JP6462995B2 - Method and apparatus for output control or voltage control - Google Patents

Description

  The present invention is a method for output control or voltage control to supply an electrical consumer using an output final stage, wherein the output control or voltage control is a pulse having an adjustable on / off ratio. The present invention relates to a method performed via width modulation (PWM).

  The present invention is also an apparatus for output control or voltage control to supply an electrical consumer using an output final stage, the output control or voltage control having an adjustable on / off ratio. The present invention relates to a type in which a control unit is provided in the output final stage, which is performed through pulse width modulation (PWM).

  It is known to control an electrical consumer via pulse width modulation (PWM) to regulate the output, effective voltage or effective current. In this case, for example, a constant supply voltage of the electrical consumer is switched on and off within a predetermined on / off ratio (TV). Through the ratio of the switch on time to the switch off time, the power, effective voltage and effective current supplied to the consumer are adjusted.

  The on / off operation can be performed via a correspondingly controlled output final stage. In this case, the on / off ratio can be adjusted or controlled and preset.

  The adjustment of the on / off ratio is made in a controlled system based on the ideal characteristics of the electronic components used and thus on the assumption of temporal changes in the voltage supplied to the consumer. Deviations from the ideal characteristics of the output final stage, for example due to limited cut-off characteristics or delay times, directly affect the output supplied to the consumer or the effective current and effective voltage. Such deviation may be due to the response characteristics of the used electronic component, which in some cases varies with component tolerances. Cut-off characteristics may additionally be limited by requirements related to electromagnetic compatibility (EMV).

  Deviations from ideal characteristics are particularly significant at low on / off ratios with pulse width modulation. A small on / off ratio can be obtained, for example, by operating the electric consumer with various supply voltages. Patent Document 1 describes a method for controlling an actuator in a battery circuit system having various operating voltages or temporal battery voltage changes. In this case, the actuator or actuators are controlled by various control signals that are pulse width modulated, and the pulse width and period of the control signals can be adjusted independently of each other, so that the actual battery voltage can be adjusted. Adapted based on.

  Exhaust gas measuring probes such as lambda sensors, such as those used today in modern internal combustion engines to monitor and control exhaust gas composition, are often used in exhaust gas measuring probes, for example in the range of 800 ° C. It has an electric heater for adjusting a predetermined operating temperature. The heating output is adjusted by, for example, pulse width modulation set to 12V supply voltage. When using an exhaust gas measurement probe in a 24V system, a very small on / off ratio results. Deviations from ideal characteristics of the pulse width modulation are corrected by the thermostat after reaching a predetermined target temperature during the control operation. During control operation, for example, while measurements are not provided for control from an exhaust gas measuring probe, deviations from such ideal characteristics carry a correspondingly high risk of causing malfunctions due to malfunctions, Large temperature shifts may occur.

  In another mode of operation, so-called overheating prevention, the lambda sensor is adjusted to a low target temperature in the range of 100 ° C. to 200 ° C. during the heating phase. The overheating prevention is performed to evaporate water existing inside or outside the lambda sensor and in the exhaust gas passage. This reduces the risk of damage to the ceramic of the sensor element of the lambda sensor due to too high thermomechanical stress in the subsequent heating process with a high effective heater voltage. In order to maintain a predetermined target temperature sufficiently accurately, it is necessary to accurately adjust the effective voltage applied to the heater. For this reason, today, the on / off ratio of the voltage applied to the heater is determined from the value of the supply voltage measured in the control device and the desired effective voltage at the heater resistance. Calculated assuming a signal. In this case, a very small on / off ratio in the range of 0.5-2% is obtained to prevent overheating. Due to the deviation of the voltage change from the ideal rectangular wave change, a deviation between the target value and the actual value of the effective voltage applied to the heater occurs. This results in an unacceptably large lambda sensor temperature from the target temperature at the required small on / off ratio.

  In order to allow controlled operation even at small on / off ratios, a fast (in the sense of high cut-off characteristics, short delay times), narrow tolerance output final stages can be used for control. However, this results in unacceptably high EMV radiation as well as expensive component costs.

  Another possibility is to use a DC / DC converter instead of pulse width modulation. This results in manufacturing costs that are too expensive. Another drawback is the large required space for the DC / DC converter as well as the high heat loss that occurs when carrying out the method.

  Similarly, in measuring and adjusting the appropriate current intermediate value or current effective value, there is an expensive cost and high space requirements, as well as expensive hardware costs.

German Patent Publication No. 102010001004

  Therefore, an object of the present invention is to provide a method for enabling voltage control or output control of an electric consumer accurately and inexpensively through pulse width modulation even at a small on / off ratio.

  Another object of the present invention is to provide a corresponding device.

  This task is achieved according to the invention by determining one measured effective voltage at each of the consumers in the measurement phase under various operating conditions described by at least two operating parameters of the output final stage, and the pulse width. The modulation on / off ratio is changed so that the measured effective voltage corresponds to the preset effective target voltage, and the calculated on / off ratio is related to the operating conditions to which it belongs. This is solved by memorizing and calculating the modified on / off ratio from the memorized on / off ratio and adjusting for output control or voltage control in the application phase for the current operating conditions. The The determination of the measured effective voltage is made during the measurement phase with an appropriate time resolution, so that the voltage change over all switch-on pulses is calculated, from which the measured effective voltage at the consumer is determined. Is done. In this case, the measurements can be made individually for each output final stage, or preferably for a predetermined portion of the output final stage for one production run. During the application phase in normal operation, voltage measurement at the consumer is no longer necessary. The modified on / off ratio is calculated from the stored on / off ratio, and interpolation with large data maps is avoided, so the modified on / off ratio can be determined quickly and at low hardware costs . The corrected on / off ratio takes into account the deviation of the actual voltage change from the ideal square wave change while additionally taking into account the influence of the operating conditions at that time, so that the predetermined effective voltage is small The / off ratio can also be adjusted accurately.

  According to a particularly preferred variant of the invention, the dependence of the calculated on / off ratio on the various operating parameters is adapted to calculate a modified on / off ratio. At least approximately described by a fitted mathematical function having the function and the coefficients of the membership are memorized and having the memorized functions and the memorized coefficients in the application phase for the current operating parameter It may be set such that a modified on / off ratio is determined. In order to calculate a modified on / off ratio, only functions and coefficients need to be stored, which provides a very small memory requirement. A mathematical function calculation can determine the on / off ratio very quickly based on the actual operating conditions under which the output final stage is operated. The mathematical function can be determined from the calculated dependence of the on / off ratio on various operating conditions affecting the voltage change, for example by means of a corresponding Fit-Function or by regression analysis.

  When considering two operating parameters when modifying the on / off ratio, to calculate the modified on / off ratio, for the various values of the second operating parameter of the calculated on / off ratio. The dependence on the first operating parameter is at least approximately described by a first mathematical function and a first theorem of the first coefficient to which it belongs, and the second coefficient of the first coefficient Dependence on the parameter is described at least approximately by a second theorem of the second mathematical function and the second coefficient of the belonging, the second coefficient and the mathematical function being stored in memory, A first coefficient belonging to the current second operating parameter is determined in an application stage for the current second operating parameter having the determined second coefficient and a second mathematical function, The first factor and By the first mathematical function, and it may be set as modified on / off ratio for the currently first operating parameter is calculated.

  Therefore, only the first and second functions and the second coefficient need be stored. In this case, the dependence of the calculated on / off ratio on the first operating parameter for the various values of the second operating parameter is approximated by a common function, each having a first coefficient adapted. It is assumed that it can be done. Therefore, it is necessary to determine a second mathematical function, and using this second mathematical function, by adapting the second coefficient, the first coefficient to the second operating parameter is determined. Dependencies can be described. In this case, the first theorem of the first mathematical function is obtained from the first mathematical function and the respective first coefficients fitted. The second theorem of the second mathematical function is obtained from the second mathematical function and the second coefficient respectively adapted.

  Therefore, the on / off ratio thus modified takes into account the effect of the first and second operating parameters on the resulting voltage change.

  The modification of the effect of any number of operating parameters on the on / off ratio is corrected by determining other theorems for other functions and other factors of membership for each other operating parameter. obtain.

  In this case, the dependence of the coefficients determined for the operating parameters considered in advance for various values of the other operating parameters depends on the other mathematical functions and other theorems of the other coefficients belonging. Other coefficients and other mathematical functions are memorized at least approximately, and the coefficients determined for the operating parameters previously considered in the application phase for the actual values of the other operating parameters May be set to be determined.

  A simple determination of the effective voltage at the consumer can be obtained by digitally detecting the voltage change at the consumer during the measurement phase and determining the measured effective voltage at the consumer from this voltage change. it can. In this case, the detection can be performed via a correspondingly fast analog / digital converter, so that an edge change deviating from the rectangular wave shape can be formed. Since the determination of the voltage change is made only during the measurement phase, the control unit does not have to have a corresponding analog / digital converter. The determination of the voltage change can be carried out at the corresponding measurement points for each output final stage.

  Deviations of the voltage from the ideal square wave shape due to limited cut-off characteristics or delay times have a strong effect on the effective voltage, especially at small on / off ratios. Thus, the on / off ratio modification may be set to be performed at an on / off ratio of less than 5%, in particular an on / off ratio of less than 2%. No correction is made at large on / off ratios. The function and coefficient determination need only be made for reasonably small on / off ratios.

  Parameters that control the switch characteristics of the output final stage, such as the cut-off characteristics or delay time, are generally strongly influenced by the temperature and supply voltage of the output final stage. Furthermore, the switch characteristics can also be affected by degradation effects. Therefore, at least the temperature of the output final stage and / or the value of the supply voltage and / or the deterioration of the output final stage may be set to be considered as operation parameters.

  The dependence of the calculated on / off ratio or factor on important operating parameters, in particular supply voltage and temperature, often follows the characteristics of a second order polynomial. Therefore, a quadratic polynomial is used as a function to describe the dependence of the calculated on / off ratio on the operating parameters and / or the dependence of the coefficients on the operating parameters. It may be set as follows.

  The calculated on / off ratio and coefficient dependence may be based on a preset effective target voltage. Thus, when the consumer is operated at different effective voltages, the coefficients and / or functions may be set to be determined for different effective target voltages, respectively.

  The object of the present invention with respect to the device is that the control unit has a memory for storing functions and associated coefficients for describing the dependency of the modified on / off ratio on the operating parameters of the output final stage. The control unit has at least one program sequence for calculating a modified on / off ratio for the actual value of the operating parameter using the stored coefficients and functions , Solved by that. This device makes it possible to carry out the method.

  This method and apparatus is preferably used for output control of an electric heater of an exhaust gas sensor in an exhaust gas passage of an internal combustion engine or for voltage control.

  The present invention will be described in detail below with reference to embodiments shown in the drawings.

It is a circuit diagram which shows the electric circuit for the output control of an electric consumer. It is a diagram showing a signal change of pulse width modulation in a short switch-on time. It is a diagram which shows the 1st change of the calculated on / off ratio. FIG. 5 is a diagram illustrating a first change in a first coefficient related to temperature. It is a diagram which shows the 2nd change of the calculated on / off ratio. It is a diagram which shows the 3rd change of the calculated on / off ratio. It is a diagram which shows the 4th change of the calculated on / off ratio. FIG. 6 is a diagram showing a second change in the fitted coefficient.

  FIG. 1 shows an electrical circuit for output control of an electrical consumer 10 according to the prior art. In this embodiment, the electric consumer 10 corresponds to an electric heater of a lambda sensor in the exhaust gas passage of the internal combustion engine.

  The supply voltage is supplied by a power supply 14 which is installed on the ground 15 on one side.

  The electric circuit has a control unit 11, and an output final stage 12 and a TV calculator 13 are arranged in the control unit 11. The output final stage 12 is configured in the form of an NMOS field effect transistor (FET) having a drain connection 12.1, a source connection 12.2, and a gate connection 12.3. Source connection 12.2 is connected to the ground connection of power supply 14. The drain connection 12.1 is connected to the consumer 10 and the gate connection 12.3 is connected to the TV calculator 13. The power source 14 is connected to the control unit 11, and one side is connected to the consumer 10.

  In order to control the power supplied to the consumer 10, a pulse width modulation signal (PWM signal) is applied to the gate connection 12.3. During the switch on time of the PWM signal, the field effect transistor is connected and current flows from the power supply 14 through the consumer 10 and the output final stage 12 to the ground 15. The current is cut off during the switch-off time. The output converted in the consumer 10 is preset via the on / off ratio TV of the PWM signal. In this case, the on / off ratio TV is determined by the TV calculator 13 in consideration of the supplied supply voltage. The gate connection 12.3 is controlled by the TV calculator 13 such that a preset effective voltage is applied to the consumer 10.

  Corresponding to the illustrated configuration of the electric circuit, the output final stage 12 is configured as a low-potential side switch leading to the ground 15 in this embodiment.

  FIG. 2 shows the signal change of the pulse width modulation with a shorter switch-on time as obtained in the exhaust gas passage of the internal combustion engine when the electric heater of the lambda sensor is driven by the electric circuit shown in FIG. In this case, the control signal 22, the load current change 23, and the drain / source voltage 24 are shown in a graph with respect to the common signal axis 20 and time axis 21. With reference to FIG. 1, the control signal 22 is output from the TV calculator 13 to the gate connection 12.3 of the output final stage 12. The load current change 23 corresponds to a current change by the consumer 10 while the drain / source voltage 24 shows a voltage change via the field effect transistor of the output final stage 12.

  The control signal 22 is provided as an ideal rectangular wave signal. Based on the limited cut-off characteristics or delay time of the output final stage 12, the load current change 23 and the drain / source voltage 24 deviate from the ideal rectangular wave shape. Especially at low on / off ratios, such a shift will generate either a large effective voltage that drops in the consumer relative to a preset effective target voltage. The electric power converted in the consumer deviates from the target value.

  A short switch-on time with an on / off ratio in the range of 0.5% to 2% is a relatively high Set for overheat protection mode of vaporization at low temperatures. In this case, a very short on / off ratio occurs especially in the field of commercial vehicles having a high 24V battery voltage compared to a 12V passenger car battery voltage. Ceramics such as those generated when heating to a lambda sensor operating temperature of eg 800 ° C. in a subsequent heating process with a higher effective heater voltage, eg using a thermomechanical voltage that is too high, due to overheating prevention Damage is well avoided. In order to prevent the lambda sensor from becoming too hot or too cold during overheating prevention, it is very important to accurately maintain a preset effective voltage.

  Today, for lambda sensor heating, the on / off ratio is calculated from the supply voltage measured at the control unit 11 and the desired effective voltage at the heater resistance, assuming an ideal square wave change in voltage. Is done. Due to the deviation of the drain / source voltage 24 and the load current change 23 shown in FIG. 2 from the ideal rectangular wave shape, the desired effective voltage and the actually applied effective voltage are reduced with a small on / off ratio. A large temperature shift occurs, and as a result, a large temperature shift occurs.

  Thus, according to the present invention, because of the particularly small on / off ratio, the on / off ratio was actually applied to the consumer despite the deviation of the voltage change from the ideal rectangular wave shape. The effective voltage is corrected so as to correspond to the preset effective target voltage. For this purpose, the measurement during the measurement phase determines the required on / off ratio in the used output final stage 12, at which the measured effective voltage is set to the preset effective target voltage. Equivalent to. During the measurement, the voltage at the consumer is detected with an appropriate time resolution, and the effective voltage is calculated from the measured value. The on / off ratio is adapted by the control circuit until the desired effective target voltage is obtained.

  Parameters for controlling the switch characteristics of the output final stage 12, such as the cut-off characteristics and the delay time, greatly depend on the conditions under which the output final stage is operated. In this case, important operating parameters are, for example, the supply voltage and the temperature of the output final stage 12. Thus, measurements are repeated at various values of the appropriate operating parameters, such as various temperatures and supply voltages, resulting in a multidimensional characteristic map from the modified on / off ratio.

  During the subsequent application phase during operation of the consumer 10 and the output final stage 12, a corrected on / off ratio is calculated from the calculated on / off ratio and measured operating parameters using a calculation method. Is done. Therefore, during operation, voltage measurement at the consumer 10 is not necessary. The number of measured values included is based on the required adjustment accuracy of the rms value as well as the individual switch characteristics of each output final stage 12.

FIG. 3 shows the first change during the measurement phase of the calculated on / off ratio. For this purpose, the first change TV _korr T ₁ 32.1, the second change TV _korr T ₂ 32.2 and the third change TV _korr T ₃ 32.3 for the axis TV _korr 30 and the axis U _batt 31. Is shown in the graph.

FIG. 3 together with FIG. 4 shows the correction of the output final stage 12 on / off ratio in relation to the two operating parameters, namely the temperature of the output final stage 12 and the height of the supply voltage U _batt in one embodiment.

The first change TV _corr T ₁ 32.1 corresponds to an on / off ratio calculated in the same way as measured at various supply voltages U _batt for the first temperature T ₁ . The second change TV _korr T ₂ 32.2 and the third change TV _korr T ₃ 32.3 are obtained at various supply voltages U _batt for the _second temperature T ₂ and the third temperature T _3. This corresponds to the on / off ratio calculated in the same manner as.

In the first method step, for each temperature T ₁ , T ₂ , T ₃ , the respective curve change is approximated by an appropriate function related to the supply voltage U _batt . The change shown in this example approximates a mathematical function by a second order polynomial according to the first theorem.
Applied to T ₁ : TV _corr (u) = a ₁ u ² + b ₁ u + c ₁
Applies to T ₂ : TV _corr (u) = a ₂ u ² + b ₂ u + c ₂
Apply to ^{_{T 3: TV korr (u)}} = a 3 u 2 + b 3 u + c 3
In this case, for the first coefficients a, b, c: a _i = a (T _i ); b _i = b (T _i ); c _i = c (T _i ) is applied. The value of the supply voltage is indicated by u.

  FIG. 4 shows a first change in the first coefficient related to temperature. For this purpose, the fitted coefficients a (T) 42, b (T) 43 and c (T) 44 are determined relative to the coefficient axis 40 and the temperature axis 41 in relation to the temperature, as determined according to FIG. Is shown in the graph.

In the second method step, these changes in the first coefficient are approximated by a second theorem to a second mathematical function. The changes shown in the examples can also be approximated by a second order polynomial.
a (T) = s ₂ T ² + s ₁ T + S ₀
b (T) = r ₂ T ² + r ₁ T + r ₀
c (T) = q ₂ T ² + q ₁ T + q ₀
In this formula, s _i , r _i, and q _i indicate the second coefficient.
Thus, with the first function, the second function and the associated first and second coefficients, a modified on / off ratio for each allowed temperature and supply voltage can be calculated. Furthermore, in the control unit (11), both functions and only the second coefficients s ₀ , s ₁ , s ₂ , r ₀ , r ₁ , r ₂ , q ₀ , q ₁ , q ₂ need to be stored. . With these second coefficients and the second mathematical function, in the application phase, first the first coefficient is calculated as a function of the current temperature of the output final stage 12. This first factor and the first mathematical function determine a modified on / off ratio for the current supply voltage.

  The function approximating the change shown in FIGS. 3 and 4 is not limited to a polynomial or a second order polynomial. The changes in the graph are only approximated through the same form of function by fitting the respective coefficients.

  This method is not limited to the dependence of two operating parameters. As long as a corresponding function for the approximation of these changes is found, it can be used for any number of parameters.

  5, 6, 7, and 8, the method described in FIGS. 3 and 4 is extended to another operating parameter, degradation of the output final stage 12.

  To this end, FIG. 5 shows a second change in the on / off ratio calculated during the measurement phase, in relation to the supply voltage and temperature of the output final stage 12 as parameters, respectively, and FIG. 6 was calculated. FIG. 7 shows a third change in the on / off ratio, and FIG. 7 shows a fourth change in the calculated on / off ratio. In this case, the graph corresponds to the graph described in FIG.

FIG. 5 shows a change in the on / off ratio due to the _first deterioration A ₁ of the output final stage 12. For this purpose, the first change TV _korr T ₁ A ₁ 33.1, the second change TV _korr T ₂ A ₁ 33.2 and the third change TV _korr T _{3 with} respect to the axis TV _korr 30 and the axis U _batt 31. A ₁ 33.3 is shown graphically.

FIG. 6 shows a change in the on / off ratio due to the _second deterioration A ₂ of the output final stage 12. For this purpose, the first change TV _korr T ₁ A ₂ 34.1, the second change TV _korr T ₂ A ₂ 34.2 and the third change TV _korr T _{3 with} respect to the axis TV _korr 30 and the axis U _batt 31. A ₂ 34.3 is shown graphically.

FIG. 7 shows a change in the on / off ratio due to the _third deterioration A3 of the output final stage 12. For this purpose, the first change TV _korr T ₁ A ₃ 35.1, the second change TV _korr T ₂ A ₃ 35.2 and the third change TV _korr T _{3 with} respect to the axis TV _korr 30 and the axis U _batt 31. A ₃ 35.3 is shown in the graph.

The changes associated with the supply voltage U _batt shown in FIGS. 5, 6 and 7 can be approximated by a second order polynomial with the coefficients adapted accordingly. In this case, the adaptation for the respective degradations A ₁ , A ₂ , A ₃ is performed for the first temperature T ₁ , the second temperature T ₂ and the third temperature T ₃ of the output final stage 12, respectively. Is called.

  The coefficients thus determined are again provided according to the temperature of the output final stage 12 and are described by a suitable function having adapted coefficients.

  Correspondingly, FIG. 8 shows a second variation of the fitted coefficients, as determined by FIGS. 5, 6 and 7. In this case, the graph corresponds to the graph shown in FIG. 4 and is limited to a change in the coefficient a. The coefficient a is the coefficient aA1 (T) 45 for the first deterioration of the output final stage 12, the coefficient aA2 (T) 46 for the second deterioration, and the coefficient aA3 ( T) 47 is shown graphically.

  The change in the coefficient a is approximated by an appropriate other function that also has other coefficients adapted for various degradations of the output final stage 12.

  Corresponding to the variation of coefficient a shown in FIG. 8, coefficient b and coefficient c are also shown and can be approximated by a function with fitted coefficients. From these functions and coefficients, as well as previously determined functions, the on / off ratio modified in the application phase is determined taking into account the degradation and temperature of the output final stage and the height of the supply voltage.

  Depending on the method shown, any number of other operating parameters are considered.

  This method can be implemented for each effective target voltage that needs to be maintained with high accuracy. When measurements are performed at various effective target voltages, the on / off ratio for the rms values that exist between these effective target voltages can be similarly interpolated from the results.

  For the heating of the lambda sensor, the measurement is only made at the required effective target voltage to prevent heat. In the further heating process, a clearly large on / off ratio is obtained, so the determination of the on / off ratio assuming an ideal rectangular wave voltage provides sufficient accuracy.

  This method can accurately adjust the effective voltage at the consumer, in which case the effects of various operating parameters such as the output final stage 12 temperature and supply voltage can be compensated. There is no need to measure voltage during operation. Instead of measuring each output final stage 12 individually according to the manufacturing tolerance of the used output final stage 12, it is only necessary to measure, for example, only one output final stage 12 for each production batch. This method can be used for all degradations of the output final stage 12 (discrete, integrated, high potential side, low potential side). In this case, the method can be carried out both in the field of passenger cars and in the field of commercial vehicles. Only a few parameters and functions need to be executed in the control unit, which requires little memory ownership space. In this case, the function allows a quick determination of the correct on / off ratio. This is because tedious interpolation over a wide data field is unnecessary.

10 Electric Consumer 11 Control Unit 12 Output Final Stage 12.1 Drain Connection 12.2 Source Connection 12.3 Gate Connection 13 TV Calculator 14 Power Source 15 Ground 20 Signal Axis 21 Time Axis 22 Control Signal 23 Load Current Change 24 Drain / source voltage 30, 31 Axis 32.1, 33.1, 34.1 First change 32.2, 33.2, 34.2 Second change 32.3, 33.3, 34.3 Third change 40 Coefficient axis 41 Temperature axis 42, 43, 44, 45, 46, 47 Coefficient

Claims (14)

A method for output control or voltage control to supply to an electric heater of an exhaust gas sensor which is an electrical consumer (10) using an output final stage (12), wherein the output control or voltage control is adjusted In a method performed via pulse width modulation (PWM) with a possible on / off ratio,
In the measurement stage under various operating conditions described by at least two operating parameters of the output final stage (12), each measured effective voltage at the consumer is determined and the pulse width modulation is turned on / off The ratio is changed so that the measured effective voltage corresponds to the preset effective target voltage, and the on / off ratio calculated in this way is memorized in relation to the operating conditions to which it belongs, In the application phase for the condition, a modified on / off ratio is calculated from the stored on / off ratio and adjusted for output control or voltage control ;
In order to calculate a modified on / off ratio, the dependence of the calculated on / off ratio on the first operating parameter for various values of the second operating parameter is determined by a first mathematical expression. At least approximately by the first theorem of the first function and the associated first coefficient, and the dependence of the first coefficient on the second operating parameter is expressed by the second mathematical function and At least approximately describing the second theorem of the second coefficient to which it belongs, storing the second coefficient and the mathematical function, and storing the stored second coefficient and the second mathematical function In an application step for the current second operating parameter, determining a first coefficient belonging to the current second operating parameter, and by means of the first coefficient and the first mathematical function , The current first driving parameter Methods for characterized, outputs control or voltage control calculating a corrected on / off ratio for the chromatography data.   In order to calculate a modified on / off ratio, the dependence of the calculated on / off ratio on the various operating parameters is at least approximated by a fitted mathematical function with adapted coefficients. Describe the function and the associated coefficient, and determine a modified on / off ratio with the memorized function and the memorized coefficient in the application phase for the current operating parameter The method of claim 1, wherein: 3. Method according to claim 1 or 2 , characterized in that, for each other operating parameter, other theorems of other functions and other coefficients of the affiliation are determined. The dependence of the coefficients determined for the operating parameters considered in advance for the various values of the other operating parameters is at least approximated by other mathematical functions and other theorems of the other coefficients belonging To store other coefficients and other mathematical functions, and to determine the coefficients determined for the operating parameters considered in advance in the application phase for the actual values of the other operating parameters It characterized a method according to any one of claims 1 to 3.   A method for output control or voltage control to supply to an electric heater of an exhaust gas sensor which is an electrical consumer (10) using an output final stage (12), wherein the output control or voltage control is adjusted In a method performed via pulse width modulation (PWM) with a possible on / off ratio,
  In the measurement stage under various operating conditions described by at least two operating parameters of the output final stage (12), each measured effective voltage at the consumer is determined and the pulse width modulation is turned on / off The ratio is changed so that the measured effective voltage corresponds to the preset effective target voltage, and the on / off ratio calculated in this way is memorized in relation to the operating conditions to which it belongs, In the application phase for the condition, a modified on / off ratio is calculated from the stored on / off ratio and adjusted for output control or voltage control;
  The dependence of the coefficients determined for the operating parameters considered in advance for the various values of the other operating parameters is at least approximated by other mathematical functions and other theorems of the other coefficients belonging To store other coefficients and other mathematical functions, and to determine the coefficients determined for the operating parameters considered in advance in the application phase for the actual values of the other operating parameters A method for power control or voltage control.   The measuring step comprises digitally detecting a voltage change in the consumer (10) and determining a measured effective voltage in the consumer (10) from the voltage change. 6. The method according to any one of 5 above. The modification of the on / off ratio, which comprises carrying out Oite to less than 5% on / off ratio, The method according to any one of claims 1 to 6.   8. The method according to claim 1, wherein the on / off ratio correction is performed at an on / off ratio of less than 2%.
The deterioration of at least the value of the temperature and / or the supply voltage of the output final stage and / or the output final stage (12), characterized in that considered as the operating parameter, to any one of claims 1 8 The method described. A quadratic polynomial is used as a function to describe the dependency of the calculated on / off ratio on the operating parameter and / or to describe the dependency of the coefficient on the operating parameter 10. The method according to any one of claims 1 to 9 , characterized in that: For various effective target voltage, and determines the coefficients and / or function, respectively, the method according to any one of claims 1 10. An apparatus for output control or voltage control to supply to an electric heater of an exhaust gas sensor which is an electrical consumer (10) using an output final stage (12), wherein the output control or voltage control is adjusted In a type in which a control unit (11) is provided in the output final stage (12), which is performed via pulse width modulation (PWM) having a possible on / off ratio,
The control unit (11) has a memory for storing a function for describing the dependency of the modified on / off ratio on the operating parameter of the output final stage (12) and a coefficient to which it belongs. and, wherein the control unit is stored using the coefficients and functions for computing corrected on / off ratio for the actual value of the operating parameter, has at least one program sequence ,
The control unit (11) determines the dependence of the on / off ratio on the first operating parameter for various values of the second operating parameter, the first mathematical function and the first of the belonging. And the dependence of the first coefficient on the second operating parameter is expressed as a second mathematical function and a second Storing in the memory the second coefficient and the mathematical function used to at least approximately describe the second theorem of the coefficient;
The control unit (11) has a second coefficient stored in the memory and a second mathematical function, and in the application phase for the current second operating parameter, the current second driving parameter to determine a first coefficient belongs, by the first coefficient and the first mathematical function, you calculate the corrected oN / oFF ratio for the first operating parameters of the presently A device for output control or voltage control.   An apparatus for output control or voltage control to supply to an electric heater of an exhaust gas sensor which is an electrical consumer (10) using an output final stage (12), wherein the output control or voltage control is adjusted In a type in which a control unit (11) is provided in the output final stage (12), which is performed via pulse width modulation (PWM) having a possible on / off ratio,
  The control unit (11) has a memory for storing a function for describing the dependency of the modified on / off ratio on the operating parameter of the output final stage (12) and a coefficient to which it belongs. The control unit has at least one program sequence for calculating a modified on / off ratio for the actual value of the operating parameter using the stored coefficients and functions ,
  The control unit (11) determines the dependence of the coefficients determined for the operating parameters considered in advance for various values of the other operating parameters, other mathematical functions, and other coefficients belonging. Other coefficients and other mathematical functions used to at least approximately describe the other theorems of are stored in the memory and taken into account in the application phase for the actual values of other operating parameters. A device for power control or voltage control, characterized in that a coefficient determined for said operating parameter is determined. Output control or voltage control of an electric heater (14) of an exhaust gas sensor in an exhaust gas passage of an internal combustion engine in the method according to any one of claims 1 to 11 and the use of the device according to claim 12 or 13. Use of a method and apparatus for power control or voltage control, characterized in that it is used for

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