CN110007108B - Device for evaluating a phase signal of an electric machine - Google Patents

Abstract

The invention relates to a method for evaluating a phase signal (U) of an electric machine (30) _U 、U _V 、U _W 、I _U 、I _V 、I _W ) Having an input (U) and a device having an input (U) _I2 ) And an output terminal (U) _O2 ) An operational amplifier (O) is arranged between the input and the output, wherein the operational amplifier (O) and the output (U) are arranged _O2 ) A blocking device (B) is arranged between the two, such that the triggered phase signal (U) _Ut ) To the output terminal (U) _O2 ) Is transmitted for a duration (Z) ₀ ) Is suppressed, said duration depending on the hysteresis mechanism (T).

Description

Device for evaluating a phase signal of an electric machine

Technical Field

The invention relates to a device for evaluating a phase signal of an electric machine for determining a rotational speed or a rotational angle position of a shaft.

Background

The rotational speed of the crankshaft of an internal combustion engine is a basic input for various functions of an electronic engine controller. For its acquisition, the marks can be provided at the same angular pitch on a body that rotates with the crankshaft of the internal combustion engine. The sweep of the marker, which is the result of the rotation of the crankshaft, can be detected by a sensor and can be transmitted as an electrical signal to the evaluation electronics.

For a corresponding rotational angle position of the crankshaft, the electronics determines a signal stored for this purpose or a measured time difference, respectively, and can determine the angular speed and thus the rotational speed on the basis of the known angular distance between two markers for which the signal is used, the time difference being the time difference between the two markers. In the case of motor vehicles, in particular motorcycles, mopeds (mopeds) or mopeds (Kraftr 228der), the marking can be provided, for example, by the teeth of a metallic gear wheel, a so-called sensor wheel, which is preferably made of a ferromagnetic material, which by its movement causes a change in the magnetic field in the sensor. The gap of some teeth can be used as a reference mark for identifying the absolute position. In passenger cars at most 60-2 teeth (60 teeth evenly distributed, wherein 2 teeth remain empty as reference marks) are used, while in motorcycles or motorbikes for example also 36-2, 24-2 teeth are used. In the principle of this indirect speed determination or indirect determination of the rotational angle position of the crankshaft, the resolution of the speed signal or the absolute detection of the rotational angle position is determined by the number of teeth and by a reliable detection of the reference marking.

With every modern vehicle having an internal combustion engine, an electric machine is mounted in the form of a generator, which is driven by rotation of a crankshaft. This provides an electrical signal and is used to supply the vehicle with electrical energy and to charge the vehicle battery. Without such a generator, a predefined operation of the vehicle is not possible or is possible only for a very short time.

For example, in EP 0664887 B1, the use of the electrical output of an electric machine (generator) driven by a crankshaft is used for speed determination. For this purpose, the phase of the generator, at which the pulsating direct voltage is applied, can be used as a reference. When using a plurality of phases for determining the rotational speed, the respective signals of the phases are usually detected and individually transmitted to an evaluation unit, which determines the rotational speed of the generator from the signals. In order to preprocess the respective phase signals, evaluation circuits are used in the prior art, by means of which the phase signals of the respective phases are preprocessed for further processing. However, these known devices are less resistant to noise or other signal fluctuations in the signal.

It is therefore desirable to improve the evaluation circuit such that it is less sensitive to the influence of interference noise in the phase signal to be evaluated. In this way, the acquisition of the rotational speed or the rotational angle position of the rotor and therefore of the crankshaft coupled thereto can be further improved in particular from the phase signal of the electric machine.

Disclosure of Invention

According to the invention, a device having the features of claim 1 is proposed. Advantageous embodiments are the subject matter of the dependent claims and the following description.

Advantages of the invention

In the context of the present invention, the device for evaluating the phase signals of the electric machine is used to signal-technically preprocess or evaluate at least one of the phase signals of the electric machine. Such a device has an input and an output, between which an operational amplifier is arranged, wherein the operational amplifier generates a triggered phase signal from a phase signal applied at the input, wherein a hysteresis mechanism and a blocking device are arranged between the operational amplifier and the output in such a way that a transmission of the triggered phase signal to the output is suppressed for a time duration which depends on the hysteresis mechanism. The blocking device is formed by two switches and an inverter stage and prevents new switching within the delay time of the hysteresis mechanism after switching the output signal. The triggered phase signal differs from the conventional phase signal in particular in that it contains only a subset of the data points, which are currently generated by a corresponding temporal manipulation of the operational amplifier.

Currently, the time regulation (zeitlich Regelung) of the wiring (Beschaltung) of an operational amplifier is produced by means of a hysteresis mechanism which is arranged downstream of the operational amplifier and is connected to its output. The hysteresis mechanism thus makes it possible to achieve a temporal filtering of the phase signal which arrives at the operational amplifier, as a result of which, in particular, a temporal filtering and corresponding suppression of the interference signal, in particular around the zero crossing of the phase signal, can take place.

In a preferred embodiment, the hysteresis mechanism has a resistor and a capacitor. The capacitance of the hysteresis mechanism is supplied via the output of the operational amplifier and via the upstream resistor and is thereby charged and thus forms a time-controlled switching element. After switching the output of the evaluation circuit, in particular in the case of high-frequency switching or noise at the input, a new switching of the output of the evaluation circuit can therefore be suppressed by a combination of a hysteresis mechanism, which is arranged after the hysteresis mechanism, and a blocking device, which is preferably designed in the form of two R/S flip-flops and an inverter stage or in the form of another electronic circuit, which has a corresponding functionality, until a time predefined by the hysteresis mechanism has elapsed. The predefined time is therefore a characteristic time constant for the hysteresis mechanism, which functions as a temporal control mechanism, wherein the time constant is determined by a respective resistor or capacitor or is selectable accordingly.

In general, the aforementioned operational amplifier can be understood as an electronic component which performs the following tasks: at the output it is shown whether the input signal has a positive or negative voltage. This therefore includes all conceivable electronic circuits which implement a similar function. Possible embodiments of the operational amplifier can comprise, for example, a classical operational amplifier, a comparator or a differential amplifier or similar circuits.

In a preferred embodiment, the capacitance and the resistance are designed such that the transmission of the triggered phase signal is suppressed in the time range of the phase signal around a zero crossing. This is particularly advantageous because, in particular, disturbances in the signal occur around zero crossings of the phase voltages due to unbalanced states, which disturbances can be separated or suppressed particularly effectively by such a circuit. For this purpose, the respective time constant can be determined by a corresponding selection of the resistance or the capacitance, in particular by a selection of the conductivity of the resistance and/or the capacitance of the capacitor.

In a further preferred embodiment, at least one of the switches of the blocking device is designed as an R/S trigger. By using R/S flip-flops, the corresponding switching threshold values can be better adapted, in particular around the zero crossings of the phase signal.

In a further preferred embodiment of the device for evaluating phase signals, this device is followed by an encoding device for generating a sum signal from a plurality of phase signals of the electric machine, wherein the encoding device has at least two inputs, at least one of which is connected to the output of the device for evaluating phase signals for exchanging triggered phase signals, wherein the encoding device encodes at least one of the triggered phase signals and combines the respective triggered phase signals into a sum signal, wherein the encoding device outputs the sum signal to the output, in particular for detecting the rotational speed of the electric machine. The phase signal in the form of the triggered phase signal can be further processed particularly simply by means of a coding device into a sum signal, which is preprocessed by a corresponding evaluation circuit, wherein from the sum signal and the individual triggered phase signals contained therein, an exact rotational speed of the shaft of the electric motor or a rotational angle position of the shaft can be calculated. In this case, advantageously, only one data line is required, in particular for the transmission of the sum signal, which makes such a system particularly simple to implement. In order to evaluate the respective triggered phase signals and thus determine the rotational speed or the rotational angle position, the respective triggered phase signals can be taken into account in the sum signal, since these triggered phase signals are encoded by the encoding device and can thus be distinguished.

Within the framework of a further preferred embodiment, the coding device has at least one further hysteresis mechanism. This hysteresis means serves, in particular in combination with a plurality of Xor gates or other electronic circuits having a corresponding functionality, to assign a respective characteristic property to at least one phase signal. Depending on the respective hysteresis mechanism used, the respective phase signal is assigned a characteristic property by using different hysteresis mechanisms for the different phase signals. The triggered phase signal thus encoded can therefore be distinguished particularly simply in the sum signal. Furthermore, this is facilitated by the phase positions of the phases with respect to one another, which are fixed and known with reference to the structural preconditions of the electric machine, and other influencing variables. In principle, it is advantageous to perform a corresponding preprocessing of the phase signal by the evaluation circuit in the framework of the triggered phase signal, since: in this way, the respective phase signal edges can be assigned in a particularly characteristic manner, and the corresponding detection of the edges can be taken into account in a particularly simple manner for determining the rotational speed or the rotational angle position of the electric machine.

Further advantages and solutions of the invention result from the description and the enclosed drawing.

Drawings

Fig. 1a to c show schematic diagrams (a, b) of an electric machine coupled to an internal combustion engine, and an associated signal profile (c);

fig. 2 schematically shows an electric machine with a corresponding, associated phase signal;

fig. 3a and 3b schematically show an evaluation circuit (a) for the phase voltages and phase signals (b) related to the phase voltages;

fig. 4a to 4c schematically show an evaluation circuit (a) for the phase voltages, phase signals (b) associated with the phase voltages, and typical signal profiles at the individual components of the evaluation circuit, according to a further embodiment;

fig. 5a and 5b show a phase signal (a) of the phase of a three-phase motor, which results from the voltage profile, and an enlarged representation (b) of the phase signal;

fig. 6a and 6b schematically show a circuit (a) for combining a plurality of phase signals and a temporally changing sum signal (b) of the individual phase signals, according to a first embodiment; and

fig. 7a and 7b schematically show a further circuit (a) for combining a plurality of phase signals and a temporally changing sum signal (b) of the individual phase signals, in accordance with a further specific embodiment.

Detailed Description

Fig. 1a shows an internal combustion engine 112 to which an electric machine 30 is connected directly or in a variable-speed manner, 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 30 _Gen And the rotational speed n of the crankshaft 17 _BKM And angular position theta of the rotor of motor 30 ₁ And the rotational angular position theta of the crankshaft 17' have a fixed ratio to each other. Furthermore, a charging controller LR is assigned to electric machine 30, which supplies battery B in vehicle electrical system 110 with energy depending on its remaining capacity.

Furthermore, a computing unit, in particular an engine controller 122, is provided, which exchanges data with the electric machine 30 or with the internal combustion engine 112 via a communication link 124 and is provided for actuating the internal combustion engine 112 and the electric machine 30, respectively. The direction of rotation α +, α —, of rotor 30 and its shaft 17 is also illustrated, α + describing a forward rotation in the preferential direction (Vorzugsrichtung) of internal combustion engine 112 and α —, a reverse rotation in the opposite direction. The angular position theta of the crankshaft 17' or theta of the rotor 32 is also specified ₁ 。

In fig. 1b, the motor 30 is again schematically shown in an enlarged form. The electric machine 30 has a rotor 32 with a shaft 17, which has field windings and a stator 33 with stator windings U, V, W. It therefore relates to a separately excited machine, as is usual in particular in motor vehicles. Then, especially for motorbikes, especially for small or light motorbikes, it is common to use motors with permanent magnets (i.e. permanently excited electrical machines). Within the framework of the invention, both types of electric machines can in principle be used, wherein in particular the method according to the invention is not dependent on the use of the respective type of electric machine (for example, a permanently excited electric machine or a separately excited electric machine).

The electric machine 30 is designed as an alternator, for example, in which three phase voltage signals are induced, which are phase-shifted by 120 ° relative to one another. Such a three-phase generator (drehstromlichmanschine) is usually used as a generator in modern motor vehicles and is suitable for carrying out the method according to the invention. Within the framework of the invention, it is in principle possible to use all motors independently of their number of phases, wherein in particular the method according to the invention is not dependent on the use of the respective type of motor.

The three phases of the alternator 30 are denoted U, V, W. The voltage dropped at the phase is rectified by a rectifying element in the form of a positive diode 34 and a negative diode 35. Thus, a generator voltage U is applied between the poles B + and B- _G And the negative pole is grounded at the generator voltage. Such an alternator 30 supplies, for example, a battery B or other electrical consumers in the vehicle electrical system 110.

Fig. 1c shows three graphs which show the associated voltage profile with respect to the rotational angle of the rotor 32 of the electric machine 30. In the upper diagram, the course of the voltage at the phases U, V, W is plotted. In general, it should be understood that the numbers and value ranges illustrated in this diagram and in the subsequent diagrams are exemplary only, and thus, in principle, do not limit the invention.

The generator voltage U is shown in the middle diagram _G The generator voltage is formed by the envelope curves of the positive and negative half-waves of the voltage course U, V, W.

In the lower diagram, the rectified generator voltage U is finally shown _G- (see FIG. 1 b) together with this generator voltage U _G- Said generator voltage and the effective value are both applied between B + and B-.

In fig. 2, a stator 33 is schematically shown, having phases U, V, W and a positive diode 34 and a negative diode 35 from fig. 1 b. It should be understood in principle that the rectifier elements shown here in the form of the positive diode 34 and the negative diode 35 can also be designed as transistors, in particular as MOSFETs (metal-oxide-semiconductor field effect transistors) (not shown), in the case of active rectifiers. Furthermore, the nomenclature used hereinafter for the voltages and currents that occur is shown.

U _U 、U _V 、U _W Alternatively, the phase voltages of the associated phases U, V, W are represented, as they drop between the outer conductor and the star point of the stator 33. U shape _UV 、U _VW 、U _WU Representing the voltage between the two phases or between their associated outer conductors.

I _U 、I _V 、I _W The phase currents of the respective outer conductors of the phases U, V, W to the star point are indicated. I denotes the total current of all phases after rectification.

FIG. 3a schematically shows a schematic representation for the phase voltage U _U And an evaluation circuit 80a in the form of a schmitt trigger, and the phase voltage U of the phase U of the electric motor 30 _U (upper diagram) and triggered phase voltage U _Ut The triggered phase voltage is detected by means of an evaluation current 80a, which is selected as an example. By means of such an evaluation circuit 80a, the input signal U is referenced _I1 Generates an output signal U _O1 If the output signal is referenced to the triggered phase voltage U _Ut As shown in the lower diagram of fig. 3 b), the input signal currently corresponds to the phase voltage U _U . Correspondingly, the horizontal dashed line illustrated in the upper graph (see fig. 3 a) illustrates the switching threshold of the evaluation circuit 80 a.

According to instantaneous output voltage U _O1 Resistance R in the feedback branch of the operational amplifier O ₁ And R ₂ Resulting in these different switching thresholds at the output. The behavior shown in the signal change can thus be achieved by predetermining the respective switching threshold and it is ensured that signal noise around the switching point does not lead to a changing output level of the operational amplifier O. By means of the evaluation circuit, a triggered phase signal U can be generated _Ut The triggered phase signal can be evaluated in a simple manner, wherein steep edges and the triggered phase signal U _Ut Can be taken into account for the determination of the rotational speed of the motor 30.

Fig. 4 shows a further embodiment of an evaluation circuit 80b, by means of which an input signal U is referenced _I2 To generate an output signal U _O2 Said input signal corresponding exemplarily to the phase voltage U _U The output signal currently corresponding to a triggerPhase voltage U of _Ut . The phase voltage U is shown in the lower diagram of fig. 4 b) _Ut . It should be understood that other phase voltages U _U 、U _V 、U _W Is also applied to the input terminal U _I2 And can result in a voltage at the output U _O2 Or U _O2U 、U _O2V 、U _O2W Phase voltage U triggered by output _Ut 、U _Vt 、U _Wt (see in particular figures 6 and 7 for this purpose).

The evaluation circuit 80b has a blocking device b for the purpose of correcting the corresponding phase signal U _U 、U _V 、U _W The temporal filtering of (2) performs noise suppression. The blocking device b is arranged downstream of the at least one operational amplifier O, the phase signal U _U 、U _V 、U _W Applied to the input terminal O of the operational amplifier _in To (3). The blocking device B has a hysteresis mechanism T and two switches F ₁ 、F ₂ And an inverter stage I, the adjustable delay time (Totzeit) of the hysteresis mechanism defining a time constant for time filtering. The hysteresis mechanism T has a resistance R _b And a capacitor C _b The capacitor is charged with a current that flows through the output of the operational amplifier O. At the output U of the switching evaluation circuit _O2 Then, by passing through the hysteresis mechanism T and the first switch F ₁ Combination of components in switch F ₁ Preferably in the form of an R/S-flip-flop, the pulses of which have a positive output voltage (High-Level, high) with respect to a rest voltage (Low-Level, low). The rising edge of the pulse signal is in this case the signal O at the output of the operational amplifier O _out The rising edges occur simultaneously. The subsequently falling edge of the pulse occurs after the delay time of the hysteresis mechanism T. In parallel, the output signal O of the operational amplifier O _out Is generated by an inverter stage I. This inverted signal is applied to the set input S of a second switch F2, which is preferably designed in the form of an R/S flip-flop, and a pulse signal is applied to the reset input R. Here, switch F ₂ Passing a first signal edge of the inverted signal to an output U _O2 And then prevents a renewed switching of the output as soon as the high level of the pulse signal is applied or the output signal itself already has a high level.

In this way, the output U is provided _o2 At the input O of the operational amplifier 0 _in Noise in the range of falling edges: as long as there is no high level at the reset-input R, the switch F2 cannot switch the output again. For the input terminal O of the operational amplifier _in In the case of a rising edge of the switch F ₂ Reset-at the input R there is a switch F ₁ Pulse of the pulse signal. This results in the switch F ₂ Will output end U _o2 Set to low. At the input end O _in Possible noise in the range of the rising edge of (b) is suppressed by: as long as a high level is present at the reset input R, the switch F ₂ The output terminal U cannot be replaced _o2 Set to high. Thus, during the pulse length, the output U is not realized _o2 And possible noise is suppressed. Characteristic time constants for such noise suppression are obtained by correspondingly selecting the resistor R _b And a capacitor C _b To be implemented.

By using the blocking device B, the corresponding noise effects, as they surround the time range or duration Z in fig. 4B, in the upper diagram ₀ Shown by the zero line in (each characterized by a circle). This results in a trigger phase signal U _Ut 、U _Vt 、U _Wt Improvement of signal quality. In fig. 4C) is shown at the output of the operational amplifier O, at the resistor R or the capacitor C, at the inverting stage I or at the flip-flop F ₁ Or F ₂ Typical signal variation processes of (a).

Compared to the schmitt-trigger-solution (see fig. 3), the advantage of this circuit is: with phase signal U _U 、U _V 、U _W Is detected, wherein, in respect of schmitt triggers, substantially more precise zero crossings of the input signal of the form (a) are detectedFor the phase signal, the switching threshold is continuously required by the unit 80a>0 (see fig. 3). Thereby, the phase signal U can be used _U Characteristic value W of _U0 Alternatively, a corresponding parallel arrangement of these trigger circuits can be used when there are multiple phase signals. These characteristic values W _U0 、W _V0 、W _W0 In particular, this can be taken into account for determining 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 threshold values, but by temporal filtering by means of a hysteresis mechanism. Switching the output U based on zero crossing at the input _o2 In the first (short) time thereafter, this hysteresis mechanism prevents the output U from going out _o2 (especially due to noise) is switched back directly again. The output U can be triggered only after the end of the delay time and after the subsequent zero crossing _o2 In which only then is the trigger switch F ₁ And/or F ₂ Wiring and outputting signal U _o2 With triggered phase signal U _Ut Is arranged after the operational amplifier O and the hysteresis mechanism T.

Now, three trigger phase voltage signals U are shown in fig. 5a _Ut 、U _Vt 、U _Wt The trigger phase voltage signal has a potential reference with respect to time with respect to B "in the three diagrams, as it appears after evaluation in a generator with an outer rotor having six permanent magnets, in particular by means of an evaluation circuit 80B. Such a representation of an electric machine 30 with a three-phase stator winding 33 is only to be seen as an example, wherein, in principle, without limiting the generality, electric machines with a correspondingly required number of phases, permanent magnets or field coils can also be used. Likewise, instead of star-shaped stator-coil wiring, delta-wiring or other wiring can also be selected.

In the case of an electric machine 30 with current output, the phase voltage U in a first approximation _U 、U _V 、U _W Is rectangular.This is explained in particular by the following way: by means of the generator voltage, the positive or negative diode conducts in the flow direction and therefore measures approximately 15-16 volts (battery charging voltage and voltage at the positive diode in the case of 12V lead-acid batteries) or negative 0.7-1 volts (voltage at the negative diode). The measured reference potentials are respectively ground. Other reference points, such as star junctions of the stator, can also be selected. This indicates a deviating signal-changing course, without however changing the information that can be evaluated, its extraction and analysis.

The diagrams shown in fig. 5a are enlarged in fig. 5b and shown together in one diagram. Here, a uniform phase shift can be clearly recognized. In the following, the phase voltage U is used partially synonymously _U 、U _V 、U _W By means of either the phase voltage U processed or triggered by the evaluation circuit 80a or 80b _Ut 、U _Vt 、U _Wt Because of the phase voltage U processed _Ut 、U _Vt 、U _Wt Generated from the phase voltage U _U 、U _V 、U _W 。

During one complete rotation of the rotor 32 of the electrical machine 30, the voltage signal is repeated six times by six magnets, in particular permanent magnets, so-called pole pairs. Thus, each phase, that is to say each phase voltage U per revolution of each rotor 32 _U 、U _V 、U _W Six falling edges FL occur _D And six rising edges FL _U (for the corresponding phase FL _UU 、FL _VU 、FL _WU And FL _UD 、FL _VD 、FL _WD ）。

These edges define the angular section, i.e. exactly the angular section covered by the magnets along the radial outer circumference of the stator. Accordingly, when the corresponding edge FL is identified _U Or FL _D At any time, an absolute reference point for each cycle (Umlauf) can be obtained, which uses the phase voltage U, for example, with reference to a reference magnet _U 、U _V 、U _W Different from the other magnets or phase voltages U _Ut 、U _Vt 、U _Wt Is triggered to change.

Now, with suitable means, the falling edge FL of the phase voltage can be identified _D And rising edge FL _U Or a zero crossing. For example, for each phase voltage, the phase voltage U can be generated by means of the circuit shown in fig. 3 or 4 _Ut 、U _Vt 、U _Wt In the form of a TTL signal and can be transmitted to a controller, in particular the engine controller 122, in which the edge FL is evaluated _U . The rotational speed n thus obtained can then be taken into account for controlling the internal combustion engine 110. The required triggering device (see fig. 3 or fig. 4) can be integrated in the control unit or in the control electronics (e.g. control unit, regulator for the battery voltage) and/or, in the case of an active rectifier, in the respective generator regulator, or can also be assigned to it externally. Especially for the case of the use of a controller, especially an engine controller 122 (see fig. 1 a), the individual TTL-signals can be combined to a sum signal U _Sum (see fig. 6 and 7), and/or can be suitably integrated by upstream disposed combined electronics or otherwise, and can be communicated only by data lines 124 (see fig. 1 a).

Value W _U 、W _V 、W _W Are respectively matched with phase voltage U _U 、U _V 、U _W Or triggered phase signal U _Ut 、U _Vt 、U _Wt Of the corresponding falling edge, said value also being denoted W _Ud 、W _Vd 、W _Wd . Likewise, the corresponding value W _Wu 、W _Vu 、W _Wu Can also be assigned to the rising edge FL _U . Corresponding value W _U0 、W _V0 、W _W0 The zero crossings of the phase voltages can also be assigned in each case. These values can also be used to detect the rotational speed n of the rotor 32 or of the crankshaft 17' coupled thereto. The rotation of the rotor 32 is recognized with reference to plateau regions (plateau regions) of the phase signal or other regions therebetweenAngular position alpha ₁ Are also possible. Said value being used to reference the time difference Δ t ₁ 、△t ₂ 、△t ₃ To obtain the rotational speed of the motor 30. Triggered phase signal U is generated from the phase signal using corresponding trigger circuits 80a, 80b (see fig. 4 and 5) _Ut 、U _Vt 、U _Wt Wherein the corresponding edge marks the corresponding value W _U 、W _V 、W _W 、W _U0 、W _V0 、W _W0 The time of occurrence of (c).

Here, when six permanent magnets are uniformly arranged in the motor 30, a total of 18 falling edges FL appear _d And, thus, 18 assigned values per revolution occur at equal distances from each other, respectively. Thus, at the time difference Δ t ₁ 、△t ₂ Or Δ t ₃ During which an angle of 360/18 = 20 is swept. As already mentioned at the outset, this can also be taken into account for identifying the direction of rotation α +, α — of the rotor 32, wherein the exemplary acquired 20 ° represents the angle increment that can be detected. In addition, the angular velocity ω can be obtained thereby _i . This is represented by ω _i =20°/△t _i Deriving, and, associated therewith, a rotational speed n _i From revolutions per minute n _i =ω _i 60s/min at/360 deg.C.

In principle, it can be understood that the falling edge FL is replaced _D Besides, the rising edge FL of the corresponding phase U, V, W _U Can also be used to determine the direction of rotation α +, α —, of the rotor 32 and also the instantaneous speed n of the electric motor 30 _Gen . By multiplying the value per revolution by a double factor, the direction of rotation α +, α -and the speed of rotation n of the rotor 32 are correspondingly determined _Gen Higher resolution of the image. Furthermore, the edges of the phases can be evaluated in various other ways, for example by the rising edges FL of the respective identical phases _U And falling edge FL _D Or the respective phases with each other, or by the rising edge FL of the same phase _U Or falling edge FL _D Or a time interval common to all phases.

Except for rising edge FL _U And falling edge FL _D In addition, the phase signal U can also be taken into account _U 、U _V 、U _W Zero crossing point W of _U0 、W _V0 、W _W0 For obtaining the rotational speed n of the shaft 17 _Gen 。

In fig. 6a and 6b and fig. 7a and 7b, respectively, a method for converting a plurality of input signals U is shown _In1 To U _In3 Synthesize into output signal U _Out The circuits of (fig. 6a and 7 a) and the input and output signals associated therewith (fig. 6b fig. 7 b). Input signal U _In1 To U _In3 Can be associated, for example, with a corresponding phase signal U _U 、U _V And U _W And (4) associating. Preferably, the input signal U _In1 To U _In3 However, the output signal U of the flip- flop circuits 80a, 80b shown in fig. 3 or fig. 4 is used as the output signal U _o1 Or U _o2 Said output signal being triggered by a phase signal U _Ut 、U _Vt 、U _Wt In the form of (1). The corresponding lines have a reference potential ground G which is fixed in each case _ND . The evaluation circuits 80c (fig. 6) and 80d (fig. 7) each have different, characteristic RC components T ₁₁ 、T ₁₂ Or T ₂₁ And T ₂₂ . By means of these RC-components T ₁₁ 、T ₁₂ Or T ₂₁ And T ₂₂ To encode C respective input signals U _In1 To U _In3 So that it outputs a signal U _Out Sum signal U _Sum Having a characteristic course of change therein and being correspondingly distinguishable, the RC-component having a corresponding resistance R ₁₁ 、R ₁₂ 、R ₂₁ 、R ₂₂ And a capacitor C ₁₁ 、C ₁₂ 、C ₂₁ 、C ₂₂ 。

Here, in fig. 6, the signal U is input _In1 To U _In3 At least partially by means of RC-members T ₁₁ And T ₁₂ Is converted into correspondingly short pulses (see for U) _Out Graph of (b) which superimposes a further input signal on the first input U _In1 Phase voltage U of _U Sum signal U _Sum In (1). Thereby, the sum signal U _Sum Each fraction U of _Ut 、U _Vt And U _Wt Can be distinguished from each other, thereby using phase signals U _Ut 、U _Vt And U _Wt The speed identification n of the electric motor 30 then requires only one signal line 124 to the evaluating controller 122. In the embodiment according to FIG. 7, the corresponding RC component T is used ₂₁ And T ₂₂ For corresponding input signals U _In3 Adding short pulses, in which the further input signal U _In2 And U _In1 Remain unchanged. In this case, the generated pulses can also be clearly assigned to the respective input signal U _In1 To U _In3 Or U _Ut 、U _Vt And U _Wt 。

For both embodiments of fig. 6 or 7, a non-pulsed input signal U is suitable _In1 To U _In3 Or U _Ut 、U _Vt And U _Wt Always in the same order in time so that they can also be recognized once the input signal has been identified. In principle, it is also possible for the circuit to take into account tolerances or response speeds of the XOR circuit or the gate in order to take account of its pairing at the output U _Out Sum signal U of _Sum And in order to ensure a correspondingly precise speed acquisition of the speed n, the XOR circuit or gate is implemented in the evaluation circuit 80c or 80 d.

In addition to the two embodiments shown, other circuits are also conceivable which deliver at least one of the input signals to the output with a defined characteristic, in particular with a signal pulse extension having a defined length, and which superimpose the other (unmodified) input signals in such a way that it can be inferred later on when evaluating the sum signal which signal edge is caused by which input signal.

Claims (6)

1. For evaluating a phase signal (U) of an electric machine (30) _U 、U _V 、U _W 、I _U 、I _V 、I _W ) Having an input (U) and a device having an input (U) _I2 ) And an output terminal (U) _O2 ) At said input and saidAn operational amplifier (O) is arranged between the output ends, wherein the operational amplifier (O) is applied to the input end (U) _I2 ) Phase signal (U) of (C) _U 、U _V 、U _W 、I _U 、I _V 、I _W ) Generating a triggered phase signal (U) _Ut ) Wherein at the operational amplifier (O) and the output terminal (U) _O2 ) A blocking device (B) is arranged in between in such a way that the triggered phase signal (U) _Ut ) To the output terminal (U) _O2 ) Is transmitted for a duration (Z) ₀ ) Is suppressed, said duration being dependent on a hysteresis mechanism (T),

wherein the blocking device (B) comprises a hysteresis mechanism (T), two switches (F) ₁ 、F ₂ ) And an inverting stage (I),

wherein the hysteresis mechanism (T) has a resistance (R) _b ) And a capacitor (C) _b ）。

2. The device according to claim 1, wherein the capacitance (C) is configured such that _b ) And the resistance (R) _b ) So that said triggered phase signal (U) _UT ) Is at the phase signal (U) _U 、U _V 、U _W 、I _U 、I _V 、I _W ) In the time range around the zero crossing is suppressed.

3. Apparatus according to claim 1, wherein said switch (F) of said blocking device (B) ₁ 、F ₂ ) Is configured as an R/S-flip-flop.

4. The apparatus according to claim 1, followed by an encoding device (80 c, 80 d) for a plurality of phase signals (U) from the motor (30) _U 、U _V 、U _W 、I _U 、I _V 、I _W ) Generating a sum signal (U) _Sum ) Said coding device having at least two inputs (U) _In1 、U _In2 、U _In3 ) At least one of said inputs (U) _In1 、U _In2 、U _In3 ) And the output (U) of the device _O2 ) Connected for exchanging triggered phase signals (U) _UT 、U _VT 、U _WT ) Wherein the encoding device (80 c, 80 d) encodes the triggered phase signal (U) _UT 、U _VT 、U _WT ) And each triggered phase signal (U) is transmitted to the other _UT 、U _VT 、U _WT ) Synthesize the sum signal (U) _Sum ) Wherein the encoding device (80 c, 80 d) adds the sum signal (U) _Sum ) Output to output terminal (U) _Out ) For detecting the rotational speed (n) of the electric motor (30).

5. Apparatus according to claim 4, wherein said coding device (80 c, 80 d) has at least one further hysteresis mechanism (T) ₁₁ 、T ₁₂ ；T ₂₁ 、T ₂₂ ) The hysteresis mechanism can be associated with at least one triggered phase signal (U) of the electric machine (30) _UT 、U _VT 、U _WT ) Said hysteresis mechanism imparting to said at least one triggered phase signal (U) _UT 、U _VT 、U _WT ) And (5) characteristic attributes.

6. The device according to claim 4, wherein the generated output signal (U) _UT 、U _VT 、U _WT ) Or the sum signal (U) generated _Sum ) Is transmitted to a computing unit (122) and is used at the computing unit (122) for determining the rotational speed (n) of a shaft (17) of the internal combustion engine (112).

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