Motor drive device having DC link connection

Abstract

This motor drive device comprises: a housing that houses a power conversion device including at least one among a converter that converts AC power supplied from an AC power supply into DC power and an inverter that converts DC power supplied from the converter via a DC link into AC power for driving a motor; a busbar that is for electrically connecting the power conversion device to the DC link; and a connector that is for electrically connecting the busbar with the power conversion device when the busbar is inserted in said connector. The connector is mounted to the housing such that the insertion / removal direction of the busbar with respect to the connector is substantially perpendicular to the mounting surface of the connector onto the housing.

Description

Motor drive with DC link connection

[0001] The present disclosure relates to a motor drive having a DC link connection.

[0002] A motor drive device that drives an AC motor includes a converter and an inverter as power conversion devices. The converter and inverter are connected via a DC link. The converter converts AC power supplied from an AC power source into DC power and outputs it. The inverter converts DC power into AC power for driving the motor and outputs it.

[0003] Since a relatively large current flows in the DC link between the converter and the inverter, bus bars made of metal, for example copper, brass or aluminum, are often used for the DC link connections.

[0004] JP 2014-207803 A JP 2002-237341 A

[0005] When assembling a motor drive device, the DC output terminal of the converter and the DC input terminal of the inverter are electrically connected using a bus bar. There is a need for a motor drive device with a DC link connection that is easy to assemble.

[0006] According to one aspect of the present disclosure, a motor drive device includes a housing that houses a power conversion device which is either a converter that converts AC power supplied from an AC power supply into DC power or an inverter that converts DC power supplied from the converter via a DC link into AC power for driving the motor, a bus bar for electrically connecting the power conversion device to the DC link, and a connector for electrically connecting the bus bar to the power conversion device when the bus bar is inserted, and the connector is mounted on the housing so that the insertion and removal direction of the bus bar with respect to the connector is approximately perpendicular to the mounting surface of the connector on the housing.

[0007] FIG. 4 is a front view of a motor drive device according to an embodiment of the present disclosure. FIG. 5 is a circuit diagram of the motor drive device shown in FIG. 1. FIG. 6 is a side view of the motor drive device according to an embodiment of the present disclosure. FIG. 7 is a front view illustrating a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 8 is an enlarged view of the connector shown in FIG. 4. FIG. 9 is a perspective view (part 1) of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 10 is a front view of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 11 is a perspective view (part 2) of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 12 is a perspective view (part 3) of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 13 is a perspective view (part 4) of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 14 is a side view of a connector provided in a housing of the motor drive device according to an embodiment of the present disclosure. FIG. 15 is a perspective view (part 1) of a bus bar used for a DC link connection of the motor drive device according to an embodiment of the present disclosure and a support base. FIG. 16 is a perspective view of a support base supporting a bus bar used for a DC link connection of the motor drive device according to an embodiment of the present disclosure. FIG. 2 is a perspective view (part 2) of a bus bar and a support base used for DC link connection of the motor drive device according to an embodiment of the present disclosure; FIG. 3 is a front view of a connector into which a bus bar is inserted in the motor drive device according to an embodiment of the present disclosure; FIG. 4 is a side view of a connector into which a bus bar is inserted in the motor drive device according to an embodiment of the present disclosure; FIG. 5 is a perspective view of a connector into which a bus bar is inserted in the motor drive device according to an embodiment of the present disclosure; FIG. 6 is a front view showing a state in which a bus bar with a support base attached is inserted into a connector in the motor drive device according to an embodiment of the present disclosure; and FIG. 7 is a front view showing the size relationship between a housing and a bus bar in the motor drive device according to an embodiment of the present disclosure.

[0008] A motor drive device having a DC link connection according to an embodiment will be described below with reference to the drawings. In the following description, components having the same or similar functions are designated by the same reference numerals. Duplicate descriptions of those components may be omitted. The scale of the drawings has been appropriately changed to facilitate understanding.

[0009] In the following description, a converter that converts AC power supplied from an AC power source into DC power and outputs it is also referred to as a “rectifier device,” “rectifier circuit,” “rectifier,” or “forward converter.” An inverter that converts DC power into AC power and outputs it is also referred to as an “inverter.” Because converters and inverters are both devices that perform power conversion operations, they are collectively referred to as a “power conversion device.” That is, a power conversion device refers to any of a converter alone, an inverter alone, and a converter and inverter integrated together. A “DC link” refers to a circuit portion that electrically connects the DC output terminal of a converter and the DC input terminal of an inverter, and is also referred to as a “DC link unit,” “DC link,” “DC link unit,” “DC bus,” or “DC intermediate circuit.” A “DC link connection” refers to the formation of a DC link between the DC output terminal of a converter and the DC input terminal of an inverter. A “DC output terminal” includes a “positive DC output terminal” and a “negative DC output terminal.” "DC input terminal" includes "positive DC input terminal" and "negative DC input terminal". Bus bar is also called "bus bar" or "short bar". "Sheet metal" refers to a thin, flat metal. "Electrically connected" means "connected so that electricity can flow". "Parallel installation" means to align and arrange adjacently in a line. "Parallel installation direction" refers to the direction in which the housings are lined up when multiple housings are arranged in a line.

[0010] <Overall configuration of a motor drive device according to an embodiment of the present disclosure> Fig. 1 is a front view showing a motor drive device according to an embodiment of the present disclosure. Fig. 3 is a side view showing a motor drive device according to an embodiment of the present disclosure. Fig. 4 is a front view illustrating a connector provided in a housing of a motor drive device according to an embodiment of the present disclosure. Fig. 5 is an enlarged view of the connector shown in Fig. 4.

[0011] A motor drive device 1 according to an embodiment of the present disclosure includes a housing 11, a bus bar 12, and a connector 13. The motor drive device 1 also includes a converter, an inverter, a control board, sensors, communication equipment, a backup power supply, and other circuits. The motor drive device 1 may also include a display device and / or an input device.

[0012] In this disclosure, for the sake of simplicity, of the six faces of the housing 11, the face of the housing 11 on which the bus bar 12 is attached is referred to as the "front face" of the motor drive device 1. In the examples shown in Figures 1 and 3 to 20, for example, the face viewed from the negative Y-axis side to the positive Y-axis side on the XYZ coordinate axes is referred to as the "front face." For example, the front face of the motor drive device 1 is preferably the face that allows workers performing maintenance work and various operations to most easily and efficiently access the motor drive device 1.

[0013] The housing 11 houses a power conversion device, which may be a converter alone, an inverter alone, or an integrated converter and inverter. The housing 11 is made of a highly insulating (non-conductive) material. Examples of insulating materials include plastic, urethane, glass, porcelain, fine ceramics, vinyl, rubber, wood, and paper. The housing 11 may have openings for passing electrical wiring, terminals, etc.

[0014] Generally, a motor drive device 1 is provided with an inverter corresponding to each drive shaft. Furthermore, in order to reduce the cost and space occupied by the motor drive device 1, one converter is often connected to multiple inverters via a DC link. In the illustrated example, as an example, two housings 11 are provided adjacent to each other along the X-axis direction. Hereinafter, the reference numerals for the two adjacent housings 11 may be separately designated as 11-1 and 11-2, and the housings 11-1 and 11-2 may be collectively referred to as the housing 11. In the following description, as an example, the housing 11-1 houses a converter and the housing 11-2 houses an inverter. However, the types of power conversion devices housed in the housings 11-1 and 11-2 do not limit this embodiment. For example, the housing 11-1 may house an inverter, and the housing 11-2 may house a converter. Furthermore, the number of adjacent housings 11 is not limited to two and may be three or more.

[0015] A bus bar 12 is used to electrically connect DC terminals of power conversion devices provided in adjacent housings 11 (housings 11-1 and 11-2 in FIG. 1 ) to a DC link. The bus bar 12 is made of metal such as copper, brass, or aluminum. The bus bar 12 is, for example, a thin, substantially straight, rod-shaped metal sheet. The bus bar 12 is manufactured, for example, by sheet metal processing.

[0016] The DC power lines constituting the DC link include a positive power line and a negative power line. The bus bar 12 constituting the positive power line of the DC link is referred to as a positive bus bar 12P. The bus bar 12 constituting the negative power line of the DC link is referred to as a negative bus bar 12N. Hereinafter, the positive bus bar 12P and the negative bus bar 12N may be collectively referred to as bus bar 12. Therefore, the bus bar 12 refers to the positive bus bar 12P, the negative bus bar 12N, or both the positive bus bar 12P and the negative bus bar 12N. The positive bus bar 12P is used to electrically connect the positive DC terminal of the power conversion device (i.e., the positive DC output terminal of the converter and / or the positive DC input terminal of the inverter) to the positive power line of the DC link. The negative bus bar 12N is used to electrically connect the negative DC terminal of the power conversion device (i.e., the negative DC output terminal of the converter and / or the negative DC input terminal of the inverter) to the negative power line of the DC link. The positive bus bar 12P and the negative bus bar 12N have the same shape and structure.

[0017] A connector 13 is provided on a surface of the housing 11 that corresponds to the "front" of the motor drive device 1, for connecting the power conversion device in the housing 11 to a DC link using a bus bar 12. The connector 13 has a structure that allows the bus bar 12 to be inserted and removed. FIG. 1 shows a state in which the bus bar 12 has already been inserted (attached) into the connector 13. The connector 13 is mounted on a printed circuit board, and the printed circuit board on which the connector 13 is mounted is installed in the housing 11. At this time, the connector 13 is mounted on the housing 11 via the printed circuit board so that the insertion and removal direction of the bus bar 12 relative to the connector 13 (the Y-axis direction) is approximately perpendicular to the mounting surface of the connector 13 relative to the housing 11.

[0018] The connector 13 is configured as a floating connector in which the busbar 12 moves relative to the connector 13 due to elastic deformation that occurs when the busbar 12 is inserted. That is, the connector 13 has a plurality of contacts 31 that elastically deform when the busbar 12 is inserted and make physical and electrical contact with the busbar 12. These contacts 31 are arranged side by side in a direction substantially the same as the longitudinal direction of the inserted busbar 12. When the motor drive device 1 is viewed from the front (i.e., from the negative Y-axis direction), the contacts 31 of the connector 13 are exposed. The contacts 31 of the connector 13 are further electrically connected to DC terminals (not shown) of a power conversion device in the housing 11 in which the connector 13 is installed. The connector 13 also has an insulating contact protector 32 that covers the contacts 31 so that the contacts 31 are exposed in the insertion / removal direction of the busbar 12 relative to the connector 13 (the Y-axis direction). Details of the contact protector 32 will be described later.

[0019] The connector 13 into which the positive bus bar 12P used to connect the positive power line of the DC link can be inserted and removed is referred to as the positive connector 13P. The connector 13 into which the negative bus bar 12N used to connect the negative power line of the DC link can be inserted and removed is referred to as the negative connector 13N. Hereinafter, the positive connector 13P and the negative connector 13N may be collectively referred to as the connector 13. Therefore, the connector 13 refers to the positive connector 13P, the negative connector 13N, or both the positive connector 13P and the negative connector 13N. The positive connector 13P and the negative connector 13N have the same shape and structure. The positive connector 13P is used to electrically connect the positive DC terminal of the power conversion device (i.e., the positive DC output terminal of the converter and / or the positive DC input terminal of the inverter) to the positive bus bar 12P. The negative connector 13N is used to electrically connect the negative DC terminal of the power conversion device (i.e., the negative DC output terminal of the converter and / or the negative DC input terminal of the inverter) to the negative bus bar 12N.

[0020] A positive connector 13P and a negative connector 13N are provided on the surface of housing 11-1 corresponding to the "front" of motor drive device 1, for connecting the DC output terminal of the converter in housing 11-1 to a DC link using a positive bus bar 12P and a negative bus bar 12N. Similarly, a positive connector 13P and a negative connector 13N are provided on the surface of housing 11-2 corresponding to the "front" of motor drive device 1, for connecting the DC input terminal of the inverter in housing 11-2 to a DC link using a positive bus bar 12P and a negative bus bar 12N.

[0021] A plurality of housings 11 (in the example shown in FIG. 1 , housings 11-1 and 11-2) are arranged adjacent to each other in one direction. A connector 13 is provided on each of the plurality of housings 11 so that a rod-shaped bus bar 12 can be simultaneously inserted into each of the connectors 13 provided on the plurality of housings 11. The connectors 13 provided on each of the plurality of housings 11 have the same shape and structure. When these housings 11 are arranged adjacent to each other, the mounting surfaces of the connectors 13 for each of the plurality of housings 11 form approximately the same plane. By setting the mounting surfaces of the connectors 13 for each of the plurality of housings 11 to be positioned approximately on the same plane, the bus bar 12 can be simultaneously inserted into each of the connectors 13 provided on the plurality of housings 11. In the example shown in FIG. 1 , the connectors 13 are mounted on the housings 11 so that the Y coordinate values ​​of the connectors 13 provided on adjacent housings 11 are approximately the same in an XYZ coordinate system. Here, an example in which the number of adjacent housings 11 is two has been described, but the same applies to the case in which three or more housings 11 are adjacent.

[0022] FIG. 2 is a circuit diagram of the motor drive device shown in FIG.

[0023] In FIG. 1 , a positive bus bar 12P is inserted into a positive connector 13P provided on a housing 11-1 housing the converter and a positive connector 13P provided on a housing 11-2 housing the inverter. A negative bus bar 12N is inserted into a negative connector 13N provided on a housing 11-1 housing the converter and a negative connector 13N provided on a housing 11-2 housing the inverter. The converter housed in the housing 11-1 shown in FIG. 1 is indicated by reference numeral 200 in FIG. 2 . The inverter housed in the housing 11-2 shown in FIG. 1 is indicated by reference numeral 300 in FIG. 2 . By inserting the positive bus bar 12P and the negative bus bar 12N into the positive connector 13P and the negative connector 13N as shown in FIG. 1 , the DC output terminal of the converter 200 and the DC input terminal of the inverter 300 are connected via a DC link as shown in FIG. 2 .

[0024] The converter 200 converts AC power supplied from the AC power source 100 into DC power and outputs the DC power to a DC link. The converter 200 is configured as a three-phase bridge circuit when three-phase AC power is supplied from the AC power source 100, and as a single-phase bridge circuit when single-phase AC power is supplied from the AC power source 100. Examples of the converter 200 include a diode rectifier, a 120-degree conduction rectifier, and a PWM switching control rectifier. For example, when the converter 200 is configured as a 120-degree conduction rectifier or a PWM switching control rectifier, the converter 200 is configured as a bridge circuit of switching elements and diodes connected in reverse parallel to the switching elements. The switching elements are controlled to be on and off in response to drive commands received from a higher-level control device (not shown), thereby performing bidirectional AC / DC power conversion. In this case, examples of the switching elements include field-effect transistors (FETs), insulated gate bipolar transistors (IGBTs), thyristors, gate-to-gate (GTOs), and transistors, but other semiconductor elements may also be used. An AC reactor, an AC line filter, and the like may be provided on the AC input side of the converter 200, but these are not shown here.

[0025] The inverter 300 converts DC power in the DC link into AC power for driving the motor and outputs it to the motor 400. The inverter 300 may be configured to convert DC power into AC current, such as a PWM-controlled inverter with internal switching elements. The inverter 300 is configured as a three-phase bridge circuit when the motor 400 is a three-phase AC motor, and as a single-phase bridge circuit when the motor 400 is a single-phase motor. In the illustrated example, the motor 400 is a three-phase AC motor, so the inverter 300 is configured as a three-phase bridge circuit. When the inverter 300 is configured as a PWM-controlled inverter, it is configured as a bridge circuit of diodes and switching elements connected in antiparallel to the diodes. In this case, examples of the switching elements include FETs, IGBTs, thyristors, GTOs, and transistors, but other semiconductor elements may also be used. The inverter 300 converts DC power in the DC link into AC power for driving the motor and outputs it by PWM-controlled on / off operation of the internal switching elements based on commands from a host control device (not shown). The speed, torque, or rotor position of the motor 400 is controlled based on the AC power supplied from the inverter 300. Note that the inverter 300 can also convert the AC power regenerated by the motor 400 into DC power and return it to the DC link on the DC side by appropriately PWM-controlling the on / off operation of the switching elements.

[0026] A DC link capacitor is provided in the DC link connecting the DC output terminal of the converter 200 and the DC input terminal of the inverter 300, but is not shown in FIG. 2 . The DC link capacitor has the function of storing DC power used by the inverter 300 to generate AC power and the function of suppressing pulsation in the DC output of the converter 200. Examples of the DC link capacitor include an electrolytic capacitor and a film capacitor. The DC link capacitor is provided either inside the housing 11-1, inside the housing 11-2, or outside the housings 11-1 and 11-2.

[0027] <Configuration of connector according to embodiment of the present disclosure> Figures 6 and 8 to 10 are perspective views of a connector provided in the housing of a motor drive device according to an embodiment of the present disclosure. Figure 7 is a front view of a connector provided in the housing of a motor drive device according to an embodiment of the present disclosure. Figure 11 is a side view of a connector provided in the housing of a motor drive device according to an embodiment of the present disclosure.

[0028] The connector 13 is a floating connector in which the busbar 12 moves relative to the connector 13 due to elastic deformation that occurs when the busbar 12 is inserted. That is, the connector 13 has a plurality of elastically deformable contacts 31. When the motor drive device 1 is viewed from the front (i.e., from the negative side in the Y-axis direction), the plurality of contacts 31 are exposed. When the busbar 12 is inserted, each of the plurality of contacts 31 elastically deforms to come into physical and electrical contact with the busbar 12. The plurality of contacts 31 are arranged side by side in approximately the same direction as the longitudinal direction of the inserted busbar 12. The juxtaposed contacts 31 are provided in two rows, and these two rows face each other. When the busbar 12 is inserted into the connector 13, the busbar 12 is sandwiched between the two rows of the elastically deformed plurality of contacts 31 while making physical and electrical contact with the busbar 12.

[0029] The connector 13 is provided with a contact protection section 32 to prevent a human finger from coming into contact with the contact 31 and causing an electric shock, or another conductive member from coming into contact with the contact 31 and causing a current leak. The contact protection section 32 opens toward the insertion / removal direction of the bus bar 12 relative to the connector 13 (the negative Y-axis direction), and covers the contact 31 so that the contact 31 is exposed toward the insertion / removal direction of the bus bar 12 relative to the connector 13 (the negative Y-axis direction). The contact 31 is provided at a position recessed toward the positive Y-axis direction from the end face of the opening of the contact protection section 32 that faces the insertion / removal direction of the bus bar 12 (the negative Y-axis direction). The contact protection section 32 is structured so that a human finger will not come into contact with the contact 31 even if the human finger is inserted into the connector 13 from the insertion direction side of the bus bar 12 (the negative Y-axis side). For example, the width of the opening of the contact protection part 32 in the Z-axis direction (the short side direction of the bus bar 12) facing the insertion / removal direction of the bus bar 12 (the negative Y-axis direction) is set to be smaller than the thickness of a human finger and larger than the width of the bus bar 12 in the Z-axis direction. The contact protection part 32 is made of a highly insulating material. Examples of insulating materials include plastic, urethane, glass, porcelain, fine ceramics, vinyl, rubber, wood, and paper.

[0030] <Configuration of Bus Bar According to Embodiment of Present Disclosure> FIG. 12 is a perspective view of a bus bar used for DC link connection of a motor drive device according to an embodiment of the present disclosure.

[0031] The busbar 12 is made of a metal such as copper, brass, or aluminum. The busbar 12 is, for example, a thin, linear, rod-shaped metal sheet and has a substantially rectangular parallelepiped shape. The longitudinal direction (X-axis direction) of the busbar 12 substantially coincides with the arrangement direction of the multiple contacts 31 in the connector 13. The lateral direction (Y-axis direction) of the busbar 12 substantially coincides with the insertion / removal direction of the busbar 12 relative to the connector 13. The length of the busbar 12 in the Z-axis direction is shorter than the length of the busbar 12 in the Y-axis direction. The length of the busbar 12 in the Z-axis direction is, for example, approximately 3 mm. Note that the values ​​given here are merely examples and other values ​​may be used. As will be described later, the length of the busbar 12 in the longitudinal direction (X-axis direction) is set to be shorter than the width of one housing 11 in the X-axis direction when multiple housings 11 are arranged adjacent to each other along the X-axis direction.

[0032] <Configuration of Support Base According to Embodiment of the Present Disclosure> Fig. 14 is a perspective view of a support base that supports a bus bar used for DC link connection of a motor drive device according to an embodiment of the present disclosure. Figs. 13 and 15 are perspective views of the bus bar and support base used for DC link connection of a motor drive device according to an embodiment of the present disclosure.

[0033] The larger the exposed area of ​​the busbar 12 through which a large current flows, the greater the possibility of a person receiving an electric shock when coming into contact with the busbar 12, or of another conductive member coming into contact with the busbar 12 and causing a current leak. Furthermore, the busbar 12 inserted into the connector 13 may become dislodged due to vibration of the housing 11. Furthermore, since the busbar 12 is a thin, rod-shaped, approximately straight metal plate, handling the busbar 12 can be somewhat inconvenient. To eliminate these problems, it is preferable to attach a support base 14 to the busbar 12.

[0034] The support base 14 supports the bus bar 12. The support base 14 has a latch mechanism 21 and a bus bar protective cover 22. The latch mechanism 21 and the bus bar protective cover 22 are integrally molded. The latch mechanism 21 and the bus bar protective cover 22 are made of an insulating material (non-conductive material). Examples of insulating materials include plastic, urethane, glass, porcelain, fine ceramics, vinyl, rubber, wood, and paper.

[0035] The latch mechanism 21 holds the bus bar 12 so that the bus bar 12 is exposed in the insertion direction (positive direction of the Y axis) of the bus bar 12 into the connector 13. In consideration of the ease of the work of attaching the bus bar 12 to the latch mechanism 21, it is preferable that the latch mechanism 21 be made of a flexible member.

[0036] The busbar protective cover 22 opens in the insertion direction of the busbar 12 into the connector 13 (positive direction of the Y axis) and covers the busbar 12 so that the busbar 12 is not exposed in the removal direction of the busbar 12 from the connector 13 (negative direction of the Y axis). The busbar protective cover 22 may also have a surface parallel to the insertion / removal direction of the busbar 12. The busbar protective cover 22 can prevent electric shock caused by a person touching the busbar 12 and electric leakage caused by another conductive member coming into contact with the busbar 12. Note that in order to improve the insertion / removal operation of the busbar 12 into / from the connector 13, the busbar protective cover 22 may be provided with a recess so that a person's fingers can fit into the recess and grip the busbar protective cover 22.

[0037] <Attachment of bus bar and connector according to an embodiment of the present disclosure>

[0038] Fig. 16 is a front view of a connector into which a bus bar is inserted in a motor drive device according to an embodiment of the present disclosure. Fig. 17 is a side view of a connector into which a bus bar is inserted in a motor drive device according to an embodiment of the present disclosure. Fig. 18 is a perspective view of a connector into which a bus bar is inserted in a motor drive device according to an embodiment of the present disclosure. In Figs. 16 to 18, the support base 14 is not shown to make it easier to see the attachment state of the bus bar 12 and the connector 13, but the support base 14 may be attached to the bus bar 12.

[0039] When bus bar 12 is inserted into connector 13 from the negative direction of the Y-axis toward the positive direction of the Y-axis, the plurality of contacts 31 of connector 13, which is a floating connector, elastically deforms, and bus bar 12 is sandwiched between two rows of the plurality of contacts 31 while maintaining physical and electrical contact. Even if the insertion direction or insertion position of bus bar 12 is slightly misaligned with respect to connector 13, the elastic deformation of contacts 31 ensures stable physical and electrical contact between bus bar 12 and contacts 31.

[0040] FIG. 19 is a front view illustrating a state in which the bus bar with the support base attached thereto is inserted into the connector in the motor drive device according to the embodiment of the present disclosure.

[0041] 19 shows the "front" of the motor drive device 1 as viewed from the negative side in the Y-axis direction. The busbar protective cover 22 of the support base 14 covers the busbar 12 so that the busbar 12 is not exposed in the direction in which the busbar 12 is removed from the connector 13 (the negative side in the Y-axis direction), and therefore the busbar 12 cannot be seen from the negative side in the Y-axis direction. The busbar protective cover 22 of the support base 14 prevents electric shock caused by a person touching the busbar 12 and electric leakage caused by other conductive members coming into contact with the busbar 12.

[0042] <Size Relationship Between Bus Bar and Housing According to an Embodiment of the Present Disclosure> FIG. 20 is a front view showing the size relationship between the housing and the bus bar in a motor drive device according to an embodiment of the present disclosure.

[0043] The length of the bus bar 12 in the longitudinal direction (X-axis direction) is LB, and the length of each of the housings 11-1 and 11-2 in the X-axis direction is LH. The longitudinal direction of the bus bar 12 substantially coincides with the direction in which the housings 11-1 and 11-2 are arranged side by side. The length LB of the bus bar 12 in the longitudinal direction (X-axis direction) is set to be shorter than the length LH of the housing 11 in the X-axis direction. Note that if the lengths of the housings 11-1 and 11-2 in the X-axis direction are different, the length LH of the housing 11 in the X-axis direction that is the shorter length is used as LH.

[0044] By inserting the bus bar 12 so as to straddle the connectors 13 provided on each of the adjacent housings 11-1 and 11-2, the power conversion devices in the housings 11-1 and 11-2 can be connected to the DC link. In the example shown in Figure 20, there are two housings 11, but even if there are three or more housings 11, the power conversion devices in the housings 11 can be connected to the DC link by connecting the bus bars 12 in the same way. If there are housings 11 with different lengths in the X-axis direction among the three or more housings 11, the length in the X-axis direction of the housing 11 with the shortest length in the X-axis direction is used as LH.

[0045] By setting the size relationship between the bus bars 12 and the housings 11 as described above, it is possible to achieve scalability that allows bus bars 12 of the same standard to accommodate various numbers of housings 11. Furthermore, because the standard of the bus bars 12 can be unified, it is possible to reduce the number of types of bus bars 12 in stock, and as a result, the manufacturing cost of the motor drive device 1 can be reduced.

[0046] Advantages of the Embodiments of the Present Disclosure According to the embodiments of the present disclosure, it is possible to realize a motor drive device having a DC link connection that is easy to assemble.

[0047] Because a relatively large current flows through the power elements of the power conversion devices (converters and inverters) in a motor drive device, bus bars are often used to electrically connect the power conversion devices to a DC link. Conventionally, a DC link has been constructed by providing a terminal block for each power conversion device and fastening the bus bar to the terminal block with screws. However, the time-consuming and labor-intensive process of tightening and loosening the screws increases the assembly time and cost of the motor drive device. Furthermore, considering the ease of tightening and loosening the screws, the terminal block must be enlarged, resulting in a problem of an increased size of the motor drive device.

[0048] In contrast, according to an embodiment of the present disclosure, a connector is mounted on a housing that houses a power conversion device. The mounting surfaces of the connectors on the housings are set to be substantially flush with each other between adjacent housings. This allows a DC link to be formed simply by inserting a bus bar into a connector electrically connected to the power conversion device. This facilitates assembly of the motor drive device, thereby reducing assembly time and assembly costs. Furthermore, since the embodiment of the present disclosure does not use a bulky terminal block, the motor drive device can be made more compact. Furthermore, according to an embodiment of the present disclosure, the connector is mounted on the housing so that the insertion and removal direction of the bus bar into and from the connector is substantially perpendicular to the mounting surface of the connector on the housing. By setting the mounting surface of the connector on the housing as the surface that allows the easiest and most efficient access to the motor drive device for workers performing maintenance work and various operations, the insertion and removal of the bus bar into and from the connector is facilitated.

[0049] Furthermore, according to an embodiment of the present disclosure, the connector is configured as a floating connector having contacts that make physical and electrical contact with the bus bar while elastically deforming when the bus bar is inserted, thereby ensuring more reliable physical and electrical contact between the bus bar and the connector contacts even if the insertion direction or position of the bus bar is slightly misaligned with respect to the connector.

[0050] According to an embodiment of the present disclosure, the connector may be provided with a contact protection part, which can prevent a human finger from coming into contact with the connector contacts and causing an electric shock, or prevent other conductive members from coming into contact with the connector contacts and causing a current leak.

[0051] Furthermore, according to an embodiment of the present disclosure, the longitudinal length of the bus bar is set to be shorter than the width of one of the housings when multiple housings are arranged adjacent to each other along the same direction. This allows for scalability to accommodate various numbers of housings using bus bars of the same standard. Furthermore, because the bus bar standards can be standardized, the number of bus bar varieties in stock can be reduced, resulting in reduced manufacturing costs for motor drive devices.

[0052] According to an embodiment of the present disclosure, a support base may be attached to the bus bar. A bus bar protective cover attached to the support base can prevent electric shock caused by a person touching the bus bar and electric leakage caused by contacting the bus bar with other conductive members. A latch mechanism attached to the support base can prevent the bus bar inserted into the connector from coming off due to vibration of the housing.

[0053] Although the present disclosure has been described in detail above, the present disclosure is not limited to the individual embodiments and individual variations described above. Various additions, substitutions, modifications, partial deletions, etc. are possible for these embodiments and variations within the scope of the gist of the present disclosure, or within the scope of the gist of the present disclosure derived from the content of the claims and their equivalents. These embodiments and variations can also be implemented in combination. For example, in the above-described embodiments and variations, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical formulas are used in the description of the above-described embodiments and variations.

[0054] <Supplementary Notes> The following supplementary notes are further disclosed regarding the above-described embodiment and modifications.

[0055] (Supplementary Note 1) A motor drive device 1 comprises: housings 11, 11-1, and 11-2 that house a power conversion device including at least one of a converter 200 that converts AC power supplied from an AC power supply 100 into DC power and an inverter 300 that converts DC power supplied from the converter 200 via a DC link into AC power for driving a motor; a bus bar 12 that electrically connects the power conversion device to the DC link; and a connector 13 that connects the bus bar 12 to the power conversion device when the bus bar 12 is inserted, wherein the connector 13 is mounted on the housings 11, 11-1, and 11-2 so that the insertion and removal direction of the bus bar 12 with respect to the connector 13 is approximately perpendicular to the mounting surface of the connector 13 on the housings 11, 11-1, and 11-2. (Supplementary Note 2) The motor drive device 1 according to Supplementary Note 1, wherein the busbar 12 includes a positive busbar 12P for electrically connecting a positive terminal of the power conversion device to a positive power line of the DC link and a negative busbar 12N for electrically connecting a negative terminal of the power conversion device to a negative power line of the DC link, and the connector 13 includes a positive connector 13P into which the positive busbar 12P can be inserted and a negative connector 13N into which the negative busbar 12N can be inserted and removed. (Supplementary Note 3) The motor drive device 1 according to Supplementary Note 1, further comprising a support base 14 for supporting the busbar 12, wherein the support base 14 has: a latch mechanism 21 for holding the busbar 12 so that the busbar 12 is exposed in the direction of inserting the busbar 12 into the connector 13; and an insulating busbar protective cover 22 for covering the busbar 12 so that the busbar 12 is not exposed in the direction of removing the busbar 12 from the connector 13. (Supplementary Note 4) The motor drive device 1 according to Supplementary Note 1, wherein the longitudinal length LB of the bus bar 12 is shorter than the width LH in one direction of one of the housings 11, 11-1, and 11-2 when the housings 11, 11-1, and 11-2 are arranged side by side adjacent to each other in one direction. (Supplementary Note 5) The motor drive device 1 according to Supplementary Note 1, wherein the connector 13 is mounted on each of the housings 11, 11-1, and 11-2 so that the substantially linear bus bar 12 can be inserted simultaneously when the housings 11, 11-1, and 11-2 are arranged side by side adjacent to each other in one direction.(Supplementary Note 6) The motor drive device 1 according to Supplementary Note 1, wherein the connector 13 is a floating connector that elastically deforms when the bus bar 12 is inserted, causing the bus bar 12 to move relative to the connector 13. (Supplementary Note 7) The motor drive device 1 according to Supplementary Note 6, wherein the connector 13 has contacts 31 that elastically deform when the bus bar 12 is inserted and make electrical contact with the bus bar 12. (Supplementary Note 8) The motor drive device 1 according to Supplementary Note 7, wherein a plurality of contacts 31 are arranged side by side in substantially the same direction as the longitudinal direction of the inserted bus bar 12. (Supplementary Note 9) The motor drive device 1 according to Supplementary Note 7, wherein the connector 13 has insulating contact protectors 32 that cover the contacts 31 so that the contacts are exposed in the direction of insertion and removal of the bus bar 12 into and from the connector 13.

[0056] REFERENCE SIGNS LIST 1 motor drive device 11, 11-1, 11-2 housing 12 bus bar 12N negative side bus bar 12P positive side bus bar 13 connector 13N negative side connector 13P positive side connector 14 support base 21 latch mechanism 22 bus bar protection cover 31 contact 32 contact protection unit 100 AC power supply 200 converter 300 inverter 400 motor

Claims

1. A motor drive device comprising a housing that houses a power conversion device including at least one of a converter that converts AC power supplied from an AC power source into DC power and an inverter that converts DC power supplied from the converter via a DC link into AC power for driving a motor, a bus bar for electrically connecting the power conversion device to the DC link, and a connector for conducting the bus bar with the power conversion device when the bus bar is inserted, wherein the connector is mounted on the housing such that an insertion / removal direction of the bus bar with respect to the connector is substantially perpendicular to a mounting surface of the connector with respect to the housing.

2. The motor drive device according to claim 1, wherein the bus bar includes a positive bus bar for electrically connecting a positive DC terminal of the power conversion device to a positive power line of the DC link and a negative bus bar for electrically connecting a negative DC terminal of the power conversion device to a negative power line of the DC link, and the connector includes a positive connector into which the positive bus bar is insertable / removable and a negative connector into which the negative bus bar is insertable / removable.

3. The motor drive device according to claim 1, further comprising a support base for supporting the bus bar, the support base having a latch mechanism for holding the bus bar such that the bus bar is exposed in an insertion direction of the bus bar with respect to the connector and an insulating bus bar protection cover for covering the bus bar such that the bus bar is not exposed in a removal direction of the bus bar with respect to the connector.

4. The motor drive device according to claim 1, wherein a length in a longitudinal direction of the bus bar is shorter than a width in one direction of one of the housings when a plurality of the housings are arranged adjacent to each other along one direction.

5. The motor drive device according to claim 1, wherein the connector is mounted on each of the plurality of housings such that the substantially linear bus bar is inserted simultaneously when the plurality of housings are arranged adjacent to each other along one direction.

6. The motor drive device according to claim 1, wherein the connector is a floating connector in which the bus bar is movable relative to the connector due to elastic deformation occurring when the bus bar is inserted.

7. The motor drive device according to claim 6, wherein the connector has a contact that elastically deforms and electrically contacts the bus bar when the bus bar is inserted.

8. The motor drive device according to claim 7, wherein a plurality of the contacts are arranged side by side along a direction substantially the same as the longitudinal direction of the bus bar to be inserted.

9. The motor drive device according to claim 7, wherein the connector has an insulating contact protection portion that covers the contacts so that the contacts are exposed in the insertion and removal direction of the bus bar with respect to the connector.

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