DE102011078586A1 - Redundant determination of the rotational movement of an electric machine - Google Patents

Abstract

Circuit (2) for evaluating resolver sensor signals (28) in a vehicle, comprising a resolver sensor (4) configured to receive a rotary movement of a rotor (6) of an electrical machine (16), a resolver digital converter circuit ( 14), communicatively connected to the resolver sensor (4), arranged for driving the resolver sensor (4) and for evaluating the resolver sensor data (28) and a processor element (12), comprising a data connection (24a) to the resolver Digital converter circuit (14) for transmitting evaluated resolver sensor data, characterized in that the processor element (12) has a further data connection (24b) for the transmission of further measurement data for redundant verification of the evaluated resolver sensor data.

Description

The present invention relates to drives for electric or hybrid vehicles. In particular, the present invention relates to a determination of a rotational movement of an electric machine. Furthermore, in particular, the present invention relates to a circuit for evaluating resolver sensor signals in a vehicle, a control device for a vehicle having a circuit according to the invention and a vehicle, in particular an automobile comprising a circuit according to the invention and / or an inventive control device.

State of the art

In electric or hybrid vehicles, a drive power of the vehicle is provided, at least in part, by an electric machine, thus an electric motor. For a preferred control of such an electric machine, it is usually helpful to determine accurate information about the current operating state of the electric machine.

For such a determination is usually a so-called resolver sensor on the electric machine use, which is used to detect rotational speed and angular position of the rotor position of an electric machine.

Speed and angular position are of central importance for motor control. An evaluation logic is used to evaluate the raw data supplied by the resolver sensor in such a way that the required measured variables speed and angular position are provided to a control device, for example as digital data values.

1 shows a conventional resolver sensor with rotor excitation.

At the rotor 6 an electric machine is winding 10a appropriate. This winding is energized with a sinusoidal AC voltage. Two windings mounted vertically on the stator 10b . 10c get one from winding 10a induced voltage.

The amplitudes in the windings 10b . 10c induced voltages is determined by the angle of the rotor or the winding 10a and in each case correspond to the sine and cosine of the angular position of the rotor.

Resolver sensor and Auswertelogik are usually only available.

2 shows a conventional evaluation of a resolver sensor 4 ,

control unit 20 has this microprocessor 12 on, which by means of a reference signal 30 a resolver drive / evaluation circuit 14 , a so-called resolver chip 14 or Resolver Digital Converter Circuit 14 controls. This is exemplarily supplied with a voltage of 5V _dc .

Resolver chip 14 generates an excitation waveform, for example, sine wave with 10 kHz and ± 2.5 V _peak . This sine wave is amplified by element 18 converted into an excitation waveform with ± 10 V _peak and the resolver sensor 4 in winding 10a fed.

Area 26 thus represents the resolver control. Resolver sensor 4 is shown schematically on the engine of an electric machine 16 appropriate.

The resolver sensor data 28 be over filter element 22 , eg a low-pass filter, again the resolver chip 14 as sine or cosine signals, for example with ± 2.85 V _peak supplied.

The resolver chip 14 itself is about data connection 24a with microprocessor 12 connected and provides digital signal values with respect to rotational speed or rotational speed and angular position of the rotor of the electric machine 16 to the microprocessor 12 , Furthermore, the microprocessor 12 via data connection 24a Error information provided.

Although the evaluation logic can include a simple diagnosis of the resolver sensor signals that detects different types of error resolver signals.

However, this error information regularly contains no errors that occur within the resolver chip because they are not sufficiently detectable, or the resolver chip does not have suitable internal precautions in order to be able to check even its proper function.

Thus, errors within the evaluation logic itself as well as the data transfer to a further processing microprocessor of a control unit usually can not be detected. These errors include, for example, register errors, data bit errors, addressing errors of the evaluation logic, frozen data, autonomous reconfiguration of the evaluation logic, as well as arithmetic unit defects, etc.

Such undetectable errors can thus result in the transmission of erroneous speed and angle values, which nevertheless are considered valid by a subsequent control device and can result in a, then faulty, control of the motor. A Such faulty motor control can thus lead to such a faulty control of the electric machine, so that this performs a situation-inadequate rotational movement, or works with an unwanted torque. The risk of "unwanted vehicle movement" or "unwanted vehicle movement direction" can also be caused by a failure of the resolver chip.

Such erroneous activation can, for example, lead to an unwanted acceleration of the vehicle, to the blocking of the drive axle, or even to the destruction of the motor-driving IGBTs.

Disclosure of the invention

One aspect of the present invention can thus be seen to detect errors within the evaluation logic of a resolver sensor as well as in the subsequent data transmission of the evaluated sensor signals from the evaluation logic to a microprocessor, for example a control unit, and thus to avoid dangerous operating states.

In the light of this aspect, a circuit for evaluating resolver sensor signals in a vehicle, a control device for a vehicle having a circuit according to the invention, and a vehicle, in particular an automobile, comprising a circuit according to the invention and / or a control device according to the invention are provided according to the independent claims , Preferred embodiments will be apparent from the dependent claims.

The present invention thus relates to the redundant detection of a rotational speed, a direction of rotation, and angular position or the verification of information supplied by a resolver chip on the basis of further characteristics of a vehicle.

For redundant detection of the rotational speed, for example, one of the analog signals supplied by the resolver sensor can be processed or demodulated by a separate electronic circuit such that a digital frequency signal is generated from the supplied amplitude signal. Such a frequency signal can thus provide the rotor speed via its frequency, at least by means of a rotor speed proportional information.

This rotor speed proportional frequency can be supplied via a further data connection to the microprocessor of a control unit. The microprocessor can then compare this information with the information directly supplied by the resolver chip and thereby detect, for example, a deviation of the two information and thus an error.

If not only one of the signals provided by the resolver sensor, but both analog resolver signals modulated by separate electronic circuits so that two digital frequency signals are generated, the direction of rotation of the rotor can be determined from the phase relationship of the two signals to each other. This information can also be made available to the microprocessor of a control unit via a further data connection in order to verify the correct evaluation of the resolver sensor signals. In this case, an in-phase demodulation of the resolver sensor signals with respect to the reference signal of the microprocessor is used in particular.

As the demodulation circuit, a suitable amplitude demodulation circuit can be used. This can be realized for example by using an amplifier element, a diode element or generally a rectification element, a filter element, in particular low-pass filter element or by means of a Schmitt trigger element. By using a demodulation element, an error in the evaluation logic can be detected by comparing the frequency of the demodulated digital signal with the rotor speed as provided by the resolver chip.

When using two demodulation elements, an error in the evaluation logic can be detected by comparing the frequency of the digital signals with the rotor speed and by comparing the direction of rotation of the digital signals and the sign of the speed of the resolver sensor data.

A calculation of rotational speed, direction of rotation and angular position can also be carried out by means of a further processor element, for example a digital signal processor (DSP), instead of with separate demodulation elements.

For this purpose, a suitable digital signal processor with the two analog resolver sensor signals and the reference signal is applied and thereby forms a separate, redundant data processing and data evaluation. The analog resolver signals together with the reference signal can thus be evaluated in the DSP or in a second microprocessor or else by using a software microprocessor as part of a Complex Programmable Logic Device (CPLD) by appropriate software.

The separate data processing in the DSP or the software used for this purpose, for example, the functionality of the evaluation logic of the resolver chip after and thus independent of and redundant to determine this speed, direction of rotation and angular position.

These second values can now be compared with the values supplied by the resolver chip in order to detect errors in the evaluation logic. The microprocessor, to which both the resolver chip and the separate data processing unit (DSP or CPLD) is connected, can thus detect a difference by comparing the rotational speed values, the direction of rotation, for example signs of the rotational speed, and by comparing the angle values thus discovering an error.

However, the verification of the proper functioning of a resolver chip can also be provided by further vehicle data that is not supplied by the resolver sensor. In particular, a speed can be checked using an external control unit.

For this purpose, in particular, a speed mechanically correlated with the electrical machine speed can be measured by another control unit by a separate sensor system. Usable is, for example, the wheel speed supplied by an ESP or ABS control unit with the connected via a fixed gear electric machine or even the engine speed of the engine, supplied by the engine control unit. Such rotational speed information can subsequently be forwarded to the engine control unit of the electrical machine via a communication interface, for example via a CAN bus or FlexRay.

By a subsequent comparison of the Resolver sensor speed supplied by the resolver chip with the externally measured speed, the speed value of the resolver chip can be checked for its correctness or plausibility.

Embodiments of the invention are illustrated in the drawings and explained in more detail in the following description.

Show it

1 a resolver sensor;

2 an exemplary embodiment of a circuit of resolver sensor and resolver evaluation logic;

3a , b is an exemplary embodiment of an arrangement for the redundant evaluation of the resolver sensor signals;

4a b shows another exemplary embodiment of a redundant resolver sensor signal evaluation according to the present invention;

5 a further exemplary embodiment of a redundant resolver sensor signal evaluation according to the present invention; and

6 an exemplary embodiment of a verification of the resolver sensor signal evaluation.

Embodiments of the invention

Further referring to 3a , b shows an exemplary embodiment of an arrangement for the redundant evaluation of the resolver sensor signals.

3a shows central resolver chip 14 as well as a schematic resolver sensor 4 , Using the amplifier element 18 with Gain G controls resolver chip 14 via reference signal 30 the resolver sensor 4 at.

Due to the above-described functionality of the resolver sensor 4 become two amplitude modulated analog signals 28 to the evaluation element 22 , exemplified here as two amplifier elements with gain G, passed on and back into the resolver chip 14 recycled. Resolver chip 14 evaluates the resolver signals 28 and derives them as digital information on speed and angular position using the data link 24a via a data bus to microprocessor 12 further. One of the two signals supplied by the resolver 28 is tapped in parallel and the demodulation element 32a fed.

In particular, a demodulation element in the context of the present invention may be a normal frequency demodulation circuit. This can e.g. be implemented as an amplifier element, a diode, a rectifier circuit, a low-pass filter or a Schmitt trigger element.

demodulation 32a converts the analog resolver signal 28 represented in 3b as amplitude-modulated sine or cosine oscillation, in a digital square-wave signal, also in 3b represented, and passes this over data connection 24b to the microprocessor 12 further. This has, for example, a General Purpose Timing Ray, which can evaluate the demodulated or digitized resolver signal with respect to its frequency, pulse width, period, etc. In particular, by evaluating the frequency or the period can be at a speed of the rotor 6 Close the electric machine.

Further referring to 4a . 4b A further exemplary embodiment of a redundant resolver sensor signal evaluation according to the present invention is shown.

The arrangement of 4a This corresponds essentially to the arrangement of 3a but with two demodulator elements 32a . 32b each connected to one of the resolver signals 28 are provided. The operation of each demodulator element 32a . 32b is essentially the same as described above.

Each demodulator element 32a . 32b generates a digital square wave signal from the amplitude modulated analog signal of the resolver sensor 4 which, however, are shifted from one another by a fraction of a period, in particular by half a period. From the period of the digital signals and thus from their frequency can in turn close to the rotor speed, while the direction of rotation of the digital signals and the sign of the speed of the resolver evaluation can be removed.

Further referring to 5 A further exemplary embodiment of a redundant resolver sensor signal evaluation according to the present invention is shown.

5 has another processor element 34 on, for example, a digital signal processor. Both analogue resolver sensor signals 28 as well as the reference signal 30 be in the other microprocessor 34 fed. This is about the further data connection 24b also with microprocessor 12 connected.

In the digital signal processor, for example, the functionality of a resolver chip can now be simulated in software. Thus, information comparable to those, the resolver chip 14 via the data connection 24a to the microprocessor 12 supplies, also from the digital signal processor 34 via data connection 24b to microprocessor 12 be passed on. Through a simple comparison of data connections 24a and 24b data supplied with respect to speed, direction of rotation and angular position may indicate proper operation of resolver chip 14 and microprocessor 34 getting closed.

Further referring to 6 an exemplary embodiment of a verification of the resolver sensor signal evaluation is shown.

Essentially done in 6 a known resolver sensor evaluation comparable to 2a , which information regarding speed, direction of rotation and angular position using the data link 24a to microprocessor 12 passes.

Via data connection 24b receives microprocessor 12 further information from other control units 36a , b, for example, an ESP control unit 36a or an engine control controller 36b , These other values can be, for example, the wheel speed of the ESP control unit 36a or the speed of an internal combustion engine engine control unit 36b be.

This information can be shared with the resolver chip 14 supplied information from the microprocessor 12 considered and thus checked for plausibility. For example, information from the ESP controller 36a about the standstill of the wheels and the information of the resolver chip 14 After which the rotor 6 an electric machine 16 would turn on an error or a faulty evaluation in the resolver chip 14 clues.

Claims (10)

Circuit ( 2 ) for evaluating resolver sensor signals (10) in a vehicle, comprising a resolver sensor (10) 4 ) arranged to receive a rotational movement of a rotor ( 6 ) an electric machine ( 16 ); a Resolver to Digital Converter Circuit (RDC) ( 14 ), communicatively connected to the resolver sensor ( 4 ), set up to drive the resolver sensor ( 4 ) and for evaluating the resolver sensor data ( 28 ); and a processor element ( 12 ), having a data connection ( 24a ) to the resolver-to-digital converter circuit ( 14 ) for transmission of evaluated resolver sensor data; characterized in that the processor element ( 12 ) another data connection ( 24b ) for transmitting further measurement data for redundant verification of the evaluated resolver sensor data. The circuit of claim 1, wherein the further measurement data also includes the resolver sensor data ( 28 ) are. A circuit according to claim 1 or 2, wherein the resolver sensor ( 4 ) is arranged to output at least one sinusoidal or cosinusoidal amplitude-modulated analogue signal ( 28 ); wherein a demodulator element ( 32a , b) at the further data connection ( 24b ) and that is at least one analog signal ( 28 ) parallel to the resolver-to-digital converter circuit ( 14 ) receives; and wherein the demodulator element ( 32a , b) is set up, a conversion of the analog signal ( 28 ) in a speed-proportional digital frequency signal and to the processor element ( 12 ) forward. Circuit according to one of the preceding claims, wherein the resolver sensor ( 4 ) is arranged to output a sinusoidal and a cosinusoid amplitude modulated analog signal ( 28 ); wherein two demodulator elements ( 32a , b) at the further data connection ( 24b ) and each demodulator element ( 32a , b) one of the two analog signals ( 28 ) parallel to the resolver-to-digital converter circuit ( 14 ) receives; each demodulator element ( 32a , b) a conversion of the respective analogue signal ( 28 ) in a speed-proportional digital frequency signal and to the processor element ( 12 ) forward; and wherein the processor element ( 12 ) is set, a direction of rotation of the rotor ( 6 ) of the electric machine ( 16 ) based on the phase relationship of the digital frequency signals to each other. Circuit according to one of claims 3 or 4, wherein the demodulator element ( 32a , b) an element is selected from the group consisting of amplifier element, rectifier element, diode element, filter element, low-pass filter element and Schmitt trigger element. Circuit according to one of claims 1 or 2, wherein the resolver sensor ( 4 ) is arranged to output a sinusoidal and a cosinusoid amplitude modulated analog signal ( 28 ); the resolver to digital converter circuit ( 14 ) a reference signal ( 30 ) for controlling the resolver sensor ( 4 ) provides; wherein another processor element ( 34 ) at the further data connection ( 24b ) and the two analogue signals ( 28 ) parallel to the resolver-to-digital converter circuit ( 14 ) as well as the reference signal ( 30 ) receives; and wherein the further processor element ( 34 ), the analog signals ( 28 ) as well as the reference signal ( 30 ) evaluate such that the speed, direction of rotation and angular position of the rotor ( 6 ) of the electric machine ( 16 ) and this information to the processor element ( 12 ) forward. A circuit according to claim 1, wherein the further measurement data includes data from the resolver sensor ( 4 ) separate sensor or separate control unit ( 36a , b) of the vehicle. The circuit of claim 7, wherein the data is selected from the group consisting of wheel speed of an ESP or ASB controller, engine speed of an engine control unit; and / or wherein the processor element ( 4 ) is set up a plausibility comparison of the other measured data with the data of the resolver-digital converter circuit ( 14 ), in particular for the redundant verification of the evaluated resolver sensor data ( 28 ). Control unit ( 20 ) for a vehicle, comprising a circuit ( 2 ) according to one of the preceding claims. Vehicle, in particular automobile, having a circuit ( 2 ) according to one of claims 1 to 8 and / or a control device ( 20 ) according to claim 9.

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