Method for heating vehicle components

Abstract

A method for heating components of a vehicle (4), wherein the vehicle (4) comprises a first electric drive unit (1.1) and a second electric drive unit (1.2), wherein the first electric drive unit (1.1) generates a first torque (M1) and wherein the second electric drive unit (1.2) generates a second torque (M2), wherein the sum of the first torque (M1) and the second torque (M2) is a driving torque (M3), wherein the vehicle (4) includes an inverter system (2.1, 2.2) for supplying the electric drive units (1.1, 1.2) with alternating current (I). 1.2) is characterized in that, within the framework of the method for generating a desired driving torque (M3), the first electric drive unit (1.1) is operated as a generator and the second electric drive unit (1.2) is operated as a motor such that a total current flow in the inverter system (2.1, 2.2) is generated which is greater than a total current flow which would be generated in the inverter system (2.1, 2.2) in a case in which both electric drive units (1.1, 1.2) are operated as motors to generate the desired driving torque (M3).

Description

Technical field

[0001] The invention relates to a method for heating components of a vehicle according to the preamble of claim 1. The invention further relates to a system, a vehicle, a computer program and a computer-readable medium according to the dependent claims. State of the art

[0002] At low temperatures, the viscosity of oil is very low, which may prevent sufficient oil supply to vehicle components in such situations. Particularly in electric vehicles, excessively low temperatures can also reduce the efficiency of components such as inverters and batteries.

[0003] Furthermore, batteries often have limited energy storage capacity at cold temperatures, which can negatively impact regenerative braking and switching processes (especially synchronization in vehicles with switchable electric drives). Therefore, it is crucial that various components and the oil in electric vehicles reach their operating temperature quickly.

[0004] Existing solutions for rapidly increasing component and oil temperatures in electric vehicles have various drawbacks. For example, they do not yet function satisfactorily in terms of the speed of temperature increase or in terms of energy efficiency. General description of the invention

[0005] The object of the invention is to eliminate or at least reduce the disadvantages of the prior art.

[0006] The problem is solved by a method for heating components of a vehicle, wherein the vehicle comprises a first electric drive unit and a second electric drive unit, wherein the first electric drive unit generates a first torque, wherein the second electric drive unit generates a second torque, wherein the sum of the first torque and the second torque is a driving torque, wherein the vehicle comprises an inverter system for supplying the electric drive units with alternating current, wherein, within the framework of the method for generating a desired driving torque, the first electric drive unit is operated as a generator and the second electric drive unit is operated as a motor such that a total current flow is generated in the inverter system which is greater than a total current flow which would be generated in the inverter system in one case.in which both electric drive units are motor-driven to generate the desired driving torque.

[0007] The electric drive units can each be, for example, an electric motor, in particular an AC motor, in particular a three-phase motor, or each of the electric drive units can, for example, comprise such an electric motor.

[0008] The problem is solved by such a method because the larger current flow, especially in the inverter system, which results from the fact that not both drive units are operated as motors, but rather one of the two electric drive units is operated as a generator (in other words, braking), causes the components of the vehicle's drive system, and especially the inverters in the inverter system, to heat up faster than in cases where both electric drive units would operate exclusively as motors to generate the desired driving torque.These larger current flows lead to higher heat losses in the components involved, such as inverters, electric drive units, batteries, cables, and the like, which then also causes the oil surrounding these components to heat up faster than in cases where the total current flow in the inverter system is smaller.

[0009] In advantageous embodiments, the inverter system comprises a first inverter for supplying the first electric drive unit with alternating current and a second inverter for supplying the second electric drive unit with alternating current, wherein the first inverter generates a direct current output and provides this direct current output to the second inverter as its direct input. Such a configuration has the advantage that the alternating current generated by the generator operation of the first electric drive unit and fed into the first inverter additionally heats this inverter.Furthermore, this design has the advantage that, because the direct current generated by the first inverter from the alternating current supplied by the first electric drive unit is fed back into the second inverter, particularly good energy efficiency of the overall system is achieved. This is especially true compared to alternative designs where the first inverter would feed its generated direct current back into a battery, which would result in battery charging losses. Thus, this specific embodiment creates a synergy effect: the larger overall current flow through the inverter system allows for faster heating of components, and the direct feeding of generator-generated direct current from the first inverter back into the second inverter results in particularly good energy efficiency.

[0010] In advantageous embodiments, the second inverter is provided with a battery input current in addition to the inverter's own DC input current. This battery input current is typically provided by one or more batteries in the vehicle.

[0011] In advantageous embodiments, the vehicle comprises two batteries, the inverter system comprising two inverters, each of the two inverters being electrically connected exclusively to one of the two batteries, so that each inverter has its own battery, each of the two inverters being electrically connected exclusively to one of the two electric drive units, so that each inverter has its own electric drive unit, the inverter whose electric drive unit operates as a generator feeding a direct current into its battery, and the inverter whose electric drive unit operates as a motor receiving a direct current from its battery.The term "exclusively electrically connected" means that direct currents can flow between the respective inverter and the respective battery, or between the respective inverter and the respective electric drive unit. Indirect connections, for example via the vehicle body, are therefore not considered "exclusively electrically connected".

[0012] In advantageous embodiments, the process determines, preferably continuously, which of the two batteries receives current and which receives current. This determination is based on the respective charge levels and / or temperatures of the two batteries. In other words, the process typically determines continuously and repeatedly which of the two electric drive units should be the first (generator-operating) drive unit and which should be the second (motor-operating) drive unit. Depending on the current charge levels of the batteries, the drive unit connected to the less charged battery via its inverter can then operate as a generator until the charge levels of the batteries are equalized.The other electric drive unit can then operate as a generator, and so on. In this way, the charge levels of both batteries can always be kept at a similar level.

[0013] In advantageous embodiments, each electric drive unit comprises a plurality of electric motors, wherein the electric motors of each drive unit are either all driven, all regenerated, or partially driven and partially regenerated. Such a configuration of the method enables a particularly flexible application of the method.

[0014] In advantageous embodiments, the inverter system comprises more than two inverters, wherein at least one inverter receives a direct current from at least one battery and / or a direct current from at least one other inverter, and wherein at least one inverter receives a direct current into at least one battery and / or at least one other inverter. The concepts described above are also applicable to cases in which the inverter system comprises more than two inverters, for example, three, four, five, or more inverters. In advantageous embodiments, the method comprises more than two batteries, wherein the charging and discharging concepts described above for up to two batteries are also applicable to cases with more than two batteries.

[0015] The problem is further solved by a system comprising means for at least partial implementation of a method according to at least one of the aforementioned embodiments.

[0016] Such a system typically comprises at least one control unit capable of adjusting the motor operation of one electric drive unit and simultaneously the generator operation of another electric drive unit to achieve a desired driving torque. In typical embodiments, such a system also includes a charge controller component capable of ensuring that the charges of all participating batteries are maintained at a substantially comparable level throughout the process, for example, such that the charges of the individual batteries differ by no more than 20%, preferably no more than 15%, and particularly preferably no more than 10%.

[0017] In advantageous embodiments, the system is suitable for at least partially carrying out, coordinating, and / or controlling a method for heating vehicle components according to at least one of the aforementioned embodiments. For this purpose, the system typically comprises means for carrying out, coordinating, and / or controlling a method according to at least one of the aforementioned embodiments.

[0018] Advantageously, at least some of the aforementioned components are implemented in the system using computer program code. In advantageous embodiments, the system, and in particular at least some of the aforementioned components, is at least partially part of a vehicle control unit and / or a cloud. In typical embodiments, the system is or includes a control unit, in particular a vehicle control unit.

[0019] In one embodiment of the invention, a vehicle is suitable for carrying out a method according to at least one of the aforementioned embodiments and / or comprises a system according to one of the aforementioned embodiments. For this purpose, the vehicle typically includes means for carrying out a method according to at least one of the aforementioned embodiments.

[0020] In one embodiment of the invention, a computer program comprises instructions which, when executed by a computer, cause the computer to perform one of the aforementioned methods. The computer program can also be referred to as a computer program product.

[0021] In one embodiment of the invention, a computer-readable medium comprises computer program code for carrying out one of the aforementioned methods. The term "computer-readable medium" includes, in particular but not exclusively, hard drives and / or servers and / or memory sticks and / or flash memory and / or DVDs and / or Blu-rays and / or CDs. Additionally, the term "computer-readable medium" also includes a data stream, such as that generated when a computer program and / or a computer program product is downloaded from the internet. Brief description of the drawings

[0022] The invention is briefly explained below with reference to drawings, which show: Fig. 1: a first schematic representation of a method according to the invention in the form of a moment diagram, Fig. 2: a schematic representation of a method according to the invention in a first embodiment, as a block diagram, Fig. 3: a schematic representation of a method according to the invention in a second embodiment, as a block diagram, Fig. 4: a schematic representation of a vehicle according to the invention in a first embodiment, and Fig. 5: a schematic representation of a vehicle according to the invention in a second embodiment. Description of preferred embodiments

[0023] Fig. Figure 1 shows a schematic representation of a method according to the invention. In particular, in Fig. Figure 1 shows a method according to the invention in the form of a torque diagram. In the torque diagram, a first torque M1, a second torque M2, and a driving torque M3 are each plotted against time t. The first torque M1 is located in the negative region of the y-axis and is therefore a generator torque. The second torque M2 is located in the positive region of the y-axis and is thus a motor torque. The driving torque M3 is the sum of the first torque M1 and the second torque M2. To generate the second torque M2 in a vehicle, a specific direct current is drawn from a battery (in Fig. 1 (not shown), this direct current is in a Fig. 1. Inverter system (also not shown) converted into alternating current, and this alternating current is used to power a [unclear] inverter system. Fig. 1. A second electric drive unit, also not shown, is operated by a motor to generate the second torque M2 as motor torque. Simultaneously, a [unclear] Fig. The first electric drive unit, also not shown, is used to brake the vehicle, so to speak, by operating as a generator and thus producing the first torque M1 as a generator torque. This generates a direct current, which also powers the... Fig. The current flows through the inverter system (not shown) and is then either fed back into a battery or fed back into the inverter system as direct current. The total current flowing through the inverter system is therefore greater than the total current required to generate the driving torque M3 solely through motor operation. Because a larger total current flows through the system, particularly the inverter system, than in a case where both torques are motor torques, the vehicle components in which this process takes place heat up more quickly. This is partly due to the higher total current, which also results in greater heat losses in the individual components.

[0024] Fig. Figure 2 shows a schematic representation of a method according to the invention in a first embodiment as a block diagram. In particular, in Fig. 2 a first electric drive unit 1.1 is shown, which generates a first torque M1, which is a generator torque. In addition, in Fig. Figure 2 shows a second electric drive unit 1.2, which generates a second torque M2, which is a motor torque. In total, the two electric drive units 1.1 and 1.2 thus generate a driving torque, which is calculated from the sum of the motor torque M2 and the generator torque M1. Fig. Figure 2 also shows a first inverter 2.1 and a second inverter 2.2, both of which are parts of an inverter system. The first inverter 2.1 accepts an alternating current I generated by the first electrical drive unit 1.1. 1.1The second inverter 2.2 outputs an alternating current I that it generates itself. 1.2 from which the second electric drive unit 1.2 receives the second motor torque M2. The first inverter 2.1 generates from the alternating current I supplied to it. 1.1 an output direct current I 2.1 This output direct current I 2.1 is then fed to the second inverter 2.2. Furthermore, in the Fig. In the second inverter 2.2, an additional battery input DC current I3 is provided to the second inverter 2.2. In total, a sum of the output DC current I is thus generated. 2.1 The first inverter and the battery input DC current I3 are fed into the second inverter 2.2. It can therefore be said that Fig. 2. First, it can be seen that a larger total current flows through the inverter system with the first inverter 2.1 and the second inverter 2.2 than in a case where both electric drive units were operated exclusively by motors to generate the desired driving torque. Second, it can be seen that the output DC current I generated by the first inverter 2.1 2.1 The power is fed directly back into the second inverter 2.2, specifically without going through a battery. This eliminates charging and discharging losses with respect to this output DC current I. 2.1 avoid.

[0025] Fig. Figure 3 shows a schematic representation of a method according to the invention in a second embodiment as a block diagram. Fig. Figure 3 again shows an inverter system with a first inverter 2.1 and a second inverter 2.2. Furthermore, a first electric drive unit 1.1 and a second electric drive unit 1.2 are again shown. The first electric drive unit 1.2 generates a first torque M1 (generative), and the second electric drive unit 1.2 generates a second torque M2 (motorized). Accordingly, the second inverter 2.2 supplies the second electric drive unit 1.2 with an alternating current I. 1.2 available. The first electric drive unit 1.1 also feeds the alternating current I it generates into the power supply. 1.1 into the first inverter 2.1. The second inverter 2.2 receives a direct current I. 3.2 from battery 3.2 as battery input DC. Battery 3.2 is in the Fig. In the embodiment shown in section 3, the battery is thus discharged. The first inverter 2.1, however, provides the battery 3.1 with a direct current output I. 2.1 available to charge this battery 3.1. One can therefore imagine that a battery charge of battery 3.2 in the Fig. In the embodiment shown in Figure 3, the charge level of battery 3.1 is greater than that of battery 3.2. Therefore, the method is carried out such that battery 3.1 is charged and battery 3.2 is discharged. If the charge levels of the two batteries 3.1 and 3.2 now equalize, and in particular if the charge of battery 3.1 becomes greater than the charge of battery 3.2, then the method can be modified such that the second electric drive unit 1.2 switches to generator mode and thus charges battery 3.2, while the first electric drive unit 1.1 switches to motor mode and thus discharges battery 3.1. In this way, the charge levels of the two batteries 3.1 and 3.2 would then equalize again.

[0026] Fig. Figure 4 shows a schematic representation of a vehicle 4 according to the invention in a first embodiment. The vehicle 4 comprises a tractor unit 5 and a trailer 6. Furthermore, the vehicle 4 comprises a first electric drive unit 1.1 and a second electric drive unit 1.2. The first electric drive unit 1.1 is operated as a generator (i.e., it brakes the vehicle 4). The second electric drive unit 1.2 is operated as a motor (i.e., it drives the vehicle 4). The electric drive units 1.1, 1.2 can typically comprise one or more electric motors, which are arranged in Fig. However, 4 are not explicitly shown. The electric drive units 1.1, 1.2 are in Fig. 4 is furthermore depicted such that they also each comprise an axle of the tractor unit 5. Furthermore, the vehicle 4, and in particular the tractor unit 5, comprises a battery 3. In addition, the vehicle 4, and in particular the tractor unit 5, comprises a system 7 according to the invention, which is designed such that it, with respect to Fig. can perform the 2 described procedures.

[0027] Fig. Figure 5 now shows a schematic representation of a vehicle 4 according to the invention in a second embodiment. The vehicle 4 again comprises a tractor unit 5, a trailer 6, and a system 7 according to the invention. Furthermore, the system 7 shown in Figure 5 also includes the vehicle 4 in a second embodiment. Fig. The vehicle 4 shown in Figure 5 comprises a first electric drive unit 1.1, which is operated as a generator, and a second electric drive unit 1.2, which is operated as a motor. The trailer includes a battery 3.1 and the tractor unit 5 includes a battery 3.2. Because the first electric drive unit 1.1 is operated as a generator, a direct current is supplied to the battery 3.1, thus charging the battery 3.1, as described in Figure 5. Fig. 3 described. Similarly, a direct current is drawn from battery 3.2 by the motor operation of the second electric drive unit 1.2, as described in relation to Fig. 3 described, whereby battery 3.2 is discharged. The system 7 according to the invention is suitable for a method as described in relation to Fig. 3 described, to carry out and in particular to coordinate the charging and discharging of the batteries 3.1, 3.2.

[0028] The invention is not limited to the exemplary embodiments. Rather, the scope of protection is defined by the patent claims. Reference sign 1.1 First electric drive unit 1.2 second electric drive unit 2.1 First inverter 2.2 second inverter 3, 3.1, 3.2 batteries 4 vehicles 5 tractor 6 trailers 7 System I 1.1 Alternating current generated by the first electric drive unit I 1.2 alternating current drawn from the second electric drive unit I 2.1 Output DC current generated by the first inverter I3, I 3.2 Battery input DC supplied to the second inverter M1 first torque M2 second torque M3 driving torque

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