhancing the electric current detection accuracy can be obtained.

[0039] Furthermore, the first embodiment has described the structure in which the two IGBT modules 1 and 2 are not connected in parallel; however, the invention is not limited to this example and, for example, a plurality of IGBT modules may be connected in parallel and one gate drive substrate may be connected to these IGBT modules in an integrated manner. In this case as well, the aforementioned advantageous effect of enhancing the electric current detection accuracy can be obtained by using the plate-shaped emitter sense patchboard.

[0040] Furthermore, the first embodiment has described the two-level inverter as an example; however, the invention can be applied to a multi-level inverter of three or higher levels.

[0041] (6) Second Embodiment Fig. 5 illustrates a perspective structure of a power converter according to a second embodiment. The difference between the power converter according to the second embodiment and the power converter according to the first embodiment is that the power converter according to the second embodiment includes: a 2-in-i type power semiconductor module, that is, one power semiconductor module equipped with two upper-arm and lower-arm power semiconductors; and a 2-in-i type gate drive substrate, that is, one substrate for driving the two upper-arm and lower-arm power semiconductors.

The different structure will be explained below.

[0042] An IGBT module 2A is configured by including: a main collector terminal iiA, a main emitter terminal i 2A, a gate terminal i 3A, and an auxiliary emitter terminal i 4A for the upper arm; and a main collector terminal 2iA, a main emitter terminal 22A, a gate terminal 23A, and an auxiliary emitter terminal 24Afor the lower arm.

[0043] Of these terminals i iA to i 4A and 2iA to 24A, the main emitter terminals i 2A, 22A, the gate terminals iSA, 23A, and the auxiliary emitter terminals i4A and 24A are respectively connected to a gate drive substrate 25A that drives the IGBT module 2A.

[0044] The gate drive substrate 25A is composed of one substrate that integrates substrates for driving the upper arm and for driving the lower arm and is directly connected to the gate terminals i3A, 23A and the auxiliary emitter terminals 14A and 24A. The gate drive substrate 25A is also connected to the main emitter terminals i2A and 22A via emitter sense patchboards i6A and 26A. In other words, the emitter sense patchboards i 6A and 26A connect the main emitter terminals i 2A and 22A and the gate drive substrate 25A.

[0045] The emitter sense patchboard i6A is installed so that it covers a top surface of a protrusion, on which the main emitter terminal 12A of the upper arm is installed, extends as if falling down perpendicularly along a side face of this protrusion to a flat part, and is then connected to the gate drive substrate 25A.

[0046] Furthermore, the emitter sense patchboard 26A is installed so that it covers a top surface of a protrusion on which the main emitter terminal 22A of the lower arm, extends to another protrusion different from the above-mentioned protrusion, further extends as if falling down perpendicularly along a side face of the other protrusion to the flat part, and is then connected to the gate drive substrate 25A.

[0047] As widths W3 and W4 of the emitter sense patchboards 1 GA and 26A are wider, inductance between the main emitter terminals 12A and 22A and the gate drive substrate 25A can be reduced. Therefore, the emitter sense patchboards 16A and 26A have maximum widths W3 and W4 within the range capable of mutually maintaining the insulating relationship.

[0048] (7) Advantageous Effects of Second Embodiment When the power converter according to the second embodiment described above is employed, the inductance between the main emitter terminals 12A and 22A and the gate drive substrate 25A can be minimized by using the emitter sense patchboards 1 6A and 26A to connect them even if the power converter includes the 2-in-i type IGBT module 2A and gate drive substrate 25A. Therefore, it is possible to enhance the electric current detection accuracy by preventing false detection.

[0049] Incidentally, the power converter includes the 2-in-i type IGBT module 2A in this embodiment; however, the invention is not limited to this example and, for example, the power converter may include a 6-in-i type IGBT module composed of six arms in one package. Even in this case, the inductance between each main emitter terminal and the gate drive substrate can be minimized by connecting them via the emitter sense patchboard. Therefore, it is possible to enhance the electric current detection accuracy by preventing false detection.

[0050] (8) Another Embodiment Fig. 6 illustrates a perspective structure of a power converter according to another embodiment. This other power converter is different from the first embodiment because an emitter sense patchboard 26B is of a U-shape. Since the emitter sense patchboard 263 is of the U-shape, the emitter sense patchboard 263 can be installed easily into the air gaps between the main emitter terminals 22 and the outside package io surface of the power semiconductor module 2 even after the main emitter terminals 22 are installed on the power semiconductor module 2.

[Reference Signs List] [0051] 1, 2 power semiconductor module (IGBT module) 11, 21 main collector terminal 12,22 main emitter terminal 13, 23 gate terminal 14, 24 auxiliary emitter terminal 15, 25 gate drive substrate 16, 26 metal conductor plate (emitter sense patchboard)