Control board for electric compressor, and electric compressor with the same

Abstract

To provide a control board for an electric compressor capable of suppressing the deterioration of current detection accuracy due to thermal electromotive force of the shunt resistor and to allow accurate current detection.SOLUTION: A control board 27 for an electric compressor is mounted with switching elements 28 constituting an inverter circuit 29 and shunt resistors 3U to 3W for detecting a phase current. One terminal of both terminals of the shunt resistors is connected to the switching element by current wiring patterns 46 to 48, and the other terminal is connected to a ground wiring pattern 1. The current wiring patterns and the ground wiring pattern are formed in different layers and overlapped in a board thickness direction to enable mutual heat exchange through an insulating resin 53.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an electric compressor control board for controlling an electric compressor, and an electric compressor including the same. [Background technology]

[0002] In an air conditioner for vehicles for conditioning the interior of an electric vehicle, an electric compressor for vehicles that has a motor and a compression mechanism driven by the motor in a housing is used instead of an engine-driven compressor. In this case, an inverter circuit composed of multiple switching elements converts a DC voltage from a high-voltage (e.g., about DC 300 V) on-board battery into an AC voltage, which is then applied to the motor.

[0003] The switching elements of the inverter circuit are controlled by a control device configured on a control board, and in this case the motor is controlled by detecting the current (phase current) flowing through each phase using a shunt resistor. In addition, miniaturization is required for such electric compressors due to the installation space, and therefore the density of electronic components on the control board is increasing (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-207310 A Summary of the Invention [Problem to be solved by the invention]

[0005] Fig. 5 shows a plan view of a conventional control board 100 for this type of electric compressor. In the figure, reference numeral 1 denotes a ground wiring pattern connected to the negative pole (-) of a battery (DC power source) mounted on a vehicle (not shown), reference numeral 2 denotes a terminal hole to which the terminals (three terminals) of multiple switching elements constituting an inverter circuit (not shown) are soldered, and reference numerals 3U, 3V, and 3W denote shunt resistors for detecting the current (phase current) flowing through each switching element.

[0006] Since the switching elements are provided for three phases in the upper arm and the lower arm, six terminal holes 2 are formed. Also, three shunt resistors 3U, 3V, 3W are provided since they are connected to the switching elements of the lower arms. In this case, the shunt resistors 3U to 3W were conventionally provided near the switching elements (terminal holes 2), with one terminal 6 connected to the switching elements (terminal holes 2) of the lower arms by short current wiring patterns 101, and the other terminals 7 connected to the ground wiring patterns 1.

[0007] Here, a large current flows through the switching elements, which are power devices such as IGBTs, and therefore the switching elements have large losses and tend to become hotter than the surrounding electronic components. On the other hand, when the shunt resistors 3U to 3W are wired in close proximity to the switching elements as shown in Fig. 5, a temperature difference occurs between one terminal 6 and the other terminal 7 of the shunt resistors 3U to 3W due to the effect of the heat transferred from them, and the current detection accuracy deteriorates due to the thermoelectromotive force.

[0008] The present invention has been made to solve the above-mentioned conventional technical problems, and has an object to provide a control board for an electric compressor that can suppress deterioration of current detection accuracy due to the thermoelectromotive force of a shunt resistor and perform accurate current detection, and an electric compressor equipped with the control board. [Means for solving the problem]

[0009] The control board for an electric compressor of the invention of claim 1 is equipped with a switching element that constitutes an inverter circuit and a shunt resistor for detecting a phase current, and one of the two terminals of the shunt resistor is connected to the switching element by a current wiring pattern and the other terminal is connected to a ground wiring pattern. The current wiring pattern and the ground wiring pattern are formed in different layers and overlapped in the thickness direction of the board, allowing heat exchange between them via an insulating resin.

[0010] The control board for an electric compressor of the invention of claim 2 is characterized in that in the above invention, a plurality of switching elements and shunt resistors are provided, one terminal of each shunt resistor is connected to each switching element by a current wiring pattern, the other terminal of each shunt resistor is connected to a ground wiring pattern, and the ground wiring pattern is overlapped with each current wiring pattern connected to adjacent switching elements.

[0011] The control board for an electric compressor of the invention of claim 3 is mounted with a plurality of switching elements that constitute an inverter circuit and a plurality of shunt resistors for detecting each phase current, one of both terminals of each shunt resistor is connected to each switching element by a current wiring pattern, and the other terminal is connected to a ground wiring pattern, and the current wiring pattern is formed along the switching elements and longer than the width of the switching elements.

[0012] The electric compressor control board according to the invention of claim 4 is characterized in that in the above invention, the current wiring pattern is formed wider than the width of the terminal of the shunt resistor, and a plurality of vias are formed.

[0013] The control board for an electric compressor of the invention of claim 5 is characterized in that in the above invention, the current wiring pattern and the ground wiring pattern are formed in different layers and overlapped in the thickness direction of the board, thereby enabling heat exchange between them via insulating resin.

[0014] The control board for an electric compressor of the invention of claim 6 is mounted with a switching element that constitutes an inverter circuit and a shunt resistor for detecting a phase current, one of both terminals of the shunt resistor is connected to the switching element by a current wiring pattern and the other terminal is connected to a ground wiring pattern, and the current wiring pattern is formed to be wider than the width of the terminals of the shunt resistor.

[0015] The control board for an electric compressor of the invention of claim 7 is characterized in that it is mounted with a switching element that constitutes an inverter circuit and a shunt resistor for detecting a phase current, one of both terminals of the shunt resistor is connected to the switching element by a current wiring pattern and the other terminal is connected to a ground wiring pattern, and a plurality of vias are formed in the current wiring pattern.

[0016] The electric compressor of the invention of claim 8 is characterized in that it comprises, within a housing, an electric compressor control board of any of the above inventions, a motor powered by an inverter circuit, and a compression mechanism driven by the motor. Effect of the Invention

[0017] According to the inventions of claims 1 and 5, in a control board for an electric compressor, which is equipped with a switching element constituting an inverter circuit and a shunt resistor for detecting a phase current, and which has both terminals of the shunt resistor, one of which is connected to the switching element by a current wiring pattern and the other of which is connected to a ground wiring pattern, the current wiring pattern and the ground wiring pattern are formed in different layers and overlapped in the thickness direction of the board, making it possible to exchange heat with each other via the insulating resin. Therefore, it becomes possible to eliminate or suppress the occurrence of a temperature difference between one terminal and the other terminal of the shunt resistor by transmitting heat from the high-temperature switching element to the current wiring pattern via the insulating resin to the ground wiring pattern which has a relatively low temperature.

[0018] This makes it possible to eliminate or suppress deterioration in current detection accuracy caused by thermoelectromotive force resulting from a temperature difference between both terminals of the shunt resistor, thereby enabling accurate current detection.

[0019] In particular, when a plurality of switching elements and shunt resistors are provided as in the invention of claim 2, one terminal of each shunt resistor is connected to each switching element by a current wiring pattern, and the other terminal of each shunt resistor is connected to a ground wiring pattern, by overlapping the ground wiring pattern with each current wiring pattern connected to adjacent switching elements, it becomes possible to easily and effectively exchange heat between each current wiring pattern and the ground wiring pattern.

[0020] In addition, according to the invention of claim 3, in a control board for an electric compressor which is implemented with a plurality of switching elements constituting an inverter circuit and a plurality of shunt resistors for detecting each phase current, and in which one of both terminals of each shunt resistor is connected to each switching element by a current wiring pattern and the other terminal is connected to a ground wiring pattern, the current wiring pattern is formed along the switching elements and longer than the width of the switching elements, thereby reducing the heat transferred from the switching elements, which become hot, to one terminal of the shunt resistor via the current wiring pattern, and eliminating or suppressing the occurrence of a temperature difference between one terminal and the other terminal of the shunt resistor.

[0021] This makes it possible to eliminate or suppress deterioration in current detection accuracy caused by thermoelectromotive force resulting from a temperature difference between both terminals of the shunt resistor, thereby enabling accurate current detection.

[0022] According to the inventions of claims 6 and 4, in a control board for an electric compressor, which is equipped with a switching element that constitutes an inverter circuit and a shunt resistor for detecting a phase current, and which has both terminals of the shunt resistor, one of which is connected to the switching element by a current wiring pattern and the other terminal of which is connected to a ground wiring pattern, the current wiring pattern is formed to be wider than the width of the terminals of the shunt resistor, thereby reducing heat generation in the current wiring pattern due to heat transferred from the switching element, which becomes hot, and eliminating or suppressing the occurrence of a temperature difference between one terminal and the other terminal of the shunt resistor.

[0023] This makes it possible to eliminate or suppress deterioration in current detection accuracy caused by thermoelectromotive force resulting from a temperature difference between both terminals of the shunt resistor, thereby enabling accurate current detection.

[0024] Furthermore, according to the inventions of claims 7 and 4, in a control board for an electric compressor, which is equipped with a switching element constituting an inverter circuit and a shunt resistor for detecting a phase current, and in which one of both terminals of the shunt resistor is connected to the switching element by a current wiring pattern and the other terminal is connected to a ground wiring pattern, a plurality of vias are formed in the current wiring pattern, thereby making it possible to improve the heat dissipation property of the current wiring pattern.

[0025] This makes it possible to dissipate heat transmitted from the high-temperature switching element to one terminal of the shunt resistor via the current wiring pattern, thereby eliminating or suppressing the occurrence of a temperature difference between one terminal and the other terminal of the shunt resistor.This eliminates or suppresses the deterioration of current detection accuracy caused by thermoelectromotive force caused by a temperature difference between the two terminals of the shunt resistor, making it possible to perform accurate current detection.

[0026] The electric compressor control board of each of the above inventions is extremely effective for an electric compressor that includes, within a housing, the electric compressor control board, a motor powered by an inverter circuit, and a compression mechanism driven by the motor, as in the invention of claim 8. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic cross-sectional view of an electric compressor according to an embodiment of the present invention; [Diagram 2] FIG. 2 is an electric circuit diagram of an inverter circuit of the electric compressor of FIG. [Diagram 3] 2 is an enlarged view of a main portion of the electric compressor control board shown in FIG. 1. [Figure 4] FIG. 2 is a schematic cross-sectional view of a control board for the electric compressor of FIG. [Diagram 5] FIG. 1 is a plan view of a conventional electric compressor control board. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. First, an electric compressor (a so-called inverter-integrated electric compressor) 11 according to an embodiment to which the present invention is applied will be described with reference to Fig. 1. The electric compressor 11 according to the embodiment constitutes a part of a refrigerant circuit of a vehicle air conditioner mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle.

[0029] (1) Configuration of Electric Compressor 1 1, an electric compressor 11 of the embodiment has a cylindrical housing 12 made of metal (made of aluminum of a predetermined thickness in the embodiment). The inside of this housing 12 is divided into a compression mechanism accommodating section 14 and an inverter accommodating section 16 by a partition wall 13 that intersects with the axial direction of the housing 12. The compression mechanism accommodating section 14 accommodates, for example, a scroll type compression mechanism 17 and a motor 18 that drives the compression mechanism 17.

[0030] In this case, the motor 18 of the embodiment is an interior permanent magnet synchronous motor (IPMSM) that is composed of a stator 19 fixed to the housing 12 and a rotor 21 that rotates inside the stator 19.

[0031] A bearing portion 22 is formed in the center of the partition wall 13 on the compression mechanism accommodating portion 14 side, one end of a drive shaft 23 of the rotor 21 is supported by this bearing portion 22, and the other end of the drive shaft 23 is connected to the compression mechanism 17. A suction port 24 is formed near the partition wall 13 at a position corresponding to the compression mechanism accommodating portion 14 of the housing 12, and when the rotor 21 (drive shaft 23) of the motor 18 rotates to drive the compression mechanism 17, a low-temperature refrigerant, which is a working fluid, flows from the suction port 24 into the compression mechanism accommodating portion 14 of the housing 12, and is sucked into the compression mechanism 17 and compressed.

[0032] The refrigerant compressed by the compression mechanism 17 and having a high temperature and pressure is discharged from a discharge port (not shown) into the refrigerant circuit outside the housing 12. The low-temperature refrigerant that flows in from the suction port 24 passes near the partition wall 13, passes around the motor 18, and is sucked into the compression mechanism 17, thereby cooling the motor 18 and the partition wall 13 as well.

[0033] An inverter device 26 that supplies power to the motor 18 to control its drive is accommodated in the inverter accommodating section 16 that is separated from the compression mechanism accommodating section 14 by the partition wall 13. In this case, the inverter device 26 is configured to supply power to the motor 18 via sealed terminals and lead wires that penetrate the partition wall 13.

[0034] (2) Structure of inverter device 26 The inverter device 26 of the embodiment is composed of a control board 27 serving as a control board for an electric compressor of the present invention, six switching elements 28 mounted on one side of the control board 27, and an HV connector, an LV connector, etc. (not shown). In the embodiment, each switching element 28 is composed of an insulated gate bipolar transistor (IGBT) incorporating a MOS structure in the gate portion.

[0035] In this case, the switching elements 28 constitute a three-phase inverter circuit 29 described later, and terminals 32 (the collector terminal, emitter terminal, and gate terminal are collectively referred to by the reference symbol 32) of each switching element 28 are connected to the control board 27. The inverter device 26 thus assembled is then accommodated in the inverter accommodating section 16 with the side on which the switching elements 28 are located facing the partition wall 13, attached to the partition wall 13, and closed with a cover 33.

[0036] In this case, the control board 27 is fixed to the partition wall 13 of the housing 12 by a boss portion 34 standing from the partition wall 13, with one side facing the partition wall 13. With the inverter device 26 attached to the partition wall 13 in this manner, each switching element 28 is in close contact with the partition wall 13 directly or via a predetermined insulating and thermally conductive material, and is in a heat exchange relationship with the partition wall 13 of the housing 12, so that each switching element 28 is cooled by the sucked refrigerant via the partition wall 13. Reference numeral 36 denotes a control device arranged on the other side of the control board 27.

[0037] (3) Electrical circuit of inverter circuit 29 2 shows the electric circuit of the inverter circuit 29 mounted on the control board 27 and the control device 36. The inverter circuit 29 has a U-phase inverter 38U, a V-phase inverter 38V, and a W-phase inverter 38W, and the inverters 38U to 38W of each phase have an upper arm switching element 28 and a lower arm switching element 28. Furthermore, a flywheel diode 39 is connected in inverse parallel to each switching element 28.

[0038] The collector terminal of switching element 28 of the upper arm of inverter circuit 29 is connected to power supply wiring pattern 41 connected to the positive electrode (+) of a battery (DC power supply) (not shown) mounted on the vehicle, and the emitter terminal of switching element 28 of the lower arm is connected to ground wiring pattern 1 connected to the negative electrode (-) of the battery via shunt resistors 3U, 3V, and 3W (described later). The emitter terminal of switching element 28 of the upper arm of U-phase inverter 38U and the collector terminal of switching element 28 of the lower arm are connected by intermediate path 41U, and this intermediate path 41U is connected to the U-phase stator coil of motor 18 by output path 42U.

[0039] Furthermore, the emitter terminals of the switching elements 28 of the upper arms and the collector terminals of the switching elements 28 of the lower arms of the V-phase inverter 38V are connected by an intermediate path 41V, and this intermediate path 41V is connected to the V-phase stator coil of the motor 18 by an output path 42V. Furthermore, the emitter terminals of the switching elements 28 of the upper arms and the collector terminals of the switching elements 28 of the lower arms of the W-phase inverter 38W are connected by an intermediate path 41W, and this intermediate path 41W is connected to the W-phase stator coil of the motor 18 by an output path 42W.

[0040] Further, shunt resistors 3U, 3V, 3W for detecting the phase currents of each of the UVW phases are connected between the emitter terminals of the switching elements 28 of the lower arms of the UVW phase inverters 38U-38W and the ground wiring pattern 1, and are mounted on the other side of the control board 27. Each of the shunt resistors 3U-3W constitutes a control device 36. A microprocessor (microcomputer) included in the control device 36 detects the phase currents of each of the UVW phases based on the voltage between one terminal 6 and the other terminal 7 of each of the shunt resistors 3U, 3V, 3W, and switches each of the switching elements 28 of the inverter circuit 29 based on the detected phase currents, thereby vector-controlling the motor 18.

[0041] (4) Configuration of control board 27 Next, the structure of control board 27 of the present invention will be described with reference to Figures 3 to 5. Note that in Figures 3 and 4, the same reference numerals as in Figure 5 denote the same or similar functions. Figure 3 is an enlarged plan view of shunt resistors 3U to 3W of control board 27 of the present invention, and Figure 4 is a schematic cross-sectional view for explaining the layer structure of control board 27.

[0042] As in Figure 5, 1 in Figure 3 is a ground wiring pattern connected to the negative pole (-) of a battery (DC power source) mounted on a vehicle (not shown), and 2 is a terminal hole to which the terminals 32 (the three terminals mentioned above) of the six switching elements 28 that constitute the inverter circuit 29 are soldered, with the terminals 32 of the switching element 28 of the lower arm of U-phase inverter 38U being soldered to the three on the left side, the terminals 32 of the switching element 28 of the lower arm of V-phase inverter 38V being soldered to the three in the middle, and the terminals 32 of the switching element 28 of the lower arm of W-phase inverter 38W being soldered to the three on the right side.

[0043] 3, terminal hole 2 to which the emitter terminal of switching element 28 of the lower arm of U-phase inverter 38U is connected is indicated by 2U, terminal hole 2 to which the emitter terminal of switching element 28 of the lower arm of V-phase inverter 38V is connected is indicated by 2V, and terminal hole 2 to which the emitter terminal of switching element 28 of the lower arm of W-phase inverter 38W is connected is indicated by 2W. The configuration other than the configuration related to the arrangement and wiring of shunt resistors 3U to 3W described later is the same as in FIG.

[0044] In the embodiment, shunt resistors 3U and 3V are mounted on the other side of control board 27 near terminal hole 2 to which switching element 28 of the lower arm of U-phase inverter 38U is connected, and shunt resistor 3W is mounted on the other side of control board 27 near terminal hole 2 to which switching element 28 of the lower arm of V-phase inverter 38V is connected.

[0045] A U-phase current wiring pattern 46 is formed on the other surface of the control board 27 between one terminal 6 of the shunt resistor 3U and the terminal hole 2U, a V-phase current wiring pattern 47 is formed on the other surface of the control board 27 between one terminal 6 of the shunt resistor 3V and the terminal hole 2V, and a W-phase current wiring pattern 48 is formed on the other surface of the control board 27 between one terminal 6 of the shunt resistor 3W and the terminal hole 2W. The other terminals 7 of the shunt resistors 3U to 3W are connected to a common ground wiring pattern 1 formed over a wide area on the other surface of the control board 27.

[0046] In the present invention, the U-phase current wiring pattern 46 is formed along the switching element 28 of the lower arm of the U-phase inverter 38U adjacent to the shunt resistor 3U with a dimension longer than the width of the switching element 28, and is further wider than the width of one terminal 6 of the shunt resistor 3U. The V-phase current wiring pattern 47 is formed along the switching element 28 of the lower arm of the V-phase inverter 38V with a dimension longer than the width of the switching element 28, and is further wider than the width of one terminal 6 of the shunt resistor 3V. The W-phase current wiring pattern 48 is formed along the switching element 28 of the lower arm of the W-phase inverter 38W with a dimension longer than the width of the switching element 28, and is further wider than the width of one terminal 6 of the shunt resistor 3W. Each of the current wiring patterns 46 to 48 has a plurality of vias 51 formed therein.

[0047] Furthermore, in the present invention, the common ground wiring pattern 1 and the current wiring patterns 46, 47, 48 connected to the adjacent switching elements 28 respectively overlap in the thickness direction (substrate thickness direction) of the control board 27. This overlapping portion is indicated by 52 in Fig. 3. This overlapping structure will be described with reference to Fig. 4 showing a cross section of the control board 27.

[0048] In Fig. 4, 53 denotes an insulating resin that constitutes the control board 27. The control board 27 in the embodiment has a six-phase structure having first to sixth phase patterns, in which the current wiring patterns 46 to 48 are formed in the first phase and connected to the third, fourth and sixth phase patterns by vias 51 in the embodiment, and the ground wiring pattern 1 is formed in the second and fifth phase patterns different from the current wiring patterns 46 to 48 (shown in a see-through manner in Fig. 3).

[0049] One terminal 6 of each of the shunt resistors 3U to 3W is connected to each of the current wiring patterns 46 to 48 in the first phase of the pattern, and the other terminal 7 is connected to the ground wiring pattern 1 through a pad 56 and a via 55.

[0050] 4 shows a state in which the emitter terminal of switching element 28 of the lower arm of U-phase inverter 38U is connected to terminal hole 2U with solder 54, and the emitter terminal of switching element 28 of the lower arm of V-phase inverter 38V is connected to terminal hole 2V with solder 54. The emitter terminal of switching element 28 of the lower arm of W-phase inverter 38W is also connected to terminal hole 2W with solder 54.

[0051] In the overlapping portion 52 described above, each of the current wiring patterns 46, 47, 48 overlaps with the common ground wiring pattern 1 in the thickness direction of the control board 27, and the current wiring patterns 46 to 48 and the ground wiring pattern 1 exchange heat with each other via the insulating resin 53 (the overlapping portion 52 is the heat exchange area).

[0052] As a result, the heat of the current wiring pattern 46 is transferred to the other terminal 7 of the shunt resistor 3U via the insulating resin 53 and the ground wiring pattern 1 as shown by the arrow in Fig. 3, and the heat of the current wiring pattern 46 is further transferred to the other terminal 7 of the shunt resistor 3V as shown by the arrow in Fig. 3 via the insulating resin 53 and the ground wiring pattern 1. In addition, the heat of the current wiring pattern 47 is transferred to the other terminal 7 of the shunt resistor 3W as shown by the arrow in Fig. 3 via the insulating resin 53 and the ground wiring pattern 1.

[0053] As described above, a large current flows through the switching element 28, which is a power device such as an IGBT, and this causes a large loss and tends to become hot. Therefore, due to the heat transmitted through the current wiring patterns 46-48, the temperature of one terminal 6 of each of the shunt resistors 3U-3W tends to become higher than the other terminal 7 connected to the ground wiring pattern 1, which is relatively cool, and the thermoelectromotive force generated by this temperature difference deteriorates the current detection accuracy.

[0054] However, in the present invention, the current wiring patterns 46-48 and the ground wiring pattern 1 are formed on different pattern layers and overlapped in the thickness direction of the control board 27, allowing them to exchange heat with each other via the insulating resin 53. Therefore, the heat transferred from the switching elements 28, which become hot, to the current wiring patterns 46-48 is transferred via the insulating resin 53 to the ground wiring pattern 1, which has a relatively low temperature, thereby eliminating or suppressing the occurrence of a temperature difference between one terminal 6 and the other terminal 7 of the shunt resistors 3U-3W.

[0055] This eliminates or suppresses deterioration in current detection accuracy caused by thermoelectromotive force caused by a temperature difference between the terminals 6, 7 of the shunt resistors 3U to 3W, thereby enabling accurate current detection.

[0056] In particular, in the embodiment, the ground wiring pattern 1 overlaps with each of the current wiring patterns 46, 47 connected to the switching elements 28 adjacent to each other, so that heat exchange can be easily and effectively performed between each of the current wiring patterns 46, 47 and the ground wiring pattern 1.

[0057] In addition, since the current wiring patterns 46-48 are formed along the switching elements 28 and longer than the width of the switching elements 28, the heat transferred from the switching elements 28, which become hot, to one terminal 6 of each of the shunt resistors 3U-3W via the current wiring patterns 46-48 is reduced, thereby eliminating or suppressing the occurrence of a temperature difference between one terminal 6 and the other terminal 7 of each of the shunt resistors 3U-3W.

[0058] This also makes it possible to eliminate or suppress deterioration in current detection accuracy caused by thermoelectromotive force caused by a temperature difference between the terminals 6, 7 of the shunt resistors 3U to 3W, and to perform accurate current detection.

[0059] Furthermore, since the current wiring patterns 46-48 are formed wider than the width of the terminals 6 of the shunt resistors 3U-3W, the heat generated in the current wiring patterns 46-48 due to the heat transferred from the switching elements 28, which become hot, is reduced, thereby eliminating or suppressing the occurrence of a temperature difference between one terminal 6 and the other terminal 7 of the shunt resistors 3U-3W.

[0060] This also makes it possible to eliminate or suppress deterioration in current detection accuracy caused by thermoelectromotive force caused by a temperature difference between the terminals 6, 7 of the shunt resistors 3U to 3W, and to perform accurate current detection.

[0061] Furthermore, since a plurality of vias 51 are formed in the current wiring patterns 46-48, it is possible to improve the heat dissipation of the current wiring patterns 46-48. This also makes it possible to dissipate the heat transferred from the high-temperature switching elements 28 to the one terminal 6 of each of the shunt resistors 3U-3W via the current wiring patterns 46-48, thereby eliminating or suppressing the occurrence of a temperature difference between the one terminal 6 and the other terminal 7 of each of the shunt resistors 3U-3W, thereby eliminating or suppressing the deterioration of current detection accuracy caused by the thermoelectromotive force caused by the temperature difference between the terminals 6, 7 of the shunt resistors 3U-3W, and thus making it possible to perform accurate current detection.

[0062] In the embodiment, the current wiring patterns 46, 47 and the ground wiring pattern 1 are overlapped, but in the inventions other than claims 1, 2, and 5, the current wiring patterns 46-48 are formed longer than the width of the switching element 28, but in the inventions other than claims 3-5, the current wiring patterns 46-48 may be shorter than the width of the switching element 28. In the embodiment, the current wiring patterns 46-48 are formed wider than the width of the terminals 6 of the shunt resistors 3U-3W, but in the inventions other than claims 4-6, the current wiring patterns 46-48 may be narrower than the width of the terminals 6. In the embodiment, the current wiring patterns 46-48 are formed with vias 51, but in the inventions other than claims 4, 5, and 7, the current wiring patterns 46-48 may be formed without vias. [Explanation of symbols]

[0063] 1 Ground wiring pattern 2, 2U~2W terminal hole 3U~3W Shunt Resistor 6 One terminal 7 The other terminal 11 Electric compressor 12. Chassis 17 Compression mechanism 18 Motor 27 Control board (control board for electric compressor) 28 Switching elements 29 Inverter Circuit 32 terminals 46~48 Current wiring pattern 51 Beer 53 Insulating resin

Claims

1. A control board for an electric compressor, comprising: a switching element constituting an inverter circuit; and a shunt resistor for detecting a phase current, one of both terminals of the shunt resistor being connected to the switching element by a current wiring pattern and the other terminal being connected to a ground wiring pattern, a current wiring pattern and a ground wiring pattern formed on different layers and overlapping each other in a thickness direction of the board, thereby enabling heat exchange between them via an insulating resin.

2. A plurality of the switching elements and the shunt resistors are provided, One terminal of each of the shunt resistors is connected to each of the switching elements by the current wiring pattern, and the other terminal of each of the shunt resistors is connected to the ground wiring pattern; 2. The electric compressor control board according to claim 1, wherein the ground wiring pattern overlaps with each of the current wiring patterns connected to the switching elements adjacent to each other.

3. A control board for an electric compressor is provided with a plurality of switching elements constituting an inverter circuit and a plurality of shunt resistors for detecting each phase current, and one of both terminals of each shunt resistor is connected to each of the switching elements by a current wiring pattern and the other terminal is connected to a ground wiring pattern, 4. A control board for an electric compressor, comprising: a current wiring pattern formed along the switching elements and having a length greater than a width of the switching elements.

4. 4. The control board for an electric compressor according to claim 3, wherein the current wiring pattern is formed to be wider than the width of the terminals of the shunt resistor, and a plurality of vias are formed therein.

5. 5. The control board for an electric compressor according to claim 4, wherein the current wiring pattern and the ground wiring pattern are formed on different layers and overlap each other in a thickness direction of the board, thereby enabling heat exchange between them via an insulating resin.

6. A control board for an electric compressor, comprising: a switching element constituting an inverter circuit; and a shunt resistor for detecting a phase current, one of both terminals of the shunt resistor being connected to the switching element by a current wiring pattern and the other terminal being connected to a ground wiring pattern, 4. A control board for an electric compressor, comprising: a current wiring pattern formed to be wider than a terminal of the shunt resistor.

7. A control board for an electric compressor, comprising: a switching element constituting an inverter circuit; and a shunt resistor for detecting a phase current, one of both terminals of the shunt resistor being connected to the switching element by a current wiring pattern and the other terminal being connected to a ground wiring pattern, A control board for an electric compressor, comprising: a current wiring pattern having a plurality of vias formed therein.

8. 8. An electric compressor comprising: a control board for an electric compressor according to claim 1; a motor powered by the inverter circuit; and a compression mechanism driven by the motor, all of which are housed in a housing.

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