CN111448380A - Method and device for determining the direction of rotation of a crankshaft of an internal combustion engine - Google Patents

Method and device for determining the direction of rotation of a crankshaft of an internal combustion engine Download PDF

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Publication number
CN111448380A
CN111448380A CN201880080235.2A CN201880080235A CN111448380A CN 111448380 A CN111448380 A CN 111448380A CN 201880080235 A CN201880080235 A CN 201880080235A CN 111448380 A CN111448380 A CN 111448380A
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signal
phase
sum
pulse
determining
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CN201880080235.2A
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CN111448380B (en
Inventor
V.K.马蒂瓦拉维拉巴萨帕
B.雷内克
J.穆勒
W.菲舍尔
A.里奇
S.葛罗德
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Robert Bosch GmbH
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Robert Bosch GmbH
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    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/009Electrical control of supply of combustible mixture or its constituents using means for generating position or synchronisation signals
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D41/00Electrical control of supply of combustible mixture or its constituents
    • F02D41/0097Electrical control of supply of combustible mixture or its constituents using means for generating speed signals
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/246Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains by varying the duration of individual pulses
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P13/00Indicating or recording presence, absence, or direction, of movement
    • G01P13/02Indicating direction only, e.g. by weather vane
    • G01P13/04Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/42Devices characterised by the use of electric or magnetic means
    • G01P3/44Devices characterised by the use of electric or magnetic means for measuring angular speed
    • G01P3/48Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
    • GPHYSICS
    • G01MEASURING; TESTING
    • G01PMEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P3/00Measuring linear or angular speed; Measuring differences of linear or angular speeds
    • G01P3/42Devices characterised by the use of electric or magnetic means
    • G01P3/44Devices characterised by the use of electric or magnetic means for measuring angular speed
    • G01P3/48Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage
    • G01P3/481Devices characterised by the use of electric or magnetic means for measuring angular speed by measuring frequency of generated current or voltage of pulse signals
    • G01P3/489Digital circuits therefor
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D2200/00Input parameters for engine control
    • F02D2200/02Input parameters for engine control the parameters being related to the engine
    • F02D2200/10Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101Engine speed
    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02DCONTROLLING COMBUSTION ENGINES
    • F02D29/00Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
    • F02D29/06Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving electric generators
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P9/00Arrangements for controlling electric generators for the purpose of obtaining a desired output
    • H02P9/48Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)

Abstract

The invention relates to a method for determining a rotational variable, in particular a rotational direction (α), of a shaft (17), in particular a crankshaft (17') of an internal combustion engine (112)+、α) The internal combustion engine is coupled directly or by transmission to an electric machine (30) comprising a rotor (32) and a stator having at least two windingsA stator (33) of a group (U, V, W), from which at least one phase signal (U) is derived in each caseU、UV、UW、IU、IV、IW) Wherein the phase signal (U)U、UV、UW、IU、IV、IW) Respectively have a rising edge (Fl)Uu、FlVu、FlWu) Falling edge (Fl)Ud、FlVd、FlWd) And/or zero crossing (Fl)U0、FlV0、FlW0) Wherein a plurality of phase signals (U) comprising the motor (30) are generatedU、UV、UW、IU、IV、IW) Sum signal (U)Sum) So that at said sum signal (U)Sum) Respectively giving said rising edge (Fl)Uu、FlVu、FlWu) Falling edge (Fl)Ud、FlVd、FlWd) And/or zero crossing (Fl)U0、FlV0、FlW0) Assigning a characteristic pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Wherein said pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Is used to determine the rotational speed (n) and the rotational angle position (theta ) of the rotor (32)1) Or direction of rotation (α)+、α). The invention also relates to: for transmitting a plurality of phase signals (U)U、UV、UW、IU、IV、IW) Generating a sum signal (U)Sum) The summed signal is used to determine the rotational speed (n) of the shaft (17); a corresponding computing unit is set up for carrying out the method; and a computer program for performing the method.

Description

Method and device for determining the direction of rotation of a crankshaft of an internal combustion engine
Technical Field
The invention relates to a method and a device for determining a rotational variable, in particular a rotational direction, of a shaft, in particular a crankshaft of an internal combustion engine, which is directly or drivingly coupled to an electric machine, which comprises a rotor and a stator having at least two phase windings, from which at least one phase signal is derived in each case.
Background
The rotational speed of the crankshaft of an internal combustion engine is an important input variable for various functions of an electronic engine control system. In order to determine the rotational speed, markings may be provided on the body that rotates together with the crankshaft of the internal combustion engine at the same angular distance. The marking due to the rotation of the crankshaft can be detected by the sensor and forwarded as an electrical signal to the evaluation electronics.
The electronic device determines a signal registered for the marker for this purpose or measures the time difference between the two markers for the respective rotational angle position of the crankshaft, and can determine the angular velocity and the rotational speed on the basis of the known angular distance of the two markers from one another. In the case of motor vehicles, in particular motorcycles, motorbikes or motorbikes, these markings can be provided, for example, by the teeth of metal gears of a so-called sensor wheel, preferably of metal gears made of ferromagnetic material, which, due to their movement, cause a change in the magnetic field in the sensor. The absence of several teeth can be used as a reference mark for identifying the absolute position. In the case of passenger vehicles (Pkw), 60-2 teeth (60 teeth evenly distributed, with 2 teeth being left empty as reference symbols) are mostly used, while in the case of motorcycles or motorbikes, for example, 36-2, 24-2 teeth are also used. In the case of this indirect principle of the determination of the rotational speed of the crankshaft or of the rotational angle position of the crankshaft, the resolution of the rotational speed signal or the absolute detection of the rotational angle position is determined by the number of teeth and by a reliable identification of the reference markings.
In the case of any modern vehicle with an internal combustion engine, an electric generator is built, which is driven by the rotation of the crankshaft. The generator provides an electrical signal and is used to supply the vehicle with electrical energy and to charge the vehicle battery pack. The intended operation of the vehicle without the generator is not possible or only possible for a short time.
The use of an electrical output variable of an electric machine (generator) driven by the crankshaft is used for speed determination, for example, in EP 0664887B 1. For this purpose, the phase of the generator to which the pulsed dc voltage is attached is provided as a reference. In the case of a rotational speed determination using a plurality of phases, the respective signals of the phases are usually detected and separately forwarded to an evaluation unit, which determines the rotational speed of the generator from the signals.
It would therefore be desirable to specify a way of determining a rotational variable, in particular a rotational direction, which is simplified even further depending on the phase signal of the electric machine and which makes it possible to obtain at least the rotor of the electric machine or the crankshaft of the internal combustion engine, which can be used for controlling the rotational direction of the internal combustion engine, even more simply and, if appropriate, with even better accuracy, even without the use of additional components.
Disclosure of Invention
According to the invention, a method having the features of claim 1 and an apparatus having the features of claim 10 are proposed. Advantageous embodiments are the subject matter of the dependent claims and the subsequent description.
THE ADVANTAGES OF THE PRESENT INVENTION
The invention relates to a method for determining a rotational variable of a shaft, in particular of a crankshaft of an internal combustion engine, which is directly or drivingly coupled to an electric machine, which comprises a rotor and a stator having at least two phase windings, from which at least one phase signal is derived in each case, wherein the phase signals each have a rising edge, a falling edge and/or a zero crossing, wherein a summation signal comprising a plurality of phase signals of the electric machine is generated such that in the summation signal, in each case characteristic pulses are assigned to the rising edges, falling edges and/or zero crossings, wherein the variable is used to determine the rotational variable of the rotor of the electric machine. In this case, the rotational variable includes, in particular, the direction of rotation of a shaft, preferably a rotor shaft, wherein the rotor shaft is fixedly or drivingly coupled or coupleable to a crankshaft of the internal combustion engine. If the respective rotational variable of the rotor shaft is known, the corresponding rotational variable of the crankshaft of the internal combustion engine can therefore be directly inferred.
Within the scope of the method, the sum signal is generated from phase signals of at least two phases of the electric machine. The generation of the summation signal for determining the rotational variable, in particular the rotational direction, is particularly advantageous, since the summation signal can be forwarded to an evaluation unit, in particular to a control device, by means of a single signal line, in order to derive therefrom, depending on the summation signal, the respective rotational information on which the rotational variable of the generator phase is based from the signal of the respective generator phase, whereby the rotational direction of the shaft can be determined not only particularly simply and on the basis of a particularly simple signal line infrastructure, but also with the usual accuracy. This is caused in particular by: in the sum signal, characteristic pulses are assigned to the rising edges, falling edges and/or zero crossings of the respective phase signal, wherein the respective rotation variable can be derived from the signals of the respective pulses in the sum signal.
This method is particularly advantageous since in the prior art, the signals of the respective phase are usually each forwarded to an evaluation unit by means of a signal line assigned to the respective phase, in order to be evaluated there. This is correspondingly costly and cost sensitive.
Preferred within the scope of the invention are: at least one value of at least one of the pulses associated with a rising edge of the phase signal, with a falling edge of the phase signal and/or with a zero crossing of the phase signal is used for transmitting the corresponding pulse in the sum signal, whereby the absolute position over time of these rising edges, falling edges and/or zero crossings and their relative spacing from each other can be determined and from this especially the direction of rotation of the shaft can be determined. This embodiment is particularly advantageous because not only the rising edges, falling edges and zero crossings of the phase signals, which are correspondingly converted into pulses within the sum signal by the previously described coding, can be detected particularly simply and precisely, which results in a correspondingly reliable and precise determination of the aforementioned rotation variable of the shaft. The phase signal may be the original signal of the stator phase. However, correspondingly electronically processed phase signals may also be used.
In a further preferred embodiment, in the sum signal, the first pulse is generated by coding the falling edge of the respective phase signal and the further pulses are generated by coding the rising edge of the respective phase signal. By a correspondingly different selection of the pulses, at least one criterion is given in order to enable rising and falling edges to be correspondingly distinguished in the sum signal in the form in which they are converted into pulses. It should be noted again that: the position over time of the respective edges and their type, i.e. rising and/or falling edges, are correspondingly converted into pulses in the sum signal and can be distinguished.
In a further preferred embodiment of the method, the pulses assigned to the first edge type having a rising edge or a falling or falling edge have a constant first pulse width, while the pulses assigned to the respectively other edge type have a further pulse width which is constant for the respective phase signal but differs with respect to the respectively other edge type and/or the respectively other phase. This embodiment is advantageous because in this way, edges of this type can be detected in the sum signal in a correspondingly simple manner by selecting a constant pulse width for one of the edge types. By this, the number of different pulse widths can be reduced without information loss. This assignment can be simplified as a function of the design of the evaluation algorithm for the sum signal for assigning the individual pulses to their respective edge type and phase signal. Correspondingly, the characteristic pulse width can be selected for the respective edge type or edge type and/or the respective phase, whereby the respective edge type and the phase associated therewith can be unambiguously assigned.
This is provided within the scope of a preferred embodiment, in particular, by the following: a first edge type is asserted by determining that there is a first pulse width in the summed signal and a corresponding other edge type is asserted by determining that there is one of the other pulse widths in the summed signal.
Within the scope of a further preferred embodiment of the method, the rotational speed of the rotor of the electric machine can be determined from the sum signal by determining at least one time difference between two pulses corresponding to the same edge type (rising or falling edge). Preferably, the same type of edges are used, which can be attributed to one of the phases. As already mentioned, a particularly simple way of determining the rotational speed of the electric machine as a function of the relative spacing of the pulses from one another exists if the same pulse duration is selected for one of the edge types independently of one another. In a further preferred embodiment, the rotational speed is determined on the basis of two adjacent pulses, preferably immediately adjacent pulses.
In a further preferred embodiment of the method, the first direction of rotation is deduced by determining at least one first time sequence of pulses or a further direction of rotation of the rotor, which is different from the first direction of rotation, is deduced by determining at least one further time sequence of pulses. The respective edges within the phase signal are correspondingly determined over time depending on the specified motor parameters, such as the arrangement of pole pairs within the motor, and other parameters. By means of an analysis of the sequence of corresponding pulses in their chronological order, it is therefore possible to deduce the direction of rotation of the rotor of the electric machine. For this purpose, the edges from the respective phase signal and the edge types (rising or falling) of these edges are each encoded with different pulse widths in the sum signal in order to be able to distinguish these edges from these edge types. Thus, from the corresponding sequence of rising and falling edges from the respective phase signals, the direction of rotation of the rotor within the motor can be deduced based on the summed signal.
The respective pulse can also be determined by determining the pulse width, and the rotational angle position of the rotor of the electric machine can be determined from the respective pulse using the characteristics of the electric machine. Thus, by determining the pulse width, falling and rising edges can be unambiguously deduced from the corresponding phase signals, as has already been described above. Since, as has also been described, the individual edges are associated with the spatial arrangement of the motor parameters, such as the pole pairs within the motor, by determining the respective edge and associating it with these motor parameters, it is possible to deduce at least the corresponding angular increment within which the rotor moves linearly at the time of the detection of the respective edge within the sum signal. From this, the rotational angle position of the rotor can be correspondingly deduced.
The angular position of the rotor can be determined further using the rotational speed value between two adjacent pulses and at least one time interval between the following position and at least one of the pulses. The aforementioned position is an arbitrary position over time within the sum signal for which the corresponding rotational angle position of the rotor is to be determined. This can be achieved in particular when the electric machine is running, but also when the internal combustion engine driving the electric machine is deactivated. The latter case is particularly suitable for determining the rest position of the rotor of the electrical machine. As already described above, by using the pulses associated with the respective edges of the phases and further using the motor parameters, an angular increment can be deduced within which the rotor lies linearly at the time of the positioning. By further using the rotational speed values, which describe the change over time of the angular increment, and the corresponding time intervals of the positions and the corresponding pulses, it is possible to determine the positions within the angular increment even more precisely.
The invention also relates to a device for generating a sum signal from a plurality of phase signals, which sum signal can be used to determine a rotational variable, in particular a rotational direction, of a shaft, in particular a crankshaft of an internal combustion engine, which is coupled directly or in a driving manner to an electric machine, which comprises a rotor and a stator having at least two phase windings, from which at least one phase signal can be derived in each case, which phase signal has a rising edge, a falling edge and/or a zero crossing. In this case, the device has at least two inputs via which the phase signals are respectively conducted to a coding unit, wherein the coding unit combines the individual phase signals into a sum signal and codes at least one of the phase signals in such a way that a characteristic pulse is respectively assigned to a rising edge and/or a falling edge of the at least one phase signal in the sum signal, wherein the coding unit outputs the sum signal to an output for determining the rotation variable. Similar to the method according to the invention, determining the direction of rotation of the rotor from the summation signal can be carried out particularly simply, since only one data line is required for forwarding the summation signal to the evaluation device. The characterizing variables from the phase signals required for determining the respective rotation variable, i.e. the respective edges of the respective phase signals, are likewise converted, as already described above, into corresponding pulses within the sum signal, it being possible to analyze these pulses from the sum signal without losing information.
By means of the encoding unit, therefore, the edges within the respective phase signal are encoded in the summation signal in such a way that they are converted into pulses which can be directly assigned to these edges, whereby a particularly precise determination of the rotation variable can be ensured with a significant simplification of the analysis infrastructure.
In a further preferred embodiment of the device, the coding unit has at least one time lag element which can be assigned to at least one phase of the electric machine and which applies a characteristic to at least one phase signal. The time-lag link is used for: in particular, a combination of a plurality of exclusive-or gates (Xor) each loads at least one phase signal with a characteristic feature. This is caused in particular by: by means of a corresponding design of the time-lag elements, the pulses respectively assigned to the corresponding rising or falling edge of the phase signal are assigned a correspondingly characteristic pulse duration. By using different time lag elements for different phase signals, the respective phase signal can be loaded with characteristic properties depending on the respective used time lag element, so that, as already described above, the individual edge types from the respective phase signal can be loaded with in principle different properties, in particular in the form of different pulse durations.
It is also easy to understand that: it is also possible to assign in part the same pulse duration to one of the two edge types (rising or falling edge) from the characteristic features in the phase signals, in particular the respective phase signals, and to assign only the edges of the respectively other edge type of each phase signal a different pulse duration in order to make the two edge types distinguishable. Within the at least one time lag element, the selection of the pulse duration of the respective pulse is preferably brought about by means of at least one capacitor and/or at least one resistor. In this case, the respective time constant is given by a corresponding selection of the capacity of the resistor or capacitor. The signals from the respective coding units assigned to these phases are then correlated with one another, preferably by way of and (Und) gates, and a sum signal is formed.
In a further preferred embodiment, a trigger circuit is assigned to the coding unit, which trigger circuit generates a triggered phase signal, which is supplied to at least one of the inputs of the coding unit. The trigger circuit causes: the edges of the phase signal in the triggered phase signal are significantly more pronounced than in the input signal, which makes the identification of the edges and the corresponding temporally accurate conversion of these edges into pulses in the sum signal particularly simple to implement. The rotational variable, in particular the rotational direction of the rotor, can therefore also be determined more precisely from the sum signal, with a correspondingly higher temporal resolution in the azimuth direction.
In a preferred embodiment, the trigger circuit has a dead-time element with a resistor and a capacitor. Through a corresponding selection of the resistor and the capacitor, a forwarding of the triggered phase signal in the vicinity of the zero crossing in the time range of the phase signal can be correspondingly suppressed. This embodiment is particularly advantageous because disturbances, which can be separated or suppressed particularly effectively by such a circuit, can occur in the signal due to unbalanced states, in particular in the vicinity of the zero crossings of the phase voltages. In this case, the respective time constant is given by a corresponding selection of the capacity of the resistor or capacitor. In principle, it is easy to understand that: the exclusive-or (Xor) gate described previously can also be replaced by a corresponding other electronic circuit with similar functionality.
In a further preferred embodiment of the method, the rotation variable, in particular the direction of rotation of the shaft, is used for controlling the ignition and/or injection of fuel into the internal combustion engine, in particular into at least one cylinder of the internal combustion engine. The detection and processing of the phase signals of the electric machine, in particular by the engine control device, can be used in a corresponding manner in a control device of the internal combustion engine for controlling the ignition or for controlling the torque of the internal combustion engine. The rest position of the rotor of the electric machine and thus also of the crankshaft of the internal combustion engine can be correspondingly detected. Corresponding control in a higher-level control device, in particular an engine control device, is particularly preferred, since this control device is already present and can use system resources accordingly, so that the functionality for detecting the direction of rotation and the functionality for controlling the internal combustion engine can be combined in one control device. In this way, a synergistic effect is obtained with respect to rules and communication infrastructure that can be shared. Further advantages are also obtained since the summation signal is used for data exchange with the control device, since only one data line is required for this purpose.
For this purpose, the computing unit used, which is preferably designed as an engine control device for an internal combustion engine, has a correspondingly integrated circuit and/or a computer program stored on a memory, which is/are set up to carry out the method steps described above.
It is advantageous to implement the method or to provide an integrated circuit, in particular an ASIC (application specific integrated circuit), in the form of a computer program which is preferably stored in the form of software on a data carrier, in particular a memory, and is available in the computing unit for implementation of the method, since this results in particularly low costs, in particular when the control device to be implemented is also used for other tasks and thus always already exists. Data carriers suitable for providing the computer program are, in particular, magnetic memories, optical memories and electronic memories, as are often known from the prior art.
Further advantages and embodiments of the invention emerge from the description and the accompanying drawings.
Drawings
Fig. 1 shows a schematic representation of a sensor wheel according to the prior art with sensors, in particular for rotational speed determination;
fig. 2a to 2c show schematic diagrams (a, b) of an electric machine coupled to an internal combustion engine and the associated signal waveforms (c);
fig. 3 schematically shows an electric machine with corresponding associated phase signals;
fig. 4a and 4b schematically show an evaluation circuit (a) for phase voltages and phase signals (b) associated with the phase voltages according to an embodiment;
fig. 5a to 5c schematically show an evaluation circuit (a) for phase voltages, phase signals (b) associated with the phase voltages and typical signal waveforms (c) at the individual components of the evaluation circuit according to a further embodiment;
fig. 6a and 6b show phase signals (a) of the phases of a three-phase motor obtained from voltage waveforms and an enlarged view (b) of these signals;
fig. 7a and 7b schematically show a circuit (a) for generating a sum signal from a plurality of phase signals and a waveform sum signal (b) over time for each phase signal;
fig. 8a to 8d schematically show waveforms (a) over time of a summation signal according to which a determination of the direction of rotation of the shaft is elucidated; a waveform (b) over time is schematically shown, from which a summation signal is set forth for determining the rotational angle position of the shaft according to the first embodiment; a waveform (c) over time is schematically shown, from which a summation signal is set forth for determining the rotational angle position of the shaft according to a further embodiment; a schematic flow chart (d) illustrating a method according to one embodiment is shown.
Detailed Description
Fig. 1 schematically shows a sensor wheel 20 of a rotational speed sensor G and an associated inductive sensor 10, as it is used in the prior art for determining the rotational speed or for approximately determining the rotational angle position of a crankshaft. In this case, the sensor wheel 20 is fixedly connected to the crankshaft of the internal combustion engine and the sensor 10 is mounted in a stationary manner in a suitable location.
The sensor wheel 20, typically a sensor wheel 20 made of ferromagnetic material, has teeth 22 which are arranged on the outside with a space 21 between two teeth 22. At a point on this outer side, the sensor wheel 20 has a recess 23 over the length of a predetermined number of teeth. This recess 23 serves as a reference mark for identifying the absolute position of the sensor wheel 20.
The sensor 10 has a bar magnet 11 on which a soft magnetic pole pin 12 is mounted. The soft pole pin 12 is in turn surrounded by an induction coil 13. As the sensor wheel rotates, the teeth 22 and the gaps between two respective teeth alternately pass the induction coil 13 of the sensor 10. Since the sensor wheel and therefore also the teeth 22 consist of ferromagnetic material, a signal is induced in the coil during rotation, with which a distinction can be made between the teeth 22 and the recesses.
By correlating the time difference between two teeth with the angle enclosed by the two teeth, the angular speed or rotational speed of the crankshaft and, in addition, the corresponding angular position of the crankshaft can be approximated.
At the gap 23, the signal induced in the induction coil has a different waveform than at the teeth 22 that would otherwise alternate with the gap.
In FIG. 2a, there is depictedAn internal combustion engine 112 to which the electric machine 30 is directly or via a transmission coupling, wherein the electric machine 30 is driven by a crankshaft 17' of the internal combustion engine 112. Thus, the rotational speed n of the motor 30GenAnd the rotational speed n of the crankshaft 17BKMAnd the angular position θ of the rotor of the motor 301And the rotational angle position theta of the crankshaft 17' have a fixed relationship with one another, the electric machine 30 is also assigned a charging controller L R, which supplies energy to the battery B within the on-board electrical system 110 depending on the still remaining capacity of the battery B.
A computing unit, in particular an engine control device 122, is also provided, which exchanges data with the electric machine 30 or with the internal combustion engine 112 via a communication connection 124 and is set up to correspondingly control the internal combustion engine 112 and the electric machine 30. External sensor data, e.g. for the inductive detection of the speed n of the internal combustion engine 112BKMOr preferably the rotational speed (n) of an electric machine 30 fixedly coupled to the internal combustion engineGen) The sensor data of the sensor 10 can likewise be included in the communication link 124, wherein the engine control device 122 forwards control signals for controlling the internal combustion engine 112 to the internal combustion engine on the basis of the sensor data of the electric machine 30 and/or further sensor data of the sensor 10. Rotor 32 and direction of rotation a of its shaft 17+、a-Is also described, wherein a+Indicates a positive rotation in the preferential direction of the internal combustion engine 112 and a-Indicating reverse rotation in the opposite direction. The rotational angle position theta of the crankshaft 17' or the rotational angle position theta of the rotor 32 are also specified1
In fig. 2b, the motor 30 is again schematically shown in an enlarged form. The motor 30 has: a rotor 32 with a shaft 17, the rotor having field windings; and a stator 33 having stator windings U, V, W. This therefore relates to separately excited electrical machines, as are customary in motor vehicles in particular. However, especially for motor-driven vehicles, especially in the case of small and lightweight motor-driven vehicles, motors with permanent magnets, that is to say permanent magnet motors, are mostly used. Within the scope of the invention, it is in principle possible to use two types of electric machines, wherein in particular the method according to the invention does not depend on the use of a corresponding type of electric machine, for example a permanent magnet machine or a separately excited machine.
The electric machine 30 is designed as a three-phase generator, in which three phase voltage signals are induced, which are phase-shifted by 120 ° with respect to one another. Such three-phase generators are usually used as generators in modern motor vehicles and are suitable for carrying out the method according to the invention. Within the scope of the invention, in principle, all electric machines can be used, independently of their number of phases, wherein in particular the method according to the invention does not depend on the use of a corresponding type of electric machine.
The three phases of the three-phase generator 30 are represented by U, V, W. The voltages falling on these phases are rectified by means of rectifying elements in the form of a positive diode 34 and a negative diode 35. Therefore, the generator voltage UGAttached between the poles B + and B-, and the negative pole is grounded at the voltage of the generator. For example, a battery B or other electrical consumers within the vehicle electrical system 110 are supplied by such a three-phase generator 30.
Fig. 2c shows three graphs, which show the associated voltage waveforms with respect to the rotational angle of the rotor 32 of the electric machine 30. In the upper graph, the voltage waveform at phase U, V, W is recorded. It is generally easy to understand that: the numerical sum value ranges illustrated in this diagram and in the subsequent diagrams are merely exemplary and thus do not limit the invention in principle.
In the middle diagram, the generator voltage U is shownGThe generator voltage is formed by the envelope of the positive and negative half waves of the voltage waveform U, V, W.
Finally, in the lower diagram, the rectified generator voltage U is shownG-(see fig. 2 a) together with the generator voltage UG-Effective value of (U)GeffThe generator voltage is attached between B + and B-.
In fig. 3, the stator 33 with phase U, V, W from fig. 2b is schematically shown, together with a positive diode 34 and a negative diode 35. In principle, it is easy to understand that: the rectifier elements depicted here in the form of a positive diode 34 and a negative diode 35 in the case of active rectifiers can also be constructed as transistors, in particular MOSFETs (metal oxide semiconductor field effect transistors) (not shown). The nomenclature used hereinafter for the voltages and currents that occur is also shown.
Alternatively, UU、UV、UWThe phase voltages of associated phase U, V, W are shown, as they fall between the phase lines and the star point of stator 33. U shapeUV、UVW、UWUWhich represents the voltage between two phases or the associated phase lines of these two phases.
IU、IV、IWShowing phase currents from the corresponding phase line of phase U, V, W to the star point. I represents the total current of all phases after rectification.
Fig. 4 schematically shows a schematic representation of a phase voltage U for a first embodimentUAnd an evaluation circuit 80a in the form of a schmitt trigger, and a phase voltage U of a phase U of the electric motor 30U(upper diagram) and the triggered phase voltage U obtained by means of the evaluation circuit 80aUt. A so-called schmitt trigger 80a is schematically shown in fig. 4 a. By means of such an evaluation circuit 80a, the phase voltage U is adapted to the respective phase voltage in the present caseUInput signal U ofI1Generating an output signal U obtained from the analysis circuit 80aO1Triggered phase voltage U as it is according to the lower diagram of fig. 4b)UtAs shown. The dashed horizontal line (see fig. 4 a) illustrated in the upper diagram correspondingly illustrates the switching threshold of the evaluation circuit 80 a.
Resistor R in the feedback branch of operational amplifier O1aAnd R2aResulting in a current-dependent output voltage U at the outputO1Of the switching threshold. Thus, by specifying the respective switching thresholds, the characteristics shown in the signal waveform can be realized and ensured so that signal noise in the vicinity of the acoustic point does not cause a change in the output level of the operational amplifier O. By means of the evaluation circuit, a triggered phase signal U can be generated which can be evaluated in a correspondingly simple mannerUtAccording to the beliefThe time intervals of the steep edges of the sign and respectively adjacent edges F L may determine the rotational speed of the motor 30.
Fig. 5 shows a further embodiment of an evaluation circuit 80b, by means of which the phase voltage U is assigned to the current case as an exampleUInput signal U ofI2To generate an output signal UO2The output signal in the present case corresponds to the triggered phase voltage UUt. Phase voltage UUtShown in the lower diagram of fig. 5 b). It is easy to understand that: also having other phase voltages UU、UV、UWAttached to the input end UI2The other phase voltages may result in the output terminal UO2Or UO2U、UO2V、UO2WUpper pair of triggered phase voltages UUt、UVt、UWtTo this end, see in particular fig. 6 and 7.
The evaluation circuit 80B has blocking means B for the purpose of registering the corresponding phase signal UU、UV、UWFiltering over time to perform noise suppression. In this case, the blocking means B are followed by at least one operational amplifier O, the phase signal UU、UV、UWIs attached to the input terminal O of the operational amplifierinThe above. The blocking device B has: a time-lag element T whose adjustable time-lag defines the time constant of the filtering over time; two switches F1And F2(ii) a And an inverter stage I. The time-lag link T has a resistance R1cAnd a capacitor C1cThe capacitor is charged with the current flowing through the output of the operational amplifier O. At the output U of the switching analysis circuito2Then, a first switch F, which is preferably designed in the form of an R/S flip-flop (Flipflop), is connected to the first input signal via a time-lag element T1In combination with switch F1Generates a pulse signal having a positive output voltage (High-L ev, High) with respect to a static voltage (low level (L ow-L ev), L ow), where the rising edge of the pulse signal and the signal O are at a High level (High-L ev, High)outIs simultaneously present at the output of the operational amplifier O. PulseThe subsequent falling edge of the burst occurs after the skew of the skew element T. In parallel, the output signal O of the operational amplifier O is generated by the inverter stage IoutThe inverted signal of (1). The inverted signal is sent to a second switch F which is preferably constructed in the form of an R/S flip-flop2And a pulse signal is sent to a Reset (Reset) input R. In this case, the switch F2 passes a first edge of the inverted signal to the output Uo2And then prevents the output from switching again as soon as the High level of the pulse signal (High-L evel) is attached or the output signal itself already has a High level.
Thereby, at the input end O of the operational amplifier OinNoise in the range of the falling edge of the upper band at the output Uo2The above is suppressed by: as long as there is no high level at the reset input R, the switch F2The output cannot be switched again. For the input terminal O of the operational amplifierinOn the rising edge of switch F2Has a switch F on the reset input terminal R1Pulse of the pulse signal. The pulse signal results in: switch F2 will output terminal Uo2Set to low level (L ow) at input OinPossible noise in the range of the rising edge above is suppressed by the switch F being held back as long as a High level (High-L evel) is attached to the reset input R2The output terminal U cannot be put againo2Set to a high level (Hgh). Therefore, during the pulse length, the output terminal U cannot be realizedo2And possible noise is suppressed. The characteristic time constant for this noise suppression is determined by the pair resistance R1cAnd a capacitor C1cTo the corresponding selection.
By using the blocking means B, the corresponding noise influence can be suppressed, as it is in the upper diagram in fig. 5B in the time range or duration Z0As shown near the inner zero line (each characterized by a circle). This results in a triggered phase signal UUt、UVt、UWtThe signal quality of (2) is improved. In fig. 5c), the resistors at the output of the operational amplifier O are shownR or capacitor C, in inverting stage I or Flip-Flop (Flip-Flop) F1Or F2Typical signal waveforms of (1).
It is advantageous in terms of this circuit with respect to the schmitt trigger solution (see fig. 3): detects the phase signal UU、UV、UWIn the form of a significantly more precise zero crossing of the input signal, wherein in the case of schmitt trigger 80a switching threshold for the phase signal is always required>0 (see fig. 3). By this, a phase signal U can be useduCharacteristic value W ofU0Or a correspondingly parallel arrangement of these trigger circuits may be used when there are multiple phase signals. These characteristic values WU0、WV0、WW0In particular, it can be used to determine the rotational speed n or the rotational angle position of the rotor 32 of the electric machine 30.
Here, the noise suppression is not realized by different thresholds, but by filtering over time by means of a time-lag element. The time-lag link switches the output U due to zero-crossing at the inputo2After which the output U is prevented for a first (short) timeo2Directly back (especially due to noise) is switched back. To output end Uo2May be triggered after the end of the dead time and the subsequent zero crossing, only then being the trigger switch F, which is placed after the operational amplifier O and the dead time element T1And/or F2Is wired and outputs a signal UO2With triggered phase signal UUtThe form of (d) is output.
Now, three phase voltage signals U with potential B-as reference are shown in FIG. 6a in three graphs versus timeU、UV、UWAs they occur in generators having an outer pole rotor with six permanent magnets. The illustration of an electrical machine 30 with three-phase stator windings 33 is to be seen merely as an example, wherein the method according to the invention can in principle also be implemented on generators with a correspondingly sufficient number of phases or permanent magnets or field coils, without limiting the generality. Also, instead of star-connection of stator coilsA delta connection or other connection may be selected.
In the case of an electric machine 30 with current output, the phase voltage U is the phase voltageU、UV、UWThe waveform of (a) is approximated to a rectangle at one level. This is indicated in particular by the following: due to the generator voltage, either the positive diode or the negative diode is conducting in the conducting direction, and thus either approximately 15-16 volts (battery charging voltage at 12V lead-acid battery and voltage across the positive diode) or negative 0.7-1 volts (voltage across the negative diode) is measured. The measured reference potentials are respectively grounded. Other reference potentials, such as star point of the stator, may also be selected. These reference potentials result in alternating signal waveforms, but do not change the analyzable information, the acquisition and analysis of this information.
In principle, phase signal (U)U、UV、UW、IU、IV、IW) May be obtained in different ways. For example, it is possible that: determining phase voltages (U) relative to each otherUV、UVW、UWU) (ii) a As long as the stator of the electric machine is star-connected with a measurable star point, the phase voltage is determined by the diodes of the connected rectifier relative to the output terminals (B +, B-) of the rectifier; taking into account the output voltage (U) of the branch with respect to the star pointU、UV、UW) (ii) a Or similarly analyze the phase currents.
In fig. 6b, the phase voltages U from fig. 6a processed by means of the triggering circuits 80a, b (see fig. 4 or 5 for this purpose) are plotted together in a diagramUt、UVt、UWt. In this case, a uniform phase shift is clearly visible. The term phase voltage UU、UV、UWOr the processed phase voltage UUt、UVt、UWtAre then used partially synonymously, since the phase voltage U is processedUt、UVt、UWtDirectly from the phase voltage UU、UV、UWAnd (5) obtaining the result.
At the rotation of the motor 30During one complete revolution of the sub 32, the voltage signal is repeated six times by six magnets, in particular permanent magnets, so-called pole pairs. Correspondingly, for each revolution of the rotor 32, each phase, i.e. each phase voltage UU、UV、UWSix falling edges F L occurDAnd six rising edges F LU(F L for the corresponding phase)UU、FLVU、FLWUAnd F LUD、FLVD、FLWD)。
These edges define angular segments, i.e. exactly the angular segments covered by the magnets in the radial direction of the stator, therefore, knowing the absolute reference point per revolution, it is possible to determine the corresponding edge F LUOr F LDFor example, the reference point is characterized by a reference magnet having a phase voltage UU、UV、UWTriggered waveform U of OR-phase voltageUt、UVt、UWtDifferent from other magnets.
Now, with suitable means, it is possible to identify not only the falling edge F L of the phase voltageDAnd may identify the rising edge F L of the phase voltageUFor example, for each phase voltage, a triggered waveform U of the phase voltage in the form of the TT L signal can be generated by means of the circuit shown in fig. 4 or 5Ut、UVt、UWtThe required trigger (see fig. 4 or 5) can either be integrated in the control device or in the control electronics, for example the control device, the control unit for the battery voltage and/or in the respective generator control unit in the case of an active rectifier, or can also be assigned externally to the generator control unit, the individual TT L signals can be combined in particular for the case of the use of the control device, in particular the engine control device 122 (see fig. 2 a), to form a sum signal USum(see fig. 7 and 8) and preferably combined via wires or by a preceding combined electronics or as otherwise appropriateOne data line 124 (see fig. 2 a) is transmitted. In this case, the signal U is addedSumOutput signal U corresponding to circuit 80c shown in FIG. 7Out
In FIG. 6b, the phase voltage UU、UV、UWRespectively assigned with the value WU、WV、WWThese values are also referred to as WUd、WVd、WWdLikewise, rising edge F L may also be givenUAssign the corresponding value WUu、WVu、WWu. The zero crossing of the phase voltage may also be assigned a corresponding value WU0、WV0、WW0These values can be used to identify the rotational speed n of the rotor 32 or of a crankshaft 17' coupled thereto, the angular position α of the rotor 32 depending on the plateau region of the phase signal or other region in between1Is also possible. These values are used for: according to the time difference Deltat1、Δt2、Δt3To determine the rotational speed of the motor 30. Use of the corresponding trigger circuits 80a, 80b (see fig. 4 and 5) generates a triggered phase signal U from the phase signalUt、UVt、UWtWherein the corresponding edge marks the corresponding value WU、WV、WW、WU0、WV0、WW0The point in time of occurrence of (c).
In this case, with a uniform arrangement of six permanent magnets in the electric machine 30, a total of 18 falling edges F L occur at equal distances from one another for each revolution, respectivelydAnd therefore 18 belonging values appear. Therefore, at the time difference Δ t1、Δt2Or Δ t3During this, the angle 360 °/18 = 20 ° is covered, which, as already mentioned at the outset, can also be used to detect the direction of rotation α of the rotor 32+、α-The exemplary determined 20 ° is the detectable angle increment. Furthermore, from this, the angular velocity ω can also be determinedi. The angular velocity is based on ωi= 20°/ΔtiTo obtain and associated rotational speed niAccording to niiPer 360 DEG 60s/min in minutesThe number of revolutions is obtained in units.
In principle, it is readily understood that the alternative is to fall edge F LDThe corresponding rising edge F L of phase U, V, W can also be usedUFor determining the direction α of rotation of the rotor 32+、α-And for determining the instantaneous speed n of the electric machine 30GenCorrespondingly, since the number of values per revolution is doubled, not only the direction α of rotation of the rotor 32 is obtained+、α-And the rotational speed nGenMoreover, the edges of these phases can be analyzed in a number of other ways and methods, for example by the rising edge of the respectively identical or corresponding phase F LUAnd a falling edge F LDAt intervals from each other or by rising edges F L of the same or all phases togetherUOr falling edge F LDTime intervals of the time interval.
Except for rising edge F LUAnd a falling edge F LDIn addition, the phase signal U may be usedU、UV、UWZero crossing W ofU0、WV0、WW0For determining the rotational speed n of the shaft 17Gen
In fig. 7a and b, a method for converting a plurality of input signals U is shownIn1、UIn2、UIn3Combined to output signal UOutThe circuit 80 c. Input signal UIn1To UIn3For example, may correspond to a corresponding phase signal UU、UVAnd UWAnd (4) associating. In principle, the application is not limited to three input signals. However, it is preferred that the output signal U of the flip- flop circuits 80a, 80b shown in fig. 4 or 5o1Or Uo2Or the output signal of another trigger circuit which preprocesses the phase signal of the motor in a suitable form, as the input signal UIn1To UIn3. In fig. 7b, the waveform obtained by means of the flip- flop circuits 80a, 80b with the corresponding phase signals as input signals for the flip- flop circuits 80a, 80b is taken as input signal UIn1、UIn2And UIn3To illustrate. In the present case, the circuit 2 has reference potentials U + and U-. However, the circuit arrangement can also be designed in principle such that the circuit is designed as a circuitThe device has only one fixed reference potential.
Input signal UIn1To UIn3Respectively assigned with its own pulse forming unit P1To P3The pulse-forming units are set up to convert the rising or falling edge of the input signal into a corresponding pulse Pf1、Pf2、Pf3、Pr1、Pr2、Pr3(see FIG. 7 b). Corresponding pulse forming unit P1、P2、P3Through a downstream output for each signal phase UIn1To UIn3The associated circuits being combined to a common signal USumAnd at the output terminal UoutIs provided. For this association, an AND link may be used, for example, as shown. However, other suitable correlation approaches may also be used for this purpose, for example correlation by means of transistors (of different types, for example MOSFETs or bipolar transistors) or operational amplifiers.
Pulse forming unit P1To P3In each case, a plurality of components, in particular capacitors, at least two resistors, transistors (different types are possible, for example MOSFETs or other transistor types can also be used in addition to the bipolar transistors depicted), and in each case an exclusive-or (Xor) gate. And an input signal UIn1To UIn3The rising and falling edges in (b) are associated with a pulse Pf1、Pf2、Pf3、Pr1、Pr2、Pr3Or characteristic features of these pulses, such as pulse length or pulse width TPf1、TPf2、TPf3、TPr1、TPr2、TPr3By applying a pulse-forming unit P to the corresponding pulse-forming unit1To P3The selection of the respective components in (a) is adjusted accordingly.
In this case, the capacitor C1 and the resistor R3 in the cell P1, for example, constitute a first time hysteresis node T11The capacitor C2 and the resistor R6 constitute a second dead time T12 in the pulse forming unit P2, and the capacitor C3 and the resistor R9 constituteAnother time-lag element T formed in the pulse forming unit P313. Pulse Pf1、Pf2、Pf3、Pr1、Pr2、Pr3Pulse width T ofPf1、TPf2、TPf3、TPr1、TPr2、TPr3Mainly by aligning time-lag links T11、T12、T13Is correspondingly defined, in particular, by the selection of the resistors R3, R6 and R9 and/or the capacitors C1, C2 and C3. By this, the pulse P can be corrected as can be seen in fig. 7bf1、Pf2、Pf3、Pr1、Pr2、Pr3And (6) coding is carried out.
In this case, the input signal UIn1To UIn3All edges of (b) obtain corresponding pulses Pf1、Pf2、Pf3、Pr1、Pr2、Pr3Said pulses having associated different pulse widths TPf1、TPf2、TPf3、TPr1、TPr2、TPr3. Thus, for example, inputting signal UIn3Is obtained with a pulse width TPr1Pulse P ofr1Input signal UIn1Is obtained to have a pulse width TPr2Pulse P ofr2And input a signal UIn2Has a pulse width TPf1Pulse P off1Wherein the pulse widths of the respective pulses have different widths (see fig. 7 b).
Thus, the pulse Pf1、Pf2、Pf3、Pr1、Pr2And Pr3Marks the input signal U at the falling edgeIn1To UIn3The precise location over time of the corresponding edge in (a). Time interval T from the subsequent rising edge of the encoded signalPf1、TPf2、TPf3、TPr1、TPr2And TPr3Contains information on: which direction the zero crossing of the respective input signal has, that is to say whether there is a falling or rising edge of the respective signal,and to which phase the zero crossing should be assigned. As already mentioned, all corresponding edges in the input signal, which correspondingly can also be associated with the zero crossing, are unambiguously encoded with the corresponding pulses.
The following boundary conditions apply in principle: the usable maximum pulse length of the respective pulse is obtained from the shortest possible time between two successive zero crossings and thereby from the maximum rotational speed of the electric motor 30. By means of respective summation signals U by means of corresponding control devicesIn1To UIn3Generated sum signal USumIn particular, the rotational speed can be determined.
In this case, the edges and the pulses P associated with the edgesf1、Pf2、Pf3、Pr1、Pr2And Pr3And their time intervals between each other may be used. In order to compensate for possible differences between rising and falling edges, the rotational speed can preferably be determined as a function of the time interval between two edges of the same type (rising or falling edge) or the assigned pulses of these two edges. In the present case, the spacing between the respective pulses (here, for example, for the pulse P of the falling signal edge) required for this purposef1、Pf2、Pf3To show) Δ t1、Δt2、Δt3According to time Deltat1= t2 + t3、Δt2= t4 + t5 and Δ t3= t6 and correspondingly a not depicted time period t 7. As already mentioned at the outset, these edges are provided by a corresponding arrangement of a plurality of permanent magnets within the electric machine. Thus, in the case of 6 permanent magnets (also referred to as pole pairs), a total of 18 falling edges Fl results for each revolution, each at the same distance from one another, as long as these pole pairs are arranged equidistantly in correspondence with one anotherdAnd thus 18 associated values. Therefore, at the mentioned time difference Δ t1、Δt2Or Δ t3During this period, the stepping angle 360 degrees is divided by 18 = 20 degrees, and the motor information of the motor can be used to determine not only the rotational speed but also the rotational direction α of the rotor 32+、α-But may also be used to determine the absolute position of the rotor 32 of the motor 30. It is easy to understand that: correspondingly using pulses Pr1、Pr2、Pr3To assign rising edges and the time intervals at which these rising edges can be processed.
By determining the function according toi= 20°/ΔtiAnd the angular velocity ω obtainediCan be according to ni= ωiThe rotation speed n is calculated in revolutions per minute by 360 DEG 60s/mini. The method step for determining the rotational speed is also referred to as step a 3. Further, the pulse information Pf1、Pf2、Pf3、Pr1、Pr2To Pr3May also be used to determine the direction of rotation α of the rotor 32+、α-. This step is referred to as a1 and is shown schematically in fig. 8 a. Therefore, based on the pulse Pf1、Pf2、Pf3、Pr1、Pr2To Pr3Can be deduced from the time sequence of the pulses, which can be based on the respective pulse width T in particular, of the direction of rotation of the rotor 32 of the electric machine 30Pf1、TPf2、TPf3、TPr1、TPr2、TPr3To distinguish them from each other. Therefore, if it has a pulse width TPr1Pulse P ofr1Followed by a pulse Pf1And is followed by Pr2Then the crankshaft is in the clockwise direction α+Rotating; and vice versa if the pulse width T is within the rangePr1Pulse P ofr1Followed by a pulse Pf3And is followed by a pulse Pr3Then the crankshaft is in the opposite direction α-And thus rotates in a counterclockwise direction. Thus, based on the pair pulse Pf1、Pf2、Pf3、Pr1、Pr2And Pr3The direction of rotation of the rotor 32 of the motor can be deduced in reverse.
Furthermore, the corresponding pulse width T can also be determinedPf1、TPf2、TPf3、TPr1、TPr2、TPr3To determine the corresponding pulse Pf1、Pf2、Pf3、Pr1、Pr2And Pr3Furthermore, the rotational angle position θ of the rotor 32 can be determined using the properties of the electric machine 30, in particular the previously mentioned positioning of the permanent magnets within the electric machine1. As already mentioned at the outset, the corresponding pulse Pf1、Pf2、Pf3、Pr1、Pr2And Pr3And at the input signal UIn1To UIn3Is associated with a falling edge. These rising and falling edges are in turn associated with motor parameters such as the layout of the permanent magnets, so-called pole pairs within the motor. Thus, the pulses and their relative spacing from each other describe the corresponding angular increment within which the rotor 32 of the motor is located.
For the rotational angular position theta of the rotor1The determination of or the step for determining the respective rotational angle position is illustrated in fig. 8 and this step is subsequently denoted by a 2. According to the sum signal USumTo the rotational angle position theta1Another design of the determination of (a) is illustrated in detail in fig. 8 c. In this case, an arbitrary position point P that should be determined is assumed. In the present case, the point is at pulse Pf1And pulse Pr2But may in principle be chosen arbitrarily. Thus, the position is within an angular increment that is passed by the pulse Pf2And pulse Pr2To be associated with the pole pairs of the motor 30. Thus, by using the pulse Pf1Time interval Δ t ofPf1And with respect to pulse Pr2Time interval Δ t ofPr2And using the speed of rotation, especially in pulses Pf1And Pr2The average rotational speed in the time period in between can also explain more precisely the orientation of the rotor at the position P beyond the angular increment.
In fig. 8d, a flow chart of a method according to the first embodiment is generally illustrated. In step S1, at least two input signals, preferably in the form of phase signals, are determined. In step S2, signal U is inputIn1To UIn3Rising edge Fl ofuAnd falling edge FldIn the form of edge utilization phaseCorresponding pulse Pf1、Pf2、Pf3、Pr1、Pr2And Pr3Is encoded. The signal sequences derived therefrom are combined in step S3 to form a sum signal USum. Depending on the sum signal generated in step S3, it may be possible to depend on the pulse P as described earlierf1、Pf2、Pf3、Pr1、Pr2And Pr3The rotational speed of the shaft, in particular of the rotor 32 of the electric machine 30, is determined in a step A3, the rotational direction of the shaft, in particular of the rotor 32 of the electric machine 30, is determined in a step a1, and the rotational angle position of the shaft, in particular of the rotor 32 of the electric machine 30, is determined in a step a2, and the rotational speed, rotational angle position or rotational direction of the crankshaft 17 of the internal combustion engine 110 can also be determined from this by the coupling of the rotor to the crankshaft of the electric machine 30. In principle, it is easy to understand that: steps a1 to A3, in which the rotational speed, the rotational angle position or the rotational direction of the rotor is determined, can alternatively be applied, but can also be applied cumulatively.
In addition to the two embodiments shown, other circuits are also conceivable which divert at least one of the input signals to an output with a well-defined extension, in particular a signal pulse with a well-defined length, and superimpose it with the other (unaltered) input signals, so that later on when the sum signal is evaluated it is possible to deduce inversely which signal edge is caused by which input signal.

Claims (17)

1. A method for determining a rotational variable, in particular a rotational direction (α), of a shaft (17), in particular a crankshaft (17') of an internal combustion engine (112)+、α-) The internal combustion engine is directly or drivingly coupled to an electric machine (30) comprising a rotor (32) and a stator (33) having at least two phase windings (U, V, W) from which at least one phase signal (U) is derivedU、UV、UW、IU、IV、IW) Therein is describedThe phase signal (U)U、UV、UW、IU、IV、IW) Respectively have a rising edge (Fl)Uu、FlVu、FlWu) Falling edge (Fl)Ud、FlVd、FlWd) And/or zero crossing (Fl)U0、FlV0、FlW0) Wherein a plurality of phase signals (U) comprising the motor (30) are generatedU、UV、UW、IU、IV、IW) Sum signal (U)Sum) So that at said sum signal (U)Sum) Respectively giving said rising edge (Fl)Uu、FlVu、FlWu) Falling edge (Fl)Ud、FlVd、FlWd) And/or zero crossing (Fl)U0、FlV0、FlW0) Assigning a characteristic pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Wherein said pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Is used to determine the rotational speed (n) and the rotational angle position (theta ) of the rotor (32)1) Or direction of rotation (α)+、α-)。
2. Method according to claim 1, wherein at said sum signal (U)Sum) Respectively by corresponding phase signals (U)U、UV、UW、IU、IV、IW) Falling edge (Fl)Ud、FlVd、FlWd) Generating a first pulse (P)f1、Pf2、Pf3) But also by corresponding phase signals (U)U、UV、UW、IU、IV、IW) Rising edge (Fl)Uu、FlVu、FlWu) Generating other pulses (P)r1、Pr2、Pr3)。
3.Method according to claim 1 or 2, wherein assigned to have a rising edge (Fl)Uu、FlVu、FlWu) Or falling edge (Fl)Ud、FlVd、FlWd) Has a constant first pulse width (T)Pf1、TPf2、TPf3) While the pulses assigned to the respectively other edge type have a constant, but mutually different, other pulse width (T)Pr1、TPr2、TPr3)。
4. Method according to one of the preceding claims, wherein the sum signal (U) is determined by determining the sum signal (U)Sum) In which there is a first pulse width (T)Pf1、TPf2、TPf3) One determines that there is a falling edge (Fl)Ud、FlVd、FlWd) And in determining the sum signal (U)Sum) Among other pulse widths (T)Pr1、TPr2、TPr3) One of them is asserted to have a rising edge (Fl)Uu、FlVu、FlWu)。
5. Method according to one of the preceding claims, wherein the sum signal (U) is determined by determining the sum signal (U) from the signalsSum) Two pulses (P) inf1、Pf2、Pf3、Pr1、Pr2、Pr3) At least one time difference (Δ t) therebetween1、Δt2、Δt3) To determine said rotational speed (n).
6. Method according to one of the preceding claims, wherein the pulse (P) is determined by determining the pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) To infer a first rotational direction (α), at least one first time series (A1)+) Or by determining the pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Is determined by at least one other time series (A2)And, alternatively, with said first direction of rotation (α)+) Different directions of rotation (α)-)。
7. Method according to one of the preceding claims, wherein the pulse width (T) is determined by determining the pulse width (T)Pf1、TPf2、TPf3、TPr1、TPr2、TPr3) To determine the corresponding pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) And according to said pulses (P) using the characteristics of said motor (30)f1、Pf2、Pf3、Pr1、Pr2、Pr3) To determine the rotational angle position (theta) of the rotor (32)1)。
8. The method according to claim 7, wherein further two adjacent pulses (P) are usedf1、Pf2、Pf3、Pr1、Pr2、Pr3) And at a position (P) and said pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) At least one time interval (Δ t) between one of themPf1、ΔtPr2) Determining a rotational angle position (theta) of the rotor (32)1)。
9. Method according to one of the preceding claims, wherein the determined rotational speed (n) of the shaft (17) is used for controlling the internal combustion engine (112), in particular for controlling the ignition and/or injection of fuel into at least one cylinder of the internal combustion engine (112).
10. For transmitting a plurality of phase signals (U)U、UV、UW、IU、IV、IW) Generating a sum signal (U)Sum) Can be used for determining a shaft (17), in particular a crankshaft (17' of an internal combustion engine (112)In particular the rotational speed (n) and the rotational angle position (theta )1) Or direction of rotation (α)+、α-) The internal combustion engine is directly or drivingly coupled to an electric machine (30) comprising a rotor (32) and a stator (33) having at least two phase windings (U, V, W) from which at least one phase signal (U) can be derived in each caseU、UV、UW、IU、IV、IW) Said phase signal having a rising edge (Fl)Uu、FlVu、FlWu) Falling edge (Fl)Ud、FlVd、FlWd) And/or zero crossing (Fl)U0、FlV0、FlW0) Said device having at least two inputs (U)1、U2、U3) Phase signals (U) are respectively transmitted through the at least two input terminalsU、UV、UW、IU、IV、IW) Conducting to a coding unit (80 c), wherein the coding unit (80 c) transmits the individual phase signals (U)U、UV、UW、IU、IV、IW) Combined into a sum signal (U)Sum) And the phase signal (U) is converted into a phase signal (U)U、UV、UW、IU、IV、IW) Is encoded such that at least one of the signals (U) is added to the sum signal (U)Sum) Respectively to said at least one phase signal (U)U、UV、UW、IU、IV、IW) Rising edge (Fl)Uu、FlVu、FlWu) And/or falling edge (Fl)Ud、FlVd、FlWd) Assigning a characteristic pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Wherein the coding unit (80 c) sums the signals (U)Sum) Output to output terminal (U)Out) For determining said rotation quantity.
11. The method of claim 10Device, wherein said coding unit (80 c) has at least one time lag bin (T)11、T12、T13) The time-lag loop can be assigned to at least one phase signal (U) of the electric machine (30)U、UV、UW、IU、IV、IW) And the time-lag element gives the at least one phase signal (U)U、UV、UW、IU、IV、IW) The characteristic features are loaded.
12. The apparatus according to claim 10 or 11, wherein said at least one time lag link (T)11、T12、T13) Respectively having a resistor (R3, R6, R9) and a capacitor (C1, C2, C3), wherein the characteristic feature, in particular the pulse (P)f1、Pf2、Pf3、Pr1、Pr2、Pr3) Pulse width (T) ofPf1、TPf2、TPf3、TPr1、TPr2、TPr3) The parameters can be selected by the selection of the respective resistors (R3, R6, R9) and/or capacitors (C1, C2, C3).
13. The device according to claim 11 or 12, wherein a trigger circuit (80 a, 80 b) is preceded by the coding unit (80 c), the trigger circuit generating a triggered phase signal (U)UT) The triggered phase signal is delivered to an input (U) of the coding unit (80 c)1、U2、U3) At least one input terminal.
14. The apparatus of claims 10-13, wherein the trigger circuit (80 b) has a skew-link (T) with a resistance (R)1c) And a capacitor (C)1c)。
15. A computing unit, preferably an engine control device (122) for an internal combustion engine (12), which is set up by a corresponding integrated circuit and/or by a computer program stored on a memory as: performing the method according to one of claims 1 to 9.
16. A computer program which, when executed on a computing unit, causes the computing unit to perform a method according to one of claims 1 to 9.
17. A machine readable storage medium having stored thereon a computer program according to claim 16.
CN201880080235.2A 2017-12-15 2018-11-29 Method and device for determining the rotational direction of a crankshaft of an internal combustion engine Active CN111448380B (en)

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