2-in-1 type chopper module

Abstract

Chopper module (141, 142, 143) of the two-in-one type, comprising: - a switching transistor (103); - a first diode (104) which is connected in reverse parallel with the switching transistor (103); - a second diode (106) connected in series with the switching transistor (103) and the first diode (104); - a first wiring structure (115) to which the switching transistor (103) and the first diode (104) are attached; and - a second wiring structure (114) to which the second diode (106) is attached, wherein: - both the switching transistor (103) and the first diode (104) are configured to exhibit identical power losses at a time when a current is passed in the forward direction, - an effective area of ​​the second diode (106) is larger than an effective area of ​​the first diode (104), - the first diode (104) is constructed from one or a plurality of first diode elements (120), and - the second diode (106) is constructed from a parallel connection of a diode element (125) made of Si and a Schottky barrier diode element (126) made of a semiconductor with a wide band gap.

Description

Technical field

[0001] The present invention relates to a two-in-one type chopper module. Background technology

[0002] There is a semiconductor module, a semiconductor device used for power control. Examples of semiconductor modules include insulated-gate bipolar transistors (IGBTs). The IGBT module performs on / off control of a line current using a gate control signal and is capable of switching under high voltage and high current. A semiconductor power module containing an IGBT is widely used, for example, in an inverter that controls a motor.

[0003] A two-in-one semiconductor module can easily be mounted, for example, on a motor control device and is therefore in common use. A two-in-one semiconductor module typically comprises an IGBT module and a chopper module.

[0004] The two-in-one IGBT module consists of two circuits connected in series, each containing an IGBT element and a diode element connected in reverse parallel with the IGBT element. The IGBT element and the diode element are often mounted on an insulating substrate within the IGBT module. In normal inverter operation, a current of similar magnitude flows alternately through the IGBT element and the diode element, so each element is always generating heat, and the insulating substrate absorbs this heat from both elements.

[0005] A two-in-one chopper module has a configuration in which the IGBT element is removed from one of the two circuits connected in series within the module. Accordingly, the chopper module contains an insulating substrate on which only the diode element is mounted. In inverter operation, a current of similar magnitude must be alternately applied to the IGBT element and the diode element in the circuit containing the IGBT element and the diode element connected in reverse parallel with the IGBT element, so that the circuit has the same configuration as the IGBT module described above. The insulating substrate on which only the diode element is mounted receives less heat compared to an insulating substrate on which both the diode element and the IGBT element are mounted.

[0006] Patent document 1 discloses in Fig. 8 a step-up chopper circuit and a step-down chopper circuit as a conventional technique with a circuit configuration similar to that of the chopper module. State-of-the-art documents, patent documents

[0007] Patent document 1: Published Japanese patent application JP 2010-200406A

[0008] Publication US 2016 / 0126168A1 discloses a semiconductor device comprising a first substrate consisting of an electrical conductor, a first diode having a first cathode electrode and a first anode electrode, the first cathode electrode being electrically connected to the first substrate, a second substrate consisting of an electrical conductor, a first switching element having a first emitter electrode, a first collector electrode, and a first gate electrode, the first collector electrode being electrically connected to the second substrate, a second switching element having a second emitter electrode, a second collector electrode, and a second gate electrode, the second collector electrode being electrically connected to the second substrate, a first terminal being electrically connected to the second substrate, and a second terminal being electrically connected to the first anode electrode.a third terminal electrically connected to the first emitter electrode, the second emitter electrode and the first substrate, and a molding resin encasing the first substrate, the first diode, the second substrate, the first switching element and the second switching element, with areas of the first terminal, the second terminal and the third terminal exposed to the outside.

[0009] Publication US 2010 / 0213915A1 describes a semiconductor switching device with a power control section. This section comprises a voltage reduction circuit with a first switching element and a first diode, a voltage boost circuit with a second switching element and a second diode, and an inductor. The inductor is connected such that a special current caused by a short circuit in the switching branches is conducted through it. Summary Problem to be solved by the invention

[0010] Normally, the semiconductor module is placed in a heatsink and actively cooled. Consequently, the diode element mounted alone on the insulating substrate in the chopper module tends to have a lower temperature on the low-temperature side than the IGBT element or the diode element both mounted on the insulating substrate. Accordingly, the diode element mounted alone on the insulating substrate in the chopper module exhibits a large temperature difference between its high-temperature and low-temperature sides. As a result, a problem arises in the chopper module: the temperature cycle lifetime of the wiring on the diode element decreases.

[0011] The present invention was therefore made to solve the above problems, and it is an object of the present invention to suppress a reduction in the temperature cycle lifetime of the wiring in the two-in-one type chopper module. Means to solve the problem

[0012] The problem underlying the invention is solved according to the invention in a two-in-one type chopper module by the features of claim 1. An advantageous further development is the subject of dependent claim 2.

[0013] A two-in-one semiconductor module according to the present invention comprises: a switching transistor; a first diode connected in reverse parallel with the switching transistor; a second diode connected in series with the switching transistor and the first diode; a first wiring structure to which the switching transistor and the first diode are attached; and a second wiring structure to which the second diode is attached, wherein both the switching transistor and the first diode have substantially identical power losses during forward current transmission and an effective area of ​​the second diode is larger than an effective area of ​​the first diode.

[0014] According to the invention, the first diode is constructed from one or a plurality of first diode elements. The second diode, according to the invention, is constructed from a parallel connection of a diode element made of silicon and a Schottky barrier diode element made of a wide bandgap semiconductor. Effects of the invention

[0015] In the two-in-one semiconductor module according to the present invention, during inverter operation, a current of similar magnitude flows alternately through the switching transistor and the first diode, and the power loss therein is essentially the same. Accordingly, the insulating substrate to which the first wiring structure is attached always receives heat; however, the insulating substrate to which the second wiring structure is attached receives heat only when current is conducted to the second diode. If the cooling capacity of the two insulating substrates is equivalent, the temperature on the low-temperature side of the second diode will accordingly be lower than that of the first diode. However, the effective area of ​​the second diode is larger than that of the first diode, so the second diode generates less heat than the first diode and has a lower temperature on its high-temperature side.Accordingly, the temperature difference in the second diode decreases. As a result, the temperature cycle lifetime of the wiring connected to the second diode increases.

[0016] These and other tasks, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when it is carried out in conjunction with the accompanying drawings. Brief description of the drawings [ Fig. 1] A circuit diagram of a two-in-one type IGBT module. [ Fig. 2] A diagram of an internal configuration of the two-in-one type IGBT module. [ Fig. 3] A circuit diagram of a two-in-one type chopper module. [ Fig. 4] A diagram of an internal configuration of the two-in-one type chopper module. [ Fig. 5] A circuit diagram of a two-in-one type chopper module according to embodiment 1 to explain the further technical background of the present invention. [ Fig. 6] A diagram of an internal configuration of the two-in-one type chopper module according to embodiment 1 to explain the further technical background of the present invention. [ Fig. 7] A diagram of an internal configuration of a two-in-one type chopper module according to embodiment 2 to explain the further technical background of the present invention. [ Fig. 8] A diagram of an internal configuration of a two-in-one type chopper module according to an embodiment of the invention 3. Description of one embodiment(s)<A. Zugrundeliegende Technik>

[0017] Fig. Figure 1 is a circuit diagram of a two-in-one IGBT module 100, which is an underlying technique of the present invention. The two-in-one IGBT module 100 consists of a circuit 101 and a circuit 102 connected in series. Circuit 101 comprises an IGBT 103 and a diode 104 connected in inverse parallel with the IGBT 103. Circuit 102 comprises an IGBT 105 and a diode 106 connected in inverse parallel with the IGBT 105. The IGBTs 103 and 105 are made, for example, of silicon.

[0018] Three electrodes – a P-type main electrode 107, an N-type main electrode 108, and an AC-type main electrode 109 – form a main electrode of the two-in-one IGBT module 100. The P-type main electrode 107 is connected to a collector of the IGBT 105 and a cathode of the diode 106. The AC-type main electrode 109 is connected to a junction between circuit 101 and circuit 102. The N-type main electrode is connected to an emitter of the IGBT 103 and an anode of the diode 104.

[0019] Fig. Figure 2 is a planar schematic view illustrating the internal structure of the IGBT module 100, a two-in-one type. For a simplified description of the internal structure, gate wiring, measurement wiring, and a package are shown, for example. Fig. 2 not illustrated.

[0020] In Fig. Insulating substrates 111, 112, and 113 are arranged on a base plate 110. Wiring structures 114, 115, and 116 are formed on the insulating substrates 111, 112, and 113, respectively. The in Fig. 1. The illustrated circuit 102 is formed on the wiring structure 114, and the one in Fig. The illustrated circuit 101 is formed on the wiring structure 115. Specifically, three IGBT elements 117 and three diode elements 118 are arranged on the wiring structure 114 by means of solder connections. Three IGBT elements 119 and three diode elements 120 are arranged on the wiring structure 115 by means of solder connections.

[0021] The three IGBT elements 117 form the IGBT 105 in Fig. 1, and the three diode elements 118 form the diode 106 in Fig. 1. The three IGBT elements 119 form the IGBT 103 in Fig. 1, and the three diode elements 120 form the diode 104 in Fig. 1.

[0022] An aluminum wiring assembly 121 establishes a connection between a surface electrode of the IGBT element 117 and a surface electrode of the diode element 118, and between the surface electrode of the diode element 118 and the wiring structure 115. An aluminum wiring assembly 122 establishes a connection between a surface electrode of the IGBT element 119 and a surface electrode of the diode element 120, and between the surface electrode of the diode element 120 and the wiring structure 116. The aluminum wiring assemblies 121 and 122 are described herein; however, wiring made of a different material, such as copper, can also be used.

[0023] The P main electrode 107, the AC main electrode 109 and the N main electrode 108 are connected to the wiring structures 114, 115 and 116 respectively.

[0024] In inverter operation, essentially the same current flows alternately in an inverse direction through two types of elements formed on the same insulating substrate, namely the IGBT element 117 and the diode element 118, or the IGBT element 119 and the diode element 120, and each element generates heat. These two types of elements are designed to exhibit essentially the same power loss when conducting current in the forward direction, so that they have essentially the same maximum chip temperature.

[0025] Fig. Figure 3 is a circuit diagram of a two-in-one type chopper module 130, which is an underlying technology of the present invention. The two-in-one type chopper module 130 comprises the circuit 101 and the diode 106 connected in series with the circuit 101. In other words, the two-in-one type chopper module 130 has a configuration in which the IGBT 105 from the circuit 102 in the two-in-one type IGBT module 100 is omitted.

[0026] Fig. Figure 4 is a planar schematic view illustrating the internal structure of the two-in-one type chopper module 130. For a simplified description of the internal structure, gate wiring, measurement wiring, and a housing are shown, for example. Fig. 4 not illustrated.

[0027] The internal configuration of the in Fig. The 4 illustrated chopper module 130 of the two-in-one type is from the internal configuration of the in Fig. The IGBT module 100 of the two-in-one type, as illustrated in Figure 2, differs in that the three IGBT elements 117 are not formed on the wiring structure 114 on the insulating substrate 111, but only the three diode elements 118 are formed there. Similarly, in the chopper module 130 of the two-in-one type, it is necessary in inverter operation to allow essentially the same current to flow alternately in the reverse direction through the IGBT 103 and the diode 104, so that the configuration on the insulating substrates 112 and 113 is essentially similar to that of the IGBT module 100 of the two-in-one type.

[0028] The two-in-one chopper module 130 is obtained by removing the IGBT 105 from the two-in-one IGBT module 100, thus offering the advantage that no new component or manufacturing process is required. Accordingly, the two-in-one chopper module 130 is widely used, for example, in three-level circuits.

[0029] In inverter operation of the two-in-one chopper module 130, the current flows alternately through the IGBT 103 and the diode 104. Accordingly, the insulating substrate 112 always receives heat from either the IGBT element 119 or the diode element 120. However, only one diode element 126 is mounted on the insulating substrate 111, and the IGBT element is not. The magnitude of the current flowing in the diode element 126 is essentially the same as that flowing in either the IGBT element 119 or the diode element 120; however, heat is generated in the insulating substrate 111 only when the current is directed to the diode element 126. Consequently, the insulating substrate 111 receives a small amount of heat compared to the insulating substrate 112.

[0030] The semiconductor module is normally placed in a heat sink and actively cooled, so that, if the cooling capacity for the insulating substrates 111 and 112 is equivalent, the low-temperature side temperature of the diode element 126 mounted on the insulating substrate 111 tends to be lower during inverter operation than that of the IGBT element 119 or the diode element 120 mounted on the insulating substrate 112. If the diode elements 120 and 126 have the same high-temperature side temperature when current is conducted, the temperature difference between the low and high temperatures in the diode element 126 is greater than that in the diode element 120.The temperature cycle lifetime of the aluminum wiring is reduced when the temperature difference increases, so there is a problem that the temperature cycle lifetime of the aluminum wiring 121 on the diode element 126 is reduced due to the increase in the temperature difference in the diode element 126. <B. Ausführungsform 1 zum technischen Hintergrund><B-1. Konfiguration>

[0031] Fig. Figure 5 is a circuit diagram of a two-in-one type chopper module 141 according to embodiment 1, to explain the further technical background of the present invention. The circuit diagram of the two-in-one type chopper module 141, which is shown in Figure 5, is a diagram of the two-in-one type chopper module 141. Fig. The illustration in section 5 is similar to that of the one in Fig. 3 illustrated chopper module 130 of the two-in-one type.

[0032] Fig. Figure 6 is a diagram of the internal configuration of the two-in-one type chopper module 141. Gate wiring, measurement wiring, and a housing, for example, are shown for a simplified description of the internal structure. Fig. 6 not illustrated. In the two-in-one type chopper module 141, three diode elements 123 are arranged on the wiring structure 114 by means of a solder connection instead of the three diode elements 118, and the other configuration is similar to the internal configuration of the one in Fig. 4 illustrated chopper module 130 of the two-in-one type. The three diode elements 123 form the diode 106 in Fig. 5.

[0033] Diode element 123 has a large effective area per element compared to diode element 120. The number of diode elements 123 is the same as the number of diode elements 120. Accordingly, the total effective area of ​​all diode elements 123 mounted on the insulating substrate 111 is larger than that of all diode elements 120 mounted on the insulating substrate 112.

[0034] The number of diode elements 123 and diode elements 120 is not based on the one in Fig. Figure 6 illustrated three limited uses; however, one or more diode elements can also be used, as long as their number is the same.

[0035] The IGBT element 119 and the diode element 120, mounted on the insulating substrate 112, are designed to exhibit substantially the same power loss, such that they have substantially the same maximum chip temperature when substantially the same current flows alternately in reverse direction through those elements. If there is a difference between the maximum chip temperatures in those elements, a difference in the temperature cycle lifetime of the aluminum wiring in those elements will occur, such that the difference between the maximum chip temperatures is preferably 20% or less.

[0036] Normally, the semiconductor module is placed in a heat sink and actively cooled. In inverter operation of the two-in-one chopper module 141, current flows through both the IGBT element 119 and the diode element 120, and heat is generated on the insulating substrate 112; however, heat is only generated on the insulating substrate 111 when current is directed to the diode element 123. Consequently, the insulating substrate 111 has a longer cooling time during which no heat is generated than the insulating substrate 112. Thus, the diode element 123 has a lower temperature on its low-temperature side than both the IGBT element 119 and the diode element 120.

[0037] In the present embodiment, however, the diode element 123 has a larger effective area than the diode element 120, so that it generates less heat when the same current is conducted. Consequently, the diode element 123 has a lower maximum temperature than the diode element 120. Accordingly, the temperature difference between the high and low temperatures in the diode element 123 is reduced, and a reduction in the temperature cycle life of the aluminum wiring 121 on the diode element 123 can be prevented.

[0038] One in Fig. The chopper circuit illustrated in patent document 1 is the one described in Fig. The chopper semiconductor module 141 of the two-in-one type, illustrated as a circuit diagram in Figure 5 of the present patent description, is similar. Fig. However, the chopper circuit illustrated in patent document 1 has a configuration in which a small diode is connected in reverse parallel with a switching element to prevent a momentary application of an inverse voltage to the switching element. The current, which is similar to that in the switching element, cannot be conducted to the inverse parallel diode and thus has a characteristic similar to that of the chopper circuit of the two-in-one type chopper module 141, illustrated in Fig. 1 in patent document 1, various uses. <B-2. Modifikationsbeispiel>

[0039] In the description above, the silicon-based IGBT is used for the switching transistor that forms the two-in-one chopper module; however, a wide-bandgap silicon-based element, for example, could be used for the switching transistor. Accordingly, the switching loss of the switching transistor can be reduced.

[0040] For example, a wide-bandgap SiC element can be used for diode 104. Accordingly, the recovery loss of diode 104 can be reduced.

[0041] For example, a wide-bandgap SiC element can be used for diode 106. Accordingly, conduction loss in diode 106 can be reduced.

[0042] A suitable material for the switching transistor or diode can be selected to obtain optimal characteristics according to the intended use of the two-in-one type chopper module.

[0043] In Fig. 5 the cathode of diode 106 is connected to the P main electrode 107, and an anode is connected to the AC main electrode 109; however, their direction may be reversed according to a circuit configuration to be used.

[0044] In Fig. In Figure 5, the circuit 101, consisting of the IGBT 103 and the diode 104, is connected between the AC main electrode 109 and the N main electrode 108; however, this configuration is only an example. The circuit 101 can also be connected between the P main electrode 107 and the AC main electrode 109.

[0045] Furthermore, the three insulating substrates are included in the above description; however, the number of insulating substrates is not limited to three, as long as each wiring structure is electrically independent of the others.

[0046] The modification example described herein can also be used for embodiment 2 to explain the further technical background of the present invention and for embodiment 3 according to the invention, which are described below. <B-3. Effekt>

[0047] The two-in-one type chopper module 141 according to embodiment 1, for technical background, comprises the IGBT 103, which is the switching transistor, the diode 104, which is a first diode connected in reverse parallel with the IGBT 103, the diode 106, which is a second diode connected in series with the IGBT 103 and the diode 104, the wiring structure 115, which is a first wiring structure to which the IGBT 103 and the diode 104 are attached, and the wiring structure 114, which is a second wiring structure to which the diode 106 is attached. The power loss during a current flow in the forward direction to the IGBT 103 and the diode 104 is essentially the same, so that the temperature on the low-temperature side of the diode 106 in inverter operation is lower than that of the IGBT 103 and the diode 104.However, the effective area of ​​diode 106 is larger than that of diode 104, so the amount of heat generated in diode 106 at the time the same current is conducted can be less than in diode 104. As a result, diode 106 has a lower maximum temperature than diode 104. Consequently, the temperature difference between the high and low temperatures in diode 106 decreases, and a reduction in the temperature cycle life of the aluminum wiring 121 on diode 106 can be prevented.

[0048] In the two-in-one type chopper module 141, the first diode 104 is constructed from diode element 120, which is one or a plurality of first diode elements, and the second diode 106 is constructed from diode element 123, which is a second diode element, the number of which is the same as that of diode element 120. The effective area of ​​diode element 123 per element is larger than that of diode element 120 per element. Accordingly, the total effective area of ​​the diode elements 123 mounted on the insulating substrate 111 is larger than that of the diode elements 120 mounted on the insulating substrate 112. As a result, diode element 123 has a lower maximum temperature than diode element 120.Accordingly, the temperature difference between the high temperature and the low temperature in the diode element 123 decreases, and a reduction in the temperature cycle lifetime of the aluminium wiring 121 on the diode element 123 can be prevented. <C. Ausführungsform 2 zum technischen Hintergrund><C-1. Konfiguration>

[0049] Fig. Figure 7 is a diagram of an internal configuration of a two-in-one type chopper module 142 according to embodiment 2, to illustrate the further technical background of the present invention. A circuit diagram of the two-in-one type chopper module 142 is shown in Figure 7. Fig. Figure 5 illustrates and is the same as that of the two-in-one type chopper module 141 according to embodiment 1 for technical background.

[0050] To easily describe the internal structure, for example, gate wiring, measurement wiring, and a housing are included. Fig. 7 not illustrated.

[0051] In the configuration of the two-in-one type chopper module 142, the configuration on the wiring structure 114 on the insulating substrate 111 differs from that of the two-in-one type chopper module 141 according to embodiment 1 for technical background, while the other configuration is similar to that of the two-in-one type chopper module 141. Therefore, only the configuration on the wiring structure 114 will be described below.

[0052] In the two-in-one type chopper module 142, five diode elements 124 are arranged on the wiring structure 114 on the insulating substrate 111. That is, in the two-in-one type chopper module 142, the five diode elements 125 form the diode 106 in Fig. 5.

[0053] The three diode elements 120 are arranged on the wiring structure 115 on the insulating substrate 112, and the number of diode elements 124 is greater than the number of diode elements 120. Diode element 124 and diode element 120 are identical diode elements and have the same effective area per element. Consequently, the total effective area of ​​all diode elements 124 on the wiring structure 114 is greater than that of all diode elements 120 on the wiring structure 115. Accordingly, the effective area of ​​diode 106 is greater than that of diode 104.

[0054] In Fig. 7 the number of diode elements is 124 five, but is not limited to five as long as it is greater than the number of diode elements 120.

[0055] In a manner similar to embodiment 1 (see technical background), heat is generated on the insulating substrate 111 only when current is directed to the diode element 124, so that a period of heat generation on it is shorter than that on the insulating substrate 112, in which the IGBT element 119 and the diode element 120 alternately generate heat. Thus, the diode element 124 has a lower temperature on the low-temperature side than the IGBT element 119 and the diode element 120.

[0056] In the present embodiment, the total effective area of ​​the five diode elements 124 is larger than that of the three diode elements 120. Therefore, when the same current is conducted, the amount of heat generated in the five diode elements 124 is less than that generated in the three diode elements 120. Consequently, the diode element 124 has a lower maximum temperature than the diode element 120. Accordingly, the temperature difference between the high and low temperatures in the diode element 124 is reduced, and a reduction in the temperature cycle life of the aluminum wiring 121 on the diode element 124 can be prevented. <C-2. Effekt>

[0057] In the chopper module 142 of the two-in-one type according to embodiment 2, for technical background, the diode 104, which is the first diode, is constructed from the diode element 120, which is one or the plurality of first diode elements; the diode 106, which is the second diode, is constructed from the diode element 124, which is the second diode element, which is numerically larger than the diode element 120; and the effective area of ​​the diode element 124 per element is equal to the effective area of ​​the diode element 120 per element. Accordingly, the total effective area of ​​all the diode elements 124 mounted on the insulating substrate 111 is larger than that of all the diode elements 120 mounted on the insulating substrate 112. Thus, the amount of heat generated in all the diode elements 124 mounted on the insulating substrate 111 is smaller than that in all the diode elements 120 mounted on the insulating substrate 112.Consequently, the diode element 124 has a lower maximum temperature than the diode element 120. Accordingly, the temperature difference between the high temperature and the low temperature in the diode element 124 decreases, and a reduction in the temperature cycle lifetime of the aluminum wiring 121 on the diode element 124 can be prevented. <D. Erfindungsgemäße Ausführungsform 3><D-1. Konfiguration>

[0058] Fig. Figure 8 is a diagram of an internal configuration of a two-in-one type chopper module 143 according to an embodiment 3 of the invention. A circuit diagram of the two-in-one type chopper module 143 is shown in Figure 8. Fig. Figure 5 illustrates and is similar to that of the two-in-one type chopper module 141 according to embodiment 1 for technical background.

[0059] For a simple description of the internal structure, in Fig. Figure 8, for example, does not illustrate gate wiring, measuring wiring, and a housing.

[0060] In the configuration of the two-in-one type chopper module 143, the configuration on the wiring structure 114 on the insulating substrate 111 differs from that of the two-in-one type chopper module 141 according to embodiment 1 for technical background, while the other configuration is similar to that of the two-in-one type chopper module 141. Consequently, only the configuration on the wiring structure 114 will be described below.

[0061] The three silicon diode elements 125 and the four silicon carbide (SiC) Schottky barrier diode elements 126 are arranged on the wiring structure 114. That is, in the two-in-one type chopper module 143, the parallel connection of the three diode elements 125 and the four Schottky barrier diode elements 126 forms the diode 106 in Fig. 5. In the above description, the Schottky barrier diode element 126 is made of SiC; however, another wide bandgap semiconductor can be used as the material.

[0062] Diode 106 has a larger effective area than diode 104. Accordingly, the total effective area of ​​the diode elements 125 and the Schottky barrier diode elements 126 is configured to be larger than that of the diode elements 120 arranged on the wiring structure 115. The conduction loss of diode 106 is lower than that of diode 104. As long as this condition is met, the number of diode elements 125 and Schottky barrier diode elements 126 is not limited to the number shown in Fig. Figure 8 illustrates this to a limited extent; however, one or more of these can also be used. In the description above, the effective area of ​​diode element 125 per element is equal to the effective area of ​​diode element 120 per element. Fig. 8, but can also be larger or smaller than the effective area of ​​the diode element 120 per element. In the description above, the effective area of ​​the Schottky barrier diode element 126 per element is smaller than the effective area of ​​the diode element 120 per element. Fig. 8, but can also be equal to, or greater than, that of diode element 120. <D-2. Effekt>

[0063] In the two-in-one type chopper module 143 according to embodiment 3 of the invention, the diode 104, which is the first diode, is constructed from the diode element 120, which is one or a plurality of first diode elements, and the parallel connection of the silicon-based diode element 125 and the Schottky barrier diode element 126, made from a wide-bandgap semiconductor, forms the diode 106, which is the second diode. In the diode element 125 and the Schottky barrier diode element 126, the number and effective area per element are not particularly limited. However, the total effective area of ​​the diode element 125 and the Schottky barrier diode element 126, that is, the effective area of ​​the diode 106, is larger than the total effective area of ​​the diode element 120, that is, the effective area of ​​the diode 104.Thus, similar to embodiment 1 (see technical background), the diode element 125 and the Schottky barrier diode element 126 have a lower maximum temperature than the diode element 120. Accordingly, the temperature difference between the high and low temperatures in the diode element 125 and the Schottky barrier diode element 126 decreases, and a reduction in the temperature cycle lifetime of the aluminum wiring on these diode elements can be prevented.

[0064] The Schottky barrier semiconductor element 126, created from a wide-bandgap semiconductor, exhibits low conduction loss over a small current range. The silicon diode element 125, created from silicon, has low conduction loss over a large current range and high peak current withstand capability. Accordingly, the two-in-one chopper module 143 is configured to be a module with low loss and high peak current withstand capability.

[0065] In the configuration above, the IGBT is used for the two-in-one switching transistor forming the chopper module. However, a reverse-conducting transistor, such as a silicon IGBT for reverse conduction or a MOSFET, can also be used for the switching transistor. If the switching transistor is switched on when current flows forward to diode 104, current also flows through the reverse-conducting transistor, so that, compared to the case where current is only directed to diode 104, the voltage drop across the entire circuit 101 can be kept small.

[0066] In this case, the effective area of ​​diode 106 in circuit 102 is set up larger than the effective area of ​​diode 104, as described above. However, the total effective area of ​​diode 106 is set to such a large extent that the conduction loss of diode 106 in circuit 102 is smaller than the conduction loss of the entire circuit 101 when the transistor for reverse conduction is switched on at the time of forward conduction to diode 104, thus preventing a reduction in the temperature cycle lifetime of the aluminum wiring on diode 106. Explanation of reference symbols

[0067] 100 Two-in-one IGBT module, 101, 102 Circuit, 103, 105 IGBT, 104, 106 Diode, 107 P main electrode, 108 N main electrode, 109 AC main electrode, 110 Base plate, 111, 112, 113 Insulating substrate, 114, 115, 116 Wiring structure, 117, 119 IGBT element, 118, 120, 123, 124, 125 Diode element, 121, 122 Aluminum wiring, 126 Schottky barrier diode element, 130, 141, 142, 143 Two-in-one chopper module

Claims

[1] Chopper module (141, 142, 143) of the two-in-one type, comprising: - a switching transistor (103); - a first diode (104) which is connected in reverse parallel with the switching transistor (103); - a second diode (106) connected in series with the switching transistor (103) and the first diode (104); - a first wiring structure (115) to which the switching transistor (103) and the first diode (104) are attached; and - a second wiring structure (114) to which the second diode (106) is attached, wherein: - both the switching transistor (103) and the first diode (104) are configured to exhibit identical power losses at a time when a current is passed in the forward direction, - an effective area of ​​the second diode (106) is larger than an effective area of ​​the first diode (104), - the first diode (104) is constructed from one or a plurality of first diode elements (120), and - the second diode (106) is constructed from a parallel connection of a diode element (125) made of Si and a Schottky barrier diode element (126) made of a semiconductor with a wide band gap. [2] Chopper module (141, 142, 143) according to claim 1, wherein: - the switching transistor (103) is constructed from a reverse-conducting transistor, and - the module (141, 142, 143) is configured such that a voltage drop in the second diode (106) is smaller than a voltage drop in the reverse-conducting transistor (103) and the first diode (104) if a current is passed to both the reverse-conducting transistor (103) and the first diode (104) in a reverse-conducting state.

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