JP2018019587A - Cell unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell unit in which an inductor for cell bypass is arranged between IGBT units arranged downstream and upstream in the ventilation direction, and inductance can be reduced without deteriorating cooling performance. An air-cooled cell unit having a plurality of IGBT modules and a cell bypass unit, wherein a first-phase IGBT module is arranged downstream in the ventilation direction, and a second-phase IBT module is arranged upstream in the ventilation direction. The cell bypass unit is disposed between the first phase and second phase IGBT modules, the output of the first phase IGBT module, the input of the cell bypass unit, and the second phase IGBT module. The output of the cell bypass unit and the output of the cell bypass unit are arranged to face each other to shorten the wiring length, reduce the inductance, and reduce the size. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a cell unit including a cell bypass unit portion in a main circuit constituting a large-capacity inverter.

  A large-capacity inverter may be configured by connecting a plurality of single-phase inverters called cell units in series. A plurality of IGBTs are used as switching elements in a cell unit used in such a large capacity inverter.

  In the event of a failure due to a DC short circuit or the like of an IGBT that constitutes a certain cell unit, the output of the failed cell unit that constitutes the large-capacity inverter is short-circuited by some short-circuit means, and the failed cell unit is bypassed, thereby May be required to operate continuously. Such a short-circuit means unit is called a cell bypass unit. The cell bypass unit may be composed of an IGBT.

  FIG. 5 is an example of a conventional cell unit 300 (hereinafter referred to as cell unit 300) that constitutes a large capacity inverter. The illustrated cell unit 300 includes a rectifying diode unit 110, a smoothing capacitor unit 120, an IGBT unit unit 130, a heat sink 140B, a cell bypass unit unit 200, and the like.

  The IGBT unit section 130 is composed of four IGBT modules including a first IGBT module IGBTTU1, a second IGBT module IGBTTU2, a third IGBT module IGBTTU3, and a fourth IGBT module IGBT4. Each IGBT module is a so-called 2IN1 module in which two IGBTs are connected in series, the connection point is used as an output of the IGBT module, and a diode is connected in antiparallel with each IGBT. Hereinafter, description of the diode is omitted.

  The first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 are connected in parallel to form the first phase of the single-phase output of the cell unit 300, and are arranged on the downstream side in the ventilation direction (the direction of “wind direction” in the figure). The third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 are connected in parallel to form the second phase of the single-phase output of the cell unit 300, and are arranged upstream in the ventilation direction.

  The cell bypass unit section 200 includes two cell bypass IGBT modules including a first bypass IGBT module IGBT1 and a second bypass IGBT module IGBT2. The first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 are so-called 1IN1 modules, each having a diode connected in reverse parallel to the IGBT in each package. .

  The emitters of the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 are connected to each other. The collector of the first bypass IBGT module IGBT1 is connected to the first-phase output of the cell unit 300, ie, the output of the first IGBT module IGBTTU1 and the output of the second IGBT module IGBTTU2. The collector of the second bypass IBGT module IGBT2 is connected to the second-phase output of the single-phase output of the cell unit 300, that is, the output of the third IGBT module IGBTTU3 and the output of the fourth IGBT module IGBTTU4. The first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 are arranged further downstream of the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 arranged on the downstream side in the ventilation direction.

  The rectifier diode part 110, the IGBT unit part 130, and the cell bypass unit part 200 are fixedly fixed to the heat sink 140B.

In addition, when the power converter is comprised by the several variable frequency conversion unit (inverter) and the said inverter fails, the method of optimizing an operating condition with a remaining unit (for example, refer patent document 1). ) Or a method in which when one power converter is controlled by two control devices, when one control device detects an abnormality, the other control device switches to continue the continuous operation (for example, Patent Literature 2) is known.

JP-A-9-275699 JP2011-41404A

  In such a heat sink 140B, the rectifier diode unit 110, the IGBT unit unit 130, and the cell bypass unit unit 200 are heat generation sources. There is a problem that the thermal resistance to the semiconductor constituting the IGBT unit portion 130 and the like increases. Therefore, in the conventional cell unit 300, the IGBT unit part 130 is divided into two parts, and the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 are interposed between the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4. In order to avoid concentration of the heat source, a predetermined gap was provided. When the cell bypass unit 100 is provided, the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 that do not generate heat are always arranged at the most downstream in the ventilation direction. The element cooling by adding two IGBT modules for bypass IGBT and the wiring route (inductance increase) to the cell bypass IGBT were problems. Further, there is a problem that the shape of the heat sink 140B is larger than that of the cell unit without the cell bypass unit 200.

  The present invention has been made to solve the above-described problems. By shortening the wiring between the IGBT unit section 130 and the cell bypass unit section 200, the inductance can be reduced, and further the cell bypass unit. An object of the present invention is to provide a cell unit to which heat sink of the same size as a cell unit without a cell bypass unit can be applied.

To achieve the above object, a cell unit according to claim 1 of the present invention is a single-phase output cell unit constituting a large-capacity inverter, and an IGBT unit constituting a first phase;
An IGBT module that comprises an IGBT unit that constitutes the second phase, and a cell bypass unit that short-circuits the output of the cell unit, and that constitutes the IGBT unit that constitutes the first phase on one air-cooled heat sink; The IGBT module that constitutes the IGBT unit that constitutes the second phase and the IGBT module that constitutes the cell bypass unit are tightly fixed, and the cell bypass unit includes the IGBT unit that constitutes the first phase and the second An IGBT that is arranged between the IGBT unit that constitutes the phase and is arranged so that the output terminal of the IGBT unit that constitutes the first phase and the first terminal of the cell bypass unit face each other, and that constitutes the second phase Arrange so that the output terminal of the unit and the second terminal of the cell bypass unit face each other. And connecting the output terminal of the IGBT unit constituting the first phase and the first terminal of the cell bypass unit with a bus bar, and connecting the output terminal of the IGBT unit constituting the second phase and the first of the cell bypass unit. The two terminals are connected by a bus bar.

  According to this invention, the wiring between the IGBT unit constituting the first phase and the IGBT unit constituting the second phase and the cell bypass IGBT can be shortened, and the inductance can be reduced. Even if a cell bypass unit exists, a cell unit to which a small heat sink comparable to a cell unit without a cell bypass unit can be applied can be provided.

An example of the layout of the cell unit 100 which comprises the large capacity inverter which concerns on Example 1. FIG. The circuit diagram of the cell unit 100 concerning FIG. The perspective view and front view of the cell unit 100 before this invention implementation which concern on Example 1. FIG. The perspective view and front view at the time of using the cell bypass unit part 200 for the cell unit 100 which concerns on Example 1. FIG. An example of a conventional cell unit 300B constituting a large capacity inverter.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is an example of a layout diagram of a single-phase output cell unit 100 constituting the large-capacity inverter according to the first embodiment. In addition, the same part as each part of FIG. 5 shows the same code | symbol, and abbreviate | omits description.

The illustrated cell unit 100 is a box-shaped solid body having a bottom as a bottom surface, and a wind direction indicated by an illustrated arrow is formed from a front surface to a rear surface by a ventilation unit (not illustrated).

  The cell unit 100 includes a heat sink 140, a rectifier diode unit 110, an IGBT unit unit 130, a cell bypass unit unit 200, a smoothing capacitor unit 120, and the like.

  A semiconductor module constituting the rectifier diode part 110, the IGBT unit part 130, and the cell bypass unit part 200 is closely bonded to the heat sink 140. The heat sink 140 absorbs the heat generated by the element and dissipates it into the air in the cell unit 100. The radiated heat is cooled by the wind flowing in the direction of the arrow shown above. That is, the heat sink 140 is an air-cooled heat sink. The heat sink 140 has a flat semiconductor mounting surface, to which the semiconductor modules constituting the rectifier diode part 110, the IGBT unit part 130, and the cell bypass unit part 200 are closely attached and joined to the heat sink 140. Cooling fins are formed on the surface of the heat sink 140 that faces the semiconductor mounting surface, and wind flows through this portion to efficiently cool the heat sink.

  The illustrated rectifier diode unit 110 includes, for example, rectifier diodes DR, DS, and DT for generating a DC voltage from the three-phase AC voltage supplied from the R phase, S phase, and T phase shown in FIG. . The generated DC voltage is supplied to the cell unit 100 according to the present embodiment.

  The IGBT unit section 130 includes a first IGBT module IGBTTU1 and a second IGBT module IGBTTU2 that constitute the first phase of the single-phase output of the cell unit 100 arranged on the downstream side in the ventilation direction (the direction of “wind direction” in the drawing). The third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 constituting the second phase of the single-phase output of the cell unit 100 arranged upstream in the ventilation direction are arranged with a predetermined interval. . This arrangement is a distance so that the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 and the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 are not affected by heat from each other. This is the same as the arrangement position of the first to fourth IGBT modules IGBTTU1 to IGBTTU4 in 300.

  In addition, the structure of the IGBT unit part 130 may differ in the structure of the IGBT unit part 130 by the capacity | capacitance of an inverter, and a use.

  The cell bypass unit unit 200 includes a first bypass IGBT module IGBT1 and a second bypass IGBT module IGBT2, and includes a first IGBT module IGBTTU1 and a first IGBT module that constitute a first phase of the single-phase output of the cell unit 100. The second IGBT module IGBTTU2 and the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 constituting the second phase of the single-phase output of the cell unit 100 are arranged.

  The smoothing capacitor unit 120 is provided below the heat sink 140 disposed in the cell unit 100, and includes ten smoothing capacitors.

  FIG. 2 is a circuit diagram of the cell unit 100 according to FIG. Hereinafter, the circuit configuration of the cell unit 100 will be briefly described with reference to FIG.

  In the illustrated example, a three-phase AC voltage is supplied to a terminal R (R phase), a terminal S (S phase), and a terminal T (T phase). As the supplied three-phase voltage, DC voltages rectified by the rectifier diodes DR, DS, and DT of the diode unit 110 are supplied to the P-phase and the N-phase, respectively.

  The DC voltages supplied to the P phase and the N phase in this way are smoothed by the capacitors CF <b> 1 to CF <b> 10 arranged in the smoothing capacitor unit 120 and supplied to the IGBT unit unit 130.

  In the first IGBT module IGBTTU1, two IGBTs are internally connected in series, and the connection point is used as an output to be the output terminal P1 of the IGBTTU1. A diode is connected in the reverse direction between the collector C and the emitter E of the IGBTTU1. That is, the IGBT module IGBTTU1 is a so-called 2IN1 module including an antiparallel diode. Hereinafter, the description of the diode will be omitted. The same applies to the other second to third IGBT modules IGBTTU2 to IGBT4.

  The first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 are connected in parallel to form the first phase of the single-phase output of the cell unit 100, that is, the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2. Is an IGBT unit constituting the first phase.

  The third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 are connected in parallel to form the second phase of the single-phase output of the cell unit 100, that is, the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4. Is an IGBT unit constituting the second phase.

  The output terminal P1 of the first IGBT module IGBTTU1 and the output terminal P2 of the second IGBT module IGBTTU2 are connected in parallel and further connected to the output terminal A of the cell unit 100. The output terminal P3 of the third IGBT module IGBTTU3 and the output terminal P4 of the fourth IGBT module IGBTTU4 are connected in parallel and connected to the output terminal B of the cell unit 100.

  Each of the gate terminals G of the first to fourth IGBT modules IGBTTU1 to IGBTTU4 configured as described above is connected to a control unit (not shown) and is controlled to be turned on / off by the control unit, thereby generating an AC voltage, and an output terminal. Output to A and B.

  There is a so-called 1IN1 module in which a diode is built in between the collector C and the emitter E of the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 constituting the cell bypass unit section 200 and connected in the opposite direction. used. The description of the diode is omitted hereinafter.

  Electrically, the output terminal A is connected to the input terminal (collector C) P5 of the first bypass IGBT module IGBT1 constituting the cell bypass unit part 200, and the output terminal B constitutes the cell bypass unit part 200. It is connected to an input terminal (collector C) P6 of the second bypass IGBT module IGBT2. The emitter E of the IGBT 1 is connected to the emitter E of the IGBT 2, and the bypass IGBT module IGBT1 and the bypass IGBT module IGBT2 are connected in series with a so-called reverse polarity.

  With the above-described configuration, when a failure occurs in the cell unit 100 including the first to fourth IGBT modules IGBTTU1 to IGBTTU4 configuring the above-described IGBT unit unit 130, the first to the first configuring the cell unit 100. The first bypass IGBT module IGBT1 and the second bypass IGBT module constituting the cell bypass unit 200 connected to the output terminal A or the output terminal B by turning off the gate G of the four IGBT modules IGBTTU1 to IGBTTU4 By turning on the gate G of the IGBT 2, the output of the cell unit 100 in which a failure has occurred can be short-circuited.

  The above-described processing is performed under the control of the control unit (not shown), and the cell unit 100 can be bypassed by turning on the bypass IGBT modules IGBT1 and IGBT2 constituting the cell bypass unit unit 200.

  In terms of physical arrangement, the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 constituting the first phase of the single phase output of the cell unit 100 and the second phase of the single phase output of the cell unit 100 are configured. The bypass IGBT module IGBT1 and the bypass IGBT module IGBT2 are arranged between the three IGBT modules IGBTTU3 and the fourth IGBT module IGBTTU4. Further, the output terminal (P1) of the first IGBT module and the output terminal (P2) of the second IGBT module are directed in the same direction, and the input terminal P5 of the first bypass IGBT module IGBT1 (the collector C of the IGBT1). And the output terminal (P3) of the third IGBT module and the output terminal (P4) of the fourth IGBT module are directed in the same direction, and the second bypass IGBT module IGBT2 Arranged to face the input terminal P6 (the collector C of the IGBT 2).

  FIG. 3 is a perspective view and a front view of the cell unit 100 before the present invention without the cell bypass unit 200 according to the first embodiment. FIG. 3 (1) is a perspective view of the cell unit 100, and FIG. ) Is a front view of the cell unit 100. The cell unit 100 shown in FIG. 3 shows a state where the cell bypass unit 200 is removed. Hereinafter, main connection states in the cell unit 100 will be described with reference to FIGS. 1 and 2.

  In addition, the connection of the rectifier diode part 110, the smoothing capacitor part 120, the IGBT unit part, etc. not directly related to the present invention is omitted.

  (1) The emitter E and the collector C of the two IGBTs constituting the first IGBT module IGBTTU1 are connected at a connection point P1 (see FIG. 2). Similarly, the emitter E and the connector C of each of the two IGBTs constituting the second IGBT module IGBTTU2, the third IGBT module IGBTTU3, and the fourth IGBT module IGBTTU4 are connected at connection points P2, P3, and P4.

  (2) P1 of the first IGBT module IGBTTU1 and P2 of the second IGBT module IGBTTU2 constituting the first phase of the single-phase output of the cell unit 100 are connected, and further, the output terminal A of the cell unit 100 is connected by the bus bar 151. Connected to.

  (3) P3 of the third IGBT module IGBTTU3 and P4 of the fourth IGBT module IGBTTU4 constituting the second phase of the single-phase output of the cell unit 100 are connected, and further, the output terminal B of the cell unit 100 is connected by the bus bar 152. Connected to.

  4A and 4B are a perspective view and a front view when the cell bypass unit 200 is mounted on the cell unit 100 according to the first embodiment. FIG. 4A is a perspective view of the cell unit 100, and FIG. 2 is a front view of a cell unit 100. FIG. In addition, the connection of the rectifier diode part 110, the smoothing capacitor part 120, the IGBT unit part, etc. not directly related to the present invention is omitted.

Hereinafter, main connection states in the cell unit 100 in a state where the cell bypass unit unit 200 is mounted will be described with reference to FIGS.

  (4) The emitters and collectors of the two IGBTs constituting the first IGBT module IGBTTU1 are connected at a connection point P1 (see FIG. 2). Similarly, the emitters and collectors of two IGBTs constituting the second IGBT module IGBTTU2, the third IGBT module IGBTTU3, and the fourth IGBT module IGBTTU4 are connected at connection points P2, P3, and P4.

  (5) P1 of the first IGBT module IGBTTU1 (output terminal of the IGBT unit) and P2 of the second IGBT module IGBTTU2 (output terminal of the IGBT unit) constituting the first phase of the single phase output of the cell unit 100 are connected. Furthermore, it is connected to the output terminal A of the cell unit 100 by the bus bar 151, and the collector C of the first bypass IGBT module IGBT1 of the cell bypass unit section 200 by the bus bar 201 (the first terminal of the cell bypass unit, P5).

  (6) P3 of the third IGBT module IGBTTU3 (output terminal of the IGBT unit) and P4 of the fourth IGBT module IGBTTU4 (output terminal of the IGBT unit) constituting the second phase of the single phase output of the cell unit 100 are connected. Furthermore, it is connected to the output terminal B of the cell unit 100 by the bus bar 152, and the collector C of the second bypass IGBT module IGBT2 of the cell bypass unit section 200 by the bus bar 202 (the first terminal of the cell bypass unit, P6).

  (7) The output voltage of the output terminal A and the output terminal B of the cell unit 100 described above is the output voltage of the first to fourth IGBT modules IGBTTU1 to IGBTTU4, and the connection modes (4) to (6) described above. Accordingly, the outputs (P1, P2) of the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 and the inputs of the bypass IGBT module IGBT1 (collector C, P5 of the IGBT1) face each other, and the bus bar 201 Connected with. Similarly, the output (P3, P4) of the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 and the input of the second bypass IGBT module IGBT2 (collector C, P6 of the IGBT2) face each other. And are connected by a bus bar 202.

  The feature of the present embodiment is that the outputs (P1, P2) of the first and second IGBT modules (IGBTU1 and IGBTTU2) and the input of the first bypass IGBT module IGBT1 (the collector C of the IGBT1) face each other. The bus bar 201 is arranged so that the outputs of the third and fourth IGBT modules (IGBTU3 and IGBTTU4) and the input of the second bypass IGBT module IGBT2 (collector C of the IGBT2) face each other. In addition, the wiring length of the bus bar 202 can be shortened, and the problem of increased inductance due to the wiring length can be solved.

  (8) Next, in the cell unit 100 according to the above (4) to (7), the first bypass IGBT module during normal operation and during a failure due to a short circuit of the IGBT or the like constituting the IGBT unit section 130 A method for operating the cell unit 100 by switching the use mode of the IGBT 1 and the second bypass IGBT module IGBT 2 by the switching means will be described.

  The control unit (not shown) has switching means for switching the use mode to the next mode a and mode b.

  The mode-a switching means turns off the cell bypass IGBT by controlling the two cell bypass IGBTs in the off state during normal operation, and performs PWM control of the IGBT unit unit 130 to control the IGBT unit unit 130. The output voltage is set as the output voltage of the cell unit 100. In this state, the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 are in the off state and there is almost no loss, so the IGBT unit section 130 is not affected by the heat generation.

  The mode b switching means controls the first to fourth by turning off the gates G of all IGBTs constituting the IGBT unit section 130 of the failed cell unit 100 when the cell unit 100 has a failure due to a direct current short circuit of the IGBT. By turning off the IGBT modules IGBTTU1 to IGBTTU4 and further controlling the gates G of the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 in the cell bypass unit section 200 of the failed cell unit 100 to be turned on With the cell bypass unit portion in the energized state, the output of the failed cell unit 100 is short-circuited. By performing the above processing, the IGBT unit section 130 is in the OFF state in mode b and there is almost no heat loss. Therefore, the first bypass IGBT module IGBT1 and the second bypass IGBT module IGBT2 generate heat. Not affected.

  As described above, the portion that generates heat during normal operation and the portion that generates heat during failure are different, so there is no concentration of heat sources, and the cooling performance of the heat sink is not reduced (the performance (cooling performance) of the heat sink 140 can be ensured) .)

  Further, the outputs (P1, P2) of the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 and the input of the first bypass IGBT module IGBT1 (collector C of the IGBT1) are arranged to face each other. By arranging the output of the IGBT module IGBTTU3 and IGBT4 of the third IGBT4 and the input of the IGBT module IGBT2 for bypass 2 (the collector C of the IGBT2) to face each other, the IGBT unit 130 and the cell bypass Since the bus connection length between the unit portions can be shortened, it is possible to provide the cell unit 100 in which the inductance can be reduced by the wiring length. In the present embodiment, the first IGBT module IGBTTU1 and the second IGBT module IGBTTU2 are connected in parallel, and the third IGBT module IGBTTU3 and the fourth IGBT module IGBTTU4 are connected in parallel. It is good also as a structure without.

  As described above, according to the present invention, it is possible to provide a cell unit capable of reducing inductance by making the shortest wiring between the IGBT unit and the cell bypass IGBT and reducing the size of the heat sink.

DR, DS, DT Rectifier diodes CF1 to CF10 Smoothing capacitor IGBTTU1 1st IGBT module IGBTTU2 2nd IGBT module IGBTTU3 3rd IGBT module IGBTTU4 4th IGBT module A, B Output terminal 100 Cell unit 110 Rectifier diode section 120 Smoothing Capacitor part 130 IGBT unit part 131, 132, 134, 135 Bus bar 151, 152 Bus bar 140, 140B Heat sink 200 Cell bypass unit IGBT1 First bypass IGBT module IGBT2 Second bypass IGBT module 201, 202 Bus bar 300 Conventional cell unit

Claims (4)

A single-phase output cell unit constituting a large capacity inverter,
An IGBT unit constituting the first phase;
An IGBT unit constituting the second phase;
A cell bypass unit that short-circuits the output of the cell unit;
An IGBT module constituting the IGBT unit constituting the first phase on one air-cooled heat sink, an IGBT module constituting the IGBT unit constituting the second phase, and an IGBT module constituting the cell bypass unit It is fixed tightly
The cell bypass unit is
Arranged between the IGBT unit constituting the first phase and the IGBT unit constituting the second phase,
The output terminal of the IGBT unit constituting the first phase and the first terminal of the cell bypass unit are arranged to face each other,
The output terminal of the IGBT unit constituting the second phase and the second terminal of the cell bypass unit are arranged to face each other,
The output terminal of the IGBT unit constituting the first phase and the first terminal of the cell bypass unit are connected by a bus bar,
An output terminal of an IGBT unit constituting the second phase and a second terminal of the cell bypass unit are connected by a bus bar. The IGBT unit that constitutes the first phase, the IGBT unit that constitutes the second phase, and the cell bypass unit are tightly fixed on one air-cooled heat sink,
The use mode of the IGBT for cell bypass constituting the cell bypass unit is switched between the normal operation of the cell unit and the failure of the IGBT unit constituting the first phase or the IGBT unit constituting the second phase. Switching means,
The switching means is
During normal operation, by turning off the gate of the cell bypass IGBT that constitutes the cell bypass unit, the output voltage of the IGBT unit that constitutes the first phase and the IGBT unit that constitutes the second phase can be obtained. Unit output voltage,
When the IGBT unit constituting the first phase or the IGBT unit constituting the second phase fails, all the gates of the IGBT unit constituting the first phase and the IGBT unit constituting the second phase are turned off. 2. The cell unit according to claim 1, wherein the output of the cell unit is brought into a short-circuited state by turning on a gate of a cell bypass IGBT constituting the cell bypass unit. Arranging the IGBT units constituting the second phase in order from the upstream direction to the downstream direction in the ventilation direction,
Arranging the cell bypass unit;
The cell unit according to claim 1 or 2, wherein an IGBT unit constituting the first phase is arranged. An IGBT module constituting the IGBT unit constituting the first phase on one air-cooled heat sink;
An IGBT module constituting the IGBT unit constituting the second phase;
An IGBT module constituting the cell bypass unit;
The diode module constituting the rectifier diode part is closely fixed, and the rectifier diode part is arranged in order from the upstream direction to the downstream direction of the ventilation direction,
An IGBT unit constituting the second phase is arranged,
Arranging the cell bypass unit;
The cell unit according to claim 1 or 2, wherein an IGBT unit constituting the first phase is arranged.