A mechanism for improved access to phase leads in an integrated motor controller

Abstract

The present invention introduces an integrated motor-controller unit for electric vehicles (EVs), wherein the phase leads (10) from the motor assembly connect directly to the power board via bus bars (20), secured by fasteners (80). The unit features access portions (70) on the housing, providing direct access to phase lead-power board bus bar connections through removable, water- resistant oil seals or end plugs (60) and O-rings (50), provided adjacent to the said connections for easy accessibility. Additionally, the fastener may comprise a clinching nut or a simple screw equipped with a circlip, that is designed to prevent the screw from falling out of its groove in the event of loosening.

Description

A MECHANISM FOR IMPROVED ACCESS TO PHASE LEADS IN AN INTEGRATED MOTOR CONTROLLERTECHNCAL FIELD

[0001] The present invention generally relates to the field of electric vehicle systems, particularly relating to integrated motor controller units also referred to as an integrated drive unit utilized in electric vehicles. More particularly, the invention relates to the incorporation of features for an improved mechanical arrangement that allow for easier access to key components, such as phase lead connections in the said units, without the need to disassemble the entire units, simplifying the maintenance process but also reducing the risk of damage to other components during service. Hence the present invention addresses solutions to optimize the positioning and accessibility of phase leads in integrated drive units, where the motor and controller are combined into a single assembly, to create a more compact, efficient, and serviceable unit.BACKGROUND OF THE INVENTION

[0002] The evolution of electric vehicles (EVs) has seen significant advancements in motor and controller technology, aiming to enhance efficiency, reduce size and weight, and improve the overall performance of the drive system. Traditionally, electric motors and their controllers have been designed as separate components, each housed in its own enclosure and connected via external wiring. While this approach allows for modularity and flexibility in design, it also introduces several challenges, such as increased complexity in assembly, larger physical footprint, and potential inefficiencies in thermal management.

[0003] In conventional electric vehicle systems, the motor and controller are separate units connected by extensive wiring. This setup often results in power losses due to long cables and requires a more complex cooling system, as both components generate heat that must be managed independently. The assembly process is cumbersome, with external cables necessitating additional space and extending the overall length of the motor-controller assembly. Moreover, the placement of these cables can obstruct the cooling fins on thecontroller, diminishing their effectiveness and increasing the risk of overheating, thereby impacting the system's overall efficiency and reliability.

[0004] Recent developments in integrated motor-controller configurations have focused on addressing these challenges by optimizing the positioning and connection of phase leads, as well as improving the overall layout of the controller within the motor assembly. Patent literature US9768672B2 relates to a method for integrating a traction motor and an inverter in a compact and efficient manner, providing a traction motor with a motor housing and coil winding, and an inverter with an inverter housing and an IGBT module. The inverter is independently installed within its housing, forming an interface comprising a mechanical interface for physical attachment and a high-voltage power interface for electrical connectivity. The mechanical interface is used to mount the inverter housing onto the motor housing, creating a unified assembly. The high-voltage power interface establishes an electrical connection between the coil winding of the traction motor and the IGBT module of the inverter.

[0005] The goal is to create a more compact, efficient, and serviceable unit that can deliver high performance while minimizing power losses and thermal issues. One of the most significant innovations in this area is developing a more compact design for the integrated motor controller unit that does not extend beyond the unit’s footprint. Additionally, the integration of the control board (CB) and power board (PB) within the motor assembly has led to more efficient power conversion and distribution, further enhancing the performance and reliability of the system.

[0006] While integration offers numerous benefits, it also raises concerns about the ease of maintenance and repair. In conventional systems, accessing and servicing the motor or controller components often requires disassembly of both units, which can be time-consuming and costly. There exists a need for an improved design that allows easy access to phase lead connections while maintaining the benefits of integration and ensuring proper environmental protection. To address this issue, the present invention has incorporated features that allow for easier access to key components, such as phase lead connections, without the need todisassemble the entire unit. This not only simplifies the maintenance process but also reduces the risk of damage to other components during service.OBJECTIVES OF THE INVENTION

[0007] A primary objective of the present invention is to provide an secure and serviceable connection between the power board busbars and the phase leads extending from the stator’s winding busbars from the integrated motor controller drive unit.

[0008] Another objective of the present invention is to implement a sealing mechanism comprising access portions in specific locations and incorporate removable seals in the integrated motor controller unit, that enables direct access to the said phase lead connections.

[0009] Another objective of the present invention is to achieve a high level of ingress protection for the integrated motor-controller unit, ensuring it is dust-tight and water-resistant, while maintaining efficient thermal management and minimizing power losses.

[0010] Yet another objective of the present invention is to reduce maintenance time and complexity, minimize the risk of component damage during servicing, enable quick access to critical connections and to maintain seal integrity through O-ring design.

[0011] Other objects of the present invention, as well as particular features, elements and advantages thereof, will be clarified in or be apparent from the following description and the accompanying figures.SUMMARY OF THE INVENTION

[0012] The following summary is provided to facilitate a clear understanding of the new features in the disclosed embodiment and it is not intended to be a full, detailed description. A detailed description of all the aspects of the disclosed invention can be understood by reviewing the full specification, the drawing and the claims and the abstract, as a whole.

[0013] An aspect of the present invention focuses on an innovative approach to enhancing accessibility and serviceability to the connections between the phase leads and the power board PCB in an integrated motor controller unit utilized in electric vehicles (EVs). The integrated motor-controller drive unit comprises two main sections: the motor assembly at the bottom and the controller assembly at the top. The phase leads from the motor assembly are linked to the controller assembly through bus bars, secured via fasteners, ensuring a solid connection while optimizing space and cooling efficiency.

[0014] A further aspect of the present invention is an access portion extruded / included on the housing of the integrated unit, which provides direct access to the said phase lead connections for easier maintenance and service. Technicians can access these connections without completely separating the motor and controller assemblies by removing the strategically placed RYB end plugs or oil seals, which also incorporate O-rings for dust-tight and water-resistant protection. This configuration simplifies disassembly and reassembly, reducing downtime and making the unit more serviceable and efficient.

[0015] Another aspect of the present invention is that the configuration of the present invention not only improves serviceability but also enhances the overall durability and reliability of the system. The use of removable seals and end plugs, which provide ingress protection, contributes to the longevity of the unit by preventing environmental factors like dust, debris and water from affecting the internal components. A method of assembly of the integrated motor controller unit utilizing the seal mechanism comprising of the access portion, end seal / oil seal is also disclosed thereof.BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The detailed description is described with reference to the accompanying figures. Throughout the drawings, the same drawing reference numerals will be understood to refer to the same elements and features. The features and advantages of the present proposed systemwill become more apparent from the following detailed description a long with the accompanying figures, which forms a part of this application.

[0017] Figure. 1 illustrates an integrated motor controller unit also referred to as an integrated drive unit utilized in electric vehicles, according to an embodiment of the present invention.

[0018] Figure. 2 illustrates yet another view of the integrated motor controller unit depicting busbars from the power PCB and phase leads extending from the motor of the integrated motor controller unit according to an embodiment of the present invention.

[0019] Figure.3 illustrates the phase leads extending from the stator of the motor assembly and connected via the stator busbars to the power board busbars utilizing fasteners according to an embodiment of the present invention.

[0020] Figure.4(a), 4(b) illustrates a close-up view of the sealing mechanism comprising an access portion, an O-ring and removable seal provisioned for accessing the RYB phase leads connected to the power board busbars within the integrated controller motor unit according to an embodiment of the present invention.

[0021] Figures.5(a), 5(b) illustrate schematic views of the oil seal or end plugs used to seal the access portion, according to an embodiment of the present invention.

[0022] Figure.6 illustrate an assembly of the integrated controller-motor unit according to an embodiment of the present invention.

[0023] Figure.7 illustrates the cross-sectional view of the fastener utilized to connect the power board busbar to the phase leads, according to an embodiment of the present invention.

[0024] It is to be noted, however, that the appended drawing illustrates only typical embodiments of this system and are therefore should not be considered limiting of its scope, for the system may admit to other equally effective embodiments.REFERENCE NUMERALS100 - Integrated motor controller unit10 - Phase leads (Red, Blue, Yellow)20 - Power Board Bus bars30 - Power Board / Power PCB40 - Stator bus bar50 - O-Ring60 - Oil seal / End plug / Plastic seal70 - Access portion80 - Fastener90 - slot or hole110 - Control Board / Control PCBDETAILED DESCRIPTION

[0025] The following is a detailed description of the present disclosure depicted in the accompanying drawings. However, it may be understood by a person having ordinary skill in the art that the present subject matter may be practiced without these specific details. The subject matter of the disclosure will be more clearly understood from the following description of the embodiments thereof, given by way of example only with reference to the accompanying drawings, which are not drawn to scale.

[0026] If the specification states that a component or a feature “may” or “can” be included, that particular component or feature is not required to be included or have the characteristic. The use of open-ended terms like “comprising” and variations herein is meant to encompass the steps listed thereafter and equivalents thereof as well as additional items. As used herein,the singular forms “a,” “an,” and “the” designate both the singular and the plural, unless expressly stated to designate the singular only.

[0027] The terms “comprise”, “comprising”, “includes”, “including”, “containing”, 0“ characterized by”, “having” or any other variation thereof, are intended to cover a nonexclusive inclusion.

[0028] The terms “preferred” and “preferably” refer to embodiments of the invention that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the invention.

[0029] An integrated motor controller unit (IMCU) in an EV (Electric Vehicle) refers to a system where the motor and its controlling electronics are combined into a single, cohesive unit. This design is aimed at enhancing efficiency, reducing complexity, and improving reliability in electric vehicle powertrains. A “Power PCB” is a specialized printed circuit board responsible for managing high-power electrical components and power conversion in electric vehicle systems. A “Control PCB” is a specialized printed circuit board responsible for managing the logic, control, and low-power electronic functions in an electric vehicle's system. “Phase leads” are the electrical connection points or power terminals that extend from the motor's stator windings, typically color-coded as Red (R), Yellow (Y), and Blue (B), used to transmit electrical power to drive the electric motor. An “IP67 rating” indicates that a product is waterproof and protected against dust and water. The term “Power Board” and “Power PCB” has been used interchangeably. The term “Control Board” and “Control PCB” has been used interchangeably.

[0030] In electric vehicles (EVs), the integration of the motor and controller assemblies as a cohesive unit is a common practice. However, the innovation in this design lies in the specific manner in which the integration is achieved, particularly in the positioning of phaseleads and the assembly structure that allows for easier serviceability. In a traditional setup, the motor and controller assemblies are two separate components that are attached together. The connection between the motor and controller assemblies are made typically by running cables over the controller assembly, which disrupts the fin arrangement on the controller's surface, leading to suboptimal cooling. Additionally, the connections require extra space, causing the motor to extend further beyond the controller assembly, and complicating the design and assembly. Due to the wiring requirements, the motor assembly does not terminate at the controller but extends further, occupying more space.

[0031] The present invention relates to an integrated motor controller drive unit (100) unit is composed of two main sections: the motor assembly section at the bottom and the controller assembly section at the top as illustrated in Figure.1. Within the controller assembly of the integrated motor controller unit (100), there are two integrated printed circuit boards (PCBs). The power PCB or power board (30), comprises high power components like MOSFETS, IGBTs and heat dissipating devices. The control PCB (110) is responsible for handling low power control circuitry and feedback communication, like microcontrollers, sensors, communication chips, and signal pathways . Together, these two PCBs are stacked to form a cohesive controller assembly. In the integrated motor controller drive unit, the phase leads are positioned so as to connect the drive unit to the electric motor.

[0032] Figure.2 illustrates the three phase leads (red -R, yellow -Y, blue -B) collectively labelled as (10) in the IMCU. Here, the power PCB (30) is positioned inverted and the power PCB busbars (20) are seen to extend downwards. The busbars (20) of the power PCB (30) are designed to connect to the phase leads (10), extending upward from the stator busbar (40) for transferring power efficiently and reliably between the motor and the controller assemblies. The motor unit comprises of the stator, rotor, and windings. The stator winding busbar (40) is part of the motor's electrical system, connecting directly to the motor's windings (coils) for phases leads U, V, and W (10). During assembly, the busbars (20) of the power PCB (30) are aligned with the phase leads (10) to enable a secure connection utilizing fastener

[0033] Fig.3 displays the stator busbars (40), from which the phase leads extend upwards. The phase leads (10) from the motor are secured to their respective slots in the power board busbars (20), using fasteners as illustrated in Figure 3. The power board PCB (30) is inverted and features three bus bars (20), where the RYB phase leads (10) are aligned with and tightened with fasteners, ensuring a robust connection to the power PCB. For easier access and serviceability, an access portion (70) is incorporated into the housing of the motor controller drive unit, the portion being adjacent to each of the slots, as shown in Figure.4.

[0034] The present invention focuses on enhancing accessibility and ease of serviceability through a sealing mechanism incorporated in integrated motor controller drive systems, the control PCB (110) and power PCB (30) are integrated in a stacked configuration. The present invention further throws light on one of the key features, which is the sealing mechanism. This mechanism depicts an access portion (70) that is provided on the housing of the integrated motor controller drive unit (100). Figure. 4(a), 4(b) illustrates that each of the the access portion (70) of the integrated drive unit (100) is strategically placed adjacent to the fastener that connects each of the phase leads terminals (10) with the bus bars (20) of the power board. These access portions (70) are often cut in a circular shape, and positioned on the outer housing of the integrated motor controller unit (100).

[0035] A modular view of the integrated motor controller unit (100) focussing of the sealing mechanism and servicing aspects of the phase lead connections is illustrated in Figure.4(a), 4(b). The figure focusses on the access section (70) which provides direct access to the specific location and layout of the fastener connections (80) within the access section (70). It is clearly noted that a technician can directly access the fastener of the phase lead connection via the access portion (70) as the access portion provides a streamlined pathway for accessing critical components, securing the phase lead connections, facilitating efficient maintenance and servicing. . The access portion (70) is further sealed with an end seal (60) and with an O-ring (50). The end seal (60) can be an oil seal or plastic seal. This eliminates the need to separate or disturb the integrated motor controller unit (100), during routineservicing or maintenance of the motor. Technicians can simply remove the seal assemblies — three in total, including the RYB oil seals and their respective O-rings, as well as the water seal — to gain access.

[0036] As seen in Figure.4(a),4(b), the single sealing mechanism comprises of the access portion (70), end seal (60) and an O-ring (50). The access portion (70) offers an easy access to the internal phase connections without requiring extensive disassembly, as it facilitates a direct interface with the connection hardware. The end seal (60) is positioned at the outermost part of the access section, preventing the ingress of contaminants such as oil or moisture. The end seal (70) can be either an oil- or water-resistant seal based on rubber or plastic, depending on the requirements. The O-ring (50) ensures a tight, leak-proof fit between the components, maintaining the internal environment's integrity while allowing for easy disassembly when required.

[0037] As seen in Figure.4(a), 4(b), the configuration comprises a total of three seals for the RYB (corresponding to the three-phase connections), comprising of three end seals made of rubber or plastic and their respective O-rings, and the water seal — without detaching the integrated motor controller unit. This modularity reduces the risk of damage to other components and ensures a more efficient servicing process.

[0038] Figures 5(a) and 5(b) illustrate detailed schematic views of the singular sealing mechanism comprising the oil seal / end plugs used to seal the access portion (70). Figure 5(a) provides a 3D cross-sectional view of the oil seal / end plug (60), as per an embodiment of the present invention, while Figure 5(b) presents a 3D schematic view of the same. The seal (60) is made from rubber or plastic and features an O-ring (50) housed in a groove along its periphery. Additionally, the seal includes a slot or hole (90) designed for the insertion of a screwdriver or tool in the centre, allowing for easy removal without requiring the dismantling of the entire motor controller unit. The seal is designed to fit snugly into the access portion (70) and the O-ring (50) helps to maintain a leak-proof assembly by providing a flexible yet tight seal.

[0039] Referring back to Figures 5(a), 5(b), this seal (60) provides a high level of ingress protection for the motor-controller unit (100), ensuring it remains dust-tight and water- resistant. The combination of the oil seal or end plug (60) with the O-ring (50) ensures reliable performance by maintaining the integrity of the sealed system while simplifying the process of servicing. During maintenance, these removable seals or end plugs (60) can be extracted, enabling technicians to loosen the fasteners without disturbing the integrated motor controller unit (100). This design simplifies the disassembly and reassembly process, making it more straightforward and efficient. By reducing the complexity of maintenance procedures, the design minimizes downtime, allowing the motor to be quickly returned to operation.

[0040] Figure 6 illustrates an assembly of the integrated controller-motor unit (100) according to an embodiment of the present invention. Initially, the phase leads (10) extending from the stator busbars (40) are connected via the bus bars (20) of the power board (30). Unlike conventional nut and screw connections, which are unsuitable due to the risk of the nut falling into the assembly and being difficult to retrieve, the present invention utilizes fasteners (80) such as clinching nuts or screws with circlips, as also shown in Figs. 4 and 7. These fasteners ensure secure and reliable connections between the power PCB busbars and the phase leads, while also enabling easy access for assembly and maintenance. Once installed, these fasteners cannot be removed by simply loosening them, enhancing the robustness and stability of the connection.

[0041] These said fasteners (80) like clinching nuts or screws with circlips enable the accessibility and serviceability of the connections between the stator phase leads (10) and the power board of the controller assembly that are made accessible through the access portion (70) of the integrated motor-controller unit (100), depicted in Figures 4 to 6. After assembly, a tightening screwdriver is used to secure the nuts. Subsequently, a series of the removable RYB end plugs or oil seals (60), each incorporating a removable O-ring (50), are inserted as depicted in Figure 6. A water seal (not shown) is also incorporated. Each end plug or oil seal along with O-ring is tightened and provides a tightening torque of 3.5 ± 0.5 Nm within the access portion (70), resulting in a total tightening torque of 9-12 Nm for the entire assembly.The end plugs are removed only when servicing the unit is necessary and otherwise remain undisturbed. This configuration provide protection against dust and water ingress, achieving an IP67 rating.

[0042] In the configuration depicted, the focus is on the positioning of the RYB phase leads and their integration with the control board (30), emphasizing ease of accessibility facilitated by the end plugs and O-rings. The control board is situated at the lower level, with the power board placed above it (not shown in the figure). The connection sequence begins with the stator winding, which is linked to the busbar. Next, the busbar is connected to the power PCB. Finally, the power PCB is connected to the control PCB via another busbar, located in the middle.

[0043] The control board is responsible solely for managing functions such as determining the amount of power and torque required, as well as controlling these parameters. The power board, on the other hand, handles the conversion of DC power from the battery into AC power suitable for driving the motor. The motor assembly operates on AC current, while the battery supplies DC current. Therefore, the power board includes components like MOSFETs that convert DC to AC. The converted AC power is then delivered to the motor assembly to drive its operation.

[0044] Figure 7 discloses a cross-sectional view of the power board busbar (20) and fastener (80). The phase leads (10) from the motor assembly are inserted into the busbars (20), and the fasteners (80) are tightened to secure the connection. As an additional embodiment, the clinching nut can be replaced by a simple screw equipped with a circlip. This circlip is designed to prevent the screw from falling out of its groove in the event of loosening. While the screw may loosen, the circlip ensures that it remains securely in place, preventing it from falling out of the assembly. This feature enhances the reliability of the connection and minimizes the risk of component loss during maintenance or operation.

[0045] The invention described offers several major advantages. The integration of access portions and removable seals allows direct access to phase lead connections withoutdisassembling the entire unit. This significantly reduces downtime during maintenance and minimizes the risk of damage to other components. Further, by directly integrating phase leads with the power board and optimizing the internal arrangement of the control and power PCBs, the system achieves a smaller physical footprint, improving spatial efficiency in electric vehicle assemblies. Also the compact layout ensures optimal positioning of cooling fins, reducing the risk of overheating and enhancing overall system reliability. With features like O-rings and removable seals, the unit achieves IP67 rating, ensuring it is both dust-tight and water-resistant, protecting internal components from environmental damage. Additionally, components such as clinching nuts and optional circlips ensure secure connections that remain fixed even during loosening, reducing maintenance complexity and preventing part loss.

[0046] The invention is not limited only to the embodiments described above and shown in the drawings, which primarily have an illustrative and exemplifying purpose. This patent application is intended to cover all adjustments and variants of the preferred embodiments described herein; thus, the present invention is defined by the wording of the appended claims and the equivalents thereof. Thus, the equipment may be modified in all kinds of ways within the scope of the appended claims.

Claims

WE CLAIM:

1. An integrated motor controller drive unit (IMCU) for electric vehicles comprises: a power printed circuit board (power PCB) (30) positioned within the IMCU; power board busbars (20) extending from the power PCB (30); phase leads (10) extending from stator busbars (40 within a motor assembly section; and a fastener (80) configured to secure the said phase leads (10) to the said power board busbars (20); an access portion (70) provided adjacent to each fastener (80), the access portion (70) enabling a direct access to each phase lead (10); and a sealing mechanism configured to seal each access portion (70) of the integrated unit (100).

2. The integrated motor controller drive unit as claimed in claim 1, wherein the said sealing mechanism comprises an end plug (60) and or water seal configured to seal the access portion (70); an O-ring (50) disposed within a peripheral groove of the end plug (60), wherein the O-ring (50) ensures a leak-proof and secure fit of the end plug within the access portion (70); and a central slot or hole (90) formed on the surface of the end plug (60), the slot or hole (90) being adapted to receive a tool for easy removal of the end plug for servicing without requiring the disassembly of the motor controller unit.

3. The integrated motor controller drive unit as claimed in claim 1, wherein the end plug (60) is being made of a durable material such as rubber or plastic.

4. The integrated motor controller drive unit as claimed in claim 1, wherein said fastener (80) is a clinching nut or a screw and screw equipped with a circlip.

5. The integrated motor controller drive unit as claimed in claim 1, wherein the tightening torque of each end plug is approximately 3.5 ± 0.5 Nm; and a total tightening torque of said end plugs is approximately 9 - 12 Nm, thereby providing secure and consistent connection.

6. A method for assembling an integrated motor controller drive unit (IMCU) for electric vehicles, the method comprising: positioning a power printed circuit board (power PCB) in an inverted manner within the IMCU; extending power board busbars (20) from the power PCB (30); positioning phase leads (10) extending from stator busbars (40) within a motor assembly section; connecting the phase leads (10) to the power board busbars (20) using a fastener (80); incorporating an access portion adjacent to each fastener (80), the access portion (70) enabling direct access to the corresponding phase lead (10); sealing each access portion with a sealing mechanism, the sealing mechanism comprising an end plug (60) and / or water seal with an O-ring (50) to ensure a leak-proof and secure fit; and configuring a central slot or hole on the end plug adapted to receive a tool for easy removal of the end plug, thereby enabling servicing of the phase leads without requiring disassembly of the motor controller drive unit.

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