Electric compressor

Abstract

To provide an electric compressor capable of making uniform a loss / heat generation of a switching element and meeting the need to widen a range without increasing a size.SOLUTION: An electric compressor 1 comprises: an inverter 16 that includes a plurality of switching elements 18A-18F and supplies power to a motor 8; a housing 2 including a motor chamber 4 in which the motor is installed and an inverter storage 6 to which the inverter is fitted; a partition wall 3 for the motor chamber and the inverter storage; and a plurality of connection terminals 10A, 10B electrically connected at one end to the motor and provided to project from the motor toward the partition wall. The connection terminals are provided to be dispersed, and electrically connected at the other end through the partition wall to the inverter. The switching elements are provided in the partition wall to be dispersed respectively corresponding to the connection terminals.SELECTED DRAWING: Figure 1

Description

Technical Field

[0005]

[0001] The present invention relates to an electric compressor including an inverter that has a plurality of switching elements and supplies power to a motor.

Background Art

Prior Art Documents

Patent Documents

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0006] Furthermore, in recent years, there has been progress in widening the voltage range of this type of electric compressor. For example, inverters have been developed that widen the voltage range by opposing the neutral points of the motors with a half-bridge instead of bundling them together (see, for example, Patent Document 2). In that case, 12 switching elements must be placed on the partition wall of the housing, but with the conventional structure in which hermetic pins are attached to a hermetic plate, there is no flexibility in the placement of the switching elements, and the number of hermetic pins also increases, so considering the dielectric strength and cooling efficiency, it becomes difficult to place all of them on the partition wall without increasing the dimensions of the housing, and improvement has been desired.

[0007] On the other hand, an electric compressor has also been proposed in which three energizing pins (connection terminals) protrude from the motor and are passed through the bulkhead of the housing to connect to an inverter (see, for example, Patent Document 3).

[0008] The present invention was made to solve the aforementioned conventional technical problems, and aims to provide an electric compressor that can equalize the loss / heat generation of the switching element and furthermore, can accommodate a wide range without increasing the dimensions. [Means for solving the problem]

[0009] The electric compressor of the present invention is equipped with an inverter that supplies power to a motor having a plurality of switching elements, and comprises a housing comprising a motor chamber in which the motor is housed and an inverter housing in which the inverter is mounted, a partition wall between the motor chamber and the inverter housing, and a component provided with one end electrically connected to the motor and protruding from the motor toward the partition wall. 6 It is equipped with connection terminals, each connection terminal is provided at a distance, and the other end is electrically connected to the inverter by passing through the partition wall. The inverter has seven switching elements and one diode, and the switching elements and diode are, It is characterized by being provided in a distributed manner on the partition wall, corresponding to each connection terminal.

[0010] Second The electric compressor of the invention is characterized in that, in the above invention, the switching element is located near each connection terminal and provided in the partition wall. 。 [Effects of the Invention]

[0011] According to the present invention, in an electric compressor equipped with an inverter that supplies power to a motor having a plurality of switching elements, the present invention comprises a housing comprising a motor chamber in which the motor is built in and an inverter housing in which the inverter is mounted, a partition wall between the motor chamber and the inverter housing, and a component provided with one end electrically connected to the motor and protruding from the motor toward the partition wall. 6 It is equipped with connection terminals, with each connection terminal provided at a distance, and the other end, which penetrates the partition wall, is electrically connected to the inverter. The inverter has seven switching elements and one diode, and the switching elements and diode are connected. By distributing the components across the partition wall to correspond to each connection terminal, the wiring lengths to each phase of the motor can be made equal or nearly equal, thereby equalizing the surge voltage in each phase and uniformizing the loss / heat generation of each switching element.

[0012] In addition, since the degree of freedom in the arrangement of the switching elements increases, even when the number of connection terminals and switching elements increases, it becomes possible to arrange them while satisfying the withstand voltage and cooling efficiency without increasing the dimensions of the housing. As a result, it becomes possible to smoothly cope with the widening of the voltage range.

[0013] In this case, Second If the switching elements are provided on the partition walls in the vicinity of the respective connection terminals as in the invention, the wiring length from the switching elements to the connection terminals can be shortened to reduce the surge voltage. 。

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic longitudinal sectional view of an electric compressor of an embodiment to which the present invention is applied. [Figure 2] It is an electric circuit diagram of an embodiment of the electric compressor of FIG. 1 (Example 1). [Figure 3] It is a plan view excluding the cover and the substrate when the electric compressor of the embodiment of FIG. 2 is viewed from the side of the inverter housing portion. [Figure 4] It is a diagram for explaining the operation of the inverter of the embodiment of FIG. 2. [Figure 5] It is an electric circuit diagram of another embodiment of the electric compressor of FIG. 1 (Example 2). [Figure 6] It is a plan view excluding the cover and the substrate when the electric compressor of the embodiment of FIG. 5 is viewed from the side of the inverter housing portion. [Figure 7] It is a diagram for explaining the operation of the inverter of the embodiment of FIG. 5. [Figure 8] It is an electric circuit diagram of still another embodiment of the electric compressor of FIG. 1 (Example 3). [Figure 9] It is a plan view excluding the cover and the substrate when the electric compressor of the embodiment of FIG. 8 is viewed from the side of the inverter housing portion. [Figure 10] It is a diagram for explaining the operation of the inverter of the embodiment of FIG. 8. [Figure 11] It is an electric circuit diagram of still another embodiment of the electric compressor of FIG. 1 (Example 4). [Figure 12] It is a plan view excluding the cover and substrate, as seen from the side of the inverter housing portion, of the electric compressor of the embodiment of FIG. 11. [Figure 13] It is a diagram for explaining the operation of the inverter of the embodiment of FIG. 11.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Example

[0016] First, an electric compressor (inverter-integrated electric compressor) 1 of an embodiment to which the present invention is applied will be described using FIGS. 1 to 4. Note that the electric compressor 1 of the embodiment constitutes a part of the refrigerant circuit of a vehicle air conditioner mounted on an electric vehicle.

[0017] (1) Structure of the electric compressor 1 In FIG. 1, inside a metal (aluminum in the embodiment) housing 2 (heat sink) of the electric compressor 1, a motor chamber 4 and an inverter housing portion 6 are partitioned by a partition wall 3 (a part of the housing 2) that intersects the axial direction of the housing 2. Inside the motor chamber 4, for example, a scroll-type compression mechanism 7 and a motor 8 (electric motor) for driving this compression mechanism 7 are accommodated. In the case of the embodiment, the motor 8 is an IPMSM (Interior Permanent Magnet Synchronous Motor) composed of a stator 9 fixed to the housing 2 and a rotor 11 that rotates inside this stator 9.

[0018] A bearing section 12 is formed in the center of the bulkhead 3 on the motor chamber 4 side. One end of the drive shaft 13 of the rotor 11 is supported by this bearing section 12, and the other end of the drive shaft 13 is connected to the compression mechanism 7. An intake port 14 is formed near the bulkhead 3 at the position corresponding to the motor chamber 4 of the housing 2. When the rotor 11 (drive shaft 13) of the motor 8 rotates and the compression mechanism 7 is driven, a low-temperature refrigerant, which is the working fluid, flows into the motor chamber 4 of the housing 2 from this intake port 14, is drawn into the compression mechanism 7, and is compressed.

[0019] The refrigerant, compressed by the compression mechanism 7 and becoming high temperature and pressure, is then discharged from a discharge port (not shown) to the refrigerant circuit outside the housing 2. In addition, the low-temperature refrigerant flowing in from the intake port 14 passes near the partition wall 3, around the motor 8, and is drawn into the compression mechanism 7, thus cooling the partition wall 3 as well.

[0020] In this embodiment, a busbar 5 is attached to the coil end of the stator 9 on the bulkhead 3 side. This busbar 5 is annular in shape and is electrically connected to the coils 9U, 9V, and 9W (Figure 2) of each phase (UVW) wound around the stator 9 of the motor 8. In this embodiment, three connection terminals 10A, 10B, and 10C are attached to the busbar 5 and are provided protruding in the direction of the bulkhead 3. One end of each connection terminal 10A, 10B, and 10C is electrically connected to the coils 9U, 9V, and 9W of each phase of the motor 8 via the busbar 5.

[0021] In this embodiment, the connection terminals 10A, 10B, and 10C are provided at equal intervals (120° intervals around the axis of the housing 2) in the circumferential direction of the motor 8. Through holes 15 are formed in the partition wall 3 at positions corresponding to each connection terminal 10A, 10B, and 10C (three locations). Each connection terminal 10A, 10B, and 10C passes through each through hole 15, i.e., penetrates the partition wall 3, and its other end enters the inverter housing 6. This state is shown in Figure 3. Note that the spaces between each through hole 15 and each connection terminal 10A, 10B, and 10C are insulated and sealed with O-rings or the like (not shown).

[0022] (2) Structure of inverter 16 The inverter housing 6, which is separated from the motor room 4 by the partition wall 3, houses the inverter 16 that drives and controls the motor 8. In this embodiment, the inverter 16 consists of a substrate 17, six upper and lower arm switching elements 18A to 18F located on one side of the substrate 17 (the side facing the partition wall 3) and wired to the substrate 17, a control unit 21 wired on the other side of the substrate 17, and HV connectors, LV connectors, etc. (not shown). In this embodiment, each switching element 18A to 18F is composed of an insulated gate bipolar transistor (IGBT) with a MOS structure incorporated into its gate portion.

[0023] The other ends of each connection terminal 10A, 10B, and 10C that enter the inverter housing 6 from the partition wall 3 are electrically connected to the circuit board 17 of the inverter 16 via press-fit terminals or the like (not shown). In this embodiment, as shown in Figure 3, the upper arm switching element 18A and the lower arm switching element 18D, which constitute the U-phase half-bridge circuit 19U of the three-phase inverter circuit (three-phase inverter circuit) 28 described later, are located near the left and right of the connection terminal 10A and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0024] Furthermore, the upper arm switching element 18B and the lower arm switching element 18E, which constitute the V-phase half-bridge circuit 19V of the inverter circuit 28, are located near the left and right of the connection terminal 10B and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. In addition, the upper arm switching element 18C and the lower arm switching element 18F, which constitute the W-phase half-bridge circuit 19W of the inverter circuit 28, are located near the left and right of the connection terminal 10C and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0025] In this embodiment, two switching elements 18A to 18F are distributed and arranged in a manner corresponding to each of the connection terminals 10A to 10C, and are provided on the partition wall 3. Furthermore, the terminal portions 22 of each switching element 18A to 18F are positioned on the substrate 17 side with the respective connection terminals 10A to 10C facing outwards, and are electrically connected to the substrate 17 of the inverter 16. In this manner, the inverter 16 having the inverter circuit 28 is configured to supply power to the motor 8 via the connection terminals 10A to 10C and the busbar 5.

[0026] Furthermore, each switching element 18A to 18F is in close contact with the partition wall 3 via an insulating and / or heat-dissipating sheet (not shown), and is in a heat exchange relationship with the partition wall 3 of the housing 2. At this time, each switching element 18A to 18F is positioned to avoid the areas corresponding to the bearing 12 and the drive shaft 13. As mentioned above, the partition wall 3 is cooled by the refrigerant drawn into the motor chamber 4, so each switching element 18A to 18F is in a heat exchange relationship with the drawn refrigerant via the partition wall 3, is cooled by the refrigerant drawn into the motor chamber 4 via the partition wall 3, and each switching element 18A to 18F itself dissipates heat to the refrigerant via the partition wall 3. In other words, the partition wall 3 of the electric compressor 1 (part of the housing 2) becomes a heat sink for each switching element 18A to 18F.

[0027] (3) Circuit configuration of inverter 16 Next, in Figure 2, the inverter 16 comprises the aforementioned three-phase inverter circuit 28 and a control unit 21. The inverter circuit 28 is a circuit that converts the DC voltage (for example, DC300V) of the DC power supply (battery of the electric vehicle) 29 into a three-phase AC voltage and applies it to the coils 9U, 9V, and 9W of the stator 9 of the motor 8. In this embodiment, the coils 9U, 9V, and 9W of the stator 9 of the motor 8 are bundled at the neutral point.

[0028] The inverter circuit 28 has the aforementioned U-phase half-bridge circuit 19U, V-phase half-bridge circuit 19V, and W-phase half-bridge circuit 19W. Each of the phase half-bridge circuits 19U to 19W has the aforementioned upper arm switching elements 18A to 18C and lower arm switching elements 18D to 18F, respectively. Furthermore, each of the switching elements 18A to 18F incorporates a flywheel diode connected in antiparallel.

[0029] The collector electrodes of the upper arm switching elements 18A to 18C of the inverter circuit 28 are connected to the positive power supply line 31 (HV+) of the DC power supply 29. On the other hand, the emitter electrodes of the lower arm switching elements 18D to 18F of the inverter circuit 28 are connected to the negative power supply line 32 (HV-) of the DC power supply 29.

[0030] Furthermore, the emitter electrode of the upper arm switching element 18A of the U-phase half-bridge circuit 19U is connected to the collector electrode of the lower arm switching element 18D, and their connection point (arm midpoint) is connected to one end of the U-phase coil 9U of the motor 8. In addition, the emitter electrode of the upper arm switching element 18B of the V-phase half-bridge circuit 19V is connected to the collector electrode of the lower arm switching element 18E, and their connection point (arm midpoint) is connected to one end of the V-phase coil 9V of the motor 8. Moreover, the emitter electrode of the upper arm switching element 18C of the W-phase half-bridge circuit 19W is connected to the collector electrode of the lower arm switching element 18F, and their connection point (arm midpoint) is connected to one end of the W-phase coil 9W of the motor 8. The other ends of each coil 9U to 9W are bundled together and serve as the neutral point as described above.

[0031] The aforementioned connection terminal 10A constitutes part of the wiring 33U between the connection point of the upper arm switching element 18A and lower arm switching element 18D of the U-phase half-bridge circuit 19U and the U-phase coil 9U of the motor 8. Furthermore, connection terminal 10B constitutes part of the wiring 33V between the connection point of the upper arm switching element 18B and lower arm switching element 18E of the V-phase half-bridge circuit 19V and the V-phase coil 9V of the motor 8. Additionally, connection terminal 10C constitutes part of the wiring 33W between the connection point of the upper arm switching element 18C and lower arm switching element 18F of the W-phase half-bridge circuit 19W and the W-phase coil 9W of the motor 8.

[0032] Next, Figure 4 shows an example of the control operation of the control unit 21 of the inverter 16 in this embodiment. In this figure, cu, cv, and cw are normalized pulse width command values, and vu, vv, and vw are the voltages applied to the UVW phases of the motor 8, respectively. Also, Iu, Iv, and Iw are examples of currents flowing through the motor 8.

[0033] The control unit 21 switches (ON / OFF) the switching elements 18A to 18F of the half-bridge circuits 19U, 19V, and 19W for each phase of the inverter circuit 28, thereby applying the three-phase AC voltages vu, vv, and vw to the respective coils 9U, 9V, and 9W of the motor 8. In Figure 4, the voltages are normalized so that "1" is applied when the upper arm switching elements 18A to 18C are ON, and "-1" is applied when the lower arm switching elements 18D to 18F are ON. Also, vu, vv, and vw are shown as values ​​obtained by subtracting the neutral point potential vmid of the motor 8 from the output voltage of the inverter circuit 16.

[0034] As shown in Figure 4, the motor 8 is driven to rotate by the inverter 16 applying a three-phase AC voltage to it. In this invention, as described above, three connection terminals 10A to 10C are provided in a distributed manner, protruding from the motor 8 in the direction of the partition wall 3, and the other end that penetrates the partition wall 3 is electrically connected to the inverter 16. Switching elements 18A to 18F are also provided in a distributed manner on the partition wall 3, corresponding to each connection terminal 10A to 10C. This makes it possible to make the lengths of the wiring 33U to 33W to each phase of the motor 8 equal or close to equal. As a result, the surge voltage in each phase U, V, and W is made equal, and the loss / heat generation of each switching element 18A to 18F is made uniform.

[0035] Furthermore, in this embodiment, two switching elements 18A to 18F are provided in each of the connection terminals 10A to 10C, and are located near them on the partition wall 3. This shortens the wiring length from switching elements 18A and 18D to connection terminal 10A, from switching elements 18B and 18E to connection terminal 10B, and from switching elements 18C and 18F to connection terminal 10C, thereby further reducing surge voltage.

[0036] Furthermore, in this embodiment, since each connection terminal 10A to 10C is provided at equal intervals in the circumferential direction of the motor 8, it becomes possible to smoothly equalize the wiring length (length of wiring 33U to 33W) to each of the UVW phases of the motor 8. [Examples]

[0037] Next, other embodiments of the present invention will be described with reference to Figures 5 to 7. The structure of the target electric compressor 1 is the same as in Figure 1, and components indicated by the same reference numerals as in Figures 1 to 4 perform the same or similar functions. The inverter 16 in this embodiment is a 4-wire inverter, and the inverter circuit 28 includes two switching elements 18G and 18H that constitute a fourth half-bridge circuit 19M, in addition to the six switching elements 18A to 18F of the previously described embodiment (Embodiment 1) (Figure 5).

[0038] In other words, the inverter circuit 28 of the inverter 16 in this embodiment is composed of a total of eight switching elements 18A to 18H. In this case, the collector electrode of the upper arm switching element 18G of the fourth half-bridge circuit 19M is connected to the positive power supply line 31, and the emitter electrode of the lower arm switching element 18H is connected to the negative power supply line 32.

[0039] Then, the emitter electrode of the upper arm switching element 18G of the half-bridge circuit 19M and the collector electrode of the lower arm switching element 18H are connected, and their connection point (arm midpoint) is connected to the neutral point of the motor 8 via the excitation coil 34.

[0040] As described above, the inverter 16 in this embodiment has eight switching elements 18A to 18H, so in addition to the three connection terminals 10A to 10C mentioned above, another connection terminal 10D is provided. This connection terminal 10D is also attached to the bus bar 5, and one end of it is electrically connected to the neutral point of the motor 8 via the bus bar 5. Furthermore, the connection terminal 10D also protrudes from the bus bar 5, passes through the same insertion hole 15 in the partition wall 3 (penetrating the partition wall 3), and is electrically connected to the circuit board 17 of the inverter 16 via a press-fit terminal or the like, as described above.

[0041] In this embodiment, the connection terminal 10D forms part of the wiring 33M between the connection point of the upper arm switching element 18G and the lower arm switching element 18H of the fourth half-bridge circuit 19M and the neutral point of the motor 8.

[0042] In this embodiment, the connection terminals 10A, 10B, 10D, and 10C are provided at equal intervals in the circumferential direction of the motor 8 (at intervals of 90° around the axis of the housing 2) (Figure 6). In this embodiment as well, as shown in Figure 6, the upper arm switching element 18A and the lower arm switching element 18D of the U-phase half-bridge circuit 19U are located near the left and right connections of the connection terminal 10A and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0043] Furthermore, the upper arm switching element 18B and lower arm switching element 18E of the V-phase half-bridge circuit 19V of the inverter circuit 28 are located near the left and right of the connection terminal 10B and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. In addition, the upper arm switching element 18C and lower arm switching element 18F of the W-phase half-bridge circuit 19W of the inverter circuit 28 are located near the left and right of the connection terminal 10C and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0044] Furthermore, the upper arm switching element 18G and lower arm switching element 18H of the fourth half-bridge circuit 19M of the inverter circuit 28 are located near the left and right sides of the connection terminal 10D and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. Thus, in this embodiment as well, each switching element 18A to 18H is distributed in pairs, corresponding to each of the connection terminals 10A to 10D, and is provided on the partition wall 3. In addition, the terminal portions 22 of each switching element 18A to 18H are positioned facing the respective connection terminals 10A to 10D and stand upright on the substrate 17 side, and are electrically connected to the substrate 17 of the inverter 16.

[0045] In this embodiment as well, the inverter 16 having the inverter circuit 28 is configured to supply power to the motor 8 via connection terminals 10A to 10D and busbar 5. Furthermore, each switching element 18G and 18H is in close contact with the partition wall 3 via insulating and / or heat dissipation sheets, and is in a heat exchange relationship with the partition wall 3 of the housing 2. It is cooled by the refrigerant drawn into the motor chamber 4 through the partition wall 3, and each switching element 18G and 18H itself dissipates heat to the refrigerant through the partition wall 3. The rest is the same as in the embodiment described above.

[0046] Next, Figure 7 shows an example of the control operation of the control unit 21 of the inverter 16 in this embodiment. In this figure, cu, cv, and cw are normalized pulse width command values, and vu, vv, and vw are the voltages applied to the UVW phases of the motor 8, respectively. Also, vmid is the neutral point voltage of the motor 8. Furthermore, Iu, Iv, and Iw are examples of currents flowing through the motor 8.

[0047] In this case as well, the control unit 21 applies the three-phase AC voltages vu, vv, and vw to the respective coils 9U, 9V, and 9W of the motor 8 by switching (ON / OFF) the switching elements 18A to 18F of the half-bridge circuits 19U, 19V, and 19W of each phase of the inverter circuit 28. The fourth half-bridge circuit 19M keeps the lower arm switching element 18H constantly ON. Furthermore, the pulse width command values ​​cu, cv, and cw are all changed to PWM command values ​​so that the ON time of the upper arm switching elements 18A to 18C is increased.

[0048] In this embodiment, a DC current Imid can be passed through the excitation coil 34. By passing current through this excitation coil 34, a strengthening or weakening effect can be applied, enabling efficient driving in high-speed and low-speed regions. The direction of the current is as shown in the electrical circuit diagram in Figure 5, and the currents are directed so that their sum equals zero.

[0049] In this embodiment as well, the four connection terminals 10A to 10D that protrude from the motor 8 toward the partition wall 3 are provided in a distributed manner, and the switching elements 18A to 18H are provided in a distributed manner on the partition wall 3 corresponding to each connection terminal 10A to 10D. This makes it possible to make the lengths (wiring lengths) of the wiring 33U to 33W and 33M to each phase and neutral point of the motor 8 equal or close to equal. As a result, the surge voltages in the wiring to each phase U, V, W and the neutral point are made equal, and the losses / heat generation of each switching element 18A to 18H is made uniform.

[0050] Furthermore, in this embodiment as well, two switching elements 18A to 18H are provided in each of the connection terminals 10A to 10D, and are located near them on the partition wall 3. This shortens the wiring length from switching elements 18A and 18D to connection terminal 10A, from switching elements 18B and 18E to connection terminal 10B, from switching elements 18C and 18F to connection terminal 10C, and from switching elements 18G and 18H to connection terminal 10D, thereby further reducing surge voltage.

[0051] Furthermore, in this embodiment as well, since the connection terminals 10A, 10B, 10D, and 10C are distributed at equal intervals in the circumferential direction of the motor 8, it becomes possible to smoothly equalize the wiring length (length of wiring 33U~33W, 33M) to each of the UVW phases and the neutral point of the motor 8.

[0052] Furthermore, because the arrangement of switching elements 18A to 18H is more flexible, even if the number of connection terminals increases to four (10A to 10D) and the number of switching elements increases to eight (18A to 18H), it becomes possible to arrange them while satisfying the insulation withstand voltage and cooling efficiency requirements without increasing the dimensions of housing 2. [Examples]

[0053] Next, another embodiment of the present invention will be described with reference to Figures 8 to 10. The structure of the target electric compressor 1 is the same as in Figure 1, and components indicated by the same reference numerals as in Figures 1 to 7 perform the same or similar functions. The inverter 16 in this embodiment is also a 4-wire inverter, but the inverter circuit 28 differs from the previously described embodiment (Embodiment 2) in that it is configured to have only a lower arm switching element 18H, which is connected from the neutral point of the motor 8 through the diode 36 and the excitation coil 34.

[0054] In other words, in this example, in addition to the six switching elements 18A to 18F, there is another switching element 18H and a diode 36 (Figure 8). That is, the inverter circuit 28 of the inverter 16 in this embodiment is composed of a total of seven switching elements 18A to 18F and 18H, and is further equipped with a diode 36. In this case, the collector electrode of the seventh switching element 18H is connected to the excitation coil 34, and the emitter electrode is connected to the negative power supply line 32. The excitation coil 34 is then connected to the neutral point of the motor 8 via the diode 36. Note that the diode 36 is oriented in the forward direction of the excitation coil 34.

[0055] As described above, the inverter 16 in this embodiment has seven switching elements 18A to 18F, 18H and a diode 36. Therefore, in addition to the three connection terminals 10A to 10C mentioned above, three connection terminals 10D, 10E, and 10F are also provided. Each of the connection terminals 10D to 10F is attached to the bus bar 5, and one end of each is electrically connected to the motor 8 via the bus bar 5. Furthermore, the connection terminals 10D to 10F protrude from the bus bar 5, pass through the same insertion holes 15 in the partition wall 3 (penetrating the partition wall 3), and are electrically connected to the circuit board 17 of the inverter 16 via press-fit terminals or the like, as described above.

[0056] In this embodiment, the connection terminal 10D forms part of the wiring 33M between the collector electrode of the lower arm switching element 18H and the excitation coil 34, the connection terminal 10E forms part of the wiring 33D1 between the excitation coil 34 and the diode 36, and the connection terminal 10F forms part of the wiring 33D2 between the diode 36 and the neutral point of the motor 8.

[0057] In this embodiment, the connection terminals 10A, 10B, 10F, 10E, 10D, and 10C are distributed in the circumferential direction of the motor 8 (Figure 9). In this embodiment as well, as shown in Figure 9, the upper arm switching element 18A and the lower arm switching element 18D of the U-phase half-bridge circuit 19U are located near the left and right sides of the connection terminal 10A and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0058] Furthermore, the upper arm switching element 18B and lower arm switching element 18E of the V-phase half-bridge circuit 19V of the inverter circuit 28 are located near the left and right of the connection terminal 10B and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. In addition, the upper arm switching element 18C and lower arm switching element 18F of the W-phase half-bridge circuit 19W of the inverter circuit 28 are located near the left and right of the connection terminal 10C and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0059] Furthermore, the seventh lower arm switching element 18H of the inverter circuit 28 is located near the connection terminal 10D and is positioned on the side of the partition wall 3 facing the inverter housing 6 in a heat exchange relationship. Also, the diode 36 is located between the connection terminals 10E and 10F and near them, and is positioned on the side of the partition wall 3 facing the inverter housing 6 in a heat exchange relationship.

[0060] Thus, in this embodiment as well, each switching element 18A to 18F is distributed in pairs, corresponding to each of the connection terminals 10A to 10C, and is provided on the partition wall 3. Furthermore, the terminal portions 22 of each switching element 18A to 18F and 18H and the terminal 37 of the diode 36 are positioned on the substrate 17 side with the respective connection terminals 10A to 10F facing upwards, and the inverter 16 is electrically connected to the substrate 17.

[0061] In this embodiment as well, the inverter 16 having the inverter circuit 28 is configured to supply power to the motor 8 via connection terminals 10A to 10F and busbar 5. The switching element 18H and diode 36 are also in close contact with the partition wall 3 via insulating and / or heat dissipation sheets, and are in a heat exchange relationship with the partition wall 3 of the housing 2. They are cooled by the refrigerant drawn into the motor chamber 4 through the partition wall 3, and the switching element 18H and diode 36 themselves dissipate heat to the refrigerant through the partition wall 3. The rest is the same as in the embodiment described above.

[0062] Next, Figure 10 shows an example of the control operation of the control unit 21 of the inverter 16 in this embodiment. In this figure, cu, cv, and cw are normalized pulse width command values, and vu, vv, and vw are the voltages applied to the UVW phases of the motor 8, respectively. Also, vmid is the neutral point voltage of the motor 8. Furthermore, Iu, Iv, and Iw are examples of currents flowing through the motor 8.

[0063] In this case as well, the control unit 21 applies the three-phase AC voltages vu, vv, and vw to the coils 9U, 9V, and 9W of the motor 8 by switching (ON / OFF) the switching elements 18A to 18F of the half-bridge circuits 19U, 19V, and 19W of each phase of the inverter circuit 28. On the other hand, the lower arm switching element 18H, which passes through the excitation coil 34, is kept ON at all times. Also, if the current of the motor 8 is defined as the direction of inflow, a negative current flows as the DC current Imid. Everything else is the same as in the case of Embodiment 2 described above.

[0064] In this embodiment as well, the six connection terminals 10A to 10F that protrude from the motor 8 in the direction of the partition wall 3 are provided in a distributed manner, and the switching elements 18A to 18F, 18H and the diode 36 are provided in a distributed manner on the partition wall 3 corresponding to each connection terminal 10A to 10F. As a result, the lengths (wiring lengths) of the wiring 33U to 33W, 33M, 33D1, and 33D2 to each phase and neutral point of the motor 8 can be made equal or close to equal. This makes it possible to equalize the surge voltage in the wiring to each phase U, V, W and the neutral point, and to equalize the loss / heat generation of each switching element 18A to 18F, 18H and the diode 36.

[0065] Furthermore, in this embodiment, two switching elements 18A to 18F are provided in the partition wall 3, corresponding to each of the connection terminals 10A to 10C, and positioned near them. Additionally, switching element 18H is provided in the partition wall 3, corresponding to connection terminal 10D, and diode 36 is provided in the partition wall 3, corresponding to connection terminals 10E and 10F. As a result, the wiring lengths from switching elements 18A and 18D to connection terminal 10A, from switching elements 18B and 18E to connection terminal 10B, from switching elements 18C and 18F to connection terminal 10C, from switching element 18H to connection terminal 10D, and from diode 36 to connection terminals 10E and 10F are shortened, further reducing surge voltage.

[0066] Furthermore, because the arrangement of switching elements 18A~18F, 18H, and diode 36 is more flexible, even if the number of connection terminals becomes 6 (10A~10F), the number of switching elements increases to 7 (18A~18F, 18H), and diode 36 is added, it is possible to arrange them while satisfying the insulation withstand voltage and cooling efficiency without increasing the dimensions of housing 2. [Examples]

[0067] Next, another embodiment of the present invention will be described with reference to Figures 11 to 13. The structure of the target electric compressor 1 is the same as in Figure 1, and components indicated by the same reference numerals as in Figures 1 to 10 perform the same or similar functions. The inverter 16 in this embodiment is a 6-wire inverter, and the inverter circuit 28 has three additional half-bridge circuits 19U1, 19V1, and 19W1 corresponding to each of the UVW phases, in addition to the half-bridge circuits 19U to 19W (Figure 11). The neutral points of each phase of the motor 8 are not bundled together, and each half-bridge circuit 19U to 19W and each half-bridge circuit 19U1 to 19W1 are opposed to each other with the coils 9U to 9W of the motor 8 in between.

[0068] In this case, each phase half-bridge circuit 19U1 to 19W1 also has its own upper arm switching elements 18A1 to 18C1 and lower arm switching elements 18D1 to 18F1. Each switching element 18A1 to 18F1 also incorporates a flywheel diode connected in antiparallel. The collector electrodes of the upper arm switching elements 18A1 to 18C1 are connected to the positive power supply line 31 of the DC power supply 29. On the other hand, the emitter electrodes of the lower arm switching elements 18D1 to 18F1 are connected to the negative power supply line 32 of the DC power supply 29.

[0069] Furthermore, the emitter electrode of the upper arm switching element 18A1 of the U-phase half-bridge circuit 19U1 and the collector electrode of the lower arm switching element 18D1 are connected, and their connection point (arm midpoint) is connected to the other end of the U-phase coil 9U of the motor 8. In addition, the emitter electrode of the upper arm switching element 18B1 of the V-phase half-bridge circuit 19V1 and the collector electrode of the lower arm switching element 18E1 are connected, and their connection point (arm midpoint) is connected to the other end of the V-phase coil 9V of the motor 8. Moreover, the emitter electrode of the upper arm switching element 18C1 of the W-phase half-bridge circuit 19W1 and the collector electrode of the lower arm switching element 18F1 are connected, and their connection point (arm midpoint) is connected to the other end of the W-phase coil 9W of the motor 8.

[0070] As described above, the inverter 16 in this embodiment has a total of 12 switching elements 18A to 18F and 18A1 to 18F1. Therefore, in addition to the three connection terminals 10A to 10C mentioned earlier, three more connection terminals 10D to 10F are provided (a total of 6). These connection terminals 10D to 10F are also attached to the bus bar 5, and one end of each is electrically connected to the motor 8 via the bus bar 5. Furthermore, the connection terminals 10D to 10F protrude from the bus bar 5, pass through the same insertion holes 15 in the partition wall 3 (penetrating the partition wall 3), and are electrically connected to the circuit board 17 of the inverter 16 via press-fit terminals or the like, as described above.

[0071] In this embodiment, connection terminal 10D constitutes part of the wiring 33U1 between the connection point of the upper arm switching element 18A1 and the lower arm switching element 18D1 of the half-bridge circuit 19U1 and the other end of the U-phase coil 9U of the motor 8. Also, connection terminal 10E constitutes part of the wiring 33V1 between the connection point of the upper arm switching element 18B1 and the lower arm switching element 18E1 of the half-bridge circuit 19V1 and the other end of the V-phase coil 9V of the motor 8. Furthermore, connection terminal 10F constitutes part of the wiring 33W1 between the connection point of the upper arm switching element 18C1 and the lower arm switching element 18F1 of the half-bridge circuit 19W1 and the other end of the W-phase coil 9W of the motor 8.

[0072] In this embodiment, the connection terminals 10A to 10F are provided at equal intervals in the circumferential direction of the motor 8 (at intervals of 60° around the axis of the housing 2) (Figure 12). In this embodiment as well, as shown in Figure 12, the upper arm switching element 18A and the lower arm switching element 18D of the U-phase half-bridge circuit 19U are located near the left and right connections of the connection terminal 10A and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0073] Furthermore, the upper arm switching element 18B and lower arm switching element 18E of the V-phase half-bridge circuit 19V of the inverter circuit 28 are located near the left and right of the connection terminal 10B and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. In addition, the upper arm switching element 18C and lower arm switching element 18F of the W-phase half-bridge circuit 19W of the inverter circuit 28 are located near the left and right of the connection terminal 10C and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0074] Furthermore, the upper arm switching element 18A1 and lower arm switching element 18D1 of another U-phase half-bridge circuit 19U1 are located near the left and right of the connection terminal 10D and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. Also, the upper arm switching element 18B1 and lower arm switching element 18E1 of another V-phase half-bridge circuit 19V1 are located near the left and right of the connection terminal 10E and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6. Furthermore, the upper arm switching element 18C1 and lower arm switching element 18F1 of another W-phase half-bridge circuit 19W1 are located near the left and right of the connection terminal 10F and are arranged in a heat exchange relationship on the side of the partition wall 3 facing the inverter housing 6.

[0075] Thus, in this embodiment as well, each switching element 18A~18F, 18A1~18F1 is distributed in pairs, corresponding to each of the connection terminals 10A~10F, and is provided on the partition wall 3. Furthermore, the terminal portions 22 of each switching element 18A~18F, 18A1~18F1 are positioned on the substrate 17 side with the respective connection terminals 10A~10F facing outwards, and are electrically connected to the substrate 17 of the inverter 16.

[0076] In this embodiment as well, the inverter 16 having the inverter circuit 28 is configured to supply power to the motor 8 via connection terminals 10A to 10F and busbar 5. Furthermore, each switching element 18A1 to 18F1 is in close contact with the partition wall 3 via insulating and / or heat dissipation sheets, and is in a heat exchange relationship with the partition wall 3 of the housing 2. It is cooled by the refrigerant drawn into the motor chamber 4 through the partition wall 3, and each switching element 18A1 to 18F1 itself dissipates heat to the refrigerant through the partition wall 3. The rest is the same as in the embodiment described above.

[0077] Next, Figure 13 shows an example of the control operation of the control unit 21 of the inverter 16 in this embodiment. In this figure, cu, cv, and cw are normalized pulse width command values, and vu, vv, and vw are the voltages applied to the UVW phases of the motor 8, respectively. Also, Iu, Iv, and Iw are examples of currents flowing through the motor 8.

[0078] In this case as well, the control unit 21 applies the three-phase AC voltages vu, vv, and vw to the respective coils 9U, 9V, and 9W of the motor 8 by switching (ON / OFF) the switching elements 18A to 18F of the half-bridge circuits 19U, 19V, and 19W of each phase of the inverter circuit 28. On the other hand, the operation of the upper arm switching elements 18A1 to 18C1 of the half-bridge circuits 19U1, 19V1, and 19W1 of each phase is reversed. That is, when the upper arm switching element 18A of the half-bridge circuit 19U is ON, the lower arm switching element 18D1 of the opposing half-bridge circuit 19U1 is turned ON.

[0079] By doing so, the voltage applied to the coils 9U to 9W of each phase (UVW) of motor 8 can be set within a range of plus or minus 2, and even in simple operation, judging by the amplitude, it becomes possible to apply a voltage of approximately twice the original voltage. The maximum voltage that can be applied is approximately 1.5 to 2 times the original voltage (the specific value varies depending on the modulation method).

[0080] In this embodiment as well, the six connection terminals 10A to 10F that protrude from the motor 8 in the direction of the partition wall 3 are provided in a distributed manner, and the switching elements 18A to 18F and 18A1 to 18F1 are provided in a distributed manner on the partition wall 3 corresponding to each connection terminal 10A to 10F. As a result, the lengths (wiring lengths) of the wiring 33U to 33W and 33U1 to 33W1 to each phase of the motor 8 can be made equal or close to equal. This makes it possible to equalize the surge voltage in the wiring to each phase of UVW and to equalize the loss / heat generation of each switching element 18A to 18F and 18A1 to 18F1.

[0081] Furthermore, in this embodiment as well, two switching elements 18A to 18F and two 18A1 to 18F1 are provided in the partition wall 3, corresponding to each of the connection terminals 10A to 10F, and located near them. As a result, the wiring length from switching elements 18A and 18D to connection terminal 10A, from switching elements 18B and 18E to connection terminal 10B, from switching elements 18C and 18F to connection terminal 10C, from switching elements 18A1 and 18D1 to connection terminal 10D, from switching elements 18B1 and 18E1 to connection terminal 10E, and from switching elements 18C1 and 18F1 to connection terminal 10F is shortened, further reducing surge voltage.

[0082] Furthermore, in this embodiment as well, since each connection terminal 10A to 10F is provided at equal intervals in the circumferential direction of the motor 8, it becomes possible to smoothly equalize the wiring length (length of wiring 33U to 33W, 33U1 to 33W1) to each phase UVW of the motor 8.

[0083] Furthermore, the increased flexibility in the arrangement of switching elements 18A~18F and 18A1~18F1 allows for the number of connection terminals to increase to 6 (10A~10F) and the number of switching elements to 12 (18A~18F and 18A1~18F1), while still satisfying the insulation withstand voltage and cooling efficiency requirements without increasing the dimensions of housing 2. This enables the adoption of an inverter 16 like the inverter circuit 28 in Figure 11, allowing for smooth handling of a wider voltage range.

[0084] Although the examples describe a switching element consisting of an IGBT, a MOSFET may also be used. Furthermore, the specific configurations shown in each example are not limited to those shown and can be modified without departing from the spirit of the present invention. [Explanation of Symbols]

[0085] 1. Electric compressor 2 Housing 3 Bulkhead 4. Motor Room 5 Bus Bar 6. Inverter housing 7 Compression mechanism 8 motors 9 stata 10A~10F Connection Terminals 16 Inverters 17 circuit boards 18A~18H, 18A1~18F1 switching elements 19U, 19U1 U-phase inverter 19V, 19V 1V-phase inverter 19W, 19W1 W-phase inverter 21 Control Unit 28 Inverter Circuit 36 diodes

Claims

1. In an electric compressor equipped with an inverter that supplies power to a motor using multiple switching elements, A housing comprising a motor compartment in which the motor is built, and an inverter housing section in which the inverter is mounted, The partition wall between the motor room and the inverter housing, One end is electrically connected to the motor, and it is equipped with six connection terminals that protrude from the motor in the direction of the partition wall, Each connection terminal is provided at a distance, and the other end is electrically connected to the inverter by passing through the partition wall. The inverter comprises seven switching elements and one diode, and the switching elements and the diode are distributed and provided on the partition wall in a manner corresponding to each of the connection terminals, characterized in that the electric compressor is provided.

2. The electric compressor according to claim 1, characterized in that the switching element is located near each of the connection terminals and provided in the partition wall.

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