JP2010213471A - Power converter - Google Patents

Abstract

An object of the present invention is to provide a power converter capable of preventing an increase in power loss even when resonance occurs in a capacitor when a capacitor is used more than a power module.
In a power converter, 24 capacitors Cap are arranged along a common current path 10 at equal intervals. The power module PM1 is disposed between the capacitors Cap1 and 24, the capacitors Cap12 and 13 that are paired with the power module PM1 are used as a first capacitor group, and the power module PM3 is disposed between the other capacitors Cap16 and 17 and paired therewith. Capacitors Cap 4 and 5 that become the second capacitor group are arranged so that the first capacitor group and the second capacitor group are not arranged at the same position on the common current path 10.
[Selection] Figure 1

Description

  The present invention relates to a power conversion device used for an AC motor mounted on a hybrid vehicle, an electric vehicle, or the like.

  Conventionally, a power converter as described in Patent Document 1 is used for an AC motor mounted on a hybrid vehicle, an electric vehicle, or the like. This power conversion device includes a circular electrode (annular current path), a plurality of power modules, and a capacitor.

  The center of the electrode is connected to a DC power source via an input cable. The capacitor and the power module are arranged radially around the input cable on the upper and lower sides of the electrode, and are connected via the electrode. Thereby, a power converter device converts the direct current supplied from direct-current power supply into alternating current with a power module, and outputs it to an alternating current motor. At this time, the capacitor reduces ripple current and surge voltage.

  In addition, when a ceramic capacitor is used and the capacitor and the power module are connected with low impedance, resonance (resonant current) is generated in each capacitor during driving. It is known that this resonance occurs greatly for a capacitor close to the power module and a capacitor far from the capacitor. For this reason, a current larger than that of the other capacitors flows through both capacitors, and power loss increases.

  Therefore, in the conventional power converter, the number of capacitors used is set to be the same as the number of power modules used, and each capacitor is disposed near (lower side) each power module. By doing so, the magnitude of resonance generated in each capacitor becomes uniform. Therefore, the current flowing through each capacitor becomes uniform, so that power loss can be reduced.

JP-A-7-245968

  However, in conventional power converters, if more capacitors are used than power modules in order to further reduce ripple current and surge voltage, or to secure a certain amount of capacitor capacitance, the resonance generated in each capacitor. Since the sizes are not uniform, there is a problem that power loss increases.

  The present invention has been made in view of such conventional problems, and there is provided a power conversion device capable of preventing an increase in power loss even when resonance occurs in a capacitor when the capacitor is used more than a power module. The purpose is to provide.

  In order to solve the above problems, in the power conversion device of the present invention, a capacitor is disposed along a common current path, a power module is disposed between the capacitors, and a capacitor group paired with the power module is shared with the capacitor. The other power modules on the current path and a pair of capacitor groups on the common current path are arranged at different positions on the common current path.

  Therefore, in the power conversion device of the present invention, even when resonance occurs in the capacitor when the capacitor is used more than the power module, the resonance between the capacitor that resonates in one power module and the capacitor that resonates in the other power module. Since interference can be suppressed, an increase in power loss can be prevented.

It is a schematic diagram of the power converter device which shows 1st Embodiment of this invention. It is a schematic diagram at the time of the drive of the power converter device which shows the embodiment. It is a schematic diagram of the power converter device which shows 2nd Embodiment of this invention. It is a schematic diagram at the time of the drive of the power converter device which shows the embodiment. It is a schematic diagram of the power converter device which shows the 3rd Embodiment of this invention. It is a schematic diagram of the power converter device which shows 4th Embodiment of this invention. It is a schematic diagram of the power converter device which shows the 5th Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First embodiment:
FIG. 1 is a schematic diagram of a power conversion device 1 showing a first embodiment of the present invention. The power converter 1 is used for a three-phase AC motor (not shown) mounted on a hybrid vehicle, an electric vehicle, or the like. Specifically, the power conversion device 1 converts a direct current into a three-phase (U-phase, V-phase, W-phase) alternating current and outputs it to a three-phase alternating current motor. The power conversion device 1 includes an annular common current path 10, six power modules PM, 24 capacitors Cap, and three drive circuits PMD. Since each component is publicly known, it will be briefly described below.

  The common current path 10 passes a direct current supplied from a direct current power source. The member forming the common current path 10 is not particularly limited as long as it has an annular common current path.

  The six power modules PM are connected to the common current path 10. These six power modules PM convert a direct current into an alternating current and output it to an alternating current motor.

  In addition, the six power modules PM are configured with two power modules PM as one set. The power modules PM1 and PM2 convert DC current into U-phase AC current and output it to the exchange motor. The power modules PM3 and 4 convert DC current into V-phase AC current and output it to an AC motor. The power modules PM5 and 6 convert DC current into W-phase AC current and output it to an AC motor.

  The 24 capacitors Cap are connected to the six power modules PM via the common current path 10. These 24 capacitors Cap reduce the ripple current and surge voltage as is well known. In the present embodiment, a ceramic capacitor is used as the capacitor Cap. This ceramic capacitor has a relatively low impedance among various types of capacitors. Accordingly, each capacitor Cap is connected to each power module PM with a low impedance.

  The three drive circuits PMD each drive each power module PM. Each drive circuit PMD will be described. First, the drive circuit PMD1 drives the power modules PM1 and PM2. The drive circuit PMD2 drives the power modules PM3 and PM4. The drive circuit PMD3 drives the power modules PM5 and PM6.

  Next, the arrangement relationship between the power module PM and the capacitor Cap will be described. Here, an example of the arrangement relationship when the number of power modules PM used is 6 and the number of capacitors Cap used is 24, that is, the number of capacitors used is 4 times the number of power modules PM used. explain.

  The 24 capacitors Cap are arranged along the common current path 10 at equal intervals, that is, symmetrically. The six power modules PM are disposed between the capacitors Cap and Cap. The specific arrangement of each power module PM is as follows.

Arranged between the power modules PM1... Capacitors Cap1 and 24 Power module PM2. Arranged between the capacitors Cap22 and 23 Power module PM3. Arranged between the capacitors Cap16 and 17 Power module PM4. Arranged between the power modules PM5 ·· capacitors Cap8 and 9 Arranged between the power modules PM6 ·· capacitors Cap6 and 7 The arrangement position of each power module PM is set by six virtual partition lines L. The six virtual partition lines L divide the 24 capacitors Cap into 12 equal parts. Each virtual partition line L is set at an intermediate position between predetermined capacitors Cap and Cap facing each other at the center O of the common current path 10. And each power module PM is arrange | positioned in the intermediate position between one capacitor | condenser Cap and Cap on each virtual partition line L. FIG.

  Here, the power module PM1 is disposed between the capacitors Cap1 and 24, and the capacitors Cap12 and 13 that are paired with the power module PM1 are set as a first capacitor group. In addition, the power module PM3 is disposed between the other capacitors Cap16 and 17, and the capacitors Cap4 and 5 that are paired with the power module PM3 serve as a second capacitor group. The first capacitor group and the second capacitor group are not arranged at the same position on the common current path 10.

  Therefore, in the power conversion device 1 of the present embodiment, when the capacitor Cap is used more than the power module PM, even if resonance occurs in the capacitor Cap, the capacitor Cap that resonates in one power module PM1 and the other power Since resonance interference with the capacitor Cap resonating in the module PM3 can be suppressed, an increase in power loss can be prevented.

  As described above, when 24 capacitors Cap and 6 power modules PM are arranged along the common current path 10, the magnitude of resonance generated in each capacitor Cap is set uniformly. This will be described with reference to FIG.

  When the power conversion device 1 is driven, each capacitor Cap resonates. Here, the power module PM1 is close to the capacitors Cap1 and 24. Therefore, the capacitors Cap1 and 24 and the capacitors Cap13 and 12 facing the capacitor Cap1 and 24 at the center O of the common current path 10 have the same magnitude of the resonance A.

  In addition, the power module PM2 is close to the capacitors Cap22 and Cap23. Therefore, the capacitors Cap22, 23 and the capacitors Cap10, 11 facing the capacitor Cap22, 23 at the center O of the common current path 10 have the same magnitude of the resonance B.

  Further, the power module PM3 is close to the capacitors Cap16 and 17. Therefore, the capacitors Cap16 and 17 and the capacitors Cap4 and 5 facing the capacitor Cap16 and 17 at the center O of the common current path 10 have the same magnitude of the resonance C.

  Further, the power module PM4 is close to the capacitors Cap14 and 15. Therefore, the capacitors Cap14 and 15 and the capacitors Cap2 and 3 facing this at the center O of the common current path 10 have the same magnitude of the resonance D.

  Further, the power modules PM5 are close to the capacitors Cap8 and Cap9. Therefore, the capacitors Cap8 and 9 and the capacitors Cap20 and 21 facing the capacitor Cap20 and 21 at the center O of the common current path 10 have the same magnitude of the resonance E.

  Further, the power module PM6 is close to the capacitors Cap6 and Cap7. Therefore, the capacitors Cap6 and 7 and the capacitors Cap18 and 19 facing the capacitor Cap6 and 7 at the center O of the common current path 10 have the same magnitude of the resonance F.

  Here, since all the six power modules PM are the same, the magnitudes of the resonances A to F generated in the capacitors Cap are uniform. For this reason, the current flowing through each capacitor Cap becomes uniform. Therefore, in the power conversion device 1 of the present embodiment, an increase in power loss can be prevented even if resonance occurs in the capacitor Cap when the capacitor Cap is used more than the power module PM.

  Moreover, in the power converter device 1 of this Embodiment, it comprised so that the alternating current of each phase might be output by two power modules PM. Therefore, the power conversion device 1 according to the present embodiment is more efficient in converting the DC current of each phase into the exchange current than when the AC current of each phase is output by one power module PM. Can be improved.

  Moreover, in the power converter device 1 of this Embodiment, power module PM1, 2 is arrange | positioned adjacently. Furthermore, the power modules PM3 and 4 are disposed adjacent to each other, and the power modules PM5 and 6 are disposed adjacent to each other.

  That is, in the power converter device 1 of the present embodiment, two adjacent power modules PM are used when outputting alternating current of each phase. Therefore, in the power conversion device 1 of the present embodiment, when outputting the alternating current of each phase, the power module PM for each phase is compared with the case of using two power modules PM that are not adjacent to each other. Since the connection work with the common current path 10 is facilitated, the work efficiency of the manufacturing work can be increased.

  Further, in the power conversion device 1 of the present embodiment, both power modules PM and PM drive circuits PMD are arranged between two adjacent power modules PM and PM. Therefore, in the power conversion device 1 of the present embodiment, the connection work between the power module PM and the drive circuit for each phase is performed as compared with the case where the drive circuit is arranged between two power modules PM that are not adjacent to each other. It becomes possible to make it easy. Therefore, in the power converter device 1 of this Embodiment, the work efficiency of manufacturing work can further be improved.

  Moreover, in the power converter device 1 of this Embodiment, since the ceramic capacitor was used for the capacitor, size reduction can be achieved. Therefore, when power converter 1 of this embodiment is installed in a vehicle, an installation space can be easily secured.

  In the present embodiment, the power module PM5 is disposed between the capacitors Cap8 and 9, and the power module PM6 is disposed between the capacitors Cap6 and 7.

  However, for example, the power module PM5 may be disposed between the capacitors Cap20 and 21 and the power module PM6 may be disposed between the capacitors Cap18 and 19 as shown by a one-dot chain line in FIG.

  That is, even if the two arrangement positions of the six power modules PM are changed to the opposite sides at the center O of the common current path 10, the eight capacitors Cap ( The magnitudes of the resonances E and F generated in the capacitors Cap 6 to 9 and 18 to 21) are not changed. Of course, the arrangement position of each power module PM is not limited to the position shown in FIG. 1, and may be arranged at an intermediate position between one capacitor Cap and Cap on each virtual partition line L.

Second embodiment:
FIG. 3 is a schematic diagram of the power conversion device 2 showing the second embodiment of the present invention. The power conversion device 2 of the present embodiment includes a common current path 10, six power modules PM, twelve capacitors Cap, and three drive circuits PMD. The function of each component is as described in the first embodiment. Here, an example of the arrangement relationship when the number of power modules PM used is 6 and the number of capacitors Cap used is 12, that is, the number of capacitors used is twice the number of power modules PM used. explain.

  The twelve capacitors Cap are arranged at equal intervals along the common current path 10. The six power modules PM are disposed between the capacitors Cap and Cap. The specific arrangement of each power module PM is as follows.

Arranged between the power modules PM1,... Capacitors Cap1 and 12 Arranged between the power modules PM2,... Capacitors Cap11 and 12, between the power modules PM3,. Arranged between the power modules PM5... Capacitors Cap4 and 5 Arranged between the power modules PM6... Capacitors Cap3 and 4 The arrangement position of each power module PM is set by six virtual partition lines L. The six virtual partition lines L divide the 12 capacitors Cap into 12 equal parts. Each virtual partition line L is set at an intermediate position between predetermined capacitors Cap and Cap facing each other at the center O of the common current path 10. And each power module PM is arrange | positioned in the intermediate position between one capacitor | condenser Cap and Cap on each virtual partition line L. FIG.

  As described above, when twelve capacitors Cap and six power modules PM are arranged along the common current path 10, the magnitudes of resonances generated in the capacitors Cap are all set uniformly. This will be described with reference to FIG.

  When the power converter 2 is driven, each capacitor Cap resonates. Here, the power module PM1 is close to the capacitors Cap1 and Cap12. Therefore, the capacitors Cap 1 and 12 and the capacitors Cap 7 and 6 facing this at the center O of the common current path 10 have the same magnitude of the resonance A.

  Further, the power module PM2 is close to the capacitors Cap11 and Cap12. Therefore, the capacitors Cap 11 and 12 and the capacitors Cap 5 and 6 facing this at the center O of the common current path 10 have the same magnitude of the resonance B.

  Further, the power modules PM3 are close to the capacitors Cap8 and Cap9. Therefore, the capacitors Cap 8 and 9 and the capacitors Cap 2 and 3 facing the capacitor Cap 8 and 9 at the center O of the common current path 10 have the same magnitude of the resonance C.

  In addition, the power module PM4 is close to the capacitors Cap7 and Cap8. Accordingly, the capacitors Cap7 and 8 and the capacitors Cap1 and Cap2 facing the capacitors Cap1 and 2 at the center O of the common current path 10 have the same magnitude of the resonance D.

  Further, the power modules PM5 are close to the capacitors Cap4 and Cap5. Therefore, the capacitors Cap4 and 5 and the capacitors Cap10 and 11 facing the capacitors Cap10 and 11 at the center O of the common current path 10 have the same magnitude of the resonance E.

  Further, the power modules PM6 are close to the capacitors Cap3 and Cap4. Therefore, the capacitors Cap3 and 4 and the capacitors Cap9 and 10 facing this at the center O of the common current path 10 have the same magnitude of the resonance F.

  Here, since all the six power modules PM are the same, the magnitudes of the resonances A to F generated in the capacitors Cap are uniform. Therefore, the current flowing through each capacitor Cap becomes uniform. Therefore, power converter 2 of this embodiment can prevent an increase in power loss even if resonance occurs in capacitor Cap when capacitor Cap is used more than power module PM.

  In the present embodiment, the power module PM5 is disposed between the capacitors Cap4 and 5, and the power module PM6 is disposed between the capacitors Cap3 and Cap4.

  However, for example, the power module PM5 may be disposed between the capacitors Cap10 and 11, and the power module PM6 may be disposed between the capacitors Cap9 and 10, as indicated by a one-dot chain line in FIG.

  That is, even if the two arrangement positions of the six power modules PM are changed to the opposite sides at the center O of the common current path 10, the six capacitors Cap ( The magnitudes of the resonances E and F generated in the capacitors Cap3 to 5 and 9 to 11) do not change. Of course, the arrangement position of each power module PM is not limited to the position shown in FIG. 3, and may be arranged at an intermediate position between one capacitor Cap and Cap on each virtual partition line L.

Third embodiment:
FIG. 5 is a schematic diagram of a power conversion device 3 showing a third embodiment of the present invention. The power conversion device 3 of the present embodiment includes a common current path 10, one power module PM, and two capacitors Cap. The function of each component is as described in the first embodiment. Here, the arrangement relationship when the number of power modules PM used is one and the number of capacitors Cap used is two will be described.

  The two capacitors Cap are arranged along the common current path 10. The power module PM is disposed between both capacitors Cap and Cap. Thereby, the magnitude | size of the resonance which generate | occur | produces in both the capacitors Cap and Cap is set uniformly. This will be described below.

  When the power converter 3 is driven, both capacitors Cap and Cap resonate. Here, since both the capacitors Cap and Cap are both affected by the power module PM, the magnitude of the resonance A generated in both the capacitors Cap and Cap is uniform. Therefore, the currents flowing through both capacitors Cap and Cap become uniform. Therefore, power converter 3 of this embodiment can prevent an increase in power loss even if resonance occurs in capacitor Cap when capacitor Cap is used more than power module PM.

  Note that the arrangement position of the power module PM may be set between the opposite capacitors Cap and Cap, as shown by a one-dot chain line in FIG. Further, the arrangement positions of both capacitors Cap and Cap may be set in a symmetric or asymmetric manner along the common current path 10.

Fourth embodiment:
FIG. 6 is a schematic diagram of a power conversion device 4 showing a fourth embodiment of the present invention. The power conversion device 4 according to the present embodiment includes a common current path 10, one power module PM, and four capacitors Cap. The function of each component is as described in the first embodiment. Here, the arrangement relationship when the number of power modules PM used is one and the number of capacitors Cap used is four will be described.

  The four capacitors Cap are arranged at equal intervals along the common current path 10. The power module PM is disposed at an intermediate position between the capacitors Cap2 and Cap3. Thereby, the magnitude of resonance generated in each capacitor Cap is set uniformly. This will be described below.

  When the power conversion device 4 is driven, each capacitor Cap resonates. Here, the capacitors Cap <b> 2 and 3 are close to the power module PM. Therefore, the capacitors Cap 2 and 3 and the capacitors Cap 4 and 1 facing this at the center O of the common current path 10 have the same magnitude of the resonance A. That is, the resonance magnitudes of all four capacitors Cap are uniform. Therefore, the current flowing through each capacitor Cap is uniform.

  Therefore, power converter 4 of this embodiment can prevent an increase in power loss even when resonance occurs in capacitor Cap when capacitor Cap is used more than power module PM. Note that the arrangement position of the power module PM may be set between other capacitors Cap and Cap, as shown by a one-dot chain line in FIG.

Fifth embodiment:
FIG. 7 is a schematic diagram of a power conversion device 5 showing a fifth embodiment of the present invention. The power conversion device 5 of the present embodiment includes a common current path 10, two power modules PM, and four capacitors Cap. The function of each component is as described in the first embodiment. Here, the arrangement relationship when the number of power modules PM used is two and the number of capacitors Cap used is four will be described.

  The four capacitors Cap are arranged at equal intervals along the common current path 10. The power module PM1 is arranged at an intermediate position between the capacitors Cap2 and Cap3. Further, the power module PM2 is disposed at an intermediate position between the capacitors Cap1 and Cap4. Thereby, the magnitude of resonance generated in each capacitor Cap is set uniformly. This will be described below.

  When the power converter 5 is driven, each capacitor Cap resonates. Here, the capacitors Cap2 and 3 are located close to the power module PM1. Therefore, the capacitors Cap 2 and 3 and the capacitors Cap 4 and 1 facing this at the center O of the common current path 10 have the same magnitude of the resonance A.

  Furthermore, the capacitors Cap1 and 4 are close to the power module PM2. For this reason, the capacitors Cap1 and 4 and the capacitors Cap3 and 2 facing the capacitor Cap3 and 2 at the center O of the common current path 10 have the same magnitude of the resonance B.

  Since the two power modules PM are the same, the magnitudes of the resonances A and B generated in each capacitor Cap are uniform. Therefore, the current flowing through each capacitor Cap becomes uniform. Therefore, power converter 5 of this embodiment can prevent an increase in power loss even when resonance occurs in capacitor Cap when capacitor Cap is used more than power module PM.

  In the present embodiment, two power modules PM are arranged at an intermediate position between any two capacitors Cap and Cap, or two adjacent capacitors Cap, as shown by a one-dot chain line in FIG. , Cap may be arranged adjacent to each other. That is, even if the arrangement positions of the two power modules PM are changed, all four capacitors Cap are affected by the two power modules PM, so the magnitude of resonance generated in each capacitor Cap is does not change.

  As mentioned above, although embodiment concerning this invention was illustrated, these embodiments do not limit the content of this invention. Various modifications can be made without departing from the scope of the claims of the present invention.

For example, in each of the embodiments described above, a case has been described in which the number of power modules PM used and the number of capacitors Cap used are set as follows.
(1) The number of power modules PM used is 1 ··· The number of capacitors Cap used is 2 or 4 (2) The number of power modules PM used is 2 · · The number of capacitors Cap used is 4 (3) The number of power modules PM used is six. The number of capacitors Cap used is 12 or 24. However, the number of power modules PM used and the number of capacitors Cap used need not be limited to the above numbers. When the number of power modules PM used is three or more, the number of capacitors Cap used is set to be twice or four times the number of power modules PM used, and the first embodiment or the second If the power module PM and the capacitor Cap are arranged as described in the embodiment, since the current flowing through each capacitor Cap becomes uniform, an increase in power loss can be prevented.

  When the number of capacitors Cap used is less than the number of power modules PM used, the number of power modules PM used is not particularly limited when the number of capacitors Cap used is one or two. When the number of capacitors Cap used is three or more, the number used is set to an integral multiple of the number of power modules PM used. In other words, the number of capacitors Cap used is set to 1 / N with respect to the number N of power modules PM used (N is an integer). In that case, the number of capacitors used is arranged along the common current path 10, and the same number of power modules PM is arranged between the capacitors.

DESCRIPTION OF SYMBOLS 1 Power converter 2 Power converter 3 Power converter 4 Power converter 5 Power converter 10 Common current path Cap Capacitor PM Power module PMD Power module drive circuit A to F Resonance L Virtual partition line

Claims (4)

An annular common current path for passing a DC current supplied from a DC power supply, a capacitor connected to the common current path, and the capacitor connected to the capacitor via the common current path to convert the DC current into an AC current In a power conversion device having a power module that outputs
The capacitor is disposed along the common current path, the power module is disposed between the capacitors, and a pair of capacitor groups on the common current path is defined as a first capacitor group, on the common current path. The power module is arranged between other capacitors, and a pair of capacitors on the common current path is set as a second capacitor group, and the first capacitor group and the second capacitor group are set on the common current path. The power converter characterized by having arrange | positioned in different positions.   The power conversion device according to claim 1, wherein at least one phase of alternating current is output by a plurality of power modules.   The power converter according to claim 2, wherein the plurality of power modules are a plurality of adjacent power modules.   4. The power conversion device according to claim 3, wherein a drive circuit for these power modules is disposed between a plurality of adjacent power modules.

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