JP2016158426A - Cooling structure for power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cooling structure for a power conversion device that is small-sized and lightweight further by forming a bus coolant path from a power supply bus bar.SOLUTION: In a cooling structure 8 for a power conversion device 1, power is supplied to a power conversion part 4 and an inverter part 6 that perform power conversion, via a first bus bar 71 and a second bus bar 72, and cooling is performed by supplying a coolant to the power conversion part 4 and the inverter part 6. A connection with an external conductor in a coaxial shape is performed by the first bus bar 71 in a hollow cylindrical shape and the second bus bar 72 in a hollow cylindrical shape disposed coaxially outside of the first bus bar 71. The coolant flows to at least one of a bus coolant path 811 formed between the first bus bar 71 and the second bus bar 72 and a central coolant path 813 formed in a hollow internal part of the first bus bar 71.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a cooling structure that cools by supplying a refrigerant to a power converter.

  In recent years, a hybrid vehicle having an engine and a motor as a driving source for driving and an electric vehicle having only a motor are rapidly spreading, and various types of driving devices have been put into practical use. As the motor, a three-phase synchronous motor generator is frequently used, and when driving, the driving wheel is driven by power supplied from an in-vehicle battery, and during braking, regenerative power generation is performed to charge the battery. Here, although the vehicle speed can be controlled by variably adjusting the drive voltage supplied to the motor, the charging voltage of the battery fluctuates with time. For this reason, it is common to provide a power conversion device between the motor and the battery, and to perform power conversion from the battery to the motor during power running and from the motor to the battery during braking. The power conversion device includes a power conversion unit having a capacitor, a reactor, and a switching element. This type of power conversion device is not limited to in-vehicle use, and is widely used in distributed power generation facilities.

  Patent Documents 1 to 3 disclose power conversion devices (for example, power semiconductor modules (switching elements), capacitor devices, reactor devices, converter devices, and inverter devices) suitable for in-vehicle applications. These devices employ a hollow cylindrical structure to reduce the size and weight, and improve the mountability to a vehicle. The high-voltage side and low-voltage side of the DC circuit are arranged inside and outside the coaxial line, and the AC three-phase circuit is arranged rotationally symmetrically. Further, the generation of noise is suppressed in consideration of lead length reduction and bus bar configuration. ing.

JP 2009-88466 A JP 2013-197486 A JP 2014-216455 A

  In the inverter device disclosed in Patent Document 2, the temperature rise in the power conversion unit having the switching element becomes severe as the size and weight are reduced. For this reason, a special cooling structure is required in which a cooling jacket is disposed in the vicinity of the switching element and the cooling water is circulated inside the cooling jacket. However, the addition of the cooling jacket is a restriction on the layout design inside and around the apparatus, and thus it has been difficult to further reduce the size and weight.

  Even if a cooling jacket is added, the cooling performance is limited by the thermal resistance of the jacket wall surface. If the cooling performance is restricted, the internal temperature of the apparatus rises, and there is a risk that the service life and reliability may be reduced. Such restrictions on the layout design and cooling performance of the cooling structure are not limited to the inverter device disclosed in Patent Document 2, but are common to the power conversion device.

  The present invention has been made in view of the problems of the above-described background art, and provides a cooling structure for a power conversion device that realizes further reduction in size and weight by forming a bus refrigerant path using a power supply bus bar. Is a problem to be solved.

  In the cooling structure of the power conversion device of the present invention that solves the above problems, power is supplied to the power conversion unit that performs power conversion via the first bus bar and the second bus bar, and the power conversion unit A cooling structure of a power conversion device that cools by supplying a refrigerant, wherein the first bus bar having a hollow cylindrical shape and a hollow cylindrical second bus bar disposed on the coaxial outer side of the first bus bar have a coaxial shape. The refrigerant is connected to at least one of a bus refrigerant path formed between the first bus bar and the second bus bar and a central refrigerant path formed inside the hollow of the first bus bar. Flowing.

  According to this, the refrigerant path which supplies a refrigerant | coolant using the 1st bus bar and 2nd bus bar for power supply can be formed, and at least one part of the exclusive member which forms a refrigerant path can be abbreviate | omitted. Therefore, restrictions on layout design are reduced, and further reduction in size and weight of the power conversion device is realized.

It is an electric circuit diagram which illustrates the composition of the power converter which carries out the present invention, the upper part shows the circuit composition of the converter part, and the lower part shows the circuit composition of the inverter part. It is sectional drawing of the one side with respect to the central axis explaining the internal structure of a power converter device. FIG. 3 is an arrow view showing a portion corresponding to 60 ° of the central angle of the cross section of the first layer to the sixth layer shown in FIG. 2. It is sectional drawing of one side with respect to the central axis which shows the cooling structure of the power converter device of 1st Embodiment typically and demonstrates the effect | action. It is sectional drawing of one side with respect to the central axis which shows the cooling structure of the power converter device of 2nd Embodiment typically, and demonstrates the effect | action. It is side surface sectional drawing which shows the isolation | separation state of the connection part in 2nd Embodiment. It is a ZZ arrow line view of Drawing 6, and shows the section shape orthogonal to the central axis of the 1st bus bar. It is side surface sectional drawing which shows the connection state of a connection part.

  First, the circuit configuration and structure of the power conversion apparatus 1 that implements the present invention will be described with reference to FIGS. FIG. 1 is an electric circuit diagram illustrating the configuration of a power converter 1 that implements the present invention. The power conversion device 1 boosts the power supply voltage Vd1 of the DC power supply 91 to generate a DC output voltage Vd2, converts the DC output voltage Vd2 into an AC output voltage Va, and outputs the AC output voltage Va to the AC load 99. The upper side of FIG. 1 is a circuit configuration of a converter unit 1CV corresponding to a boosting unit that performs electrical boosting, and the lower side of FIG. 1 is a circuit configuration of an inverter unit 6 that drives an AC load.

  The power conversion device 1 is composed of a converter unit 1CV and an inverter unit 6 and a bus bar set 7 for supplying power. The bus bar set 7 includes a first bus bar 71 on the high pressure side and a second bus bar 72 on the low pressure side.

  The converter unit 1CV is configured by an input capacitor 2, a reactor 3, a power conversion unit 4, and an output capacitor 5. The first terminal 211 of the input capacitor 2 is electrically connected to the high voltage side terminal 91 </ b> P of the DC power supply 91 via the internal conductor 921. The second terminal 212 of the input capacitor 2 is electrically connected to the low voltage side terminal 91N of the DC power supply 91 via the outer conductor 922. The third terminal 311 on the input side of the reactor 3 is electrically connected to the first terminal 211 of the input capacitor 2. The fourth terminal 312 on the output side of the reactor 3 is electrically connected to the high voltage side intermediate electrode 32m.

  The power conversion unit 4 includes a circuit including an upper switch unit 41 and a lower switch unit 42. The upper switch unit 41 and the lower switch unit 42 are configured by parallel connection of switching elements 41S and 42S and diodes 41D and 42D, respectively. Examples of the switching elements 41S and 42S include, but are not limited to, regular hexagonal plate-shaped power semiconductor modules and publicly known IGBT elements disclosed in Patent Document 1 by the applicant of the present application.

  The collector terminal 41C of the high voltage side switching element 41S and the cathode terminal 41K of the diode 41D are electrically connected to the fifth terminal 511 of the output capacitor 5 via the high voltage side output electrode 43 on the high voltage side. The emitter terminal 41E of the switching element 41S and the anode terminal 41A of the diode 41D are electrically connected to the high-voltage side intermediate electrode 32m.

  On the other hand, the collector terminal 42C of the low-voltage side switching element 42S and the cathode terminal 42K of the diode 42D are electrically connected to the high-voltage side intermediate electrode 32m. The emitter terminal 42E of the switching element 42S and the anode terminal 42A of the diode 42D are electrically connected to the second terminal 212 of the input capacitor 2 and the sixth terminal 512 of the output capacitor 5 via the low-voltage common electrode 24. Connected on the side. The fifth terminal 511 and the sixth terminal 512 of the output capacitor 5 are electrically connected to the inverter unit 6.

  The inverter unit 6 includes a three-phase upper switch unit 61U, 61V, 61W and a lower switch unit 62U, 62V, 62W. Each phase upper side switch part 61U, 61V, 61W and each phase lower side switch part 62U, 62V, 62W are comprised by the parallel connection of switching element 61S, 62S and diode 61D, 62D, respectively. Examples of the switching elements 61S and 62S include, but are not limited to, regular hexagonal plate-shaped power semiconductor modules and publicly known IGBT elements disclosed in Patent Document 1 by the present applicant.

  As shown in FIG. 1, since the circuit configuration of the inverter unit 6 is the same for the U phase, the V phase, and the W phase, the U phase is taken as an example, and the description of the V phase and the W phase is omitted. To do. The collector terminal 61C of the switching element 61S of the U-phase upper switch unit 61U and the cathode terminal 61K of the diode 61D are electrically connected to the fifth terminal 511 of the output capacitor 5 of the converter unit 1CV. Further, the emitter terminal 61E of the switching element 61S of the U-phase upper switch unit 61U and the anode terminal 61A of the diode 61D are electrically connected to the U-phase inverter output electrode 63U.

  On the other hand, the collector terminal 62C of the switching element 62S of the U-phase lower switch unit 62U and the cathode terminal 62K of the diode 62D are electrically connected to the U-phase inverter output electrode 63U. The emitter terminal 62E of the switching element 62S and the anode terminal 62A of the diode 62D of the U-phase lower switch unit 62U are electrically connected to the sixth terminal 512 of the output capacitor 5. Each phase inverter output electrode 63U, 63V, 63W is electrically connected to AC load 99.

  Next, the structure of the power conversion device 1 will be described. FIG. 2 is a sectional view on one side with respect to the central axis CL for explaining the internal structure of the power conversion device 1. FIG. 3 is a view taken in the direction of the arrow showing the central angle corresponding to 60 ° of the cross section of the first to sixth layers shown in FIG. The input capacitor 2, the reactor 3, and the output capacitor 5 each have a hollow cylindrical shape.

  The bus bar set 7 on the input side connects the converter unit 1CV to the DC power supply 91 via a coaxial outer conductor. The bus bar set 7 is configured such that a hollow cylindrical first bus bar 71 and a second bus bar 72 are arranged coaxially inside and outside around a central axis CL. The first bus bar 71 and the second bus bar 72 are formed using a conductive material such as copper or aluminum. The second bus bar 72 arranged on the coaxial outer side may or may not be grounded to the frame ground. When not grounding, it is preferable to arrange a cylindrical frame ground on the outer periphery of the second bus bar 72. The first bus bar 71 and the second bus bar 72 have flange-like connection portions 711 and 721 in which end portions on the side close to the converter portion 1CV are expanded radially outward, respectively.

  A reactor 3 is disposed on the inner diameter side of the input capacitor 2. A power conversion unit 4 is disposed on the inner diameter side of the reactor 3. That is, the input capacitor 2, the reactor 3, and the power conversion unit 4 have a coaxial inner / outer triple structure around the central axis CL. The arrangement order of the triple structure can be changed in addition to the above, for example, the reactor 3, the input capacitor 2, and the power conversion unit 4 may be arranged from the coaxial outer side to the inner side. The output capacitor 5 and the inverter unit 6 are arranged in a coaxial inner / outer duplex structure side by side in the axial direction of the coaxial inner / outer triple structure (aligned on the lower side in FIG. 2). The output capacitor 5 is arranged side by side in the axial direction of the input capacitor 2 and the reactor 3. The inverter unit 6 is arranged side by side in the axial direction of the power conversion unit 4.

  The input capacitor 2 and the output capacitor 5 can be, for example, hollow cylinder capacitors disclosed in Patent Document 2 by the applicant of the present application. That is, the input capacitor 2 and the output capacitor 5 include an inner peripheral cylindrical portion, a one-pole connecting portion having one side surface portion extending from one end portion of the inner peripheral cylindrical portion to the outer peripheral side, an inner peripheral cylindrical portion and a center. The other electrode connecting portion having an outer peripheral cylindrical portion coaxially arranged on the axis and the other side surface portion extending from the other end of the outer peripheral cylindrical portion to the inner peripheral side, and one electrode connected to the one electrode connecting portion Plate, the other electrode plate facing the one electrode plate and connected to the other electrode connecting portion, and the electrostatic capacitance portion having a dielectric interposed between the one electrode plate and the other electrode plate, It can be set as the hollow cylindrical capacitor | condenser by which the electrostatic capacitance part is accommodated in the annular space formed between a cylinder part, one side part, an outer peripheral cylinder part, and another side part.

  As shown in FIG. 2, the input capacitor 2 and the output capacitor 5 have a hollow cylindrical shape and have the same outer diameter. The input capacitor 2 and the output capacitor 5 share the outer peripheral electrode 23 and the low-voltage side common electrode 24. The outer peripheral electrode 23 has a cylindrical shape and is disposed on the outer periphery of the main body of the input capacitor 2 and the output capacitor 5. The outer peripheral electrode 23 corresponds to the housing portion of the present invention. The low-voltage side common electrode 24 has an annular shape, and is connected to a substantially intermediate position in the axial direction of the inner surface of the outer peripheral electrode 23. The low-voltage side common electrode 24 is disposed between the input capacitor 2 and the output capacitor 5 and extends radially inward from the output capacitor 5.

  A first terminal 211 is formed on the surface of the main body of the input capacitor 2 away from the output capacitor 5 (upper surface in FIG. 2). The first terminal 211 is connected in contact with the flange-shaped electrode 711 of the first bus bar 71. Further, the first terminal 211 is bent toward the inner peripheral side of the hollow cylindrical shape, and has a connection surface 25 on the inner periphery. A second terminal 212 is formed on the surface of the main body of the input capacitor 2 that faces the output capacitor 5 (the lower surface in FIG. 2). The second terminal 212 is disposed in contact with the low-voltage side common electrode 24 and is electrically connected to the second bus bar 72 via the outer peripheral electrode 23 and the flange-shaped electrode 721.

  The reactor 3 can be, for example, a hollow cylindrical reactor device disclosed in Patent Document 3 by the applicant of the present application. That is, the reactor 3 is a reactor device that includes an inductance element having a coil 35 wound with a conductor covered with an insulation coating around the central axis CL on the forward path, and a return conductor on the return path. The axis CL can be a hollow cylindrical or annular shape, and the return conductor can be a hollow cylindrical reactor device that has a cylindrical shape with the central axis CL in common and is arranged on the coaxial outer peripheral side of the inductance element. Here, the outer peripheral electrode 23 plays the role of the return conductor. In the first embodiment, the coil 35 is formed in a toroidal shape around the central axis CL, and a core 36 having a gap is disposed outside the coil 35.

  The third terminal 311 of the reactor 3 is provided on the outer peripheral surface of the hollow cylindrical body. The third terminal 311 is disposed so as to face the connection surface 25 of the first terminal 211 of the input capacitor 2 on the inside and outside of the same axis and contact each other, and is directly electrically connected without using a lead wire. The fourth terminal 312 of the reactor 3 is provided on the inner peripheral surface of the main body. An annular high-voltage intermediate electrode 32m is disposed inside the fourth terminal 312. The high-voltage intermediate electrode 32m has a connection surface 33 on the outer periphery. The fourth terminal 312 and the connection surface 33 of the high-voltage side intermediate electrode 32m are arranged opposite to each other on the inside and outside of the coaxial axis, contact each other, and are directly electrically connected.

  The power conversion unit 4 can be, for example, a hollow cylindrical power conversion unit used in the hollow cylindrical converter device disclosed in Patent Document 3 by the applicant of the present application. The power converter 4 is disposed along the axial direction of the central axis CL together with the electrodes to be connected. That is, in order from the upper side to the lower side shown in FIG. 2, the high-voltage side output electrode 43, the upper switch unit 41, the high-voltage side intermediate electrode 32 m, the lower-side switch unit 42, the channel material 44, and the low-voltage side common electrode 24 Has been placed. The high voltage side output electrode 43 is bent in the axial direction on the inner peripheral side and extends to the inside of the inverter unit 6.

  Here, the switching elements 41S and 42S of the upper side switch part 41 and the lower side switch part 42 are arranged in a state of being spaced apart and arranged in parallel in the axial direction at positions close to the center of the outer peripheral electrode 23 (accommodating part). The switching elements 41S and 42S are plate-shaped, and collector terminals 41C and 42C are formed on the front surface, and gate terminals 41G and 42G and emitter terminals 41E and 42E are formed on the back surface. The collector terminal 41C of the high voltage side switching element 41S is directly electrically connected to the high voltage side output electrode 43 using soldering. The emitter terminal 41E of the switching element 41S is also electrically connected directly to the high-voltage side intermediate electrode 32m using soldering. The solder material used for soldering is preferably a high melting point type, but is not limited to this (the same applies to other soldering locations described below). The high-voltage side diode 41D omitted in FIG. 2 is disposed and electrically connected between the high-voltage side output electrode 43 and the high-voltage side intermediate electrode 32m.

  On the other hand, the collector terminal 42C of the low-voltage side switching element 42S is directly electrically connected to the high-voltage side intermediate electrode 32m using soldering. The emitter terminal 42E of the switching element 42S is electrically connected to the low-voltage side common electrode 24 using a channel material 44 having a U-shaped cross section. The low-voltage side diode 42 </ b> D omitted in FIG. 2 is disposed and electrically connected between the high-voltage side intermediate electrode 32 m and the low-voltage side common electrode 24.

  A sixth terminal 512 is formed on the surface of the main body of the output capacitor 5 facing the input capacitor 2 (upper surface in FIG. 2). The sixth terminal 512 is disposed in contact with the low voltage side common electrode 24 and is electrically connected to the power conversion unit 4 and the inverter unit 6 via the low voltage side common electrode 24. That is, the low voltage side common electrode 24 also serves as the low voltage side inverter input electrode. A fifth terminal 511 is formed on the surface of the main body of the output capacitor 5 away from the input capacitor 2 (lower in FIG. 2). The fifth terminal 511 is in contact with and electrically connected to the high-voltage side inverter input electrode 53.

  The high-voltage side inverter input electrode 53 has an annular shape and extends to the inside in the radial direction from the output capacitor 5. The inverter unit 6 is electrically connected to the inner periphery of the high-voltage side inverter input electrode 53. The inner edge of the high-voltage side inverter input electrode 53 is electrically connected to the end portion extending in the axial direction of the high-voltage side output electrode 43 of the power conversion unit 4.

The inverter unit 6 can be, for example, an inverter device disclosed in Patent Document 1 or Patent Document 2 by the applicant of the present application. That is, the inverter unit 6 has six equilateral triangular power semiconductor modules (switching elements) arranged in a regular hexagonal shape, and these are arranged in three-phase upper switch units 61U, 61V, 61W and lower switch units 62U, 62V, 62W. It can be set as the inverter apparatus of the structure used for each. The switching elements 61S of the upper-side switch units 61U, 61V, 61W are arranged rotationally symmetrically at a 120 ° pitch around the central axis CL. Similarly, the switching elements 62S of the lower phase switch units 62U, 62V, and 62W are also disposed rotationally symmetrically at a 120 ° pitch around the central axis CL.

  Moreover, the inverter part 6 is arrange | positioned along the axial direction of the central axis line CL with the electrode connected. That is, in order from the upper side to the lower side shown in FIG. 2, the low-voltage side common electrode 24 corresponding to the low-voltage side inverter input electrode, the channel material 64, the respective phase lower side switch parts 62U, 62V, 62W, and the inverter output electrode 63U. 63V, 63W, each phase upper side switch part 61U, 61V, 61W, and the high voltage side inverter input electrode 53 are arranged.

  Here, the switching elements 61S and 62S of each phase upper side switch part 61U, 61V, 61W and each phase lower side switch part 62U, 62V, 62W are arranged in the axial direction at positions close to the center of the outer peripheral electrode 23 (accommodating part). They are arranged in a state of being spaced apart and juxtaposed. The switching elements 61S and 62S are plate-shaped, and collector terminals 61C and 62C are formed on the front surface, and gate terminals 61G and 62G and emitter terminals 61E and 62E are formed on the back surface. And the collector terminal 61C of the switching element 61S of each phase upper side switch part 61U, 61V, 61W is electrically connected to the high voltage side inverter input electrode 53 directly using soldering. Further, the emitter terminal 61E of the switching element 61S is also electrically connected directly to each phase inverter output electrode 63U, 63V, 63W using soldering. The diode 61D of each phase upper side switch unit 61U, 61V, 61W omitted in FIG. 2 is disposed between and electrically connected to the high voltage side inverter input electrode 53 and each phase inverter output electrode 63U, 63V, 63W. ing.

  On the other hand, the collector terminal 62C of the switching element 62S of each phase lower side switch part 62U, 62V, 62W is electrically connected to each phase inverter output electrode 63U, 63V, 63W directly using soldering. The emitter terminal 62E of the switching element 62S is electrically connected to the low-voltage side common electrode 24 using a channel material 64 having a U-shaped cross section. The diode 62D of each phase lower side switch unit 62U, 62V, 62W omitted in FIG. 2 is arranged between each phase inverter output electrode 63U, 63V, 63W and the low voltage side common electrode 24 and is electrically connected. Has been.

  The three-phase inverter output electrodes 63U, 63V, 63W are arranged rotationally symmetrically at a 120 ° pitch around the central axis CL. Each phase inverter output electrode 63U, 63V, 63W is bent between the output capacitor 5 and the inverter unit 6, drawn out in the axial direction (downward in FIG. 2), and electrically connected to the AC load 99.

  An insulating member 941 is interposed between the flange-like connection part 711 of the first bus bar 71 and the flange-like connection part 721 of the second bus bar 72. Similarly, an insulating member 942 is inserted between the outer peripheral electrode 23 and the input capacitor 2, and an insulating member 943 is inserted between the outer peripheral electrode 23 and the output capacitor 5. Further, an insulating member 944 is inserted between the core 36 of the reactor 3 and the flange-like connecting portion 711, and an insulating member 945 is inserted between the core 36 and the low-voltage side common electrode 24. Further, an insulating member 946 is interposed between the flange-like connection portion 711 and the high-voltage side output electrode 43. By these insulating members 941 to 946, a predetermined insulating distance is secured and the insulating performance is maintained.

  In the first layer of FIG. 3, flange-like connecting portions 721 of the first bus bar 71 and the second bus bar 72 are shown. In the second layer, the flange-like connecting portion 711 of the first bus bar 71 is shown. In the third layer, a coaxial inner / outer triple structure of the input capacitor 2, the reactor 3, and the power conversion unit 4 (high voltage side switching unit 41) is shown. In the fourth layer, the low-voltage side common electrode 24 is shown. In the fifth layer, a coaxial internal / external double structure of the output capacitor 5 and the inverter unit 6 is shown. In the sixth layer, the fifth terminal 511 of the output capacitor 5 and the switching elements 61S of the upper phase switch units 61U, 61V, 61W of the inverter unit 6 are shown.

  Even if the DC power supply 91 is a battery and the power supply voltage Vd1 changes, the power conversion device 1 can generate the desired DC output voltage Vd2 by the variable boost function of the converter unit 1CV. Further, the power conversion device 1 can output the AC output voltage Va having a desired frequency and effective value to the AC load 99 by the inverter unit 6. In addition, the power conversion device 1 has a power conversion function in the reverse direction. That is, the power conversion apparatus 1 can charge the battery corresponding to the DC power supply 91 by converting the three-phase AC power input from the motor generator corresponding to the AC load 99 to DC.

  Then, the cooling structure 8 of the power converter device 1 of 1st Embodiment of this invention is demonstrated. FIG. 4 is a cross-sectional view on one side with respect to the central axis CL that schematically illustrates the operation of the cooling structure 8 of the power conversion device 1 of the first embodiment. The cooling structure 8 cools the power conversion unit 4 and the inverter unit 6 by supplying a refrigerant. The cooling structure 8 includes a bus refrigerant path 81 through which the refrigerant circulates, a main body refrigerant path 82, a pumping pump 85, a cooling device 86, and the like. The refrigerant is a fluid and may be any of a liquid phase, a gas phase, and a mixture of a liquid phase and a gas phase. Examples of the refrigerant include cooling oil, chlorofluorocarbon, carbon dioxide, and the like, but are not limited thereto.

  The bus refrigerant path 81 includes a cylindrical bus refrigerant path 811 and a radial bus refrigerant path 812. As shown in FIG. 4, a cylindrical bus refrigerant path 811 is formed by the cylindrical space between the first bus bar 71 and the second bus bar 72 constituting the bus bar set 7. Further, a radial bus refrigerant path 812 is formed between the high-pressure side flange-like connecting portion 711 and the low-pressure side flange-like connecting portion 721 that are spaced apart by the insulating member 941. The inner circumference of the radial bus refrigerant path 812 communicates with the cylindrical bus refrigerant path 811. A refrigerant introduction port 87 is formed in the middle of the second bus bar 72 in the axial direction. The refrigerant introduction port 87 communicates with the discharge port 851 of the pressure pump 85 while maintaining hermeticity using a pipe line (not shown). The electrical insulation between the second bus bar 72 and the pipeline is ensured by an insulator (not shown).

  The main refrigerant path 82 is formed by gaps between a plurality of members constituting the electric circuit and liquid holes 831 to 833 formed in the members. The main body refrigerant path 82 includes a reactor refrigerant path 821, which is a radial refrigerant path, a power converter inward refrigerant path 822, a power converter outward refrigerant path 823, an inverter inward refrigerant path 824, and an inverter outward refrigerant path 825, It is formed by a combination with an axial refrigerant path having an abbreviation code that allows these to communicate in order. The main body refrigerant path 82 will be described in detail below.

  The reactor refrigerant path 821 is formed inward in the radial direction between the high-pressure side flange-like connecting portion 711 and the core 36 of the reactor 3 that are spaced apart by the insulating member 944. A liquid hole 831 that communicates from the outer periphery of the radial bus refrigerant passage 812 to the outer periphery of the reactor refrigerant passage 821 is formed in the flange-like connection portion 711 on the high-pressure side. The size and number of the liquid holes 831 can be appropriately determined according to the required flow rate of the refrigerant (the same applies to liquid holes 832 and 833 described later).

  The power conversion unit inward refrigerant path 822 is formed inward in the radial direction between the high voltage side switching unit 41 and the high voltage side intermediate electrode 32 m of the power conversion unit 4. The inner circumference of the reactor refrigerant path 821 and the outer circumference of the power converter inward refrigerant path 822 are communicated with each other through an axial refrigerant path including refraction. The power conversion unit outward refrigerant path 823 is formed radially outward between the low pressure side switching unit 42 and the low pressure side common electrode 24. The inner periphery of the power converter inward refrigerant path 822 and the inner periphery of the power converter outward refrigerant path 823 are communicated with each other through an axial refrigerant path.

  The inverter inward refrigerant path 824 is formed inward in the radial direction between the low-pressure side common electrode 24 and the phase lower side switch portions 62U, 62V, 62W. A liquid hole 832 that communicates from the outer periphery of the power conversion portion outward refrigerant passage 823 to the outer periphery of the inverter inward refrigerant passage 824 is formed in the low-pressure side common electrode 24. The inverter outward refrigerant path 825 is formed radially outward between the phase inverter output electrodes 63U, 63V, 63W and the phase upper switch portions 61U, 61V, 61W. The inner circumference of the inverter inward refrigerant path 824 and the inner circumference of the inverter outer refrigerant path 825 are communicated with each other through an axial refrigerant path. A liquid hole 833 communicating from the outer periphery of the inverter outward refrigerant path 825 to the outside is formed in the high-voltage side inverter input electrode 53.

  As can be seen from the above description, the main body refrigerant path 82 is formed so that it can be drawn with a single stroke without crossing in a sectional view. Further, the main body refrigerant path 82 is formed by alternately combining the axial direction refrigerant path and the radial direction refrigerant path inside the power conversion unit 4 and the inverter unit 6. Therefore, the main body refrigerant path 82 can cool the switching elements 41S, 42S, 61S, 62S spaced apart in the axial direction by flowing them in a crank shape. In other words, the main body refrigerant path 82 causes the axially spaced switching elements 41S, 42S, 61S, 62S to flow while changing the direction in the radially inward and outward directions, and in the outer peripheral electrode 23 (in the accommodating portion). Can be cooled.

  The liquid hole 833 of the high-voltage inverter input electrode 53 communicates with the inlet 861 of the cooling device 86 while maintaining hermeticity using a pipe line (not shown). Note that the electrical insulation between the high-voltage inverter input electrode 53 and the pipe line is ensured by an insulator (not shown). The outflow port 862 of the cooling device 86 communicates with the suction port 852 of the pressure feed pump 85 by a direct connection structure or by using a pipe line (not shown). Thereby, a closed circulation path is formed. Various known devices can be appropriately used for the pressure pump 85 and the cooling device 86.

  Next, the effect | action of the cooling structure 8 of the power converter device 1 of 1st Embodiment comprised as mentioned above is demonstrated. When the power converter 1 is operated, heat loss is generated in the electric circuit. Since the input capacitor 2 and the output capacitor 5 generate little heat loss, natural cooling by air convection or the like is sufficient. On the other hand, the reactor 3, the power conversion unit 4, and the inverter unit 6 generate a considerable amount of heat loss, so that circulation of the refrigerant is necessary.

  As indicated by the white arrow A1 in FIG. 4, the heat loss generated in the switching element 41S on the high voltage side of the power converter 4 is transmitted to the high voltage output electrode 43 via soldering. Similarly, as indicated by the white arrow A2, the heat loss generated in the low-voltage side switching element 42S is transmitted to the high-voltage side intermediate electrode 32m via soldering. Thereby, the heat radiation surface area of the switching elements 41S and 42S of the power conversion unit 4 increases equivalently.

  Further, as indicated by the white arrow A3 in FIG. 4, the heat loss generated in the switching element 62S of each phase lower side switch unit 62U, 62V, 62W of the inverter unit 6 is output to each phase inverter through soldering. It is transmitted to the electrodes 63U, 63V, 63W. Similarly, as indicated by the white arrow A4, the heat loss generated in the switching elements 61S of the upper phase switch units 61U, 61V, 61W is transmitted to the high voltage side inverter input electrode 53 through soldering. Thereby, the heat radiation surface area of the switching elements 61S and 62S of the inverter unit 6 increases equivalently.

  In addition, the pumping pump 85 is also operated along with the operation of the power conversion device 1. The pressure feed pump 85 circulates by feeding the refrigerant. The refrigerant is introduced from the pressure pump 85 into the cylindrical bus refrigerant path 811 (shown by arrow F1 in FIG. 4) and flows to the radial bus refrigerant path 812 (shown by arrow F2). Then, the refrigerant flows into the reactor 3 through the liquid hole 831 (indicated by an arrow F3). The refrigerant flows through the reactor refrigerant path 821 inward in the radial direction, and cools by directly touching the core 36 (indicated by arrow F4).

  Subsequently, the refrigerant flows into the power conversion unit 4. The refrigerant flows in the power conversion portion inward refrigerant path 822 inward in the radial direction, and cools by directly touching the high-pressure side switching element 41S and the high-pressure side intermediate electrode 32m (indicated by arrow F5). Further, the refrigerant flows through the power conversion portion outward refrigerant path 823 radially outward and flows while directly touching the switching element 42S and the low-pressure side common electrode 24 to perform cooling (indicated by arrow F6).

  Thereafter, the refrigerant flows into the inverter unit 6 through the liquid hole 832. The refrigerant flows through the inverter inward refrigerant path 824 inward in the radial direction, and flows and cools while directly touching the low-pressure side common electrode 24 and the switching element 62S (indicated by arrow F7). Further, the refrigerant flows radially outward in the inverter outward refrigerant path 825 and flows while directly touching the phase inverter output electrodes 63U, 63V, 63W and the switching element 61S to perform cooling (indicated by arrow F8).

  The refrigerant whose temperature has risen through the main body refrigerant path 82 is introduced from the liquid hole 833 through the inlet 861 to the cooling device 86 (shown by an arrow F9), and is cooled inside the cooling device 86. The cooled refrigerant is sucked from the outlet 862 of the cooling device 86 into the suction port 852 of the pressure pump 85 (shown by an arrow F10). Thereby, the refrigerant is circulated. The bus refrigerant path 81 serves as a circulating forward path.

  The cooling structure 8 of the power conversion device 1 according to the first embodiment is configured such that power is supplied to the power conversion unit 4 and the inverter unit 6 that perform power conversion via the first bus bar 71 and the second bus bar 72. The cooling structure 8 of the power conversion apparatus 1 that supplies and cools a refrigerant to the conversion unit 4 and the inverter unit 6, and is disposed on the coaxially outer side of the hollow cylindrical first bus bar 71 and the first bus bar 71. The hollow cylindrical second bus bar 72 is connected to the coaxial outer conductor, and the refrigerant flows through the bus refrigerant path 81 formed between the first bus bar 71 and the second bus bar 72.

  According to this, the refrigerant path which supplies a refrigerant | coolant can be formed using the 1st bus bar 71 and the 2nd bus bar 72 for electric power supply, and at least one part of the exclusive member which forms a refrigerant path can be abbreviate | omitted. Therefore, restrictions on layout design are reduced, and further reduction in size and weight of the power conversion device 1 is realized. In addition, since the first bus bar 71 and the second bus bar 72 are arranged inside and outside the same axis, the electric lines of force do not leak to the outside and the noise is low. In addition, by connecting the first bus bar 71 and the second bus bar 72, the electrical line and the refrigerant path can be connected at the same time, thereby reducing the number of work steps. Further, since the first bus bar 71 on the high pressure side is covered and protected by the second bus bar 72 on the low pressure side, reliability and safety are improved.

  Further, the second bus bar 72 has a housing portion (outer peripheral electrode 23) that is expanded in the radial direction, and a booster portion (converter portion 1CV) that performs electrical boosting in the housing portion, and an inverter portion 6 that drives the AC load 99. And a plurality of switching elements 41S, 42S, 61S, and 62S that perform switching included in any of the boosting unit and the inverter unit 6 are arranged in a state of being arranged in parallel in the axial direction at positions close to the center of the housing unit. doing.

  According to this, since the circuit elements from the input capacitor 2 to the inverter unit 6 may be assembled and connected to the inside of the housing part (outer peripheral electrode 24), the assembly man-hour and the electric connection man-hour are reduced. In addition, since the circuit elements from the input capacitor 2 to the inverter unit 6 are covered and protected by the low voltage side housing (outer peripheral electrode 23), reliability and safety are improved. Furthermore, impedance mismatch is eliminated by the coaxial arrangement of the DC circuit and the rotationally symmetrical arrangement of the three-phase AC circuit.

  Furthermore, the plurality of switching elements 41S, 42S, 61S, 62S are arranged in a state of being separated along the axial direction, and the refrigerant is arranged from the bus refrigerant path 81 to the plurality of switching elements 41S, 42S, in the housing portion (outer peripheral electrode 23). When flowing toward 61S, 62S, cooling is performed by flowing between the switching elements 41S, 42S, 61S, 62S spaced apart in the axial direction in a crank shape. According to this, efficient cooling can be performed using the gaps in the arrangement space in which the switching elements 41S, 42S, 61S, and 62S are arranged at high density.

  Furthermore, the plurality of switching elements 41S, 42S, 61S, 62S are arranged in a state of being separated along the axial direction, and the refrigerant is arranged from the bus refrigerant path 81 to the plurality of switching elements 41S, 42S, in the housing portion (outer peripheral electrode 23). When flowing toward 61S, 62S, the inside of the accommodating portion (outer peripheral electrode 23) is cooled by flowing the switching elements 41S, 42S, 61S, 62S spaced apart in the axial direction while changing the direction inward and outward in the radial direction. Do. According to this, efficient cooling can be performed using the gaps in the arrangement space in which the switching elements 41S, 42S, 61S, and 62S are arranged at high density.

  Next, the difference between the cooling structure 8A of the power conversion device 1A of the second embodiment and the cooling structure 8 of the first embodiment will be mainly described. FIG. 5 is a left half sectional view schematically showing the operation of the cooling structure 8A of the power conversion device 1A of the second embodiment. In the second embodiment, the method for cooling the reactor 3 and the configuration of the return path for circulating the refrigerant are different from those in the first embodiment, and the others are similar to those in the first embodiment.

  In the second embodiment, a second reactor refrigerant path 826 is added to the main body refrigerant path 82A. The second reactor refrigerant path 826 is formed inward in the radial direction between the core 36 of the reactor 3 and the low-pressure side common electrode 24 that are spaced apart by the insulating member 945. An axially-divided refrigerant path having an approximate reference sign that connects the outer circumferences of the reactor refrigerant path 821 and the second reactor refrigerant path 826 is formed. As a result, the refrigerant that has flowed into the reactor 3 of the electric circuit body from the liquid hole 831 of the flange-like connection portion 711 on the high-pressure side is divided into the reactor refrigerant path 821 and the second reactor refrigerant path 826.

  As in the first embodiment, the refrigerant branched into the reactor refrigerant path 821 flows in the reactor refrigerant path 821 inward in the radial direction and flows while directly touching one surface of the core 36 (the upper surface in FIG. 5) for cooling. Perform (shown by arrow F4). Subsequently, the refrigerant flows into the power converter 4 and flows through the power converter inward refrigerant path 822 and the power converter outward refrigerant path 823 (indicated by arrows F5 and F6).

  On the other hand, the refrigerant diverted to the second reactor refrigerant path 826 flows in the second reactor refrigerant path 826 inward in the radial direction, and flows and cools while directly touching the other surface of the core 36 (the lower surface in FIG. 5) ( Arrow F11). Subsequently, the refrigerant joins the outer periphery of the power conversion unit outward refrigerant path 823. Similarly to the first embodiment, the combined refrigerant flows into the inverter unit 6 from the liquid hole 832 and flows through the inverter inward refrigerant path 824 and the inverter outward refrigerant path 825 to reach the liquid hole 833 (arrow F7). F8).

  A central refrigerant path 813 is used as a return path for introducing the refrigerant whose temperature has risen through the main body refrigerant path 82A into the cooling device 86. The central refrigerant path 813 is formed in the hollow interior of the first bus bar 71. Further, as shown in FIG. 5, a return pipe 88 is disposed so as to penetrate the first bus bar 71 and the second bus bar 72 in the radial direction. One end of the return pipe 88 opens to the central refrigerant path 813, and the other end communicates with the inlet 861 of the cooling device 86. In addition, electrical insulation between the first bus bar 71 and the second bus bar 72 and the return pipe 88 is ensured by an insulator (not shown).

  The refrigerant that has flowed out of the liquid hole 833 of the high-voltage side inverter input electrode 53 flows through the central refrigerant path 813 (indicated by arrow F12), and is introduced into the cooling device 86 through the return pipe 88 (indicated by arrow F13). Thereby, the refrigerant is circulated. In addition, the cylindrical bus refrigerant path 811 and the radial bus refrigerant path 812 serve as a forward path for circulation, and the central refrigerant path 813 serves as a return path for circulation.

  Next, the configuration of the connecting portion 7J in which the bus bar set 7 and the external conductor 7X are connected in the axial direction in the second embodiment and the method of connecting work will be described. FIG. 6 is a side cross-sectional view showing a separated state of the connecting portion 7J in the second embodiment. FIG. 7 is a ZZ arrow view of FIG. 6 and shows a cross-sectional shape orthogonal to the central axis CL of the bus bar set 7. FIG. 8 is a side cross-sectional view showing a connected state of the connecting portion 7J.

  The bus bar set 7 is shown on the left side of FIG. 7, and the outer conductor 7X is shown on the right side. The outer conductor 7X includes a first conductor 71X having the same diameter as that of the first bus bar 71 and a second conductor 72X having the same diameter as that of the second bus bar 72 that are coaxially arranged on the center axis CL. The outer peripheral surface of the second bus bar 72 and the second conductor 72X arranged on the coaxial outer side is covered with an insulating coating 78 except for the front end portion to be connected. Insulating support members 79 are interposed between the second bus bar 72 and the first bus bar 71 and between the second conductor 72X and the first conductor 71X at a plurality of locations in the axial direction. As shown in FIG. 7, the insulating support members 79 are divided into three in the circumferential direction and arranged at a pitch of 120 °. The insulation support member 79 ensures insulation performance and reliably forms the cylindrical bus refrigerant path 811.

  The front end portion of the outer conductor 7X connected to the first conductor 71X is an enlarged taper pressure contact portion 731 that is enlarged in a tapered shape. An annular seal groove 761 is formed on the outer peripheral surface near the tip of the second conductor 72X. The bottom surface of the seal groove 761 is smoothly finished, and an O-ring 765 as a seal member is fitted therein. A male screw 771 is engraved on the outer peripheral surface slightly behind the seal groove 761 of the second conductor 72X.

  On the other hand, the front end portion to which the first bus bar 71 of the bus bar set 7 is connected is a reduced taper pressure contact portion 732 that is reduced to a tapered shape. Further, an enlarged diameter enlarged portion 74 is provided at the tip of the second bus bar 72. The inner peripheral surface of the enlarged diameter portion 74 is a smoothly finished seal surface 762. Furthermore, a stepped ring-shaped nut member 75 is fitted on the outer periphery of the enlarged diameter portion 74. The nut member 75 cannot be removed from the enlarged diameter portion 74 and is rotatable around the central axis CL. The nut member 75 is always in contact with the outer periphery of the second bus bar 72 to ensure electrical continuity, and is movable in the axial direction. A female screw 772 is engraved on the inner periphery of the nut member 75 near the tip. The outer peripheral surface of the nut member 75 is covered with an insulating coating 751.

  In the connecting operation, first, the bus bar set 7 and the external conductor 7X are arranged to face each other as shown in FIG. 6, and the both 7 and 7X are gradually brought closer to each other. Then, the male screw 771 of the second conductor 72X and the female screw 772 of the nut member 75 of the second bus bar 72 come into contact with each other, so that the nut member 75 is driven to rotate around the central axis CL. As the nut member 75 is screwed, the enlarged taper pressure contact portion 731 of the first conductor 71X and the reduced taper pressure contact portion 732 of the first bus bar 71 approach each other. Eventually, the reduced taper pressure contact portion 732 enters the pressurization portion 731 and is in pressure contact therewith. At this time, since the operating force required for the rotational drive of the nut member 75 becomes excessive, the rotational drive is discontinued and the connection operation is terminated.

  At the end of the connecting operation, the connecting portion 7J is in the connected state shown in FIG. In the connected state, the inner enlarged taper pressure contact portion 731 and the reduced taper pressure contact portion 732 become a taper pressure contact portion 73 that is in pressure contact with each other, and electrical conduction is ensured. However, since liquid-tightness is not ensured, a slight amount of refrigerant can be transferred between the cylindrical bus refrigerant path 811 and the central refrigerant path 813. In addition, electrical continuity between the outer second conductor 72X and the second bus bar 72 is ensured by the fastening portion 77 to which the male screw 771 and the female screw 772 of the nut member 75 are fastened. Further, the sealing between the second conductor 72X and the second bus bar 72 is ensured by the liquid-tight portion 76 in which the O-ring 765 fitted in the seal groove 761 is pressed against the seal surface 762. Thereby, the leakage of the refrigerant from the cylindrical bus refrigerant path 811 is prevented.

  The cooling structure 8A of the power conversion device 1A of the second embodiment further includes a pressure pump 85 that pumps and circulates the refrigerant, and one of the bus refrigerant path 81 and the central refrigerant path 813 is the forward path and the other is the return path during the refrigerant circulation. It becomes.

  According to this, since heat exchange is performed between the forward path and the return path, the cooling performance is high. Further, since the forward path and the return path can be interchanged and the direction in which the refrigerant flows is not limited, the degree of freedom in design is great. Furthermore, if a refrigerant | coolant is a fluid, any of a liquid phase, a gaseous phase, and mixing of a liquid phase and a gaseous phase may be sufficient, and the freedom degree of a refrigerant | coolant selection is large.

  Further, in the connecting portion 7J that connects the first bus bar 71 and the second bus bar 72 to the outer conductor 7X, the first bus bar 71 has a reduced taper pressure contact portion 732, and the reduced taper pressure contact portion 732 is the first conductor of the outer conductor 7X. The second bus bar 72 is inserted into the enlarged taper pressure contact portion 731 of 71X, a fastening portion (female screw 772) is provided on the radially outer side, and the fastening portion is fastened with the male screw 771 of the second conductor 72X of the outer conductor 7X. The first bus bar 71 and the second bus bar 72 are electrically connected inside and outside the same axis.

  According to this, since the reduced taper pressure contact portion 732 and the enlarged taper pressure contact portion 731 also serve as a guide for connection work, workability is good. Further, since the reduced taper pressure contact portion 732 and the enlarged taper pressure contact portion 731 can increase the contact surface pressure due to the wedge effect, the contact resistance is reduced. Furthermore, since a slight leakage of the inner refrigerant is allowed if the outer seal structure is secured, a simple structure can be employed to contribute to cost reduction.

  In addition, as a cooling structure of the reactor 3, it is also possible to employ a structure that guides the refrigerant from the gap of the core 36 to the coil 35. In addition, since the power converters 1 and 1A are less dependent on natural cooling, the installation direction is not restricted, and the central axis CL may be arranged in either the horizontal direction or the vertical direction. Furthermore, in the connecting portion 7J of the second embodiment, the structures of the bus bar set 7 and the external conductor 7X may be interchanged. That is, the enlarged taper pressure contact portion 731, the seal groove 761, and the male screw 771 may be provided on the bus bar set 7 side. The present invention can have various other applications and modifications.

1, 1A: Power converter 1CV: Converter unit (boost unit)
2: Input capacitor 23: Peripheral electrode (accommodating part) 3: Reactor 4: Power conversion part 41S, 42S: Switching element 5: Output capacitor 6: Inverter part 61S, 62S: Switching element 7: Bus bar set 71: First bus bar 72 : Second bus bar 7J: connecting portion 7X: outer conductor 73: taper pressure contact portion 731: enlarged taper pressure contact portion 732: reduced taper pressure contact portion 77: fastening portion 771: male screw 772: female screw 8, 8A: cooling structure of power converter 81 : Bus refrigerant path 813: Central refrigerant path 82, 82A: Main body refrigerant path 85: Pressure feed pump CL: Center axis

Claims (6)

The cooling structure of the power conversion device is configured such that power is supplied to the power conversion unit that performs power conversion via the first bus bar and the second bus bar, and cooling is performed by supplying a refrigerant to the power conversion unit. And
The hollow cylindrical first bus bar and the hollow cylindrical second bus bar disposed on the coaxial outer side of the first bus bar are connected to the coaxial outer conductor,
A cooling structure for a power converter, in which the refrigerant flows in at least one of a bus refrigerant path formed between the first bus bar and the second bus bar and a central refrigerant path formed in a hollow interior of the first bus bar.   The cooling structure for a power converter according to claim 1, further comprising a pressure pump for pumping and circulating the refrigerant, wherein one of the bus refrigerant path and the central refrigerant path is an outward path and the other is a return path when the refrigerant is circulated. In the connecting portion that connects the first bus bar and the second bus bar to the outer conductor,
The first bus bar has a reduced taper pressure contact portion, and the reduced taper pressure contact portion is inserted into the enlarged taper pressure contact portion of the outer conductor,
The second bus bar is provided with a fastening portion on a radially outer side, and the fastening portion is fastened with the outer conductor,
The cooling structure for a power conversion device according to claim 1 or 2, wherein the first bus bar and the second bus bar are electrically connected inside and outside the same axis. The second bus bar has an accommodating portion expanded in a radial direction,
Provided in the housing portion is a boosting portion that performs electrical boosting and an inverter portion that drives an AC load, and includes a plurality of switching elements that perform switching in either the boosting portion or the inverter portion in the center of the housing portion. The cooling structure for a power conversion device according to any one of claims 1 to 3, wherein the cooling structure is arranged in a state of being spaced apart from each other in the axial direction and arranged in parallel at a position close to. The plurality of switching elements are arranged in a state of being separated along the axial direction,
The power conversion device according to claim 4, wherein when the refrigerant flows from the bus refrigerant path toward the plurality of switching elements in the housing portion, cooling is performed by flowing the switching elements spaced apart in the axial direction in a crank shape. Cooling structure. The plurality of switching elements are arranged in a state of being separated along the axial direction,
When flowing the refrigerant from the bus refrigerant path toward the plurality of switching elements in the accommodating portion, the refrigerant flows between the switching elements separated in the axial direction while changing the direction inward and outward in the radial direction. The cooling structure for a power converter according to claim 4, wherein cooling is performed.

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