Search

CN-122029731-A - Electric machine

CN122029731ACN 122029731 ACN122029731 ACN 122029731ACN-122029731-A

Abstract

An electric machine 100 for a motor vehicle includes an electric motor 130 adapted to drive the machine 110. The electric machine 100 further includes an inverter 120 held in an inverter housing 120a, wherein the inverter 120 is adapted to process and regulate power supplied from an external power source to the motor 130. Inverter 120 also includes a printed circuit board 124 and a plurality of power transistors 126 for converting High Voltage (HV) Direct Current (DC) to three-phase Alternating Current (AC) that drives motor 130. In addition, the inverter 120 comprises a frame element 128 fixed to the bottom wall 123 between the printed circuit board 124 and the bottom wall 123, wherein the frame element 128 is formed with a plurality of integrated abutments 128d adapted to push the power transistor 126 with respect to the bottom wall 123.

Inventors

  • P. Ma Taisan
  • F. Abdullah
  • S. Ravichandran
  • A. Dulepandi
  • RAJA ADNAN

Assignees

  • 法雷奥电气化公司

Dates

Publication Date
20260512
Application Date
20241010
Priority Date
20231010

Claims (13)

  1. 1. An electric machine (100), comprising: ● A motor (130); ● -a machine (110) driven by said motor (130); ● An inverter (120), the inverter (120) being housed and held in an inverter housing (120 a) and being adapted to process and regulate electric power supplied to the motor (130) from an external power source, wherein the inverter (120) comprises: o-printed circuit board (124), and O a plurality of power transistors (126) for converting High Voltage (HV) Direct Current (DC) to three-phase Alternating Current (AC) driving the motor (130), Wherein the inverter (120) further comprises a frame element (128), the frame element (128) being fixed to a bottom wall (123) of a front end cap (122) of the inverter housing (120 a), between the printed circuit board (124) and the bottom wall (123), wherein the frame element comprises an integrated pressing portion (128 d), the pressing portion (128 d) being adapted to press the power transistor (126) against the bottom wall (123).
  2. 2. The electric machine (100) according to the preceding claim, wherein the frame element (128) is made of a plastic material.
  3. 3. The electric machine (100) of any one of the preceding claims, wherein the frame element (128) is adapted to simultaneously press against the plurality of power transistors (126) arranged in an array with respect to the bottom wall (123).
  4. 4. The electric machine (100) of any one of the preceding claims, wherein the frame element (128) further comprises at least one pair of oppositely disposed retaining portions (128 a) extending therefrom towards the bottom wall (123), the retaining portions being adapted to retain the respective power transistor (126) and prevent relative axial movement of the power transistor (126) relative to the frame element (128).
  5. 5. The electric machine (100) according to any one of the preceding claims, wherein the frame element (128) further comprises a positioning pin (128 b), the positioning pin (128 b) being received in a hole (126 b) formed on the respective power transistor (126) and being adapted to position the power transistor (126) with respect to the bottom wall (123) and to prevent a relative lateral movement of the power transistor (126) with respect to the frame element (128).
  6. 6. The electric machine (100) of any of the preceding claims, wherein the frame element (128) further comprises guide holes (128 c), the guide holes (128 c) being for receiving lead frames (126 c) emanating from corresponding power transistors (126) and extending towards the printed circuit board (124) for guiding the lead frames (126 c) to respective apertures (124 a) formed on the printed circuit board (124).
  7. 7. The electric machine (100) according to any one of the preceding claims, wherein the abutment (128 d) is aligned with respect to the corresponding power transistor (126) and adapted to press the power transistor (126) against the bottom wall (123) when the frame element (128) is fixed to the bottom wall (123).
  8. 8. The electric machine (100) according to any one of the preceding claims, wherein the abutment (128 d) is adapted to apply an abutment force in the range of 46N to 70N.
  9. 9. The electric machine (100) of the preceding claim, wherein the abutment (128 d) is an elongated finger with a free end overhanging from at least a portion of the perimeter of an aperture (128 d.1) formed on the frame element (128).
  10. 10. The electric machine (100) of the preceding claim, wherein the elongated finger having a free end comprises a substantially flat portion.
  11. 11. The electric machine (100) according to the preceding claim, wherein the elongated finger with free end is curved along the plane of the frame element (128) towards the bottom wall (123).
  12. 12. The electric machine (100) of any of the preceding claims, further comprising a thermal pad (150) disposed between the power transistor (126) and the bottom wall (123).
  13. 13. The electric machine (100) of any of the preceding claims, wherein the frame element (128) further comprises a metal bushing (128 e), the metal bushing (128 e) being overmolded with respect to the frame element (128) and adapted to receive a bolt (140) for mounting the frame element (128) to the bottom wall (123).

Description

Electric machine Technical Field The present invention relates to an electric machine. More particularly, the present invention relates to an assembly of power transistors of an inverter of an electric machine. Background Generally, an electric machine (e.g., an electric compressor) includes a compressor unit, an electric motor, and an inverter. The motor drives the compressor unit. The inverter regulates and provides power to the motor. The inverter is housed and held within an inverter housing. The inverter includes a printed circuit board and various heat generating electronic components such as power transistors (e.g., IGBTs/MOSFETs). Typically, power is supplied from an external power source to the printed circuit board via an electrical connector mounted on the inverter housing wall. The electrical connector is electrically coupled to the printed circuit board. A three-phase bridge circuit consisting of six power transistors converts High Voltage (HV) Direct Current (DC) to three-phase Alternating Current (AC) that drives a motor. The power transistor may generate heat during its operation. The heat generated by the power transistor during operation may cause damage to the power transistor due to fusing of key components of the power transistor or may cause breakage or failure of the power transistor due to a decrease in mechanical strength of the key components at high temperatures. Heat dissipation from the power transistor is required to prevent cracking or failure of the power transistor and to ensure effective performance of the power transistor. The power transistor is pressed against the bottom wall of the inverter case so as to radiate heat from the power transistor. The other side of the bottom wall is in contact with the refrigerant accommodated in the motor accommodation space of the motor housing, thereby functioning as a heat sink for dissipating heat from the power transistor. In order to properly dissipate heat from the power transistor, it is necessary to position the power transistor adjacent to and in sufficient contact with the bottom wall. Traditionally, metal leaf spring elements are used to press the power transistor against the bottom wall. Typically, two or more leaf springs are used to press six power transistors against the bottom wall. Each leaf spring is secured to the bottom wall by a screw so as to press a respective power transistor disposed between the leaf spring and the bottom wall against the bottom wall. However, this arrangement for pressing the power transistor against the bottom wall requires at least two metal leaf springs to be fixed to the bottom wall. Thus, mounting the leaf spring during assembly is inconvenient and time consuming. Furthermore, this arrangement of the leaf springs does not firmly hold the power transistor, and the power transistor may shift due to the power transistor sliding out of the grip of the leaf springs. Accordingly, there is a need for an improved arrangement of power transistors arranged within the front end of an inverter that may achieve proper heat dissipation. More specifically, there is a need for an improved arrangement for simultaneously pressing a plurality of power transistors against the bottom wall of an inverter housing to dissipate heat from the power transistors. Disclosure of Invention The present invention discloses an electric machine, in particular an electrically driven compressor for a motor vehicle. The electrically driven compressor includes a compressor unit, an electric motor, and an inverter. An electric motor is received in the motor housing and is adapted to drive the compressor unit. The inverter is held in the inverter housing and is adapted to process and regulate power supplied to the motor from an external power source. The inverter also includes a printed circuit board and a plurality of power transistors (also known as semiconductors or IGBTs or MOSFETs) for converting High Voltage (HV) Direct Current (DC) to three-phase Alternating Current (AC) that drives the motor. In addition, the inverter includes a frame member that is fixed to a front end cover (serving as a heat sink) of the inverter case between the printed circuit board and the bottom wall. The frame element is formed with a plurality of abutments integral therewith and adapted to abut the power transistor with respect to the bottom wall. Preferably, the frame element is made of a plastic material. According to an embodiment of the invention, the frame element is adapted to simultaneously press a plurality of power transistors arranged in an array against the bottom wall with respect to the bottom wall. In one embodiment, the frame element comprises a plurality of retaining portions, wherein at least one pair of retaining portions are oppositely disposed and extend from the frame element towards the bottom wall. The holding portion is adapted to hold the respective power transistor and to limit a relative axial movement of the power trans