DE102021210628A1 - Electric drive system with controllable cooling system, motor vehicle and method - Google Patents

Abstract

The present invention relates to an electric drive system (1) for a motor vehicle (2), having a plurality of electronic modules (3), an electric motor (4) and a cooling system (5) for cooling the electronic modules (3) and the electric motor (4). , wherein the electronic modules (3) have a first electronic module (3a) and a second electronic module (3b), wherein the cooling system (5) has a main cooling fluid line (6) for conducting a fluid flow of a cooling fluid and a cooling fluid pump (7) for conveying of the cooling fluid. The cooling system (5) has a first bypass line (6a) for conducting a first partial fluid stream of the cooling fluid to cool the first electronic module (3a), the first bypass line (6a) being connected to the main cooling fluid line (6 ) is coupled for fluid communication in such a way that the first valve (8a) can be used to control a size of the first partial fluid flow conducted from the main cooling fluid line (6) into the first bypass line (6a), and wherein the cooling system (5) has a control device (9) for controlling of the first valve (8a). The invention also relates to a motor vehicle (2) and a method for operating an electric drive system (1).

Description

The present invention relates to an electric drive system with a controllable cooling system for a motor vehicle. Furthermore, the invention relates to a motor vehicle with a generic electric drive system and a method for operating a generic electric drive system.

Electric drive systems are known which have an electric motor, a transmission and a number of electronic modules, such as charging electronics, a direct-current converter, a traction network distributor and a pulse-controlled inverter. During operation, heat is lost from the individual components of the electric drive system, which can lead to overheating of the respective component. For example, overheating can bring about a reduction in efficiency, accelerate wear of the respective component, or directly and permanently damage the respective component. In order to avoid overheating of the components, known drive systems therefore have cooling systems.

It is known, for example, to cool the components using cooling circuits. Electric motors have, for example, a motor housing with a cooling jacket through which a cooling fluid, such as a water-glycol mixture, can be passed for heat dissipation. The power electronics are arranged in a separate electronics housing, which can be cooled by means of the cooling fluid via additional cooling fluid lines. In alternative embodiments, the power electronics are integrated into the motor housing. The cooling device is designed to first cool the motor housing in the area of the power electronics and then in the area of the electric motor by means of the cooling fluid. In particular, cooling hoses and plug-in tube elements are used to provide a cooling fluid circuit required for this.

From the document CN 207 518 441 U an electric drive system is known which has an electric motor with a water-cooled housing. Electronic modules of the electric drive system are arranged on a side of the water-cooled housing facing away from the electric motor. The document CN 109 050 226 B discloses an electric drive system having an electric motor with a water-cooled first housing. A water-cooled second housing is fastened to the first housing, in which electronic modules of the electric drive system are arranged. In order to form a common cooling fluid circuit, the first housing has a first hose connection and the second housing has a second hose connection for coupling to a common connecting hose. From the document DE 10 2013 226 804 B4 an electric drive system is known in which, to form a common cooling fluid circuit, cooling fluid lines of a motor housing are coupled in fluid communication via plug connections with cooling fluid lines of component housings of electronic components.

Known electric drive systems often have the disadvantage that they are not very compact and require a relatively large amount of space and have a relatively large overall weight. Furthermore, known electrical drive systems often have the disadvantage that cooling of the individual components cannot be provided as required, so that the efficiency of the cooling system is reduced. Finally, known electric drive systems often have a relatively low degree of pre-assembly, so that final assembly of the electric drive system is very complex and time-consuming due to the large number of individual components to be assembled and coupled with one another in fluid communication.

It is therefore the object of the present invention to eliminate or at least partially eliminate the disadvantages described above in an electric drive system. In particular, it is the object of the present invention to create an electric drive system, a motor vehicle and a method for operating an electric drive system of a motor vehicle which ensure needs-based and efficient cooling of the components of the electric drive system in a simple and cost-effective manner and preferably have a particularly compact structure.

The above object is solved by the patent claims. Accordingly, the object is achieved by an electric drive system for a motor vehicle with the features of independent claim 1, by a motor vehicle with the features of independent claim 9 and by a method for operating an electric drive system of a motor vehicle with the features of independent claim 10. Further features and details of the invention result from the dependent claims, the description and the drawings. Features and details that are described in connection with the electric drive system according to the invention naturally also apply in connection with the motor vehicle according to the invention and the method according to the invention and in each case vice versa, so that with regard to the disclosure of the individual aspects of the invention, mutual reference is or can always be made.

According to a first aspect of the invention, the object is achieved by an electric drive system for a motor vehicle. The electric drive system has several electronic modules, an electric motor and a cooling system for cooling the electronic modules and the electric motor. The electronic modules have a first electronic module and a second electronic module. The cooling system has a main cooling fluid line for conducting a fluid flow of a cooling fluid and a cooling fluid pump for conveying the cooling fluid. According to the invention, the cooling system has a first bypass line for conducting a first partial fluid stream of the cooling fluid to cool the first electronic module, the first bypass line being coupled in fluid communication via a controllable first valve to the main cooling fluid line in such a way that a size of the main cooling fluid line is determined by means of the first valve guided into the first bypass line first partial fluid flow is controllable. Furthermore, the electric drive system has a control device for controlling the first valve.

The electric drive system has several electronic modules. The electric drive system thus has at least the first electronic module and the second electronic module. According to the invention, an electronic module can be designed, for example, as a direct-current converter, traction network distributor, pulse-controlled inverter, charging device or the like. According to the invention, an electronic module can also be designed as a combination of several electronic modules, such as a direct-current converter with a pulse-controlled inverter, a direct-current converter with a charger, a direct-current converter with a pulse-controlled inverter and a charger or the like. The electric drive system preferably has a traction battery, in particular a high-voltage battery. According to the invention, the electric drive system can be designed for use in an electric vehicle, hybrid vehicle, such as a plug-in hybrid vehicle, a fuel cell vehicle or the like.

The electric motor has a stator and a rotor which is mounted so as to be rotatable about a rotor longitudinal axis with respect to the stator. According to the invention, the electric motor can be designed, for example, as a synchronous motor or an asynchronous motor. At least one of the electronic modules is preferably designed to operate the electric motor, for example to selectively supply current to a stator winding of the stator and/or a rotor winding of the rotor. The electric drive system preferably has a gearbox which is coupled to the rotor of the electric motor. The transmission is preferably designed to step down a motor speed of the electric motor at a transmission input of the transmission to an output speed at a transmission output of the transmission. The transmission is preferably arranged with the electric motor in a common motor housing.

The cooling system is designed to cool the electronic modules and the electric motor. The cooling system is preferably designed to cool the transmission. The cooling system has the main cooling fluid line for conducting the fluid flow of the cooling fluid, such as an oil, a water-glycol mixture or the like. Furthermore, the cooling system has the cooling fluid pump for delivering the cooling fluid. The cooling fluid pump can be operated, for example, via a gear wheel of the transmission directly via the electric motor and/or via its own electric pump motor. Operation via the gearbox or the electric motor has the advantage that fewer components are required and the electric drive system can therefore be constructed in a particularly compact manner. A separate pump motor has the advantage that the components can be cooled even when the electric drive system is at a standstill. The control device is preferably designed and set up to control the pump motor.

The main cooling fluid line is designed to supply the cooling fluid to the electric motor, for example into a cooling jacket of the electric motor, a stator cooling duct, a rotor cooling duct or the like. The first bypass line branches off from the main cooling fluid line and is coupled in fluid communication with the main cooling fluid line via the first valve. Cooling fluid for cooling the first electronic module, for example for cooling a first housing of the first electronic module, can be branched off from the main cooling fluid line via the first bypass line. Within the scope of the invention, a bypass line is understood to mean a fluid line by means of which only a partial fluid flow of the fluid flow of the main fluid line can be branched off. The fluid flow is thus always larger than the partial fluid flow, such as the first partial fluid flow. The area of the cooling system for cooling the first electronic module is also referred to as the first heat exchanger within the scope of the invention. The first bypass line is preferably routed into a second main fluid line on a side of the first heat exchanger opposite the main fluid line. The cooling fluid circuit of the cooling system can be closed via the second main fluid line.

The cooling system has the first valve for controlling the first partial fluid flow. The first valve is preferably adjustable between an open position, in which the first partial fluid flow is maximized, and a closed position, in which the first partial fluid flow is interrupted. Accordingly, the first valve is preferably designed to release the first bypass line in the open position in such a way that the first partial fluid flow is maximized at a constant pump capacity of the cooling fluid pump and to close the first bypass line in the closed position. The first valve preferably has a plurality of partial opening positions, so that the size of the first partial fluid flow can be adjusted via the first valve. The partially open positions are preferably arranged between the open position and the closed position.

The control device is designed to control the first valve. The control device is preferably designed to control the electric motor. The control device is preferably designed as an electronic module of the electric drive system. The control device is preferably designed to control the first valve depending on an operating state of the electric drive system. An operating state of the electric drive system is understood within the scope of the invention as operating conditions such as operating temperature, torque or the like, and operating modes such as driving mode, charging mode, parking mode or the like. For example, a rotor temperature, stator temperature, transmission temperature, temperature of an electronic module, temperature of the cooling fluid at various points in the cooling fluid circuit or the like can be relevant as the operating temperature. In order to determine the operating temperatures, the electric drive system preferably has a number of temperature sensors. In the driving mode, for example, a distinction can be made between electric driving and recuperation. In the context of the invention, a charging mode is understood to mean, for example, charging an energy store of the electric drive system via an external charging device, such as a charging station.

The control device is preferably designed to determine a cooling requirement for the first electronic module on the basis of the operating state of the electric drive system and to control the cooling of the first electronic module as required by actuating the first valve, so that at least overheating of the first electronic module and/or an unnecessary or excessive cooling of the first electronic module is avoided and/or improved efficiency of the first electronic module is provided.

An electric drive system according to the invention for a motor vehicle has the advantage over conventional electric drive systems that needs-based cooling of the components of the electric drive system, such as the electric motor, a transmission or the electronic components, can be improved with simple means and in a cost-effective manner. Targeted cooling of the first electronic module via the first bypass line can be improved by the first valve. Greater cooling of the first electronic module can be achieved by increasing the first partial fluid flow. By reducing the first partial fluid flow, a cooling capacity for cooling the additional components of the electric drive system, such as the electric motor and the additional electronic modules, can be increased. In addition, the electric drive system can be implemented in a particularly compact manner thanks to a common cooling fluid circuit.

According to a preferred further development of the invention, it can be provided in an electric drive system that the first electronic module is in the form of charging electronics or has charging electronics. The charging electronics are preferably designed to charge an energy store of the electric drive system with electrical energy from an external charging device, such as a charging station. More preferably, the charging electronics are designed to charge the energy store with electrical energy recuperated by the electric motor. In some operating states of the electric drive system, such as a parking mode or driving mode, the charging electronics require little or no cooling. In other operating states, such as when charging the energy store, the charging electronics generate more heat and therefore have a greater need for cooling. This has the advantage that needs-based cooling of the charging electronics is improved with simple means and in a cost-effective manner.

It is preferred according to the invention that the cooling fluid is designed as a ferrofluid, the cooling fluid pump having a cooling fluid pump line arranged on the electric motor in such a way that the cooling fluid can be pumped through the magnetic field of the electric motor during operation of the electric motor. The cooling fluid pump line is preferably arranged on the stator of the electric motor or is integrated in a motor housing of the electric motor. This has the advantage that with simple means and in a cost-effective manner, a particularly compact Cooling fluid pump is provided. In addition, it is ensured in this way that a flow of coolant always flows during operation of the electric motor.

More preferably, the cooling fluid pump is designed and set up to change a conveying direction of the cooling fluid. In this way, a cooling sequence in which the components of the electric drive system can be cooled can be reversed. For this purpose, the cooling fluid pump preferably has a pump motor with a variable direction of rotation. This has the advantage that needs-based cooling of the components of the electric drive system is improved with simple means and in a cost-effective manner.

In a particularly preferred embodiment of the invention, the electric drive system has a third electronic module, the main cooling fluid line for cooling the second electronic module being routed to the second electronic module and for cooling the third electronic module being routed from the second electronic module to the third electronic module. This means, for example, guiding the electronic modules into a housing, a housing section, a cooling jacket or the like. In this preferred configuration, the second electronic module, the third electronic module and the electric motor are arranged in a row as part of the cooling system, so that in one flow direction the cooling fluid of the main cooling fluid line first cools the second electronic module, then the third electronic module and finally the electric motor . This has the advantage that the electric drive system has a particularly compact structure and is easy to assemble using simple means and in a cost-effective manner.

Preferably, the electric drive system has a third electronic module, wherein the cooling system has a second bypass line for conducting a second partial fluid flow of the cooling fluid to cool the second electronic module, wherein the second bypass line is coupled to the main cooling fluid line via a controllable second valve in such a fluid-communicating manner that a size of the second partial fluid flow conducted from the main cooling fluid line into the second bypass line can be controlled by means of the second valve. More preferably, the cooling system has a third bypass line for conducting a third partial fluid flow of the cooling fluid to cool the third electronic module, wherein the third bypass line is coupled in fluid communication via a controllable third valve to the main cooling fluid line such that the third valve is used to Main cooling fluid line directed into the third bypass line third partial fluid stream is controllable. The control device is designed and set up to control the second valve and the third valve. The second valve and/or third valve can preferably be adjusted between an open position, in which the respective partial fluid flow is maximized, and a closed position, in which the respective partial fluid flow is interrupted. Accordingly, the second valve or third valve is preferably designed to release the respective bypass line in the open position in such a way that the respective partial fluid flow is maximized at a constant pump capacity of the cooling fluid pump and to close the respective bypass line in the closed position. The second valve and/or third valve preferably has a plurality of partial opening positions, so that the size of the respective partial fluid flow can be adjusted via the respective valve. The partially open positions are preferably arranged between the open position and the closed position. The control device is preferably designed and set up to control the second valve and/or the third valve depending on an operating state of the electric drive system. The control device is preferably designed to determine a cooling requirement for the second electronic module and/or the third electronic module based on the operating state of the electric drive system and to cool the second electronic module or the third electronic module by actuating the second valve or the third valve To control the module as required, so that at least overheating of the respective electronic module and/or unnecessary or excessive cooling of the respective electronic module is avoided and/or improved efficiency of the respective electronic module is provided. This has the advantage that needs-based cooling of the electronic modules is improved with simple means and in a cost-effective manner.

According to a preferred embodiment of the invention, the cooling system has a fourth bypass line for conducting a fourth partial fluid flow of the cooling fluid to cool the electric motor, wherein the fourth bypass line is fluidly coupled to the main cooling fluid line via a controllable fourth valve in such a way that a size of the the fourth partial fluid flow directed from the main cooling fluid line into the fourth bypass line can be controlled, and wherein the control device is designed and set up to control the fourth valve. The fourth valve is preferably adjustable between an open position, in which the fourth partial fluid flow is maximized, and a closed position, in which the fourth partial fluid flow is interrupted. Accordingly, the fourth valve is preferably designed to release the fourth bypass line in the open position in such a way that the fourth partial fluid flow is maximized with a constant pump capacity of the cooling fluid pump and to close the fourth bypass line in the closed position. The fourth valve preferably has a plurality of partial opening positions, so that the size of the fourth partial fluid flow can be adjusted via the fourth valve. The partially open positions are preferably arranged between the open position and the closed position. The control device is preferably designed and set up to control the fourth valve depending on an operating state of the electric drive system. The control device is preferably designed to determine a cooling requirement for the electric motor on the basis of the operating state of the electric drive system and to control the cooling of the electric motor as required by actuating the fourth valve, so that at least overheating of the electric motor and/or unnecessary or excessive cooling of the electric motor is prevented avoided and / or an improved efficiency of the electric motor is provided. According to the invention, the fourth bypass line can be provided for cooling any transmission. Alternatively, according to the invention, a fifth bypass line with a fifth valve can be provided for this purpose, which are preferably designed analogously to the fourth bypass line and the fourth valve. This has the advantage that needs-based cooling of the electric motor is improved with simple means and in a cost-effective manner.

The electronic modules, the electric motor and the transmission are particularly preferably arranged within a common drive system housing. The main cooling fluid line is preferably arranged at least partially on the drive system housing or is formed in a wall of the drive system housing. This has the advantage that the electric drive system can be preassembled as a compact assembly using simple means and in a cost-effective manner and can be easily integrated in a motor vehicle in final assembly.

According to a second aspect of the invention, the object is achieved by a motor vehicle with an electric drive system. According to the invention, the electric drive system is designed as an electric drive system according to the invention. Accordingly, the electric drive system has a number of electronic modules, an electric motor and a cooling system for cooling the electronic modules and the electric motor. The electronic modules have a first electronic module and a second electronic module. The cooling system has a main cooling fluid line for conducting a fluid flow of a cooling fluid and a cooling fluid pump for conveying the cooling fluid. The cooling system has a first bypass line for conducting a first partial fluid stream of the cooling fluid to cool the first electronic module, the first bypass line being coupled in fluid communication via a controllable first valve to the main cooling fluid line in such a way that the first valve is used to determine a size of the flow from the main cooling fluid line to the first partial fluid flow conducted through the first bypass line can be controlled. In addition, the electric drive system has a control device for controlling the first valve.

All the advantages that have already been described for an electric drive system according to the first aspect of the invention result from the motor vehicle according to the invention. Accordingly, the motor vehicle according to the invention has the advantage over conventional motor vehicles that needs-based cooling of the components of the electric drive system, such as the electric motor, a transmission or the electronic components, can be improved with simple means and in a cost-effective manner. Targeted cooling of the first electronic module via the first bypass line can be improved by the first valve. Greater cooling of the first electronic module can be achieved by increasing the first partial fluid flow. By reducing the first partial fluid flow, a cooling capacity for cooling the additional components of the electric drive system, such as the electric motor and the additional electronic modules, can be increased. In addition, the electric drive system can be implemented in a particularly compact manner thanks to a common cooling fluid circuit.

• - Fördern des Kühlfluids durch die Hauptkühlfluidleitung mittels der Kühlfluidpumpe zum Kühlen der elektronischen Module sowie des Elektromotors,
• - Erfassen eines Betriebszustands des elektrischen Antriebssystems mittels der Steuerungsvorrichtung,
• - Ermitteln eines ersten Kühlbedarfs des ersten elektronischen Moduls mittels der Steuerungsvorrichtung, und
• - Gezieltes Betätigen des ersten Ventils mittels der Steuerungsvorrichtung zum Abzweigen des ersten Fluidstroms in die erste Bypassleitung in Abhängigkeit des ermittelten ersten Kühlbedarfs.

According to a third aspect of the invention, the object is achieved by a method for operating an electric drive system according to the invention for a motor vehicle. The procedure has the following steps:

• - Conveying the cooling fluid through the main cooling fluid line by means of the cooling fluid pump for cooling the electronic modules and the electric motor,
• - detecting an operating state of the electric drive system by means of the control device,
• - determining a first cooling requirement of the first electronic module by means of the control device, and
• - Targeted actuation of the first valve by means of the control device for branching off the first fluid flow into the first bypass line as a function of the determined first cooling requirement.

Preferably, as part of the method, a second cooling requirement of the second electron ic module and / or a third cooling requirement of a third electronic module and / or a fourth cooling requirement of the electric motor determined by the control device. The targeted actuation of the first valve preferably also takes place as a function of the ascertained second cooling requirement and/or the ascertained third cooling requirement and/or the ascertained fourth cooling requirement. If a second valve and/or a third valve and/or a fourth valve is present, the respective valve is actuated preferably taking into account the respective cooling requirement and more preferably additionally taking into account one or more of the other cooling requirements. It can thus be ensured that when a component of the electronic drive system has a particularly high cooling requirement, sufficient cooling capacity is provided and is not consumed by the other components. The control device is preferably designed and set up to take into account a predetermined prioritization of the cooling requirements when controlling the valves.

All the advantages that have already been described for an electric drive system according to the first aspect of the invention and for a motor vehicle according to the second aspect of the invention result from the method according to the invention. Accordingly, the method according to the invention has the advantage over conventional methods that needs-based cooling of the components of the electric drive system, such as the electric motor, a transmission or the electronic components, is improved with simple means and in a cost-effective manner. Targeted actuation of the first valve improves targeted cooling of the first electronic module via the first bypass line. Greater cooling of the first electronic module can be achieved by increasing the first partial fluid flow. By reducing the first partial fluid flow, a cooling capacity for cooling the additional components of the electric drive system, such as the electric motor and the additional electronic modules, can be increased.

• 1 in einer Prinzipskizze ein elektrisches Antriebssystem gemäß einer bevorzugten ersten Ausführungsform,
• 2 in einer Prinzipskizze ein elektrisches Antriebssystem gemäß einer bevorzugten zweiten Ausführungsform,
• 3 in einer Prinzipskizze ein elektrisches Antriebssystem gemäß einer bevorzugten dritten Ausführungsform,
• 4 in einer Prinzipskizze ein elektrisches Antriebssystem gemäß einer bevorzugten vierten Ausführungsform,
• 5 in einer Prinzipskizze ein elektrisches Antriebssystem gemäß einer bevorzugten fünften Ausführungsform,
• 6 in einer Seitenansicht eine bevorzugte Ausführungsform eines erfindungsgemäßen Kraftfahrzeugs, und
• 7 in einem Ablaufplan eine bevorzugte Ausführungsform eines erfindungsgemäßen Verfahrens.

An electric drive system according to the invention, a motor vehicle according to the invention and a method according to the invention are explained in more detail below with reference to drawings. They each show schematically:

• 1 in a schematic diagram, an electric drive system according to a preferred first embodiment,
• 2 in a schematic diagram, an electric drive system according to a preferred second embodiment,
• 3 in a schematic diagram, an electric drive system according to a preferred third embodiment,
• 4 in a schematic diagram, an electric drive system according to a preferred fourth embodiment,
• 5 in a schematic diagram, an electric drive system according to a preferred fifth embodiment,
• 6 in a side view a preferred embodiment of a motor vehicle according to the invention, and
• 7 in a flowchart a preferred embodiment of a method according to the invention.

Elements with the same function and mode of action are in the 1 until 7 each provided with the same reference numerals.

In 1 an electric drive system 1 according to a preferred first embodiment of the invention is shown schematically in a basic sketch. The electric drive system 1 has a number of electronic modules 3 and an electric motor 4 . It can be provided according to the invention that a gear, not shown, is arranged on the electric motor 4 . Of the electronic modules 3, an electronic module 3 is designed as a first electronic module 3a, an electronic module 3 as a second electronic module 3b, an electronic module 3 as a third electronic module 3c and an electronic module 3 as a fourth electronic module 3d. The first electronic module 3a is preferably in the form of charging electronics or has charging electronics. More preferably, the first electronic module 3a has a DC converter. Alternatively, the DC converter can also be formed in a fourth electronic module (not shown). The second electronic module 3b is preferably designed as a traction network distributor or has a traction network distributor. The third electronic module 3c is preferably designed as a pulse-controlled inverter or has a pulse-controlled inverter.

The electric drive system 1 has a cooling system 5 for cooling the electronic modules 3 and the electric motor 4 . The cooling system 5 is preferably also designed to cool an optional transmission (not shown) of the electric drive system 1 . The cooling system 5 has a main cooling fluid line 6, which is connected to a cooling fluid pump 7 for conveying a cooling fluid, a cooling area of the second electronic module 3b, a cooling area of the third electronic module 3c, a cooling area of the electric motor Tors 4 and remaining components 13 of the cooling system 5, such as a refrigerant-coolant heat exchanger, a coolant reservoir or the like, forms a closed cooling fluid circuit. A first valve 8a for metering a first partial fluid flow of the cooling fluid from the main cooling fluid line 6 into a first bypass line 6a is arranged on the main cooling fluid line 6 . The first bypass line 6a is routed to the first electronic module 3a for cooling the first electronic module 3a.

The electric drive system 1 has a control device 9 for controlling the first valve 8a. Furthermore, the electric drive system 1 has a first temperature sensor 12a arranged on the first electronic module 3a for measuring a first temperature of the first electronic module 3a, a second temperature sensor 12b arranged on the second electronic module 3b for measuring a second temperature of the second electronic module 3b, an am third temperature sensor 12c arranged on the third electronic module 3c for measuring a third temperature of the third electronic module 3c and a fourth temperature sensor 12d arranged on the electric motor 4 for measuring a fourth temperature of the electric motor 4 . The first temperature sensor 12a, the second temperature sensor 12b, the third temperature sensor 12c and the fourth temperature sensor 12d are coupled to the control device 9 in a data-communicating manner. The control device 9 is thus able to control the first valve 8a as required. Furthermore, the electric drive system 1 has a drive system housing 11 in which the components of the electric drive system 1, in particular the electronic modules 3, the electric motor 4, the cooling system 5 and the control device 9, are arranged.

2 shows an electric drive system 1 according to a preferred second embodiment of the invention schematically in a basic sketch. The preferred second embodiment of the invention differs from that in 1 illustrated first embodiment of the invention in an embodiment of the cooling system 5 for cooling the second electronic module 3b. The main cooling fluid line 6 forms the closed cooling fluid circuit together with the cooling fluid pump 7, the cooling area of the third electronic module 3c, the cooling area of the electric motor 4 and the remaining components 13 of the cooling system 5. A second valve 8b for metering a second partial fluid flow of the cooling fluid from the main cooling fluid line 6 into a second bypass line 6b is also arranged on the main cooling fluid line 6 . The second bypass line 6b is routed to the second electronic module 3b for cooling the second electronic module 3b. The control device 9 is designed to control the first valve 8a and the second valve 8b.

In 3 an electric drive system 1 according to a preferred third embodiment of the invention is shown schematically in a basic sketch. The preferred third embodiment of the invention differs from that in 2 illustrated second embodiment of the invention in an embodiment of the cooling system 5 for cooling the third electronic module 3c. The main cooling fluid line 6 forms the closed cooling fluid circuit together with the cooling fluid pump 7, the cooling area of the electric motor 4 and the remaining components 13 of the cooling system 5. A third valve 8c for metering a third partial fluid flow of the cooling fluid from the main cooling fluid line 6 into a third bypass line 6c is also arranged on the main cooling fluid line 6 . The third bypass line 6c is routed to the third electronic module 3c for cooling the third electronic module 3c. The control device 9 is designed to control the first valve 8a, the second valve 8b and the third valve 8c.

4 shows an electric drive system 1 according to a preferred fourth embodiment of the invention schematically in a basic sketch. The preferred fourth embodiment of the invention differs from that in 3 illustrated third embodiment of the invention in an embodiment of the cooling system 5 for cooling the electric motor 4. The main cooling fluid line 6 forms the closed cooling fluid circuit together with the cooling fluid pump 7 and the remaining components 13 of the cooling system 5. A fourth valve 8d for metering a fourth partial fluid flow of the cooling fluid from the main cooling fluid line 6 into a fourth bypass line 6d is also arranged on the main cooling fluid line 6 . The fourth bypass line 6d is routed to the electric motor 4 for cooling the electric motor 4 . The control device 9 is designed to control the first valve 8a, the second valve 8b, the third valve 8c and the fourth valve 8d.

In 5 an electric drive system 1 according to a preferred fifth embodiment of the invention is shown schematically in a basic sketch. The preferred fifth embodiment of the invention differs from that in 1 illustrated first embodiment of the invention in an embodiment of the cooling fluid pump 7 of the cooling system 5. The cooling fluid pump 7 has a cooling fluid pump line 10 arranged on the electric motor 4. In addition, the cooling fluid is designed as a ferrofluid. The cooling fluid can be conveyed through the magnetic field of the electric motor 4 .

6 shows a preferred embodiment of a motor vehicle 2 according to the invention schematically in a side view. The motor vehicle 2 has an electric drive system 1 according to the invention with a high-voltage battery 14 for supplying the electric motor 4 with electric energy. In this exemplary embodiment, the electric motor 4 is arranged in a front area of the motor vehicle 2 . According to a preferred alternative embodiment of the invention, the electric motor 4 can also be arranged in a rear area or a central area of the motor vehicle 2 . According to the invention, the electric drive system 1 can also have several electric motors 4 .

In 7 a preferred embodiment of a method according to the invention is shown schematically in a flowchart. In a first method step 100, the cooling fluid is conveyed through the main cooling fluid line 6 by means of the cooling fluid pump 7 for cooling the electronic modules 3 and the electric motor 4 . The cooling fluid pump 7 is preferably controlled by the control device 9 . In a second method step 200, an operating state of the electric drive system 1 is determined using the control device 9 . Here, control device 9 preferably evaluates a first temperature of the first electronic module 3a determined by a first temperature sensor 12a and/or a second temperature of the second electronic module 3b determined by a second temperature sensor 12b and/or a third temperature of the electronic module 3b determined by a third temperature sensor 12c third electronic module 3c and/or a fourth temperature of electric motor 4 determined by a fourth temperature sensor 12d. More preferably, the control device 9 evaluates an operating mode of the motor vehicle 2, such as energizing the electric motor 4, a current generated by the electric motor 4, a charging current for charging the high-voltage battery 14 or the like.

In a third method step 300, a first cooling requirement of the first electronic module 3a is determined by means of the control device 9 as a function of the detected operating state, in particular the first temperature and an expected heat development of the first electronic module 3a in the current or future operating mode. In a fourth method step 400, the first valve 8a is actuated in a targeted manner by means of the control device 9 for branching off the first fluid flow from the main fluid line 6 into the first bypass line 6a depending on the determined first cooling requirement. The actuation of the first valve 8a preferably takes place as part of a regulation, so that the individual method steps are preferably carried out repeatedly.

reference list

1

electric drive system

2

motor vehicle

3

electronic module

3a

first electronic module

3b

second electronic module

3c

third electronic module

3d

fourth electronic module

4

electric motor

5

cooling system

6

main cooling fluid line

6a

first bypass line

6b

second bypass line

6c

third bypass line

6d

fourth bypass line

7

cooling fluid pump

8a

first valve

8b

second valve

8c

third valve

8d

fourth valve

9

control device

10

cooling fluid pump line

11

drive system housing

12a

first temperature sensor

12b

second temperature sensor

12c

third temperature sensor

12d

fourth temperature sensor

13

remaining components

14

high-voltage battery

100

first step in the process

200

second process step

300

third step

400

fourth step

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• CN 207518441 U [0004]
• CN 109050226B [0004]
• DE 102013226804 B4 [0004]

Claims (10)

Electrical drive system (1) for a motor vehicle (2), having a plurality of electronic modules (3), an electric motor (4) and a cooling system (5) for cooling the electronic modules (3) and the electric motor (4), the electronic modules (3) have a first electronic module (3a) and a second electronic module (3b), the cooling system (5) having a main cooling fluid line (6) for conducting a fluid flow of a cooling fluid and a cooling fluid pump (7) for conveying the cooling fluid, characterized in that characterized in that the cooling system (5) has a first bypass line (6a) for conducting a first partial flow of the cooling fluid to cool the first electronic module (3a), the first bypass line (6a) being connected to the main cooling fluid line via a controllable first valve (8a). (6) is coupled in such a fluid-communicating manner that by means of the first valve (8a) a size of the main cooling fluid line (6) in the first bypass line (6a) passed ers th partial fluid flow is controllable, and wherein the electric drive system (1) has a control device (9) for controlling the first valve (8a). Electric drive system (1) according to claim 1 , characterized in that the first electronic module (3a) is designed as charging electronics or has charging electronics. Electric drive system (1) according to claim 1 or 2 , characterized in that the cooling fluid is designed as a ferrofluid, the cooling fluid pump (7) having a cooling fluid pump line (10) arranged on the electric motor (4) in such a way that the cooling fluid is driven by the magnetic field of the electric motor (4) during operation of the electric motor (4). is fundable. Electrical drive system (1) according to one of the preceding claims, characterized in that the cooling fluid pump (7) is designed and set up to change a conveying direction of the cooling fluid. Electrical drive system (1) according to one of the preceding claims, characterized in that the electrical drive system (1) has a third electronic module (3c), the main cooling fluid line (6) for cooling the second electronic module (3b) leading to the second electronic module ( 3b) and for cooling the third electronic module (3c) from the second electronic module (3b) to the third electronic module (3c). Electric drive system (1) according to a Claims 1 until 4 , characterized in that the electric drive system (1) has a third electronic module (3c), the cooling system (5) for conducting a second partial fluid flow of the cooling fluid for cooling the second electronic module (3b) having a second bypass line (6b), wherein the second bypass line (6b) is coupled via a controllable second valve (8b) to the main cooling fluid line (6) in such a fluid-communicating manner that, by means of the second valve (8b), a size of the flow from the main cooling fluid line (6) into the second bypass line (6b) guided second partial fluid stream is controllable, wherein the cooling system (5) has a third bypass line (6c) for conducting a third partial fluid stream of the cooling fluid for cooling the third electronic module (3c), wherein the third bypass line (3c) via a controllable third valve (8c ) is coupled to the main cooling fluid line (6) in such a fluid-communicating manner that by means of the third valve (8c) a size of the the third partial fluid stream conducted from the main cooling fluid line (6) into the third bypass line (6c) can be controlled, and wherein the control device (9) is designed and set up to control the second valve (8b) and the third valve (8c). Electric drive system (1) according to claim 6 , characterized in that the cooling system (5) has a fourth bypass line (6d) for conducting a fourth partial fluid stream of the cooling fluid for cooling the electric motor (4), the fourth bypass line (6d) being connected to the main cooling fluid line via a controllable fourth valve (8d). (6) is coupled for fluid communication in such a way that the fourth valve (8d) can be used to control a size of the fourth partial fluid flow routed from the main cooling fluid line (6) into the fourth bypass line (6d), and wherein the control device (9) is designed and set up, to control the fourth valve (8d). Electrical drive system (1) according to one of the preceding claims, characterized in that the electronic modules (3) and the electric motor (4) are arranged within a common drive system housing (11). Motor vehicle (2) with an electric drive system (1), characterized in that the electric drive system (1) is designed as an electric drive system (1) according to one of the preceding claims. Method for operating an electric drive system (1) for a motor vehicle (2) according to one of Claims 1 until 8th , Having the following steps: - Conveying the cooling fluid through the main cooling fluid line (6) by means of the cooling fluid pump (7) for cooling the electronic modules (3) and the electric motor tor (4), - detecting an operating state of the electric drive system (1) by means of the control device (9), - determining a first cooling requirement of the first electronic module (3a) by means of the control device (9), and - targeted actuation of the first valve (8a ) by means of the control device (9) for branching off the first fluid flow into the first bypass line (6a) depending on the determined first cooling requirement.

Images