Method for correcting direction of rotation, control unit and electric motor

Abstract

The invention relates to a method (10) for correcting the direction of rotation of a rotational movement (16) in an electric motor (12) having a stator (14) and a rotor (18) which performs the rotational movement (16) relative to the stator, comprising the following steps: in a first calculation step (28), calculating (24) a first specified rotational angle (26), the first specified rotation angle sets a rotor rotation angle (30) of the rotor (18) relative to the stator (14), which rotor rotation angle can be changed by a rotational movement (16) of the rotor (18); calculating (34) a first input angle of rotation (36) as a function of the first specified angle of rotation (26); in a second calculation step (42), a second specified angle of rotation (40) is calculated (38) as a function of the first input angle of rotation (36), and if a rotational direction error (46) to the rotational movement (16) of the rotor (18) is detected (44), the second specified angle of rotation (40) is calculated (38). If so, the second specified rotation angle (40) and at least one further calculation variable (50) calculated from the second specified rotation angle (40) are each angularly corrected (48) by 180 DEG. The invention also relates to a control unit (74) and an electric motor (12).

Description

Technical Field

[0001] This invention relates to the method according to claim 1. The invention also relates to a control unit and an electric motor. Background Technology

[0002] WO 2020 001 681A1 describes a torque transmission device including an electric motor and a control unit. The electric motor has a stator and a rotor that can rotate relative to the stator by rotational motion. The control unit can output current pulses to the electric motor, wherein the current pulses cause the rotor to rotate in a first rotation direction and at a first rotation angle, thereby generating an induced voltage, which is received by the control unit. The control unit determines the rotation direction and / or the rotation angle of the rotor relative to the stator by means of the induced voltage. Summary of the Invention

[0003] The purpose of this invention is to execute the rotational motion of the rotor in a more controllable and accurate manner.

[0004] At least one of these objectives is achieved by a method having the features of claim 1. This allows for more accurate and reliable calculation of a specified rotation angle, enabling the rotor to perform the desired rotational motion in a more precise and controllable manner. Vibration occurring during the operation of the electric motor can be reduced.

[0005] An electric motor can be installed in the vehicle's drivetrain. The drivetrain can be a hybrid drivetrain. The electric motor can provide driving power to propel the vehicle. The vehicle can be a motor vehicle. An electric motor can drive a fluid pump. The electric motor can be a pump motor. The fluid pump can be a hydraulic pump.

[0006] An electric motor can be operated without an encoder. This method can be performed during encoder-free operation of the electric motor. The electric motor can be operated specifically in an encoder-free manner. Encoder-free operation is understood to mean operating without considering the rotor rotation angle measured by sensors, such as position sensors.

[0007] An electric motor can be controlled via at least three motor phases. The electric motor can be a brushless DC motor. The electric motor can also be a permanent magnet synchronous motor.

[0008] This method can be executed when the rotor starts to rotate, that is, at a point in time when the rotor has not yet reached the required rotor speed.

[0009] Rotation direction error can be the deviation between the rotor's expected rotation direction and its current rotation direction.

[0010] The first specified rotation angle sets the rotor rotation angle at a first time point. The second specified rotation angle sets the rotor rotation angle at a subsequent second time point. Each specified rotation angle can specify an electrical operating variable used for the rotor's rotational motion. The electrical operating variable can be the phase voltage on at least one motor phase.

[0011] In a preferred embodiment of the invention, it is advantageous if the calculation variable is a second input rotation angle calculated based on a second specified rotation angle. Therefore, angle correction can be performed on both the second specified rotation angle as the output of the angle calculation in the second calculation step and the second input rotation angle as the input of the subsequent angle calculation in a subsequent calculation step, and thus the calculation of the subsequent specified rotation angle can be performed more accurately based on the second input rotation angle.

[0012] In an advantageous embodiment of the invention, a second input rotation angle is calculated in the second calculation step. This second input rotation angle can be output together with a second specified rotation angle and used as input for calculating another specified rotation angle in a subsequent calculation step.

[0013] In a specific embodiment of the invention, it is advantageous to calculate a third specified rotation angle in a third calculation step after the second calculation step, based on the second input rotation angle corrected by angle correction. The 180° offset corrected by angle correction can be retained in the specified rotation angle of subsequent calculation steps.

[0014] In a preferred embodiment of the invention, it is advantageous to calculate the first input rotation angle in the first calculation step. In the first calculation step, the first input rotation angle can be calculated simultaneously with a first specified rotation angle, or calculated with a time delay.

[0015] In a preferred embodiment of the invention, a first input rotation angle is stored for retrieval in subsequent calculation steps. The first input rotation angle can be stored in a memory for retrieval.

[0016] In a preferred embodiment of the invention, the calculated variable is an input signal used to generate an injection signal applied to the electric motor to determine the rotor rotation angle. The injection signal may include a high-frequency injection voltage in a motor phase to identify the rotor rotation angle. The injection signal can be generated at rotor rotation speeds below the limit speed. If the rotor rotation speed is equal to or higher than the limit speed, an injection signal may not be present.

[0017] The calculation variables may include the second input rotation angle and the input signal. In the angle correction step, both the second input rotation angle and the angle of the input signal can be corrected by 180°.

[0018] In a specific embodiment of the invention, it is advantageous if the detection of the rotation direction error occurs before, during, or after the calculation of the second specified rotation angle. The rotation direction error can be detected before, during, or after the calculation of the first specified rotation angle.

[0019] Furthermore, within the context of this invention, a control unit having the features of claim 9 is proposed to address at least one of the aforementioned problems. The control unit can be disposed in a vehicle.

[0020] Furthermore, within the context of this invention, an electric motor having the features of claim 10 is proposed to address at least one of the aforementioned problems. This allows the electric motor to operate more reliably. It improves the durability of the electric motor. Additionally, the electric motor results in less intrusive noise.

[0021] Other advantages and advantageous embodiments of the invention will become clear from the description of the figures and accompanying drawings. Attached Figure Description

[0022] The invention will now be described in detail with reference to the accompanying drawings. Specifically, in the drawings:

[0023] Figure 1 The illustration shows a method for correcting rotational speed according to a specific embodiment of the present invention.

[0024] Figure 2 The diagram shows a timing diagram of the execution of a method for correcting the rotation direction according to another embodiment of the present invention.

[0025] Figure 3 The diagram illustrates a control unit in a specific embodiment of the present invention. Detailed Implementation

[0026] Figure 1 An electric motor and a method for correcting the direction of rotation are illustrated in a specific embodiment of the present invention. The method 10 for correcting the direction of rotation is performed in an electric motor 12, which has a stator 14 and a rotor 18 that performs a rotational motion 16 relative to the stator. If the rotor 18 performs the rotational motion 16 along a first rotational direction 20 and therefore against a desired second rotational direction 22, the rotational direction correction will correct the rotational direction such that the rotational motion 16 has the desired second rotational direction 22.

[0027] Method 10 includes calculating a first specified rotation angle 26 in a first calculation step 28. The rotor rotation angle 30 of the rotor 18 relative to the stator 14 is set at a first time point 32 according to the first specified rotation angle 26, which can be varied by the rotational movement 16 of the rotor 18.

[0028] Method 10 further includes calculating 34 a first input rotation angle 36 based on a first specified rotation angle 26. The calculation 34 of the first input rotation angle 36 is preferably performed in the first calculation step 28. The first input rotation angle 36 is stored in memory 37 for retrieval in subsequent calculation steps.

[0029] Subsequently, in the second calculation step 42, the second specified rotation angle 40 is calculated based on the first input rotation angle 36. The first specified rotation angle 26 sets the rotor rotation angle 30 at the first time point 32. The second specified rotation angle 40 sets the rotor rotation angle 30 at the subsequent second time point 43.

[0030] If a rotational direction error 46 is detected in the rotational motion 16 of rotor 18 from 44, then the second specified rotation angle 40 and at least one additional calculated variable 50 calculated from the second specified rotation angle 40 are each angularly corrected by 180° 48. The detection 44 of the rotational direction error 46 occurs before, during, or after the calculation 38 of the second specified rotation angle 40.

[0031] The calculation variable 50 is, for example, a second input rotation angle 52 calculated from a second specified rotation angle 40. The second input rotation angle 52 is preferably calculated in the second calculation step 42 by calculation 53, and is used to calculate the third specified rotation angle 55 in a subsequent third calculation step 56. Therefore, for all specified rotation angles following the second specified rotation angle 40, the angle correction 48 permanently maintains a 180° offset, particularly until another angle correction 48 is performed.

[0032] The calculation variable 50 can also be an input signal 57 used to generate an injection signal 58, which is applied to the electric motor 12 to determine the rotor rotation angle 30.

[0033] Figure 2 A timing diagram illustrating the execution of a method for correcting rotation direction according to another specific embodiment of the present invention is shown. Figure 2 Figure a) illustrates the timing of the trigger signal 59 that triggers the angle correction 48. At time point t1, the trigger signal 59 changes from 0 to 1, thereby initiating the angle correction 48. The 180° offset performed by the angle correction 48 is then maintained in place over time.

[0034] exist Figure 2 In b), the phase voltages are shown in the stator fixed reference frame, here the αβ-coordinate system. The rotor begins to perform rotational motion 16 only at time point t0. A high-frequency injection signal 58 present at the first phase voltage 62 is used to determine the rotor rotation angle when the rotational motion 16 begins from the stationary state. The second phase voltage 64 also has an injection signal 58 when the rotational motion 16 occurs.

[0035] exist Figure 2 In c), a rotor speed 66, measured here for reference using a position sensor, is shown in comparison with the rotor speed 68 calculated in particular by the injected signal 58.

[0036] exist Figure 2 In section d), the rotor rotation angle 70, measured here using a position sensor for reference, is shown compared to the specified rotation angle 72. It can be seen that the hypothetical specified rotation angle 72 is offset by 180°, which is adjusted at time point t1 to the currently measured rotor rotation angle 70 using angle correction 48. By simultaneously changing the specified rotation angle 72—here a second specified rotation angle 40 as the specified rotation angle 72 at time point t1—and the second input rotation angle, the specified rotation angle 72 can better follow the measured rotor rotation angle 70, and damped vibration at the specified rotation angle 72 can be reduced or prevented.

[0037] After the angle correction 48 has been performed, the rotational motion 16 of the rotor changes in the opposite direction of rotation, which can be seen here by the change in the reference sign of the measured rotor speed 66.

[0038] Figure 3 A control unit according to a specific embodiment of the present invention is shown. The control unit 74 has a computing device 76 for executing a method for correcting the rotation direction, such as... Figure 1 As described in [the text].

[0039] List of reference numerals

[0040] 10 methods

[0041] 12 Electric motors

[0042] 14 Stator

[0043] 16 Rotational motion

[0044] 18 rotors

[0045] 20 First rotation direction

[0046] 22 Second Rotation Direction

[0047] 24 Calculation

[0048] 26 First specified rotation angle

[0049] 28 First Calculation Step

[0050] 30° Rotor rotation angle

[0051] 32 First Time Point

[0052] 34 Calculation

[0053] 36 First input rotation angle

[0054] 37. Memory

[0055] 38 Calculation

[0056] 40 Second specified rotation angle

[0057] 42 Second Calculation Step

[0058] 43 Second Time Point

[0059] 44 Detection

[0060] 46. ​​Rotation direction error

[0061] 48 angle correction

[0062] 50 Calculate variables

[0063] 52 Second input rotation angle

[0064] 54 Calculation

[0065] 55 Third specified rotation angle

[0066] 56 Third Calculation Step

[0067] 57 Input Signal

[0068] 58 Injection Signal

[0069] 59 Trigger Signal

[0070] 62 First phase voltage

[0071] 64 Second phase voltage

[0072] 66. Measured rotor speed

[0073] 68. Calculated rotor speed

[0074] 70 Measured rotor rotation angle

[0075] 72 Specified rotation angle

[0076] 74 Control Unit

[0077] 76 Computing devices

Claims

1. A method (10) for correcting the rotational direction of a rotational motion (16) in an electric motor (12), the electric motor having a stator (14) and a rotor (18) performing the rotational motion (16) relative to the stator, the method comprising the following steps: In the first calculation step (28), a first specified rotation angle (26) is calculated (24). The first specified rotation angle sets the rotor rotation angle (30) of the rotor (18) relative to the stator (14). The rotor rotation angle can be changed by the rotational movement (16) of the rotor (18). The first input rotation angle (36) is calculated (34) based on the first specified rotation angle (26). In the second calculation step (42), the second specified rotation angle (40) is calculated (38) based on the first input rotation angle (36), and If a rotational direction error (46) is detected (44) in the rotational motion (16) of the rotor (18), then the second specified rotation angle (40) and at least one additional calculated variable (50) calculated from the second specified rotation angle (40) are respectively angularly corrected (48) by 180°.

2. The method (10) according to claim 1, characterized in that, The calculation variable (50) is the second input rotation angle (52) calculated from the second specified rotation angle (40).

3. The method (10) according to claim 2, characterized in that, In the second calculation step (42), the second input rotation angle (52) is calculated.

4. The method (10) according to claim 2 or 3, characterized in that, After the second calculation step (42), in the third calculation step (56), the third specified rotation angle (55) is calculated (55) based on the second input rotation angle (52) corrected by the angle correction (48).

5. The method (10) according to any one of the preceding claims, characterized in that, The first input rotation angle (36) is calculated in the first calculation step (28).

6. The method (10) according to any one of the preceding claims, characterized in that, Store the first input rotation angle (36) for retrieval in subsequent calculation steps.

7. The method (10) according to any one of the preceding claims, characterized in that, The calculated variable (50) is an input signal (57) used to generate an injection signal (58), which is applied to the electric motor (12) to determine the rotor rotation angle (30).

8. The method (10) according to any one of the preceding claims, characterized in that, The detection (44) of the rotation direction error (46) occurs before, during, or after the calculation of the second specified rotation angle (40).

9. A control unit (74) having a computing device (76) for performing the method (10) according to any one of the preceding claims.

10. An electric motor (12) having a stator (14) and a rotor (18) rotatable relative to the stator, the rotational motion (16) of the rotor being adjustable by the method (10) according to any one of claims 1 to 8.

Images