JP2932140B2 - Inverter for electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter for electric vehicles, and more particularly to an inverter suitable for electric vehicles such as electric trains and electric locomotives.

[0002]

2. Description of the Related Art As a power system for driving an electric vehicle,
A method in which an induction motor is driven at a variable speed by an inverter device has been put to practical use.

[0003] Such an electric vehicle inverter device, for example, in the case of a train in which electric motors are dispersed on a plurality of axles, must be fitted in a limited space under the floor. It is requested to do. Similarly, even in the case of an electric locomotive, in order to increase the total capacity of the inverter device group that can be mounted on one locomotive, there is a demand for reducing the size of each inverter device.

Conventionally, a semiconductor switch element of an inverter main circuit for driving an electric vehicle is disclosed in Japanese Utility Model Laid-Open Publication No. 2-753838 or literature: GTO-Stromrichter fuer Bahnen: SIEMENS,
Sonderdruck ausZEV-Glasers Annalen113 (1989) Nr. 6/7
juni / juli, pages 259-272)
A gate turn-off thyristor (GTO thyristor) is used. The reason is that the GTO thyristor has a relatively large withstand voltage and current capacity as compared with other semiconductor switch elements such as a bipolar transistor (BT) and a gate insulating bipolar transistor (IGBT), so that the inverter main circuit can be downsized. Because.

[0005] Conventionally, in order to reduce harmonic components of an output waveform, the above document (GTO-Stromrichter fuer Bahne) has been proposed.
As described in n), a so-called three-level switch for switching a three-level DC voltage to generate an AC output.
Inverters (or also referred to as neutral clamp inverters) have been proposed. In this three-level inverter, a main circuit for one phase of the inverter includes a pair of DC input terminals connected to a DC power supply, a neutral terminal connected to a neutral point of the DC power supply, and a pair of DC input terminals. A series connection circuit of first to fourth semiconductor switch elements connected between terminals,
Clamp diodes connected between the connection point of the first and second semiconductor switch elements and the neutral terminal, and between the connection point of the third and fourth semiconductor switch elements and the neutral terminal, respectively. And an AC output terminal connected to a connection point between the second and third semiconductor switch elements.

On the other hand, since the GTO thyristor has a large switching loss, the GTO thyristor is formed in a disk shape in order to enhance the cooling efficiency, and both surfaces of the disk are used as main electrodes, as described in the above-mentioned publications and literatures. A cooler having a configuration in which a conductive cooling block is pressed against each of the main electrodes and a boiling refrigerant is sealed inside the cooling block is used. As the refrigerant, an insulating refrigerant is used to ensure insulation between the cooling blocks on both sides of the GTO thyristor and between the refrigerant condensing part and the GTO thyristor. Conventionally, Freon having excellent cooling performance and insulating properties has been mainly used as a refrigerant satisfying such requirements.

[0007]

However, the above prior art has the following problems to be solved. That is, GT
O-thyristors cannot be used at a high switching frequency because of a large switching loss of an element and a large capacitance of a snubber capacitor and a snubber resistor for suppressing a voltage rise at the time of turn-off. The frequency is at most about 500 Hz. Therefore, if the inverter device for driving the motor is configured using the GTO thyristor, there is a limit in reducing the harmonic distortion of the output waveform even if the above-described three-level inverter is used. There is a problem that the electromagnetic noise is large.

Therefore, a semiconductor switch element (hereinafter, referred to as a high-frequency semiconductor switch element) that can be driven by a high-frequency pulse gate signal, such as a bipolar transistor capable of increasing the switching frequency, a gate-insulated bipolar transistor (IGBT), and a thyristor controlled by a MOS gate. Collectively) may be applied.

However, these devices used as high-frequency semiconductor switching devices generally have a low withstand voltage level (for example, general-purpose IGBTs have a 1200-V level), and are therefore not suitable for electric vehicles with an overhead line voltage of 1500 V DC. It cannot be applied as it is. Further, since high-frequency semiconductor switch elements in practical use generally have a relatively small current capacity, when they are applied to a large-capacity inverter device for an electric vehicle (for example, for driving a motor having a single unit capacity of 200 kW or more), A plurality of elements are connected in parallel and used.

Therefore, when applying a high-frequency semiconductor switch element such as an IGBT to an inverter device for an electric vehicle, the size of the inverter main circuit tends to be large. Miniaturization is required.

[0011] From the viewpoint of prevention of chlorofluorocarbon pollution, it is required to adopt a cooling system alternative to the chlorofluorocarbon boiling cooling system.

It is an object of the present invention to provide an inverter for an electric vehicle that uses a semiconductor switch element that can be driven at a higher frequency than a GTO thyristor and that can be downsized as a whole.

[0013]

In order to achieve the above object, an inverter device for an electric vehicle according to the present invention comprises a main circuit of each phase constituting an inverter having a pair of DC input terminals connected to a DC power supply. A neutral terminal connected to a neutral point of the DC power supply, a series connection circuit of first to fourth semiconductor switch modules connected between the pair of DC input terminals, And a clamp diode respectively connected between the connection point of the semiconductor switch module and the connection point of the third and fourth semiconductor switch modules and the neutral terminal, and the second and third semiconductor switch modules. And an AC output terminal connected to the connection point of the electric vehicle, wherein the first to fourth semiconductor switch modules are each G
A semiconductor switch element that can be driven at a higher frequency than the TO thyristor is mounted on a substrate having heat conductivity via an insulating member, and one of the first and fourth semiconductor switch modules and the second and third semiconductor switch modules are mounted. One of the semiconductor switch modules is combined and classified into two pairs, each pair is attached to a common heat receiving plate, and cooling means for cooling the heat receiving plate is thermally connected to the heat receiving plate. I do.

In this case, any one of a bipolar transistor, a gate-insulated bipolar transistor, and a thyristor controlled by a MOS gate can be selected as the semiconductor switch element.

Further, the two pairs of semiconductor switch modules may be mounted on separate heat receiving plates for each pair, or may be entirely mounted on the same heat receiving plate. Furthermore, a separate heat receiving plate may be formed for each phase of the inverter, or a common heat receiving plate may be used for each phase of the inverter.

It is preferable that the heat receiving plate be detachably attached to an opening formed in a vertical outer wall of a housing for hermetically housing components of the inverter, with the surface on which the semiconductor switch module is attached being on the inside. In this case, it is preferable to arrange the semiconductor switch modules attached to the heat receiving plate in the order in which they are connected in series.

Preferably, the cooling means is formed by attaching a radiation fin to a part of the heat transfer member, and the heat transfer member is integrally attached to each heat receiving plate from the viewpoint of miniaturization. As the heat transfer member, a heat pipe is preferable. A part of the heat pipe is embedded in the heat receiving plate, and a radiation fin is attached to an exposed portion of the heat pipe to serve as a cooling unit. Further, radiation fins may be directly mounted on the surface of the heat receiving plate opposite to the surface on which the semiconductor switch module is mounted.
In this case, the radiation fins can be formed integrally with the heat receiving plate.

[0018]

According to the present invention, the above objects can be achieved by the following operations.

Basically, the present invention employs a three-level inverter circuit, so that harmonics can be reduced. In addition, since a semiconductor switch element that can be driven at a higher frequency than the GTO thyristor is used, the switching frequency can be increased to reduce harmonics and output current ripple. Thereby, the electromagnetic noise can be further reduced. In addition, as a high frequency semiconductor switch element, for example, IGBT
Is used, the switching frequency is set to 500 to 3 kHz.
It is preferable to select within the range of z. When a bipolar transistor is used, the frequency can be set to 1 kHz or more.

The loss (heat generation) of the first to fourth semiconductor switch elements forming the three-level inverter main circuit is as follows:
It changes in relation to the operation mode (powering, coasting, braking) of the electric vehicle motor. It has been found that the loss of the first and fourth semiconductor switching elements has a peak during power running, and the loss of the second and third semiconductor switching elements has a peak during braking. Therefore, the first and second or third and fourth semiconductor switch modules having different loss peaks are mounted on a common heat receiving plate, and a cooler is mounted on the heat receiving plate to reduce the heat load of the cooler. It can be averaged over time. As a result, the cooler can be downsized, which can contribute to downsizing of the entire apparatus.

Further, according to the semiconductor switch module formed by mounting the free wheeling diode on the same substrate as the semiconductor switch element and attaching the semiconductor switch module to the heat receiving plate, heat is generated. Since the semiconductor element and its cooling system can be integrated, it can contribute to downsizing of the entire device.

Further, if the clamp diode is mounted on the same heat receiving plate as the semiconductor switch module, the heat generating semiconductor element and its cooling system can be further integrated, thereby contributing to downsizing of the entire device.

On the other hand, a semiconductor switch element and a freewheeling diode constituting a semiconductor switch module were mounted on a substrate via an insulating member. In other words, the insulation member is configured to secure the ground insulation of the semiconductor switch element and the like inside the module. Therefore, the heat receiving plate on which the semiconductor switch module is mounted can be grounded, and it is not necessary to take ground insulation of the heat receiving plate and the cooler thermally connected to the heat receiving plate, so that the configuration of the cooling system can be simplified and the entire device can be downsized. To contribute.

Further, since the heat receiving plate can be grounded, a heat pipe having a simple structure using water as a refrigerant can be applied as a heat transfer member for thermally connecting the heat receiving plate and the cooler, thereby ensuring the cooling performance. No need to use harmful CFCs.

Further, since the heat receiving plate can be grounded, the heat receiving plate can be directly attached to a housing for hermetically housing the inverter components. Then, if the heat receiving plate is detachably attached to the opening formed in the outer wall of the housing, the heat receiving plate is exposed outside the housing. As a result, the exposed surface of the heat receiving plate also effectively acts as a heat radiating surface, so that it is possible to suppress the temperature rise inside the housing as compared with the case where the heat receiving plate is installed in the housing as in the conventional case, and furthermore, to cool down. The heat radiation capacity of the vessel can be reduced and the size can be reduced.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. An inverter device for a train according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a main part for one phase of a train inverter device, and FIG. 2 is an arrow II-II of FIG.
3A is an enlarged view showing the arrangement of the semiconductor switch module and the clamp diode on the heat receiving plate, and FIG. 3B is a view showing the electrical connection between the semiconductor switch module and the clamp diode. 4 is a perspective view of the semiconductor switch module according to the present embodiment with a part cut away, FIG. 5 is an overall system configuration diagram of a train inverter device of the present embodiment, and FIG. 6 is an inverter for one phase. It is a block diagram of a main circuit.

First, with reference to FIG. 5 and FIG. 6, an overall configuration of a train inverter device of the present embodiment and an inverter main circuit will be described. As shown in FIG. 5, the train drive device to which the train inverter device of the present embodiment is applied is 4
It has an induction motor M ₁ , M ₂ , M ₃ , M ₄ . For these four induction motors, two
Inverter devices 1A and 1B are provided,
A drives the induction motors M ₁ and M ₂ , and the inverter 1B drives the induction motors M ₃ and M ₄ . Each inverter 1A, B is an inverter main circuit of each of the three phases, is configured to include a power unit PU ₁ to PU ₃ obtained by dividing for each phase. One DC input terminal of each of the power units PU _{1 to} PU ₃ is connected to the pantograph 2 via a circuit breaker 3, open switches 4A and B, and filter reactors 5A and B, and the other DC input terminal is grounded. .

As shown in FIG. 6, a so-called three-level inverter circuit is applied to the main circuit of each of the power units PU _{1 to} PU ₃ . FIG. 6 shows a main circuit for one phase of the inverter. Among a pair of DC input terminals P and N, P is connected to a DC line connected to the pantograph 2 in FIG. 3, and N is grounded. . A series circuit of _two filter capacitors CF ₁ and CF ₂ is connected to the pair of DC input terminals P and N, and a connection point between the filter capacitors CF ₁ and CF ₂ is a neutral point of the DC power source and a neutral point. Connected to terminal O. A series circuit of _four semiconductor switch modules SM _{1 to} SM ₄ is connected between a pair of DC input terminals P and N. Each of the semiconductor switch modules SM _{1 to} SM ₄ includes:
It is configured respectively by inverse parallel connection of the IGBT Q ₁ to Q ₄ and the freewheeling diode DF ₁ ~DF _4. Connection point of the semiconductor switch modules SM ₁ and SM connection point and the semiconductor switch modules SM _{3 2} and SM ₄ are
It is connected to the neutral point terminal O, respectively, via the clamp diode DC ₁ and DC _2. The connection point of the semiconductor switch modules SM ₂ and SM ₃ is connected to the AC output terminal M.

The snubber circuit includes a snubber capacitor CS ₁ ,
CS ₂ , snubber diodes DS _{1 to} DS ₄ , snubber resistor R
And a S ₁ to RS _3. Snubber capacitor CS
_1, CS ₂ are each configured by connecting three capacitors C ₁ -C ₃ in delta. The gate pulses amplified are input by the gate driver GD to the gates of the semiconductor switch modules SM ₁ to SM _4.

Here, a specific structure of the power unit PU will be described with reference to FIGS. FIG. 1 is a configuration diagram of a main part when one power unit is viewed from the side.
FIG. 2 is a configuration diagram viewed from an arrow II-II in FIG. 3A and 3B are enlarged views showing the arrangement and electrical connection of the semiconductor switch module and the clamp diode on the heat receiving plate.

As shown in these figures, each of the semiconductor switch modules SM _{1 to} SM ₄ is configured by connecting two semiconductor switch modules arranged side by side in parallel.
The positive-side semiconductor switch modules SM ₁ and SM ₂ are vertically mounted on the surface of the first heat receiving plate 31, and the negative-side semiconductor switch modules SM ₃ and SM ₄ are mounted on the second heat receiving plate 3.
It is attached to the surface of 2 vertically. Further, the surface of each heat receiving plates 31 and 32, are mounted clamp diodes DC ₁ and DC _2. Clamp diode D
C ₁ and DC ₂ are also configured by connecting two diodes in parallel. Those semiconductor switch modules SM _{1 to} S
M ₄ and the clamp diodes DC _1, DC ₂ is, and FIG. 3 (B)
As shown in FIG.
16 are connected.

Semiconductor switch modules SM _{1 to} SM
₄ has the same configuration, and has a structure as shown in a perspective view partially broken away in FIG. That is, an insulating plate 22 such as alumina is placed on a substrate 21 formed of a material having excellent heat conductivity such as copper, and a first main electrode such as a conductive copper plate is placed on the insulating plate 22. 23, and a plurality of thermal stress relaxation plates 24 made of conductive molybdenum or the like are placed on the main electrode 23, and IG is placed on each thermal stress relaxation plate 24.
The BT element 25 is placed, and the second main electrode 26a such as a conductive copper plate is placed on the first main electrode 23 by the insulating plate 26.
b, and the entire structure is covered with an insulating case 27. A pair of main electrode terminals 28 and a gate terminal 29 are exposed on the outer surface of the insulating case 27. Although not shown, a freewheeling diode DF connected in antiparallel to the IGBT element (Q) 25 is also mounted on the first main electrode 23. Then, the first and first bolt holes 30 provided in the substrate 21 are used.
The second heat receiving plates 31 and 32 are attached in close contact with each other.

The first and second heat receiving plates 31, 32 are formed of a material having excellent heat conductivity such as aluminum. Each of the heat receiving plates 31 and 32 is fixedly attached to a power unit support frame 33 formed in a rectangular frame shape by bolts 34.

A flange 35 is provided around the power unit support frame 33. A housing 36, only a part of which is shown in FIG. 1, houses the components of the inverter. A frame-shaped mounting seat 37 is formed around an opening on the side surface of the housing 36. The flange 35 of the power unit support frame is fixed to the mounting seat 37 via a packing 39 with bolts 38, and the power unit support frame 33 is
Attached to. That is, a part of the side surface of the housing 36 is formed by the heat receiving plates 31 and 32 and the power unit support frame 33, and airtightness is secured by the packing 39.

A component support member 40 is provided at a position sandwiching the semiconductor switch modules SM _{1 to} SM ₄ with respect to the heat receiving plates 31 and 32. The component support member 40 is fixed to the power unit support frame 33 by an arm member 41. Is mounted to face the snubber capacitor CS _1, CS ₂ and the snubber diode DS ₁ to DS ₄ to the semiconductor switch modules SM ₁ to SM ₄ for this part support member 40. Thereby, the wiring of the snubber circuit can be realized with the shortest distance.

On the surface opposite to the component mounting main member 40, terminal blocks 42 to 45 made of an insulating material such as epoxy resin are provided.
The terminal blocks 42 to 45 support DC input terminals P and N, a neutral point terminal O, and an AC output terminal M. A current transformer CT and a gate driver GD (GD ₁ , GD ₂ ) are mounted on the component support member 40 side by side on the terminal blocks 42 to 45. In the space below these CT and GD, filter capacitors CF ₁ and CF ₂ are arranged. The gate drivers GD ₁ and GD ₂ correspond to the positive side and the negative side of the semiconductor switch module, respectively.

The heat receiving plates 31 and 32 are thermally attached with coolers 53 and 54 each comprising a plurality of heat pipes 51 and radiating fins 52 attached to the heat pipes 51. The heat pipe 51 is formed of a material having excellent heat conductivity and workability, such as copper, and water as a boiling refrigerant is injected into the pipe to facilitate boiling at a low temperature and to mix non-condensable gas. It is adjusted to a negative pressure so as not to.

In the case of this embodiment, the heat pipe 51 is
It is bent into a mold, and one of the straight pipe portions is embedded in the heat receiving plates 31 and 32 and thermally connected to form the evaporating portion 51a, and the heat pipe 51 is supported by the heat receiving plate. The other straight pipe portion is provided slightly inclined upward with respect to the horizontal plane, and a plurality of radiating fins 52 are attached to this portion to form a condensing portion 51b. Further, the tip of the condenser 51b is connected by a steady rest 55, which is fixed to the heat receiving plates 31, 32 or the power unit support frame 33, so that the vibration of the heat pipe 51 is the same vibration system as the power unit support frame 33.

The operation of the inverter device for a train constructed as described above will be described below, focusing on the features of the present invention.

The gate pulse for driving and controlling the train inverter device of this embodiment is generated according to the basic operation of a well-known three-level inverter in a PWM control device (not shown) (reference: an neutral point clamped PWM). Inverter (A New Neutral-Poin
t-Clamped PWM Inverter, IEEE Transactions on indus
try applications, vol.1A-17, No.5, september / october
1981)). That is, the basic operation of the three-level inverter is to turn on / off the semiconductor switch modules SM _{1 to} SM _{4 according} to the following three conduction modes,
To selectively output three levels of voltages. Here, the total DC voltage is assumed to be Ed, and the neutral point voltage is assumed to be 0 V.

SM ₁ SM ₂ SM ₃ SM ₄ Output voltage First conduction mode ON ON OFF OFF Ed / 2 Second conduction mode OFF ON ON OFF 0 Third conduction mode OFF OFF ON ON-Ed / 2 According to such a three-level inverter, the number of steps of the voltage level of the output voltage pulse is increased and the apparent switching frequency is increased as compared with a normal two-level inverter, so that harmonics are reduced. Also, since the IGBT is used as the semiconductor switch element,
The switching frequency can be increased to a range of 500 Hz to 3 kHz, and from this point as well, harmonics can be suppressed and electromagnetic noise can be reduced.

The PWM control device generates a gate pulse according to the above three conduction modes and the specified target speed and traveling mode of the train, and controls on / off of each semiconductor switch module via a gate driver, and an inverter device. Output voltage and frequency are variably controlled, and the inverter device is controlled in accordance with the running mode (powering, coasting, braking) of the train.

The semiconductor switch modules SM _{1 to} SM ₄ generate heat due to the loss during the ON operation. In this embodiment, the heat is radiated by the cooling system including the heat receiving plates 31 and 32 and the coolers 53 and 54, and is maintained at a predetermined allowable temperature or lower. That is, first, the heat of the semiconductor switch modules SM _{1 to} SM ₄ is transferred to the heat receiving plate 3 via the substrate 21.
1, 32, the temperature of the heat receiving plates 31, 32 rises.
Next, the water in the evaporating section 51a of the heat pipe 51 boils and evaporates due to the temperature rise of the heat receiving plates 31, 32, and the heat receiving plates 31, 32 are cooled by the heat of evaporation. The evaporated water in the heat pipe 51 is guided to the condensing part 51b, and exchanges heat with the running wind of the train (basically, the wind in a direction perpendicular to the plane of the paper) via the radiation fins to condense. The condensed water flows along the inner wall of the heat pipe 51 and returns to the evaporator 51a, and the above-described cooling operation is repeated.

By the way, the loss (heat generation) of the semiconductor switch modules SM _{1 to} SM ₄ forming the three-level inverter, as shown in the heat generation cycle of the semiconductor element shown in FIGS. It was found to be related to the driving modes (powering, coasting, braking). In other words, the loss of the semiconductor switch modules SM ₁ and SM ₄ has a peak during power running, the loss of the semiconductor switch modules SM ₂ and SM ₃ is a peak during braking.

[0045] In view of this, in the present embodiment shown in FIG. 1, fitted with SM ₁ and SM ₂ pairs loss peak is shifted to the same heat receiving plate 31, similarly to SM ₃ and SM ₄ The pair is mounted on the same heat receiving plate 32. This will heat input equalization of the heat receiving plates during power running and braking, than the case of providing separately cooler the semiconductor switch modules SM ₁ to SM _4, the heat load of the cooler 53 and 54 Since the amounts are averaged, the cooler can be downsized.

In addition, the freewheeling diode DF is mounted on the same substrate as the IGBT to form the semiconductor switch module SM, and the semiconductor element that generates heat and its cooling system are integrated. Contributes to

Similarly, clamp diodes DC ₁ and DC ₂
Are the same heat receiving plate 31, as the semiconductor switch module SM,
32, the heat generating semiconductor element and its cooling system can be further integrated, which contributes to downsizing of the entire apparatus. Also, since the loss of the clamp diodes DC ₁ and DC ₂ changes as shown in FIG.
The heat load of the cooler can be averaged to some extent as compared with the case where the coolers are individually provided.

On the other hand, as shown in FIG. 4, the IGBT and the freewheeling diode DF constituting the semiconductor switch module SM are mounted on the substrate 21 via the insulating plate 22 to insulate the semiconductor element from the ground inside the module. Since the configuration is assured, the heat receiving plates 31 and 32 can be set to the ground potential. Thereby, the heat receiving plates 31 and 32
In addition, since the ground insulation of the coolers 53 and 54 becomes unnecessary, the configuration of the cooling system can be simplified, which contributes to downsizing of the entire apparatus, and the heat receiving plates 31 and 32 and the coolers 53 and 54
A heat pipe using a refrigerant such as water that does not have insulating properties can be applied as a heat transfer member that thermally connects the heat pipes. Therefore, it is possible to realize a cooling system that does not use harmful CFCs without impairing the cooling capacity.

Further, since the heat receiving plates can be set to the ground potential, the heat receiving plates 31 and 32 are detachably attached to the openings formed in the vertical outer wall of the housing 36 with the semiconductor switch module SM inside. , Heat receiving plates 31, 32
Is exposed to the outside of the housing 36. As a result, the exposed surface of the heat-receiving plate also effectively acts as a heat-radiating surface, compared to the case where the entire heat-receiving plate is installed in the housing as in the conventional case. The heat dissipation capacity of the cooler can be reduced, and the size can be reduced.

The present invention is not limited to the above embodiment, but can be realized by, for example, the following modifications.

The high frequency semiconductor switch element is not limited to the IGBT, but may be a bipolar transistor or a MOS transistor.
GTO like thyristor controlled by gate
The same effect can be obtained even if a semiconductor switch element that can be driven at a higher frequency than the above is applied.

Although the heat receiving plate is divided into the heat receiving plates 31 and 32 and the coolers 53 and 54 are respectively attached to the heat receiving plates 31 and 32, the above effects are not changed even if the heat receiving plates 31 and 32 are integrated. However, in consideration of assembling after attaching a cooler to the heat receiving plate in advance, it is easier to handle the assembling if the heat receiving plate is divided into two parts.

The heat receiving plates 31 and 32 may be divided into two on the semiconductor switch module side and the cooler side, and the heat receiving plates may have a two-layer structure. According to this, manufacture and assembly are further facilitated. However, the cooling effect may be reduced due to the heat transfer resistance between the two heat receiving plates.

Several division methods shown in FIG. 8 can be applied to the division of the heat receiving plate. This figure shows a simplified three-phase inverter main circuit portion for explaining the heat receiving plate dividing methods A to D. The division method A shown in FIG. 8 corresponds to the above-described embodiment, in which the heat receiving plates correspond to the U, V, and W phases and correspond to the positive arm (SM1 and SM2) and the negative arm (SM3, SM4). This is an example of dividing into six. In the division method B, the heat receiving plate is divided into three for each of the U, V, and W phases, and the positive arm (SM1 and SM2) and the negative arm (S
M3, SM4) are attached to a common heat receiving plate.
The division method C is an example in which the heat receiving plate is divided into two corresponding to the positive arm (SM1 and SM2) and the negative arm (SM3, SM4), and the U, V, and W phases are common. Division method C
Is an example in which the heat receiving plate is made common to the three-phase positive arm (SM1 and SM2) and the negative arm (SM3, SM4). In any of the division methods, two semiconductor switch modules SM (S
Combination of M1 and SM2 or SM3, or SM4 and SM2
Or a combination of SM3) is attached to at least a common heat receiving plate.

The cooler is not limited to the one using the heat pipe of the above-described embodiment, and as shown in FIG. 9, a radiation fin 57 is integrally formed on or attached to the heat receiving plate 31 (or 32). You may. When the heat receiving plate 31 is formed of aluminum, it is preferable that the heat radiation fins 57 be formed integrally with the heat receiving plate 31 by extrusion or drawing. Although not shown, the cooling capacity can be increased by providing a blower fan so as to generate an airflow in a direction perpendicular to the paper surface.

[0056]

As described above, according to the present invention,
It has the following effects:

First, since a three-level inverter circuit is basically applied, harmonics can be reduced, and
Since a semiconductor switch element that can be driven at a higher frequency than the TO thyristor is used, the switching frequency can be increased to reduce harmonics and output current ripples, and electromagnetic noise can be further reduced.

Also, according to the powering and braking operation modes of the electric motor of the train, the loss of the pair of the first and second semiconductor switch elements forming the three-level inverter main circuit, and the third and fourth semiconductors Considering that the loss of the switch element pair is averaged, the same pair of semiconductor switch modules are mounted on the same heat receiving plate, and a cooler is mounted on the heat receiving plate. The amounts can be averaged. As a result, the cooler can be downsized, which can contribute to downsizing of the entire apparatus.

In addition, according to the semiconductor switch module formed by mounting the free wheeling diode on the same substrate as the semiconductor switch element and mounting the semiconductor switch module to the heat receiving plate, heat is generated. Since the semiconductor element and its cooling system can be integrated, it can contribute to downsizing of the entire device.

Further, if the clamp diode is mounted on the same heat receiving plate as the semiconductor switch module, the heat generating semiconductor element and its cooling system can be further integrated, thereby contributing to downsizing of the entire device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part of an electric vehicle inverter device according to an embodiment to which the present invention is applied.

FIG. 2 is a configuration diagram of the embodiment of FIG. 1 as viewed from an arrow II-II.

FIG. 3A is an enlarged view showing an arrangement of a semiconductor switch module and a clamp diode on a heat receiving plate.
FIG. 3B is a diagram illustrating an electrical connection between the semiconductor switch module and the clamp diode.

FIG. 4 is a perspective view showing a configuration of a semiconductor switch module according to an embodiment of the present invention, with a part thereof cut away;

FIG. 5 is a power system configuration diagram of a train inverter device.

FIG. 6 is a main circuit configuration diagram of one phase of a three-level inverter according to the present invention.

FIG. 7 corresponds to the operation mode of the inverter,
FIG. 4 is a diagram illustrating a loss between a semiconductor switch module and a clamp diode.

FIG. 8 is an inverter main circuit configuration diagram for explaining a method of dividing a heat receiving plate.

FIG. 9 is a view showing another embodiment of the cooler.

DESCRIPTION OF SYMBOLS 1A, B Inverter device 11 to 16 Conductor 21 Substrate 22 Insulating plate 23 Main electrode 24 Thermal stress relieving plate 25 IBGT element 27 Insulating case 28 Main electrode terminal 29 Gate terminal 31, 32 Heat receiving plate 33 Power unit support frame 35 Flange 36 Housing 37 Mounting seat 39 Packing 40 Parts support member 41 Arm member 42 to 45 Terminal block 51 Heat pipe 52 Heat radiating fin 53, 54 Cooler 55 Steady stop 57 Heat radiating fin PU _{1 to} PU ₃ Power unit SM _{1 to} SM ₄ semiconductor switch modules _{Q 1 ~Q 4 IGBT DF 1 ~DF} 4 freewheeling diode CS ₁ to CS ₂ snubber capacitor DS ₁ to DS ₄ snubber diode RS ₁ to RS ₃ snubber resistor DC _1, DC ₂ clamp diodes CF _1, CF ₂ filter capacitor CT current transformer

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takeshi Ando 1070 Ma, Katsuta-shi, Ibaraki Hitachi, Ltd. Mito Plant (72) Inventor Eiichi Toyoda 1070 Ma, Katsuta-shi, Ibaraki Hitachi, Ltd.Mito Inside the plant (72) Inventor Takayuki Matsui 1070 Ma, Katsuta-shi, Ibaraki Pref. Inside the Mito Plant, Hitachi, Ltd. (72) Inventor ▲ Toshihiko Taka ▼ Hisashi 832. Inside Engineering Co., Ltd. (72) Inventor Kiyoshi Nakamura 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Kiyoshi Nakata 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research Laboratory (58) Fields investigated (Int. Cl. ⁶ , DB name) H02M 7/42-7/98 H02M 1/00

Claims (10)

(57) [Claims] An inverter (1) comprises a main circuit of each phase comprising a pair of DC input terminals (P, P) connected to a DC power supply.
N), a neutral terminal (O) connected to a neutral point of the DC power supply, and a first terminal connected between the pair of DC input terminals.
To fourth semiconductor switch modules (SM _{1 to} SM ₄ )
And a connection point (12) between the first and second semiconductor switch modules and a connection point (14) between the third and fourth semiconductor switch modules and the neutral terminal. Between the clamp diodes (DC
₁ , DC ₂ ) and an AC output terminal (M) connected to a connection point between the second and third semiconductor switch modules. the first through fourth semiconductor switch modules - Le is through the substrate (21) an insulating member on (22) having a high frequency drivable semiconductor switch element than GTO thyristors, respectively (Q ₁ to Q ₄₎ the heat transfer And the first and fourth semiconductor switch modules (SM ₁ ,
One said second and third semiconductor switch modules of SM ₄₎ - Le (SM _2, SM ₃₎ in combination one of the classified into two pairs, at least a common heat receiving plate for each of the pairs (3
1 and 32), wherein cooling means (53, 54, 57) for thermally cooling the heat receiving plate are thermally connected to the heat receiving plate. 2. A method according to claim 1, wherein two pairs of said inverter - the classified for each phase of the motor main circuit first and second semiconductor switch modules - le of (SM _1, SM ₂₎ a pair, and the third and fourth semiconductor switch modules - consists of a pair of Le (SM _3, SM _4), the heat receiving plate, said inverter - each and the two pairs for each phase of the motor main circuit An inverter device for an electric vehicle, which is provided separately for the electric vehicle. 3. The electric vehicle according to claim 1, wherein the heat receiving plate is formed in common for the two pairs and separately for each phase of the inverter main circuit. Inverter device. 4. The semiconductor device according to claim 1, wherein said two pairs are a pair of said first and second semiconductor switch modules classified for each phase of said inverter main circuit, and said third and fourth pairs. An inverter device for an electric vehicle, comprising a fourth pair of semiconductor switch modules, wherein the heat receiving plate is formed commonly to the two pairs. 5. The semiconductor device according to claim 1, wherein the two pairs are a pair of the first and second semiconductor switch modules classified for each phase of the inverter main circuit, and the third pair. A fourth semiconductor switch module pair, wherein the heat receiving plates are formed separately for each of the two pairs and commonly for each phase of the inverter main circuit. Inverter device for an electric vehicle. 6. The electric device according to claim 1, wherein the heat receiving plate is provided common to the two pairs and common to each phase of the inverter main circuit. Inverter device for car. 7. In any of claims 1 to 6, wherein the clamp diode - electric vehicle, characterized in that the de-attached to the heat receiving plate inverter - motor unit. 8. In any one of claims 1 to 7, wherein the heat receiving plate, the inverter - the opening formed in the outer wall of the housing for sealing housing the motor components, the semiconductor switch module - le is An inverter device for an electric vehicle, wherein the inverter device is detachably attached with the attached surface inside the housing. 9. The inverter device for an electric vehicle according to claim 8 , wherein the first to fourth semiconductor switch modules attached to the heat receiving plate are arranged in the order in which they are connected in series. . 10. In any one of claims 1 to 9, wherein the cooling means, heat - part of heat pipe (51) (51
(a) is embedded in the heat receiving plate, and a radiation fin (52) is attached to an exposed portion of the heat pipe.