drive system and vehicle

Abstract

The invention relates to a Drive system (1) for providing variable system power (P), in particular in a motor vehicle or rail vehicle, comprising a first electric motor (10), a second electric motor (20) and a coupling module (3) for coupling the first electric motor (10) with the second electric motor (20), wherein the coupling module (3) has a first module input (31), a second module input (32) and a module output (33), wherein the first electric motor (10) has a first power (P1) and a first rotor position sensor (12) and is permanently connected to the first module input (31), wherein the second electric motor (20) has a second power (P2) and no rotor position sensor and can be disconnected from and connected to the second module input (32) by means of a decoupling unit (22), wherein in a coupling mode of the drive system (1) the first electric motor (10) has a first rotational speed which is preferably identical to a second rotational speed of the second electric motor (20), wherein the system power (P) is the sum of the first power (P1) and the second power (P2), and wherein the system power (P) is available at the module output (33).

Description

[0001] The invention relates to a drive system for providing variable system power, particularly in a motor vehicle or rail vehicle, comprising a first electric motor, a second electric motor, and a coupling module for coupling the first electric motor to the second electric motor. The invention further relates to a vehicle, particularly a motor vehicle or rail vehicle, with such a drive system and a transmission.

[0002] Electric drive systems are the subject of intensive research in the context of the mobility transition and can be used to power vehicles, such as trucks. Electric drive systems can consist of one or more electric motors, particularly two. Calculations show that drive systems with two electric motors offer advantages in terms of efficiency, especially compared to drive systems with one electric motor. For example, two small electric motors can provide the same power as one larger electric motor.A drive system with a larger electric motor must remain operational at all times to provide drive energy, whereas in a drive system with two smaller electric motors, one of the motors can be switched off or disconnected – at least temporarily, for example, when the vehicle's energy demand is low – thus saving energy. However, the efficiency advantages of drive systems with two electric motors also come with disadvantages, such as higher costs, which are incurred particularly for the second electric motor and a more complex control unit.

[0003] Against this background, the task is to provide an optimized drive system with multiple electric motors.

[0004] This task is solved by a drive system for providing variable system power, particularly in a motor vehicle or rail vehicle, comprising a first electric motor, a second electric motor and a coupling module for coupling the first electric motor to the second electric motor. wherein the coupling module has a first module input, a second module input and a module output, wherein the first electric motor has a first power output and a first rotor position sensor and is permanently connected to the first module input, wherein the second electric motor has a second power output and no rotor position sensor and can be disconnected from and connected to the second module input by means of a decoupling unit, wherein in a coupling mode of the drive system the first electric motor has a first speed which is preferably identical to a second speed of the second electric motor, where the system power is the sum of the first power and the second power, and the system power is available at the module output.

[0005] The drive system according to the invention can provide variable system power, particularly in a motor vehicle or rail vehicle. This allows for advantageous energy savings, especially during periods of lower drive power demand. The drive system comprises a first electric motor, a second electric motor, and a coupling module. The coupling module allows the first and second electric motors to be mechanically coupled advantageously and in a compact design. The coupling module has a first module input, a second module input, and a module output. The first electric motor has a first power output and a first rotor position sensor and is permanently connected to the first module input. The second electric motor has a second power output and no rotor position sensor and is disconnected by means of a decoupling unit.The second electric motor (decoupling unit DCU) can be disconnected from and connected to the second module input. Variable system power can be provided by decoupling the second electric motor from the coupling module or from the first electric motor. Furthermore, the fact that the second electric motor does not have a rotor position sensor offers the advantage of reduced manufacturing costs for the drive system. Additionally, no mounting bracket or wiring is required on the second electric motor for the installation and operation of a separate rotor position sensor. Moreover, no evaluation unit for a second rotor position sensor is necessary, or the drive system's evaluation unit can be configured more simply, since it only needs to process signals from the first rotor position sensor located on the first electric motor.The drive system can be operated in a separation mode and in a coupling mode. In the coupling mode of the drive system, the first electric motor has a first speed that is preferably identical to a second speed of the second electric motor. In other words, the gear ratio between the first and second electric motors can be one. The system power is the sum of the first and second power outputs, and this system power is available at the module output.

[0006] For the control and / or regulation of such a drive system with two electric motors, it may be necessary to know the respective rotor position of both motors. Determining the second rotor position of the second motor can advantageously be carried out in coupled mode based on, or starting from, the first rotor position of the first motor, which can be easily determined using the first rotor position sensor. Since the two motors can have the same rotational speed, particularly in coupled mode, the first rotor position can correlate with the second. In other words, initial angular information from the first motor can be used to determine the second angular information from the second motor without requiring an additional or second rotor position sensor.For example, to determine the second rotor position based on the first rotor position, one or more correction calculations can be performed, whereby the correction calculations can take into account elasticities in the drive system, particularly in the coupling module. Furthermore, correction calculations can consider clearances in the form of gap dimensions or play in the drive system, particularly in the coupling module. In other words, it can be taken into account that a first rotor of the first electric motor is rotatable by a certain amount relative to a stationary second rotor of the second electric motor. A correction calculation can, in particular, be a simple addition or subtraction. The clearance in the coupling or in the coupling module can constitute the main component of any misalignment between the two electric motors or their respective rotors.Furthermore, the play and / or offset angle between the two electric motors can be determined individually for each system before commissioning the drive system - following production - and permanently stored in the control unit for further use.

[0007] According to a preferred embodiment of the invention, the first and second electric motors are identical. Because the two electric motors are identical, manufacturing can be simpler and, due to higher production volumes, more cost-effective. In particular, the first power output of the first electric motor can be equal to the second power output of the second electric motor. By adding the second electric motor or by coupling the second electric motor with the first electric motor, the system power can be increased, in particular doubled. Increasing the system power is particularly advantageous for starting on an incline, i.e., when driving uphill, and especially when the vehicle is heavily loaded, for example, a truck.

[0008] In a preferred embodiment of the invention, the coupling module is designed as a gear drive with a first gear, a second gear, and an intermediate gear, wherein the first gear is connected to the first electric motor, the second gear is connectable to the second electric motor, and the intermediate gear is connected to the module output. The first gear and the second gear are preferably identical. A gear drive allows for the simple and advantageous integration of multiple (mechanical) power sources. The coupling module is preferably designed as a spur gear drive, wherein the first gear, the second gear, and the intermediate gear preferably each have helical teeth. The first gear and the second gear preferably have identical dimensions, thus easily achieving a gear ratio of one.For example, the first gear and the second gear have the same pitch circle diameter. The first power can be transmitted to the intermediate gear via the first gear, and the second power via the second gear. At the module output, where a shaft connected to the intermediate gear, in particular a drive shaft of the drive system, can be located, the system power can be provided as the cumulative power from the first and second power sources. In other words, the module output can simultaneously function as a system output. For sufficient strength, the intermediate gear can be dimensioned larger than the first and second gears. For example, the intermediate gear can have a larger pitch circle diameter than the first and / or second gear. These larger dimensions allow for the transmission of sufficiently high torques and system power.Similarly, for sufficient strength, the drive shaft of the drive system, i.e., the shaft connected to the intermediate gear, can be dimensioned larger, in particular having a larger diameter, than shafts connected to the first and second gears respectively.

[0009] A preferred embodiment of the invention provides that the first electric motor has several first coupling positions and the second electric motor has several second coupling positions, wherein a first number of first coupling positions and a second number of second coupling positions are limited, and coupling of the first electric motor to the second electric motor can be achieved by any combination of a first coupling position with any second coupling position. Preferably, the first number of first coupling positions and the second number of second coupling positions are identical or the same, for example, three, four, five, six, seven, eight, nine, or ten each. Due to the multitude of coupling possibilities, the first and the second electric motors can be advantageously connected or coupled to each other in different configurations or angular positions of the respective rotors.

[0010] According to an advantageous embodiment of the invention, the first electric motor and the second electric motor have the same number of pole pairs, wherein the first number of first coupling positions and the second number of second coupling positions are equal to the number of pole pairs. Since individual poles and pole pairs of an electric machine are arranged in fixed positions, in particular in fixed positions within a stator, a first and / or second coupling position can be defined based on the arrangement or the respective positions of the pole pairs. The first and the second electric motor are preferably each designed as synchronous machines in which the respective rotor rotates synchronously with the rotating magnetic field of the associated stator.

[0011] In an alternative embodiment of the invention, it is conceivable that the first electric motor has a first number of first pole pairs, wherein the second electric motor has a second number of second pole pairs, which is not equal to the first number.

[0012] A preferred embodiment of the invention provides that the first and second coupling positions can be specified in rotational angles and are each distributed over 360°, wherein the first and second coupling positions are spaced evenly apart by first and second distances, the first distances being equal to the second distances. Because the first and second coupling positions are spaced evenly apart by first and second distances, it is advantageously possible for the electrical angles of the two electric motors in coupling mode to always have a constant offset. This angular offset can be selected by design or construction such that the vibration behavior in the narrower sense and the NVH behavior in the broader sense are optimized. Due to the constant angular offset between the two coupled electric motors, the position or...The angular position of the second electric motor or the second rotor can be advantageously determined using the signals from the first rotor position sensor.

[0013] According to a preferred embodiment of the invention, the first rotor position sensor is arranged between the first electric motor and the coupling module, while the decoupling unit, preferably designed as a jaw coupling, is arranged between the second electric motor and the coupling module. This arrangement allows for a compact design of the drive system.

[0014] In an advantageous embodiment of the invention, the first module input and the second module input are arranged on a first side of the coupling module, with the module output being arranged on a second side of the coupling module, which faces away from the first side of the coupling module. The coupling module can be arranged in a separately designed coupling housing and / or together with the first and second electric motors in a system housing. The coupling housing can have a first housing wall in which the first module input and the second module input are formed or arranged. Similarly, the coupling housing can have a second housing wall that is arranged parallel to the first housing wall, with the module output being formed or arranged in the second housing wall.

[0015] A further aspect of the invention is a vehicle, in particular a motor vehicle or rail vehicle, comprising a drive system according to one of the preceding embodiments and a transmission. For the transmission of system power, the module output of the coupling module or the system output of the drive system can be connected to an input side of the transmission. By appropriately configuring the transmission, propulsion power can be provided at an output side of the transmission, which can be transmitted to the corresponding propulsion elements, in particular wheels, of the vehicle. Furthermore, the advantages and technical effects explained in the description of the drive system according to the invention and its embodiments, individually or in combination, also apply to the vehicle.

[0016] Further details and advantages of the invention will be explained below with reference to the exemplary embodiment shown in the drawings. This shows: Fig. 1 schematically an embodiment of a drive system according to the invention in a truck; and Fig. 2 schematically a moment-dependent angular offset between a first electric motor and a second electric motor of the in the Fig. 1 of the drive system shown.

[0017] In the Fig. Figure 1 schematically illustrates an embodiment of a drive system 1 according to the invention in a truck 100. The drive system 1 provides a variable system power P and comprises a first electric motor 10, a second electric motor 20, and a coupling module 3 for coupling the first electric motor 10 with the second electric motor 20. The coupling module 3 has a first module input 31, a second module input 32, and a module output 33. Furthermore, the first electric motor 10 has a first power output P1 and a first rotor position sensor 12 and is permanently connected to the first module input 31. The second electric motor 20 has a second power output P2 and no rotor position sensor and can be disconnected from and reconnected to the second module input 32 by means of a decoupling unit 22 designed as a claw coupling. In a coupling mode of the drive system 1, in which the drive system 1 is in the Fig. As shown in Figure 1, the first electric motor 10 has a first rotational speed that is identical to a second rotational speed of the second electric motor 20. The system power P is the sum of the first power P1 and the second power P2, and the system power P is available at the module output 33.

[0018] The first power output P1 of the first electric motor 10 and the second power output P2 of the second electric motor 20 can each be understood as the maximum power outputs of the respective electric motors 10 and 20, which are designed as synchronous machines. The first electric motor 10 and the second electric motor 20 are identical in design, i.e., they have, in particular, the same power outputs P1 and P2 and the same number of pole pairs. The first power output P1, the second power output P2, and the system power P are in the Fig. 1 schematically represented as arrows, where the system power P is illustrated with a longer arrow to show that it is composed cumulatively or additively of the first power P1 and the second power P2.

[0019] The coupling module 3 is designed as a spur gear drive with a first gear Z1, a second gear Z2, and an intermediate gear ZZ. The first gear Z1 is connected to the first electric motor 10. The second gear Z2 can be connected to the second electric motor 20. The intermediate gear ZZ is connected to the module output 33. The first gear Z1 and the second gear Z2 are identical. Any energy and / or power losses in the drive system 1 are omitted for the sake of simplicity and illustration. Fig. 1 is disregarded, so that, for example, the second power P2 provided by the second electric motor 20 is not shown at the immediate output of the second electric motor 20, but rather between the decoupling unit 22 and the second gear Z2. In other words, losses in the decoupling unit 22 are disregarded. The system power P is provided at a system output, which may be identical to the module output 33, to a gearbox 50 of the truck 100. A propulsive power P is supplied at an output of the gearbox 50. V provided, which is transmitted to the wheels of the truck 100. Ignoring losses in the gearbox 50, the propulsive power P corresponds to V System performance P.

[0020] According to the invention, signals generated by the first rotor position sensor 12 and transmitted to a [missing information] in the Fig. One control unit (not shown) of the truck 100 is provided for the control and / or regulation of both electric motors 10, 20. In other words, no second / additional rotor position sensor is required for the control and / or regulation of the second electric motor 20. This allows the drive system 1 and its operation to be advantageously simplified and thus optimized.

[0021] The two electric motors 10 and 20 can be coupled in different configurations. For this purpose, the first electric motor 10 has four first coupling positions, and the second electric motor 20 also has four second coupling positions. The coupling of the first electric motor 10 with the second electric motor 20 can be achieved by any combination of one of the four first coupling positions with any of the four second coupling positions. Due to clearances and elasticities / stiffnesses in the drive system 1, particularly in the coupling module 3, a first rotor of the first electric motor 10 can be moved / rotated relative to a stationary second rotor of the second electric motor 20. Therefore, for precise control of the second electric motor 20, it is necessary to determine a second angular position of the second rotor based on a first angular position of the first rotor.However, due to play and elasticity in the drive system, correction calculations must be performed to calculate the second angular position from the first. For this purpose, depending on the exact coupling configuration of the two electric motors 10, 20, an offset Δ between the two rotors must be determined and stored in the control unit. In addition, a play W can be... φThe values ​​between the two electric motors 10, 20 and their respective rotors can be determined, particularly in the new state of the drive system 1, i.e., immediately after completion of its production. Furthermore, models required for correction calculations—for example, a mathematical relationship between a torque prevailing in the coupling module 3 and the resulting deformations of the gears Z1, ZZ, Z2—can also be stored in the control unit. Important quantities and relationships for such correction calculations are illustrated below. Fig. 2 described.

[0022] In Fig. Figure 2 schematically represents a moment-dependent angular offset W between the first electric motor 10 and the second electric motor 20 of the system described in the diagram. Fig.The drive system 1 is shown in Figure 1. Since the current angular offset W is in particular a function of the currently transmitted torque M, it can therefore also be denoted as W(M). The torque can in particular be that which is transmitted by an output shaft of the drive system 1, where the output shaft of the drive system 1 is the shaft connected to the intermediate gear ZZ. The offset Δ between the rotors of the two electric motors 10, 20, set or configured after the production of the drive system 1 – for example, 90° – can be stored in the control unit. Due to a backlash W φThe actual angular offset W between the two electric motors 10 and 20, which arises primarily from backlash or total backlash between the gears Z1, ZZ, and Z2, can be W1 during operation. However, due to a relatively high torque M and the associated deformation of the gears Z1, ZZ, and Z2, the actual angular offset W can also be W2. In other words, the offset between the electric motors 10 and 20 can increase or decrease depending on the transmitted torque M. Reference symbol list 1 Drive system 3 coupling module 10 First electric motor 12 First rotor position sensor 20 Second electric motor 22 Decoupling unit 31 First module input 32 Second module input 33 Module output 50 manual transmission 100 vehicles, trucks M torque P System performance P1 First Performance P2 Second Power P V Thrusting power W Angle offset W φ Game Z1 First gear Z2 Second gear ZZ intermediate gear Δ Offset

Claims

Drive system (1) for providing variable system power (P), in particular in a motor vehicle or rail vehicle, comprising a first electric motor (10), a second electric motor (20) and a coupling module (3) for coupling the first electric motor (10) to the second electric motor (20), wherein the coupling module (3) has a first module input (31), a second module input (32) and a module output (33), wherein the first electric motor (10) has a first power (P1) and a first rotor position sensor (12) and is permanently connected to the first module input (31), wherein the second electric motor (20) has a second power (P2) and no rotor position sensor and can be disconnected from and connected to the second module input (32) by means of a decoupling unit (22), wherein in a coupling mode of the drive system (1) the first electric motor (10) has a first rotational speed,which is preferably identical to a second speed of the second electric motor (20), wherein the system power (P) is additively composed of the first power (P1) and the second power (P2), wherein the system power (P) is available at the module output (33). Drive system (1) according to claim 1, characterized in that the first electric motor (10) and the second electric motor (20) are identical. Drive system (1) according to claim 1 or 2, characterized in that the coupling module (3) is designed as a gear transmission with a first gear (Z1), a second gear (Z2) and an intermediate gear (ZZ), wherein the first gear (Z1) is connected to the first electric motor (10), wherein the second gear (Z2) is connectable to the second electric motor (20), wherein the intermediate gear (ZZ) is connected to the module output (33), wherein the first gear (Z1) and the second gear (Z2) are preferably identical. Drive system (1) according to one of the preceding claims, characterized in that the first electric motor (10) has several first coupling positions and the second electric motor (20) has several second coupling positions, wherein a first number of first coupling positions and a second number of second coupling positions are limited, wherein coupling of the first electric motor (10) with the second electric motor (20) can be realized by any combination of a first coupling position with any second coupling position. Drive system (1) according to claim 4, characterized in that the first electric motor (10) and the second electric motor (20) have the same number of pole pairs, wherein the first number of first coupling positions and the second number of second coupling positions are equal to the number of pole pairs. Drive system (1) according to one of claims 5 or 6, characterized in that the first coupling positions and the second coupling positions can be specified in rotation angles and are each distributed over 360°, wherein the first coupling positions and the second coupling positions are spaced evenly apart by first distances and second distances, wherein the first distances are equal to the second distances. Drive system (1) according to one of the preceding claims, characterized in that the first rotor position sensor (12) is arranged between the first electric motor (10) and the coupling module (3), wherein the decoupling unit (22), which is preferably designed as a claw coupling, is arranged between the second electric motor (20) and the coupling module (3). Drive system (1) according to one of the preceding claims, characterized in that the first module input (31) and the second module input (32) are arranged on a first side of the coupling module (3), wherein the module output (33) is arranged on a second side of the coupling module (3) which is facing away from the first side of the coupling module (3). Vehicle (100), in particular a motor vehicle or rail vehicle, comprising a drive system (1) according to one of the preceding claims and a transmission (50).

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