CN107364456B

CN107364456B - Inverter driving assembly and bus bar for inverter driving assembly of vehicle

Info

Publication number: CN107364456B
Application number: CN201611168887.0A
Authority: CN
Inventors: M.A.墨菲; J.J.沃尔夫; J.D.库滕库勒
Original assignee: GE Global Sourcing LLC
Current assignee: Transportation IP Holdings LLC
Priority date: 2016-05-12
Filing date: 2016-12-16
Publication date: 2020-10-27
Anticipated expiration: 2036-12-16
Also published as: CN112172843B; CN112172843A; CN107364456A

Abstract

The invention relates to an inverter driving system, a bus bar and an assembly. Concretely, an inverter drive assembly includes a first bus bar (100) having a plurality of bushings, including at least a first bushing (114) and a second bushing (116), the first bus bar (100) configured to receive at least one DC link capacitor of the inverter drive assembly via the second bushing (116); a second bus bar (120) electrically connected to the first bus bar (100) at the first bushing (114); and an inverter electrically connected to the second bus bar, the inverter configured to receive current via the second bus bar, wherein a height of the first sleeve (114) defines an air gap (126) of approximately 5 millimeters between the first bus bar and the second bus bar.

Description

Inverter driving assembly and bus bar for inverter driving assembly of vehicle

Technical Field

Embodiments of the invention generally relate to inverter drive assemblies. Other embodiments relate to a bus bar for an inverter drive assembly of an electric vehicle.

Background

Traction vehicles, such as locomotives and other off-highway vehicles ("OHVs"), for example, may employ electric traction motors to drive the wheels of the vehicle. In some of these vehicles, the motor is an Alternating Current (AC) motor whose speed and power are controlled by varying the frequency and current of the AC electrical power supplied to the motor. Typically, electrical power is supplied as direct current power at some point in the vehicle system and thereafter is tied back to AC power of controlled frequency and amplitude. The electrical power may originate from an on-board ac motor driven by an internal combustion engine or may be obtained from a wayside power source such as a third rail or overhead catenary.

In conventional systems, power is reversed in a solid state inverter incorporating multiple diodes and electronic switching devices. In locomotive, other large OHV, or transportation applications, the traction motors may produce over 1000 horsepower per motor, requiring very high power handling capability through the associated inverter. This in turn requires the use of semiconductor switching devices, such as GTOs (gate turn off silicon controlled rectifiers) or IGBTs, which are capable of controlling such high powers and of dissipating a large amount of heat generated in the semiconductor devices due to internal loss generating characteristics.

Semiconductor devices are typically mounted on a heat transfer device, such as a heat sink, which helps transfer heat away from the semiconductor device and thus prevents thermal failure of the device. The circuit (or electrical line) area in which the semiconductor device is located may include various control and timing lines (including low power semiconductors) for controlling the switching of the power semiconductors.

In OHVs, inverter drive systems for large AC motor applications typically include an inverter associated with each traction motor. Conventional designs for power inverters may include a layered bus bar array that interconnects semiconductor device (e.g., IGBT) modules and several DC link capacitors. In particular, the plurality of DC link capacitors are typically connected to the inverter via an arrangement of bus bars, which includes a horizontal capacitor bus bar that receives the plurality of DC link capacitors and is coupled to a vertical interconnecting bus bar. The vertical interconnect bus bar is coupled at a distal end to the IGBT modules of the inverter.

Known bus bar designs for high power applications, while generally applicable to what is considered conventional performance, may benefit from improved designs. In particular, certain existing designs may be prone to corona discharge in the region where the vertical bus bars of the inverter are coupled to the horizontal bus bars, which may lead to insulation degradation and ultimately to short circuits.

Disclosure of Invention

In one embodiment, an inverter drive assembly includes a first bus bar, a second bus bar, and an inverter. The first bus bar has a plurality of bushings, including at least a first bushing and a second bushing, and is configured to receive at least one DC link capacitor of the inverter drive assembly via the second bushing. The second bus bar is electrically connected to the first bus bar at the first bushing. The inverter is electrically connected to the second bus bar and configured to receive current via the second bus bar. The height of the first sleeve defines an air gap of approximately 5 millimeters between the first bus bar and the second bus bar.

In one embodiment, a bus bar for an inverter drive assembly of a vehicle includes a first layer; a second layer laminated to the first layer; at least one first bushing configured to receive a capacitor; and at least one second bushing configured to receive an inverter bus bar on an inverter connected to the inverter drive assembly. The at least one second sleeve is about 5 millimeters high. Furthermore, the first and second layers overlap substantially completely.

In one embodiment, a method (e.g., for an inverter drive assembly) includes the steps of: providing a first bus bar, and connecting a second bus bar having a conductor to the first bus bar to define an air gap between the first bus bar and the second bus bar. The air gap is substantially 5 mm.

In one aspect, the present invention provides the following technical solutions.

Technical solution 1. an inverter driving assembly includes:

a first bus bar having a plurality of bushings including at least a first bushing and a second bushing, the first bus bar configured to receive at least one DC link capacitor of the inverter drive assembly via the second bushing;

a second bus bar electrically connected to the first bus bar at the first bushing; and

an inverter electrically connected to the second bus bar, the inverter configured to receive current via the second bus bar;

wherein a height of the first bushing defines an air gap of approximately 5 millimeters between the first bus bar and the second bus bar.

Technical solution 2 the inverter driving assembly according to technical solution 1, characterized in that:

the height of the first sleeve is about 5 mm.

Technical means 3. the inverter driving module according to technical means 2, characterized in that:

the height of the second sleeve is about 1.8 millimeters.

Technical means 4. the inverter driving module according to technical means 2, characterized in that:

the second bus bar includes a conductor secured to the first sleeve of the first bus bar; and

the air gap is defined by a lower surface of the conductor and an upper surface of the first bus bar.

Technical means 5 the inverter driving module according to the technical means 4, characterized in that:

the first and second bus bars are oriented substantially perpendicular to each other.

Technical means 6. the inverter driving module according to the technical means 4, characterized in that:

the inverter drive assembly is mounted on an off-highway vehicle.

Technical means 7. the inverter driving module according to the technical means 4, characterized in that: the at least one first sleeve is a pair of first sleeves.

Technical means 8 the inverter driving module according to the technical means 4, characterized in that: the first bus bar is a laminated bus bar having a first layer and a second layer;

wherein the first layer and the second layer overlap substantially completely.

Technical solution 9 a bus bar for an inverter driving assembly of a vehicle, comprising:

a first layer;

a second layer laminated to the first layer;

at least one first bushing configured to receive a capacitor; and

at least one second bushing configured to receive an inverter bus bar connected to an inverter of the inverter drive assembly;

wherein the at least one second sleeve is about 5 millimeters high; and

wherein the first layer and the second layer overlap substantially completely.

The bus bar according to claim 9, wherein:

the height of the second bushing defines an air gap between the first layer and a conductor of the inverter bus bar.

The bus bar according to claim 11, wherein:

the air gap is about 5mm high.

The bus bar according to claim 12, wherein:

the at least one first sleeve is about 1.8 millimeters high.

The bus bar according to claim 13, wherein:

the bus bar is installed in the vehicle, and the vehicle is an off-highway vehicle.

The bus bar according to claim 14 or 13, wherein:

the off-highway vehicle is a locomotive.

The bus bar according to claim 15, wherein:

the at least one second bushing is configured to receive the inverter bus bar in a substantially perpendicular orientation relative to the bus bar.

The method of claim 16, comprising:

providing a first bus bar; and

connecting a second bus bar having a conductor to the first bus bar to define an air gap between the first bus bar and the second bus bar;

wherein the air gap is substantially 5 mm.

The method according to claim 17, to claim 16, characterized in that:

the first bus bar comprises a first sleeve having a height of substantially 5 millimeters; and

the second bus bar includes a conductor electrically connected to the first sleeve;

wherein the air gap is a space between the first bus bar and the conductor.

The method according to claim 16, characterized in that the method further comprises:

connecting the second bus bar to an inverter; and

connecting the first bus bar to a capacitor.

The method according to claim 19, to claim 16, wherein:

the first bus bar includes a second sleeve having a height of about 1.8 millimeters.

On the other hand, the invention also provides the following technical scheme.

Technical solution 1. an inverter driving assembly includes:

the height of the first sleeve is about 5 mm.

the height of the second sleeve is about 1.8 millimeters.

the inverter drive assembly is mounted on an off-highway vehicle.

Technical means 7. the inverter driving module according to the technical means 4, characterized in that:

the at least one first sleeve is a pair of first sleeves.

Technical means 8 the inverter driving module according to the technical means 4, characterized in that:

the first bus bar is a laminated bus bar having a first layer and a second layer;

wherein the first layer and the second layer overlap substantially completely.

a first layer;

a second layer laminated to the first layer;

at least one first bushing configured to receive a capacitor; and

wherein the at least one second sleeve is about 5 millimeters high; and

wherein the first layer and the second layer overlap substantially completely.

The bus bar according to claim 9, wherein:

The bus bar according to claim 11, wherein:

the air gap is about 5mm high.

The bus bar according to claim 12, wherein:

the at least one first sleeve is about 1.8 millimeters high.

The bus bar according to claim 13, wherein:

the vehicle is an off-highway vehicle.

The bus bar according to claim 14, wherein:

the vehicle is a locomotive.

The bus bar according to claim 15, wherein:

the inverter bus bar is oriented substantially perpendicular to the bus bar.

Drawings

The invention will be better understood from the following description of non-limiting examples, read with reference to the attached drawings, in which:

FIG. 1 is a simplified, partial schematic illustration of a locomotive.

Fig. 2 is a simplified schematic diagram of a power circuit for a vehicle.

Fig. 3 is a bottom perspective view of a bus bar according to one embodiment of the present invention.

Fig. 4 is a top perspective view of the bus bar of fig. 3.

Fig. 5 is a bottom plan view of the bus bar of fig. 3.

Fig. 6 is a top plan view of the bus bar of fig. 3.

Fig. 7 is a right side elevational view of the bus bar of fig. 3.

Fig. 8 is a front elevational view of the bus bar of fig. 3.

Fig. 9 is a left side perspective view of the bus bar of fig. 3, shown with a vertical bus bar coupled thereto.

Fig. 10 is a right side perspective view of the bus bar of fig. 3, shown with a vertical bus bar coupled thereto.

Fig. 11 is a left side elevational view of the bus bar of fig. 3, shown with a vertical bus bar coupled thereto.

Fig. 12 is a top plan view of the bus bar of fig. 3, shown with a vertical bus bar coupled thereto.

Fig. 13 is a rear elevational view of the bus bar of fig. 3, shown with a vertical bus bar coupled thereto.

Fig. 14 is a detailed view showing an air gap between the bus bar of fig. 3 and a vertical bus bar coupled thereto.

Detailed Description

Reference will now be made in detail to the exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts without the necessity of a repeated description. Although exemplary embodiments of the present invention are described with respect to an inverter drive assembly for a locomotive or OHV, embodiments of the present invention may also be adapted for use in connection with electric machines and vehicles, such as machines employing electric motors, such as AC or DC motors, in general. As used herein, "in electrical contact," "in electrical communication," and "electrically coupled" mean that the referenced elements are directly or indirectly connected such that an electrical current may flow from one element to another. The connection may include a direct conductive connection (i.e., an inductive or active element without an intervening capacitance), an inductive connection, a capacitive connection, and/or any other suitable electrical connection. Intervening members may be present.

Before turning to the present invention, reference is first made to FIG. 1, which shows a simplified partial cross-sectional view of an electric traction vehicle 10, shown as a locomotive. Although a locomotive is shown in fig. 1 and 2, the present invention is also applicable to traction systems in which power is received from an external power generation source and distributed via a catenary or third rail, and more generally to electric machines that employ electric motors.

The locomotive 10 of FIG. 1 includes a plurality of traction motors, not visible in the figures, positioned behind the drive wheels 12 and coupled in driving relationship to an axle (axle) 14. The motor is preferably an Alternating Current (AC) electric motor and the locomotive includes a plurality of electrical inverter lines for controlling electrical power to the motor.

FIG. 2 shows a simplified schematic of an electric traction system for locomotive 10, which includes an alternator 16 driven by an on-board internal combustion engine, such as a diesel engine (not shown). The power output of the alternator 16 is regulated in a well known manner by field excitation control represented by block 18. The electrical power from the alternator 16 is rectified (block 20) and coupled to the inverter 22. The inverter 22 uses high power semiconductor switching devices, such as IGBTs or GTOs, to convert the rectified power to variable frequency, variable amplitude power for application to the AC motor 24.

Referring again to fig. 1, the electrical power circuit is located at least partially within an inverter drive assembly compartment or enclosure (envelope) 26. Within the enclosure 26, the high power semiconductor devices (not shown in fig. 1) are mounted to an air-cooled heat sink. The control electronics for the inverters 22 and the field control 18, as well as other electronic components, are packaged in a conventional manner on a circuit board in a rack (rack) held within an enclosure 26. Mounted outside of the compartment 26 are one or more blowers (not shown) that provide air cooling for the electrical compartment and the heat sink.

Generally, during operation, alternating current is fed from an alternator (not shown) to the inverter drive assembly via an AC bus bar. The rectifier is configured to convert the alternating current into direct current, which is then fed up to the horizontal capacitor bus bar, and finally to the DC link capacitor connected to the horizontal bus bar. The capacitor is configured to supply direct current to an inverter module (not shown) mounted to a vertical bus bar that is itself connected to a horizontal capacitor bus bar in a manner heretofore known in the art. The direct current is then converted to AC power of controlled frequency and amplitude and supplied to the traction motors of the vehicle 10. (As used herein, "vertical" and "horizontal" refer, in one aspect, to components/elements that are perpendicular to one another. in another aspect, they refer to components that, when installed in a vehicle and the vehicle is operatively disposed on a horizontal surface path surface, are perpendicular to the surface and parallel to the surface, respectively (e.g., as defined by the long axis of the component))

Turning now to fig. 3-8, various views of a horizontal capacitor bus bar 100 are shown, according to one embodiment of the invention. As shown therein, the capacitor bus bar 100 is generally rectangular in shape and is of a laminated construction having a plurality of layers including a first layer 110 and a second layer 112. The first and second layers overlap substantially completely. As used herein, "substantially completely overlaps" means that the layers have substantially the same surface area and are aligned one on top of the other such that only narrow regions of one layer are not aligned with the other layer. In one embodiment, the misaligned region of a layer may be less than about 0-10% of the entire surface area of the layer (such that about 90-100% of the surface area of the respective layer overlaps) and more specifically less than about 0-5% of the entire surface area of the layer (such that about 95-100% of the surface area of the respective layer overlaps). In one embodiment, the layers completely overlap such that there are no portions of one layer protruding from the other layer.

The bus bar 100 includes a plurality of through holes (via) arranged in a column, including a first through hole 114 and a second through hole 116. For example, the through-

holes

114, 116 are configured as bushings for receiving threaded fasteners, such as cap screws (not shown), for electrically connecting the bus bar 100 with capacitors, other bus bars, and/or other components of the inverter drive system. As best shown in fig. 7 and 8, the first via or sleeve 114 extends to a greater extent over the first layer 110 or surface of the bus bar 100 than the second via 116. That is, the first sleeve 114 is higher than the second sleeve 116.

Referring now to fig. 9-13, in one embodiment, the first bushing 114 is configured to facilitate coupling the vertical bus bar 120 to the horizontal capacitor bus bar 100. As discussed above, the vertical bus bar 120 is connected to the inverter of the drive assembly for conveying DC electrical power from the DC link capacitor to the inverter, where it is converted to AC electrical power for use by the traction motors. As shown therein, the vertical bus bar may take the form of any bus bar generally known in the art and includes a bare conductor 122 electrically and mechanically coupled to the first sleeve 114 of the horizontal capacitor bus bar 100 by a threaded fastener 124.

As best shown in fig. 14, the height of the first sleeve 114 defines an air gap 126 between the surface of the first layer 110 of the horizontal bus bar 100 and the bare conductor 122 of the vertical bus bar 120. In one embodiment, the first sleeve 114 is approximately 5 millimeters high, defining a 5 millimeter air gap 126 between the bare conductor 122 and the bus bar 100. As used herein, "about" means plus or minus (±) 10% in one embodiment.

In one embodiment, the second sleeve 116 is approximately 1.8 millimeters high. The sleeve 114 is thus about 3.2 millimeters higher than the sleeve 116. In one embodiment, the first sleeve 114 is substantially just 5 millimeters high, thereby defining an air gap 126 that is substantially just 5 millimeters wide.

This 5mm air gap between the conductors 122 of the vertical bus bar 120 and the top layer 110 of the horizontal bus bar 100 is in contrast to the much narrower gaps of prior designs, which can typically be on the order of about 1.8 mm (due to the standard bushing height of 1.8 mm). The sleeve 114 of the bus bar 100 is thus as much as three times higher compared to the sleeve of a standard bus bar.

It has been found that such a large air gap of substantially 5 millimeters improves the reliability of the bus bar 100 by reducing the possibility of corona discharge between the bus bar 100 and the bare conductor 122, while also maintaining inductance below an undesirable level by providing substantially complete overlap between the first layer 110 and the second layer 112 of the bus bar 100. (this height cannot be increased to an arbitrary height because the inductance can be raised to the point where normal electrical functionality is compromised.) the increased overlap between the two

DC layers

110, 112 also serves to reduce inductance compared to prior designs, while also reducing the likelihood of corona discharge. In particular, existing horizontal bus bars with standard height bushings (i.e., approximately 1.8 millimeters high) may have an increased likelihood of corona discharge occurring between the bare copper conductors of the horizontal and vertical bus bars. In prior designs, this corona discharge may eventually reduce the insulation of the bus bar, potentially resulting in a short circuit. The bus bar 100 substantially eliminates this problem by providing a sleeve 114 of increased height, coupled substantially overlappingly between the two

layers

110, 112, while maintaining the desired electrical performance.

In one embodiment, the bus bar 100 has a 5mm sleeve height, thereby defining a 5mm air gap, particularly suitable for 1200 and 1500 volt nominal DC link voltages. In one embodiment, the bus bar 100 is particularly suitable for use in an OHV drive system having a nominal link voltage of 1200 and 1550 volts. During testing, it has been found that the average electric field (field) in the air gap defined by a bus bar with standard height bushings (e.g., about 1.8 millimeters) is about 800V/mm (1000V/mm for insulation with 0.5mm on the bus bar). However, the average electric field in the air gap defined by the increased bushing height of the bus bar 100 of the present invention is only 300V/mm.

In one embodiment, an inverter drive assembly is provided. The assembly includes a first bus bar having a plurality of bushings, including at least a first bushing and a second bushing, the first bus bar configured to receive at least one DC link capacitor of the inverter drive assembly via the second bushing; a second bus bar electrically connected to the first bus bar at the first bushing; and an inverter electrically connected to the second bus bar, the inverter configured to receive current via the second bus bar, wherein a height of the first bushing defines an air gap of approximately 5 millimeters between the first bus bar and the second bus bar. In one embodiment, the height of the first sleeve is about 5 millimeters. In one embodiment, the height of the second sleeve is about 1.8 millimeters. In one embodiment, the second bus bar includes a conductor secured to the first sleeve of the first bus bar, and the air gap is defined by a lower surface of the conductor and an upper surface of the first bus bar. In one embodiment, the first and second bus bars are oriented substantially perpendicular to each other. In one embodiment, the inverter drive assembly is mounted on an off-highway vehicle. In one embodiment, the at least one first sleeve is a pair of first sleeves. In one embodiment, the first bus bar is a laminated bus bar having a first layer and a second layer.

In another embodiment, provided is a bus bar for an inverter drive assembly of a vehicle. The bus bar includes a first layer; a second layer laminated to the first layer; at least one first bushing configured to receive a capacitor; and at least one second bushing configured to receive an inverter bus bar connected to an inverter of the inverter drive assembly, wherein the at least one second bushing is about 5 millimeters high. In one embodiment, a height of the second bushing defines an air gap between the first layer and the conductor of the inverter bus bar. In one embodiment, the air gap is about 5 millimeters high. In one embodiment, the at least one first sleeve is about 1.8 millimeters high. In one embodiment, the vehicle is an off-highway vehicle. In another embodiment, the vehicle is a locomotive. In one embodiment, the inverter bus bar is oriented substantially perpendicular to the bus bar.

In yet another embodiment, a method is provided. The method comprises the following steps: providing a first bus bar, connecting a second bus bar having a conductor to the first bus bar to define an air gap between the first bus bar and the second bus bar, wherein the air gap is substantially 5 millimeters. In one embodiment, the first bus bar comprises a first sleeve having a height of substantially 5 millimeters, the second bus bar comprises a conductor electrically connected to the first sleeve, and the air gap is a space between the first bus bar and the conductor. In one embodiment, the method may further include the step of connecting the second bus bar to the inverter and the first bus bar to the capacitor. In one embodiment, the first bus bar includes a second sleeve having a height of about 1.8 millimeters.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. While the dimensions and types of materials described herein are intended to define the parameters of the invention, they are by no means limiting and are exemplary embodiments. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. The terms "comprising" and "wherein" are used as the plain-to-equivalent expressions of the respective terms "comprising" and "wherein". Moreover, the terms "first," "second," "third," "upper," "lower," "bottom," "top," and the like are used merely as labels, and are not intended to impose numerical or positional requirements on their objects.

This written description uses examples to disclose several embodiments of the invention, including the best mode, and also to enable any person skilled in the art to practice the embodiments of the invention, including making and using any devices or systems and performing any incorporated methods.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural elements or steps, unless such exclusion is explicitly stated. Furthermore, references to "one embodiment" of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. Furthermore, unless explicitly stated to the contrary, embodiments "comprising," "including," or "having" an element or a plurality of elements having a particular property may include additional such elements not having that property.

As certain changes may be made in the embodiments described herein without departing from the spirit and scope of the invention herein involved, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only of the inventive principles herein and not to be construed as limiting the invention.

Claims

1. An inverter drive assembly comprising:

a first bus bar (100) having a plurality of bushings, including at least a first bushing (114) and a second bushing (116), the first bus bar configured to receive at least one DC link capacitor of the inverter drive assembly via the second bushing (116);

a second bus bar (120) electrically connected to the first bus bar (100) at the first sleeve (114); and

wherein a height of the first sleeve (114) defines an air gap (126) of 5 millimeters between the first bus bar (100) and the second bus bar (120);

the second bus bar (120) comprises a conductor (122) fixed to the first sleeve (114) of the first bus bar (100);

the air gap (126) is defined by a lower surface of the conductor (122) and an upper surface of the first bus bar (100);

the first and second bus bars (100, 120) are oriented perpendicular to each other;

the first busbar (100) is a laminated busbar having a first layer (110) and a second layer (112); wherein the first layer (110) and the second layer (112) completely overlap.

2. The inverter drive assembly of claim 1, wherein:

the first sleeve (114) has a height of 5 mm.

3. The inverter drive assembly according to claim 2, wherein:

the second sleeve (116) has a height of 1.8 millimeters.

4. The inverter drive assembly of claim 1, wherein:

the inverter drive assembly is mounted on an off-highway vehicle.

5. The inverter drive assembly of claim 1, wherein:

the at least one first bushing (114) is a pair of first bushings.

6. A bus bar (100) for an inverter drive assembly of a vehicle, comprising:

a first layer (110);

a second layer (112) laminated to the first layer (110);

at least one first bushing (114) configured to receive a capacitor; and

at least one second bushing (116) configured to receive an inverter bus bar connected to an inverter of the inverter drive assembly;

wherein the at least one second sleeve (116) is 5 millimeters high; and

wherein the first layer (110) and the second layer (112) completely overlap;

the height of the second bushing (116) defines an air gap (126) between the first layer (110) and a conductor of the inverter bus bar;

the at least one second bushing is configured to receive the inverter bus bar (120) in a perpendicular orientation relative to the bus bar (100).

7. The bus bar of claim 6, wherein:

the air gap is 5mm high.

8. The bus bar of claim 6, wherein:

the at least one first sleeve is 1.8 millimeters high.

9. The bus bar of claim 6, wherein:

10. The bus bar of claim 6, wherein:

the vehicle is a locomotive.