WO2025117198A1 - Electric pump unit and method for operating an electric pump unit with liquid submerged cooling of inverter - Google Patents

Abstract

An electric pump unit (400) comprising: an electric motor assembly (402); an inverter (401) coupled to the motor assembly; at least one inlet; and an outlet; wherein the electric pump unit is configured to: pump in oil from a sump through the at least one inlet and a gerotor assembly; cool the inverter by submerging the inverter in oil; and pump the oil to at least one vehicle system external to the electric pump unit. Method for operating such an electric pump unit.

Description

ELECTRIC PUMP UNIT AND METHOD FOR OPERATING AN ELECTRIC PUMP UNIT WITH LIQUID SUBMERGED COOLING OF INVERTER

CLAIM FOR PRIORITY

[0001] This application claims the benefit of priority of U.S. Provisional Application No. 63/603,447, filed November 28, 2023, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE DISCLOSURE

[0002] Inverters are important components for electric vehicles because of their contribution to the electric drive unit’s operation in the vehicle. Inverters convert direct current (DC) power from the battery to alternating current (AC) power, which is then used to drive the motor and enable the vehicle to move. However, to ensure maximal performance, electric drive units often contain cooling capabilities to prevent the inverter, motor, and gearbox from overheating and degrading itself, as well as other components within the system.

SUMMARY OF THE DISCLOSURE

[0003] According to one embodiment of the present disclosure, an electric pump unit can include an electric motor assembly; an inverter coupled to the motor assembly; an inverter; at least one inlet; and an outlet. The electric pump unit can be configured to pump in oil from a sump through the at least one inlet and a gerotor assembly; cool the inverter by submerging the inverter in oil; and pump the oil to at least one vehicle system external to the electric pump unit. In some embodiments, the sump can be a dry sump. In some embodiments, the at least one inlet comprises two independent inlets. In some embodiments, pumping in the oil from the sump can include pumping in the oil through both independent inlets. In some embodiments, the pump can include two gerotors to pump the oil.

[0004] In some embodiments, the sump can be a wet sump. In some embodiments, the gerotor assembly pressurizes the oil prior to the cooling of the inverter. In some embodiments, the pump can include a printed circuit board assembly (PCBA), the PCBA comprising at least one temperature sensor configured to measure temperature values of the oil. In some embodiments, the at least one temperature sensor resides at a lowest point of the PCBA. In some embodiments, the PCBA can include a channel at least partially surrounding the at least one temperature sensor. In some embodiments, the PCBA resides in a position that submerges the at least one temperature sensor in the oil. In some embodiments, the PCBA is conformally coated.

[0005] In some embodiments, the oil flows through the channel. In some embodiments, the electric pump unit can include an electronic control unit (ECU) configured to control the pump. In some embodiments, the ECU receives the measured temperature values from the at least one temperature sensor and controls the electric pump unit based on the received measured temperature values. In some embodiments, the ECU can be configured to cause the pump to maintain a consistent oil level of the oil.

[0006] According to another aspect of the present disclosure, a method for operating an electric pump unit that can include a gearbox and electric motor assembly and an inverted couple thereto can include storing oil in a sump; pumping, via the electric pump unit, the oil from the sump through at least one inlet and a gerotor assembly; cooling the inverter by submerging the inverter in the oil; and pumping, via the electric pump unit, of the oil to at least one vehicle system external to the electric pump unit. In some embodiments, the method can include measuring a temperature of the oil with at least one temperature sensor embedded in a printed circuit board assembly (PCBA) contained in the electric pump unit. In some embodiments, the method can include controlling the pump based on the measured temperature of the oil. In some embodiments, the at least one temperature sensor resides at a lowest point of the PCBA.

BRIEF DESCRIPTION OF THE FIGURES

[0007] Various objectives, features, and advantages of the disclosed subject matter can be more fully appreciated with reference to the following detailed description of the disclosed subject matter when considered in connection with the following drawings, in which like reference numerals identify like elements. [0008] FIG. 1 and 2 illustrate schematic diagrams of cooling and lubrication systems used to circulate a fluid through various components such as motor and gearbox of an electric drive unit of an electric vehicle.

[0009] FIG. 3 is an example prior art pump unit with inverter for an electric vehicle.

[0010] FIGS. 4A-4H illustrate an example pump unit for an electric vehicle with a submerged inverter according to some embodiments of the present disclosure.

[0011] FIGS. 5 A and 5B illustrate an example motor assembly for use within the pump unit of FIG. 4 according to some embodiments of the present disclosure.

[0012] FIG. 6 A is a cross-sectional view of a pump unit with a single gerotor assembly according to some embodiments of the present disclosure. FIG. 6B is a cross-sectional view of a pump unit with a double gerotor assembly according to some embodiments of the present disclosure.

[0013] FIGS. 7A-7B illustrate a pump unit with screen insert according to some embodiments of the present disclosure.

[0014] FIGS. 8 A and 8B illustrate example printed circuit board assemblies (PCBAs) for use within the pump unit of FIG. 4 according to some embodiments of the present disclosure.

[0015] FIGS. 9A-9H illustrate example flow paths of fluid throughout the pump unit of FIG. 4 according to some embodiments of the present disclosure.

[0016] FIG. 10 is an exploded view of a pump unit with a single gerotor assembly according to some embodiments of the present disclosure.

[0017] FIG. 11 is an exploded view of a pump unit with a double gerotor assembly according to some embodiments of the present disclosure.

[0018] FIG. 12 is an example method for operating the pump unit of FIG. 4 according to some embodiments of the present disclosure.

[0019] FIG. 13 shows a drive unit with a submerged inverter according to some embodiments of the present disclosure.

[0020] FIGS. 14A-14D show various drive units with submerged inverters according to some embodiments of the present disclosure. [0021] The drawings are not necessarily to scale, or inclusive of all elements of a system, emphasis instead generally being placed upon illustrating the concepts, structures, and techniques sought to be protected herein.

DESCRIPTION

[0022] The following detailed description is merely exemplary in nature and is not intended to limit the claimed invention or the applications of its use.

[0023] To enable this cooling capacity and adequate lubrication of the traction motor and gearbox, an oil-based system can be utilized in the drive unit. This fluid medium can be shared between the gearbox, motor, and the inverter for a cost-effective solution. Submerging the drive unit inverter in oil can unlock higher performance, continuous power and higher torque, within the same packaging space by improving the thermal capability of the inverter. This also enables to lower the BOM cost by eliminating parts for traditional heat sink designs and by selecting cheaper components that have a lower thermal limit. Benefits extend to making the system more efficient and reliable by keeping the temperature of the components lower and in the ideal operating range. Further, failure diagnostics controls can be implemented due to accurate temperature sensing by utilizing temperature sensors directly submerged in oil.

[0024] This system and method of the disclosed embodiment is not limited to only high voltage systems, 300 to 1000 V, but can also be extended to low voltage systems, below 60 V and take advantage of the benefits. One such system is an electric pump system in the drive unit that is utilized to circulate the same fluid medium within the entire drive unit. The pump has its own inverter and can exist within the packaging of the said electric pump system (although is not limited to this) and can be integrated with the drive unit inverter for further cost savings. Cooling the electric pump inverter can play an important role in achieving an optimal performance and reliability target of the system while maintaining low cost within a very small package. Further, although the embodiments described herein are in the context of an oil-based system, other fluids may be used. For example, any fluid that provides the adequate heat transfer, lubrication, and flow properties, for a particular application or pump size, may be used.

[0025] Challenges associated with designing such electric pump systems include designing a cost-effective pump system with low part count and high reliability for the product. Existing electric oil pump inverters are not directly oil cooled and require additional expensive parts such as thermal pads or heat sinks to operate in the desired temperature range with the dry inverter. A further byproduct is that traditional oil pumps have higher inaccuracies in measuring the oil temperature, with a complex system that frequently fails. For example, such techniques typically require many parts, sealing, and a complex firmware model to accurately predict the oil temperature. They therefore come with many possible failure points, such as on electrical connections, seals, and limitation on firmware prediction. Further, high volume production becomes quite complex with the addition of these components. Therefore, there is a need for an improved electric pump system, particularly with an oil cooled inverter, designed to work in conjunction with an electric traction motor.

[0026] FIGS. 1 and 2 illustrate schematic diagrams of cooling and lubrication systems 100 and 200 used to circulate a fluid, for example oil, through various components such as motor and gearbox of an electric drive unit of an electric vehicle. The system 100 utilizes a wet sump and the system 200 utilizes a dry sump. The system 100 includes a sump 101 that stores oil 103, which can be used to lubricate a gearbox 104 and a motor 105. A pump 102 pumps the oil from the sump 101 to lubricate the gearbox 104 and the motor 105. The system 200 includes a drive unit cavity 201 that houses a gearbox 204 and a motor 205. The system 200 also includes pumps 202 that transport oil from the external reservoir 203 to lubricate the gearbox 204 and the motor 205 and back to the external reservoir 203.

[0027] FIG. 3 is an example prior art pump unit 300 with inverter for an electric vehicle. Generally, such a pump unit 300 can be used to pull oil (or other fluid) from a sump (either wet or dry) and provide it to various components of an electric vehicle, such as the bearings, rotor, stator, and gears of a traction motor, among other places, in order to cool and lubricate them. The pump unit 300 can include an inverter cavity 301 (designed by the dashed lines) with an inverter and a cavity 302 that contains a gearbox and motor to operate the pump 300. In addition, the pump 300 includes an inlet 303 for fluid and an outlet 304 for fluid to exit. Moreover, an oil temperature sensor 306 resides within the inverter cavity 301. However, because the sensor 306 is so thermally disconnected from the oil, its sensing is prone to inaccuracies and generally performs sub-optimally.

[0028] Embodiments of the present disclosure therefore relate to systems and methods for liquid submerged cooling of electric pump inverters. The disclosed systems and methods offer an improved and more efficient cooling functionality for inverters. The disclosed systems and methods can utilize the oil in an electric drive unit that is typically used for the lubrication of drive unit components (e.g., the motor and gearbox) to also cool the pump inverter. In other words, the disclosed system shares the coolant (i.e., the lubrication oil) between the motor, gearbox, and pump inverter to both lubricate and cool the system. For example, the inverter of an electric oil pump can be submerged in oil via the pump cavity during operation so as to minimize the increase in temperature of such components. The disclosed pump system can apply to both wet and dry sump drive unit architectures.

[0029] In the drive unit with a wet sump architecture, oil can be pulled through a single suction point using the electric pump system, such as the one described in FIGS. 4A-4H, and distributed to various components such as bearings, rotor, stator, and gears of a traction motor, amongst other places, in order to cool and lubricate the traction motor. This oil drains back and accumulate in the sump (see FIG. 14B). An individual suction location can constrain the design of the drive unit housing to maintain oil level in various driving conditions. The electric pump system can utilize dual independent oil inlets in the pump (see FIG. 9G), which provides flexibility in housing design, control costs, and limit mass and packaging by expanding the reach of the pump inlets without changing the package of the pump itself (see FIG. 14 A). This can also avoid the cost associated with having two pumps to achieve the same performance requirement.

[0030] Dual independent oil inlets in the pump system can expand the capability to implement a dry sump architecture while minimizing the number of pumps used in the drive unit. It can enable different suction points in the drive unit which simplifies the housing design, mass, and packaging (see FIG. 14C). Further, it can ensure constant drainage of the different cavities of the drive unit which increases efficiency of the drive unit by avoiding oil windage losses. Independent dual inlet ensures that the liquid fed to cool the electric motor and lubricate the gearbox can reduce the risk of overheating or other reliability concerns with the gearbox running dry. Such benefits can be particularly useful in vehicle platforms where off-roading and racetrack conditions are common by enabling higher vehicle dynamic performance with higher g-forces and in extreme driving angles.

[0031] Architectures in the drive unit can be further optimized by maximizing pump performance to achieve the flow requirements for the system in various driving conditions while minimizing the number or size of the pumps required to minimize the system cost. Cooling the pump inverter by the same oil used for lubrication and cooling of the electric drive units can simplify the system design, enable cost saving by sharing the coolant medium, and unlock higher performance by directly cooling the inverter components.

[0032] Another benefit of the system and method of the disclosed embodiments, is that as the cooling capability of an electric pump inverter is increased. This means that more power can be pushed through the same inverter which enables a higher output for the same size pump system. This can allow higher performance from the pump system and provide more flow rate to the drive unit at the desired temperature range. This can further extend the thermal capability of the drive unit that translates to higher continuous power for the same size drive unit.

[0033] In an electric pump system, there is generally a strong relationship between the temperature of the inverter’s components and reliability of the system. Therefore, maintaining cooler temperatures and reducing the thermal cycling of the inverter’s components (e.g., MOSFETs, drivers, capacitors, resistors, etc.) can increase their usable lifetime. Generally, the higher the temperature such parts reach during operation, the more likely it is that they will fail over time.

[0034] Yet another benefit of increasing the cooling capacity of an inverter is that it can allow for cost savings, as it will enable selection of cheaper inverter components (that may have higher heat loss qualities or be rated with lower maximum temperatures). Additionally, operating at cooler temperatures can increase the efficiency of the PCBA and further reduce power consumption cost.

[0035] Moreover, such a configuration can enable a simpler, more accurate, and inexpensive reading of the oil temperature by having a temperature sensor directly embedded in the submerged inverter PCBA. With precise oil temperature, pump controls can be improved and additional features in the drive unit for refined failure diagnostics such as low oil detection can be achieved. Further, this can enable other potential features like adding a pressure estimate, oil health analysis, traction motor stator temperature prediction, filter degradation, and damaged hydraulic parts directly on the pump PCBA for optimal sensing capability, functionality, and cost. The system can also benefit from a faster feedback of accurate oil temperature in transient conditions to have more accurate and refined firmware feedback on the system.

[0036] FIGS. 4A-4H illustrate an example pump unit 400 for an electric vehicle with a submerged inverter according to some embodiments of the present disclosure. In some embodiments the pump unit 400 can include an inverter 401, a gearbox and motor 402, a shaft 403, an connector interface 404, an input section 405, an electric control unit (ECU) clip 406, a stator 407, a housing 408, an insulation displacement connector (IDC) pin connection 409, a gerotor assembly 410, a temperature sensor 411, and an outlet 412. Oil (or other liquid) can be supplied through one or more inlet(s) from the input section 405, which is then transported through the shaft 403. In some embodiments, the liquid can be oil taken from a sump, such as a wet or dry sump. The transportation of liquid throughout the pump unit 400 can allow for the submersion of the inverter 401. In some embodiments, when non-concentric parts of the motor 410 move, it can create a vacuum which pressurizes the fluid moving through it, pushing the liquid out. In some embodiments, the temperature sensor 411 can be contained within a PCBA. Additional details with respect to the flow of the liquid are discussed in relation to FIGS. 9A-9H, and additional details with respect to the PCBA containing the temperature sensor 411 are discussed in relation to FIGS. 8A and 8B.

[0037] FIG. 4B illustrates a top view of the pump unit 400 according to some embodiments of the present disclosure. In particular, the top view illustrates how the connector interface 404 extends from the top of the pump unit 400. FIG. 4C illustrates a bottom view of the pump unit 400 according to some embodiments of the present disclosure. In particular, the bottom view illustrates how the input section 405 feeds into bottom of the outlet 412. FIGS. 4D and 4E illustrate front and rear perspective views of the electric pump system 400 according to some embodiments of the present disclosure. In particular, the views illustrate how the connector interface 404 and the input section 405 extend, respectively.

[0038] FIG. 4F illustrates a side sectional view that particularly highlights the attachment of the components of the electric pump system 400 according to some embodiments of the present disclosure. ECU cover (not shown) can be attached to the pump housing 408 using ECU clip(s) 406. While only one such clip is shown, multiple clips could be used. In some embodiments, the stator 407 can be dropped into the heated pump housing 408 utilizing a thermal interference fit. This thermal process can also be optimized for cost and cycle time by dropping in the outlet 412 to the housing, reducing the need of additional parts such as bolts or separate processes. In some embodiments, as shown in FIGS. 4G and 4H, the winding of the stator 407 can be connected to the PCBA using an IDC pin 409 on the stator side and a press-fit pin on the PCBA side. The IDC pin 409 can be connected to multiple wire segments in the same pocket to allow for a compact, cost-effective, and flexibility on stator design, although this is not limiting or required. While each IDC pin 409 on the PCBA side has two press-fit tabs and three IDC pins 209 are used in this example design, it can be utilized with multiple IDC pins and different number of press-fit tabs based on the pump operating requirements.

[0039] FIGS. 5A and 5B illustrate the sectional view of the section 402 used in the electric pump system. As shown, section 402 includes stator winding 503, the shaft 403, stator lamination 504, rotor lamination 502, and bar magnets 501. In some embodiments, the shaft 403 can be a hollow shaft to allow for oil (or other liquid) to flow through it and reach the inverter 401, although this design is not limiting. In the case of a hollow shaft 403, the length can also be extended to push the oil directly on the inverter 401 to maximize the heat transfer and thus cooling of the inverter. Laminations 502 and 504 (i.e., for both the stator and rotor) can be utilized from the same stamping die to minimize costs. In some embodiments, a gap between the rotor and stator can be optimized to reduce the drag losses due to oil flow through the gap while minimizing the cogging torque and noise, vibration, and harshness (NVH) of the pump 400.

[0040] FIG. 6A illustrates the side view of the section 402 within the pump unit 400. FIG. 6B illustrates dual motors 410 and 600 that can enable dual independent inlets for both wet and dry sump architectures.

[0041] FIGS. 7A-7B illustrate a pump unit with screen insert 700 according to some embodiments of the present disclosure. In some embodiments, the mesh screen 700 can be integrated into the pump unit 400 of FIG. 4. For example, the mesh screen can be integrated within the input section 405 adjacent and feeding to the shaft 403 or any other feed paths.

[0042] FIGS. 8 A and 8B illustrate example PCBAs for use within the pump unit 400 of FIG. 4 according to some embodiments of the present disclosure. FIG. 8 A is an example PCBA 800 for use within the pump unit 400 of FIG. 4 according to some embodiments of the present disclosure. In some embodiments, the PCBA 800 can include an oil temperature sensor 801, which can be the same as or similar to the oil temperature sensor 411. The PCBA 800 can also include one or more MOSFETs 803. In some embodiments, the PCBA 800 can include six MOSFETs 803. In addition, the PCBA 800 can include a micro-controller 804, which can control the electric oil pump (not shown). In some embodiments, the PCBA 800 can also include a secondary oil temperature sensor 805 for redundancy and can refine firmware control logic. In some embodiments, all the components can be embedded/reside on a single side of the PCBA 500, saving cycling time, costs, and equipment space on the inverter manufacturing line. Moreover, FIG. 8B is an example PCBA 800 that can also be used within the pump unit 400. The PCBA of FIG. 8B is the same as or similar to that of FIG. 8A except that it also includes a conformal coating 806 over the various components. However, such coating is not a requirement and is only optional. In some embodiments, the conformal coating 806 can protect the various electrical components from oil and debris in the drive unit. This selection of the components and layout can enable uniform conformal coating which can help reduce the reliability risk and failures due to oil and contamination along with optimizing for high volume manufacturing and low cycle time. Further, single- sided layout can help reduce abrasive risk by directing contaminated oil from the shaft on the non-populated side of the board.

[0043] In some embodiments, the oil temperature sensor 801 and the slot 802 can reside at the lowest point on the PCBA 800 in vehicle orientation, to maximize the amount of time spent submerged in oil during operation of the drive unit. In addition, the PCBA 800 can include a slot 802, which can be a hollowed-out portion of the PCBA 800 that at least partially surrounds the oil temperature sensor 801. The slot 802 can reduce the thermal impact of other components (i.e., MOSFETs 803 and the controller 804) on the oil temperature sensor 801, which can increase the accuracy and reliability of its oil temperature readings. In addition, oil can flow through the slot 802, improving circulation on the top side of the PCBA 800 and ultimately enabling more accurate and reliable oil temperature readings.

[0044] FIGS. 9A-9H illustrate example flow paths of fluid throughout the pump unit 400 of FIG. 4 according to some embodiments of the present disclosure. In FIG. 9A, the oil is pumped in through the meshed screen 700 at the input section 405, up through the motor 410, and out through the outlet 412. In FIG. 9B, the oil is pumped in through the meshed screen 700 at the input section 405 and through the shaft 403. The oil then flows around the inverter 401, back through the motor and gearbox, into the motor 410 and out the outlet 412. In FIG. 9C, a zoomed-in view of the PCBA containing the temperature sensor 411 is shown. The oil flows through the notch 802 and around to the other side of the PCBA, contacting the temperature sensor 411. In FIG. 9D, the oil is pumped through the mesh screen 700 of the input section 405, around the outside of the housing (e.g., housing 408) and into the section containing the inverter 401. The oil then flows back through the motor and gearbox, into and through the motor 410, and out the outlet 412 and into the section containing inverter 401. FIG. 9E illustrates guiding flow channels for the PCBA, such that the oil contacts the temperature sensor 411. In some embodiments, as shown in FIG. 9F, oil flows from four different directions into the motor 410 during operation. In FIG. 9G, a double gerotor assembly including motors 410 and 600 is shown. The oil is pumped in through the meshed screen 700 at the input section 405 and into the first motor 410 to a common outlet. Moreover, oil is also pumped into the section 402 containing the motor and gearbox, which flows into the section contacting the inverter 401 and back through the section 402. Finally, that oil flows up through the second motor 600 and out the common outlet along with the oil from the first gerotor 410. In FIG. 9H, oil comes in through a first inlet at the input section 405, through a meshed screen 700, and into the shaft 403. In addition, oil comes in through a second inlet (e.g., with another meshed screen) at the top of the pump unit 400. Finally, oil can exit the pump unit 400 at a common outlet 412.

[0045] FIG. 10 is an exploded view of a single gerotor electric oil pump system 1000 for use within the electric pump system within an electric drive unit according to some embodiments of the present disclosure. The system 1000 can include a meshed screen 1001, O-rings 1002, an inlet 1003, an outer gerotor 1004, an inner gerotor 1005, a pump housing 1006, a rotor assembly 1007, a stator assembly 1008, an IDC plate 1009, a PCBA 1010, an O-ring 1011, and an ECU cover 1012.

[0046] FIG. 11 is an exploded view of a dual gerotor electric oil pump system 1100 for use within the electric pump system within an electric drive unit according to some embodiments of the present disclosure. The system 1100 can include a primary inlet meshed screen 1101, O-rings 1102, an inlet 1103, a primary inlet outer gerotor 1104, a primary inlet inner gerotor 1105, a sandwich plate 1106, a dowel pin 1107, a secondary inlet outer gerotor 1108, a secondary inlet inner gerotor 1109, a pump housing 1110, a secondary inlet screen 1111, a rotor assembly 1112, a stator assembly 1113, an IDC plate 1114, a PCBA 1115, an O-ring 1116, an X-ring 1117, and an ECU cover 1118.

[0047] FIG. 12 is an example method 1200 for operating the pump unit of FIG. 4 according to some embodiments of the present disclosure. At block 1201, oil is stored in a sump. In some embodiments, the sump can be either a wet sump or a dry sump, depending on the type of vehicle. In some embodiments, in a wet sump architecture, oil can be pulled through a single suction point or inlet (e.g., inlet 405). In some embodiments, in a dry sump architecture, oil can be pulled in via dual independent oil inlets in the pump 400. At block 1202, the pump 400 pulls oils from the sump into itself (i.e., oil is pulled into the pump, see FIGS. 9A-9H for various flow paths of the oil). At block 1203, the pump inverter (e.g., inverter 401) is submerged in the oil, thereby cooling the inverter 401 during operation. At block 1204, an oil temperature sensor (e.g., oil temperature sensor 411 of FIG. 4) measures one or more temperatures values of the oil. In some embodiments, the oil temperature sensor, as discussed above, is contained within the electric oil pump 400 and can reside on a PCBA near the inverter 401 such that it is submerged in oil during operation. Because of the nature of operation of such a device, where oil is constantly being circulated around the cavities to maintain lubrication and cooling capabilities, the steps may not necessarily be performed in order and often may be performed simultaneously or approximately simultaneously. At block 1205, the pump 400 pumps oil to other vehicle components, such as bearings, rotors, stators, and gears of a motor (e.g., a traction motor), as well as other potential places within an electric vehicle. In wet sump architectures, the oil can drain back to and accumulate in the wet sump.

[0048] FIG. 13 shows a drive unit 1300 with a submerged inverter according to some embodiments of the present disclosure. Consistent with other embodiments described herein, the drive unit 1300 includes a sump 1301, an oil pump 1302, a filter 1303, a heat exchanger 1304, a gearbox 1305, a motor 1306, and an inverter 1307. The oil pump 1302 pumps the oil, enabling both lubrication and cooling of the gearbox 1305, motor 1306, and the inverter 1307.

[0049] FIGS. 14A-14D show various drive units with submerged inverters according to some embodiments of the present disclosure. FIG. 14A shows a drive unit with submerged inverter that utilizes a wet sump and a dual gerotor configuration. FIG. 14B shows a drive unit with submerged inverter that utilizes a wet sump and a single gerotor configuration. FIG. 14C shows a drive unit with submerged inverter that utilizes a dry sump and a dual gerotor configuration. FIG. 14D shows a drive unit with submerged inverter that utilizes a dry sump and a single gerotor configuration.

[0050] While various embodiments have been described above, it should be understood that they have been presented by way of example and not limitation. It will be apparent to persons skilled in the relevant art(s) that various changes in form and detail may be made therein without departing from the spirit and scope. In fact, after reading the above description, it will be apparent to one skilled in the relevant art(s) how to implement alternative embodiments. For example, other steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Accordingly, other implementations are within the scope of the following claims.

[0051] In addition, it should be understood that any figures which highlight the functionality and advantages are presented for example purposes only. The disclosed methodology and system are each sufficiently flexible and configurable such that they may be utilized in ways other than that shown.

[0052] Although the term “at least one” may often be used in the specification, claims and drawings, the terms “a”, “an”, “the”, “said”, etc. also signify “at least one” or “the at least one” in the specification, claims and drawings.

[0053] Finally, it is the applicant's intent that only claims that include the express language "means for" or "step for" be interpreted under 35 U.S.C.

112(f). Claims that do not expressly include the phrase "means for" or "step for" are not to be interpreted under 35 U.S.C. 112(f).

Claims

1. An electric pump unit comprising: an electric motor assembly; an inverter coupled to the motor assembly; an inverter; at least one inlet; and an outlet; wherein the electric pump unit is configured to: pump in oil from a sump through the at least one inlet and a gerotor assembly; cool the inverter by submerging the inverter in oil; and pump the oil to at least one vehicle system external to the electric pump unit.

2. The electric pump unit of claim 1, wherein the sump is a dry sump.

3. The electric pump unit of claim 2, wherein the at least one inlet comprises two independent inlets.

4. The electric pump unit of claim 3, wherein pumping in the oil from the sump comprises pumping in the oil through both independent inlets.

5. The electric pump unit of claim 4, wherein the pump comprises two gerotors to pump the oil.

6. The electric pump unit of claim 1, wherein the sump is a wet sump.

7. The electric pump unit of claim 1, wherein the gerotor assembly pressurizes the oil prior to the cooling of the inverter.

8. The electric pump unit of claim 1, wherein the pump comprises a printed circuit board assembly (PCBA), the PCBA comprising at least one temperature sensor configured to measure temperature values of the oil.

9. The electric pump unit of claim 8, wherein the at least one temperature sensor resides at a lowest point of the PCBA.

10. The electric pump unit of claim 8, wherein the PCBA comprises a channel at least partially surrounding the at least one temperature sensor.

11. The electric pump unit of claim 8, wherein the PCB A resides in a position that submerges the at least one temperature sensor in the oil.

12. The electric pump unit of claim 8, wherein the PCBA is conformally coated.

13. The electric pump unit of claim 10, wherein the oil flows through the channel.

14. The electric pump unit of claim 8 comprising an electronic control unit (ECU) configured to control the pump.

15. The electric pump unit of claim 14, wherein the ECU receives the measured temperature values from the at least one temperature sensor and controls the electric pump unit based on the received measured temperature values.

16. The electric pump unit of claim 14, wherein the ECU is configured to cause the pump to maintain a consistent oil level of the oil.

17. A method for operating an electric pump unit comprising a gearbox and electric motor assembly and an inverted couple thereto, the method comprising: storing oil in a sump; pumping, via the electric pump unit, the oil from the sump through at least one inlet and a gerotor assembly; cooling the inverter by submerging the inverter in the oil; and pumping, via the electric pump unit, of the oil to at least one vehicle system external to the electric pump unit.

18. The method of claim 17 comprising measuring a temperature of the oil with at least one temperature sensor embedded in a printed circuit board assembly (PCBA) contained in the electric pump unit.

19. The method of claim 18 comprising controlling the pump based on the measured temperature of the oil.

20. The method of claim 18, wherein the at least one temperature sensor resides at a lowest point of the PCBA.