Method and device for processing a signal

0001The present invention relates to a method and an apparatus for processing a signal. In particular, the present invention relates to the processing of a signal while converting a processing time grid.

State of the art

0002The publication "<nplcit id="ncit0001" npl-type="s"><text>Novel Oversampling Techniqu for Improving Signal-to-Quantization Noise Ratio on Acceleromater-Based Smart Jerk Sensors in CNC Application "(Jose J. Rangel-Magdaleon et al., SENSORS, Volume 9, No. 5, May 19, 2009, pages 3767 -3789; ISSN: 1424-8220, DOI 10.3390 / s90503767</text></nplcit>) discloses a method for reducing the signal-to-noise ratio for acceleration-based sensors.

0003The publication <patcit id="pcit0001" dnum="US6906494B2"><text>US 6 906 494 B2</text></patcit> discloses a control device with a sensor for determining the magnetic flux for determining a rotor position. The speed of the rotor is determined from determined positions by means of a differentiating element. This is used as a control variable for a speed controller.

0004Electric and hybrid vehicles are becoming increasingly important. Knowing the rotor position angle of such machines is necessary for controlling permanently excited synchronous machines (PSM) and electrically excited synchronous machines (ESM), such as those used in such vehicles. Knowledge of the electrical frequency of the drive is also required to control asynchronous machines (ASM). To determine the rotor position angle or Different types of sensors can be used for the electrical frequency. For example, sensors based on the eddy current effect, resolvers or digital angle encoders are possible.

0005A resolver is excited, for example, with a preferably sinusoidal carrier signal. The receiver signals of the resolver are usually disturbed, amplitude-modulated voltages, from the envelope of which the information about the rotor position can be obtained.

0006The German patent application <patcit id="pcit0002" dnum="DE102011078583A1"><text>DE 10 2011 078 583 A1</text></patcit> discloses, for example, an evaluation of resolver sensor signals in a vehicle. For this purpose, a resolver sensor records a rotary movement of a rotor, and a processor element processes the sinusoidal or cosine-shaped output signals of the resolver.

0007Due to external conditions, it is possible for a digitized angle signal to be provided by an angle signal generator, such as a resolver, within a processor element in a time grid which differs from the time grid for the further processing of the angle signals. For example, the specifications for an integrated component for evaluating the output signals from an angle signal transmitter may require a calculation grid which does not correspond to the calculation grid for the further processing of the angle signals.

0008There is therefore a need for an apparatus and a method for the efficient processing of angle signals which have been provided with a variable time pattern.

Disclosure of the invention

0009According to a first aspect, the present invention provides an apparatus for processing a signal having the features of independent claim 1.

0010According to a further aspect, the present invention provides a method for processing a signal having the features of independent claim 7.

Advantages of the invention

0011The present invention is based on the idea, when processing signals, in particular when filtering the signals, such as, for example, angle signals from an angular position encoder, to combine this processing with a transition of the computation grid at the same time. For this purpose, the signals are recorded in the original time grid in which the signals were initially made available. This time grid can be determined, for example, by the components for the wiring or the evaluation of the signals from an angle signal generator can be predetermined. In particular, components of this type, such as, for example, integrated circuits or the like, can only be specified for a very specific scanning grid or a predetermined range for a scanning grid. If the further signal processing, such as, for example, the control of a rotary system, in particular an electric drive or the like, is to be carried out in a different time pattern, however, the transition from the first time pattern in which the signals are provided can be carried out in accordance with the present invention the second time grid with which the signals are to be further processed takes place in the course of processing the signals. Such processing of the signals can be filtering of the raw signals, for example. Thus, the filtering of the raw signals can simultaneously result in a transition of the time grid.

0012For the reliable transition of the calculation grid, the input variable does not necessarily have to be sampled significantly faster than the time grid of the output variable requires. It should only be ensured that at least one update of the input variable has taken place between two times of the second time grid.

0013Furthermore, the input variable does not have to be scanned with an equidistant step size. Variable increments are also possible if the increment is known.

0014Since the dynamic part of the processing of the signals is processed with a constant sampling step size after the transition of the calculation grid, approaches of a linear, discrete-time control technique can be used.

0015According to one embodiment, the processing device comprises a PT1 element. PT elements of a higher order are also possible. Furthermore, further dynamic processing of the signals after the transition of the calculation grid is also possible.

0016According to a further embodiment, the differentiating device is designed to subtract a value of a signal detected by the detection device from a value that was previously detected by the detection device. Furthermore, the differentiating device can divide this difference by the difference in the time intervals between the two detected signals. The change in angle thus calculated can be used for further processing and the adjustment of the time grid.

0017According to a further embodiment, the differentiating device is designed to output the differentiated signal to the processing device in a second time pattern. The differentiated signals are thus adapted to the required time grid for further processing.

0018According to a further embodiment, the first scanning grid is variable. In this case, the variable time intervals must be provided on the differentiating device in order to be able to carry out a correct differentiation of the signals. Alternatively, the signal detected by the detection device can also be detected in a predetermined constant time pattern. In this case, knowledge of the predetermined time grid is sufficient for differentiating the signal values.

0019According to a further embodiment, the step for processing the differentiated signal in the method for processing the signal comprises low-pass filtering. In addition, any further processing steps, in particular any filter steps for processing the signal, are also possible. In particular, processing steps are possible that require a predefined time grid.

0020According to a further aspect, the present invention provides a drive system with an electrical machine, a rotation angle sensor and a device according to the invention for processing a signal. The electrical machine is coupled to a drive shaft. Furthermore, the angle of rotation sensor is coupled to the drive shaft. The rotation angle sensor is also designed to provide a signal corresponding to the angular position of the drive shaft.

0021According to a further embodiment, the angle of rotation sensor comprises a resolver.

0022Further embodiments and advantages of the present invention will become apparent from the following description with reference to the accompanying drawings.

Brief description of the drawings

0023Show it:<dl id="dl0001"><dt>Figure 1:</dt><dd>a schematic representation of an electric drive system according to an embodiment;</dd><dt>Figure 2:</dt><dd>a schematic representation of a device for processing a signal according to an embodiment; and</dd><dt>Figure 3:</dt><dd>a schematic representation of a flowchart as it is based on a method according to an embodiment.</dd></dl>

Description of embodiments

0024<figref idref="f0001">Figure 1</figref> shows a schematic representation of an electric drive system according to an embodiment. An electrical machine 3 is fed by an electrical energy source 5 via a converter 4. For example, the electrical energy source 5 can be a traction battery of an electric vehicle. The electrical machine 3 can be, for example, a permanently excited synchronous machine, an electrically excited synchronous machine or else an asynchronous machine. In principle, other electrical machines are also possible. The embodiment of a three-phase electrical machine 3 shown here was only an exemplary embodiment. In addition, electrical machines with a number of phases differing from three are also possible. The power converter 4 converts the electrical energy provided by the electrical energy source 5 and provides the converted electrical energy for controlling the electrical machine 3. The control of the electrical machine 3 can take place based on specifications or control signals from the control device 1. In addition, when the electrical machine 3 is braked, kinetic energy can also be converted into electrical energy by the electrical machine 3 and this electrical energy can be fed via the converter 4 into an electrical energy store of the energy source 5.

0025Knowledge of the position of the rotor in this machine is required to control a permanently or electrically excited synchronous machine. Furthermore, knowledge of the speed of such a machine is necessary for the control of asynchronous machines. For this purpose, the electrical machine 3 can be coupled to a rotation angle transmitter 2. For example, the angle encoder 2 can be coupled to the drive axis of the electrical machine 3. For example, 3 sensors based on the eddy current effect, digital angle sensors or so-called and resolvers are possible for determining the rotor position and / or the speed of the machine.

0026In a resolver, two sensor windings, which are electrically offset by 90 °, are generally arranged in one housing. In principle, various alternatives for determining the angular position are possible, of which one possibility is described below as an example. For example, a further excitation winding of the resolver can be excited with a sinusoidal AC voltage. The amplitudes of the voltages induced in the two sensor windings of the resolver are dependent on the angular position of the rotor and correspond to the sine and cosine of the angular position of the rotor. The angular position of the rotor can thus be calculated from the arctan of the signals of the two sensor windings of the resolver.

0027In addition, the angular position of the rotor can also be detected and made available by any other rotor position sensors. For example, position sensors using an eddy current or digital position signals are also possible.

0028Furthermore, the present invention is not limited to angle signals from an angular position encoder, but can also be applied to any further signals, in particular to further angle-based signals. In principle, it is possible to apply the principle according to the invention to any signal waveforms that are provided or recorded in a first time grid and are then to be processed further in a second, predetermined time grid. The following description with reference to angle signals is therefore not a restriction, but is only intended to provide a better understanding of the invention.

0029<figref idref="f0002">Figure 2</figref> shows a schematic representation of an embodiment for a device for processing a signal curve. First, a signal curve, for example a signal curve of an angle signal, is detected by a detection device 10. This signal curve is recorded in a first sampling rate according to a first time grid. For example, the detection device 10 can be an analog-digital converter that samples a continuous input signal at times according to the first time grid and converts these sampled signal values ​​into digital signal values. The first time grid can be, for example, a fixed time grid with fixed predetermined time intervals between the individual sampling times. In addition, it is also possible to vary the first time grid, that is to say to change the time intervals between two successive samples of the input signal. The adaptation of the first time grid can be specified, for example, by an external control device (not shown). The boundary conditions for the selection of the first time grid in relation to the second time grid for the further processing explained in more detail below are explained in more detail below. The sampled signal values ​​u (t_k) are then together with the times t_k the scanning of a differentiator 20 is provided. The differentiating device 20 receives the sampled signal values ​​u (t_k). If necessary, the differentiating device 20 can have a predetermined number of sampled signal values ​​u (t_k) to save. In this way, the differentiating device 20 can also refer to previous sampled signal values ​​u (t_k) To fall back on. For example, a predetermined number of sampled signal values ​​u (t_k) are buffered in a cyclic memory. Any other type of buffering of signal values ​​is also possible. If the signal values ​​u (t) at the input of the input device 10 are sampled at a fixed predetermined sampling rate, the differentiating device 20 can also know the time intervals of the individual detected signal values ​​u (t_k) close. In this case, the time differences between two successive sampled signal values ​​can be stored permanently in the differentiating device 20. Alternatively, in particular in the case of a variable sampling grid for sampling the input signal on the detection device 10, the respective times t can also be used_kfor which the signal values ​​u (t_k) have been scanned, are transmitted to the differentiating device 20. In this case, the sampling times t_k together with the respective sampled signal values ​​u (t_k) are stored together in a memory of the differentiating device 20. To differentiate the sampled signal values, the differentiating device 20 can form a difference between two sampled signal values ​​and divide this difference by the difference of the sampling times. In this way, the differentiating device 20 calculates a difference quotient which is independent of the sampling time grid.

0030This difference quotient can then be passed on to the processing device 30 in a second time pattern required for further processing in the processing device 30. The input variable at the input of the detection device 10 does not have to be sampled significantly faster than the second time grid of the processing device 30. Rather, it only has to be ensured that an update, that is to say a scanning, is carried out by the detection device 10 between two points in time of the second time grid.

0031After the transition of the difference quotient formed in the differentiating device 20 into the second time grid of the processing device 30, the further processing of the difference quotient takes place in the second time grid of the processing device 30. This further processing of the difference quotient by the processing device 30 can include, for example, filtering, in particular low-pass filtering , For example, the processing device 30 can comprise a PTn element for filtering the angle signal. However, any other processing steps for filtering the angle signal, in particular the difference quotient of the angle signal, are also possible. Since the output of the difference quotient from the differentiating device 20 takes place with the constant step size of the second time grid, any approaches of a linear, time-discrete control technique can be used for the further processing.

0032<figref idref="f0002">Figure 3</figref> shows a schematic representation of a method for processing an angle signal, as based on an embodiment. In a first step S1, an angle signal is first acquired at a first sampling rate in a first time pattern. The detected angle signal is then differentiated in step S2 in the first time grid. For this purpose, as already described above, the difference quotient of the angle signal and sampling times is formed.

0033In step S3, the differentiated angle signal is output in a second time slot and in step S4 the output differentiated angle signal, that is, the difference quotient of the angle signal is processed in the second time slot.

0034As already described above, it should be ensured that at least one update of the sampled angle signal takes place between two points in time in the processing grid for processing the difference quotient.

0035In summary, the present invention relates to signal processing of signals with a simultaneous conversion of the processing time grid. For this purpose, a signal is recorded or provided in a first time grid. After the difference quotient has been formed in the first time grid, the difference quotient is output in a second time grid in which the signal, in particular the difference quotient, is further processed. The signal processing can be applied in particular to angle signals.