CN108630636B

CN108630636B - MOS device mounting structure, controller and electric power steering system

Info

Publication number: CN108630636B
Application number: CN201710184061.1A
Authority: CN
Inventors: 吴凯; 董健; 付军
Original assignee: Johnson Electric Shenzhen Co Ltd
Current assignee: Johnson Electric Shenzhen Co Ltd
Priority date: 2017-03-24
Filing date: 2017-03-24
Publication date: 2022-01-14
Anticipated expiration: 2037-03-24
Also published as: CN108630636A

Abstract

The invention provides an MOS device mounting structure, a controller using the same and an electronic power steering system. The invention can save the installation space of the MOS device, accelerate the heat dissipation and reduce the interference of the MOS device on other electronic elements.

Description

MOS device mounting structure, controller and electric power steering system

[ technical field ] A method for producing a semiconductor device

The present invention relates to a MOS device mounting structure, a controller using the MOS device mounting structure, and an electric power steering system using the controller.

[ background of the invention ]

Electric actuators typically require the use of a large number of MOS transistors. For example, the electric power steering system generally needs high safety performance to ensure the safety of driving, and therefore, the electric power steering system generally further includes a fail-safe device. Therefore, except 6 MOS transistors needed in a motor driving circuit, the automatic fault-prevention device started by the electronic power-assisted steering system further comprises 3-5 MOS transistors, the MOS transistors with large quantity need larger installation space, and in addition, the heat dissipation problem of the MOS transistors needs to be solved because the heat productivity of the MOS transistors is large. Furthermore, it is also considered that the MOS transistor generates signal interference to other electronic components.

Therefore, how to provide a compact mounting structure for MOS devices, or even how to solve the problem of heat dissipation of MOS transistors and the interference of signals generated to other electronic components at the same time, is a problem to be solved.

[ summary of the invention ]

In view of this, the present invention provides a MOS device mounting structure, which includes a heat sink, the heat sink is provided with at least one accommodating cavity, the accommodating cavity is used for accommodating a pair of MOS devices, and the MOS devices are attached to the side walls of the accommodating cavity.

In one embodiment, the MOS device mounting structure further includes at least one pressing member, and the MOS device is pressed by the pressing member to be attached to the side wall of the accommodating cavity.

In one embodiment, a pair of MOS devices accommodated in the same accommodating cavity is simultaneously pressed by a pressing member to be attached to the side wall of the accommodating cavity.

In one embodiment, the pair of MOS devices are disposed in the accommodating cavity in a face-to-face manner.

In one embodiment, one surface of the MOS device, which is attached to the side wall of the accommodating cavity, is electrically insulated from the heat sink by an insulator.

In one embodiment, the MOS device is electrically insulated from other conductive members by an insulator, except for a conductive terminal.

In one embodiment, the insulator may be an insulating paste, an insulating film, or an aluminum-based circuit board.

In one embodiment, the receiving cavity includes an opening through which the terminal of the MOS device protrudes from the receiving cavity.

In one embodiment, the pressing member is an elastic member, two ends of the elastic member respectively abut against the pair of MOS devices, and a middle section of the elastic member is compressed to provide pushing force to the two ends.

In one embodiment, a mounting rack is disposed in each receiving cavity, and the mounting rack is used for mounting the pair of MOS devices in the receiving cavities.

In one embodiment, the mounting frame includes a receiving groove, the receiving groove penetrates through two end portions of the mounting frame, the pair of MOS devices are respectively disposed at two end portions of the receiving groove of the mounting frame, and the pressing member is disposed in a middle portion of the receiving groove to abut against the pair of MOS devices toward two sides.

In one embodiment, the receiving groove of the mounting frame is divided into three compartments communicating with each other by two partitions, the pair of MOS devices are respectively located in the compartments at both ends, and the pressing member is disposed in the middle compartment.

In one embodiment, the heat sink further includes a plurality of second receiving cavities, each of the second receiving cavities is configured to receive an MOS device, and a second pressing member is disposed in each of the second receiving cavities, and the second pressing member abuts against the MOS device to make the MOS device adhere to a sidewall of the second receiving cavity.

The invention also provides a controller, which comprises the MOS device mounting structure, a shell and a control part, wherein the radiator and the shell jointly form an accommodating space for accommodating the control part.

In one embodiment, the control portion includes a signal board and a power board, and the terminals of the pair of MOS devices are electrically connected to the power board.

In one embodiment, the source of one of the pair of MOS devices is short-circuited to the drain of the other of the pair of MOS devices by a conductive strip, and the other terminals of the pair of MOS devices are electrically connected to the power supply board.

In one embodiment, the conductive sheet is a metal sheet.

In one embodiment, the signal plate is stacked on the power supply plate, and the signal plate and the power supply plate are electrically connected through a frequency pin.

In one embodiment, a motor driving circuit is disposed on the power board, and the pair of MOS devices are switching elements in the motor driving circuit.

In one embodiment, the motor driving circuit is a three-phase six-bridge circuit, and the pair of MOS devices form upper and lower bridge arms of one phase.

In one embodiment, the mobile terminal further includes a plurality of input interfaces and output interfaces, the input interfaces are input interfaces of power supply or/and signals, and the output interfaces are output interfaces of power supply or/and signals.

The invention also provides an electric power steering system which comprises the controller.

In one embodiment, the control portion includes a fail-safe device, and the MOS device accommodated in the second accommodating chamber is a switching element on the fail-safe device.

The invention can save the installation space of the MOS device, accelerate the dissipation of MOS generated heat and reduce the interference of the MOS device on other electronic elements.

[ description of the drawings ]

The invention will be further explained by the accompanying drawings and examples.

FIG. 1 is a schematic perspective view of a controller according to one embodiment of the present invention;

FIG. 2 is a schematic perspective view of the controller of FIG. 1 from another angle;

FIG. 3 is an exploded schematic view of the controller shown in FIG. 1;

FIG. 4 is an exploded view of the controller of FIG. 1 from another perspective;

fig. 5 is an exploded schematic view of a MOS device mounting structure of the controller shown in fig. 1.

[ detailed description ] embodiments

Various embodiments of the present invention will be described with reference to the accompanying drawings. In the specification and drawings, elements having similar structures or functions will be denoted by the same reference numerals. It is to be understood that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention. The dimensions shown in the figures are for clarity of description only and are not intended to be limiting, nor are they intended to be exhaustive or to limit the scope of the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It will be understood that when an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements may also be present. When a component is referred to as being "disposed on" another component, it can be directly on the other component or intervening components may also be present. As used herein, the term "or/and" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1-4, a controller 10 according to an embodiment of the present invention is shown. The controller 10 includes a control portion 20 and a heat dissipation portion 30. The heat radiating portion 30 includes a heat sink 31 for radiating heat to the control portion 20. The heat sink 31 and a housing 40 together form a receiving space 50 for receiving the control portion 20. A plurality of input/output interfaces 32 are formed on the heat sink 31, and the input/output interfaces 32 may be power or/and signal input/output interfaces. In other embodiments, the input or/and output interfaces may be formed partially or entirely on the housing 40.

The control part 20 comprises a signal plate 21 and a power supply plate 22, wherein the signal plate 21 is superposed on the power supply plate 22 and is electrically connected with the power supply plate 22 through a frequency pin. The signal board 21 is a Printed Circuit Board (PCB). The power board 22 includes a support 221, and a plurality of electronic components electrically connected to a circuit on the support 221, wherein the electronic components include a plurality of MOSFETs 222(Metal Oxide Semiconductor field effect transistors, hereinafter referred to as MOS devices 222).

Referring to fig. 5, in an embodiment in which the controller 10 is applied to an electric power steering system, the MOS devices 222 include 3 pairs of MOS devices used as switching elements in a motor driving circuit and 3 MOS devices used as switching elements in a fail-safe apparatus. The control section 20 includes the motor drive circuit and a fail-safe device. The 9 MOS devices 222 are all disposed in the accommodating cavity 311 formed on the heat sink 31, and directly contact with the sidewall of the accommodating cavity 311 to dissipate heat. Specifically, 6 receiving cavities 311 are formed at the bottom of the heat sink 31, and the receiving cavities 311 are communicated with the receiving space 50 through openings 3111 thereof. Each of the three accommodating cavities 311a is configured to accommodate a pair of MOS devices 222, where the pair of MOS devices 222 may be two MOS devices of an upper bridge arm and a lower bridge arm of one phase in a three-phase six-bridge motor driving circuit. Each of the other three receiving cavities 311b is for receiving one MOS device 222, and the one MOS device 222 is a MOS device in the fail-safe apparatus. The MOS device 222 is placed in the accommodating cavity 311 and is attached to the sidewall of the accommodating cavity 311. In the illustrated embodiment, after being received in the receiving cavity 311, an end of the MOS device 222 where the terminal 2221 is located faces or protrudes out of the opening 3111, the terminal 2221 extends into the receiving space 50, and all or a part of the terminal 2221 is electrically connected to the power board 22 received in the receiving space 50, and specifically, all or a part of the terminal 2221 is electrically connected to some position of the motor driving circuit on the power board 22. In one embodiment, the terminals 2221 for the three MOS devices 222 in the fail-safe apparatus are all electrically connected to the power supply board 22, while the terminals 2221 for the 3 pairs of MOS devices 222 in the motor drive circuit are electrically connected to the power supply board 22 except that the source of one is directly short-circuited to the drain of the other by a conductive sheet (e.g., a metal sheet). By directly connecting the source of one of the pair of MOS devices 222 to the drain of the other by a conductive plate, the circuit impedance can be reduced compared to a conventional case where all terminals are connected to a power board and then electrically connected by a circuit on the power board. The terminal 2221 may be electrically connected to the power supply board 22 by soldering.

In the illustrated embodiment, the MOS device 222 is mounted in the receiving cavity 311 through a mounting bracket 60. Each of the mounting frames 60a is used for mounting a pair of MOS devices 222 in the receiving cavity 311a, and each of the mounting frames 60b is used for mounting one MOS device 222 in the receiving cavity 311 b. A receiving groove 601 is formed in each mounting bracket 60, and the receiving groove 601 extends from one end of the mounting bracket 60a to the other end thereof, so as to penetrate through the mounting bracket 60 a. In this embodiment, the mounting bracket 60 is substantially U-shaped. After being placed in the accommodating cavity 311, two sides of the mounting bracket 60a, which are communicated by the accommodating groove, are attached to or close to the side wall of the accommodating cavity 311, and the top opening 6011 of the accommodating groove 601 corresponds to the opening 3111 of the accommodating cavity 311 a. The two MOS devices 222 are respectively disposed on two sides of the accommodating groove through the opening 3111 of the accommodating groove 601, and are attached to the sidewall of the accommodating cavity 311 to dissipate heat through the heat sink 31. An insulator is provided on the side of the MOS device 222 attached to the heat sink 31 to electrically insulate the heat sink 31. The insulator can be an insulating glue coated on the MOS device, an insulating film wrapped on the MOS device or an aluminum-based circuit board arranged on one side of the MOS device. In yet another embodiment, the MOS device 222 may be electrically insulated from other conductive components by a wrapping insulating glue, an insulating film or an aluminum-based circuit board, except for the base, the source and the drain which need to be electrically connected with other conductive components.

Specifically, the bottom of the receiving groove 601 has a stepped structure matching with the MOS devices 222, and in addition, the receiving groove 601 is divided into three mutually communicated compartments by two partition members 602 along a direction that the receiving groove 601 penetrates through the mounting frame 60a, the two MOS devices 222 are respectively located in the compartments at two ends, and the middle compartment is used for receiving a pressing member 70. The pressing member 70 provides a pushing force to the two MOS devices 222 to fit the two MOS devices to the side wall of the receiving cavity 311. In the illustrated embodiment, the pressing member 70 is an elastic member, two ends of which respectively abut against the two MOS devices 222, and a middle section of which is compressed to provide a pushing force against two ends of the MOS devices 222.

The mounting block 60b has substantially the same structure as the mounting block 60a, except that the receiving groove 601 of the mounting block 60b is partitioned into two compartments by a partition 602, one compartment for receiving the MOS device 222 and the other compartment for receiving the pressing member 71. The pressing member 71 provides a pushing force to the MOS device 222 to fit the MOS device against the sidewall of the receiving cavity 311. In other embodiments, the receiving grooves of the mounting

frames

60a and 60b are not separated into compartments, and the MOS devices 222 and the

pressing members

70 or 71 are both received in the same space. The

mounts

60a, 60b may be made of an insulating material, such as plastic.

In summary, in the MOS device mounting structure provided in the embodiment of the present invention, the accommodating cavity is disposed on the heat sink, the MOS device is mounted in the accommodating cavity and attached to the heat sink for heat dissipation, and the pair of MOS devices are mounted in the accommodating cavity face to face, which not only saves the mounting space of the MOS device and makes the overall structure of the controller more compact, but also attaches the MOS device to the heat sink for heat dissipation of the MOS device, and the MOS device is far away from the power board and the signal board, thereby reducing electromagnetic interference to other electronic devices.

It will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. The MOS device mounting structure is characterized by comprising a radiator and at least one pressing piece, wherein the radiator is provided with at least one accommodating cavity, the accommodating cavity is used for accommodating a pair of MOS devices, the pair of MOS devices accommodated in the same accommodating cavity are simultaneously pressed and held by the pressing piece so as to be attached to the side wall of the accommodating cavity, the pressing piece is an elastic element, two ends of the elastic element respectively press and hold the pair of MOS devices, and the middle section of the elastic element is compressed so as to provide thrust for the two ends.

2. The MOS device mounting structure of claim 1, wherein the pair of MOS devices are disposed face to face within the receiving cavity.

3. The MOS device mounting structure of claim 1, wherein a surface of the MOS device that abuts the sidewall of the receiving cavity is electrically insulated from the heat sink by an insulator.

4. The MOS device mounting structure of claim 1, wherein the MOS device is electrically insulated from other conductive members by an insulator, except for the conductive terminal.

5. The MOS device mounting structure according to claim 3 or 4, wherein the insulator is an insulating paste, an insulating film, or an aluminum-based circuit board.

6. The MOS device mounting structure of claim 1, wherein the receiving cavity includes an opening through which a terminal of the MOS device extends out of the receiving cavity.

7. The MOS device mounting structure of any one of claims 1-4, wherein a mounting block is disposed in each of the receiving cavities, the mounting block being configured to mount the pair of MOS devices in the receiving cavities.

8. The MOS device mounting structure of claim 7, wherein the mounting frame includes a receiving groove, the receiving groove penetrates through both end portions of the mounting frame, the pair of MOS devices are respectively disposed at both end portions of the mounting frame receiving groove, and the pressing member is disposed at a middle portion of the receiving groove to abut against the pair of MOS devices toward both sides.

9. The MOS device mounting structure of claim 8, wherein the receiving groove of the mounting frame is divided into three compartments communicating with each other by two partitions, the pair of MOS devices are respectively located in the compartments at both ends, and the pressing member is disposed in the compartment in the middle.

10. The mounting structure of a MOS device according to claim 1, wherein the heat sink further includes a plurality of second receiving cavities, each of the second receiving cavities is configured to receive a MOS device, and a second pressing member is disposed in each of the second receiving cavities, and the second pressing member presses the MOS device against a sidewall of the second receiving cavity.

11. A controller, the controller includes a MOS device mounting structure, a housing and a control portion, wherein the MOS device mounting structure is the MOS device mounting structure of any one of claims 1 to 10, and the heat sink and the housing together form a receiving space for receiving the control portion.

12. The controller of claim 11, wherein the control portion includes a signal board and a power board, and terminals of the pair of MOS devices are electrically connected to the power board.

13. The controller of claim 12, wherein a source of one of the pair of MOS devices is short-circuited to a drain of the other of the pair of MOS devices by a conductive pad, and other terminals of the pair of MOS devices are electrically connected to the power supply board.

14. The controller of claim 13, wherein the conductive sheet is a metal sheet.

15. The controller of claim 12, wherein the signal board is stacked on the power board, and the signal board and the power board are electrically connected through a frequency pin.

16. The controller according to claim 12 or 13, wherein a motor driving circuit is provided on the power board, and the pair of MOS devices are switching elements in the motor driving circuit.

17. The controller of claim 16, wherein the motor drive circuit is a three-phase six-bridge circuit, and the pair of MOS devices form upper and lower arms of one of the phases.

18. The controller of claim 11, further comprising a plurality of input interfaces and output interfaces, wherein the input interfaces are input interfaces for power or/and signals, and the output interfaces are output interfaces for power or/and signals.

19. An electric power steering system comprising a controller according to any one of claims 11 to 18.

20. The electric power steering system of claim 19, wherein the control portion includes a fail-safe device, and the MOS device received in the second receiving cavity is a switching element on the fail-safe device.