DE102021109721A1 - Electric propulsion system, method for controlling an electric propulsion system, computer program product and control unit - Google Patents

Abstract

The invention relates to an electric drive system (1) for a vehicle (100) that can be operated with muscle power, comprising a first electric machine (2) that can be operated as a motor and acts on a drive wheel (101) of the vehicle (100) for the purpose of driving , a second electrical machine (3) that can be operated as a generator, which is set up to convert mechanical energy introduced by a driver of the vehicle (100) via a pedal-operated actuating device (15) into electrical energy, and a central control unit (5) for controlling the first electrical machine (3) and for controlling the second electrical machine (2) in such a way that an electrically induced rotation of the drive wheel (101) can be generated by muscle power-induced rotation of the actuating device (15) by using muscle power to act on the actuating device (15) acting drive torque (7) a manipulated variable (9) for a motor target torque (8) is calculated, where in which the control unit (5) is also set up, within the first half rotation of the actuating device (15), the phase offset (6) between the drive torque (7) applied to the second electrical machine (3) by muscle power and the motor calculated therefrom and offset in time - to determine the target torque (8), wherein in a second half rotation of the actuating device (15), the motor target torque (8) is shifted by the determined phase offset (6), so that the motor target torque ( 8) and the drive torque (7) are essentially synchronous in time.

Description

The present invention relates to an electrical drive system for a vehicle that can be operated with muscle power, comprising a first electrical machine that can be operated at least as a motor and acts on a drive wheel of the vehicle for the purpose of driving, a second electrical machine that can be operated at least as a generator, which is set up mechanical energy introduced by a driver of the vehicle via a pedal-operated actuating device is to be converted into electrical energy, an energy storage device for storing and delivering electrical energy, and a central control unit for activating the first electric machine and for activating the second electric machine of the type that an electrically induced rotation of the drive wheel can be generated by a muscle power-induced rotation of the actuating device by a manipulated variable for a from the muscle power acting on the actuating device drive torque Motor target torque is calculated. The invention also relates to a method for controlling an electric drive system, a computer program product and a control unit.

In addition to conventional motor vehicles, especially passenger cars, society is increasingly focusing on small vehicles in order to meet changing mobility requirements in a future-proof manner. The small vehicles have the advantage that, on the one hand, they take up less space than a parking space. On the other hand, the smallest vehicles can be designed in such a way that they can move significantly in city traffic, so that the requirements for possible maximum speeds are very low.

Traditionally, this group of small vehicles also includes, for example, bicycles, which were and are usually operated with muscle power. In addition to the human-powered bicycles, bicycles with auxiliary motors were also developed. With the development of powerful batteries, the auxiliary motors were implemented as environmentally friendly electric motors. Such electric bicycles have now become an integral part of the street scene. These muscle-assisted or pedal-assisted vehicles are known in particular under the names pedelec (pedal electric cycle), e-bike or electric bicycle.

From the DE 10 2013 012 208 A1 such an electrical drive system for a vehicle operated with muscle power is already known, the electrical drive system having at least one electrical generator mechanically connected to a drive crank, an electrical drive motor, an electrical energy store and an electrical circuit arrangement for electrically coupling the generator to the drive motor and the energy store includes.

There are also various concepts for dispensing with the endless traction means, which are subject to mechanical wear, for transmitting muscle power in electrified drive trains. These concepts are also known under the name chainless drive (CLD), in which, for example, a bicycle chain is completely dispensed with.

In conventional chainless drive (CLD) systems, the generator, which is driven by the driver via the cranks, uses electronics to generate a direct current, which can be used to charge a battery and/or drive a drive motor with controllable/adjustable current independently of the generator speed . Since there is no longer a direct mechanical connection between the driver and the driven wheel with a chainless drive, the driving experience of a mechanical drive train must be electronically simulated by the chainless drive system.

For this purpose, a torque or speed value is usually calculated by a control unit and control software of the chainless drive system on the basis of input parameters from the CLD bottom bracket module, such as angle of rotation, speed, torque, acceleration signals, etc converted into vehicle propulsion. However, the calculation of the required parameters and the conversion of the drive motor into thrust that the driver can feel takes a certain amount of time, so that the drive torque introduced by muscle graft on a pedaling unit and the motor torque brought onto the road show a phase shift. If this phase shift is large, the time or angle-delayed feed is perceived by the driver as unpleasant or at least unfamiliar.

It is therefore the object of the present invention to provide an electric drive system for a vehicle that can be operated with muscle power, which implements a very natural driving feel oriented towards a mechanical drive system. It is also the object of the invention to implement an improved method for controlling a corresponding drive system. Finally, it is also the object of the invention to provide a computer program product and a control unit of the improved method.

This object is achieved by an electrical drive system for a vehicle that can be operated with muscle power, comprising a first electrical machine that can be operated at least as a motor, which acts on a drive wheel of the vehicle for the purpose of driving, a second electrical machine that can be operated at least as a generator, which is set up to convert mechanical energy introduced by a driver of the vehicle via a pedal-operated actuating device into electrical energy, an energy storage device for storing and delivering electrical energy, and a central control unit for actuating the first electrical machine and for actuating the second electrical machine of the type that an electrically induced rotation of the drive wheel can be generated by muscle power-induced rotation of the actuating device by a manipulated variable for a mot from the muscle power acting on the actuating device drive torque pre-desired torque is calculated, the control unit also being set up to determine at least half a revolution of the actuating device connected to the second electric machine and the phase offset between the drive torque applied to the second electric machine by muscle power and the time-staggered drive torque calculated therefrom Provide motor target torque, wherein the motor target torque is shifted by the provided phase offset, so that the motor target torque and the drive torque are substantially synchronous in time.

The electric drive system according to the invention can impart a particularly natural driving experience in that the torque curves of the drive and the motor are synchronized.

The phase offset can be provided, for example, by the phase offset being stored in the control unit. However, it would also be conceivable to determine the phase offset dynamically during operation of the electric drive system. For this purpose, the control unit can then be set up to determine a first half rotation of the actuating device connected to the second electric machine and, within the first half rotation of the actuating device, to determine the phase offset between the drive torque applied to the second electric machine by muscle power and the calculated from it, as well as temporally offset motor target torque to determine, from a second half revolution of the actuator, the motor target torque is shifted by the determined phase offset, so that the motor target torque and the drive torque are substantially synchronous in time.

It is therefore proposed to calculate only the first pedaling impulse, represented by the first half turn of the actuating device, directly after a pedaling break (e.g. also when starting a journey) and on the drive motor via a correspondingly calculated manipulated variable for a target motor torque with a corresponding To implement the phase shift, from the subsequent pedaling impulse, this is then converted into a manipulated variable for a target motor torque on the drive motor based on the phase shift of the system calculated in the first pedaling impulse, so that the target motor torque and the drive torque on the Actuator essentially run synchronously in time.

The vehicle can be designed as a bicycle, in particular as an electric bicycle, e.g. as a pedelec or as an e-bike. For example, the vehicle can be a transport or cargo bike, in particular a motorized or electrically driven transport or cargo bike, in particular a three-wheel or four-wheel pedelec or a rickshaw, in particular with or without a roof, or a cabin scooter.

In principle, it would of course also be conceivable for a plurality of electrical machines that can be operated as motors to be coupled to a machine that can be operated as a generator. In this way, for example, a multi-axle drive concept or all-wheel drive could be implemented in a multi-lane vehicle. It would also be possible for several machines that can be operated as a generator to be coupled with one machine that can be operated electrically, so that tandem drive concepts, for example, in which, for example, two people feed muscle power into the drive system, can be implemented. Finally, it is also possible to further develop the drive concept by coupling a plurality of electrical machines that can be operated as generators with a plurality of electrical machines that can be operated as motors.

1. a. Ermittlung einer halben Umdrehung der mit der zweiten elektrischen Maschine verbundenen Betätigungseinrichtung,
2. b. Ermittlung des Phasenversatzes innerhalb der ersten halben Umdrehung der Betätigungseinrichtung zwischen dem an der zweiten elektrischen Maschine durch Muskelkraft aufgebrachten Antriebsdrehmoment und dem daraus berechneten sowie zeitlich versetzten Motor-Soll-Drehmoment,
3. c. Verschieben des Motor-Soll-Drehmoments um den ermittelten Phasenversatz, so dass das Motor-Soll-Drehmoment und das Antriebsdrehmoment zeitlich im Wesentlichen synchron verlaufen.

The object of the invention is also achieved by a method for controlling an electric drive system for a vehicle that can be operated with muscle power, comprising
a first electrical machine that can be operated at least as a motor, which acts on a drive wheel of the vehicle for the purpose of driving, a second electrical machine that can be operated at least as a generator, which is set up to convert mechanical energy introduced by a driver of the vehicle via a pedal-operated actuating device into electrical energy To convert energy, an energy storage device for storage and for Delivery of electrical energy, as well as a central control unit for controlling the first electric machine and for controlling the second electric machine in such a way that a muscle-powered rotation of the actuating device can be used to generate an electrically-induced rotation of the drive wheel by using the muscle power acting on the actuating device Drive torque, a manipulated variable for a target engine torque is calculated, comprising the following steps:

1. a. Determination of half a revolution of the actuating device connected to the second electrical machine,
2. b. Determination of the phase offset within the first half revolution of the actuating device between the drive torque applied to the second electric machine by muscle power and the motor target torque calculated from this and offset in time,
3. c. Shifting the target motor torque by the determined phase offset, so that the target motor torque and the drive torque are substantially synchronous in time.

1. a. Ermittlung einer ersten halben Umdrehung der mit der zweiten elektrischen Maschine verbundenen Betätigungseinrichtung,
2. b. Ermittlung eines Phasenversatzes innerhalb der ersten halben Umdrehung der Betätigungseinrichtung zwischen dem an der zweiten elektrischen Maschine durch Muskelkraft aufgebrachten Antriebsdrehmoment und dem daraus berechneten sowie zeitlich versetzten Motor-Soll-Drehmoment,
3. c. Verschieben des Motor-Soll-Drehmoments ab einer zweiten halben Umdrehung der Betätigungseinrichtung, um den ermittelten Phasenversatz, so dass das Motor-Soll-Drehmoment und das Antriebsdrehmoment zeitlich im Wesentlichen synchron verlaufen.

The method can also be further developed in such a way that method steps ac are modified as follows:

1. a. Determination of a first half revolution of the actuating device connected to the second electrical machine,
2. b. Determination of a phase offset within the first half rotation of the actuating device between the drive torque applied to the second electric machine by muscle power and the motor target torque calculated therefrom and offset in time,
3. c. Shifting the target engine torque from a second half revolution of the actuating device by the determined phase offset, so that the target engine torque and the drive torque are substantially synchronous in time.

According to a further preferred further development of the invention, it can also be provided that after method step b. in a subsequent process step b1. the time profile of the drive torque of the first half revolution of the actuating device is stored in the control unit. In this way, the time profile of the drive torque of the first half revolution of the actuating device can be made available as a reference curve, which can be used for the subsequent pedaling impulses to calculate a manipulated variable for the motor target torque.

Furthermore, according to a likewise advantageous embodiment of the invention, it can be provided that from the second half revolution of the actuating device, the gradient of the current drive torque is compared with the gradient of the drive torque stored in the control unit and, if there is a deviation, a correspondingly adapted manipulated variable for a larger or smaller engine target torque is generated. Since the torque fluctuation that occurs during normal driving operation, for example due to the crank kinematics of the actuating device and human physiology, is qualitatively known, it is particularly preferred to be able to use the increase in a drive torque applied to the actuating device after the first half rotation to calculate in advance whether the corresponding pedaling impulse will be stronger, the same or lower and the manipulated variable for the motor target torque can be adjusted accordingly, so that the driver can feel the drive thrust without phase shift and in terms of quantity in good agreement with the actually desired by the pedaling impulse, but "too late" calculated manipulated variable for the engine target torque.

According to a further particularly preferred embodiment of the invention, it can be provided that from the second half rotation of the actuating device, the pedaling of the actuating device is monitored in such a way that if there is a predefined period of time in which the actuating device has not been pedaled, the method is reset and repeated again with process step a. begins.

Furthermore, the object of the invention can be achieved by a computer program product stored on a machine-readable carrier, or computer data signal embodied by an electromagnetic wave, with program code suitable for carrying out the method according to any one of claims 3-7.

Finally, the object of the invention is also achieved by a control unit for controlling an electric drive system for a vehicle that can be operated with muscle power, comprising a processor and a memory containing computer program code, the memory and the computer program code being configured with the processor, the control unit to carry out a method according to one of Claims 3-7.

The invention will be explained in more detail below with reference to figures without restricting the general inventive idea.

• 1 ein schematisches Blockschaltbild eines elektrischen Antriebssystems 1 für ein mit Muskelkraft betreibbares Fahrzeug,
• 2 zeitlicher Verlauf des Antriebsdrehmoments und des Motor-Soll-Moments nach dem Stand der Technik, und
• 3 zeitlicher Verlauf des Antriebsdrehmoments und des Motor-Soll-Moments gemäß der Erfindung.

Show it:

• 1 a schematic block diagram of an electric drive system 1 for a vehicle that can be operated with muscle power,
• 2 Time course of the drive torque and the engine target torque according to the prior art, and
• 3 Time course of the drive torque and the motor target torque according to the invention.

The figure shows 1 an electrical drive system 1 for a vehicle 100 that can be operated with muscle power, comprising a first electrical machine 2 that can be operated as a motor, which acts on a drive wheel 101 of the vehicle 100 for the purpose of driving, and a second electrical machine 3 that can be operated as a generator, which is set up to convert mechanical energy introduced by a driver of vehicle 100 via a pedal-operated actuating device 15 into electrical energy. The drive system 1 shown is designed as a chainless drive system, i.e. there is no mechanical transmission of force and/or torque between the actuating device 15 and the electric machine 2 that can be operated as a motor.

The drive system 1 also has an energy storage device 4, such as a chargeable electric battery, for storing and delivering electrical energy, the energy storage device 4 for delivering and/or receiving electrical energy being electrically connected to the control/regulation of the first electrical machine 2 and the controller / Regulation of the second electrical machine 3 is connected.

Furthermore, the drive system 1 has a central control unit 5 for activating the first electric machine 3 and for activating the second electric machine 2 in such a way that a muscle-induced rotation of the actuating device 15 can generate an electrically induced rotation of the drive wheel 101 by using the by muscle power acting on the actuating device 15 drive torque 7, a manipulated variable 9 for a motor target torque 8 is calculated.

The control unit 5 for controlling the electric drive system 1 for a vehicle 100 that can be operated with muscle power comprises a processor 21 and a memory 22, which contains a computer program code, the memory 22 and the computer program code being configured with the processor 21, the control unit 5 for to initiate the procedure described below.

This calculation of the manipulated variable 9, caused by the duration of the calculation, leads to a phase offset 6 between the drive torque 7 applied by muscle power and the motor target torque 8 calculated from it and offset in time, that via which the first electric machine 2 is connected to the Drive wheel 101 is transmitted. This is in the 2 shown, in which the corresponding torque curves versus time (T) or a rotational angle position (a) of the actuating device 15 are shown. It can be seen that the two peaks of the drive torque 7, which are applied by the maximum muscle power-induced drive torque 7, for example on a left and a right pedal of an actuating device 15. These torque curves 7.8 are shown in simplified form for the purpose of illustration. The electrically amplified engine setpoint torque 8 is always offset from the drive torque 7 by a period of time, which is referred to as phase offset 6 . This phase offset 6 can lead to a driving experience that a driver perceives as “unnatural” when pedaling.

The ones from the 1 Known control unit 5 is now set up to determine a first complete revolution 11 of actuating device 15 connected to second electrical machine 3 . This is based on the 3 explained in more detail.

If the first complete revolution 11 has been determined, the phase offset 6 occurring within the first complete revolution of the actuating device 15 between the drive torque 7 applied to the second electric machine 3 by muscle power and the motor setpoint torque 8 calculated therefrom and offset in time is determined.

In principle, it is of course also conceivable that the phase offset 6 is already stored in the control unit 5 and is not initially determined at the beginning of pedaling, since the phase offset 6 is usually a constant value which essentially depends on the processor performance of the control unit 5 and depend on the complexity of the control or regulation algorithm. In this respect, if the phase offset 6 is already known, the method can already be used during a first complete rotation of the actuating device 15 .

From the second complete revolution of the actuating device 15, the engine target rotation Torque 8 shifted by the determined phase offset 6, ie advanced in time, so that the motor target torque 8 and the drive torque 7 are substantially synchronous in time, as is shown in the right-hand part of the diagram 3 is shown.

For this purpose, the time course of the drive torque 7 of the first complete revolution 11 of the actuating device 15 is stored in the control unit 5 . From the second complete revolution of the actuating device 15, the gradient of the respective current drive torque 7 is then compared with the gradient of the drive torque 7 stored in the control unit 5 and, if there is a deviation, a correspondingly adapted manipulated variable 9 for a larger or smaller engine setpoint torque 8 generated. This is continuously monitored along the rising edge of the current drive torque 7 and is regulated or controlled in such a way that the apex of the drive torque curve and the motor target torque curve are passed synchronously in terms of time.

From the second complete revolution of the actuating device 15, the pedaling of the actuating device 15 is monitored in such a way that if there is a predefined period of time in which the actuating device 15 has not been pedaled, the method is reset and once a first complete revolution 11 has been determined, the second electrical machine 3 associated actuating device 15 begins.

The invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered as limiting but as illustrative. The following patent claims are to be understood in such a way that a mentioned feature is present in at least one embodiment of the invention. This does not exclude the presence of other features. If the patent claims and the above description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a ranking.

Reference List

1

drive system

2

electric machine

3

electric machine

4

energy storage device

5

control unit

6

phase shift

7

drive torque

8th

Motor Target Torque

9

manipulated variable

10

vehicle

11

revolution

15

actuating device

21

processor

22

Storage

100

vehicle

101

drive wheel

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 102013012208 A1 [0004]

Claims (9)

Electrical drive system (1) for a vehicle (100) that can be operated with muscle power, comprising • a first electrical machine (2) that can be operated at least as a motor and acts on a drive wheel (101) of the vehicle (100) for the purpose of driving, • a second electrical machine (3) that can be operated at least as a generator and is set up to convert mechanical energy introduced by a driver of the vehicle (100) via a pedal-operated actuating device (15) into electrical energy, • an energy storage device (4) for storing and for Output of electrical energy, and • a central control unit (5) for controlling the first electric machine (3) and for controlling the second electric machine (2) in such a way that a muscle-powered rotation of the actuating device (15) causes an electrically-induced rotation of the Drive wheel (101) can be generated by using muscle power acting on the actuating device (15) to produce A drive torque (7) a manipulated variable (9) for a motor target torque (8) is calculated, characterized in that the control unit (5) is further set up, • at least half a revolution (11) with the second electrical machine ( 3) to determine the connected actuating device (15) and • to provide the phase offset (6) between the drive torque (7) applied to the second electrical machine (3) by muscle power and the motor setpoint torque (8) calculated therefrom and offset in time, where • the target motor torque (8) is shifted by the phase offset (6), so that the target motor torque (8) and the drive torque (7) are substantially synchronous in time. Electric drive system (1) according to claim 1 , characterized in that the control unit (5) is further set up • to determine a first half revolution (11) of the actuating device (15) connected to the second electrical machine (3) and • within the first half revolution (11) of the actuating device (15) to determine the phase offset (6) between the drive torque (7) applied to the second electrical machine (3) by muscle power and the motor target torque (8) calculated therefrom and offset in time, where • from a second half revolution the actuating device (15), the target motor torque (8) is shifted by the determined phase offset (6), so that the target motor torque (8) and the drive torque (7) are essentially synchronous in time. Method for controlling an electric drive system (1) for a vehicle (100) that can be operated with muscle power, comprising, • a first electrical machine (2) which can be operated at least as a motor and which acts on a drive wheel (101) of the vehicle (100) for the purpose of driving, • a second electrical machine (3) that can be operated at least as a generator and is set up to convert mechanical energy introduced by a driver of the vehicle (100) via a pedal-operated actuating device (15) into electrical energy, • an energy storage device (4) for storing and delivering electrical energy, and • a central control unit (5) for controlling the first electrical machine (3) and for controlling the second electrical machine (2) in such a way that the drive wheel (101) can be rotated electrically by means of a muscle-powered rotation of the actuating device (15). by calculating a manipulated variable (9) for a target engine torque (8) from the drive torque (7) acting on the actuating device (15) by muscle power, comprising the following steps: a. Determining at least half a revolution (11) of the actuating device (15) connected to the second electrical machine (3), b. Determination of a phase offset (6) between the drive torque (7) applied to the second electrical machine (3) by muscle power and the motor setpoint torque (8) calculated therefrom and offset in time, c. Shifting the motor target torque (8) to the determined phase offset (6), so that the motor target torque (8) and the drive torque (7) are substantially synchronous in time. procedure after claim 3 , characterized in that the method steps ac are modified as follows: a. Determining a first half revolution (11) of the actuating device (15) connected to the second electrical machine (3), b. Determination of a phase offset (6) within the first half rotation (11) of the actuating device (15) between the drive torque (7) applied to the second electrical machine (3) by muscle power and the motor target torque (8 ), c. Shifting the motor target torque (8) from a second half revolution of the actuating device (15) to the determined phase offset (6), so that the motor target torque (8) and the drive torque (7) run substantially synchronously over time. procedure after claim 3 or 4 , characterized in that after process step b. in a subsequent method step b1. the time profile of the drive torque (7) of the first half revolution (11) of the actuating device (15) is stored in the control unit (5). procedure after claim 3 , 4 or 5, characterized in that from the second half revolution of the actuating device (15) the slope of the current drive torque (7) is compared with the slope of the drive torque (7) stored in the control unit (5) and if there is a deviation a correspondingly adapted manipulated variable (9) for a larger or smaller engine target torque (8) is generated. Procedure according to one of claims 3 - 6 , characterized in that from the second half revolution of the actuating device (15) the pedaling of the actuating device (15) is monitored in such a way that if there is a predefined period of time in which the actuating device (15) was not pedaled, the method is reset and again with the method step a. begins. Computer program product stored on a machine-readable medium, or computer data signal embodied by an electromagnetic wave, with program code suitable for carrying out the method according to one of claims 3 - 7 . Control unit (5) for controlling an electric drive system (1) for a human-powered vehicle (100), comprising a processor (21) and a memory (22) containing computer program code, the memory (22) and the computer program code being configured are, with the processor (21), the control unit (5) for carrying out a method according to one of claims 3 - 7 to cause.

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