WO2018177647A1

WO2018177647A1 - Method and device for compensating pulsations in a torque acting on a shaft

Info

Publication number: WO2018177647A1
Application number: PCT/EP2018/053679
Authority: WO
Inventors: Markus Kretschmer
Original assignee: Robert Bosch Gmbh
Priority date: 2017-03-31
Filing date: 2018-02-14
Publication date: 2018-10-04
Also published as: DE102017205489A1

Abstract

Method (400) for compensating pulsations in a torque acting on a shaft (30), with a fired internal combustion engine (10) and an electric machine (20). The shaft (30) is operatively connected on the one hand to the crankshaft (12) of the internal combustion engine (10) and on the other hand to the rotor (22) of the electric machine (20). The method comprises the steps of: predefining (410) a desired torque (M_W) for operating the electric machine (20); determining (420) a damping torque (M_D) for compensating pulsations depending on the torque (M_V) output by the fired internal combustion engine (10), and determining (430) a setpoint torque (M_E_Soll), to be prescribed to the electric machine (20), depending on the desired torque (M_W) and on the determined damping torque (M_D).

Description

Description title

Method and device for vibration compensation of a torque acting on a shaft

The invention relates to a method and a device for vibration compensation of a torque acting on a shaft. Furthermore, the invention relates to a component arrangement with a corresponding device and a vehicle with a component arrangement, as well as a computer program and a machine-readable storage medium.

State of the art

Vehicles with a hybrid powertrain are known in the art. A hybrid drive train of a vehicle comprises at least two drive units, which can drive the vehicle individually or jointly. For example, a first drive unit is an internal combustion engine. As the second drive unit, an electric machine or a hydraulic motor can be used by way of example. Due to the design, a hydraulic motor outputs drive torque more uniformly than an electric machine and more evenly than an internal combustion engine, in particular with a small number of cylinders, for example less than 5 cylinders. In particular, in internal combustion engines, therefore, one speaks of rotationally non-uniformities of the internal combustion engine. As already shown, in a hybrid drive train, the at least two drive units can cooperate. Therefore, it is known that the design-related rotational irregularities of a fired internal combustion engine, for example, by means of a direct coupling with an electric machine with appropriate control of the electric machine can be miniert. This is known, for example, from WO 0163122. There, to start the internal combustion engine, the latter is connected to the electrical engine are driven and the electric machine is controlled so that the rotational irregularities of the internal combustion engine are minimized. There is a need to provide alternative control methods and apparatus for reducing the rotational uniformity of hybrid powertrains.

Disclosure of the invention

A method is provided for vibration compensation of a torque acting on a shaft, with a fired internal combustion engine and an electric machine, wherein the shaft is operatively connected on the one hand to the crankshaft of the internal combustion engine and on the other hand to the rotor of the electric machine. The method comprises the steps of receiving and / or preselecting a desired torque for the operation of the electric machine, determining a damping torque for vibration compensation as a function of the torque output by the fired internal combustion engine and determining a desired torque to be preset for the electric machine as a function of the desired torque and the determined damping torque.

A method is provided for vibration compensation of a torque acting on a shaft. The torque acting on the shaft results from the coupling of this shaft on the one hand with a crankshaft of an internal combustion engine and on the other hand with a rotor of an electric machine. These couplings of the shaft can be done mechanically rigid, gear or damping means. For a rigid connection, for example, the crankshaft, the shaft and the rotor of the electric machine can be made in one piece. Due to the coupling of this shaft, on the one hand with an internal combustion engine and the other with an electric machine act on this wave, the unevenly emitted torque of the fired internal combustion engine on the one hand and the uniform output torque of the electric machine on the other. The aim of the method is to minimize the uneven torque acting on the shaft by means of a corresponding counteracting control of the electric machine. The method for this includes, as a first step, receiving and / or anticipating ben of a desired torque for the operation of the electric machine. This desired torque may be a positive torque of the electric machine in the event that the internal combustion engine and the electric machine cooperate and, for example, drive a vehicle. The desired torque can be received by another control unit, for example as a function of an accelerator pedal position and other torque requirements of a vehicle (air conditioner, steering, ..) or directly specified, also in particular depending on, for example, the above sizes. This desired torque may be a negative torque for the case that the electric machine is operated as a generator for generating electrical energy from the rotational energy of the fired internal combustion engine. Furthermore, in the method, a damping torque is determined, which is suitable for vibration compensation of the torque acting on the shaft, as a function of the torque delivered by the fired internal combustion engine. Depending on the desired torque and the determined damping torque, a desired torque to be preset for the electric machine is determined. A method for vibration compensation is advantageously provided in which a setpoint torque to be preset for the electric machine is determined as a function of a desired torque and a determined damping torque.

In another embodiment of the invention, the determination of the damping torque in dependence on the speed of the electric machine.

The determination of the damping torque takes place as a function of the rotational speed of the electric machine. By means of sensors, in particular rotational speed sensors or encoder wheel sensors, or by means of an evaluation of the measured phase voltages or phase currents of an electrical machine, the rotational speed and / or the angular position of the electrical machine can be determined very accurately. Due to the mechanical operative connection of the shaft with the internal combustion engine and the electric machine, the uneven torque output of the internal combustion engine can be deduced by means of the rotational speed of the electric machine and therefore the damping torque for the oscillation compensation as a function of the rotational speed of the electric machine. be determined. Advantageously, a possibility for determining the damping torque is provided.

In another embodiment of the invention, a vibration component of the rotational speed of the electric machine is determined to determine the damping torque as a function of the rotational speed of the electric machine.

From the rotational speed of the electric machine, a vibration component of the rotational speed of the electric machine is determined and from this the damping torque for vibration compensation of a torque acting on the shaft is determined. The uneven output of the torque of the fired internal combustion engine is the cause of the vibration component of the rotational speed of the electric machine. This vibration component is the basis for determining a damping torque for vibration compensation. Advantageously, a possibility for determining the damping torque is provided.

In another embodiment of the invention, the vibration component of the rotational speed of the electric machine is determined by means of a bandpass filter.

By means of a bandpass filter, the rotational speed of the electric machine is filtered while the vibration component of the rotational speed of the electric machine is determined. The bandpass filter extracts a specific frequency spectrum from the rotational speed of the electric machine. Vibrations with frequencies that occur below or above the cutoff frequencies of a bandpass filter are filtered out. This ensures that the vibration component of the rotational speed of the electric machine contains only the information or frequency components relevant for vibration compensation. Advantageously, a method for determining the vibration component of the rotational speed of the electric machine is provided.

In another embodiment of the invention, the corner frequencies of the bandpass filter are determined as a function of an operating point, in particular of the internal combustion engine and / or the electric machine. An operating point, in particular of the internal combustion engine and / or the electric machine, is determined, and in dependence thereon the corner frequencies of the bandpass filter are determined. Depending on the operating point different corner frequencies are determined and used for the bandpass filter to determine the vibration component of the speed of the electric machine. In particular, the frequency ranges relevant for the vibration compensation change as a function of the operating point of the internal combustion engine. Therefore, for an efficient determination of the oscillation component of the rotational speed of the electrical machine, the corner frequencies of the bandpass filter are determined as a function of the operating point. Advantageously, a method is provided for determining the corner frequencies of the bandpass filter.

In another embodiment of the invention, the operating point is determined as a function of the rotational speed of the electric machine, in particular depending on the speed of the electric machine filtered by means of a low-pass filter.

Depending on the speed of the electric machine, the operating point, in particular of the internal combustion engine, is determined. In particular, the operating point is determined as a function of the speed of the electric machine filtered by means of a low-pass filter. Again, due to the active compound of

Internal combustion engine, shaft and rotor of the electric machine can be closed depending on the speed of the electric machine to the operating point, in particular of the fired internal combustion engine. Advantageously, a possibility for determining the operating point is provided.

Furthermore, the invention relates to a computer program that is configured to carry out the methods described so far.

Furthermore, the invention relates to a machine-readable storage medium on which the computer program described is stored.

Furthermore, the invention relates to a device for vibration compensation of a torque acting on a shaft. The shaft is in this case on the one hand operatively connected to a crankshaft of an internal combustion engine and on the other hand with a rotor of an electric machine. The connection is for example rigid, geared or damped. The device further comprises means for predetermining or receiving a desired torque for the operation of the electric machine, determining a damping moment for vibration compensation as a function of the torque delivered by the fired internal combustion engine, and determining a desired torque to be preset for the electric machine as a function of the desired torque and the determined damping torque ,

A device is provided for vibration compensation of a torque acting on a shaft. The torque acting on the shaft results from the coupling of this shaft on the one hand with a crankshaft of an internal combustion engine and on the other hand with a rotor of an electric machine. These couplings of the shaft can be done mechanically rigid, gear or damping means. For a rigid connection, for example, the crankshaft, the shaft and the rotor of the electric machine can be made in one piece. Due to the coupling of this shaft, on the one hand with an internal combustion engine and the other with an electric machine act on this wave, the unevenly emitted torque of the fired internal combustion engine on the one hand and the uniform output torque of the electric machine on the other. The aim of the method is to minimize the uneven torque acting on the shaft by means of a corresponding counteracting control of the electric machine. For this purpose, means are provided which allow predetermining and / or receiving a desired torque for the operation of the electrical machine. The desired torque can be received by another control device, for example as a function of an accelerator pedal position and further torque requirements of a vehicle (air conditioning unit, steering, etc.) from a means or be specified directly in the means, also in particular depending on, for example, the variables mentioned. Furthermore, there is a means which determines a damping moment. This damping torque is suitable for vibration compensation of the torque acting on the shaft, as a function of the torque output by the fired internal combustion engine. Furthermore, a means is provided for determining a setpoint torque to be preset for the electric machine as a function of the desired torque and the determined damping torque. Advantageously, a Direction for vibration compensation provided for determining a predetermined electrical torque of the machine torque in dependence on a desired torque and a determined damping torque.

Furthermore, the invention relates to a component arrangement with an electric machine and an internal combustion engine and a described device. In particular, the component arrangement comprises power electronics and a battery. Such a component arrangement comprises, for example, a hybrid drive train or in particular a drive train of a range extender. A drive train of a range extender is characterized in that the internal combustion engine can not be coupled to drive wheels of the vehicle but can only be coupled to an electric machine. In regenerative operation, the electric machine is driven by the internal combustion engine and generates electrical energy. The electrical energy is either initially stored in a battery or used directly for the electric drive, for example, a vehicle. By means of such a component arrangement is advantageously provided a vibration compensation on a shaft of a hybrid drive train.

Furthermore, the invention relates to a vehicle with a described component arrangement. Advantageously, a vehicle is thus provided which provides a device for vibration compensation of a torque acting on a shaft.

It is understood that the features, properties and advantages of the method according to the invention apply correspondingly to the device or the component arrangement and the vehicle and vice versa.

Further features and advantages of embodiments of the invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings In the following, the invention will be explained in more detail with reference to some figures, in which:

FIG. 1

a schematic representation of a device for vibration compensation of a torque acting on a shaft.

FIG. 2

a schematically illustrated vehicle with a device, Figure 3

1 is a schematically illustrated flow diagram for a method for vibration compensation of a torque acting on a shaft;

FIG. 4

a signal flow diagram for a method for vibration compensation of a torque acting on a shaft.

Embodiments of the invention

FIG. 1 shows a component arrangement 100 with a device 40 for vibration compensation of a torque acting on a shaft 30. The shaft 30 connects a crankshaft 12 of an internal combustion engine 10 to a rotor 22 of an electric machine 20. The shaft 30 can be rigidly connected to the crankshaft 12 and the rotor 22. Similarly, the shaft 30 may be connected to the crankshaft 12 or the rotor 22 of the electric machine 20 via a transmission (not shown) or by means of damping means. Also shown is a pulse inverter 50, which is configured to convert regeneratively generated electrical energy of the electric machine 20 into a DC voltage and to feed it into a battery 60 or vice versa to operate the electric machine 20 by a motor and for this purpose electrical energy from the Battery 60 in an AC voltage to supply the electric machine 20 to convert. The device 40 for vibration compensation of a torque acting on the shaft 30 comprises means, not shown, for selecting a desired torque M_W for the operation of the electrical machine 20, for example, to receive from another control device or pretend for the operation of the electrical machine. Furthermore, the device 40 comprises means for determining a damping moment M_D for vibration compensation as a function of the torque M_V output by the fired internal combustion engine 10 and determining a desired torque M_E_Soll depending on the desired torque M_W and the determined damping torque M_D and for the pulse inverter 50 for to transmit the control of the electric machine 20.

FIG. 2 shows a vehicle 200 with a component arrangement 100 which serves as a drive train, for example for at least one of the drive wheels 210 of the vehicle 200.

3 shows a schematic sequence of a method 400 for vibration compensation of a torque acting on a shaft 30, wherein the shaft 30 is operatively connected on the one hand to the crankshaft 12 of a fired internal combustion engine 10 and on the other hand to the rotor 22 of an electric machine 20. The method starts with step 405. In step 410, a desired torque M_W for the operation of the electric machine 20 is received or predetermined. In step 420, a damping torque M_D for vibration compensation is determined as a function of the torque M_V output by the fired internal combustion engine 10. In step 430, one of the setpoint torque M_E_Soll to be preset for the electric machine 20 is determined as a function of the desired torque M_W and the determined damping torque M_D. This determined setpoint torque M_E_Soll is in particular transmitted to a pulse-controlled inverter 50 for controlling the electric machine 20. At step 435, the process ends.

FIG. 4 shows a signal flow diagram for determining a setpoint torque M_E_Soll which is given to an electric machine for vibration compensation of a torque acting on a shaft 30. Depending on the desired torque M_W for the operation of the electric machine 20 and a damping torque M_D for vibration compensation, the setpoint torque M_E_Soll is determined in a logic device E_3. to Determining the damping torque M_D, the rotational speed of the electric machine M_E is filtered by means of a bandpass filter F_B for generating a vibration component N_S of the rotational speed N_E of the electric machine 20. Depending on the vibration component N_S, the damping torque M_D is determined by means of a logic unit E_2, which, for example, is stored in a characteristic map. To generate the corner frequencies of the bandpass filter F_B, the speed N_E of the electric machine 20 is filtered by means of a low-pass filter F_T. From this signal, the operating point in particular of the fired internal combustion engine and / or the electric machine 20 can be determined. This information about the operating point is fed to a logic device E_l. As output signals, the logic unit E_1, for example based on map data, outputs the corner frequencies F_B_E1 and F_B_E2 for the bandpass filter F_B. Advantageously, by means of this signal flow diagram, a possibility is provided for determining a setpoint torque M_E_Soll to be preset for the electric machine 20 for vibration compensation of a torque acting on a shaft.

Claims

claims

A method (400) for vibration compensation of a torque acting on a shaft (30),

with a fired internal combustion engine (10) and an electric machine (20),

wherein the shaft (30) is operatively connected on the one hand to the crankshaft (12) of the internal combustion engine (10) and on the other hand to the rotor (22) of the electric machine (20),

with the steps:

Receiving and / or prescribing (410) a desired torque (M_W) for the operation of the electric machine (20);

Determination (420) of a damping torque (M_D) for vibration compensation as a function of the fired by the internal combustion engine (10) torque (M_V) and

Determining (430) of a setpoint torque (M_E_Soll) to be preset for the electric machine (20) as a function of the desired torque (M_W) and of the determined damping torque (M_D).

2. The method according to claim 1,

wherein the determination (420) of the damping torque (M_D) takes place as a function of the rotational speed (N_E) of the electrical machine.

3. The method according to claim 2,

wherein for determining (420) of the damping torque (M_D) as a function of the rotational speed (N_E) of the electric machine (20), a vibration component (N_S) of the

Speed (N_E) of the electrical machine (20) is determined.

4. The method according to claim 3,

wherein the vibration component (N_S) of the rotational speed (N_E) of the electric machine (20) is determined by means of a bandpass filter (F_B).

5. The method according to claim 4

wherein the corner frequencies (F_B_E1, F_B_E2) of the bandpass filter (F_B) are determined as a function of an operating point (B), in particular of the internal combustion engine (10) and / or the electric machine (20).

6. The method according to claim 5,

wherein the operating point (B) is determined as a function of the rotational speed (N_E) of the electric machine (20), in particular as a function of the rotational speed (N_E) of the electric machine (20) filtered by means of a low-pass filter (F_T).

A computer program configured to execute the method (400) of any of claims 1-6.

8. A machine-readable storage medium on which the computer program according to claim 7 is stored.

9. Device (40) for vibration compensation of a shaft (30) acting torque,

wherein the shaft (30) is operatively connected, on the one hand, to a crankshaft (12) of an internal combustion engine (10) and, on the other hand, to a rotor (22) of an electrical machine (20),

and the device (40) comprises means to

receive or specify a desired torque (M_W) for the operation of the electrical machine (20),

to determine a damping torque (M_D) for vibration compensation as a function of the torque (M_V) emitted by the fired internal combustion engine (10) and

to determine a setpoint torque (M_E_Soll) to be preset for the electrical machine (20) as a function of the desired torque (M_W) and of the determined damping torque (M_D).

10. Component arrangement (100) with an electric machine (20) and an internal combustion engine (10) and a device (40) according to claim 9 and in particular a power electronics (50) and / or a battery (60).

11. Vehicle (200) with a component arrangement (100) according to claim 10.