Vehicle-mounted electric compressor

Abstract

The invention provides a vehicle-mounted electric compressor which can improve the effect of reducing noise generated by an inverter circuit and the like without increasing the electrostatic capacitance of a Y capacitor. The vehicle-mounted electric compressor (1) is provided with an inverter substrate (17) in a metal box body (2). The inverter substrate (17) is provided with an inverter circuit (34) which converts direct current from a high-voltage battery (41) into alternating current and applies the alternating current to a motor (8). The vehicle-mounted electric compressor (1) includes: a common-mode coil (54) into which high-voltage power lines (46, 47) from a high-voltage battery (41) are inserted; a Y capacitor (56) connected between the high-voltage power supply lines (46, 47) and the case (2); and an inductor (57) connected in series with the Y capacitor (56).

Description

Technical Field

[0001] The present invention relates to an in-vehicle electric compressor having an inverter substrate on which an inverter circuit is mounted in a housing. Background Art

[0002] In a vehicle air conditioning device for air conditioning the interior of an electric vehicle, an in-vehicle electric compressor having an electric motor is used instead of an engine-driven compressor. In this case, a DC voltage from a vehicle-mounted battery at a high voltage (e.g., about DC300V) is converted into an AC voltage by an inverter circuit composed of a plurality of switching elements and applied to the electric motor.

[0003] Moreover, the switching elements of the inverter circuit are switched and controlled by a control device. In this case, however, a high-voltage circuit including a high-voltage power line from the vehicle-mounted battery and a low-voltage circuit including the control device are arranged on the same inverter substrate and mounted in an inverter housing portion formed in the housing of the in-vehicle electric compressor.

[0004] In addition, a common-mode choke coil is connected to the high-voltage power line of the high-voltage circuit, and a Y capacitor is connected between the high-voltage power line and the housing to return a common-mode noise current flowing out from the inverter circuit or the like to the noise source (recover the noise), thereby improving EMI (for example, refer to Patent Document 1).

[0005] Patent Document 1: Japanese Patent No. 6571358

[0006] Here, an LPF (Low Path Filter) composed of a common-mode choke coil and a Y capacitor is effective in reducing noise in a relatively low frequency band of about 1 MHz. In order to reduce high-frequency noise in the VHF frequency band of 30 MHz to 50 MHz generated when the switching elements of the inverter circuit are switched, a resonant filter composed of a Y capacitor alone (and parasitic inductance) is effective, but its noise reduction effect is strongly affected by the location (impedance characteristics) on the inverter substrate.

[0007] Therefore, conventionally, a plurality of mounting patterns are formed in advance so that a plurality of Y capacitors can be arranged at various positions on the inverter substrate. At the time of EMI testing during trial production, an operation of verifying the noise reduction effect in the VHF frequency band is performed by identifying a Y capacitor at a location (impedance) effective for high-frequency noise.

[0008] However, if a plurality of mounting patterns are arranged on the inverter substrate, there is a problem that the size of the substrate increases, resulting in an increase in the size of the in-vehicle electric compressor. In addition, if unnecessary mounting patterns (unmounted patterns) are sorted and merged for mass production after finding an effective combination of locations of the Y capacitors, there is also a problem that the EMI result changes due to the change in the arrangement.

[0009] Moreover, the Y-capacitor between the high-voltage power line and the case (grounded to the vehicle chassis) needs to maintain sufficient withstand voltage to ensure vehicle safety. However, there is a limit in product design for the withstand voltage of each Y-capacitor. In practice, about two to four Y-capacitors are connected in series for use. Currently, the widely used Y-capacitors in the in-vehicle product lineup use products with the maximum withstand voltage and maximum electrostatic capacitance. Therefore, it is difficult to increase the electrostatic capacitance by reselecting components. Thus, when increasing the capacitance to improve EMI in the VHF band, the cost increases significantly by further connecting in parallel multiple Y-capacitor groups each having two to four Y-capacitors connected in series. Summary of the Invention

[0010] The present invention is completed to solve the above-mentioned existing technical problems, and its object is to provide an in-vehicle electric compressor that can improve the noise reduction effect generated from an inverter circuit or the like without increasing the electrostatic capacitance of the Y-capacitor.

[0011] The in-vehicle electric compressor of the present invention includes an inverter substrate in a metal case. The inverter substrate is equipped with an inverter circuit that converts DC from an in-vehicle battery into AC and applies it to the motor, and it includes: a common-mode coil inserted into the high-voltage power line from the in-vehicle battery; a Y-capacitor connected between the high-voltage power line and the case; and an inductor connected in series with the Y-capacitor.

[0012] Based on the above invention, the in-vehicle electric compressor of the invention of Mode 2 has the Y-capacitor composed of a ceramic capacitor group in which a plurality of surface-mounted ceramic capacitors are connected in series, and the inductor is composed of a surface-mounted chip inductor or chip bead.

[0013] Based on the invention of Mode 1, the in-vehicle electric compressor of the invention of Mode 3 makes the resonance frequency of the series circuit of the inductor and the Y-capacitor shift downward.

[0014] Based on the invention of Mode 1, the in-vehicle electric compressor of the invention of Mode 4 has, on the inverter substrate, mounting patterns of Y-capacitors arranged at multiple positions, and the inductor is connected to at least one of the Y-capacitors.

[0015] Based on the above inventions, the in-vehicle electric compressor of the invention of Mode 5 has a high-voltage circuit and a low-voltage circuit configured on the inverter substrate. The high-voltage circuit includes the high-voltage power line from the in-vehicle battery, the Y-capacitor, and the inductor, and the low-voltage circuit includes a control device for controlling the inverter circuit.

[0016] According to the present invention, an in-vehicle electric compressor having an inverter substrate on which an inverter circuit that converts direct current of a vehicle-mounted battery into alternating current and applies it to a motor is installed, and including the inverter substrate in a metal housing, includes: a common-mode coil inserted into a high-voltage power supply line from the vehicle-mounted battery; a Y capacitor connected between the high-voltage power supply line and the housing; and an inductor connected in series with the Y capacitor. Therefore, without increasing the electrostatic capacitance of the Y capacitor, the resonance frequency of the series circuit of the Y capacitor and the inductor can be shifted downward.

[0017] Thus, even when the Y capacitor is composed of a series ceramic capacitor bank in which surface-mounted ceramic capacitors are connected in series and the combined capacitance is reduced and the resonance frequency becomes high, the switching surge noise in the VHF band generated when driving the motor of the in-vehicle electric compressor can be effectively returned to the inverter circuit as the noise source through the Y capacitor and the inductor and recovered, suppressing its outflow to the outside, and EMI can be improved.

[0018] Here, since the radiation noise generated from the control device is shielded by the metal housing accommodating the inverter substrate, there is no particular problem.

[0019] In addition, it is not necessary to further connect the series ceramic capacitor bank in parallel to increase the electrostatic capacitance. As long as an inexpensive inductor composed of a chip inductor or a chip bead is connected, a significant reduction in cost and miniaturization of the in-vehicle electric compressor can be achieved.

[0020] In addition, when a plurality of mounting patterns of the Y capacitor are arranged on the inverter substrate and the Y capacitor is mounted, since EMI can be improved by connecting the inductor in series with at least one of the Y capacitors, it is not necessary to perform the operation of sorting and combining them after confirming the mounting pattern effective for EMI during trial production as in the past, and the reduction in the reproducibility of EMI generated during the sorting and combining of the mounting patterns is also eliminated. Therefore, a significant shortening of the development period can also be achieved.

[0021] This is extremely effective for an in-vehicle electric compressor in which a high-voltage circuit and a low-voltage circuit are arranged on the inverter substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic cross-sectional view of an in-vehicle electric compressor according to an embodiment of the present invention. Figure 2 is conceived Figure 1 is a block diagram of the electrical circuit of the in-vehicle electric compressor in the case of EMI testing. Figure 3 is Figure 1 is a top view of the inverter substrate of the in-vehicle electric compressor. Figure 4 is Figure 3An enlarged view of the inductor portion. Figure 5 It is an equivalent circuit diagram of a Y capacitor connected in series with an inductor. Figure 6 It is an equivalent circuit diagram of a single Y capacitor. Figure 7 It is to illustrate Figure 5 and Figure 6 A diagram showing the impedance characteristics in the case of. Detailed implementation mode

[0023] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, refer to Figure 1 This describes an in-vehicle electric compressor (so-called inverter-integrated in-vehicle electric compressor) 1 to which the embodiments of the present invention are applied. In addition, the in-vehicle electric compressor 1 of the embodiment constitutes a part of the refrigerant circuit of a vehicle air conditioning device mounted on an electric vehicle such as a hybrid vehicle or an electric vehicle.

[0024] (1) Structure of the in-vehicle electric compressor 1 In Figure 1 Inside the cylindrical box body 2 made of metal (aluminum with a predetermined thickness in the embodiment) of the in-vehicle electric compressor 1, it is divided into a compression mechanism housing portion 4 and an inverter housing portion 6 by a partition wall 3 intersecting the axial direction of the box body 2. Inside the compression mechanism housing portion 4, for example, a scroll-type compression mechanism 7 and a motor 8 for driving the compression mechanism 7 are housed.

[0025] In this case, the motor 8 of the embodiment is an IPMSM (Interior Permanent Magnet Synchronous Motor: interior permanent magnet synchronous motor) composed of a stator 9 fixed to the box body 2 and a rotor 11 rotating inside the stator 9.

[0026] A bearing portion 12 is formed at the central portion of the partition wall 3 on the side of the compression mechanism housing portion 4. One end of the drive shaft 13 of the rotor 11 is supported by the bearing portion 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 partition wall 3 at the position of the box body 2 corresponding to the compression mechanism housing portion 4. If the rotor 11 (drive shaft 13) of the motor 8 rotates to drive the compression mechanism 7, the low-temperature refrigerant as the working fluid flows into the compression mechanism housing portion 4 of the box body 2 from the intake port 14 and is sucked and compressed by the compression mechanism 7.

[0027] Moreover, the refrigerant that is compressed by the compression mechanism 7 to become high-temperature and high-pressure is discharged from an outlet (not shown) to the refrigerant circuit outside the box body 2. In addition, since the low-temperature refrigerant flowing in from the suction port 14 passes near the partition wall 3 and around the motor 8 and is attracted by the compression mechanism 7, the motor 8 and the partition wall 3 are also cooled.

[0028] Moreover, an inverter device 16 that drives and controls the motor 8 is housed in the inverter housing portion 6 that is separated from the compression mechanism housing portion 4 by using the partition wall 3. In this case, the inverter device 16 is configured to supply power to the motor 8 via a sealed terminal and a wire that penetrate the partition wall 3.

[0029] (2) Structure of the inverter device 16 The inverter device 16 of the embodiment includes an inverter substrate 17, six switching elements 18 wired on one side of the inverter substrate 17, a control device 36 disposed on the other side of the inverter substrate 17, and a high-voltage connector, a low-voltage connector, etc. (not shown). In the embodiment, each switching element 18 is formed of an insulated gate bipolar transistor (IGBT) in which an MOS structure is assembled to the gate portion.

[0030] In this case, each switching element 18 forms a three-phase inverter circuit 34 described later, and the terminal portion 22 of each switching element 18 is connected to the inverter substrate 17. Moreover, the assembled inverter device 16 is housed in the inverter housing portion 6 and mounted on the partition wall 3 in a state where the one side where the respective switching elements 18 are located becomes the partition wall 3 side, and is closed by a cover 23. In this case, the inverter substrate 17 is fixed to the partition wall 3 by means of a boss portion 24 that stands up from the partition wall 3.

[0031] In the state where the inverter device 16 is thus mounted on the partition wall 3, each switching element 18 is in direct contact with the partition wall 3 or via a predetermined insulating heat-conducting member, and a heat exchange relationship is formed with the partition wall 3 of the box body 2. And as described above, the partition wall 3 is cooled by the refrigerant sucked into the compression mechanism housing portion 4. Therefore, each switching element 18 forms a heat exchange relationship with the sucked refrigerant via the partition wall 3 and is cooled by the refrigerant sucked into the compression mechanism housing portion 4 through the thickness of the partition wall 3. Each switching element 18 itself is in a form of dissipating heat to the refrigerant via the partition wall 3. That is, the box body 2 (partition wall 3) serves as a radiator for each switching element 18.

[0032] (3) Circuit structure of the inverter device 16 Next, in Figure 2In this case, the inverter device 16 of the present invention includes: the aforementioned inverter circuit 34 composed of IGBTs, which is used to operate the motor 8; the aforementioned control device 36, which is composed of a microcomputer, a driver, etc. for controlling the inverter circuit 34; a high-voltage circuit filter (EMI filter) 37; a low-voltage power supply 38; and a LIN transceiver 39, etc. They are wired on the aforementioned inverter substrate 17 and housed in the aforementioned inverter housing portion 6.

[0033] In addition, the vehicle is equipped with a motor 8 of an in-vehicle electric compressor 1 and a high-voltage battery (high-voltage power supply: in-vehicle battery) 41 of about DC300V for supplying power to a motor for traveling (not shown) to drive. The inverter device 16 is connected to the high-voltage battery 41 through the aforementioned high-voltage connector (not shown).

[0034] In Figure 2 In the case of performing an EMI test on a component (in-vehicle electric compressor unit), 46 is a positive-side high-voltage power line connected to the positive side (+) of the high-voltage battery 41 through a LISN (artificial power network) 48, and 47 is a negative-side high-voltage power line connected to the negative side (-) of the high-voltage battery 41 through a LISN 49. The high-voltage circuit filter 37 is connected to the above-mentioned positive-side high-voltage power line 46 and negative-side high-voltage power line 47. In the case of a vehicle, the LISN 48 and LISN 49 are not connected.

[0035] The high-voltage circuit filter 37 includes: an X capacitor 51 connected between the positive-side high-voltage power line 46 and the negative-side high-voltage power line 47; a common-mode coil 52 inserted into the positive-side high-voltage power line 46 at the subsequent stage of the X capacitor 51; a smoothing capacitor 53 connected between the positive-side high-voltage power line 46 and the negative-side high-voltage power line 47 at the subsequent stage of the common-mode coil 52; a common-mode coil 54 connected to the subsequent stage of the smoothing capacitor 53; a plurality of Y capacitors (represented by 56) respectively connected between the positive-side high-voltage power line 46 and the negative-side high-voltage power line 47 and the housing 2 at the subsequent stage of the common-mode coil 54; and an inductor 57 connected in series with one of the Y capacitors 56 in the embodiment.

[0036] The above-mentioned X capacitor 51 is a capacitor for reducing common-mode noise, and the Y capacitor 56 is a capacitor for reducing common-mode noise. In addition, the smoothing capacitor 53 is a capacitor that smooths the voltage ripple and short-circuits high frequencies as a starting point for impedance balance. The high-voltage circuit filter 37 is connected between the high-voltage battery 41 and the inverter circuit 34, and plays a role in reducing the EMI noise generated by the switching of the inverter circuit 34.

[0037] In addition, the function of the inductor 57 will be described in detail later. Further, the inverter circuit 34 is wired and connected to the motor 8 by using the bus bar 43, and the housing 2 is grounded (conducted) to the vehicle body 42 (ground surface).

[0038] The high-voltage circuit 58 of the inverter device 16 is composed of the above-mentioned positive-side high-voltage power line 46, negative-side high-voltage power line 47, high-voltage circuit filter 37, and inverter circuit 34. The high-voltage circuit filter 37 is composed of an X capacitor 51, a common-mode coil 52, a smoothing capacitor 53, a common-mode coil 54, a Y capacitor 56, and an inductor 57. In addition, the low-voltage circuit 59 of the inverter device 16 is composed of a control device 36, a low-voltage power supply 38, a LIN transceiver 39, etc. Moreover, in the embodiment, the above-mentioned high-voltage circuit 58 and low-voltage circuit 59 are arranged in a state close to the same inverter substrate 17.

[0039] (4) Structure of the inverter substrate 17 Next, Figure 3 shows a top view of the inverter substrate 17, Figure 4 shows Figure 3 an enlarged view of the inductor 57 part. The inverter substrate 17 is a printed substrate on which the respective elements of the aforementioned inverter device 16 are wired. However, since the Y capacitor 56, which is effective for high-frequency noise as described above, is strongly affected by the location (impedance characteristics) in the inverter substrate 17, on the inverter substrate 17, mounting patterns 61 (including 61A) are respectively arranged in advance at a plurality of locations assumed to be effective as the mounting positions of the Y capacitor 56.

[0040] In the embodiment, the mounting patterns 61 of the Y capacitor 56 are formed at seven locations on the inverter substrate 17 considered to be effective, and the Y capacitor 56 is respectively connected to each mounting pattern 61. In the case of the embodiment, one Y capacitor 56 is composed of a ceramic capacitor bank in which a plurality of surface-mounted ceramic capacitors 63 are connected in series in order to ensure sufficient withstand voltage for the purpose of ensuring vehicle safety. In addition, the surface-mounted ceramic capacitors 63 are actually used by connecting two to four in series. In the present embodiment, one Y capacitor 56 is composed of a ceramic capacitor bank in which three surface-mounted ceramic capacitors 63 are connected in series.

[0041] Moreover, in the embodiment, the inductor 57 is connected in series with the Y capacitor 56, and the Y capacitor 56 is connected to the one in Figure 3 , Figure 4The mounting pattern represented by 61A in the figure. In the case of the embodiment, the inductor 57 uses a surface-mounted chip inductor. Additionally, a chip bead can also be used as the inductor 57. Furthermore, it is not limited to one location, and the inductor 57 can be connected in series with multiple Y capacitors 56, or the inductor 57 can be separately connected in series with all the Y capacitors 56 according to the situation of the effect.

[0042] (5) Operation of the inverter device 16 The inverter circuit 34 is composed of the aforementioned six switching elements 18 connected in a three-phase bridge configuration, and each switching element 18 is controlled by a gate drive signal generated by a gate driver included in the control device 36. The control device 36 is composed of a microcomputer (CPU) and a gate driver, and performs PWM modulation by switching each switching element 18 of the inverter circuit 34, thereby converting the DC voltage of the high-voltage battery 41 into an AC voltage of a predetermined frequency and applying it to the motor 8.

[0043] (6) Noise path of the inverter device 16 Here, since the switching elements 18 constituting the inverter circuit 34 generate surge voltages (vibration voltages) during switching, the inverter circuit 34, the control device 36, the low-voltage power supply 38, and the LIN transceiver 39 become noise sources 60. The noise current generated from this noise source 60 flows out to the housing 2 via the inverter substrate 17, the bus bar 43, and the stray capacitance between the motor 8 and the housing 2 ( Figure 2 the noise current inflow path represented by 62 in the figure). Since it becomes a common-mode noise current and flows from the housing 2 to the vehicle body 42 ( Figure 2 represented by the shaded arrow in the figure), it flows to the LISN 48, 49 during the EMI test of the components, so it is detected as noise. Subsequently, the noise returns (noise) from the wiring to the inverter substrate 17. Figure 2 The dotted arrow in the figure represents the radiated noise generated by the common-mode noise current, and the dash-dotted arrow represents the normal-mode noise current. Additionally, radiated noise is generated regardless of whether it is a component or a vehicle.

[0044] (7) Functions of the Y capacitor 56 and the inductor 57 A part of the common-mode noise current flowing out from the above-mentioned noise source 60 returns (recycles) to the noise source 60 via the Y capacitor 56 and the inductor 57 (through the solid arrow of the Y capacitor 56 in Figure 2 the figure), so the common-mode noise current is correspondingly reduced.

[0045] Here, Figures 5 to 7 is used to illustrate the difference in the noise improvement effect in the case of a single Y capacitor 56 and the case where the inductor 57 is connected in series with the Y capacitor 56 as in the present invention. Figure 5 is as in Figure 4As shown in FIG. 1 , an equivalent circuit diagram in which the inductor 57 and the Y capacitor 56 connected to the mounting pattern 61A are connected in series is shown in FIG. Figure 6 6 is an equivalent circuit diagram of a single Y capacitor 56 without connecting the inductor 57 . In each diagram, 65 is the capacitance of the Y capacitor 56 , 64 is the parasitic series resistance of the Y capacitor 56 , and 66 is the parasitic series inductance of the Y capacitor 56 .

[0046] Moreover, in Figure 7 In the above example, L1 indicates Figure 5 The impedance characteristics of the case, L2 represents Figure 6 As described above, in order to ensure sufficient withstand voltage for the purpose of ensuring vehicle safety, one Y capacitor 56 is composed of a ceramic capacitor group in which three surface mount ceramic capacitors 63 are connected in series. Therefore, the Y capacitor 56 single body ( Figure 6 ) the resultant capacitance is reduced, e.g. Figure 7 As shown by L2 in the middle, the resonance frequency (the frequency at which the impedance becomes minimum) becomes higher and is located at about 150 MHz in the embodiment.

[0047] Here, the lower the impedance, the better the improvement characteristics of the Y capacitor against the common mode noise. On the other hand, the noise current generated when the switching element 18 of the inverter circuit 34 is switched is 30MHz to 50MHz. Figure 6 In the case of the Y capacitor 56 shown as a single unit, in the frequency band of 30 MHz to 50 MHz ( Figure 7 In the range indicated by X1 in the figure, the impedance is not minimized and sufficient noise improvement characteristics cannot be expected.

[0048] On the other hand, Figure 5 When the inductor 57 and the Y capacitor 56 are connected in series as shown, the impedance characteristics are as follows: Figure 7 In the present invention, since the inductor 57 and the Y capacitor 56 are connected in series, the resonant frequency is shifted to a lower direction. In addition, in the embodiment, the resonant frequency is configured to be in the frequency band of 30MHz to 50MHz ( Figure 7 The impedance characteristics in this frequency band are greatly improved by shifting the X1 in the frequency band.

[0049] Thus, the switching surge noise in the VHF band generated when the motor 8 is driven is effectively returned to the inverter circuit 34 of the noise source 60 through the Y capacitor 56 and the inductor 57 and recovered, thereby preventing the noise from flowing to the outside.

[0050] In addition, since the resonance frequency shifts downward in the case of the series connection of the inductor 57 (L1), the impedance becomes higher at frequencies exceeding 50 MHz (especially above 100 MHz) compared to the case of the Y-capacitor 56 alone (L2) (L1 > L2: Figure 7 ). The noise above 100 MHz is mainly the noise generated from the control device 36. However, the impedance of the path through which the noise current passes from the control device 36 to the box body 2 is very high, and there is no need for the Y-capacitor to recover the noise. In addition, as shown in the embodiment, since the inverter substrate 17 is housed in the inverter housing portion 6 of the box body 2 made of thick aluminum and is shielded, the risk of the radiation noise directly generated from the control device 36 leaking to the outside becomes almost negligible.

[0051] According to the present invention described in detail above, the inverter substrate 17 is mounted with an inverter circuit 34 that converts the DC voltage from the high-voltage battery 41 into an AC voltage and applies it to the motor 8. The in-vehicle electric compressor 1 having the inverter substrate 17 in the aluminum box body 2 includes: a common-mode coil 54 inserted into the high-voltage power line 46 on the positive electrode side and the high-voltage power line 47 on the negative electrode side from the high-voltage battery 41; a Y-capacitor 56 connected between each power line 46, 47 and the box body 2; and an inductor 57 connected in series with the Y-capacitor 25. Therefore, without increasing the capacitance of the Y-capacitor 56, the resonance frequency of the series circuit of the Y-capacitor 56 and the inductor 57 can be shifted to the low-frequency side.

[0052] Thus, even in the case where the Y-capacitor 56 is composed of a series ceramic capacitor bank in which surface-mounted ceramic capacitors 63 are connected in series and the combined capacitance is reduced and the resonance frequency becomes higher, the switching surge noise of 30 MHz to 50 MHz generated when driving the motor 8 of the in-vehicle electric compressor 1 can be effectively returned to the inverter circuit 34 as the noise source through the Y-capacitor 56 and the inductor 57 and recovered, suppressing its outflow to the outside, and the EMI can be improved.

[0053] In addition, since the radiation noise generated from the control device 36 is shielded by the aluminum box body 2 housing the inverter substrate 17, there are no particular problems.

[0054] In addition, there is no need to further connect the series ceramic capacitor bank in parallel in order to increase the capacitance of the Y-capacitor 56. As long as a cheap inductor 57 composed of a chip inductor or a chip bead is connected, the cost can be significantly reduced and the in-vehicle electric compressor 1 can be miniaturized.

[0055] In addition, when arranging and mounting a plurality of mounting patterns 61 of Y capacitors 56 on the inverter substrate 17, since EMI can be improved by connecting an inductor 57 in series with at least one of the Y capacitors 56, there is no need for the operation of sorting and combining them after confirming the mounting pattern 61 effective for EMI during trial production as in the past, and the reduction in the reproducibility of EMI generated during the sorting and combining of the non-mounted patterns is also eliminated. Therefore, a significant shortening of the development period can also be achieved.

[0056] In the in-vehicle electric compressor 1 in which the high-voltage circuit 58 and the low-voltage circuit 59 are arranged close to the inverter substrate 17 as in the embodiment, since the influence of noise from the high-voltage circuit 58 on the low-voltage circuit 59 can be significantly improved, it is extremely effective.

[0057] In addition, the present invention is not limited to the specific structures and numerical values shown in the embodiments, and various changes can be made without departing from the gist of the present invention. Explanation of reference numerals

[0058] 1 In-vehicle electric compressor 2 Housing 3 Partition wall 6 Inverter housing part 8 Motor 16 Inverter device 17 Inverter substrate 18 Switching element 34 Inverter circuit 36 Control device 37 High-voltage circuit filter 41 High-voltage battery (in-vehicle battery) 46 Positive-side high-voltage power supply line (high-voltage power supply line) 47 Negative-side high-voltage power supply line (high-voltage power supply line) 54 Common-mode coil 56 Y capacitor 57 Inductor 58 High-voltage circuit 59 Low-voltage circuit 69 Noise source 61 (61A) Mounting pattern 63 Ceramic capacitor.

Claims

1. An in - vehicle electric compressor includes an inverter substrate in a metal housing. The inverter substrate is equipped with an inverter circuit that converts direct current from an in - vehicle battery into alternating current and applies it to a motor. It is characterized in that, Comprising: A common-mode coil inserted into the high-voltage power line from the vehicle-mounted battery; A Y capacitor connected between the high-voltage power line and the box body; And An inductor connected in series with the Y capacitor.

2. The in-vehicle electric compressor according to claim 1, characterized in that The Y capacitor is composed of a ceramic capacitor bank in which a plurality of surface-mounted ceramic capacitors are connected in series, The inductor is composed of a surface-mounted chip inductor or a chip bead.

3. The in-vehicle electric compressor according to claim 1, characterized in that The inductor shifts the resonance frequency of the series circuit of the inductor and the Y capacitor in a lower direction.

4. The in-vehicle electric compressor according to claim 1, characterized in that On the inverter substrate, mounting patterns of the Y capacitor are arranged at multiple positions, and The inductor is connected to at least one of the Y capacitors.

5. The in-vehicle electric compressor according to any one of claims 1 to 4, characterized in that A high-voltage circuit and a low-voltage circuit are arranged on the inverter substrate. The high-voltage circuit includes the high-voltage power line from the vehicle-mounted battery, the Y capacitor and the inductor, and the low-voltage circuit includes a control device for controlling the inverter circuit.

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