Battery-saving operation with power splitting

Abstract

A method for load control of a battery in a power-split operation of a hybrid vehicle is provided, which includes adjusting a transfer power from a primary electric machine to the battery, so that the battery is protected from damaging loads during a low-load phase; wherein the battery is configured to provide an input power from the secondary electric machine and to receive the transfer power from the primary electric machine.

Description

[0001] The invention relates to a method, a control system and a hybrid vehicle.

[0002] Hybrid vehicles with all-wheel drive are known in the art. Such vehicles comprise an internal combustion engine and one or more electric motors and / or generators and can be operated in a power-split operating mode. An exemplary embodiment of a corresponding drive device can be found in the document DE 103 39 803 A1. In a power-split operating mode, the internal combustion engine is used to drive a first drive axle or to drive a generator, but simultaneously provides torque for the generation of electrical power by a generator, whereby the generated electrical power is transmitted to an electric motor, which then drives a second drive axle. In such operation, a problem arises when there is a sudden and / or unexpected drop in the power drawn by the electric motor.In this case, the unabsorbed power is absorbed by the battery. If the unabsorbed power exceeds the battery's operating limits, the battery may be damaged. Such a drop in power can occur, for example, when a driver assistance system such as anti-skid control (ASR) intervenes. The intervention of an ASR, which can only be implemented in a drive machine such as an electric motor, is difficult to predict and, in addition, a corresponding message from the ASR can be subject to long signal propagation times, meaning that appropriate countermeasures based on the message are not implemented in time. State-of-the-art solutions for this purpose include switching off the combustion engine, which leads to a sudden loss of power on the axle not subject to intervention.

[0003] The document GB 2594276 describes a method which provides for controlling the power generated by a first electric machine on a first axle based on the power requirement on a second axle.

[0004] Furthermore, the document DE 10 2014 110 860 A1 describes a system and method for increasing the available power, for example in situations with increased power requirements.

[0005] There is a need to provide a method that at least partially overcomes the above-mentioned disadvantages and enables protection of the battery from overloads during interventions of driver assistance systems, thereby avoiding unnecessary power losses.

[0006] This object is achieved by the disclosed method according to claim 1, the disclosed battery load control system according to claim 9 and the disclosed hybrid vehicle according to claim 10.

[0007] Further advantageous embodiments of the invention emerge from the subclaims and the following description of preferred embodiments of the present invention.

[0008] Embodiments of the invention are described by way of example and with reference to the accompanying drawings: Fig. 1 illustrates, by way of example, a drive device of a known hybrid vehicle in the operation of which the method according to the disclosure can be applied; and Fig. 2 schematically shows a first embodiment of the method according to the disclosure; and Fig. Figure 3 shows schematically a first method for adjusting the recording power; and Fig. Figure 4 shows schematically a first method for adjusting the recording power; and Fig. 5 schematically shows a second embodiment of the method according to the disclosure; and Fig. 6 schematically shows a third embodiment of the method according to the disclosure; and Fig. 7 schematically shows a fourth embodiment of the method according to the disclosure; and Fig. 8 schematically shows an embodiment of a battery load control system according to the present disclosure.

[0009] Before a more detailed description of embodiments based on the attached drawings, general comments follow.

[0010] One aspect of the present disclosure is a method for load control of a battery in a power-split operation of a hybrid vehicle, comprising adjusting a transfer power of a primary electric machine to the battery such that the battery is protected from damaging loads during a low-load phase, wherein the battery is configured to provide input power for the secondary electric machine and to receive the transfer power from the primary electric machine.

[0011] A hybrid vehicle in which the disclosed method can be used is a vehicle that provides traction power through at least one internal combustion engine (ICE) and a plurality of electric motors (EMUs). The ICE can be an internal combustion engine, for example, a known gasoline engine or a diesel engine, capable of generating torque by combusting a fuel. An EMU can be referred to as a primary EMU. The EMU can be a known electric motor, a DC motor, a generator, or the like. The vehicle further includes a battery, which can be a known high-voltage battery or a traction battery and is capable of receiving electrical energy from external sources, for example, an EMU or a charging station, storing it, and making it available to other components of the hybrid vehicle as needed.

[0012] The primary ELM is designed to absorb torque generated by the ICE and convert it into electrical power. The primary ELM can also be designed to convert electrical power into traction power. The electrical power generated by the primary ELM or converted from torque can be delivered to the battery. The battery can store the received power and make it available to a secondary ELM when needed, which converts the received power into traction power.

[0013] Optionally, the secondary Elm can be designed to receive the transfer power either from the battery or directly from the primary Elm.

[0014] Power-split operation is operation in which the ICE is used to drive a first drive axle, but simultaneously provides torque to the primary engine, which converts the torque into electrical power. The electrical power is then passed on to the secondary engine, which then drives a second drive axle. The electrical power can be passed on to the secondary engine directly. Alternatively, the electrical power can first be passed on to the battery, which then passes it on to the secondary engine. Alternatively, the electrical power can be passed on to the battery, which simultaneously passes it on to the secondary engine, so that only the difference in power is absorbed by the battery.

[0015] Transfer power is the power that is transferred from the primary ELM to the battery and / or the secondary ELM in power-split operation. Input power is the power absorbed by the secondary ELM and converted into traction power. The input power can be provided at least partially by the battery.

[0016] A low-load phase is an operating phase in which the secondary Elm is unable to absorb the electrical power provided by the primary Elm, particularly suddenly and / or unexpectedly. Such a low-load phase can occur if the secondary Elm is adjusted by external, autonomous intervention so that less power is converted into traction power. Such external, autonomous intervention can occur, for example, if an anti-skid control system requires a lower axle rotation speed. Alternatively, a low-load phase can occur if the secondary Elm is damaged. A low-load phase can therefore occur suddenly and / or unexpectedly. In a suddenly occurring low-load phase, the power no longer absorbed by the secondary Elm must be absorbed by the battery. This can exceed the battery's load limits and damage the battery.Due to long signal propagation times, where the signals could be used to predict a sudden low-load phase, it is difficult in conventional control methods to protect the battery from damage during low-load phases.

[0017] By means of the method according to the disclosure, it is possible to prevent the power absorbed by the battery during a low-load phase from causing damage.

[0018] It should be noted that the method according to the disclosure is intended to be carried out in situations in which low-load phases may occur and not only in low-load phases themselves. Low-load phases may occur, for example, in a power-split operation.

[0019] By adjusting the transfer power as disclosed, signals for predicting low-load phases can be omitted, thus ensuring better protection of the battery.

[0020] There are embodiments in which setting the transfer power comprises limiting the input power to a maximum input power and the maximum input power is a sum of a maximum discharge power of the battery and a maximum transfer power.

[0021] The maximum discharge rate of the battery can be the maximum value of the power at which the battery can be discharged without damage, or the maximum value of the power at which the battery can be discharged during normal operation. The maximum discharge rate can be a value specific to a particular battery, a particular battery type, or a particular battery model. The maximum discharge rate can be determined from information provided by a battery manufacturer.

[0022] The maximum discharge power can optionally also be a current value determined from the battery's operating state. The maximum discharge power is the maximum available power that the battery can provide to the secondary battery. The maximum discharge power can also be a maximum power that is released for the secondary battery and provided by the battery. It can be provided to release a power for the secondary battery that is less than the maximum available power, ensuring that auxiliary loads can be supplied.

[0023] By limiting the maximum input power to the sum of the maximum discharge power and the maximum transfer power, it is ensured that the power absorbed by the battery during a low-load phase corresponds to a maximum of the maximum transfer power. The maximum transfer power can be selected to ensure battery protection.

[0024] There are embodiments in which the maximum transfer power is a maximum charging power of the battery. The maximum charging power of the battery can be a maximum value of the power with which the battery can be charged without being damaged. The maximum charging power can be a value specific to a particular battery, a particular battery type, or a particular battery model. The maximum charging power can be determined from information provided by a battery manufacturer. The maximum charging power can optionally also be an instantaneous value determined from the battery's operating state.

[0025] By limiting the maximum transfer power to the maximum charging power, it can be ensured that, before the onset of a low-load phase, the secondary ELM has the maximum possible input power available at a maximum transfer power. Furthermore, it can be ensured that the ICE and / or the primary ELM can continue to operate without changing operating modes. By avoiding an operating mode change, which could, for example, involve shutting down the ICE and / or the primary ELM, which would result in a power loss on the axle driven by the ICE, unnecessary power loss can be avoided.

[0026] There are embodiments that include measuring a grid voltage by a control unit of the primary electric machine and adjusting the transfer power by adjusting a generator torque of the primary electric machine based on the grid voltage by the control unit of the primary electric machine so that a voltage limit of the battery is not violated.

[0027] The grid voltage can be the voltage at which the transfer power is passed to the battery and / or the secondary elm. During a low-load phase, i.e., a sudden drop in the input power absorbed by the secondary elm, a rise in the grid voltage is to be expected. The grid voltage is a measured value that is available to a control unit through direct measurement by a measuring device and is therefore subject to significantly shorter signal propagation times than information provided by other control units. The occurrence of a low-load phase can be detected by measuring the grid voltage.

[0028] The battery's voltage limit can be a maximum value of the voltage at which the battery can be charged without damage. The voltage limit can be a constant value specific to a particular battery, a particular battery type, or a particular battery model. The voltage limit can be determined, for example, from information provided by a battery manufacturer.

[0029] Due to the direct availability of the mains voltage as a measured value, adjustment based on the mains voltage can be carried out in a targeted manner and quickly enough to avoid damage to the battery during a low-load phase. The mains voltage can also be referred to as high voltage or supply voltage.

[0030] There are embodiments in which the upper voltage limit of the battery is determined by a control unit of the battery and the transfer power is adjusted based on the upper voltage limit of the battery.

[0031] Furthermore, the battery control unit can be a battery control unit. The battery control unit can be configured for autonomous control of the battery 210. The battery control unit can be provided with a sensor arrangement that provides information on the basis of which a current operating state of the respective battery can be determined. The operating state can include current load limits, which can be determined based on environmental information, such as a current battery temperature. The operating state can also include a battery temperature and a current battery charge state. Alternatively, the operating state can include a current charging power, an internal resistance of the battery, and an unloaded battery voltage. Again alternatively, the operating state can include a current battery voltage and a current battery current.The load limits can also depend on the number of cells in the battery, the arrangement of the cells and the cell chemistry.

[0032] Since the operating state of the battery depends on environmental factors that influence the operating limits of the battery, an even more targeted adjustment of the transfer power can be achieved by taking instantaneous factors into account.

[0033] There are embodiments in which adjusting the transfer power comprises a reduction of the generator torque of the primary electric machine when the grid voltage increases.

[0034] Adjusting the transfer power can be achieved, for example, by adjusting the generator torque of the primary generator. A low-load phase can be detected by measuring the rise in the grid voltage.

[0035] There are embodiments in which the input power is adjusted by adjusting a motor torque of the secondary electric machine on the basis of the mains voltage by the control unit of the secondary electric machine, so that a lower voltage limit of the battery is not violated, wherein the lower voltage limit of the battery is determined by a control unit of the battery and the input power is adjusted on the basis of the lower voltage limit of the battery.

[0036] The battery's lower voltage limit may be the minimum voltage at which the battery can be charged without damage. The lower voltage limit may be a value specific to a particular battery, battery type, or battery model. The motor torque can also be called engine torque.

[0037] If the lower voltage limit is violated, this may mean that the power transferred from the battery to the secondary elm is too high. Therefore, if the grid voltage is lower than the current lower voltage limit, the power absorbed by the secondary elm can be reduced to increase the grid voltage. By adjusting the transfer power based on the lower voltage limit, not only during low-load phases, but also based on the upper voltage limit, optimal battery protection can be achieved.

[0038] There are embodiments in which adjusting the input power involves reducing the motor torque of the secondary electric machine when the grid voltage decreases. Adjusting the input power can be achieved, for example, by adjusting the motor torque of the secondary motor.

[0039] There are embodiments in which a battery load control system is provided for carrying out the method according to the disclosure. The battery load control system can be implemented, for example, in a control system or a control unit or a plurality of control units of a vehicle.

[0040] There are embodiments in which a hybrid vehicle comprising the battery load control system according to the disclosure is provided. By using the battery load control system according to the disclosure, a battery of the hybrid vehicle can be protected during power-split operation.

[0041] Returning to the attached figures, Fig. 1 schematically and by way of example, a drive device of a known hybrid vehicle, in the operation of which the method according to the disclosure can be applied. The hybrid vehicle 1 comprises, for example, a primary unit 100 for driving a primary axle 10 and a secondary unit 200 for driving a secondary axle 20. Optionally, a mechanical coupling element 30 can be provided, which enables both axles 10, 20 to be driven in parallel by both units 100, 200. The primary unit 100 comprises an internal combustion engine (ICE) 110, which may comprise an ICE control unit 111, and a primary electric machine (pElm) 120, which may comprise a pElm control unit 121. The secondary unit 200 comprises a battery 210, which may comprise a battery control unit 210, and a secondary electric machine (sElm) 220, which may comprise an sElm control unit.

[0042] The hybrid vehicle also includes a primary electrical connection 300 which enables transmission of electrical power from the primary unit 100 in parallel to the sElm 220 and to the battery 210.

[0043] The division into a primary unit 100 and a secondary unit 200, as in Fig. 1 is for illustrative purposes only and is not to be considered limiting. The disclosed method is suitable for any hybrid vehicle 1 capable of maintaining a power-split operating mode.

[0044] The primary electrical connection 300 can, in particular, enable a transfer of electrical energy from the pElm 120 to the battery 210 and the sElm 220. In a power-split operation, the ICE 110 generates a torque that is transferred to the pElm 120.

[0045] The pElm 120 can operate in a generator mode, in which the pElm 120 generates an electrical power, which can be called generator power, from the torque received from the VKM 110.

[0046] It is obvious to those skilled in the art that the pElm 120 can operate either as a generator or as a motor. In generator mode, the pElm converts torque into electrical power. In motor mode, the pElm 120 converts electrical power into traction power. In power-split mode, the pElm 120 operates as a generator.

[0047] The generator power can be transferred to the battery 210 via the primary electrical connection 300. The battery and the sElm 220 can be connected in parallel to the primary Elm. An optional switching element 302 can be provided, which can be set such that electrical power can optionally be transferred either to the sElm 220, or to the battery 210, or to both the sElm 220 and the battery 210 simultaneously. Electrical power transferred from the primary unit 100 to the secondary unit 200 via the primary electrical connection 300 or by equivalent means can be referred to as transfer power.

[0048] The battery 210 is configured to store the electrical power transferred to it as charge energy. The power transferred from the battery 210 to the sElm 220 can be referred to as input power.

[0049] The sElm 220 can be configured to operate either as a generator or as a motor. Even if the sElm 220 is configured to operate optionally as a generator, it operates as a motor in power-split mode.

[0050] The hybrid vehicle 1 may include a voltage measuring device 301, which measures a voltage of the current transmitted from the pElm 120 to the battery 210 and provides it to the pElm control unit 121. The pElm control unit 121 may include the voltage measuring device 301.

[0051] The ICE control unit 111 can be configured for autonomous control of the ICE 110. Likewise, the pElm control unit 121 can be configured for autonomous control of the pElm 120. In particular, the pElm control unit 121 can be configured for implementing the method according to the disclosure. Furthermore, the battery control unit 211 can be configured for autonomous control of the battery 210. Furthermore, the sElm control unit 221 can be configured for autonomous control of the sElm 220.

[0052] Each of the control units 111, 121, 211, 221 can be provided with a sensor arrangement that provides information on the basis of which a current operating state of the respective unit 110, 120, 210, 220 can be determined. The operating state can include current load limits, which can be determined based on environmental information, such as a current temperature of the respective components 110, 120, 210, 220.

[0053] The hybrid vehicle 1 may comprise a vehicle control unit (not shown), which may alternatively be designed for implementing the method according to the disclosure. Fig. 1, the primary axle 10 is shown as the front axle and the secondary axle 20 as the rear axle. However, the hybrid vehicle 1 can also have a rear axle as the primary axle 10 and a front axle as the secondary axle 20. The hybrid vehicle can also have a larger number of axles, each of which can be considered a primary or secondary axle 10, 20. The hybrid vehicle 1 can also have multiple primary and secondary axles 10, 20. Alternatively, the hybrid vehicle can have multiple sElms 220 on the secondary axle, so that each sElm drives a wheel of the secondary axle.

[0054] Fig. 2 schematically shows a first exemplary embodiment of the method according to the disclosure. The method can be carried out in particular when the hybrid vehicle is in a power-split operating mode, in which power-split operation of the vehicle is desired, but at the same time there is a possibility of a sudden drop in the power consumption by the sElm 220. In particular, the method can be carried out continuously during operation of the hybrid vehicle or can be initiated when the vehicle is started up. A sudden drop in the power consumption by the sElm 220 can occur, for example, when the sElm control unit 221 autonomously intervenes in the control of the sElm 220, for example, within the framework of an anti-skid control system known from the prior art or other driver assistance systems, during which the traction power provided by the sElm 220 is reduced.

[0055] If the hybrid vehicle 1 is in a power-split operating mode, the method according to the disclosure can be applied. At the beginning of the method, the vehicle is in the power-split operating mode. In a setting step S21, a setting is made such that the input power is less than or equal to a sum of a maximum transfer power and a maximum discharge power of the battery 210. According to the disclosure, the charging power can assume any value between the maximum charging power and the maximum discharge power of the battery. In a determination step S22, it is determined whether the power-split operation continues. If the power-split operation continues in S22 ("Yes"), the setting step S21 is repeated.If adjustment step S21 is performed after determination step S22, i.e., for the second time, adjustment step S21 may involve leaving the setting unchanged. If power-split operation is not continued in S22 ("No"), the setting made in S21 is canceled in a cancellation step S23, and the method is terminated. The method can be performed again if power-split operation recurs. However, the method can also be active without restrictions at any operating point of the hybrid system.

[0056] The repetition of steps S21 and S22 can occur in a temporal sequence, so that a repetition occurs within a specified period of time. This temporal sequence can be referred to as a cadence. The cadence can be a fixed or variable period of time. The cadence can correspond to a timing of the vehicle control unit. The cadence value can be selected, for example, within a range of 10 ms to 1 s, although larger or smaller values ​​are possible.

[0057] The power-split operating mode can be initiated, for example, by making a corresponding setting, which is not part of the disclosed method. The setting can be made, for example, by setting a runtime variable of a control program of the vehicle control unit to a corresponding value. The setting can also be made based on detecting a corresponding operating state of the vehicle. After the start of the method, a setting step S21 is performed. In the setting step S21, the transfer power transmitted from the pElm 120 to the battery 210 and the sElm 220 is set, for example, such that the input power corresponds to a maximum value.

[0058] The setting of the maximum input power can be carried out by the pElm control unit 121 controlling the pElm 120 in such a way that a generator torque of the pElm 120 is set such that the power generated by the pElm 120 corresponds at most to a maximum value.

[0059] Alternatively, the setting of the maximum input power can be carried out by the ICE control unit 111 controlling the ICE 110 such that the torque transmitted to the pElm 120 is set such that the power generated by the pElm 120 corresponds to a maximum value.

[0060] In determination step S22, the continued presence of the power-split operating mode is determined. This determination can be made based on the detection of the corresponding value of the runtime variable. The determination can also be made based on the detection of the corresponding operating state of the vehicle. An end to power-split operation can be brought about, for example, by changing the value of the runtime variable through a process not subject to the method or by no longer detecting the detected operating state.

[0061] Fig. 3 schematically shows a limitation of the input power 51 according to an embodiment of the method according to the disclosure. Fig. 3 can be used, for example, in step S21 in Fig. 2 can be applied. The y-axis of the diagram shown shows the electrical power provided by the battery 210. The electrical power can be expressed, for example, in watts. The input power 51 is limited such that the input power 51 corresponds to a sum of the maximum transfer power 50 and the maximum discharge power 52 of the battery.

[0062] The maximum discharge rate of the battery 210 is a maximum value of the power at which the battery 210 can be discharged without being damaged, or a maximum value of the power at which the battery 210 can be discharged during normal operation. The maximum discharge rate may be a value specific to a particular battery, a particular battery type, or a particular battery model. The maximum discharge rate may be determined from information provided by a battery manufacturer.

[0063] The maximum discharge power can optionally also be a current value determined from the operating state of the battery. The maximum discharge power can be determined by the battery control unit 211 if the installed battery control unit 211 provides this functionality. The battery control unit 211 can take into account any influences on the maximum discharge power from secondary consumers, such as a heater, interior lighting, or similar consumers.

[0064] Setting the maximum input power 51 can be done as described above with reference to Fig. 2, can be carried out by the pElm control unit 121 controlling the pElm 120 in such a way that a generator torque of the pElm 120 is set such that the transfer power 50 generated by the pElm 120 corresponds at most to a maximum value.

[0065] Alternatively, the maximum input power can be set by the ICE control unit 111 controlling the ICE 110 such that the torque transmitted to the pElm 120 is adjusted such that the transfer power 50 generated by the pElm 120 corresponds to a maximum value. The transfer power 50 can be selected such that battery protection is ensured.

[0066] By limiting the input power 51, as in Fig. As shown in Figure 3, damage to the battery 210 can be prevented because, even in the event of a sudden drop in input power, the battery 210 only has to absorb the maximum transfer power 51. Furthermore, the VKM 110 and the pElm 120 can continue to operate at the previous power, so that the total available power does not drop to zero.

[0067] Fig. 4 schematically shows a limitation of the input power 51 according to a further embodiment of the method according to the disclosure. Fig. 3 can be used, for example, in step S21 in Fig. 2. The y-axis of the diagram shows an electrical power provided by the battery 210. In contrast to the Fig. 3, the maximum transfer power 50 corresponds to a maximum charging power 54 of the battery 210.

[0068] The maximum charging power 54 of the battery 210 is a maximum value of the power with which the battery 210 can be charged without being damaged. The maximum charging power 54 can be a value specific to a particular battery or a particular battery type or model. The maximum charging power 54 can be determined from information provided by a battery manufacturer. The maximum charging power 54 can optionally also be a current value determined from an operating state of the battery. The maximum charging power 54 can be determined by the battery control unit 211 if the installed battery control unit 211 provides this functionality.

[0069] By limiting the input power 51, as in Fig. As shown in Figure 4, damage to the battery 210 can be prevented because, even in the event of a sudden drop in input power, the battery 210 does not have to absorb more power than its maximum charging power 54. Furthermore, the VKM 110 and the pElm 120 can continue to operate at the previous power, so that the total available power does not drop to zero.

[0070] Fig. Figure 5 schematically shows a second embodiment of the method according to the disclosure. In contrast to the Fig. 2, the setting of the maximum input power 51 involves measuring a mains voltage. Fig. The method shown in Figure 5 can, like the method in Fig. 2, in a power-split operating mode. According to the Fig. The process shown in Figure 2 begins Fig. 5 shown processes in a power-split operation or when commissioning the hybrid vehicle.

[0071] The Fig. The embodiment shown in Figure 5 comprises a determination step S51 in which it is determined whether the power-split operating mode continues, a measurement step S22 in which the mains voltage is measured, a decision step S53 in which a decision is made about a control of the pElm 120, and a control step S54 in which a control of the pElm 120 is carried out. The determination step S51 can comprise the same steps as the equivalent determination step S22 in Fig. 2.

[0072] The method begins, for example, with an optional determination step S51. If it is determined in S51 that the power-split operation, which may correspond, for example, to the decommissioning of the hybrid vehicle, is no longer ongoing ("No"), the method is terminated. If it is determined in S51 that the power-split operation is still ongoing ("Yes"), S51 is followed by the measuring step S52. In the measuring step S52, for example, by means of a measurement in a measuring device designed and available for this purpose, such as the voltage measuring device 301 in Fig. 1, the mains voltage is measured. Following the measuring step S53, a decision step determines whether the mains voltage is increasing. An increase in the mains voltage can be detected, for example, by comparing the measured mains voltage values ​​from two consecutive repetitions of the measuring step S52. There are embodiments in which the increase in the mains voltage involves calculating a gradient of the mains voltage over time, whereby a time coordinate can be provided, for example, by a system clock of a control unit or another suitable source.

[0073] The calculation of the gradient or the comparison can optionally be performed in a separate, not-shown, step and need not be included in the decision step S53. The calculation of the gradient or the comparison can also be included in the measurement step S52. Those skilled in the art may recognize other combinations, also not shown, that can be used to implement the method according to the disclosure.

[0074] If no increase in the mains voltage is detected in step S53 ("No increase"), step S51 follows step S53, in a repeated fashion. If an increase in the mains voltage is detected in step S53 ("Increase"), step S53 is followed by control step S54. In control step S54, the transfer power 50 is adjusted so that an upper voltage limit of the battery 210 is not violated. In order not to violate the upper voltage limit, the transfer power 50 can be adjusted. There is a fundamental relationship between electrical power and electrical voltage, which can be expressed, for example, using relation (1): P(Elm)=(ΔU)2⋅R

[0075] Here, P(Elm) is a power, for example, the transfer power 50, R is an internal grid resistance resulting from an operating point of the sElm 220 and the state of the battery 210, and ΔU is a voltage change, for example, the difference between the upper voltage limit and a base voltage specified by the battery 210. Therefore, if the transfer power 50 is to be reduced so that the upper voltage limit is not violated, the transfer power must be reduced while maintaining the same current. In particular, the change in the internal resistance R can be compensated via the power P(Elm) so that the voltage does not exceed the upper voltage limit.

[0076] The adjustment of the transfer power 50 can be performed by the pElm control unit 121 controlling the pElm 120 such that a generator torque of the pElm 120 is adjusted such that the transfer power 50 generated by the pElm 120 corresponds to a desired value.

[0077] Alternatively, the adjustment of the transfer power 50 can be performed by the ICE control unit 111 controlling the ICE 110 such that the torque transmitted to the pElm 120 is adjusted such that the transfer power 50 generated by the pElm 120 corresponds to a desired value. In particular, the transfer power 50 can also be set to a value of zero.

[0078] Following control step S54, step S51 is repeatedly performed. If step S51 is not provided, the method continues in step S52 instead. The method is repeated until an end of the power-split operation is detected in determination step S51.

[0079] The repetition of steps S51, which is optional, as well as S52, S53, and S54, can occur at a cadence. The cadence value can be selected, for example, within a range of 10 ms to 1 s, with larger or smaller values ​​possible.

[0080] The upper voltage limit of the battery 210 is a maximum voltage value with which the battery 210 can be charged without being damaged. The upper voltage limit can be a constant value specific to a particular battery, a particular battery type, or a particular battery model. The upper voltage limit can be determined, for example, from information provided by a battery manufacturer. The upper voltage limit can also be determined based on the battery temperature and the current state of charge of the battery.

[0081] Fig. Figure 6 schematically shows a third embodiment of the method according to the disclosure. In contrast to the Fig. In the method shown in Figure 5, the decision for control is made based on a current upper voltage limit 61. The current upper voltage limit 61 can be a voltage limit determined by the battery control unit 211 based on an operating state of the battery 210. For example, using known methods, the current upper voltage limit 61 can assume different values ​​if the battery 210 is subjected to different ambient temperatures, has different states of charge, and the like.

[0082] The Fig. Step S61 shown in Figure 6 corresponds to step S51 in Fig. 5 and the Fig. Step S62 shown in Figure 6 corresponds to step S52 in Fig. 5. Like step S51, step S61 is optional. Step S63 in Fig. 6 can be assigned to step S53 in Fig. 5, wherein instead of a constant voltage upper limit, a decision is made based on the current voltage upper limit. Alternatively, step S63 can provide that a need to carry out control step S64 ("overload") is detected when a difference between the mains voltage measured in step S62 and the current voltage upper limit is less than a predetermined value. The predetermined value can be, for example, 0.5 V. However, larger or smaller values ​​are also possible according to the disclosure. Furthermore, a need to carry out control step S64 ("overload") can be detected when the mains voltage is greater than the current voltage upper limit 61. Alternatively or in addition to determining an absolute load, a gradient of the voltage change can also be used as the basis for detecting an overload, according to the disclosure.

[0083] If no need for control is detected in step S63 (“no overload”), step S61 follows step S63.

[0084] If a need for control is detected in step S63 (“overload”), control step S64 follows step S63.

[0085] In control step S64, analogous to control step S53 in Fig. 5 the transfer power 50 is set so that the current voltage upper limit 61 of the battery 210 is not violated.

[0086] Following control step S64, step S61 is performed repeatedly. The method is repeated until the end of the power-split operation is detected in determination step S61. If determination step S61 is not provided, the method is repeated from step S62.

[0087] The repetition of steps S61, S62, S63, and S64 can occur at a cadence. The cadence value can be selected, for example, within a range of 10 ms to 1 s, with larger or smaller values ​​possible.

[0088] With the Fig. 6, it can be ensured that the current voltage upper limit 62 of the battery 210 is not violated and yet maximum traction power is available.

[0089] Fig. Figure 7 schematically shows a fourth embodiment of the method according to the disclosure. In contrast to the Fig. 6, the decision for control is made here on the basis of the current upper voltage limit 61 and the current lower voltage limit 62. In particular, the method shown in Fig. The method shown in Figure 7 includes a second decision step S74, in which a need to perform a control step S76 is determined. Step S74 is provided to detect an underload of the battery 210 due to excessive power consumption by the sElm 220.

[0090] The lower voltage limit of the battery 210 is a minimum voltage value at which the battery 210 can be discharged without being damaged. The lower voltage limit can be a value specific to a particular battery, a particular battery type, or a particular battery model. The lower voltage limit can also be determined based on the battery temperature and the current state of charge of the battery. It is important to ensure that the limit is not exceeded.

[0091] The instantaneous lower voltage limit 62 may be a lower voltage limit determined by the battery control unit 211 based on an operating state of the battery 210. For example, using known methods, the instantaneous lower voltage limit 62 may assume different values ​​when the battery 210 is subjected to different ambient temperatures, has different states of charge, and the like.

[0092] The Fig. Step S71 shown in Figure 7 corresponds to step S51 in Fig. 5 and the Fig. Step S72 shown in Figure 7 corresponds to step S52 in Fig. 5. Like step S51, step S71 is optional and can be omitted. Step S73 in Fig. 7 can be assigned to step S63 in Fig. 6 correspond.

[0093] If no need for control ("no overload") is detected in step S73, step S74 follows step S73. If a need for control ("overload") is detected in step S73, control step S75 follows step S73.

[0094] In control step S75, analogous to control step S64 in Fig. 6 the transfer power 50 is set so that the current voltage upper limit 61 of the battery 210 is not violated.

[0095] Following control step S75, step S71 is performed repeatedly. The method is repeated until the end of the power-split operation is detected in the optional determination step S71. If determination step S71 is not provided, the method is repeated from step S72.

[0096] In the second decision step S74, a need to perform control step S76 ("underload") is detected. Underload can be detected if the difference between the grid voltage measured in measurement step S72 and the current voltage lower limit 62 is less than a predetermined value. The predetermined value can be, for example, 0.5 V. However, larger or smaller values ​​are also possible according to the disclosure. Furthermore, a need to perform control step S76 ("underload") can be detected if the grid voltage is less than the current voltage lower limit 62.

[0097] If no need for control ("no underload") is detected in step S74, step S74 is repeated by step S71. If a need for control ("underload") is detected in step S74, control step S76 follows step S74.

[0098] In control step S76, the input power 51 is adjusted so that the current lower voltage limit 62 of the battery 210 is not violated. If the lower voltage limit 62 is violated, this means that the input power 51 transmitted by the battery 210 to the sElm 220 is too high. Therefore, if the grid voltage value is lower than the current lower voltage limit 62, the input power 51 of the sElm 220 can be reduced to increase the grid voltage value.

[0099] The input power 51 can be adjusted by the sElm control unit 221 controlling the sElm 220 such that a motor torque of the sElm 220 is adjusted such that the input power 51 consumed by the sElm 120 corresponds to a desired value. In particular, the input power 51 can be adjusted such that the current voltage lower limit 62 is not violated or undershot.

[0100] Following control step S76, step S71 is performed repeatedly. The method is repeated until the end of the power-split operation is detected in the optional determination step S71. If determination step S71 is not provided, the method is repeated following S76 starting from step S72.

[0101] The repetition of steps S71, S72, S73, S74, S75, and S76 can occur at a cadence. The cadence value can be selected, for example, in a range from 10 ms to 1 s, or a frequency in a range from 6 to 10 kHz, with larger or smaller values ​​possible. It is also possible for the battery to be regulated at a different cadence. For example, a cadence of 10 ms may be specified, but the battery may be regulated at a cadence of 100 ms.

[0102] It should be noted that the order of the steps in Fig. 7 can be modified and still ensure that the method can be carried out in accordance with the disclosure. In particular, steps S73 and S74 can be interchanged. A person skilled in the art may notice other sequences or combinations of the illustrated steps that lead to the implementation of the method according to the disclosure. Tasks to be performed, which are depicted here in different steps, can also be performed in more or fewer steps if necessary.

[0103] With the Fig. 7, it can be ensured that neither the instantaneous upper voltage limit 61 nor the instantaneous lower voltage limit 62 of the battery 210 is violated, whereby the battery 210 is optimally protected from damage during charging and discharging operations and yet maximum traction power is available.

[0104] There are embodiments in which the Fig. 2, Fig. 5, Fig. 6 and Fig. 7 shown methods can be combined.

[0105] Fig. 8 schematically shows a possible control scheme of a battery load control system 1000 according to the disclosure, comprising a processor unit (CPU) 1001, an optional communication unit 1002, an optional sensor arrangement 1003, an optional user interface 1004, an optional control interface 1005 and an optional data memory 1006.

[0106] The CPU 1001 is designed to carry out the disclosed method and can be provided as a microprocessor, a virtual computer unit, or another programmable computer unit. The CPU 1001 can be a CPU of a vehicle control unit or the vehicle control unit. The CPU 1001 can also be a CPU of a control unit of a vehicle component. For example, the CPU 1001 can be a CPU of the ICE control unit 111, the pElm control unit 121, the battery control unit 211, or the sElm control unit 221. For example, the CPU 1001 can also be the ICE control unit 111, the pElm control unit 121, the battery control unit 211, or the sElm control unit 221. The CPU can be designed as a plurality of components that are designed to cooperate to carry out the disclosed method.

[0107] The optional communication unit 1002 is configured to receive control signals from or send them to external sources, for example, control units or user terminals. The control signals can be received or sent via wired media or wirelessly, for example, via radio signals. The communication unit 1002 is also configured to receive information from or send it to external sources, for example, control units or user terminals. The information can be received or sent via wired media or wirelessly, for example, via radio signals, which the control interface is configured to generate.

[0108] The optional sensor arrangement 1003 is configured to measure environmental information or information about an operating state of components and provide it to the CPU 1001. For example, the sensor arrangement 1003 may include the voltage measuring device 301.

[0109] The optional user interface 1004 is configured to provide a user with information about an operating state of the load control system 1000. For this purpose, the user interface can be equipped with a visual display unit, for example, a display, and an acoustic display unit, for example, a loudspeaker and other types of display units. Furthermore, the user interface 1004 can be configured to receive instructions from a user. For this purpose, the user interface can be equipped with a touch display, a keyboard, voice recognition, or the like.

[0110] The optional control interface 1005 is configured to transmit control signals to vehicle components, for example, the VKM 110, the pElm 120, the battery 210, or the sElm 220. The transmission can be done via wired media or wirelessly, for example, via radio signals, which the control interface is configured to generate.

[0111] The data storage 1006 is configured to store information in digital form and make it available to the CPU 1001. The information can be transferred to the data storage 1006 from the CPU 1001, the optional communication unit 1002, the optional sensor arrangement 1003, the optional user interface 1004, or the optional control interface 1005. The data storage can be provided in a known manner as a hard disk, a random access memory (RAM), a solid-state disk (SSD), or other suitable device.

[0112] The method according to the disclosure may in particular be provided as follows: (1) A method for load control of a battery 210 in a power-split operation of a hybrid vehicle 1, comprising: adjusting a transfer power of a primary electric machine 120 to the battery 210 such that the battery 210 is protected from damaging loads during a low-load phase; wherein the battery 210 is configured to provide an input power 51 for the secondary electric machine 220 and to absorb the transfer power from the primary electric machine 120. (2) The method according to (1), wherein adjusting the transfer power comprises limiting the input power 51 to a maximum input power 51; and the maximum input power 51 is a sum of a maximum discharge power 52 of the battery 210 and a maximum transfer power 50. (3) The method of any one of (1) or (2), wherein the maximum transfer power 50 is a maximum charging power 54 of the battery. (4) The method according to any one of (1) to (3), further comprising: measuring a grid voltage by a control unit 121 of the primary electric machine 120, and adjusting the transfer power by adjusting a generator torque of the primary electric machine 120 based on the grid voltage by the control unit of the primary electric machine 120; such that a voltage upper limit 61 of the battery 210 is not violated. (5) The method according to any one of (1) to (4), wherein the upper voltage limit 61 of the battery 210 is determined by a control unit 211 of the battery 210; and the setting of the transfer power is performed based on the upper voltage limit 61 of the battery 210. (6) The method of any one of (1) to (5), wherein adjusting the transfer power comprises reducing the generator torque of the primary electric machine 120 upon an increase in the grid voltage. (7) The method according to any one of (1) to (6), further comprising: adjusting the input power 51 by adjusting a motor torque of the secondary electric machine 220 based on the grid voltage by the control unit of the secondary electric machine 221; such that a lower voltage limit 62 of the battery 210 is not violated; wherein the lower voltage limit 62 of the battery 210 is determined by a control unit 211 of the battery 210, and the adjustment of the input power 51 is based on the lower voltage limit 62 of the battery 210. (8) Method according to one of (1) to (7), wherein the adjustment of the input power 51 comprises a reduction of the motor torque of the secondary electric machine 220 when the mains voltage is reduced. (9) A battery load control system 1000 configured to perform the method of any one of (1) to (8). (10) Hybrid vehicle 1 comprising the battery load control system 1000 according to (9). List of reference symbols 1 hybrid vehicle 2-9 subject to change 10 Primary axis 11-19 subject to change 20 Secondary axis 21-29 subject to change 30 coupling element 31-49 subject to change 50 maximum transfer performance 51 recording power 52 maximum discharge power 53 subject to change 54 maximum charging power 55-60 subject to change 61 Voltage limit 62 Lower voltage limit 63-99 subject to change 100 primary unit 101-109 subject to change 110 Internal combustion engine (VKM) 111 ICE control unit 112-119 subject to change 120 primary electric machine (pElm) 121 pElm control unit 122-199 subject to change 200 secondary unit 201-209 subject to change 210 Battery 211 Battery control unit 212-219 subject to change 220 secondary electric machine (sElm) 221 sElm control unit 222-299 subject to change 300 primary electrical connection 301 Voltage measuring device 302 switching element 303-999 subject to change 1000 Battery Load Control System 1001 processor unit 1002 Communication unit 1003 Sensor arrangement 1004 User Interface 1005 Control interface 1006 data storage QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 103 39 803 A1

[0002] GB 2594276

[0003] DE 10 2014 110 860 A1

[0004]

Claims

[1] Method for load control of a battery (210) in a power-split operation of a hybrid vehicle (1), comprising: Adjusting a transfer power of a primary electric machine (120) to the battery (210) such that the battery (210) is protected from damaging loads during a low-load phase; wherein the battery (210) is configured to provide an input power (51) for the secondary electric machine (220) and to receive the transfer power from the primary electric machine (120). [2] The method of claim 1, wherein adjusting the transfer power comprises limiting the input power (51) to a maximum input power (51); and the maximum input power (51) is a sum of a maximum discharge power (52) of the battery (210) and a maximum transfer power (50). [3] The method of claim 2, wherein the maximum transfer power (50) is a maximum charging power (54) of the battery. [4] The method of claim 1, further comprising: Measuring a grid voltage by a control unit (121) of the primary electric machine (120), and adjusting the transfer power by adjusting a generator torque of the primary electric machine (120) based on the grid voltage by the control unit of the primary electric machine (120); such that a voltage upper limit (61) of the battery (210) is not violated. [5] The method according to claim 4, wherein the upper voltage limit (61) of the battery (210) is determined by a control unit (211) of the battery (210); and the setting of the transfer power is based on the upper voltage limit (61) of the battery (210). [6] Method according to one of claims 4 or 5, wherein adjusting the transfer power comprises reducing the generator torque of the primary electric machine (120) when the grid voltage increases. [7] A method according to any one of claims 1 to 6, further comprising: Adjusting the input power (51) by adjusting a motor torque of the secondary electric machine (220) on the basis of the mains voltage by the control unit of the secondary electric machine (221); such that a lower voltage limit (62) of the battery (210) is not violated; wherein the lower voltage limit (62) of the battery (210) is determined by a control unit (211) of the battery (210), and the adjustment of the input power (51) is carried out on the basis of the lower voltage limit (62) of the battery (210). [8] Method according to claim 7, wherein adjusting the input power (51) comprises a reduction of the motor torque of the secondary electric machine (220) when the mains voltage is reduced. [9] Battery load control system (1000) designed to carry out the method according to one of claims 1 to 8. [10] A hybrid vehicle (1) comprising the battery load control system (1000) according to claim 9.

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