Search

EP-4741841-A1 - METHOD, CALIBRATION AND MEASUREMENT DEVICE FOR DETERMINING A MEASURED VALUE

EP4741841A1EP 4741841 A1EP4741841 A1EP 4741841A1EP-4741841-A1

Abstract

To reduce measurement errors, a setup comprising an input sensor ( S1 ) for measuring an input quantity ( u1 ) of a technical system (2) and for outputting an input sensor response ( SA1 ), an input conversion unit ( W1 ) for converting the input sensor response ( SA1 ) into an input measurement ( y1 ), an output sensor ( S2 ) for measuring an output quantity ( u2 ) of the technical system (2) and for outputting an output sensor response ( SA2 ), and an output conversion unit ( W2 ) for converting the output sensor response ( SA2 ) into an output measurement ( y2 ), is comprehensively performed during a time-based calibration period in which the technical system (2) is in a calibration state. During this period, an input measurement ( y1 ) and an output measurement ( y2 ) are acquired and compared to generate a calibration reference value ( ey ). The input conversion unit (W 1 ) is corrected to a corrected input conversion unit (W 1 ) depending on the calibration reference value (e y ), and in a temporal active section in which the technical system (2) is in an active state different from the calibration state, the corrected input conversion unit (W 1 ) is used to measure the input quantity (u 1 ).

Inventors

  • Pumberger, Michael
  • Matzer, Martin

Assignees

  • AVL List GmbH

Dates

Publication Date
20260513
Application Date
20251104

Claims (15)

  1. Method for determining a measured value (y 1 , y 2 ), wherein the following are provided - an input sensor (S 1 ) for measuring an input quantity (u 1 ) of a technical system (2) and for outputting an input sensor response (SA 1 ) as a function of the input quantity (u 1 ), - an input conversion unit (W 1 ) for converting the input sensor response (SA 1 ) into an input measured value (y 1 ), - an output sensor (S 2 ) for measuring an output quantity (u 2 ) of the technical system (2) and for outputting an output sensor response (SA 2 ) as a function of the output quantity (u 2 ), - an output conversion unit (W 2 ) for converting the output sensor response (SA 2 ) into an output measured value (y 2 ), characterized in that, during a calibration period in which the technical system (2) is in a calibration state, an input measurement ( y1 ) and an output measurement ( y2 ) are acquired and compared to generate a calibration reference value ( ey ), that the input conversion unit ( W1 ) is corrected to a corrected input conversion unit ( W1 ) depending on the calibration reference value ( ey ), and/or the output conversion unit ( W2 ) is corrected to a corrected output conversion unit ( W2 ) depending on the calibration reference value ( ey ), and that, during an active period in which the technical system (2) is in an active state different from the calibration state, the corrected input conversion unit ( W1 ) is used to measure the input quantity ( u1 ), and/or the corrected The output conversion unit (W 2 ) is used to measure the output quantity (u 2 ).
  2. Method according to claim 1, characterized in that the input conversion unit (W 1 ) has a converter gain to convert the input sensor response (SA 1 ) into the input measured value (y 1 ) and/or the output conversion unit (W 2 ) has a converter gain to convert the output sensor response (SA 2 ) into an output measured value (y 2 ), and that the converter gain is increased or decreased for correction depending on the calibration reference value (e y ).
  3. Method according to one of the preceding claims, characterized in that the input variable (u 1 ) is determined according to a state of the technical system (2) the specified transmission ratio of the technical system (2) is related to the output variable (u 2 ), wherein the transmission ratio in the calibration section corresponds to a predetermined constant transmission ratio and in the active section corresponds to a variable transmission ratio.
  4. Method according to one of the preceding claims, characterized in that in the calibration section an input measurement profile (yt1) comprising a plurality of input measurement values (y 1,k , y 1,k+1 , y 1,k+2 , ...) and an output measurement profile (yt2) comprising a plurality of output measurement values (y 2,k , y 2,k+1 , y 2,k+2 , ...) are recorded and compared with each other in order to generate the calibration comparison value (e y ).
  5. Method according to claim 4, characterized in that the input measurement profile (yt1) is filtered by means of an input measurement filter (F1) before comparison with the output measurement profile (yt2) and/or that the output measurement profile (yt2) is filtered by means of an output measurement filter (F2) before comparison with the input measurement profile (yt2) and/or that a time profile of calibration comparison values (e y ) is filtered by means of a comparison filter (F3) before use for correction of the input conversion unit (W 1 ).
  6. Method according to claim 5, characterized in that the input measurement filter (F1) and/or the output measurement filter (F2) and/or the comparison filter (F3) is implemented in the form of a low-pass filter or in the form of a high-pass filter or in the form of a band-pass filter or in the form of a mean value filter or in the form of a maximum filter or in the form of a minimum filter or in the form of an absolute value calculation or in the form of a scaling factor or in the form of a combination of the aforementioned filters.
  7. Method according to one of the preceding claims, characterized in that the calibration comparison value (e y ) is compared with a predetermined plausibility value to perform a plausibility check and that, if the calibration comparison value (e y ) exceeds or falls below the plausibility value, a safeguard action is triggered.
  8. Method according to one of the preceding claims, characterized in that a switchable mains rectifier (2) is provided as a technical system (2) with a mains-side AC voltage as input variable (u 1 ) and a DC intermediate circuit voltage as output variable (u 2 ) or that an electric motor is provided as a technical system (2) with an AC phase current as input variable (u 1 ) and a torque generated by the electric motor as output variable (u 2 ) or that an internal combustion engine is provided as a technical system (2) with an accelerator pedal position as input variable (u 1 ) and a crankshaft torque as output variable (u 2 ) or that a powertrain test bench is provided as a technical system (2) with a load torque as input variable (u 1 ) and a test specimen speed as output variable (u 2 ).
  9. Method according to claim 8, characterized in that a switchable mains rectifier (2) having switchable semiconductor switches (T a1 , T a2 , ...) is provided as a technical system (2), wherein a calibration state of the mains rectifier (2) is provided in which the semiconductor switches (T a1 , T a2 , ...) present in the mains rectifier (2) are open and are not switched, and wherein an active state of the mains rectifier (2) is provided in which the semiconductor switches present in the mains rectifier (2) are switched in order to regulate a DC intermediate circuit voltage output by the mains rectifier (2) to a predetermined intermediate circuit voltage setpoint.
  10. Method according to claim 9, characterized in that an intermediate circuit capacitor (C 0 ) is provided at the output of the switchable mains rectifier (2), across which the DC intermediate circuit voltage drops, and that a time period is selected as the calibration period in which the intermediate circuit capacitor (C0) is charged and preferably not loaded.
  11. A method according to one of claims 8 to 10, characterized in that a switchable mains rectifier (2) is provided as a technical system (2) and the switchable mains rectifier (2) is provided as part of a battery emulator (1) or as part of a battery tester, wherein the mains rectifier (2) is connected on an input side of the mains rectifier (2) to an AC supply network which provides a mains-side AC voltage for the mains rectifier (2) and is connected on an output side of the mains rectifier (2) to an intermediate circuit capacitor (C 0 ) for stabilizing a DC intermediate circuit voltage (U 0 ) output by the mains rectifier (2), wherein the intermediate circuit capacitor (C 0 ) is further connected to a DC voltage converter (3) to convert the DC intermediate circuit voltage (U 0 ) into an output voltage (u A ).
  12. Method according to claim 11, characterized in that a PI controller or a PID controller or a sliding-mode controller or backstepping controller or a model-based control with a model of the grid rectifier (2) is used for controlling the grid rectifier (2), wherein measured values of the grid-side AC voltage are used as input measured value (y 1 ) and measured values of the DC intermediate circuit voltage (U 0 ) are used as output measured value (y 2 ) in the control.
  13. Calibration device for calibrating an input conversion unit ( W1 ) and/or an output conversion unit ( W2 ), wherein the calibration device is configured to compare an input measurement value ( y1 ) and an output measurement value ( y2 ) in order to generate a calibration reference value ( ey ) and to correct the input conversion unit ( W1 ) to a corrected input conversion unit ( W1 ) depending on the calibration reference value ( ey ) and/or to correct the output conversion unit ( W2 ) to a corrected output conversion unit ( W2 ) depending on the calibration reference value ( ey ), wherein - the input measured value (y 1 ) can be generated by an input sensor (S 1 ) measuring an input quantity (u 1 ) of a technical system (2) which is in a calibration state and outputting an input sensor response (SA 1 ) as a function of the input quantity (u 1 ) and the input conversion unit (W 1 ) converting the input sensor response (SA 1 ) into the input measured value (y 1 ), - the output measured value (y 2 ) can be generated by an output sensor (S 2 ) measuring an output quantity (u 2 ) of the technical system (2) in the calibration state and outputting an output sensor response (SA 2 ) as a function of the output quantity (u 2 ) and the output conversion unit (W 2 ) converting the output sensor response (SA 2 ) into the output measured value (y 2 ).
  14. Measuring device for determining a measured value (y 1 , y 2 ), comprising - an input sensor (S 1 ) for measuring an input quantity (u 1 ) of a technical system (2) and for outputting an input sensor response (SA 1 ) as a function of the input quantity (u 1 ), - an input conversion unit (W 1 ) for converting the input sensor response (SA 1 ) into an input measured value (y 1 ), - an output sensor (S 2 ) for measuring an output quantity (u 2 ) of the technical system (2) and for outputting an output sensor response (SA 2 ) as a function of the output quantity (u 2 ), - an output conversion unit (W 2 ) for converting the output sensor response (SA 2 ) into an output measured value (y 2 ), - a calibration device according to claim 13, which is configured to provide an input measurement value (y 1 ) and an output measurement value (y 2 ) which, in a time-based calibration period in which the technical system (2) is in a calibration state, to be recorded, read in and compared with each other in order to generate a calibration reference value (e y ), and to correct the input conversion unit (W 1 ) as a function of the calibration reference value (e y ) to a corrected input conversion unit (W 1 ) and/or to correct the output conversion unit (W 2 ) as a function of the calibration reference value (e y ) to a corrected output conversion unit (W 2 ) in order to measure the input quantity (u 1 ) using the corrected input conversion unit (W 1 ) and/or the output quantity (u 2 ) using the corrected output conversion unit (W 1 ) in a temporal active section in which the technical system ( 2 ) is in an active state different from the calibration state.
  15. Measuring device according to claim 14, wherein a mains rectifier (2) is provided as a technical system (2).

Description

The present invention relates to a method for determining a measured value, wherein an input sensor for metrologically acquiring an input variable of a technical system and for outputting an input sensor response as a function of the input variable, an input conversion unit for converting the input sensor response into an input measured value, an output sensor for metrologically acquiring an output variable of the technical system and for outputting an output sensor response as a function of the output variable, and an output conversion unit for converting the output sensor response into an output measured value are provided. The invention further relates to a calibration device and a measuring device. Power converter assemblies are known in a wide variety of designs and are used in a multitude of different applications. For example, electric and hybrid vehicle drives incorporate power converter assemblies to convert the direct current (DC) voltages supplied by batteries into suitable alternating current (AC) voltages. These AC voltages are then applied to the electrical machines to be driven. Power converter assemblies typically comprise combinations of rectifiers (AC/DC converters), inverters (DC/AC converters), and/or converters (DC/DC converters, AC/AC converters, boost converters, buck converters). To test modern drive concepts that are at least partially based on electric motors, series topologies consisting of AC/DC converters, DC/DC converters, and DC/AC converters are typically used. A AC/DC converter first generates a DC link voltage from a generally multi-phase AC supply voltage (mains AC voltage). This DC link voltage can then be adjusted to a suitable voltage level by a downstream DC/DC converter (boost converter, buck converter). When using active and therefore switchable AC/DC converters ("synchronous rectifiers"), a separate downstream DC/DC converter can be omitted, and a regulated and thus appropriately adapted DC link voltage can be provided directly by the AC/DC converter. A DC voltage generated in this way, with an adjusted voltage level, can be converted into a suitable AC voltage using an inverter if AC voltages are required for testing, for example, an AC voltage for each phase of an AC electric motor under test. The DC or AC voltages obtained in this way are then applied, for example, to the stator windings of an electric motor under test to generate the necessary phase current for generating torque and/or to effect rotational speeds. Corresponding structures are well known from the prior art, e.g. from AT 523580 B1 or from EP 2 855 193 B1 . In the aforementioned applications with series topologies of rectifiers and inverters, it is necessary to precisely regulate the DC link voltage to a predefined setpoint to ensure satisfactory operation of a downstream inverter that further processes the DC link voltage. For this purpose, highly accurate and high-resolution sensors are usually used to measure the DC link voltage. However, in the case of using active rectifiers to convert mains AC voltage into a regulated DC link voltage, the above statements also apply to measuring the mains AC voltage applied to the rectifier on the mains side. If a mains AC voltage is measured incorrectly, and a controller for regulating the DC link voltage—and thus for switching the rectifier's semiconductor switches—receives incorrect information about the mains AC voltage, the control performance will obviously deteriorate, accuracy will be lost, and sometimes even stability problems will occur. This is referred to as a reduced quality of the "AC-side network control". In the scenario described above, the calibration and adjustment of AC measurement chains regularly pose problems. It is well known that AC sensors and their corresponding measurement chains must be checked and, if necessary, calibrated and/or adjusted at regular intervals, for example, during commissioning to compensate for component variations, or during operation to compensate for aging effects and/or component drift. Calibration and correction of DC measurement chains are typically possible with minimal effort and without special technical equipment, allowing DC measurement chains for the intermediate circuit voltage to be precisely adjusted, e.g., during operational breaks or even during operation, to meet the required accuracy standards. However, this is not the case for AC measurement chains used to measure mains-side AC voltages. In fact, the calibration process for AC quantities is significantly more complex than for DC quantities. This is partly due to the more complex time-dependent responses of AC quantities (high voltages result in high signal gradients and high signal amplitudes), which necessitates more complex measurement chains for signal processing. On the other hand, particularly in cases with high electrical power, it is difficult to generate suitable comparison signals whose signal parameters are known and which can be co