WO2023017828A1

WO2023017828A1 - An electric machine

Info

Publication number: WO2023017828A1
Application number: PCT/JP2022/030486
Authority: WO
Inventors: Ribot Herve; Palanchon LAURENT; Carneiro FLORIAN; Banumurthy Hariharan; Varillon Mathieu; Ganesan Prakash; Mathesan PRAVEEN
Original assignee: Valeo Japan Co., Ltd.
Priority date: 2021-08-13
Filing date: 2022-08-09
Publication date: 2023-02-16
Also published as: CN117795833A

Abstract

The invention herein provides an electric machine for a vehicle's air-conditioner. The electric machine having a first housing to accommodate an electric motor, a second housing to accommodate an inverter unit, a first connector having a first terminal pin and a second connector having a second terminal pin. Both connectors are formed on an outer surface of the second housing and both terminal pins are adapted to pass through a wall of the second housing towards the inverter unit. The electric machine includes a first electrical connection is formed between the first terminal pin and the inverter unit inside the second housing and a second electrical connection is formed between the second terminal pin and the inverter unit inside the second housing. Further, the electric machine includes at least one partition wall formed between the first electrical connection and the second electrical connection inside the second housing.

Description

AN ELECTRIC MACHINE

The present invention generally relates to an electric machine, more particularly to an electrical compressor having an integrated inverter unit assembled in an inverter housing capable of avoiding leakage of electromagnetic noise into the inverter unit.

Generally, an electric machine, particularly electric compressor, is provided in AC loop of a vehicle. The electric compressor includes a compression unit for compressing refrigerant, an electric motor that drives the compression unit, and an inverter assembly that drives the electric motor in a controlled manner. Further, housings are provided to encapsulate respective parts of the electric compressor and are mechanically coupled together with various fasteners. In one example, a motor housing is provided to encapsulate the electric motor, and an inventor housing is provided to encapsulate the inverter unit. The electric motor provided in the compressor enables the compression unit to draw the refrigerant from an inlet port formed on the motor housing to cool the electric motor by circulating the refrigerant through the motor housing. Generally, the motor housing is formed with the aluminium material in a cylindrical shape having openings on either sides. Further, the refrigerant enters into the compression unit for compression, and flows out from the electric compressor through a discharge port formed on a rear cover that is coupled to one end of the motor housing. From other end of the motor housing, the electric motor is inserted and is coupled with the inverter housing.

Further, the inverter unit is configured to control the motor and the inverter housing further includes a High Voltage (HV) connector and a Low Voltage (LV) connector. The HV and LV connectors have a HV terminal pin and LV terminal pin. The terminal pins of the HV and LV connector are sufficiently long so that the end of the terminal pin may reach or may in contact with a printed circuit board of the inverter unit provided within the inverter housing. The HV terminal pin may provide power supply to the electric motor provided in the motor housing through the inverter unit and the LV terminal pin may provide control signals to the inverter unit. Generally, electromagnetic noise is generated from active parts of the electric motor in the motor housing. In an example, the electromagnetic noise (EMC noise) may be generated around the HV terminal pin due to the high voltage experienced by the HV pin. Further, there is a possibility of interaction of the electromagnetic noise between the LV and HV terminal pins and such noise may affect the HV signal while entering into the filter components of the inverter unit. As a result, it causes an adverse effect on the control signals of the inverter unit, thereby resulting in improper functioning of the inverter unit.

Accordingly, there remains a need for an electric machine provided with features that avoid interaction of electromagnetic noise between a high voltage terminal pin and a low voltage terminal pin of the electric machine. Further, there remains another need for a protection formed between a high voltage terminal pin and a low voltage terminal pin inside an inverter housing of an electric machine to avoid interaction of electromagnetic noise between two pins. Further, there remains another need for an electric machine provided with features that protect an inverter unit from interference of the electromagnetic noise.

In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention.

In view of the foregoing, an embodiment of the invention herein provides an electric machine, particularly an electric compressor for a vehicle’s air-conditioner. The electric machine includes a first housing adapted to accommodate an electric motor, and a second housing adapted to accommodate an inverter unit. Here, the inverter unit is configured to control the electric motor. Further, the electric machine includes a first connector having a first terminal pin and a second connector having a second terminal pin. The first connector is formed on an outer surface of the second housing and the second connector is formed in the vicinity of the first connector on the outer surface of the second housing. Further, the first terminal pin and the second terminal pin are adapted to pass through a base wall of the second housing towards the inverter unit. The electric machine further includes a first electric connection and the second electric connection formed inside the second housing. The first electrical connection is formed between the first terminal pin and the inverter unit inside the second housing and the second electrical connection is formed between the second terminal pin and the inverter unit inside the second housing. Further, the electric machine includes at least one partition wall formed between the first electrical connection and the second electrical connection inside the second housing.

In one embodiment, the partition wall is integrally formed on an inner surface of the base wall of the second housing.

In another example of the above embodiment, the partition wall is coupled to an inner surface of the base wall of the second housing.

In another embodiment, the partition wall is coupled to a printed circuit board of the inverter unit.

In one example, at least one of the first electrical connection and the second electrical connection is an electrical conductor connected between respective terminal pin and the printed circuit board of the inverter unit.

In another example, at least one of the first electrical connection and the second electrical connection is a bus-bar connected between respective terminal pins and the printed circuit board of the inverter unit.

In yet another example, at least one of the first electrical connection and the second electrical connection is a pin extending from one end of the respective first and second terminal pins to the printed circuit board of the inverter unit.

Further, the partition wall is an aluminum wall.

Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein:
Fig.1 is illustrates a block diagram of an electric machine, in accordance with an embodiment of the present invention; Fig.2 is illustrates a schematic view of a second housing of the electric machine showing the connectors of Fig. 1; Fig.3A is illustrates a sectional view of the second housing of Fig. 2 at the plane L-L’; Fig.3B is illustrates an enlarged view of the sectional view of the second housing of Fig. 3A depicting a partition and a printed circuit board. Fig.4A is illustrates an exploded view of the second housing of Fig. 1 depicting an inverter unit, electrical connections and the partition wall; Fig.4B is a schematic view of the second housing of Fig. 1 depicting position of the partition wall; Fig.5A is illustrates another sectional view of the second housing of Fig. 2 at the plane L-L’, in accordance with another embodiment of the present invention; and Fig.5B is illustrates another sectional view of the second housing of Fig. 2 at the plane L-L’ in accordance with another embodiment of the present invention.

It must be noted that the figures disclose the invention in a detailed enough way to be implemented, the figures helping to better define the invention if needs be. The invention should however not be limited to the embodiments disclosed in the description.

The present invention relates to an electric machine, particularly to an electric compressor, provided in an air-conditioning loop of a vehicle. Generally, the electric compressor includes a motor housing provided with an electric motor and an inverter housing provided with an inverter unit. The motor housing and the inverter housing are coupled together to enable connection between the electric motor and the inverter unit. Further, the electric motor is connected with a compression unit to compress a refrigerant flowing therein. To enable fluid tight connection between the motor housing and the inverter housing, a rubber coated metallic gasket is provided in between the motor housing and the inverter housing. Further, the inverter housing is provided with a high voltage (HV) connector having high voltage terminal pins and a low voltage (LV) connector having low voltage terminal pins. In some example, the HV connector and LV connector are in proximity to each other. As the electromagnetic noise generated around the HV terminal pin, there is possibility of interaction of the electromagnetic noise between the LV and HV terminal pins and such noise may affect the HV signal while entering into the filter components of the inverter unit. As a result, it causes an adverse effect on the control signals of the inverter unit, thereby resulting in improper functioning of the inverter unit. To avoid such a scenario, a partition wall is provided between the HV pin and LV pin. The partition wall, in turns, connected to the vehicle’s ground so as to compensate the electromagnetic noise generated in the inverter housing. Further, placement and function of the partition wall are explained with respect to the following figures.

Fig. 1 illustrates a block diagram of an electric machine 100, in accordance with an embodiment of the present invention. In present embodiment, the electric machine 100 is an electric compressor, particularly, an inverter integrated motor driven electric compressor 100. The electric machine 100 is provided in a refrigerant circuit of a vehicle. Generally, the electric machine 100 is provided in the refrigerant circuit of the vehicle to compress the refrigerant flowing therein. The electric machine 100 includes a first housing 102 adapted to accommodate an electric motor 104, a second housing 202 adapted to accommodate an inverter unit 204, and a third housing 120 adapted to accommodate a compression unit 122. Further, the first housing 102, the second housing 202 and the third housing 120 are integrally fastened with fastening means (not shown), such as bolts, so as to form a casing of the electric machine 100. In one example, the first housing 102, the second housing 202 and the third housing 120 are formed of metal, particularly of aluminium die-casting.

The electric motor 104 provided in the first housing 102 includes a stator and a rotor (not shown in Fig. 1). Further, a rotary shaft 106 is connected to the rotor, and the rotary shaft 106 is extending into the third housing 120 to couple with the compression unit 122. The first housing 102 being motor housing is formed of a cylindrical shape having openings on both sides to accommodate the electric motor 104. Further, one end of the first housing 102 is coupled to the third housing 120 having the compression unit 122. From other end of the first housing 102, the electric motor 104 is inserted and is coupled with the second housing 202 having the inverter unit 204. When the electric motor 104 is energized, the rotary shaft 106 drives the compression unit 122 provided in the third housing 120.

The compression unit 120 provided in the third housing 122 includes a fixed scroll and an orbiting scroll for compressing the refrigerant flowing therein. In one example, the fixed scroll is fixedly and integrally formed with the third housing 120. The orbiting scroll is rotatably connected with an eccentric pin formed of the rotary shaft 106 extending from the first housing 102. The orbiting scroll is adapted to compress the refrigerant at a compression space defined between the fixed scroll and the orbiting scroll when the rotary shaft 106 is rotated by the electric motor 104. In other words, the refrigerant in the compression space is compressed by orbiting motion of the orbiting scroll with respect to the fixed scroll. Further, a suction port 124 is formed integrally with the first housing 102 for sucking the refrigerant into the electric machine 100. The suctioned refrigerant from the suction port 124 at the first housing 102 may flow through the electric motor 104 to cool or absorb heat generated by the electric motor 104 and enter into the third housing 120 for compression process. Thereafter, the compressed refrigerant egresses from the electric machine 100 through a discharge port 126 formed integrally with the third housing 120.

The inverter unit 204 accommodated in the second housing 202, being an inverter housing, is adapted to drive the electric motor 104 in a controlled manner. In one example, the inverter unit 204 can also referred to as inverter assembly. The inverter unit 204 includes a plurality of electronic components mounted on a printed circuit board to perform required operations. The circuit board is powered from an external source, such as a battery of the vehicle. The second housing 202 has an outer surface 210A and an inner surface 210B and provided with

connectors

206, 208 on the outer surface 210A of the second housing 202. Further, geometry and position of the

connectors

206, 208 are described with the forthcoming figures.

Further, a hermetic terminal 128 is provided on an end wall or outer surface 210A of the second housing 202 and is adapted to couple with the electric motor 104. The inverter unit 204 generates controlled inputs for the electric motor 104 and transmits such inputs to the electric motor 104 through the hermetic terminal 128. Further, the inputs generated by the inverter unit 204 may control the speed of the electric motor 104, thereby controlling the compression unit 122.

Fig. 2 illustrates a schematic view of the second housing 202 showing the

connectors

206, 208 of Fig. 1. In this example, the

connectors

206, 208 are a first connector 206 and a second connector 208. The first connector 206 can be a high voltage connector and the second connector can be a low voltage connector. Particularly, the first connector 206 and the second connector 208 are formed on the outer surface 210A of the second housing 202 and in vicinity to each other. Further, the second housing 202 may include a base wall 210 having the outer surface 210A and the inner surface 210B. Here, the inner surface 210B of the base wall 210 means the surface facing towards the inverter unit 204 and the outer surface 210A of the base wall 210 means the surface facing away from the inverter unit 204. Further, the base wall 210 is clearly shown in the forthcoming figures. The base wall 210 may be provided with sidewalls 210C formed on the periphery of the base wall 210 to define a space to receive the inverter unit 204 in the second housing 202.

As explained above, the first connector 206 and the second connector 208 are formed on the outer surface 210A of the base wall 210 of the second housing 202. In other words, the first connector 206 and the second connector 208 are protruded from the base wall 210 facing towards the first housing 102 as shown in Fig. 1. Although the first connector 206 and the second connection 208 are formed on the outer surface 210A facing the first housing 102, it is possible to define the first connector 206 on the outer surface 210A facing towards the first housing 102, and the second connector 208 on a wall 210D facing away from the first housing 102. Here, the wall refers a cover for closing the second housing 202 upon assembling of the inverter unit 204. Further, the first connector 206 includes at least one first terminal pin 206A adapted to be electrically connected to the inverter unit 204, and the second connector 208 includes at least one second terminal pin 208A adapted to be electrically connected to the inverter unit 204.

Figs. 3A and 3B illustrate sectional views of the second housing 202 of Fig. 2 at the plane L-L’. The sectional view of the second housing 202 shown in Fig. 3A depicts the inverter unit 204 and the connection between the inverter unit 204 and the first terminal pin 206A and the second terminal pin 208A. As explained above, the sidewalls 210C formed on the periphery of the base wall 210 of the second housing 202 to define the space 212 to receive the inverter unit 204. The first terminal pin 206A and the second terminal pin 208A may pass through the base wall 210 of the second housing 202 towards the inverter unit 204. In other words, the first terminal pin 206A and the second terminal pin 208A may reach the space 212 defined inside the second housing 202. In one example, the first terminal pin 206A and the second terminal pin 208A are long enough to pass through the base wall 210 of the second housing 202 and reach the space 212 defined by the base wall 210 and the sidewalls 210C.

The electric machine 100 further includes electrical connections established between the connectors and the inverter unit 204. Particularly, the electrical connections can be a first electrical connection 302 and a second electrical connection 304. The first electrical connection 302 is formed between the first terminal pin 206A of the first connector 206 and the inverter unit 204 inside the second housing 202, so that the high voltage can be supplied to the inverter unit 204 through the first terminal pin 206A. Similarly, the second electrical connection 304 is formed between the second terminal pin 208A of the second connector 208 and the inverter unit 204 inside the second housing 202, so that the low voltage signal can be received at the inverter unit 204. As shown in Figs. 3A-B, the first electrical connection 302 and the second electrical connection 304 are formed inside the second housing 202. As the first connector 206 are the second connector 208 are formed in the vicinity to each other, the first electrical connection 302 is in in the vicinity of the second electrical connection 304.

As explained above, the electromagnetic noise is generated around the first terminal pin 206A or the first electrical connection 302, which is the high voltage terminal. As the first electrical connection 302 is in in the vicinity of the second electrical connection 304, such electromagnetic noise may interact with the second electrical connection 302, that may determinately affect the functions of the inverter unit 204. To avoid such problems, at least one partition wall 306 formed between the first electrical connection 302 and the second electrical connection 304 inside the second housing 202. The partition wall 306 may be connected to the vehicle’s ground, so that the electromagnetic noise can be ground without affecting functions of the inverter unit 204. In one example, the partition wall 306 is made of aluminium or any other conductive materials. In this example, the partition wall 306 is extended between the inner surface 210B of the base wall 210 and the printed circuit board 214 of the inverter unit 204, as shown in Fig. 3B.

As shown in Fig. 3B, the partition wall 306 extend from the inner surface 210B of the base wall 210 of the second housing 202. In this embodiment, the partition wall 306 is integrally formed with the inner surface 210B of the base wall 210 of the second housing 202, so as to extend towards the printed circuit board 214 of the inverter unit 204.. The height of the partition wall 306 is less than the distance between the inner surface 210B of the base wall 210 and the printed circuit board 214. Preferably, a gap G between the tip of the partition wall 306 and the printed circuit board 214 is designed to be small but greater than zero considering the Insulation criteria of the electric machine 100 and stack up tolerance of the related parts. In this example, the gap G is approximately 1 mm. As the partition wall 306 is provided in between the first electrical connection 302 and the second electrical connection 304, the electromagnetic noise generated around the first electrical connection 302 does not reach the second electrical connection 304, rather it is grounded through the partition wall 306, thereby control functions of the inverter unit 204 is unaffected.

Figs. 4A and 4B illustrates different views of the second housing 202 of Fig. 1. In this example, Fig. 4A is an exploded view of the second housing 202 depicting the inverter unit 204, the

electrical connections

302, 304 and the partition wall 306. Fig. 4B is a schematic view of the second housing 202 of Fig. 1 depicting position of the partition wall 306. As shown in Fig. 4A, the partition wall 306 is formed between the first electrical connection 302 and the second electrical connection 306, so as to isolate the first electrical connection 302 from the second electrical connection 304. In one example, the partition wall 306 along with the sidewalls 210C and other design provided on the base wall 210 are configured to form a chamber structure so that the second electrical connection 304 is free from the electromagnetic noise present around the first electrical connection 302.

In the preferred example, at least one of the first electrical connection 302 and the second electrical connection 304 is cable connected between respective

terminal pins

206A, 208A and the printed circuit board 214 of the inverter unit 204. It is possible that the both first electrical connection 302 and the second electrical connection 304 are electrical conductors. As shown in Figs. 3A-B, the first electrical connection 302 is a cable connected between the first terminal pin 206A and the inverter unit 204 and the second electrical connection 304 is a pin extended between the second terminal pin 208A and the inverter unit 204.

In another example, at least one of the first electrical connection 302 and the second electrical connection 304 is a bus-bar connected between respective

terminal pins

206A, 208A and the printed circuit board 214 of the inverter unit 204. It is possible that the both first electrical connection 302 and the second electrical connection 304 are bus-bars.

In yet another example, at least one of the first electrical connection 302 and the second electrical connection 304 is a pin conductor extending from one end of the respective terminal pins 206A, 208A to the printed circuit board 214 of the inverter unit 204. It is possible that the both first electrical connection 302 and the second electrical connection 304 are pins. In case the

electrical connections

302, 304 are pins, it is possible to integrally form the

electrical connections

302, 304 with the first terminal pin 206A and the second terminal pin 208A. In such case, the first electrical connection 302 may be integrally formed with the first terminal pin 206A and the second electrical connection 304 may be integrally formed with the second terminal pin 208A.

Fig. 5A illustrates another sectional view of the second housing 202 of Fig. 2 at the plane L-L’, in accordance with another embodiment of the present invention. In the present embodiment, the partition wall 306 is an independent element provided between the first electrical connection 302 and the second electrical connection 304. Here, the partition wall 306 is coupled to the inner surface 210B of the base wall 210 of the second housing 202. The partition wall 306 may be coupled to the base wall 210 of the second housing 202 by screws or any other connecting means such as rivet.

Fig. 5B illustrates another sectional view of the second housing 202 of Fig. 2 at the plane L-L’, in accordance with another embodiment of the present invention. In the present embodiment, the partition wall 306 is an independent element provided between the first electrical connection 302 and the second electrical connection 304. Here, the partition wall 306 is coupled to the printed circuit board 214 of the inverter unit 204 provided in the second housing 202. The partition wall 306 may be coupled to the printed circuit board 214 by screws or any other connecting means such as rivet.

As explained above, the partition wall 306 may act as barrier or conductor to ground the electromagnetic noise generated around the high voltage terminal 206A and the first electrical connection 302. Hence, such noise may not affect the control signals flowing through the second electrical connection 304, thereby functions of the inverter unit 204 is unaffected. As a result, malfunction of the electrical machine 100 can be avoided.

All the above-described embodiments are just to explain the present invention while more embodiments and combinations thereof might exist. Hence, the present invention should not be limited to the above-described embodiments alone.

Claims

An electric machine (100), comprising:
a first housing (102) adapted to accommodate an electric motor (104);
a second housing (202) adapted to accommodate an inverter unit (204), wherein the inverter unit (204) is configured to control the electric motor (104);
a first connector (206) having a first terminal pin (206A) formed on an outer surface (210A) of the second housing (202);
a second connector (208) having a second terminal pin (208A) formed in the vicinity of the first connector (206) on the outer surface (210A) of the second housing (202), wherein the first terminal pin (206A) and the second terminal pin (208A) are adapted to pass through a base wall (210) of the second housing (202) towards the inverter unit (204), characterized in that,
a first electrical connection (302) formed between the first terminal pin (206A) and the inverter unit (204) inside the second housing (202);
a second electrical connection (304) formed between the second terminal pin (208A) and the inverter unit (204) inside the second housing (202); and
at least one partition wall (306) formed between the first electrical connection (302) and the second electrical connection (304) inside the second housing (202).
The electric machine (100) as claimed in claim 1, wherein the partition wall (306) is integrally formed on an inner surface (210B) of the base wall (210) of the second housing (202).
The electric machine (100) as claimed in claim 1, wherein the partition wall (306) is coupled to an inner surface (210B) of the base wall (210) of the second housing (202).
The electric machine (100) as claimed in claim 1, wherein the partition wall (306) is coupled to a printed circuit board of the inverter unit (204).
The electric machine (100) as claimed in the claims 1 to 4, wherein at least one of the first electrical connection (302) and the second electrical connection (304) is an electrical conductor connected between respective terminal pin and the printed circuit board of the inverter unit (204).
The electric machine (100) as claimed in the claims 1 to 4, wherein at least one of the first electrical connection (302) and the second electrical connection (304) is a bus-bar connected between respective terminal pins (206A, 208A) and the printed circuit board (214) of the inverter unit (204).
The electric machine (100) as claimed in the claims 1 to 4, wherein at least one of the first electrical connection (302) and the second electrical connection (304) is a pin extending from one end of the respective first and second terminal pins (206A, 208A) to the printed circuit board (214) of the inverter unit (204).
The electric machine (100) as claimed in any of the preceding claims, wherein the partition wall (306) is an aluminum wall.