JP2896454B2 - Inverter device - 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 device, and more particularly to an inverter device 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 is, for example, in the case of a train provided with electric motors distributed on a plurality of axles,
Since it must be fitted in a limited space under the floor, it is demanded to make the device as small as possible. Similarly, even in the case of an electric locomotive, in order to increase the total capacity of the inverter device group mounted on one locomotive, it is desired that each inverter device be downsized.

In order to satisfy such demands, conventionally, as a semiconductor switch element of an inverter main circuit for driving an electric vehicle, Japanese Utility Model Application Laid-Open No. 2-753838 or literature: GT-O-Stromrichter Fuerbahnen (GT)
O-Stromrichter fuer Bahnen: SIEMENS, Sonderdruck a
As described in US ZEV-Glasers Annalen 113 (1989) Nr. 6/7 juni / juli pp. 259-272), a gate turn-off thyristor (GTO thyristor) is used. This is because the withstand voltage and current capacity are relatively large as compared with 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.

On the other hand, in order to reduce the harmonic components of the output waveform, as described in the above-mentioned document (GTO-Stromrichterfuer Bahnen), 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;
Between the connection point of the semiconductor switch element and the neutral terminal,
A clamp diode connected between a connection point of the third and fourth semiconductor switch elements and a neutral terminal, and an AC output terminal connected to a connection point of the second and third semiconductor switch elements. Is included.

Further, since the GTO thyristor has a large switching loss, in order to enhance the cooling efficiency, the GTO thyristor is formed in a disk shape as described in the above publications and documents, and both surfaces of the disk are used as main electrodes. A cooler having a configuration in which a conductive cooling block is pressed against each of the main electrodes and a boiling refrigerant flows through the inside of 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 GTO thyristor has a large switching loss due to a large switching loss of the 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 which cannot be increased and which has been practically used is about 500 Hz at most. 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. It is conceivable to apply the following.

However, these devices used as high-frequency semiconductor switching devices generally have a low withstand voltage level (for example, a general-purpose IGBT is 1200 V level). Are connected in series and used. 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 Are connected and used in parallel.

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. It is desired to make the device smaller as a whole.

In addition, there is a demand for miniaturization of a cooling system for a high-frequency semiconductor switch element such as an IGBT, and there is a demand for the use of an alternative cooling system of the Freon boiling cooling system from the viewpoint of preventing pollution.

Further, if the size is simply reduced, the arrangement of the components and the related wiring are complicated, so that there is a problem that maintainability such as inspection and repair deteriorates. In particular, in the case of an inverter device for an electric vehicle, since it is provided in a narrow place such as under a train floor, it is necessary to sufficiently consider maintainability.

A first object of the present invention is to provide an inverter device capable of increasing the switching frequency to reduce the ripple of the output current and reducing the size of the entire device.

A second object of the present invention, in addition to the first object, is to provide an inverter device which allows a cooler to be downsized and does not use a Freon refrigerant.

[0015] A third object of the present invention is to provide an inverter device in which easy maintenance is ensured in addition to the first and second objects.

[0016]

Means for Solving the Problems In order to achieve the above object, the present invention is characterized by comprising the following means.

In order to achieve the first object, a first feature of the inverter device of the present invention is that an element which can be driven at a higher frequency than a GTO thyristor is used for a plurality of semiconductor switch elements forming an inverter main circuit. A snubber capacitor forming a snubber circuit of a semiconductor switch element is arranged at a position sandwiching the semiconductor switch with respect to a support surface on which a semiconductor switch element to be connected is mounted.

In order to achieve the second object, a second feature of the inverter device of the present invention is that a plurality of semiconductor switch elements forming a three-phase inverter main circuit are respectively provided on a substrate having heat conductivity via an insulating member. The semiconductor switch module is mounted to form a semiconductor switch module, and the plurality of semiconductor switch modules are divided for each phase and mounted on one surface of the same heat-receiving plate having conductivity.

In this case, it is preferable that the semiconductor switch modules for one phase attached to the heat receiving plate are arranged in the order in which they are interconnected.

Further, it is preferable to use a boiling cooling type using water as a cooling medium for cooling the semiconductor switch module via the heat receiving plate.

In order to achieve the third object, a third feature of the inverter device of the present invention is that a component and a gate driver of a three-phase inverter main circuit are divided into one-phase units, and that
That is, a power module is formed by incorporating each phase into the same support frame, and the power module is detachably incorporated in a common housing.

In this case, the power module of each phase includes a plurality of serially connected semiconductor switch modules for one phase of an inverter main circuit, a snubber capacitor and a snubber diode forming a snubber circuit for each semiconductor switch module, It is preferable to include a cooler for cooling a heating element including a semiconductor switch module, and a wiring terminal for performing wiring related to components other than the components constituting the power module. Then, the semiconductor switch module is formed by mounting a semiconductor switch element on a substrate having heat conductivity via an insulating member, and is attached to one surface of the same heat receiving plate having conductivity via the substrate. It is preferable that a cooler is thermally connected to the other surface of the heat receiving plate, the cooler is positioned outside the housing, and the heat receiving plate is detachably attached to the housing. Further, the snubber capacitor and the snubber diode are arranged at a position where the semiconductor switch module is sandwiched with respect to the heat receiving plate, and at a position where the terminals of the snubber capacitor and the snubber diode are close to the main electrode terminal of the semiconductor switch module to be connected. Is preferred.

It is preferable that a snubber resistor forming a snubber circuit and a filter capacitor forming an inverter main circuit be supported by a support frame of the power module.

It is preferable that the heat receiving plate is vertically attached to the housing, and that the semiconductor switch modules for one phase attached to the heat receiving plate are vertically arranged in the order of serial connection.

Further, it is preferable that a filter capacitor connected in parallel to the DC power supply of the inverter main circuit is incorporated in each power module, and is disposed at a position sandwiching the snubber capacitor with respect to the semiconductor switch module.

[0026]

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

Basically, in the present invention, the use of a semiconductor switch element (hereinafter abbreviated as a high-frequency semiconductor switch element) which can be driven at a higher frequency than the GTO thyristor reduces the ripple of the output current and reduces electromagnetic noise. Be improved. The purpose of reducing the size of the inverter device by avoiding the increase in size of the device caused by using such a high-frequency semiconductor switch element is achieved as follows.

First, bipolar transistors, IGBTs, thyristors controlled by MOS gates, and the like are known as high-frequency semiconductor switch elements. These high-frequency semiconductor switch elements have a smaller switching loss than the GTO thyristor, and thus can operate at a high frequency. For example, in the case of an IGBT, the switching frequency can be selected in the range of 500 Hz to 3 kHz. Also, IG
The switching loss of the BT is a fraction of the GTO at 500 Hz, and several tenths of the GTO at 3 kHz.

Further, the high frequency semiconductor switch element is a GT
Since the power required for the gate drive is smaller than that of the O-thyristor, the gate driver can be downsized, which contributes to downsizing of the entire device.

The high-frequency semiconductor switch element is a GT switch.
Since the safe operation area at the time of turn-off is wider than that of the O-thyristor (for example, because the allowable voltage rise rate is high), the capacity of the snubber capacitor can be reduced, and the snubber loss consumed by the snubber resistor is also reduced. For example, IGB
In the case of T, the capacitance of the snubber capacitor can be reduced to 1/10 or less as compared with the GTO thyristor.

However, if the capacitance of the snubber capacitor is simply reduced, the high-frequency semiconductor switch element has a problem that a large spike voltage and overshoot voltage are likely to be applied to the element at the time of turn-off because the current cutoff speed is faster than that of the GTO thyristor. . In particular, in the case of an IGBT, a problem arises because the current cutoff speed is at least one order of magnitude faster than that of a GTO thyristor.

This spike voltage is generated mainly by the electromagnetic energy stored in the wiring inductance of the snubber circuit of the inverter main circuit. Therefore, it is important to reduce the wiring inductance of the snubber circuit in order to keep the spike voltage within the safe operation area of the semiconductor switch element.

Therefore, according to the first feature of the present invention, since the snubber capacitor is arranged at a position sandwiching the semiconductor switch with respect to the support surface on which the semiconductor switch element to be connected is mounted, the snubber capacitors are connected. Wiring can be made as short as possible. As a result, the inductance of the wiring can be reduced and the spike voltage can be reduced, so that the capacity of the snubber capacitor can be reduced, which can contribute to downsizing of the device.

In this case, the semiconductor switch element is mounted on a substrate having heat conductivity, the main electrode terminal of the semiconductor switch element is provided on the opposite side of the substrate, and the snubber capacitor is connected to the semiconductor switch element to be connected to the terminal of the snubber capacitor. It is preferable to arrange at a position close to the main electrode terminal. Thereby, the wiring inductance of the snubber circuit can be minimized.

In addition, since the semiconductor switch element and the snubber capacitor are arranged in a three-dimensional structure, that is, they are arranged not in the same plane but in a two-layered hierarchical structure, so that the overall size of the device can be reduced. Contribute.

On the other hand, one phase of the inverter main circuit includes upper and lower arm semiconductor switch elements connected to a DC power supply. Since these semiconductor switch elements do not turn on at the same time, the heat generation cycles of the elements do not overlap.

Therefore, as a second feature of the present invention, the semiconductor switch module is divided for each phase and mounted on one surface of the same heat receiving plate, and a cooler is thermally connected to the other surface of the heat receiving plate. For example, the heat load of the cooler can be averaged. As a result, the cooler can be downsized, which can contribute to downsizing of the entire apparatus.

Further, when the semiconductor switch elements for one phase are mounted on the same heat-receiving plate having conductivity, insulation between the elements must be provided. In addition, when the heat-receiving plate is set to the ground potential, it must be insulated from the heat-receiving plate. No. In this regard, each semiconductor switch element is mounted on a substrate having heat conductivity via an insulating member, thereby ensuring insulation between the elements and between the elements.

As described above, since the semiconductor switch elements are insulated from each other, even if a cooling medium of a boiling refrigerant type is used, the insulating property of the refrigerant is not required. Can be used.

In particular, it is preferable that the semiconductor switch modules for one phase attached to the heat receiving plate are arranged in the order in which they are mutually connected in series. According to this, since the wiring of the main circuit can be shortened and the wiring inductance can be reduced, the overshoot voltage at the time of turning off the semiconductor switch element can be reduced, and as a result, the snubber capacitor can be downsized. That is, the overshoot voltage generated when the semiconductor switch element is turned off mainly depends on the electromagnetic energy stored in the wiring inductance of the inverter main circuit as viewed from the semiconductor switch element.

As described above, for example, when the semiconductor switch elements for one phase are mounted on the same heat receiving plate and the snubber capacitors are arranged in a hierarchical manner with respect to the semiconductor switch elements, maintenance such as inspection and repair can be performed. Worse.

In this regard, according to the third feature of the present invention, 1
A power module is created for each inverter main circuit for each phase,
Since the power module is detachably incorporated in the common casing, the necessary power module is removed from the casing during maintenance, so that each component can be easily accessed, and maintainability is improved. In particular, according to the one incorporating the gate driver, the operation test of the semiconductor switch element can be easily performed. In other words, when an operation test is performed using a test gate driver, various test gate drivers must be prepared in accordance with the gate characteristics and capacitance of the semiconductor switch element. There is no need to prepare such various test gate drivers. .

Further, since the module is formed in units of one phase, even when a failure occurs in some parts, it can be quickly restored by replacing only the failed module. In addition, spare parts may be prepared not for each inverter device but for each power module. The power module divided into one-phase units is relatively lightweight and can be carried by a simple carrier.

Further, the spike voltage and the overshoot voltage when the semiconductor switch element is turned off are also affected by the wiring inductance connecting the filter capacitor connected in parallel to the DC power supply of the inverter main circuit and the semiconductor switch element. . Therefore, according to the filter capacitor, the filter capacitor is dispersed for each phase and incorporated in each power module, and the filter capacitor is disposed at a position sandwiching the snubber capacitor with respect to the semiconductor switch module.
The spike voltage can be further reduced, and the snubber capacitor can be reduced in capacity. In addition, by adopting such an arrangement, the utilization rate of the space having the three-dimensional arrangement can be improved, and the entire apparatus can be downsized. As a result, the size can be reduced to a size that can be installed in a limited space such as an electric car.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. A train inverter device according to one 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-I of FIG.
FIG. FIG. 3 is an overall system configuration diagram of the train inverter device of the present embodiment, and FIG. 4 is a configuration diagram of an inverter main circuit for one phase. FIG. 5 is a rear view of the entire external view of the train inverter device 1 shown in FIG. FIG. 6 is a sectional view taken along the arrow VI-VI in FIG. FIG. 7 is a diagram showing a state in which the train inverter device of the present embodiment is fitted under the floor of a train. FIG. 8 is a perspective view, partially cut away, of the configuration of the semiconductor switch module according to the present embodiment. FIG. 9 is an enlarged view showing the arrangement of the semiconductor switch module and the clamp diode on the heat receiving plate and their electrical connection. FIG. 10 is a diagram showing an overlapping relationship of the hierarchical arrangement of the semiconductor switch module and the snubber capacitor.

First, with reference to FIGS. 3 to 7, the overall configuration of the train inverter device of the present embodiment and the inverter main circuit will be described. As shown in FIG. 3, the train drive device to which the train inverter device of the present embodiment is applied is configured to include four induction motors M ₁ , M ₂ , M ₃ , and M ₄ . Two inverter devices 1A and 1B having the same configuration are provided for these four induction motors, the induction motors M ₁ and M ₂ are driven by the inverter device 1A, and the induction motors M ₃ and M ₄ are driven by the inverter device 1B. To drive. Each inverter 1A, B is an inverter main circuit of each of the three phases, including a power module PU ₁ to PU ₃ obtained by dividing for each phase. One DC input terminal (P) of each of the power modules 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 (P). N) is grounded.

As a main circuit of each of the power modules PU _{1 to} PU ₃ , a so-called three-level inverter circuit is applied as shown in FIG. FIG. 4 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 is composed of a snubber capacitor CS ₁ ,
CS ₂ and the snubber diode DS ₁ ~DS ₄ and the snubber resistor R
And a S ₁ to RS ₃ Prefecture. Snubber capacitor C
S _1, CS ₂ 3 respective ones of the capacitors C ₁₁ ~C _13, C
It is constructed by connecting ₂₁ -C ₂₃ in delta. The snubber capacitors CS ₁ and CS ₂ can be equivalently configured by connecting three capacitors in a star configuration. The gate pulses amplified are input by the gate driver GD to the gates of the semiconductor switch modules SM ₁ to SM _4.

As shown in FIG. 5, the entirety of the train inverter device 1 of this embodiment is provided with a control unit C
U-A, B and adjunct AU-A, mainly B, inverter 1A, and the power module PU ₁ to PU ₃ and B is constructed by arranging on both sides symmetrically. As shown in the cross-sectional view of the train inverter device 1 shown in FIG.
A portion 4 is provided so as to protrude outside the front side of the housing 6. The train inverter device 1 configured as described above.
As shown in FIG. 7, a plurality of hanging metal fittings 7 provided on the upper part of the housing 6 are aligned with the longitudinal direction of the train.
And is attached by suspending it under the floor at the center of the train car 8 via the. Further, the coolers 53 and 54 are attached with the side facing the outside of the vehicle 8.

Next, a specific structure of the power module PU will be described with reference to FIGS. FIG. 1 is a configuration diagram of a main part when one power module is viewed from the side.
FIG. 2 is a configuration diagram viewed from an arrow II-II in FIG.

As shown in these figures, each of the semiconductor switch modules SM _{1 to} SM ₄ has two semiconductor switch modules connected in parallel, and these semiconductor switch modules are arranged side by side. The semiconductor switch modules SM ₁ and SM ₂ of the positive arm are mounted vertically on the surface of the first heat receiving plate 31, and the semiconductor switch modules SM ₃ and SM ₄ of the negative arm are mounted on the surface of the second heat receiving plate 32. Mounted vertically. Also,
A clamp diode DC is provided on the surface of each heat receiving plate 31, 32.
₁ and DC ₂ are installed. Clamp diode D
C ₁ and DC ₂ are also configured by connecting two diodes in parallel.

Semiconductor switch modules SM _{1 to} SM
Reference numeral ₄ denotes the same configuration, which is formed in a structure as shown in a perspective view partially broken away in FIG. That is, an insulating plate 62 such as alumina is placed on a substrate 61 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 62. Put 63,
A plurality of conductive thermal stress relaxation plates 64 such as molybdenum are placed on the main electrode 63, the IGBT elements 65 are placed on each thermal stress relaxation plate 64, and the first main electrode 63 A second main electrode 66 made of a conductive copper plate or the like is placed thereon, and the entire structure is covered with an insulating case 67. A pair of main electrode terminals 6 is provided on the outer surface of the insulating case 67.
8 and the gate terminal 69 are exposed. Although not shown, the free wheeling diode DF connected in anti-parallel to the IGBT element (Q) 65 is also a first wheeling diode.
Is mounted on the main electrode 63. The first and second heat receiving plates 3 are provided by bolt holes 70 provided in the substrate 61.
1, 32 are attached in close contact. As shown in FIG. 9, semiconductor switch modules SM _{1 to} SM ₄ and clamp diodes DC ₁ and DC ₂ are arranged on heat receiving plates 31 and 32, and conductors 11 to 16 are arranged according to the circuit configuration of FIG. 4. It is connected.

The first and second heat receiving plates 31 and 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 module support frame 33 formed in a rectangular frame shape by bolts 34.

A flange 35 is provided around the power module support frame 33. A frame-shaped mounting seat 37 is formed around an opening formed on the side surface of the housing 6. Then, the flange 35 of the power module support frame is fixed to the mounting seat 37 via a packing 39 with bolts 38, and the power module support frame 33 is mounted on the housing 6. That is, a part of the side surface of the housing 6 is formed by the heat receiving plates 31 and 32 and the power module 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 module 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.
As shown in FIG. 10, the overlapping relationship of the arrangement of these components is determined so that the terminals to be connected are brought close to each other. Thereby, the wiring of the snubber circuit can be mounted in the shortest distance.

At a position opposite to the component support member 40,
Terminal blocks 42 to 45 made of an insulating material such as epoxy resin are attached, and the DC input terminals P and N, the neutral point terminal O, and the AC output terminal M are supported on these terminal blocks 42 to 45. A current transformer CT and a gate driver GD (GD ₁ , GD ₂ ) are provided beside the terminal blocks 42 to 45 by the component supporting members 40.
Attached to. 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 sealed inside the pipe to facilitate boiling at a low temperature or use a non-condensable gas. Is adjusted to a negative pressure in order to prevent mixing.

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. In addition, 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 module support frame 33, so that the swing of the heat pipe 51 is in the same vibration system as the main body of the inverter device.

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

The gate pulse for driving and controlling the train inverter device of the present embodiment is generated by a PWM control device (not shown) of the control unit CU in accordance with the basic operation of a well-known three-level inverter (reference: New Neutral point clamped PWM inverter (AN
ew Neutral-Point-Clamped PWM Inverter, IEEE Tra
nsactions on industry applications, vol.1A-17, No.
5, september / october1981)). That is, the basic operation of the three-level inverter is the semiconductor switch module SM
The ₁ to SM Q ₁ to Q ₄ of ₄ are turned on and off in accordance with the conduction mode the following three, the 3-level voltage selectively outputs to the AC output terminal M. Here, the total DC voltage is indicated as Ed, and the neutral point voltage is indicated as Ed / 2v.

Q ₁ Q ₂ Q ₃ Q ₄ Output voltage first conduction mode ON ON OFF OFF Ed Second conduction mode OFF ON ON OFF Ed / 2 Third conduction mode OFF OFF ON ON 0 Such three levels According to the inverter, the number of steps of the voltage level of the output voltage pulse is increased as shown in FIG. 11 and the apparent switching frequency is increased as compared with the ordinary two-level inverter, so that the harmonics are reduced. You. Further, since the IGBT is used as the semiconductor switch element, the switching frequency is set to 500 Hz to 500 Hz.
The range can be as high as 3 kHz, and from this point as well, harmonics can be suppressed and electromagnetic noise can be reduced.

Next, snubber capacitors CS ₁ and CS ₂ ,
The snubber diode DS ₁ to DS _4, in proximity to the semiconductor switch modules SM ₁ to SM ₄ each connection object,
In addition, a description will be given of the fact that the wiring inductance of the snubber circuit is reduced and the spike voltage is reduced by disposing the snubber circuit at the opposed position, so that the snubber capacitor can be downsized and the entire device can be downsized.

FIG. 12 shows the semiconductor switch module SM ₁ of FIG. 4 and a part of the snubber circuit. It is assumed that each wiring inductance L _1, L ₂ are present in the semiconductor switch modules SM ₁ and snubber circuit. There IBGT Q ₁ is turned on, when to turn off the IGBT Q ₁ when the current I is flowing in the wiring inductance L ₁ and the IGBT Q _1, the current from the wiring inductance L _2, the snubber diode DS _1, snubber capacitor C ₁₁ Turning to snubber circuit formed by the charge in the snubber capacitor C ₁₁ is accumulated, the current is cut off.

[0063] and the voltage V of the IGBT Q ₁ at this time, IG
And current I ₁ of the BT Q _1, shows a waveform of the current I ₂ of the snubber circuit in FIG. 13. The voltage indicated by V _DP in the figure is called a spike voltage. If this voltage is not lower than a certain value determined from a safe operation area of a semiconductor switch element such as an IGBT, I
GBT is damaged.

[0064] mainly L ₂ of the spike voltage V _DP is the wiring inductance L _1, L _2, determined by the rate of change of current at turn-off of the semiconductor switching element such as IGBT. I
Since a high-frequency semiconductor switch element such as a GBT is turned off at a high speed, the current change rate is large. Therefore, in order to keep the spike voltage V _DP low, the wiring inductance L
_1, it is important to reduce the L _2.

Therefore, in this embodiment, as shown in FIGS. 1, 2 and 10, the snubber capacitors CS ₁ and CS ₂ and the snubber diodes DS _{1 to} DS ₄ are brought close to the semiconductor switch modules SM _{1 to} SM _4. The wiring inductances L ₁ and L ₂ are made as small as possible by realizing the connection wiring between these components at the shortest distance. As a result, small-capacity snubber capacitors CS ₁ , C
Even if S ₂ is used, the spike voltage V _DP can be kept low, which contributes to downsizing of the device.

Further, in this embodiment, since the three capacitors constituting the snubber capacitors CS ₁ and CS ₂ are formed integrally, the wiring inductance can be further reduced and the capacitors can be downsized.

Next, the features of the cooling system for cooling the semiconductor switch module of this embodiment will be described.

The PWM control device generates a gate pulse according to the above three conduction modes and the specified target speed and running mode of the train, performs PWM control on each semiconductor switch module via a gate driver, and outputs the output voltage and the output voltage of the inverter device. In addition to variably controlling the frequency, 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.

In view of this, as shown in FIG.
In this embodiment, the loss peaks of SM ₁ and SM ₂ are shifted.
Are mounted on the same heat receiving plate 31, and SM ₃ and SM ₄
Are mounted on the same heat receiving plate 32. This allows
It is heat input equalization of the heat receiving plate at the time of braking and power running, than the case of providing separately cooler the semiconductor switch modules SM ₁ to SM _4, the heat load of the cooler 53, 54 Mean Therefore, the size of the cooler can be reduced.

Further, as shown in FIG. 8, a freewheeling diode DF is mounted on the same substrate as the IGBT to form a semiconductor switch module SM, and a semiconductor element which generates heat and its cooling system are integrated. This contributes to downsizing of the entire device.

In this case, the snubber diode DS can also be formed integrally with the semiconductor switch module SM. According to this, the above-described wiring inductance can be further reduced, the cooling system can be further integrated, and the size of the device can be reduced. Can contribute.

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. 8, the IGBT and the freewheeling diode DF constituting the semiconductor switch module SM are connected to the substrate 61 via the insulating plate 62.
The heat receiving plates 31 and 32 can be set to the ground potential because the semiconductor device is placed on the heat sink and the insulation of the semiconductor element to the ground is secured inside the module. Thereby, the heat receiving plate 31,
32 and the coolers 53 and 54 are not required, so that the configuration of the cooling system can be simplified, which contributes to the downsizing of the entire apparatus, and the heat receiving plates 31 and 32 and the cooler 5.
As a heat transfer member for thermally connecting the heat transfer members 3 and 54, a heat pipe using a refrigerant such as water having no insulating property can be applied. 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 plate can be set to the ground potential, the heat receiving plates 31 and 32 can be directly attached to the housing 6. Therefore, in the present embodiment, as shown in FIGS. 1 and 2, the heat receiving plates 31 and 32 are detachably attached to the openings formed in the vertical outer wall of the housing 6 with the semiconductor switch module SM inside. Therefore, the heat receiving plates 31 and 32
Is exposed outside the housing 6. As a result, compared to the conventional case where the entire heat receiving plate is installed in the housing,
Since the exposed surface of the heat receiving plate also effectively acts as a heat radiating surface, the temperature rise inside the housing can be suppressed by the amount of the heat radiated, and the heat radiating capacity of the cooler can be reduced and the size can be reduced.

In the above embodiment, an example is shown in which an IGBT is applied as a semiconductor switch element of an inverter main circuit. However, the present invention is not limited to this.
G, such as a thyristor controlled by an OS gate
The same effect can be obtained by applying a semiconductor switch element that can be driven at a higher frequency than TO.

In the above embodiment, the heat receiving plate is divided into the heat receiving plates 31 and 32, and the coolers 53 and 54 are attached to the respective heat receiving plates 31 and 32. The effect of does not change. 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.

Further, a two-layer structure in which the heat receiving plates 31 and 32 are divided and joined to the semiconductor switch module side and the cooler side may be used. According to this, manufacture and assembly are further facilitated. However, the cooling effect may be reduced due to the heat transfer resistance of the joint surface between the two layers of the heat receiving plate.

In the above embodiment, a combination of a heat pipe and a radiating fin is shown as a cooler. However, the present invention is not limited to this, and the radiating fin is directly thermally bonded to the outer surfaces of the heat receiving plates 31 and 32. A configuration or a configuration in which a radiation fin is integrally formed with a heat receiving plate can be adopted.

As described above, when a semiconductor switch element for one phase is mounted on the same heat receiving plate and a snubber capacitor and a snubber diode are arranged in a layered manner so as to face the semiconductor switch element, inspection, repair, etc. However, according to the present embodiment, since a power module is provided for each one-phase inverter main circuit, maintainability such as inspection and repair can be improved.

That is, since the inverter main circuit is formed into a power module for each phase and is removably incorporated in a common housing, a necessary power module is detached from the housing at the time of maintenance so that each component can be easily attached to each component. Access and maintainability are improved.

In particular, since the gate driver GD is incorporated, an operation test and the like of the semiconductor switch element can be easily performed. That is, when an operation test is performed using a test gate driver, various test gate drivers must be prepared in accordance with the gate characteristics and capacitance of the semiconductor switch element, which is complicated. On the other hand, in the present embodiment, since a predetermined gate driver GD suitable for the semiconductor switch element can be used, a simple and proper operation test can be performed.

Further, since a unit is formed in units of one phase, even if a failure occurs in some parts, it can be quickly repaired by replacing only the failed power module. Moreover, spare parts are not per inverter unit,
It may be prepared for each power module. The power module divided into one-phase units is relatively lightweight,
It can be carried with a simple carrier.

The above-described spike voltage and overshoot voltage when the semiconductor switch element is turned off are affected by the wiring inductance connecting the filter capacitor CF connected in parallel to the DC power supply of the inverter main circuit and the semiconductor switch element. receive. In this embodiment,
As shown in FIG. 1, the filter capacitor CF is dispersed for each phase and incorporated as a capacitor unit.
Snubber capacitor C for semiconductor switch module
It is arranged at a position sandwiching S. Therefore, the spike voltage can be further reduced, and the capacitance of the snubber capacitor CS can be reduced. In addition, by adopting such an arrangement, the utilization rate of the space having the three-dimensional arrangement can be improved, and the entire apparatus can be downsized. As a result, the size can be reduced to a size that can be installed in a limited space such as an electric car.

Note that the filter capacitor CF can be attached to the power module support frame 33 to be integrated with the power module PU.

[0087]

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

The use of the high-frequency semiconductor switch increases the spike voltage. However, since the snubber capacitor and the snubber diode are arranged at a position sandwiching the semiconductor switch with respect to the supporting surface on which the semiconductor switch element to be connected is mounted. The wiring connecting them can be made as short as possible. As a result, the inductance of the wiring decreases,
Since the spike voltage is reduced, the capacity of the snubber capacitor can be reduced, which can contribute to downsizing of the device. further,
The components including the semiconductor switch element and the snubber capacitor are arranged in a three-dimensional hierarchical structure, which contributes to downsizing of the entire device.

The high-frequency semiconductor switch element is a GT
Since the power required for the gate drive is smaller than that of the O-thyristor, the gate driver can be downsized, which contributes to downsizing of the entire device.

Further, the semiconductor switch module is divided for each phase and mounted on one surface of the same heat receiving plate, and a cooler is thermally connected to the other surface of the heat receiving plate. The heat load can be averaged, and as a result, the cooler can be downsized, and the entire device can be downsized.

Further, according to the one in which 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, which contributes to the miniaturization of the entire device.

Further, since each semiconductor switch element is configured to be insulated from the heat receiving plate, the heat receiving plate can be set to a large ground potential, and the insulating property of the refrigerant in the cooler does not matter. It is possible to use a refrigerant.

A power module is provided for each inverter main circuit for one phase, and the power module is detachably incorporated in a common housing. Therefore, during maintenance, the necessary power modules can be easily removed from the housing so that each power module can be easily removed. Access to parts improves maintainability.

In particular, according to the one incorporating the gate driver, the operation test of the semiconductor switch element can be easily performed.

Further, since the module is formed in units of one phase, even when a failure occurs in some parts, it can be quickly repaired by replacing only the failed module. In addition, spare parts may be prepared not for each inverter device but for each power module.

Further, if the filter capacitors are dispersed for each phase and incorporated in each power module and arranged at a position sandwiching the snubber capacitor with respect to the semiconductor switch module, the spike voltage when the semiconductor switch element is turned off can be further reduced. The size of the snubber capacitor can be reduced. In addition, by adopting such an arrangement, the space utilization rate of the three-dimensional arrangement can be improved, and the depth or width of the apparatus can be reduced. As a result, the size can be reduced to a size that can be installed in a limited space such as an electric car.

[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. 3 is a power system configuration diagram of a train inverter device.

FIG. 4 is a main circuit configuration diagram of one phase of a three-level inverter according to the present invention.

5 is an overall external view of an inverter device for a train incorporating the inverter device shown in FIG. 3;

6 is a view as seen from an arrow VI-VI in FIG. 5;

7 is a diagram showing a state in which the train inverter device of FIG. 5 is fitted under a floor of a train.

FIG. 8 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. 9 is an enlarged view showing the arrangement and connection relationship between the semiconductor switch module and the clamp diode on the heat receiving plate.

FIG. 10 is a diagram showing an overlapping relationship between the arrangement of a snubber capacitor and a snubber diode with respect to a semiconductor switch module.

11 is a view for explaining the relationship between the ON-OFF operation and the output voltage of the IGBT Q ₁ to Q ₄ in FIG.

FIG. 12 is a main part circuit diagram for explaining a spike voltage generated when a semiconductor switch element is turned off.

FIG. 13 is a voltage and current waveform diagram of each part for explaining a spike voltage generated when the semiconductor switch element is turned off.

FIG. 14 is a diagram showing a loss of a semiconductor switch module and a clamp diode corresponding to an operation mode of an inverter.

[Explanation of symbols]

1A, B Inverter device 6 Housing 11 to 23 Conductor 31, 32 Heat receiving plate 33 Power module support frame 35 Flange 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 bracing 61 substrate 62 insulating plate 63 main electrode 64 thermal stress relieving plate 65 IBGT element 67 insulating case 68 main electrode terminals 69 gate terminals PU ₁ to PU ₃ power module 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

Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 25/07 H01L 25/04 C 25/18 (72) Inventor Takeshi Ando 1070 Ige, Katsuta-shi, Ibaraki Pref. 72) Inventor Eiichi Toyoda 1070 Ma, Katsuta-shi, Ibaraki Pref., Mito Plant, Hitachi, Ltd. (72) Inventor Takayuki Matsui 1070 Mo, Ichi, Katsuta-shi, Ibaraki Pref., Mito Plant, Hitachi, Ltd. Takashi Hisashi Toshihiko 832-2 Horiguchi, Katsuta-shi, Ibaraki Prefecture Hitachi Systems Plaza Katsuta Hitachi Mito Engineering Co., Ltd. (72) Inventor Kiyoshi Nakamura 1-1-1, Omikamachi, Hitachi City, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research, Ltd. In-house (72) Inventor Kiyoshi Nakata 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd.Hitachi Research Laboratory (72) Inventor Yoshio Tsutsui 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Hitachi Research Laboratory (56) Reference 2-154457 (JP, A) JP2-20346 (JP, U) JP2, 26377 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02M 7/42 -7/98

Claims (7)

(57) [Claims] A plurality of semiconductor switching elements and a filter core;
Comprising an inverter main circuit, which is formed to include a capacitor, and a snubber circuit connected to each of the semiconductor switching elements
In an inverter device using an element that can be driven at a higher frequency than a GTO thyristor for each of the semiconductor switch elements, a snubber capacitor forming each of the snubber circuits is connected to a support surface on which a semiconductor switch element to be connected is mounted. And the filter capacitor is disposed at a position sandwiching the semiconductor switch element.
An inverter device disposed at a position sandwiching the snubber capacitor with respect to a slave . 2. The semiconductor switch according to claim 1, wherein
The device consists of a bipolar transistor and a gate that can be driven at high frequency.
Controlled by a gate isolation bipolar transistor and MOS gate
An inverter device formed using any one of the thyristors controlled . 3. The semiconductor switch according to claim 1, wherein
For the element, use an element that can be driven at a high frequency of 500 Hz or more.
Inverter apparatus characterized by comprising Te. 4. An inverter main circuit including a plurality of semiconductor switch elements and a filter capacitor, and a snubber circuit connected to each of the semiconductor switch elements, wherein each of the semiconductor switch elements is provided by a GTO thyristor. In an electric vehicle inverter device using an element that can be driven at a high frequency, a snubber capacitor forming each of the snubber circuits is placed at a position sandwiching the semiconductor switch element with respect to a support surface on which a semiconductor switch element to be connected is mounted. An inverter device for an electric vehicle, wherein the filter capacitor is disposed at a position sandwiching the snubber capacitor with respect to the semiconductor switch element. 5. The inverter main circuit according to claim 4, wherein
A plurality of semiconductor switch elements that form a path
The semiconductor chip is placed on a substrate having heat through an insulating member.
A plurality of semiconductor switch modules.
Joule is divided for each phase and has the same heat conductivity
An electric vehicle interior mounted on one surface of a heat receiving plate.
Barta equipment. 6. The heat receiving plate according to claim 5, wherein
The semiconductor switch module for one phase
Characterized by being arranged in the order in which they are connected to each other
Inverter for electric vehicles. 7. A power module is formed by dividing the components of the three-phase inverter for each phase and incorporating them into one support frame to form a power module, which is mounted under the floor of a train car along the longitudinal direction of the vehicle. A plurality of semiconductor switches in which the power modules for the three phases are arranged side by side along the longitudinal direction of the housing and the components constituting the power modules for each phase are connected in series for one phase of an inverter main circuit. Module, a snubber capacitor and a snubber diode forming a snubber circuit for each of the semiconductor switch modules, a current transformer for detecting an output current, a gate driver for turning on and off the semiconductor switch module, and the semiconductor switch module A cooler that cools the heat generating element including A wiring terminal for performing continuous wiring, wherein each of the semiconductor switch modules includes a semiconductor switch element mounted on a substrate having heat conductivity via an insulating member, and a main electrode terminal disposed on the opposite side of the substrate. is formed, the snubber diode is formed by placing a diode element through the substrate to the insulating member having a heat conductivity, has a heat conductivity the each semiconductor switch modules and said snubber diode, respectively through the substrate Attach to one surface of the heat receiving plate, attach the heat receiving plate to the support frame, thermally connect the cooler to the other surface of the heat receiving plate, and sandwich the semiconductor switch module parallel to the heat receiving plate Providing a support member at a position, mounting the snubber capacitor on the semiconductor switch element side of the support member, and connecting the filter capacitor to the semiconductor A position where the snubber capacitor is sandwiched with respect to the switch module, and a terminal of the snubber capacitor is disposed at a position close to the main electrode terminal of the semiconductor switch module to be connected; A transformer and the gate driver are mounted on the support frame, and the power module is attached to and detached from an opening formed on a vehicle side surface of the housing by positioning the cooler outside through the support frame. An inverter device for an electric vehicle, wherein the inverter device is mounted as possible.