Method for correcting an angle error during sensorless detection of a rotation angle of a rotor of an electric machine by means of injection methods

Abstract

The invention discloses a method for correcting an angle error during sensorless detection of a rotation angle of a rotor of an electric machine by means of injection methods, comprising: processing a present Q current lq by means of a first filter element and a present D current Id by means of a second filter element; determining a magnitude of the processed D current Id_hp and determining a moving average of the magnitude; determining a square of the moving average; calculating a product of the processed Q current ld_hp and the processed D current ld_hp and determining a moving average of the product; and calculating a quotient of the square and the moving average of the product, and providing the quotient as angle error data. The invention further discloses a computing unit for carrying out the method and a vehicle having an electric machine and the computing unit.

Description

[0001] Description

[0002] Method for correcting an angular error in sensorless detection of a rotation angle of an electric machine rotor using an injection method

[0003] The present invention relates to a method for correcting an angular error in sensorless detection of the rotation angle of a rotor of an electric machine by means of an injection method. The invention further relates to a computing unit for carrying out the method and a vehicle comprising an electric machine and the computing unit.

[0004] Methods for sensorless angle detection of an electric machine rotor using injection techniques are known. In this process, a

[0005] The current amplitude of an estimated Q-axis, generated by voltage injection into an estimated D-axis, is evaluated. Subsequently, an angular error is determined, and the estimated angle is corrected by this error.

[0006] Based on this, the object of the present invention is to provide an advanced technique for correcting an angular error when using an injection method. In particular, dependencies of the angular error are to be minimized and / or compensated in order to improve the estimation of a rotation angle.

[0007] This problem is solved by the features of the independent claims. Advantageous embodiments are the subject of the dependent claims.

[0008] A method for correcting an angular error in sensorless detection of the rotation angle of an electric machine rotor using an injection method has been disclosed. The method comprises the following steps: processing a current Q-current l q using a first filter element and a current D-stream Id using a second filter element; determining an amount of the processed D-stream ld_h P and determining a moving average of the magnitude; determining a squaring of the moving average; calculating a product of the processed Q-stream l q _h P and the processed D-current ld_h P and determining a moving average of the product; and calculating a quotient of the squaring and the moving average of the product, and providing the quotient as angular error data.

[0009] The injection method can, for example, be configured to superimpose an electrical signal (voltage signal) onto a voltage used to drive the electric machine. The voltage can also be a control signal for the electric machine. The electrical signal can then be injected, for example, into the estimated D-axis of the control signal.

[0010] The control signal can, for example, be a modulated control signal, particularly one that exhibits pulse-width modulation (PWM). The frequency of the electrical signal can depend on the frequency of the control signal. Specifically, the frequency of the electrical signal can be determined according to the Nyquist-Shannon sampling theorem or the Whittaker-Kotelnikov-Shannon sampling theorem.

[0011] The filter element can, for example, include a high-pass filter designed to cut off or attenuate frequencies below a cutoff frequency. Furthermore, the filter element can also include a band-pass filter designed to cut off or attenuate frequencies below a lower cutoff frequency and above an upper cutoff frequency.

[0012] The angular error data can, for example, include information about an angular error between an estimated Q-axis and an actual Q-axis.

[0013] The current amplitude in the Q-axis can be proportional to an angular error that depends on operating points and various parameters of the electric machine. Furthermore, the angular error can also depend on parameters of the injection method.

[0014] The disclosed method can thus be used to determine and account for the angular error in the control of an electric machine. Furthermore, parameters affecting the current amplitude can be kept constant using this method. In particular, the dependence between the amplitude of the voltage injection in the D-axis and / or the frequency of the injection voltage can be reduced.

[0015] The procedure may further include calculating a product from the quotient and compensation data, and providing the product as angular error data.

[0016] The compensation data can, for example, have values ​​designed to compensate for and / or eliminate dependencies on inductances of the electrical machine.

[0017] Accordingly, the angular error can be evaluated independently of the operating points of the electrical machine, so that the angular error is, for example, independent of a change in the differential inductance.

[0018] The compensation data can include at least one value Lkomp, which is based on a calculation from provided differential inductance values ​​of the D current Ldd and differential inductance values ​​of the Q current L qq based.

[0019] The method can particularly preferably linearize a detected angular error, for example an angular error signal, or angular error data, relative to an actual angular error of the electrical machine. This can be especially relevant at operating points where the electrical machine does not behave linearly due to iron saturation effects. This can occur particularly at high Q-currents, since the differential inductances (Ldd and L) then become significantly higher.qq ) change the most.

[0020] Accordingly, the compensation data can be designed to account for dependencies on the differential inductance in the Q-axis L. qq and / or to compensate for and / or eliminate the differential inductance in the D-axis Ldd.

[0021] The calculation can be based on the following formula: ^komp Lqq / (Ldd Lq .

[0022] The compensation data can include lookup table values, which provide compensation values ​​and / or scaling values ​​for the provided differential inductance values ​​of the D-current Ldd and / or for the differential inductance values ​​of the Q-current L. qq exhibit

[0023] Using lookup table values ​​allows for better parameter compensation and simplifies calculations. Therefore, faster processing of the procedure is possible with lookup table values ​​compared to procedures without them.

[0024] The procedure can also include determining angle data from the angle error data.

[0025] The angular data can be configured, for example, to be processed by an aß filter and / or directly supplied to a tracking controller. The processed angular data can preferably include an angular velocity and / or a rotation angle.

[0026] Also disclosed is a computing unit that is configured and programmed to execute the disclosed method. The computing unit can be, for example, a microcomputer, a computer system, a networked computer system, and / or a cloud-based computer system. The computing unit is configured to acquire and process current values ​​from the electrical machine used to execute the method.

[0027] Also disclosed is a vehicle with an electric machine and the disclosed computing unit.

[0028] The present invention is described in detail below with reference to the figures. Figure 1 shows a circuit arrangement with an angle estimator and a modulation module;

[0029] Fig. 2 shows a setup of the angle estimator from Fig. 1;

[0030] Fig. 3 shows another circuit arrangement with an angle estimator and a modulation module;

[0031] Fig. 4 shows a setup of the angle estimator from Fig. 3; and

[0032] Fig. 5 is a diagram showing the course of a ratio of L q Ld represents an angular error.

[0033] The present disclosure is described below with reference to preferred embodiments and the figures. However, this description of the disclosure should not be considered exhaustive.

[0034] Fig. 1 shows a circuit arrangement 1 with an angle estimator 20 for correcting an angular error in a sensorless detection of a rotation angle of a rotor of an electric machine by means of an injection method and a modulation module 18 for generating an offset voltage value Uaß.

[0035] A transformation module 10 processes a current value laß and an estimated angle value to determine a current value Idq, which is then provided to the angle estimator 20. The current value laß is based on measured current values ​​of the electric machine. The transformation module 10 can determine the current value Idq, in particular, using a d / q transformation (also called a Park transformation).

[0036] The angle estimator 20 processes the current value Idq to determine angle error data, which is provided to a filter module 14.

[0037] Filter module 14 determines an angular velocity value and a filtered angle value, which are output and provided to angle module 16 and modulation module 18. Filter module 14 can determine the angular velocity value and the filtered angle value, in particular, using an aß filter.

[0038] Angle module 16 processes the angular velocity value and the filtered angle value to determine the estimated angle value, which is then provided to transformation module 10. Angle module 16 can be specifically configured to compensate for delays, latencies, or processing times within the system.

[0039] Modulation module 18 processes the angular velocity value and the filtered angle value to determine the offset voltage value Uaß, which is designed to correct the angular error. The offset voltage value Uaß can be supplied to the electrical machine, e.g., to an electrical machine controller.

[0040] Fig. 2 shows a setup of the angle estimator 20 from Fig. 1, wherein the current value Idq is divided into a current D-current Id and a current Q-current l qThe current D-stream Id is split. A first filter element 21 transforms it into a processed D-stream ld_h. P processed. The current Q-stream l q is processed by a second filter element 22 into a Q-stream l q _h P processed.

[0041] The first filter element 21 and the second filter element 22 are configured as high-pass filters. Both filter elements 21 and 22 can also each be configured as band-pass filters.

[0042] The processed D-current ld_h P is provided to a first determination element 23.1 and a first calculation module 24.1. The first determination element 23.1 determines an amount of the processed D-stream ld_h. P The first calculation module, 24.1, calculates a product of the processed Q-stream l q _h P and the processed D-current ld_h P. A second determining element 23.2 determines a moving average of the absolute value and a third determining element 23.3 determines a squared value of the moving average.

[0043] A fourth determining element 23.4 calculates a moving average of the product. A second calculation element 24.2 calculates a quotient of the squared value and the moving average of the product. Furthermore, the second calculation element 24.2 provides the quotient as angular error data.

[0044] Fig. 3 shows a preferred circuit arrangement 1 with an angle estimator 20 for correcting an angular error in a sensorless detection of a rotation angle of a rotor of an electric machine, a compensation module 12 and a modulation module 18 for generating an offset voltage value Uaß.

[0045] A transformation module 10 processes a current value laß and an estimated angle value to determine a current value Idq, which is then provided to the angle estimator 20. The current value laß is based on measured current values ​​of the electric machine. The transformation module 10 can determine the current value Idq, in particular, using a d / q transformation (also called a Park transformation).

[0046] The compensation module 12 processes the current value Idq to calculate a differential inductance value of the D current Ldd and a differential inductance value of the Q current L qq to determine these inductance values ​​Ldd, L qq are then provided to the angle estimator 20. The compensation module 12 can adjust the differential inductance value of the D-current Ldd and / or the differential inductance value of the Q-current L. qq Preferably determined using lookup table values.

[0047] The angle estimator 20 processes the current value Idq to determine angle error data, which is provided to a filter module 14.

[0048] Filter module 14 determines an angular velocity value and a filtered angle value, which are output and provided to angle module 16 and modulation module 18. Filter module 14 can determine the angular velocity value and the filtered angle value, in particular, using an aß filter.

[0049] Angle module 16 processes the angular velocity value and the filtered angle value to determine the estimated angle value, which is then provided to transformation module 10. Angle module 16 can be specifically configured to compensate for delays, latencies, or processing times within the system.

[0050] Modulation module 18 processes the angular velocity value and the filtered angle value to determine the offset voltage value Uaß, which is designed to correct the angular error. The offset voltage value Uaß can be supplied to the electrical machine, e.g., to an electrical machine controller.

[0051] Fig. 4 shows a setup of an angle estimator 20 from Fig. 1, wherein the current value Idq is divided into a current D-current Id and a current Q-current l q The current D-stream Id is split. A first filter element 21 transforms it into a processed D-stream ld_h. P processed. The current Q-stream l q is processed by a second filter element 22 into a Q-stream l q _h P processed.

[0052] The first filter element 21 and the second filter element 22 are configured as high-pass filters. Both filter elements 21 and 22 can also each be configured as band-pass filters.

[0053] The processed D-current ld_h P is provided to a first determination element 23.1 and a first calculation module 24.1. The first determination element 23.1 determines an amount of the processed D-stream ld_h. P The first calculation module, 24.1, calculates a product of the processed Q-stream l q _h P and the processed D-current ld_h P . A second determining element 23.2 determines a moving average of the absolute value and a third determining element 23.3 determines a squared value of the moving average.

[0054] A fourth determining element 23.4 determines a moving average of the product. A second calculation element 24.2 calculates a quotient of the squared value and the moving average of the product.

[0055] A fifth determining element 23.5 determines a compensation value with the differential inductance value of the D current Ldd and the differential inductance value of the Q current L qq A third calculation element, 24.3, calculates a product of the quotient and the compensation value and provides the product as angular error data.

[0056] Fig. 5 shows a diagram illustrating a ratio of L q to Ld over an angular error. The diagram includes a first graph 31, which shows the ratio of L qThe second graph 32 represents a compensation value and / or scaling value relative to the first graph 31, which is based on a calculation of Lqq / Ldd — Lqq~).

[0057] The second graph 32 can represent a preferred application area for the method for compensating angular errors in the range of 0 to 40°.

[0058] Reference symbol list

[0059] 1 Circuit arrangement

[0060] 10 Transformation Module

[0061] 12 Compensation Module

[0062] 14 Filter module

[0063] 16 Angle Module

[0064] 18 Modulation Module

[0065] 20 angle estimators

[0066] 21 first filter element

[0067] 22 second filter element

[0068] 23.1 first determining element

[0069] 23.2. second determining element

[0070] 23.3 third determining element

[0071] 23.4 fourth determining element

[0072] 23.5 fifth determining element

[0073] 24.1 first calculation element

[0074] 24.2 second calculation element

[0075] 24.3 third calculation element

[0076] 31 first graph

[0077] 32 second graph

Claims

Claims 1. Method for correcting an angular error in sensorless detection of a rotation angle of a rotor of an electric machine by means of an injection method, comprising: Processing a current Q-stream l q by means of a first filter element and a current D-stream Id, and by means of a second filter element, determining an amount of the processed D-stream ld_h P and determining a moving average of the amount; Determining the squaring of the moving average; Calculating a product from the processed Q-stream l q _h P and the processed D-current ld_h P and determining a moving average of the product; and calculating a quotient of the squaring and the moving average of the product, and providing the quotient as angular error data.

2. Method according to claim 1, characterized in that the method further comprises calculating a product from the quotient and compensation data and providing the product as angular error data.

3. Method according to claim 2, characterized in that the compensation data comprises at least one value Lkomp, which is based on a calculation of provided differential inductance values ​​of the D-current Ldd and differential inductance values ​​of the Q-current L qq based.

4. Method according to claim 3, characterized in that the calculation is based on the following formula: komp Lqq / Ldd Lqq).

5. Method according to claim 3 or 4, characterized in that the compensation data comprises lookup table values ​​which provide compensation values ​​and / or scaling values ​​for the provided differential inductance values ​​of the D current (Ldd) and / or the provided differential inductance values ​​of the Q current (L qq exhibit.

6. Method according to one of claims 1 to 5, characterized in that the method further comprises determining angle values ​​from the angle error data.

7. Computing unit that is trained and programmed to execute the method according to any one of claims 1 to 6.

8. Vehicle with an electric machine and the computing unit according to claim 7.

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