Current detection device

Abstract

The sensor unit 160 (current detection device) has a first busbar to a third busbar (61b, 62b, 63b) (conductor) arranged in a predetermined direction and a first element to a third element (61a, 62a, 63a). The first busbar forms a current path between the first inverter and the first rotating motor. The second busbar (62b) forms a current path between the second inverter and the second rotating motor. The third busbar (63b) forms a current path between the DC power supply and the converter. The first element to the third element are respectively arranged relative to the first busbar to the third busbar, and detect the magnetic flux generated by the current flowing through each busbar in a coreless manner. The maximum current flowing through the second busbar is smaller than the maximum current of the first busbar and the maximum current of the third busbar. The second busbar is arranged between the first busbar and the third busbar.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese Patent Application No. 2020-062632 filed on Mar. 31, 2020, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The disclosure in this specification relates to a current detection device. BACKGROUND ART

[0004] Patent Document 1 discloses a power conversion device including a voltage converter, a first inverter, and a second inverter. The voltage converter boosts the voltage of the DC power output from the battery and supplies it to each inverter. The first inverter converts the supplied DC into AC and outputs it to a first motor. The second inverter converts the supplied DC into AC and outputs it to a second motor.

[0005] In addition, Patent Document 1 discloses a current detection device used in the above power conversion device. The current detection device includes a terminal unit in which first to third current sensors are built in. The first current sensor measures the output current of the first inverter, the second current sensor measures the output current of the second inverter, and the third current sensor measures the current flowing through the reactor of the voltage converter.

[0006] PRIOR ART DOCUMENTS

[0007] Patent Documents

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-39734 SUMMARY OF THE INVENTION

[0009] In addition, a general current sensor has a magnetic core part (Japanese: 集磁コア) and a magnetic detection element. The magnetic core part is shaped to surround a bus bar through which a current to be measured flows, and forms a path for magnetic flux generated by the current flowing through the bus bar. The magnetic detection element is disposed in a gap formed in the magnetic core part, and detects the magnitude of the current flowing through the bus bar by detecting the magnitude of the magnetic flux passing through the gap.

[0010] On the other hand, in recent years, the development of a coreless current sensor that removes such a magnetic core part has been continuously progressing. If a coreless structure can be achieved, significant miniaturization of a current detection device including a plurality of current sensors can be realized. However, with the development of such miniaturization achieved by the coreless structure, the interval between a plurality of bus bars becomes smaller. As a result, technical problems such as increased thermal interference and magnetic interference between adjacent bus bars newly occur.

[0011] An object disclosed is to provide a current detection device which can suppress the increase of thermal interference and magnetic interference and can be miniaturized by adopting a coreless current sensor.

[0012] The current detection device disclosed herein is used for a power conversion device, and the power conversion device comprises:

[0013] a converter that boosts the voltage of electric power supplied from a DC power source;

[0014] a first inverter that converts the DC voltage boosted by the converter into AC voltage and outputs the AC voltage to the first rotating electric machine; and

[0015] The second inverter converts the DC boosted by the converter into AC and outputs it to the second rotating electrical machine, wherein the current detection device comprises:

[0016] a first conductor that forms a portion of a current path between the first inverter and the first rotating electric machine;

[0017] a second conductor that forms a portion of a current path between the second inverter and the second rotating electric machine;

[0018] a third conductor, the third conductor forming a part of a current path between the DC power source and the converter;

[0019] a first element disposed opposite to the first conductor and detecting a magnetic flux generated by a current flowing through the first conductor in a coreless manner;

[0020] a second element disposed opposite to the second conductor and detecting a magnetic flux generated by a current flowing through the second conductor in a coreless manner; and

[0021] a third element, the third element being arranged opposite to the third conductor and detecting the magnetic flux generated by the current flowing in the third conductor in a coreless manner,

[0022] The maximum current flowing through the second conductor is smaller than the maximum current flowing through the first conductor, and smaller than the maximum current flowing through the third conductor,

[0023] The second conductor is arranged along a predetermined direction along with the first conductor and the third conductor, and is arranged between the first conductor and the third conductor.

[0024] Here, there is a difference in the maximum current flowing through each of the first busbar to the third busbar. In addition, when the first busbar to the third busbar are arranged in a specified direction, if the busbars with larger maximum currents are arranged adjacent to each other, the thermal interference and magnetic interference between them will become larger. In view of this, in the above-mentioned current detection device, the busbar (second busbar) with the smallest maximum current among the first busbar to the third busbar is arranged between the other busbars (first busbar, third busbar). Therefore, the interval between the first busbar and the third busbar can be increased, and the thermal interference and magnetic interference between the busbars with larger maximum currents can be suppressed.

[0025] As described above, by adopting a coreless current sensor, it is possible to achieve miniaturization of the current detection device, and it is also possible to suppress increases in thermal interference and magnetic interference caused by miniaturization.

[0026] The multiple methods disclosed in this specification use different technical means to achieve various purposes. The claims and the symbols in brackets recorded in the claims exemplarily represent the correspondence between the parts of the embodiments described later and are not intended to limit the technical scope. The purpose, features and effects disclosed in this specification can be more clearly understood by referring to the subsequent detailed description and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a circuit diagram of a power conversion device to which the current detection device of the first embodiment is applied.

[0028] Figure 2 It is a side view showing the power conversion device.

[0029] Figure 3 It is a top view showing the power conversion device.

[0030] Figure 4 It is a cross-sectional view showing the interference of multiple components.

[0031] Figure 5 It is a top view of the current detection device according to the second embodiment. DETAILED DESCRIPTION

[0032] A plurality of embodiments are described with reference to the accompanying drawings. In a plurality of embodiments, sometimes the same reference symbols are used for functionally and / or structurally corresponding parts and / or associated parts, or different reference symbols are used for the parts with more than one hundred digits. For the corresponding parts and / or associated parts, reference can be made to the description of other embodiments.

[0033] (First Embodiment)

[0034] exist Figure 1In the embodiment, the power conversion device 100 is installed in an electric vehicle. The power conversion device 100 controls the power supplied to the rotating motor in the electric vehicle and the power regenerated from the rotating motor. In addition, the electric vehicle includes a hybrid vehicle using an internal combustion engine and a rotating motor as a power source and an electric vehicle using only a rotating motor as a power source. The power conversion device 100 provides power conversion between a plurality of devices including a first rotating motor 1, a second rotating motor 2 and a DC power supply 3. The power conversion device 100 includes a current detection device.

[0035] The first rotating electric machine 1 and the second rotating electric machine 2 are three-phase AC rotating electric machines. The first rotating electric machine 1 is mainly used as a driving source for the vehicle. The second rotating electric machine 2 is mainly used as a generator for generating electricity using the rotating driving force output from the internal combustion engine of the vehicle. The DC power supply 3 is a power supply unit that outputs a DC voltage including a rechargeable secondary battery such as a lithium-ion battery. The DC power supply 3 may also be a fuel cell, for example.

[0036] The power conversion device 100 includes a capacitor 110 as a filter, a converter 120, a smoothing capacitor 130, a first inverter 140a, a second inverter 140b, a sensor unit 160, and a control circuit 170 (CNTR).

[0037] The capacitor 110 is provided between the positive line 10P and the negative line 10N. The positive line 10P is a power line connected to the positive electrode of the DC power source 3 and is provided by an electric wire and / or a bus bar. The negative line 10N is a power line connected to the negative electrode of the DC power source 3 and is provided by an electric wire and / or a bus bar. The capacitor 110 functions as a filter for removing noise of the DC voltage supplied from the DC power source 3 to the converter 120.

[0038] The converter 120 is a voltage conversion circuit. The converter 120 is a circuit that converts the ratio of the potential difference between the positive line 10P and the negative line 10N and the potential difference between the high potential line 20H and the low potential line 20L. The high potential line 20H and the low potential line 20L are lines for large electric power flowing through the first rotating electrical machine 1 and the second rotating electrical machine 2. The converter 120 is a conversion circuit that converts a DC voltage into a DC voltage of a different voltage. The converter 120 is used for conversion of the DC voltage between the DC power supply 3 and the first inverter 140a and between the DC power supply 3 and the second inverter 140b. The converter 120 functions as a boost circuit that boosts the DC voltage supplied from the DC power supply 3. The converter 120 can also function as a buck circuit that bucks the voltage between the high potential line 20H and the low potential line 20L.

[0039] Converter 120 includes a semiconductor switching element and a reactor 60. The semiconductor switching element is provided by a reverse-conducting insulated gate bipolar transistor shown in the figure. The semiconductor switching element can be provided by various elements such as a power MOSFET and a SiC transistor.

[0040] The converter 120 includes two semiconductor switch elements connected in series between the high potential line 20H and the low potential line 20L. The plurality of semiconductor switch elements are provided by a module 40 in which the plurality of semiconductor switch elements are housed in one package.

[0041] The converter 120 has one module 40 and one reactor 60. However, if it is desired to improve the voltage boosting capability of the converter 120, the converter 120 may have a plurality of modules 40 and a plurality of reactors 60. The reactor 60 is arranged in series between the connection point of the high-side semiconductor switching element and the low-side semiconductor switching element and the positive line 10P.

[0042] The smoothing capacitor 130 is provided between the high potential line 20H and the low potential line 20L. The smoothing capacitor 130 has a function of smoothing the voltage between the high potential line 20H and the low potential line 20L.

[0043] The first inverter 140a is disposed between the high potential line 20H and the low potential line 20L and the first rotating electrical machine 1. The first inverter 140a performs DC-AC conversion between DC power and three-phase AC power. The first inverter 140a converts power flowing through the first rotating electrical machine 1.

[0044] The second inverter 140b is disposed between the high potential line 20H and the low potential line 20L and between the second rotating electrical machine 2. The second inverter 140b performs DC to AC conversion between DC power and three-phase AC power. The second inverter 140b converts power flowing through the second rotating electrical machine 2.

[0045] The first inverter 140a and the second inverter 140b include a plurality of semiconductor switching elements. The plurality of semiconductor switching elements provide two sets of three-phase bridge circuits. The high-side semiconductor switching elements and the low-side semiconductor switching elements in the first inverter 140a and the second inverter 140b are provided by the module 40. The first inverter 140a and the second inverter 140b include a plurality of modules 40. Among the plurality of modules 40, the module included in the first inverter 140a is equivalent to the first module 41, and the module included in the second inverter 140b is equivalent to the second module 42. In addition, among the plurality of modules 40, the module included in the converter 120 is equivalent to the third module 43.

[0046] The first inverter 140a has three first modules 41. The second inverter 140b has three second modules 42. In the illustrated example, the power conversion device 100 has seven modules 40.

[0047] In the illustrated example, one module 40 has two semiconductor switch elements. Alternatively, one module 40 can include a plurality of semiconductor switch elements. One module 40 can also accommodate, for example, a set of three-phase bridge circuits. In addition, one module 40 can also accommodate a plurality of semiconductor switch elements on the high side or the low side. The number and circuit structure of the semiconductor switch elements accommodated in one module 40 can be varied in various ways.

[0048] The sensor unit 160 provides a “current detection device” that detects a current flowing through each portion of the power conversion device 100 . The sensor unit 160 includes a plurality of detection units 161 , 162 , and 163 .

[0049] The first detection unit 161 of the plurality of detection units detects the first current I1 between the first inverter 140a and the first rotating motor 1. The second detection unit 162 detects the second current I2 between the second inverter 140b and the second rotating motor 2. The third detection unit 163 detects the third current I3 flowing through the converter 120. The sensor unit 160 includes a coreless current sensor arranged close to a conductor as a detection object. The sensor unit 160 includes a plurality of busbars 61b, 62b, and 63b as a plurality of conductors. The sensor unit 160 includes a plurality of coreless current sensors. The coreless current sensor does not include a larger magnetic core for gathering the magnetic flux generated by the current as the detection object, but detects the magnetic flux generated by the current as the detection object.

[0050] The control circuit 170 has a function of controlling the operation of a plurality of semiconductor switching elements in the converter 120, the first inverter 140a, and the second inverter 140b. The control circuit 170 includes, for example, a microcomputer having a memory for recording control software and a processor for executing the software.

[0051] The control circuit 170 controls the operation of the plurality of semiconductor switching elements based on the current detected by the sensor unit 160, etc., thereby controlling the power conversion. The control circuit 170 is configured to respond to instructions from a higher-level control device provided inside or outside the vehicle, for example. The control circuit 170 sets a target variation pattern of the current flowing through each phase of the first rotating electrical machine 1 and / or the second rotating electrical machine 2, for example, based on an output torque requirement signal from the higher-level control device. The control circuit 170 monitors the current flowing through the first rotating electrical machine 1, the second rotating electrical machine 2, and the converter 120 through the sensor unit 160. The control circuit 170 performs feedback control on the first inverter 140a and / or the second inverter 140b to achieve the target variation pattern.

[0052] The power conversion device 100, for example, converts the DC voltage supplied from the DC power supply 3 into a three-phase AC and supplies it to the first rotating motor 1. The power conversion device 100 uses the power charged to the DC power supply 3 and drives the vehicle through the first rotating motor 1. This operation mode is called the EV drive mode. The power conversion device 100, for example, converts the three-phase AC supplied from the second rotating motor 2 that generates electricity using the rotational driving force of the internal combustion engine into a three-phase AC with different frequencies, etc., and supplies it to the first rotating motor 1. The power conversion device 100 uses the power generated using the rotational driving force of the internal combustion engine and drives the vehicle through the first rotating motor 1. This operation mode is called the in-line HV drive mode. In addition, the power conversion device 100 sometimes provides, for example, a regenerative drive mode in which the first rotating motor 1 and / or the second rotating motor 2 acts as a generator and charges the DC power supply 3.

[0053] The circuit including the first rotating motor 1 and the first inverter 140a provides a first switching circuit LD1 through which a controllable first current I1 flows. The first switching circuit LD1 includes an electric wire and / or a busbar that provides an energization path. In other words, the first switching circuit LD1 controls the first current I1. The circuit including the second rotating motor 2 and the second inverter 140b provides a second switching circuit LD2 through which a controllable second current I2 flows. The second switching circuit LD2 includes an electric wire and / or a busbar that provides an energization path. In other words, the second switching circuit LD2 controls the second current I2. The converter 120 provides a third switching circuit LD3 through which a controllable third current I3 flows. The third switching circuit LD3 includes an electric wire and / or a busbar that provides an energization path. In other words, the third switching circuit LD3 controls the third current I3. The plurality of switching circuits LD1, LD2, and LD3 are also referred to as load circuits.

[0054] The current relationship of the currents flowing through the plurality of switch circuits LD1 , LD2 , and LD3 satisfies at least the third and fourth conditions described below. It is desirable that all of the first to fourth conditions are satisfied.

[0055] First condition: I1>I2…Formula (1)

[0056] Second condition: I1>I3…Formula (2)

[0057] The third condition: I2max<I1max…Formula (3)

[0058] Fourth condition: I2max<I3max…Formula (4)

[0059] The assumed maximum value of the first current I1 is set as the first maximum current I1max. The assumed maximum value of the second current I2 is set as the second maximum current I2max. The assumed maximum value of the third current I3 is set as the third maximum current I3max.

[0060] The current relationship shown in the above equations (1) to (4) can be achieved by setting the action of the first rotating motor 1, the second rotating motor 2 and the converter 120. For example, the above current relationship can be achieved by using the first rotating motor 1 as the main power source for driving. In addition, the above current relationship can also be achieved by configuring the structure of the power transmission system between the first rotating motor 1 and the second rotating motor 2 and the drive wheels of the vehicle. The structure of the power transmission system can utilize a variety of structures such as planetary gears. The current relationship shown in the above equations (1) to (4) is sometimes achieved by controlling the control circuit 170. The power conversion device 100 provides multiple different operating modes, for example, by controlling the converter 120, the first inverter 140a and the second inverter 140b.

[0061] The above current relationship can be provided in the above EV drive mode. For example, in equations (3) and (4), there is also a relationship between the maximum value of the second current I2 in the EV drive mode, the maximum value of the third current I3 in the EV drive mode, and the maximum value of the first current I1 in the EV drive mode.

[0062] The above current relationship can sometimes also be provided in the above inline HV driving mode. For example, in equations (3) and (4), there is also a relationship of the maximum value of the second current I2 in the inline HV driving mode, the maximum value of the third current I3 in the inline HV driving mode, and the maximum value of the first current I1 in the inline HV driving mode.

[0063] The above current relationship can sometimes be provided in both the EV drive mode and the inline HV drive mode. For example, in equations (3) and (4), there is also a relationship between the maximum value of the second current I2 in the two modes, the maximum value of the third current I3 in the two modes, and the maximum value of the first current I1 in the two modes.

[0064] In addition, the current relationship shown in the above equations (1) to (4) also appears in the current flowing between the plurality of switch circuits LD1, LD2, LD3 (the switch unit 140 described later) and the smoothing capacitor 130. The current flowing between the second switch circuit LD2 and the smoothing capacitor 130 is smaller than the current flowing between the first switch circuit LD1 and the smoothing capacitor 130. The current flowing between the second switch circuit LD2 and the smoothing capacitor 130 is smaller than the current flowing between the third switch circuit LD3 and the smoothing capacitor 130. According to the structure shown in the figure, the heat generated by Joule heat is the smallest in the second switch circuit LD2. In addition, due to the size of the second current I2, the surge voltage caused by the inductance component is the smallest in the second switch circuit LD2.

[0065] exist Figure 2 and Figure 3 , the configuration of multiple components in the power conversion device 100 is shown. Figure 2 yes Figure 3 Side view in the direction of arrow II. Figure 3 yes Figure 2 The top view of arrow III. Figure 2 and Figure 3 , for convenience, an orthogonal coordinate system including a height direction XD, a width direction YD, and a depth direction ZD is shown. The height, width, and depth are referred to for convenience and do not limit the installation posture of the power conversion device 100. The power conversion device 100 can take a variety of postures relative to the gravity direction. The power conversion device 100 has a housing 90. The housing 90 accommodates a plurality of components used for the power conversion device 100.

[0066] The power conversion device 100 includes a plurality of modules 40. Each module 40 is a flat semiconductor module. Each module 40 includes three power terminals 44 including a high potential terminal 44H, a low potential terminal 44L and a connection point terminal 44M. The high potential terminal 44H is connected to the high potential line 20H. The low potential terminal 44L is connected to the low potential line 20L. The connection point terminal 44M is a connection point between the semiconductor switch element on the high side and the semiconductor switch element on the low side. The connection point terminal 44M is connected to the first rotating motor 1, the second rotating motor 2 or the reactor 60. Each module 40 includes a plurality of control terminals 45 for control signals and monitoring signals. The plurality of control terminals 45 are connected to the control circuit 170. The plurality of power terminals 44 and the plurality of control terminals 45 extend from the edge of the module 40 in the height direction XD.

[0067] A plurality of modules 40 are arranged in a stacked manner along the depth direction ZD. A plurality of modules 40 are arranged in such a manner that their respective plate-shaped main planes are parallel and their respective plate-shaped main planes overlap. A plurality of modules 40 are arranged in such a manner that their respective edges are aligned along the depth direction ZD. A plurality of modules 40 provide a plurality of power terminals 44 including at least a high potential terminal 44H and a low potential terminal 44L. A plurality of power terminals 44 are arranged in such a manner as to form a plurality of columns. Three power terminals 44 protrude from the side of the module 40 facing the height direction XD along the height direction XD. Power terminals 44 of the same type protruding from different modules 40 are arranged in such a manner as to form a row along the depth direction ZD. In other words, a plurality of modules 40 are arranged in the depth direction ZD in such a manner that a plurality of power terminals 44 form a plurality of columns. In the following description, the depth direction ZD is also referred to as the arrangement direction. In addition, the range in which the plurality of power terminals 44 in the arrangement direction are located is also referred to as the arrangement range RG.

[0068] The power conversion device 100 includes a cooler 50 for cooling the plurality of modules 40. The cooler 50 has a flow path for circulating a cooling medium such as water. The plurality of modules 40 and the cooler 50 provide a liquid-cooled switch unit 140. Thus, the switch unit 140 includes a plurality of modules 40 that accommodate semiconductor switching elements and have power terminals 44. The switch unit 140 includes a cooler 50 for cooling the plurality of modules 40.

[0069] In the switch unit 140, the plurality of power terminals 44 are arranged in three rows along the arrangement direction. The plurality of power terminals 44 may also be arranged in multiple rows of various numbers such as one row, two rows, three rows, or four rows.

[0070] In other words, in the switch unit 140, the plurality of power terminals 44 of the first switch circuit LD1, the second switch circuit LD2, and the third switch circuit LD3 are arranged in a prescribed order within the arrangement range RG. The plurality of power terminals 44 are arranged in such a manner that the power terminal 44 of the first switch circuit LD1 and the power terminal 44 of the third switch circuit LD3 are located on both sides of the power terminal 44 of the second switch circuit LD2. In other words, the prescribed order is the order of the first switch circuit LD1, the second switch circuit LD2, and the third switch circuit LD3.

[0071] The second module 42 through which the second current I2 flows is located between the first module 41 through which the first current I1 greater than the second current I2 flows and the third module 43 through which the third current I3 greater than the second current I2 flows. The second module 42 is located in the middle area of ​​the switch unit 140, and the first module 41 and the third module 43 are located in the two end areas, respectively.

[0072] The reactor 60 is arranged beside the switch unit 140 in the depth direction ZD. The reactor 60 is arranged over the capacitor unit 30, the switch unit 140, and the sensor unit 160. The control circuit 170 is arranged above the switch unit 140 in the height direction XD. The circuit substrate in the control circuit 170 is connected to the plurality of control terminals 45 above the switch unit 140. In addition, the arrangement of the capacitor unit 30, the reactor 60, the sensor unit 160, and the control circuit 170 relative to the switch unit 140 is not limited to the arrangement shown in the figure.

[0073] The high potential line 20H is provided by a bus bar 131. The bus bar 131 is electrically connected to a plurality of high potential terminals 44H. The low potential line 20L is provided by a bus bar 133. The bus bar 133 is electrically connected to a plurality of low potential terminals 44L.

[0074] The bus bars 131 and 133 are also bus bars for connecting the capacitor elements 30a housed in the capacitor unit 30. The bus bars 131 and 133 are also called capacitor bus bars.

[0075] The capacitor unit 30 includes a plurality of capacitor elements 30 a connected in parallel. In the figure, three capacitor elements 30 a are illustrated. The capacitor unit 30 may include one, two, or four or more capacitor elements 30 a. In addition to the smoothing capacitor 130 , the capacitor unit 30 may also accommodate the capacitor 110 .

[0076] The bus bar 131 is electrically connected to the plurality of power terminals 44. The bus bar 133 is electrically connected to the plurality of power terminals 44. The bus bars 131 and 133 each have a wide width in the depth direction ZD within the arrangement range RG, and electrically connect the plurality of power terminals 44 and the capacitor element 30a within the width.

[0077] The sensor unit 160 includes a plurality of detection units 161, 162, and 163. The detection units 161, 162, and 163 detect the current flowing through the connection point terminal 44M and output the detection signal to the control circuit 170. The sensor unit 160 is connected to the control circuit 170. In the sensor unit 160, each of the detection units 161, 162, and 163 includes Figure 3 The sensor unit 160 is a partially broken diagram of the element. The sensor unit 160 houses a plurality of detection units 161, 162, and 163 in a main body 164 made of insulating resin. The sensor unit 160 also serves as a terminal block.

[0078] The sensor unit 160 has a pair of magnetic shielding plates 60d and 60e extending over the range of the plurality of detection parts 161, 162, and 163. The shielding plates 60d and 60e provide shielding against external magnetic flux coming from the outside of the sensor unit 160. The sensor unit 160 has a circuit board 60c as a supporting member extending over the range of the plurality of detection parts 161, 162, and 163.

[0079] The plurality of detection units 161, 162, 163 have bus bars 61b, 62b, 63b, respectively. The bus bars 61b, 62b, 63b have terminals 61p for external connection and terminals 61q for connection to the connection point terminal 44M. The bus bars 61b, 62b, 63b are crank-shaped with at least one bend.

[0080] The plurality of busbars 61b, 62b, and 63b are arranged at the same position in the height direction XD and arranged in a row in the depth direction ZD (prescribed direction). The same is true for the plurality of terminals 61p and 61q, which are arranged at the same position in the height direction XD and arranged in a row in the depth direction ZD. In addition, as the connection point terminals 44M are arranged at equal intervals in the depth direction ZD, the plurality of terminals 61q, 62q, and 63q are also arranged at equal intervals in the depth direction ZD.

[0081] The plurality of detection units 161, 162, 163 respectively have coreless current sensors, namely, elements 61a, 62a, 63a, mounted on the circuit board 60c. The first element 61a of the plurality of elements detects the first current I1, the second element 62a detects the second current I2, and the third element 63a detects the third current I3. The elements 61a, 62a, 63a are arranged close to and opposite to the busbars 61b, 62b, 63b. The elements 61a, 62a, 63a output a signal representing the current by detecting the magnetic flux caused by the current flowing through the busbars 61b, 62b, 63b.

[0082] To explain in more detail, each of the plurality of busbars 61b, 62b, 63b generates a magnetic flux by the current flowing in the busbar. The current flowing in one of the plurality of busbars 61b, 62b, 63b generates a regular magnetic flux to be detected. The regular magnetic flux interlinks with the element 61a, 62a, 63a corresponding to the busbar 61b, 62b, 63b. The element 61a, 62a, 63a generates and outputs an electrical signal corresponding to the regular magnetic flux. The electrical signal is used as a signal representing the current flowing through the busbar 61b, 62b, 63b.

[0083] Figure 4 The case where the current to be detected flows through the second switch circuit LD2 is illustrated. Figure 4In the case of , each of the plurality of second bus bars 62b belonging to the plurality of second detection units 162 generates a normal magnetic flux M2. Each of the plurality of second elements 62a belonging to the plurality of first detection units 161 outputs an electrical signal caused by the magnetic flux M2.

[0084] The plurality of elements 61a, 62a, 63a are arranged at the same position in the height direction XD and arranged in the depth direction ZD. The direction in which the elements 61a, 62a, 63a are arranged (the depth direction ZD) is parallel to the direction in which the modules 41, 42, 43 are arranged. The plurality of elements 61a, 62a, 63a are arranged at the same position in the width direction YD. That is, Figure 3 As shown, the plurality of elements 61a, 62a, and 63a are arranged side by side on a straight line extending in the depth direction ZD.

[0085] The shape of the portion of the plurality of busbars 61b, 62b, 63b that faces the elements 61a, 62a, 63a, i.e., the shape of the cross section perpendicular to the width direction YD, is a rectangle. In other words, the shape of the cross section perpendicular to the direction in which the current flows in the busbars 61b, 62b, 63b is a rectangle. The plurality of busbars 61b, 62b, 63b are arranged in such a way that the long side of the rectangle is parallel to the predetermined direction (depth direction ZD) in which the busbars 61b, 62b, 63b are arranged (see Figure 4 ) In other words, the elements 61a, 62a, 63a are arranged to face the long sides Fa of the rectangles of the busbars 61b, 62b, 63b.

[0086] The first detection unit 161 among the plurality of detection units detects the first current I1 flowing through the first switch circuit LD1. The bus bar in the first detection unit 161, namely the first bus bar 61b, belongs to the first switch circuit LD1. The first bus bar 61b is equivalent to a first conductor that forms a part of the current path between the first inverter 140a and the first rotating electric machine 1. The sensor unit 160 includes three first detection units 161 to detect three-phase power. The three first detection units 161 are arranged adjacent to each other to form a group of detection units 161. A group of first detection units 161 is arranged next to a plurality of connection point terminals 44M belonging to the first switch circuit LD1.

[0087] The second detection unit 162 among the plurality of detection units detects the second current I2 flowing in the second switch circuit LD2. The bus bar in the second detection unit 162, namely the second bus bar 62b, belongs to the second switch circuit LD2. The second bus bar 62b is equivalent to a second conductor that forms a part of the current path between the second inverter 140b and the second rotating motor 2. The sensor unit 160 includes three second detection units 162 to detect three-phase power. The three second detection units 162 are arranged adjacent to each other to form a group of detection units 162. A group of second detection units 162 is arranged next to a plurality of connection point terminals 44M belonging to the second switch circuit LD2.

[0088] The third detection unit 163 among the plurality of detection units detects the third current I3 flowing through the third switch circuit LD3. The bus bar in the third detection unit 163, namely the third bus bar 63b, belongs to the third switch circuit LD3. The third bus bar 63b is equivalent to a third conductor that forms a part of the current path between the DC power supply 3 and the converter 120. The sensor unit 160 includes a third detection unit 163 to detect the single-phase power in the converter 120. The third detection unit 163 is arranged next to the connection point terminal 44M belonging to the third switch circuit LD3. In the case where the converter 120 has a plurality of detection objects, the sensor unit 160 may also include a plurality of third detection units 163. In this case, the plurality of third detection units 163 are arranged adjacent to each other in such a manner as to form a group of detection units 163.

[0089] The set of second detection parts 162 is arranged between the set of first detection parts 161 and the set of third detection parts 163 in the arrangement direction. The sensor unit 160 extends in the arrangement range RG of the plurality of power terminals 44 along the arrangement direction of the plurality of power terminals 44. In the illustrated example, the sensor unit 160 extends in the depth direction ZD in the range covering all the connection point terminals 44M.

[0090] exist Figure 4 , for ease of understanding, the outer shape of a single sensor unit 160 including a plurality of detection portions is shown. Hatching representing the resin material (ie, the body 164) forming the sensor unit 160 is not shown.

[0091] In the sensor unit 160, a pair of shield plates 60d and 60e are disposed opposite to each other so as to sandwich the elements 61a, 62a, and 63a and the bus bars 61b, 62b, and 63b. Figure 3 and Figure 4 In the example of FIG. 5 , a pair of shielding plates 60d and 60e are arranged side by side in the width direction YD.

[0092] The portion of the pair of shielding plates 60d and 60e sandwiching the first element 61a and the first bus bar 61b corresponds to the first magnetic shield. The portion sandwiching the second element 62a and the second bus bar 62b corresponds to the second magnetic shield. The portion sandwiching the third element 63a and the third bus bar 63b corresponds to the third magnetic shield. Figure 4 In the example of FIG. 1 , the first magnetic shield, the second magnetic shield, and the third magnetic shield are integrally formed and connected. However, these magnetic shields may be separately formed and separated.

[0093] Hereinafter, the effects of the sensor unit 160 as the current detection device achieved by including the above-mentioned structure will be described.

[0094] In this embodiment, since a coreless current sensor without a magnetic core is used, the sensor unit 160 can be significantly miniaturized compared to a current sensor using a magnetic core. In addition, the increase in thermal interference and magnetic interference caused by miniaturization described below can be suppressed.

[0095] There is a difference in the maximum current flowing through each of the first busbar 61b, the second busbar 62b, and the third busbar 63b. That is, the first maximum current I1max, the second maximum current I2max, and the third maximum current I3max are different. In addition, when these busbars 61b, 62b, and 63b are arranged in a predetermined direction (depth direction ZD), if the busbars with larger maximum currents are arranged adjacent to each other, the thermal interference and magnetic interference between them will become larger.

[0096] For example, in contrast to the present embodiment, when the first busbar 61b and the third busbar 63b are arranged adjacent to each other, thermal interference is large, such that the temperature of the third busbar 63b rises due to the heat generated in the first busbar 61b, or the temperature of the first busbar 61b rises due to the heat generated in the third busbar 63b. In addition, magnetic interference is large, such that the magnetism generated by the current flowing through the first busbar 61b becomes an obstacle to the current flowing through the third busbar 63b, or the magnetism generated by the current flowing through the third busbar 63b becomes an obstacle to the current flowing through the first busbar 61b.

[0097] In view of these points, in the present embodiment, the busbar with the smallest maximum current among the busbars 61b, 62b, and 63b is arranged between the other busbars. That is, in the present embodiment, since the second maximum current I2max is smaller than the first maximum current I1max and the third maximum current I3max, the second busbar 62b is arranged between the first busbar 61b and the third busbar 63b. Therefore, the interval between the first busbar 61b and the third busbar 63b can be increased, and the thermal interference and magnetic interference between the busbars with larger maximum currents can be suppressed.

[0098] As described above, according to the present embodiment, by adopting the coreless current sensor, the sensor unit 160 can be significantly miniaturized, and the increase in thermal interference and magnetic interference caused by miniaturization can be suppressed.

[0099] Here, the first magnetic shield, the second magnetic shield, and the third magnetic shield receive radiation heat from the busbars 61b, 62b, and 63b, respectively, and dissipate the heat to the outside air. Therefore, the larger the area of ​​the shield, the lower the ambient temperature of the busbars 61b, 62b, and 63b, thereby contributing to lowering the temperature of the busbars 61b, 62b, and 63b.

[0100] In view of this, in the present embodiment, the first magnetic shield, the second magnetic shield, and the third magnetic shield are integrally formed and connected as shielding plates 60d and 60e. Therefore, the area of ​​the shield can be increased, and it can contribute to the temperature reduction of the busbars 61b, 62b, and 63b. In particular, it is assumed that the heat generated by the first busbar 61b is greater than that of the other busbars. In addition, as described above, by forming the shield integrally, the heat generated in the first busbar 61b is conducted from the first magnetic shield to the second magnetic shield and the third magnetic shield. Therefore, it is possible to promote the reduction of the ambient temperature of the first busbar 61b.

[0101] In addition, in this embodiment, the first element 61a, the second element 62a, and the third element 63a are arranged in a straight line. Therefore, compared with the case where the elements 61a, 62a, and 63a are arranged alternately in the width direction YD, the size of the sensor unit 160 in the width direction YD can be reduced. Specifically, the shielding plates 60d and 60e can be reduced in size in the width direction YD, and the main body 164 can be reduced in size in the width direction YD.

[0102] In addition, in the present embodiment, the cross-section of the busbars 61b, 62b, 63b arranged in the prescribed direction (depth direction ZD) perpendicular to the direction in which the current flows is in the shape of a rectangle. In addition, the busbars 61b, 62b, 63b are arranged in a direction in which the long side direction of the rectangle is parallel to the prescribed direction. On this basis, the plurality of elements 61a, 62a, 63a are arranged relative to the long side surface Fa of the above-mentioned rectangle of the busbars 61b, 62b, 63b.

[0103] Thus, the detection accuracy of the current value can be improved compared to the case where the elements 61a, 62a, 63a are arranged opposite to the short sides of the busbars 61b, 62b, 63b. In addition, since the layout is such that no elements are arranged between the adjacent busbars 61b, 62b, 63b, the sensor unit 160 can be miniaturized in the depth direction ZD. In short, the miniaturization in the depth direction ZD can be achieved while improving the detection accuracy.

[0104] (Second Embodiment)

[0105] In the first embodiment, the plurality of elements 61a, 62a, 63a are arranged at equal intervals in the depth direction ZD. Figure 5 As shown, the plurality of elements 61a, 62a, 63a are arranged at unequal intervals.

[0106] In the first embodiment, one first module 41 is provided for each phase of the first rotating electrical machine 1. In contrast, in the present embodiment, two first modules 41 are provided for each phase of the first rotating electrical machine 1. Accordingly, two terminals 61q of the present embodiment are provided for each of the first elements 61a. That is, two terminals 61q are formed by branching from one first bus bar 61b.

[0107] Similarly, the third busbar 63b is also branched to form two terminals 61q. In addition, the third module 43 and the reactor 60, which are one in the first embodiment, are included in three in this embodiment. Accordingly, the third element 63a in this embodiment is included in three. The plurality of terminals 61q, 62q, and 63q are arranged at equal intervals in the depth direction ZD (see Figure 5 This spacing is consistent with the spacing of the connection point terminals 44M.

[0108] As described above, the pitch of the plurality of elements 61a, 62a, 63a in the depth direction ZD is inconsistent with the pitch of the connection point terminal 44M in the depth direction ZD. In addition, the shape of the busbars 61b, 62b, 63b is set so that the pitch of the plurality of terminals 61q, 62q, 63q is consistent with the pitch of the connection point terminal 44M.

[0109] (Other embodiments)

[0110] The disclosure in this specification and the drawings, etc. is not limited to the illustrated embodiments. The present disclosure includes the illustrated embodiments and the variations made by those skilled in the art based thereon. For example, the present disclosure is not limited to the combination of components and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The present disclosure may have additional parts that can be added to the embodiments. The present disclosure includes embodiments in which components and / or elements of the embodiments are omitted. The present disclosure includes the replacement or combination of components and / or elements between one embodiment and other embodiments. The disclosed technical scope is not limited to the description of the embodiments. The disclosed several technical scopes should be understood to be represented by the description of the claims, and also include all variations within the meaning and scope equivalent to the description of the claims.

[0111] The disclosure in the specification and drawings is not limited by the claims. The disclosure in the specification and drawings includes the technical ideas described in the claims and involves more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, it is possible to extract a variety of technical ideas from the disclosure in the specification and drawings without being restricted by the claims.

[0112] In the first embodiment, the rigid busbars 61b, 62b, 63b are used as the conductors for the elements 61a, 62a, 63a to be arranged opposite to each other. However, the busbars 61b, 62b, 63b may be flexible electric wires.

[0113] In the first embodiment, the shielding plates 60d and 60e are arranged opposite to each other so as to sandwich the elements 61a, 62a, 63a and the busbars 61b, 62b, 63b. In contrast, the other of the pair of shielding plates 60d and 60e may be removed. In addition, the pair of shielding plates 60d and 60e may be connected to each other and formed by one shielding plate.

[0114] In the first embodiment, the layout is such that the elements 61a, 62a, 63a are not arranged between the adjacent busbars 61b, 62b, 63b. In contrast, the layout may be such that the elements 61a, 62a, 63a are arranged between the adjacent busbars 61b, 62b, 63b. In this case, it is desirable to Figure 4 The directions of the busbars 61b, 62b, and 63b shown in the figure are rotated by 90 degrees to form a layout in which the long side faces Fa are opposed to the elements 61a, 62a, and 63a.

Claims

1. A current detection device, the current detection device is used in a power conversion device, the power conversion device include: a converter that boosts the voltage of electric power supplied from a DC power source; a first inverter that converts the DC voltage boosted by the converter into AC voltage and outputs the AC voltage to a first rotating electrical machine; as well as The second inverter converts the DC boosted by the converter into AC and outputs it to the second rotating electrical machine, wherein the current detection device comprises: a first electrical conductor forming a portion of a current path between the first inverter and the first rotating electric machine; a second electrical conductor forming a portion of a current path between the second inverter and the second rotating electric machine; a third electrical conductor, the third electrical conductor forming a part of a current path between the DC power source and the converter; a first element disposed opposite to the first conductor and detecting a magnetic flux generated by a current flowing through the first conductor in a coreless manner; a second element disposed opposite to the second conductor and detecting a magnetic flux generated by a current flowing through the second conductor in a coreless manner; and a third element disposed opposite to the third conductor and detecting a magnetic flux generated by a current flowing through the third conductor in a coreless manner, The maximum current flowing through the second conductor is smaller than the maximum current flowing through the first conductor, and smaller than the maximum current flowing through the third conductor. The second conductor is arranged along a predetermined direction along with the first conductor and the third conductor, and is arranged between the first conductor and the third conductor.

2. The current detection device according to claim 1, It is characterized in that include: a pair of first magnetic shields, the pair of first magnetic shields being arranged opposite to each other so as to sandwich the first element and the first conductor; a pair of second magnetic shields, the pair of second magnetic shields being arranged opposite to each other so as to sandwich the second element and the second conductor; as well as a pair of third magnetic shields, the pair of third magnetic shields being arranged opposite to each other so as to sandwich the third element and the third conductor, The first magnetic shield, the second magnetic shield, and the third magnetic shield are integrally formed and connected.

3. The current detection device according to claim 1, It is characterized in that The first element, the second element and the third element are arranged in a straight line.

4. The current detection device according to any one of claims 1 to 3, It is characterized in that The first conductor, the second conductor, and the third conductor have a rectangular cross-section perpendicular to the direction in which the current flows, and are arranged in a direction in which the long sides of the rectangles are parallel to the predetermined direction. The first element, the second element, and the third element are arranged to face the long sides of the rectangle.

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