Motor control unit for an electric vehicle

Abstract

A motor control unit (100) for an electric vehicle, comprising: a printed circuit board (PCB) (120) having a plurality of switching devices (250); a heat transfer assembly (150) configured to absorb heat generated by the plurality of switching devices (250); wherein the heat transfer assembly (150) comprises a plurality of thermal absorption blocks (300), each thermal absorption block (300) being spaced apart from one another and positioned to thermally contact a corresponding switching device (250) to absorb the heat generated by the switching devices

Description

[0001] MOTOR CONTROL UNIT FORAN ELECTRIC VEHICLE

[0002] FIELD OF INVENTION

[0003] The present invention relates to a motor control system for electric vehicles and more particularly relates to a motor control unit with improved thermal management features.

[0004] CROSS REFERENCE TO RELATED INVENTION

[0005] This invention takes priority from an earlier filed provisional patent application no. 202421095712 filed on December 04, 2024; which is incorporated herein as reference.

[0006] BACKGROUND

[0007] The demand for electric vehicles (EVs) has been growing rapidly, evolving from being seen merely as an environment friendly choice to becoming a strong competitor to traditional internal combustion engine (ICE) vehicles. With the evolving consumer expectations, there is an increasing demand for EVs that offer higher performance, particularly in terms of rapid acceleration and instantaneous high torque. These performance requirements emphasize the increasing significance of advanced motor control systems, which are essential for regulating power delivery to the electric motor and maintaining efficient and reliable vehicle performance.

[0008] As EV technology continues to advance, the demands on motor control systems have increased substantially, especially in terms of handling higher currents. Modern motor control units are now required to manage much greater power densities to meet the performance expectations of today’s electric vehicles. A key element in this process is the switching devices within the motor control unit, which play a crucial role in regulating power flow to the motor.

[0009] Switching devices, such as Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs), function as electronic switches that regulate the flow of current within the motor control circuit. To meet the high-performance demands of EVs, these switches must operate at high switching frequencies while managing substantial current levels. However, the combination of high-speed operation and large current handling often lead to excessive heat generation. The heat buildup in switching devices, particularly during high demand situations such as rapid acceleration, during emergency overtaking or peak torque conditions such as hill climbing, can pose a significant problem as the heat generated can be several times in comparison to the normal working conditions. Under these conditions, switching devices can experience substantial temperature rises, which if left unmanaged may lead to thermal runaway, a phenomenon where increasing temperatures further exacerbate the heat generation, ultimately resulting in component failure. This failure of switching devices, such as MOSFETs, due to excessive heat can lead to cascading failures in the motor control unit, potentially damaging other components and creating safety hazards. Such failures can also lead to vehicle downtime, reduced vehicle performance, and increased maintenance costs, outcomes that are highly undesirable. Hence, there is a need to provide a cooling system for MOSFETs.

[0010] Traditional cooling mechanisms, such as passive bottom cooled heat sinks, active cooling using fans, and liquid cooling systems, have been used to dissipate the heat generated by switching devices. In case of bottom cooling, heat sinks are arranged in the solder side, and this arrangement requires further modifications on the PCB such as thermal vias to carry the heat to the heat sink. However, these solutions have its limitations as they fail to dissipate the heat at a rapid rate and is having a bulky setup. Conventional top mounted heat sinks, while effective in increasing the surface area for heat dissipation, requires significant space and add complexity to the system. This makes them unsuitable for space constrained applications commonly found in modern EV designs. Additionally, conventional top mounted cooling solutions can be both costly and time consuming to assemble, as complex measures need to be taken to avoid damaging the components of a printed circuit board (PCB) during assembly. Moreover, top-mounted cooling solutions may require fixation to both the printed circuit board (PCB) and the heat sink itself. Given these challenges, existing designs often fail to provide adequate cooling under high thermal conditions, leaving switching devices vulnerable to overheating and failure in operational scenarios. Further the heat build-up when left unchecked even hampers the normal operational conditions and deteriorates the longevity of the components.

[0011] Hence, there is a need in the existing art for an efficient, cost-effective cooling mechanism that is capable of addressing high thermal loads and is also suitable for integration into compact, space constrained motor control systems in electric vehicles in a cost-effective manner. OBJECTIVES

[0012] The object of the present invention is to provide an electric vehicle (EV) motor control system.

[0013] Another object of the present invention is to provide a motor control system for electric vehicles with enhanced heat management capabilities.

[0014] Yet another object of the present invention is to develop a motor control housing that supports effective cooling and provides robust protection against dust and water ingress.

[0015] Another object of the present invention is to provide a thermal management system that minimizes production costs.

[0016] A further object of the present invention is to reduce assembly time by simplifying the integration process and minimizing the need for complex or time-consuming assembly steps.

[0017] A further object of the present invention is to provide a strategic arrangement and integration of components within a motor control unit.

[0018] These and other objects and advantages will become more apparent when reference is made to the following description and accompanying drawings.

[0019] SUMMARY:

[0020] The present disclosure relates to a motor control unit for an electric vehicle, the motor unit comprising: a printed circuit board (PCB) having a plurality of switching devices mounted on it; a heat transfer assembly configured to absorb heat generated by the switching devices; wherein the heat transfer assembly comprising a plurality of thermal absorption blocks, each thermal absorption block being spaced apart and in thermal contact with a corresponding switching device to absorb the heat generated by the switching devices. The heat transfer assembly comprises a sheet metal plate, and the plurality of thermal absorption blocks are preferably mounted to the sheet metal plate using a plurality of compressible bushes or springs and the thermal absorption block being in contact with a top surface of the switching device.

[0021] The compressible bushes accommodate tolerances, ensuring consistent thermal contact with the switching devices, preventing structural damage to the switching devices, and absorbing vibrations and mechanical shocks.

[0022] The thermal absorption block includes a thermal interface material disposed on at least one of a side facing the corresponding switching device or on side facing the motor control housing for enhanced thermal conduction and electrical insulation.

[0023] The switching device may be a MOSFET, IGBT, FET. a metal-oxide-semiconductor fieldeffect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or a field-effect transistor (FET).

[0024] The switching devices can operate at a switching frequency of 10 to 50 KHz and configured to handle current in a range 0 to 500 amp.

[0025] The number of thermal absorption blocks is equal to the number of switching devices mounted on the PCB and the thermal absorption blocks are made of a metal with high thermal conductivity such as copper or aluminium.

[0026] The thermal absorption blocks are of a shape covering maximum surface area of the switching device and preferably of a square shape having mounting provisions in its corners. In another embodiment, surface facing the top side of the switching device of the thermal absorption blocks may be flat, while the surface facing motor control housing may be concave or convex for better mating with the inner surface of the motor control housing.

[0027] The thermal absorption block is having surface facing motor control housing is adapted to be of flat, concave or convex shape to mate with a corresponding inner surface of a motor control housing.

[0028] The PCB is having defined inverter section capable of handling high three phase-current wherein switching devices are arranged in a zigzag track opposite and the plurality of switching devices is positioned in a track arranged diagonally and opposite in a zigzag pattern configured to reduce current path resistance.

[0029] The heat sink is a motor control housing designed into two parts with sealing means to enable operation in various environmental conditions without compromising performance.

[0030] The motor control unit is enclosed in a motor control housing, wherein the motor control housing is formed of two parts joined by sealing provision to prevent dust and moisture ingress. The motor control housing is formed of metal such as aluminium.

[0031] The motor control housing is having an inside surface and an outside surface, wherein the inside surface of the motor control housing includes a plurality of protrusions and depressions designed to accommodate the heat transfer assembly, and the outside surface is equipped with a plurality of fins to enhance airflow and increase surface area for improved air-cooling efficiency. The motor control housing is made of metal including aluminium.

[0032] According to an, the motor control unit is connected to an electric vehicle; wherein the motor control unit is configured to regulate the electrical supply to the electric motor from a power source.

[0033] BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and other objects, features, and advantages of the present invention will be more apparent from the detailed description taken in conjunction with the accompanying drawings, in which:

[0035] Fig. 1A illustrates an exploded view of a motor control unit assembly according to an embodiment of the present disclosure;

[0036] Fig. IB illustrates an exploded view of the arrangement of a PCB, a heat transfer assembly and a motor control housing according to an embodiment of the present disclosure;

[0037] Fig. 2 illustrates an isometric view of the heat transfer assembly according to an embodiment of the present disclosure;

[0038] Fig. 3A illustrates a top view of the PCB configured without the heat transfer assembly according to an embodiment of the present disclosure;

[0039] Fig. 3B illustrates a top view of the PCB configured with the heat transfer assembly according to an embodiment of the present disclosure; Fig. 4A illustrates a top view of an inner surface of the motor control housing according to an embodiment of the present disclosure; and

[0040] Fig. 4B illustrates a bottom exploded view of an outside surface of the motor control unit assembly according to an embodiment of the present disclosure.

[0041] REFERENCE NUMERALS

[0042] 100 - Motor control unit assembly

[0043] 120 - PCB

[0044] 150 - Heat transfer assembly

[0045] 200 - Motor Control Housing

[0046] 210 - Inner Surface of Motor Control Housing

[0047] 220 - Outside surface of Motor Control Housing

[0048] 250 - Switching devices

[0049] 300 - Thermal absorption blocks

[0050] 350 - Rubber bushes

[0051] 400 - Sheet metal plate

[0052] 450 - Protruding elevation of Motor Control housing

[0053] 500 - Depression of Motor Control housing

[0054] 550 - Fins of Motor Control

[0055] 600 - Sealing provision of Motor Control housing

[0056] DETAILED DESCRIPTION:

[0057] In the following description, for purposes of explanation, specific details are set forth to provide a thorough understanding of embodiments described herein. It will be apparent to those skilled in the art that the embodiments described herein may be practiced without some of these specific details. The examples and descriptions are provided to clearly communicate the concepts of the disclosure and are not intended to limit the scope of the embodiments described herein. On the contrary, the intention is to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the appended claims. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment described herein. The appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics described in connection with one embodiment may be combined in whole or in part with those of other embodiments, as appropriate and as would be understood by a person skilled in the art.

[0058] To the extent that the terms “includes,” “has,” “contains,” and other similar expressions are used in this specification or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising,” as an open transition word that does not preclude the presence of additional elements or steps. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will further be understood that the terms “comprises” and / or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the expression “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0059] Positional or directional terms such as “top,” “bottom,” “front,” “rear,” “left,” “right,” “upper,” “lower,” “horizontal,” “vertical,” and similar expressions are used in this specification for ease of description and illustration only, and do not limit the orientation or position of any component or feature unless explicitly stated otherwise. Such terms are to be construed as relative references intended to facilitate understanding of the embodiments described herein and may encompass different orientations or positions in actual use or manufacture.

[0060] Specific details are provided in the following description to facilitate a thorough understanding of the embodiments described herein. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, well-known components, circuits, structures, and arrangements may be illustrated without unnecessary detail so as not to obscure the embodiments.

[0061] FIG. 1 A illustrates an exploded view of a motor control unit assembly (100) of an electric vehicle. A motor serves as the primary driving force, converting electrical energy into mechanical energy to initiate and sustain the operation of the electrical vehicle. A motor control unit (MCU) is a critical component, responsible for managing and regulating the motor's operation. This unit ensures that the motor operates efficiently under varying conditions by controlling key parameters of the motor such as power supply, speed, torque, and direction of rotation. By adjusting these parameters, the MCU maintains optimal performance of the motor, compensating for changes in load or operating conditions. For operation, the MCU may include various circuit elements such as drivers, controllers, and feedback systems, which enable dynamic regulation of motor performance. The MCU may also incorporate safety mechanisms such as overload protection, thermal protection, and fault detection to safeguard the motor and prevent damage during operation.

[0062] FIG. IB illustrates an exploded view of the arrangement comprising a PCB (120), a heat transfer assembly (150), and a motor control housing (200), according to an embodiment described herein. The PCB (120) serves as a central component of the motor control unit (MCU). It typically includes distinct sections that perform specialized functions. For example, the inverter section of the PCB is responsible for handling high-voltage signals to convert DC power from battery into the power required by the motor. Other sections of the PCB (120) houses various electronic components such as microcontrollers, drivers, sensors, capacitors, resistors, and other circuitry that controls the motor's operation. Given the critical role of these electronic components, it is essential that the PCB (120) and its associated electronics are protected from environmental factors such as dust and water ingress, which may cause malfunction or degradation of the components over time. To address this, the system is designed with a sealed motor control housing (200) that encloses the PCB (120) and the electronic components. This motor control housing (200) is designed in a two-part form that can be sealed together by fastening means such as nuts and bolts to provide protection against external contaminants while also offering structural support to maintain the integrity of the components during operation. In addition to protection from environmental factors, a heat transfer assembly (150) is integrated modularly to the motor control housing (200). The heat transfer assembly (150) facilitates the dissipation of heat generated by the high-power electronic components, particularly in the inverter section, ensuring that the system operates within safe temperature limits.

[0063] According to an embodiment described herein, a motor control unit (MCU) is operatively connected to an electric vehicle. The motor control unit is configured to manage and regulate the electrical power supplied from a power source such as a battery pack or energy storage system to the electric motor. This regulation includes controlling parameters such as voltage, current, and frequency to ensure optimal motor performance, energy efficiency, and vehicle drivability under varying load and environmental conditions. The motor in an electric vehicle (EV) is controlled by the motor control unit (MCU), which regulates the power supplied to the motor. This regulation can be achieved through various techniques, such as linear control or pulse width modulation (PWM). In linear control, a variable resistor is placed in series with the motor, and the resistance is adjusted to vary the voltage applied across the motor. This approach, however, is less efficient, especially at higher power levels, due to the significant energy lost as heat in the resistor. Alternatively, in pulse width modulation (PWM), the voltage applied to the motor is varied by rapidly switching a semiconductor device, such as a transistor, on and off at a high frequency. The effective voltage applied to the motor is determined by the ratio of on time to off time, commonly referred to as duty cycle. By adjusting the duty cycle, the MCU can control the average power delivered to the motor.

[0064] However, this high-frequency switching introduces significant thermal losses due to the switching action of semiconductor devices like Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) or Insulated-Gate Bipolar Transistors (IGBTs). Each time, a switching device transitions from on to off or vice versa, energy is dissipated as heat. Over time, this heat build-up can lead to overheating of components and potentially cause component failure if not properly managed. To mitigate this risk, the system includes the heat transfer assembly (150), which is designed to efficiently dissipate the heat generated by the switching devices (250) according to an embodiment of the invention. The heat transfer assembly (150) transfers the heat from the switching devices (250) to the motor control housing (200) acting as a heat sink, which then disperses the heat into the surrounding environment. This thermal management system is critical to maintaining the reliability and performance of the motor control unit, preventing thermal damage to the electronic components and ensuring safe operation of the electric vehicle.

[0065] FIG. 2 illustrates an isometric view of the heat transfer assembly (150). The heat transfer assembly (150) includes a sheet metal plate (400), which serves as a structural base for mounting the other components. The thermal absorption blocks (300) are mounted on bushes made of compressible material, which facilitates proper alignment and damping. The proper alignment ensures that the thermal contact is maintained for effective heat transfer. According to an embodiment, the compressible bushes are rubber bushes (350), providing both flexibility and vibration damping, which helps maintain the integrity of the assembly during operation. In another embodiment, the thermal absorption blocks (300) may be mounted on springs, allowing for further vibration isolation and ensuring that the thermal blocks remain in contact with the heat-generating components, even under varying mechanical stresses or thermal expansion.

[0066] In an embodiment, the sheet metal plate (400) is designed with a plurality of defined cavities to align with the inner surface of the motor control housing (200). These cavities are shaped to provide a secure and precise fit to optimize thermal contact between the components. Additionally, the sheet metal plate (400) includes holes that facilitate the fastening of the sheet metal plate (400) to the motor control housing (200). These holes are also used to mount the thermal absorption blocks (300), which are secured through the compressible bushes (350), ensuring that the thermal absorption blocks (300) are firmly held in place during operation. In an embodiment, the sheet metal plate (400) is provided with grooves that mate with corresponding features on the inner surface of motor control housing (200). These grooves help guide the plate into position and provide additional thermal contact surface area, enhancing the overall heat dissipation efficiency of the assembly. However, any other suitable fastening mechanisms may be used for mounting the sheet metal plate (400) on the inner surface of the motor control housing (200) or may also be provided as an integral part of the motor control housing (200).

[0067] In another embodiment, the thermal absorption blocks (300) are made of copper metal and is having a square shape with mounting provisions on its four corners. In an instance, the rubber bushes (350) are fixed to the thermal absorption blocks (300) in a snap fit manner and in another instance, the rubber bushes (350) are glued to the thermal absorption blocks (300). In one embodiment, the thermal absorption blocks (300) are circular in shape, which allows for efficient contact with the heat-generating surfaces of the switching devices (250). The size of each thermal absorption block (300) is specifically chosen to match the dimensions of the switching devices (250). This ensures that the thermal blocks are optimally positioned to absorb and dissipate the heat generated by the switching devices (250). This arrangement further ensures that the heat generated by the switching devices (250) are effectively transferred to the motor control housing (200) without needing a bulky and costly arrangement. Further, the optimal arrangement of having thermal absorption block (300) having spaced apart, ensures that heat transfer arrangement is not inferring with any other component of the PCB (120) thereby making the assembly process expeditious.

[0068] In an instance, the surface area of the thermal absorption blocks (300) may be increased or decreased relative to the size of the switching devices (250). By adjusting the surface area, the thermal absorption blocks can be tailored for better heat dissipation, depending on the thermal load and the specific requirements of the application.

[0069] In an embodiment, both surfaces of the thermal absorption blocks (300) are flat, providing a consistent and uniform contact surface for heat transfer. Alternatively, in another embodiment, one surface of the thermal absorption blocks (300) may be flat, while the other surface may be concave or convex for better mating with the corresponding inner surface of the motor control housing (200). This design choice further optimizes the contact area and improves heat transfer efficiency by ensuring a tight, uniform fit between the thermal absorption blocks (300) and the motor control housing (200). In an embodiment, the number of thermal absorption blocks (300) is equal to the number of the switching devices (250) mounted on the PCB (120). This one-to-one correspondence ensures that each switching device has its dedicated thermal absorption block (300) for efficient heat management.

[0070] FIG. 3 A illustrates the top view of the PCB (120) of the motor control unit assembly (100). The inverter section of the PCB (120) is responsible for converting direct current (DC) from the power supply into alternating current (AC) for the motor, or alternatively, for modulating the DC power to control motor speed and operation. This section is crucial for ensuring that the motor operates efficiently and within its specified performance parameters, such as speed, torque, and power delivery. In an embodiment, the inverter section of the PCB (120) includes six switching devices (250). The switching devices are arranged oppositely and diagonally on the PCB in a zig zag track to optimize the layout and reduce resistance in the power tracks, thus improving overall efficiency. In an embodiment, the switching devices (250) are MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) capable of handling a switching frequency of 10 to 50 KHz and handing current even up to 500 amp. In pulse width modulation (PWM), the voltage applied to the motor is varied by rapidly switching the MOSFETs on and off at a high frequency. The effective voltage delivered to the motor is determined by the duty cycle, or the proportion of time, the MOSFET is in on state versus off state. By adjusting this duty cycle, the motor’s speed and power can be regulated. However, MOSFETs tend to heat up during high frequency switching due to switching losses. These losses occur during transitions between the on and off states of the MOSFETs, where both voltage and current may overlap, resulting in power dissipation. As the switching frequency increases, the number of transitions per second also increases, which amplifies these losses and leads to more heat generation. This excess heat can cause thermal runaway, a condition where rising temperatures further increase power dissipation, potentially damaging the MOSFETs and compromising the system's stability. To mitigate the risk of overheating, an embodiment includes a heat transfer assembly (150), which is designed to efficiently transfer the heat buildup from the MOSFETs. The heat transfer assembly (150) helps manage the thermal load by dissipating it to the motor control housing (200) acting as a heat sink, preventing thermal damage and ensuring the safe and efficient operation of the motor control unit.

[0071] FIG. 3B illustrates top view of the PCB (120) of the motor control unit assembly (100) with the heat transfer assembly (150) in place. In an embodiment, the heat transfer assembly (150) is aligned with the PCB (120) such that the top surface of the switching devices (250) is in direct thermal contact with the first surface of the corresponding thermal absorption blocks (300). This alignment is crucial for effective heat transfer, as it ensures that the heat generated by the switching devices (250) is efficiently absorbed and dissipated by the thermal absorption blocks (300). To further enhance thermal conductivity and ensure a reliable thermal connection, a thermal interface material (TIM) is placed between the top surface of the switching devices (250) and the surfaces of the thermal absorption block (300). The thermal interface material helps to eliminate air gaps, which can significantly reduce heat transfer efficiency. Additionally, it provides electrical insulation, preventing any potential short circuits or other electrical hazards that may arise from direct electrical contact between the switching devices (250) and the thermal absorption blocks (300).

[0072] In an embodiment, the thermal interface material is a high-viscosity paste-like substance. This type of material is designed to offer both excellent thermal performance and electrical insulation properties. When the heat transfer assembly (150) is installed, the paste spreads out, filling any microscopic gaps between the surfaces, ensuring complete and continuous thermal contact between these components, thereby maximizing heat transfer efficiency.

[0073] FIG. 4A illustrates a top view of the inside surface of the motor control housing (200). In an embodiment, the motor control housing (200) is made of aluminium. The inside surface of the motor control housing (200) is designed with provisions to accommodate and securely fasten both the heat transfer assembly (150) and the PCB (120), ensuring stable positioning and optimal heat dissipation. In an instance, the inside surface of the motor control housing (200) is provided with grooves and protrusions, which are strategically placed to guide the installation of the heat transfer assembly and the PCB, ensuring proper alignment and minimizing movement during the operation. These features also help to increase the surface area for thermal contact, enhancing the overall efficiency of heat transfer. In another instance, the inside surface (210) of the housing (200) includes a protruding elevation (450), and a depression (500). In this configuration, the heat transfer assembly (150) is fastened onto the depression (500) of the motor control housing (200), securing it in place while ensuring thermal contact with the housing. The motor control housing (140) is formed of metal such as aluminium for light weight construction and enhanced heat dissipation.

[0074] In an embodiment, the surface of the thermal absorption blocks (300) is in direct thermal contact with the surface of the protruding elevation (450) of the motor control housing (200). This configuration allows for effective heat transfer from the thermal absorption blocks (300) to the motor control housing (200), further improving the heat dissipation capabilities of the system. To ensure optimal thermal conductivity between the thermal absorption blocks (300) and the motor control housing (200), a thermal interface material (TIM) is placed on the protruding elevation (450) and the depression (500).

[0075] FIG. 4B illustrates a bottom exploded view of the motor control unit assembly (100). In an embodiment, the motor control housing (200) comprises a plurality of fins (550) on its outside surface (220), which are specifically designed to enhance heat dissipation. These heat dissipation fins (550) increase the surface area of the motor control housing (200), allowing for more efficient transfer of heat from the internal components to the surrounding environment. The fins (550) are arranged in a manner that optimizes airflow and maximizes heat dissipation, providing a robust solution for maintaining the temperature of the motor control unit. A sealing provision (600) is provided in the forms of holes to fasten the parts of the motor control housing (200) using fastening means such as nuts and bolts.

[0076] Although certain exemplary embodiments have been described and illustrated, various features of separate embodiments may be combined to form additional embodiments not expressly shown or described. Furthermore, not all features, aspects, and advantages described herein are necessarily required to practice every embodiment. Accordingly, while the foregoing description has shown and described example embodiments to explain principles of the disclosure, various modifications, substitutions, and changes may be made by those skilled in the art without departing from the spirit and scope of the appended claims. The embodiments described herein are therefore to be considered in all respects as illustrative and not restrictive.

Claims

We Claim:

1. A motor control unit (100) for an electric vehicle, comprising: a printed circuit board (PCB) (120) having a plurality of switching devices (250) mounted on it; a heat transfer assembly (150) configured to absorb heat generated by the plurality of switching devices (250); wherein the heat transfer assembly (150) comprises a plurality of thermal absorption blocks (300), each thermal absorption block (300) being spaced apart from one another and in thermal contact with a corresponding switching device (250) to absorb the heat generated by the switching devices.

2. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the plurality of thermal absorption blocks (300) are mounted to a sheet metal plate (400) using compressible bushes or springs (128) to accommodate dimensional tolerances and to maintain consistent thermal contact with the switching devices (250).

3. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein each thermal absorption block (300) includes a thermal interface material disposed on at least one of a side facing the corresponding switching device (250) or on side facing the motor control housing (200) for enhanced thermal conduction and electrical insulation.

4. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the switching devices (250) includes one or more devices selected from a metal-oxide- semiconductor field-effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), or a field-effect transistor (FET).

5. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the switching devices (250) are operable at a switching frequency in a range of 10 kHz to 50 kHz and configured to handle a current in a range of 0 to 500 amperes.

6. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein each thermal absorption block (300) is formed of a metal having high thermal conductivity including copper or aluminium.

7. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein each thermal absorption block (300) has a shape configured to cover a maximum surface area of the corresponding switching device (250), and wherein the thermal absorption block (300) has a shape approximating a square with mounting provisions provided at its corners.

8. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the number of thermal absorption blocks (300) is equal to the number of switching devices (250) mounted on the PCB (120).

9. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the motor control unit (100) is enclosed in a motor control housing (200), wherein the motor control housing (200) is formed of two parts joined by sealing provision (600) to prevent dust and moisture ingress.

10. The motor control unit (100) for an electric vehicle as claimed in claim 8, wherein an inner surface (210) of the motor control housing (200) includes a plurality of protrusions (450) and depressions (500) configured to accommodate the heat transfer assembly (150), and an outside surface (220) including a plurality of fins (550) to enhance airflow and increase surface area for improved air-cooling efficiency.

11. The motor control unit (100) for an electric vehicle as claimed in claim 9, wherein each thermal absorption block (300) having surface facing motor control housing (200) is adapted to be of flat, concave or convex shape to mate with a corresponding inner surface (210) of a motor control housing (200).

12. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the PCB (120) includes an inverter section configured to handle three-phase current, and the plurality of switching devices (250) is positioned in a track arranged diagonally and opposite in a zigzag pattern configured to reduce current path resistance.

13. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the motor control housing (1 0) is formed of metal such as aluminium.

14. The motor control unit (100) for an electric vehicle as claimed in claim 1, wherein the motor control unit (100) is connected to an electric vehicle; wherein the motor control unit (100) is configured to regulate the electrical supply to the electric motor from a power source.

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