In-vehicle converter device and in-vehicle fluid machine

Abstract

The present invention relates to an in-vehicle converter device and an in-vehicle fluid machine, and can suppress the relay from being in an on state when the capacitor in the filter circuit is charged. The in-vehicle converter device (30) drives an in-vehicle electric motor using an in-vehicle power storage device (104). The in-vehicle converter device (30) includes input terminals (31, 32), a converter circuit (50), a filter circuit (60) having a filter capacitor (63), a drive circuit (71) and a compressor ECU (72) as control circuits, and a low-voltage power supply circuit (80). Here, when low DC power (P2) is supplied from the low-voltage power supply circuit (80) to the drive circuit (71) and the compressor ECU (72) in a situation where high DC power (P1) is not input to the input terminals (31, 32), the U-phase lower-arm switching element (Qu2) is set to an on state.

Description

Technical Field

[0001] The present invention relates to an in-vehicle converter device and an in-vehicle fluid machine. Background Art

[0002] As shown in, for example, Patent Document 1, an in-vehicle converter device that converts DC power into AC power using an in-vehicle power supply is known. The in-vehicle converter device described in Patent Document 1 includes a converter circuit, a smoothing capacitor that is a capacitor serving as a filter circuit provided between the converter circuit and a high-voltage power supply serving as an in-vehicle power supply, a relay provided between the smoothing capacitor and the high-voltage power supply, and a control device serving as a control circuit.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-046870 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Here, the inventors of the present application have found that sometimes the capacitor of the filter circuit provided in the in-vehicle converter device is charged before the relay for supplying DC power from the in-vehicle power supply to the in-vehicle converter device becomes in the ON state. And the inventors of the present application have found that since the relay becomes in the ON state in a state where the capacitor of the filter circuit is charged, a failure occurs during the operation of the relay.

[0008] The present invention has been completed in view of the above circumstances, and an object thereof is to provide an in-vehicle converter device that can suppress the relay from becoming in the ON state in a state where the capacitor of the filter circuit is charged, and an in-vehicle fluid machine having the in-vehicle converter device.

[0009] Means for Solving the Problems

[0010] The in-vehicle converter device that achieves the above object drives an in-vehicle electric motor using an in-vehicle power supply. The in-vehicle converter device includes: an input terminal connected to the in-vehicle power supply via a relay; a filter circuit that reduces noise contained in the DC power input from the input terminal and has a capacitor; a converter circuit that includes an upper-arm switching element and a lower-arm switching element connected in series to each other through a connection line and converts the DC power input from the filter circuit into AC power; a control circuit that controls the upper-arm switching element and the lower-arm switching element; an upper-arm ground line connecting the control circuit and the connection line; and a low-voltage power supply circuit that supplies DC power to the control circuit without passing through the relay and the input terminal. When the control circuit supplies DC power from the low-voltage power supply circuit in a state where no DC power is input to the input terminal (DC power is not being input to the input terminal), the lower-arm switching element is set to the on state.

[0011] As a reason for the capacitor of the filter circuit being charged before the relay becomes in the on state, the inventor of the present application found a leakage current leaking from the control circuit. Specifically, the inventor of the present application found that when DC power is supplied to the control circuit, a leakage current is generated in the control circuit, and due to this leakage current, the capacitor of the filter circuit is charged before the relay becomes in the on state.

[0012] Based on this finding, in this configuration, in a state where the relay is in the off state, that is, in a state where no DC power is input to the input terminal, when DC power is supplied to the control circuit, the lower-arm switching element becomes in the on state. As a result, the leakage current leaking from the control circuit flows through the upper-arm ground line and the lower-arm switching element, thereby suppressing the charging of the capacitor of the filter circuit. Therefore, it is possible to suppress the relay from becoming in the on state in a state where the capacitor of the filter circuit is charged.

[0013] Regarding the above in-vehicle converter device, it is possible that the control circuit switches the lower-arm switching element from the on state to the off state based on DC power being input to the input terminal.

[0014] According to this configuration, when the relay becomes in the on state and DC power is input to the input terminal, the lower-arm switching element becomes in the off state. As a result, it is possible to smoothly start the control of the in-vehicle electric motor. In addition, after the relay becomes in the on state, even if the capacitor of the filter circuit is charged, it is difficult for a failure to occur during the operation of the relay. Therefore, it is possible to suppress the influence on the relay and smoothly start the control of the in-vehicle electric motor.

[0015] Regarding the above-mentioned in-vehicle converter device, the filter circuit may have a coil; the filter circuit may have a low-pass filter circuit including the coil and the capacitor.

[0016] According to this configuration, it is possible to reduce the common-mode noise contained in the DC power input to the input terminal. In addition, according to this configuration, as described above, it is possible to suppress the relay from being turned on when the capacitor in the filter circuit is charged. Therefore, for example, it is not necessary to reduce the capacitance of the capacitor in the filter circuit in order to reduce the influence on the relay when the relay is turned on. Therefore, the capacitance of the capacitor in the filter circuit can be freely set without considering the influence on the relay, and noise reduction or stabilization of the output voltage can be appropriately achieved.

[0017] The in-vehicle fluid machine that achieves the above object has the in-vehicle electric motor and the above-mentioned in-vehicle converter device.

[0018] The above-mentioned in-vehicle fluid machine may be an in-vehicle electric compressor having a compression part driven by the in-vehicle electric motor.

[0019] Advantages of the Invention

[0020] According to the present invention, it is possible to suppress the relay from being turned on when the capacitor in the filter circuit is charged. Description of the Drawings

[0021] Figure 1 It is a block diagram showing an outline of an in-vehicle electric compressor.

[0022] Figure 2 It is a block diagram showing the electrical configuration of an in-vehicle converter device.

[0023] Figure 3 It is a circuit diagram for explaining the filter circuit, the converter circuit, and the flow of leakage current.

[0024] Reference Signs

[0025] 10... In-vehicle electric compressor (in-vehicle fluid machine), 11... In-vehicle electric motor, 12... Compression part, 30... In-vehicle converter device, 31, 32... Input terminals, 50... Converter circuit, 60... Filter circuit, 62... Common-mode coil (coil), 71... Drive circuit, 72... Compressor ECU, 80... Low-voltage power supply circuit, 91... Upper-arm ground wire, 92... Lower-arm ground wire, 111, 112, 114, 115... Relays, LNu, LNv, LNw... Connection lines, Qu1, Qv1, Qw1... Upper-arm switching elements, Qu2, Qv2, Qw2... Lower-arm switching elements, P1... High DC power (DC power of the first voltage), P2... Low DC power (DC power of the second voltage). Detailed Embodiment

[0026] Hereinafter, an embodiment of an in-vehicle converter device and an in-vehicle fluid machine having the in-vehicle converter device will be described. In addition, the following description shows an example, and the in-vehicle converter device and the in-vehicle fluid machine are not limited to the content of this embodiment.

[0027] In this embodiment, the in-vehicle fluid machine is an in-vehicle electric compressor for an in-vehicle air conditioner. An overview of the in-vehicle air conditioner and the in-vehicle electric compressor will be described.

[0028] As Figure 1 shown, the in-vehicle air conditioner 101 mounted on the vehicle 100 includes an in-vehicle electric compressor 10 and an external refrigerant circuit 102 that supplies refrigerant as a fluid to the in-vehicle electric compressor 10.

[0029] The external refrigerant circuit 102 has, for example, a heat exchanger and an expansion valve. The in-vehicle air conditioner 101 compresses the refrigerant using the in-vehicle electric compressor 10 and performs heat exchange and expansion of the refrigerant using the external refrigerant circuit 102, thereby performing cooling and heating inside the vehicle.

[0030] The in-vehicle air conditioner 101 has an air conditioner ECU 103 that controls the entire in-vehicle air conditioner 101. The air conditioner ECU 103 is configured to be able to grasp the vehicle interior temperature, the set temperature of the vehicle air conditioner, etc., and send various commands such as a commanded rotational speed to the in-vehicle electric compressor 10 based on these parameters.

[0031] The vehicle 100 has an in-vehicle power storage device 104 as an in-vehicle power source. The in-vehicle power storage device 104 can be any as long as it can perform charging and discharging of DC power, for example, a secondary battery, an electric double layer capacitor, etc. The in-vehicle power storage device 104 outputs high DC power P1. The high DC power P1 is the discharge power of the in-vehicle power storage device 104.

[0032] The in-vehicle electric compressor 10 includes an in-vehicle electric motor 11, a compression part 12 driven by the in-vehicle electric motor 11, and an in-vehicle converter device 30 that uses the in-vehicle power storage device 104 to drive the in-vehicle electric motor 11.

[0033] The in-vehicle electric motor 11 has a rotating shaft 21, a rotor 22 fixed to the rotating shaft 21, a stator 23 disposed opposite to the rotor 22, and three-phase coils 24u, 24v, 24w wound around the stator 23. The rotor 22 includes a permanent magnet 22a. Specifically, the permanent magnet 22a is embedded in the rotor 22. As Figure 2As shown, the three-phase coils 24u, 24v, and 24w are, for example, Y-connected. By energizing the three-phase coils 24u, 24v, and 24w in a predetermined pattern, the rotor 22 and the rotating shaft 21 rotate. That is, the in-vehicle electric motor 11 of the present embodiment is a three-phase motor.

[0034] In addition, the wiring method of the three-phase coils 24u, 24v, and 24w is not limited to Y-connection and is arbitrary. For example, it can be delta connection. Also, the rotational speed and acceleration of the in-vehicle electric motor 11 refer to the rotational speed and acceleration of the rotor 22.

[0035] The compression unit 12 is driven by the in-vehicle electric motor 11 to compress a fluid (refrigerant in the present embodiment). Specifically, the compression unit 12 rotates the rotating shaft 21 to compress the suction refrigerant supplied from the external refrigerant circuit 102 and discharge the compressed refrigerant. The specific configuration of the compression unit 12 can be any of a scroll type, a piston type, a vane type, etc.

[0036] As Figure 2 shown, the in-vehicle converter device 30 has input terminals 31, 32 and output terminals 33, 34, 35.

[0037] The input terminals 31, 32 are used to connect the in-vehicle converter device 30 and the in-vehicle power storage device 104. In the present embodiment, the input terminals 31, 32 are connected to the in-vehicle power storage device 104 via relays 111, 112, 114, 115. Specifically, the vehicle 100 has vehicle power supply lines LN11, LN12 connecting the input terminals 31, 32 and the in-vehicle power storage device 104. Relays 111, 114 are provided on the first vehicle power supply line LN11. Relays 112, 115 are provided on the second vehicle power supply line LN12. In addition, in the present embodiment, the relays 111, 112, 114, 115 are provided outside the in-vehicle converter device 30.

[0038] According to this configuration, when the relays 111, 112, 114, 115 are in the ON state, the high DC power P1 output from the in-vehicle power storage device 104 is input to the input terminals 31, 32. On the other hand, when the relays 111, 112, 114, 115 are in the OFF state, the high DC power P1 is not input to the input terminals 31, 32. In the present embodiment, the relays 111, 112, 114, 115 are in the OFF state in the initial state.

[0039] In the present embodiment, the vehicle 100 has a smoothing capacitor 113 connected to the in-vehicle power storage device 104. The smoothing capacitor 113 is connected to the two vehicle power supply lines LN11 and LN12. The smoothing capacitor 113 is disposed between the relays 111, 112 and the relays 114, 115. In this case, it can also be said that the relays 111, 112 are disposed between the in-vehicle power storage device 104 and the smoothing capacitor 113, and the relays 114, 115 are disposed between the smoothing capacitor 113 and the input terminals 31, 32. In addition, for the sake of convenience of explanation, in the following description, the relays 111, 112 are also referred to as main relays 111, 112, and the relays 114, 115 are also referred to as sub-relays 114, 115.

[0040] The output terminals 33, 34, 35 are for connecting the in-vehicle converter device 30 and the in-vehicle electric motor 11. In the present embodiment, the output terminals 33, 34, 35 are connected to the three-phase coils 24u, 24v, 24w of the in-vehicle electric motor 11.

[0041] The in-vehicle converter device 30 converts the high DC power P1 input from the input terminals 31, 32 into AC power and outputs the converted AC power from the output terminals 33, 34, 35, thereby driving the in-vehicle electric motor 11 using the in-vehicle power storage device 104.

[0042] As Figure 1 and Figure 2 shown, the in-vehicle converter device 30 includes a positive bus bar 41 and a negative bus bar 42, an inverter circuit 50, a filter circuit 60, and a drive circuit 71 and a compressor ECU 72 as control circuits for controlling the inverter circuit 50.

[0043] As Figure 2 shown, the positive bus bar 41 is connected to the first input terminal 31. The positive bus bar 41 is connected to the positive terminal (+ terminal) of the in-vehicle power storage device 104 via the first input terminal 31, the first sub-relay 114, and the first main relay 111. The negative bus bar 42 is connected to the second input terminal 32. The negative bus bar 42 is connected to the negative terminal (- terminal) of the in-vehicle power storage device 104 via the second input terminal 32, the second sub-relay 115, and the second main relay 112.

[0044] The inverter circuit 50 includes three-phase switching elements Qu1 to Qw2. Specifically, the inverter circuit 50 includes a u-phase switching element Qu1, Qu2 corresponding to the u-phase coil 24u, a v-phase switching element Qv1, Qv2 corresponding to the v-phase coil 24v, and a w-phase switching element Qw1, Qw2 corresponding to the w-phase coil 24w.

[0045] The three-phase switching elements Qu1 to Qw2 are, for example, power switching elements such as IGBTs. The three-phase switching elements Qu1 to Qw2 have a gate terminal as a control terminal, and a collector terminal and an emitter terminal through which the converter current flows. The converter current is the current flowing through the three-phase coils 24u, 24v, and 24w. In addition, the three-phase switching elements Qu1 to Qw2 have freewheeling diodes Du1 to Dw2.

[0046] However, the three-phase switching elements Qu1 to Qw2 are not limited to IGBTs and can be arbitrary. For example, they can be MOSFETs. In this case, the freewheeling diodes Du1 to Dw2 can be formed by the body diodes of the three-phase switching elements Qu1 to Qw2.

[0047] Each of the u-phase switching elements Qu1 and Qu2 is connected in series with each other via the u-phase connection line LNu. The u-phase connection line LNu is connected to the u-phase coil 24u via the u-phase output terminal 33.

[0048] The u-phase upper-arm switching element Qu1 is connected to the positive busbar 41, and the u-phase lower-arm switching element Qu2 is connected to the negative busbar 42. Specifically, the collector terminal of the u-phase upper-arm switching element Qu1 is connected to the positive busbar 41, and the emitter terminal of the u-phase lower-arm switching element Qu2 is connected to the negative busbar 42.

[0049] The anode of the u-phase upper-arm freewheeling diode Du1 is connected to the u-phase connection line LNu, and the cathode of the u-phase upper-arm freewheeling diode Du1 is connected to the positive busbar 41. The anode of the u-phase lower-arm freewheeling diode Du2 is connected to the negative busbar 42, and the cathode of the u-phase lower-arm freewheeling diode Du2 is connected to the u-phase connection line LNu.

[0050] In addition, the connection methods of the other switching elements Qv1, Qv2, Qw1, and Qw2 are the same as those of the u-phase switching elements Qu1 and Qu2 except for the corresponding output terminals. That is, the v-phase upper-arm switching element Qv1 and the v-phase lower-arm switching element Qv2 are connected in series with each other via the v-phase connection line LNv, and the w-phase upper-arm switching element Qw1 and the w-phase lower-arm switching element Qw2 are connected in series with each other via the w-phase connection line LNw.

[0051] As Figure 2 shown, the filter circuit 60 is provided between the input terminals 31 and 32 and the converter circuit 50. The filter circuit 60 reduces the noise contained in the high DC power P1 input from the input terminals 31 and 32. Thus, the DC power with reduced noise by the filter circuit 60 is input to the converter circuit 50. Then, the converter circuit 50 converts the DC power input from the filter circuit 60 into AC power.

[0052] The filter circuit 60 includes, for example, a common-mode coil 61 disposed on the two busbars 41 and 42, a normal-mode coil 62 disposed on at least one of the positive busbar 41 and the negative busbar 42 (the positive busbar 41 in this embodiment), and a filter capacitor 63. In this embodiment, the filter capacitor 63 corresponds to "the capacitor of the filter circuit".

[0053] The filter capacitor 63 is connected to the converter circuit 50 (specifically, the three-phase switching elements Qu1 to Qw2) and the input terminals 31 and 32 via the two busbars 41 and 42, for example.

[0054] In this embodiment, the normal-mode coil 62 and the filter capacitor 63 form a low-pass filter circuit. That is to say, it can be said that the filter circuit 60 of this embodiment has a low-pass filter circuit including the normal-mode coil 62 and the filter capacitor 63. In addition, the filter capacitor 63 of this embodiment is also referred to as an X capacitor.

[0055] Incidentally, the capacitance of the filter capacitor 63 of this embodiment is set such that the resonance frequency of the low-pass filter circuit is a desired value and the voltage of the high DC power P1 can be stabilized. However, this is not limited thereto, and the capacitance of the filter capacitor 63 is arbitrary.

[0056] In addition, the capacitance of the filter capacitor 63 may be smaller than the capacitance of the smoothing capacitor 113, or vice versa. Alternatively, the capacitance of the filter capacitor 63 and the capacitance of the smoothing capacitor 113 may be the same.

[0057] The drive circuit 71 is, for example, a circuit having an IC and a switching element. The drive circuit 71 is a circuit that operates by being supplied with a low DC power P2 having a voltage lower than that of the high DC power P1. The drive circuit 71 drives the three-phase switching elements Qu1 to Qw2 respectively based on an instruction from the compressor ECU 72. The high DC power P1 is also referred to as DC power of the first voltage, and the low DC power P2 is also referred to as DC power of the second voltage lower than the first voltage.

[0058] Specifically, the in-vehicle converter device 30 has gate lines Lgu1 to Lgw2 that connect the gate terminals of the three-phase switching elements Qu1 to Qw2 and the drive circuit 71. The drive circuit 71 applies a gate voltage to the gate terminals of the three-phase switching elements Qu1 to Qw2 via the gate lines Lgu1 to Lgw2, thereby driving the three-phase switching elements Qu1 to Qw2 respectively.

[0059] The compressor ECU 72 is a controller having electronic components such as a CPU and a memory. The compressor ECU 72 controls the drive circuit 71 by outputting various instructions to the drive circuit 71. In addition, the compressor ECU 72 may be implemented by at least one of, for example, one or more dedicated hardware circuits and one or more processors (circuits) operating according to a computer program (software).

[0060] The in-vehicle converter device 30 has a voltage sensor 73 that detects the DC power input to the input terminals 31 and 32. The voltage sensor 73 detects whether high DC power P1 is input to the input terminals 31 and 32 by detecting the voltage applied between the two bus bars 41 and 42. Further, the voltage sensor 73 outputs the detection result of the voltage applied between the two bus bars 41 and 42 to the compressor ECU 72. Thereby, the compressor ECU 72 can grasp whether high DC power P1 is input from the input terminals 31 and 32.

[0061] The compressor ECU 72 is a circuit that operates by being supplied with low DC power P2. The compressor ECU 72 performs PWM control on the converter circuit 50 based on an external command value sent from the air conditioner ECU 103 as an external device and the rotational speed of the in-vehicle electric motor 11, thereby controlling the rotation of the in-vehicle electric motor 11.

[0062] Specifically, the compressor ECU 72 generates PWM signals for the three-phase switching elements Qu1 to Qw2 and outputs the PWM signals to the drive circuit 71. The drive circuit 71 generates gate voltages for the three-phase switching elements Qu1 to Qw2 based on the PWM signals input from the compressor ECU 72, and outputs the gate voltages via the respective gate lines Lgu1 to Lgw2, thereby causing the three-phase switching elements Qu1 to Qw2 to be periodically turned on (ON) / off (OFF).

[0063] As Figure 2 and Figure 3 shown, the in-vehicle converter device 30 has a low-voltage power supply circuit 80 that supplies low DC power P2 to the drive circuit 71 and the compressor ECU 72 as control circuits without passing through the relays 111, 112, 114, 115 and the input terminals 31, 32.

[0064] The low-voltage power supply circuit 80 is connected to the low-voltage power supply EL mounted on the vehicle 100 without passing through the relays 111, 112, 114, 115 and the input terminals 31, 32. The low-voltage power supply circuit 80 supplies the low DC power P2 to the drive circuit 71 and the compressor ECU 72 based on receiving the supply of the low DC power P2 from the low-voltage power supply EL. Thereby, the drive circuit 71 and the compressor ECU 72 operate. In other words, it can be said that the drive circuit 71 and the compressor ECU 72 switch from the stopped state to the operating state (activated state) based on being supplied with the low DC power P2.

[0065] In addition, the timing of receiving the supply of the low DC power P2 from the low-voltage power supply EL is arbitrary. For example, it can be when the power supply of the vehicle 100 is turned on, or when the in-vehicle air conditioner is started.

[0066] Here, Figure 3 , the leakage current Ir flowing between the drive circuit 71 and the converter circuit 50 will be described. For ease of explanation, in Figure 3 , the u-phase upper-arm switching element Qu1 and the u-phase lower-arm switching element Qu2 are shown, and the diagrams of the switching elements of other phases are omitted.

[0067] As Figure 3 shown, in the in-vehicle converter device 30, as the wiring connecting the drive circuit 71 and the converter circuit 50, in addition to the gate lines Lgu1 to Lgw2, there are also the upper-arm ground wire 91 and the lower-arm ground wire 92.

[0068] The upper-arm ground wire 91 is the wiring connecting the u-phase connection line LNu and the drive circuit 71. The drive circuit 71 drives the u-phase upper-arm switching element Qu1 by outputting a potential higher than the potential input to the upper-arm ground wire 91 to the u-phase upper-arm gate line Lgu1.

[0069] The lower-arm ground wire 92 is the wiring connecting the negative bus bar 42 and the drive circuit 71. The drive circuit 71 drives the u-phase lower-arm switching element Qu2 by outputting a potential higher than the potential input to the lower-arm ground wire 92 to the u-phase lower-arm gate line Lgu2.

[0070] Here, as Figure 3 shown, when the low DC power P2 is supplied to the drive circuit 71, sometimes the leakage current Ir flows in the drive circuit 71. For example, in the drive circuit 71, sometimes a leakage path 71a is formed that connects the terminal to which the low DC power P2 is supplied and the terminal connected to the upper-arm ground wire 91 via elements such as switching elements. In this case, the leakage current Ir flows through the leakage path 71a to the upper-arm ground wire 91.

[0071] Here, assuming that the two u-phase switching elements Qu1, Qu2 are in the off state, as Figure 3As shown by the double-dashed line, the leakage current Ir flowing into the upper-arm ground wire 91 will flow toward the u-phase upper-arm return diode Du1, the positive bus bar 41, and the filter capacitor 63. As a result, the filter capacitor 63 may be charged. And if the filter capacitor 63 is charged, a voltage will be generated between the input terminals 31 and 32.

[0072] In this situation, that is, when the filter capacitor 63 is charged, when switching the relays 111, 112, 114, and 115 from the off state to the on state, faults may occur in the operation of the relays 111, 112, 114, and 115 due to various conditions such as the connection method and switching sequence of the relays 111, 112, 114, and 115. For example, if the sub-relays 114 and 115 are switched from the off state to the on state under the condition that the main relays 111 and 112 are in the off state, there is a risk of sparking in at least one of the two sub-relays 114 and 115.

[0073] In contrast, the in-vehicle converter device 30 of the present embodiment is configured not to charge the filter capacitor 63 with the leakage current Ir. Hereinafter, this will be described.

[0074] When the compressor ECU 72 starts operating by being supplied with the low DC power P2, it determines whether the high DC power P1 is input to the input terminals 31 and 32 of the in-vehicle converter device 30 based on the detection result of the voltage sensor 73.

[0075] Moreover, when the compressor ECU 72 determines that the high DC power P1 is not input to the input terminals 31 and 32, it outputs an instruction to set the u-phase lower-arm switching element Qu2 to the on state to the drive circuit 71. The drive circuit 71 sets the u-phase lower-arm switching element Qu2 to the on state based on this instruction.

[0076] That is to say, the in-vehicle converter device 30 of the present embodiment sets only the u-phase lower-arm switching element Qu2 to the on state and electrically connects the drive circuit 71 to the negative bus bar 42 via the upper-arm ground wire 91 when the low DC power P2 is supplied to the drive circuit 71 in the situation where the high DC power P1 is not input to the input terminals 31 and 32.

[0077] Then, based on the high DC power P1 detected by the voltage sensor 73, the compressor ECU 72 outputs an instruction to set the lower-arm switch element Qu2 of the u-phase to the off state to the drive circuit 71. Based on this instruction, the drive circuit 71 switches the lower-arm switch element Qu2 of the u-phase from the on state to the off state. That is, in the present embodiment, the drive circuit 71 and the compressor ECU 72 switch the lower-arm switch element Qu2 of the u-phase from the on state to the off state based on the input of the high DC power P1 to the input terminals 31 and 32. Then, the compressor ECU 72 starts the control (PWM control) for driving the in-vehicle electric motor 11 based on an instruction from the air conditioner ECU 103.

[0078] In addition, similarly to the u-phase, the in-vehicle converter device 30 has an upper-arm ground wire connecting the drive circuit 71 and the v-phase connection line LNv, and an upper-arm ground wire connecting the drive circuit 71 and the w-phase connection line LNw. The drive circuit 71 and the compressor ECU 72 perform the same control on the v-phase switch elements Qv1 and Qv2 and the w-phase switch elements Qw1 and Qw2 as on the u-phase switch elements Qu1 and Qu2. That is, when the low DC power P2 is supplied from the low-voltage power supply circuit 80 in a situation where the high DC power P1 is not input to the input terminals 31 and 32, the drive circuit 71 and the compressor ECU 72 set the lower-arm switch elements Qu2, Qv2, and Qw2 to the on state.

[0079] Next, the operation of the present embodiment will be described.

[0080] In a situation where the high DC power P1 is not input to the input terminals 31 and 32 and the low DC power P2 is supplied to the drive circuit 71, the lower-arm switch element Qu2 of the u-phase becomes the on state. As a result, as shown by the solid line in Figure 3 , the leakage current Ir flows through the lower-arm switch element Qu2 of the u-phase instead of the upper-arm freewheeling diode Du1 of the u-phase, so that the leakage current Ir does not flow to the filter capacitor 63. The same applies to the v-phase and the w-phase. Therefore, it is difficult to charge the filter capacitor 63.

[0081] According to the present embodiment described in detail above, the following effects are achieved.

[0082] (1) The in-vehicle converter device 30 drives the in-vehicle electric motor 11 using the in-vehicle storage device 104 as an in-vehicle power source. The in-vehicle converter device 30 has input terminals 31 and 32, a converter circuit 50, a filter circuit 60, and a drive circuit 71 and a compressor ECU 72 as control circuits.

[0083] The input terminals 31 and 32 are connected to the in-vehicle storage battery 104 via relays 111, 112, 114, and 115. The filter circuit 60 is a circuit that reduces the noise contained in the DC power (specifically, the high DC power P1) input from the input terminals 31 and 32, and includes a filter capacitor 63. The converter circuit 50 has upper-arm switching elements Qu1, Qv1, Qw1 and lower-arm switching elements Qu2, Qv2, Qw2 that are connected in series with each other via connection lines LNu, LNv, and LNw, and converts the high DC power P1 input from the filter circuit 60 into AC power. The drive circuit 71 and the compressor ECU 72 control the three-phase switching elements Qu1 to Qw2.

[0084] The in-vehicle converter device 30 has an upper-arm ground wire 91 that connects the drive circuit 71, which is a control circuit, and the u-phase connection line LNu. Also, the in-vehicle converter device 30 has a low-voltage power supply circuit 80 that supplies low DC power P2 to the drive circuit 71 and the compressor ECU 72 without passing through the relays 111, 112, 114, 115 and the input terminals 31, 32.

[0085] In this configuration, when the low DC power P2 is supplied from the low-voltage power supply circuit 80 to the drive circuit 71 and the compressor ECU 72 in a state where the high DC power P1 is not input to the input terminals 31 and 32, the lower-arm switching elements Qu2, Qv2, and Qw2 are set to the ON state.

[0086] According to this configuration, when the high DC power P1 is not input to the input terminals 31 and 32 and the low DC power P2 is supplied to the drive circuit 71, the lower-arm switching elements Qu2, Qv2, and Qw2 become the ON state. Thereby, it is possible to suppress the charging of the filter capacitor 63 by the leakage current Ir leaking from the drive circuit 71. Therefore, it is possible to suppress the relays 111, 112, 114, 115 from becoming the ON state when the filter capacitor 63 is already charged.

[0087] In addition, the relays 111, 112, 114, 115 becoming the ON state includes the case where the relays 111, 112, 114, 115 become the ON state in a predetermined order, and the case where at least two of the relays 111, 112, 114, 115 become the ON state simultaneously.

[0088] (2) When the high DC power P1 is input to the input terminals 31 and 32, the drive circuit 71 and the compressor ECU 72 switch the lower-arm switching elements Qu2, Qv2, and Qw2 from the ON state to the OFF state.

[0089] According to this configuration, when the relays 111, 112, 114, and 115 are in the ON state and high DC power P1 is input to the input terminals 31 and 32, the lower-arm switching elements Qu2, Qv2, and Qw2 are in the OFF state. Thereby, it is possible to avoid starting the control (specifically, PWM control) of the in-vehicle electric motor 11 while the lower-arm switching elements Qu2, Qv2, and Qw2 are in the ON state, and the control of the in-vehicle electric motor 11 can be started smoothly. Further, after the relays 111, 112, 114, and 115 become in the ON state, even if the filter capacitor 63 is charged, it is difficult to cause a failure in the operation of the relays 111, 112, 114, and 115. Therefore, it is possible to suppress the influence on the relays 111, 112, 114, and 115 and start the control of the in-vehicle electric motor 11 smoothly.

[0090] (3) The filter circuit 60 includes a common-mode coil 62 as a coil. The filter circuit 60 includes a low-pass filter circuit including the common-mode coil 62 and the filter capacitor 63.

[0091] According to this configuration, it is possible to reduce the common-mode noise included in the high DC power P1 input to the input terminals 31 and 32. Here, the capacitance of the filter capacitor 63 is sometimes set to adjust the resonance frequency of the low-pass filter circuit or stabilize the voltage of the high DC power P1. In this case, due to the capacitance of the filter capacitor 63, when the relays 111, 112, 114, and 115 are in the ON state, the charge accumulated in the filter capacitor 63 sometimes affects the relays 111, 112, 114, and 115.

[0092] In this regard, according to this configuration, as described above, it is possible to suppress the relays 111, 112, 114, and 115 from becoming in the ON state when the filter capacitor 63 is already charged. Thereby, for example, it is not necessary to reduce the capacitance of the filter capacitor 63 in order to reduce the influence on the relays 111, 112, 114, and 115 when the relays 111, 112, 114, and 115 are in the ON state. Therefore, it is possible to freely set the capacitance of the filter capacitor 63 without considering the influence on the relays 111, 112, 114, and 115, and it is possible to appropriately achieve noise reduction or stabilization of the high DC power P1.

[0093] (4) The in-vehicle electric compressor 10 as an in-vehicle fluid machine includes an in-vehicle electric motor 11 and an in-vehicle converter device 30. Thereby, the effect of (1) can be obtained in the in-vehicle electric compressor 10.

[0094] In addition, the above-described embodiment can be changed as follows.

[0095] ○ The drive circuit 71 and the compressor ECU 72 may also be configured to keep the lower-arm switching elements Qu2, Qv2, and Qw2 in the ON state even when a high DC power P1 is input to the input terminals 31 and 32.

[0096] ○ The specific configuration of the filter circuit 60 is arbitrary. For example, the common-mode choke coil 62 may be omitted, or the differential-mode choke coil 61 may be omitted. Additionally, the common-mode choke coil 62 may be provided on both the positive bus bar 41 and the negative bus bar 42.

[0097] The common-mode choke coil 62 may be composed of a dedicated coil or may be formed by the parasitic inductance of wiring or other components.

[0098] Additionally, the filter circuit 60 may have multiple filter capacitors. For example, in addition to the filter capacitor 63 serving as an X capacitor, the filter circuit 60 may also have a Y capacitor.

[0099] ○ The converter circuit 50 is not limited to three phases and may also be two phases.

[0100] ○ The smoothing capacitor 113 may be omitted.

[0101] ○ The relays 111, 112, 114, and 115 are provided outside the in-vehicle converter device 30, but are not limited thereto, and the in-vehicle converter device 30 may have a configuration including the relays 111, 112, 114, and 115.

[0102] ○ The number of relays, the connection method between the relays, and the connection method between the relays and the smoothing capacitor 113 are arbitrary. That is, the specific configuration (e.g., the number and connection method of the relays) of the relays via the in-vehicle power storage device 104 and the input terminals 31 and 32 is arbitrary.

[0103] For example, the main relays 111 and 112 may be omitted. Additionally, for example, the sub-relays 114 and 115 may be omitted and one or more relays connected to the first main relay 111 or the second main relay 112 may be provided separately. Also in this case, due to the connection method of the relays, the order of becoming the ON state, etc., the relay may become the ON state in a state where the filter capacitor 63 is charged, resulting in a malfunction in the operation of the relay.

[0104] ○ The in-vehicle electric compressor 10 is not limited to the configuration for the in-vehicle air conditioner device 101 and may also be a configuration for other devices. For example, when the vehicle 100 is a fuel cell vehicle, the in-vehicle electric compressor 10 may be used for an air supply device that supplies air to the fuel cell. That is, the fluid to be compressed is not limited to the refrigerant and may be air or any other fluid.

[0105] ○ The in-vehicle fluid machine is not limited to the in-vehicle electric compressor 10 having the compression section 12 for compressing the fluid. For example, when the vehicle 100 is a fuel cell vehicle, the in-vehicle fluid machine may be an electric pump device having a pump for supplying hydrogen to the fuel cell and an in-vehicle electric motor for driving the pump.

[0106] ○ The in-vehicle electric motor 11 is not limited to being used for the in-vehicle electric compressor 10 and can be arbitrary as long as it is mounted on the vehicle. For example, the in-vehicle electric motor 11 may be a driving motor for driving the vehicle.

[0107] Next, a preferred example that can be grasped from the above-described embodiments and other examples will be described below.

[0108] (a) It may be configured to have a first input terminal and a second input terminal as input terminals, a positive bus connected to the first input terminal, a negative bus connected to the second input terminal, an upper-arm freewheeling diode connected in parallel with the upper-arm switching element, the upper-arm switching element being connected to the positive bus, the lower-arm switching element being connected to the negative bus, the cathode of the upper-arm freewheeling diode being connected to the positive bus, the anode of the upper-arm freewheeling diode being connected to the connection line, and a capacitor of the filter circuit being connected to the positive bus and the negative bus.

Claims

1. A vehicle-mounted converter device is a vehicle-mounted converter device that drives a vehicle-mounted electric motor using a vehicle-mounted power supply, wherein, It has: An input terminal connected to the vehicle-mounted power supply via a relay; A filter circuit that reduces the noise contained in the DC power input from the input terminal and has a capacitor; An inverter circuit having an upper-arm switching element and a lower-arm switching element connected in series with each other through a connection line, which converts the DC power input from the filter circuit into AC power; A positive bus bar electrically connecting the input terminal, the capacitor, and the upper-arm switching element; A negative bus bar electrically connecting the input terminal, the capacitor, and the lower-arm switching element; A control circuit for controlling the upper-arm switching element and the lower-arm switching element; An upper-arm ground wire connecting the control circuit and the connection line; And A low-voltage power supply circuit that supplies low DC power having a voltage lower than that of the DC power to the control circuit without passing through the relay and the input terminal; When the low DC power is supplied from the low-voltage power supply circuit in a state where the DC power is not input to the input terminal, the control circuit sets only the lower-arm switching element to the on state and electrically connects the control circuit and the negative bus bar through the upper-arm ground wire.

2. The vehicle-mounted inverter device according to claim 1, wherein The control circuit switches the lower-arm switching element from the on state to the off state based on the input of the DC power to the input terminal.

3. The vehicle-mounted inverter device according to claim 1 or 2, wherein The filter circuit has a coil; The filter circuit has a low-pass filter circuit including the coil and the capacitor.

4. The vehicle-mounted inverter device according to claim 1 or 2, wherein It further has an upper-arm freewheeling diode connected in parallel with the upper-arm switching element; The input terminal has a first input terminal and a second input terminal; The positive bus bar is connected to the first input terminal; The negative bus bar is connected to the second input terminal; The upper-arm switching element is connected to the positive bus bar, the lower-arm switching element is connected to the negative bus bar, the cathode of the upper-arm freewheeling diode is connected to the positive bus bar, and the anode of the upper-arm freewheeling diode is connected to the connection line.

5. The vehicle-mounted inverter device according to claim 3, wherein It further has an upper-arm freewheeling diode connected in parallel with the upper-arm switching element; The input terminal has a first input terminal and a second input terminal; The positive bus bar is connected to the first input terminal; The negative bus bar is connected to the second input terminal; The upper-arm switching element is connected to the positive bus bar, the lower-arm switching element is connected to the negative bus bar, the cathode of the upper-arm freewheeling diode is connected to the positive bus bar, and the anode of the upper-arm freewheeling diode is connected to the connection line.

6. A vehicle-mounted fluid machine having: A vehicle-mounted electric motor; and The vehicle-mounted inverter device according to any one of claims 1 to 5.

7. The vehicle-mounted fluid machine according to claim 6, wherein The in-vehicle fluid machine is an in-vehicle electric compressor having a compression section driven by the in-vehicle electric motor.

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