Motor device and vehicle
Through software calculations and fault safety control in the inverter control unit, the problem of abnormal detection of the rotary transformer when the vehicle is bumpy was solved, and the offset detection of the rotation angle sensor and the stability of motor control were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NIDEC ELESYS CORP
- Filing Date
- 2021-04-07
- Publication Date
- 2026-07-14
AI Technical Summary
In the prior art, rotary transformers are prone to malfunction when the vehicle is traveling on bumpy roads, which makes it impossible to accurately detect the rotation angle and thus affects the motor control.
The inverter control unit performs software calculations, and the installation position offset angle of the rotation angle sensor is calculated by detecting the voltage phase difference of the motor unit. Combined with fault safety control, calculations are avoided when they are not necessary.
This technology enables the detection of physical offset of the rotation angle sensor at the software level without the need for additional devices, improving the accuracy of motor control and preventing motor acceleration and component failure caused by offset.
Smart Images
Figure CN115189613B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an electric motor device, and more particularly to an electric motor device including a rotation angle sensor for detecting the rotation angle of the electric motor. Background Technology
[0002] Previously, a rotary transformer was typically used to detect the rotation angle of motors used in vehicles. However, external factors such as the bumpy driving of vehicles equipped with motors can sometimes cause the rotary transformer to malfunction. When the rotary transformer malfunctions, the rotation angle cannot be accurately detected, thus hindering accurate motor control.
[0003] As a method for diagnosing abnormalities in a rotary transformer, for example, Japanese Patent No. 4475642, which is patent document 1, discloses that the difference between the sum of multiple sampled values output from the rotary transformer within one cycle and the zero value is set as an offset value, and when the offset value exceeds a threshold, it is determined that the rotary transformer has malfunctioned.
[0004] Furthermore, Japanese Patent Application Publication No. 2020-114057, which is patent document 2, discloses that: a first electrical angle and a second electrical angle are calculated based on the signal output from the rotary transformer, and when the first electrical angle and the second electrical angle are inconsistent, it is determined that the rotary transformer is malfunctioning.
[0005] Existing technical documents
[0006] Patent Document 1: Japanese Patent No. 4475642
[0007] Patent Document 2: Japanese Patent Application Publication No. 2020-114057 Summary of the Invention
[0008] However, existing technologies can only detect anomalies such as output offset of the resolver, but cannot detect physical offset (angular offset) of the resolver.
[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a motor device that can easily detect the physical offset of the rotation angle sensor in a software manner without additional external devices.
[0010] In a first embodiment of the electric motor device of the present invention, the device includes: an electric motor section having a rotor and a stator; an inverter section for converting an input voltage into a three-phase AC voltage and providing it to the electric motor section; an inverter control section for controlling the inverter section; and a rotation angle sensor fixed to the electric motor section for detecting the rotation angle of the electric motor section. The inverter control section includes a calculation section for calculating the offset angle of the mounting position of the rotation angle sensor based on the difference between the measured value and the theoretical value of the voltage phase of the electric motor section.
[0011] The electric motor device according to the present invention can easily detect the physical offset of the rotation angle sensor in a software manner without additional external devices.
[0012] In a second embodiment of the electric motor device of the present invention, in the first embodiment, the inverter control unit further includes a determination unit that determines whether the calculation unit is allowed to perform calculations. If the determination unit allows the calculation unit to perform calculations, the calculation unit calculates the offset angle of the mounting position of the rotation angle sensor.
[0013] According to the electric motor device of the present invention, the calculation unit of the inverter control unit can perform the calculation only when it is necessary to calculate the offset angle of the mounting position of the rotation angle sensor. Therefore, the operation of the calculation unit can be made more efficient, and the calculation of the offset angle of the mounting position of the rotation angle sensor can be avoided when it is not necessary.
[0014] In a third embodiment of the electric motor device of the present invention, in the second embodiment, the determination unit determines whether the calculation unit is allowed to perform calculations based on the current flowing through the electric motor, the system state, and the rotational speed of the electric motor.
[0015] According to the electric motor device of the present invention, the calculation unit is only allowed to calculate the offset angle of the mounting position of the rotation angle sensor when all three conditions are met: the current flowing through the electric motor, the system state, and the rotational speed of the electric motor. Therefore, the operation of the calculation unit can be made more efficient, and the calculation of the offset angle of the mounting position of the rotation angle sensor is avoided when it is not necessary.
[0016] In a fourth embodiment of the electric motor device of the present invention, in the first embodiment, the electric motor device is preferably mounted on a vehicle, the vehicle having a vehicle control unit, the inverter control unit further including a diagnostic unit and a control unit, the diagnostic unit notifying the control unit and the vehicle control unit of an abnormality when the offset angle exceeds a predetermined value.
[0017] According to the electric motor device of the present invention, when the offset angle of the mounting position of the rotation angle sensor exceeds a predetermined value, an anomaly is notified to the control unit of the inverter control unit and the vehicle control unit, thereby enabling the relevant control units to take measures to prevent poor control of the electric motor device due to the offset of the rotation angle sensor.
[0018] In the fifth embodiment of the electric motor device of the present invention, the fourth embodiment is preferably described in which the inverter unit has a gate driver and a motor drive circuit including an upper arm and a lower arm, the control unit controls the switching elements included in the upper arm and the lower arm by outputting a signal to the gate driver, and the diagnostic unit notifies the control unit of an abnormality when the rotational speed of the electric motor unit exceeds a threshold, at which time the control unit performs fail-safe control.
[0019] In the fifth embodiment of the electric motor device of the present invention, the sixth embodiment preferably includes a fault-tolerant control that enables one of the upper arm and the lower arm to conduct in all phases and enables the other arm to disconnect in all phases. This is an active short circuit (ASC) control.
[0020] In the fifth embodiment, the seventh method of the electric motor device of the present invention preferably involves the fault-safe control being a shut-down (SD) control that disconnects both the upper arm and the lower arm in all phases.
[0021] When the motor rotates at high speed, the switching elements heat up. If the rotation angle sensor shifts and fails to accurately control the motor, the motor will accelerate further. According to the motor device of the present invention, fault-tolerant control (ASC control or SD control) is performed when the rotation angle sensor shifts and the motor rotates at high speed, thereby preventing the switching elements and battery from malfunctioning.
[0022] The eighth embodiment of the vehicle of the present invention includes an electric motor device according to any one of claims 1 to 7.
[0023] Invention Effects
[0024] The electric motor device according to the present invention can easily detect the physical offset of the rotation angle sensor in a software manner without additional external devices. Attached Figure Description
[0025] Figure 1 This is a schematic diagram illustrating the structure of the electric motor device of the present invention.
[0026] Figure 2 This is a schematic diagram showing the detailed structure of the calculation implementation condition determination unit and the rotary transformer offset angle calculation unit in the electric motor device of the present invention.
[0027] Figure 3 This is a schematic diagram illustrating a partial structure of the electric motor device in the fail-safe control of the present invention.
[0028] Figure 4 This is a schematic diagram illustrating the ASC control and SD control in the fail-safe control of this invention.
[0029] Figure 5 is a schematic diagram illustrating the physical angular offset of the rotary transformer relative to the rotor shaft. Detailed Implementation
[0030] The preferred embodiments of the electric motor device according to the present invention will now be described using the accompanying drawings. In the drawings, the same or equivalent parts are described using the same reference numerals.
[0031] <Structure of an electric motor>
[0032] Figure 1 This is a schematic diagram showing the structure of the electric motor device of the present invention. As an example, the electric motor device 10 of the present invention includes: an electric motor unit 300, an inverter unit 200, an inverter control unit (CPU) 110, and a rotation angle sensor 301.
[0033] The motor section 300 has a rotor and a stator, and is a motor driven to rotate by a three-phase alternating current supply. For example, the motor 300 may be a permanent magnet synchronous motor.
[0034] The rotation angle sensor 301 is fixed to the motor unit 300 and is used to detect the rotation angle of the motor unit 300. The rotation angle sensor 301 is, for example, a rotary transformer.
[0035] Figure 5A and Figure 5B This is a schematic diagram used to illustrate the physical angular offset of a rotary transformer relative to its rotor shaft. Figure 5A The image shows the normal condition where the rotary transformer 301 has no angular offset relative to the rotor shaft of the motor unit 300; Figure 5B The image shows an abnormal situation where the rotary transformer 301 is offset counterclockwise by an angle α relative to the rotor shaft of the motor unit 300.
[0036] The resolver 301 sends the detected resolver signal, including sine and cosine signals, to the RDC (resolver-to-digital converter) converter 400. The RDC converter 400 converts the resolver signal into a digital signal and sends it to the resolver offset angle calculation unit 104. The RDC converter 400 also sends the motor speed obtained from the resolver signal to the calculation implementation condition determination unit 103.
[0037] Inverter section 200 stores data in the battery ( Figure 1 The DC power (not shown) in the inverter section 300 is converted into three-phase AC power with variable voltage and variable frequency, and the converted three-phase AC power is supplied to the motor section 300. The inverter section 200 includes a current sensor 201, which detects the three-phase current in the inverter section 200 and provides the detected three-phase current to the inverter control section 110.
[0038] The inverter control unit 110 is provided in the inverter control circuit 100 and is used to control the inverter unit 200. The inverter control unit 110 includes a diagnostic unit 101, a control unit 102, a calculation implementation condition determination unit 103 (equivalent to a determination unit), and a resolver offset angle calculation unit 104 (equivalent to an arithmetic unit).
[0039] The calculation implementation condition determination unit 103 determines whether the rotary transformer offset angle calculation unit 104 is allowed to perform calculations based on the current flowing through the motor unit 300, the system state, and the rotational speed of the motor unit 300. The rotary transformer offset angle calculation unit 104 calculates the offset angle of the installation position of the rotation angle sensor 301 based on the difference between the measured and theoretical values of the voltage phase of the motor unit 300, and provides the calculated offset angle to the diagnostic unit 101. The specific operations of the calculation implementation condition determination unit 103 and the rotary transformer offset angle calculation unit 104 will be explained in detail later.
[0040] When the offset angle exceeds a predetermined value, the diagnostic unit 101 notifies the control unit 102 and the vehicle's microcomputer 500 (equivalent to the vehicle control unit) of an abnormality. Since the control unit 102 of the inverter control unit 110 and the vehicle control unit 500 are notified of an abnormality when the offset angle of the mounting position of the rotation angle sensor 301 exceeds the predetermined value, the relevant control units can be notified to take measures to prevent poor control of the motor unit due to the offset of the rotation angle sensor 301.
[0041] Upon receiving an abnormality notification from the diagnostic unit 101, the control unit 102 determines whether the rotational speed of the motor unit 300 exceeds, for example, 4000 rpm. If the rotational speed of the motor unit 300 does not exceed 4000 rpm, torque control is maintained. If the rotational speed of the motor unit 300 exceeds 4000 rpm, fail-safe control is initiated. The specific operation of fail-safe control will be explained in detail later.
[0042] <Specific Operations of the Implementation Condition Determination Unit and the Rotary Transformer Offset Angle Calculation Unit>
[0043] Figure 2This is a schematic diagram showing the detailed structure of the calculation implementation condition determination unit and the rotary transformer offset angle calculation unit in the electric motor device of the present invention.
[0044] The calculation implementation condition determination unit 103 determines whether the rotary transformer offset angle calculation unit 104 is allowed to perform calculations based on the current flowing through the motor unit 300, the system state, and the rotational speed of the motor unit 300.
[0045] Specifically, the CPU110 converts the three-phase current detected by the current sensor 201 into a d-axis current I. d and q-axis current I q The d-axis current I d and q-axis current I q Provided to the calculation implementation condition determination unit 103. d-axis current I d and q-axis current I q Used to calculate voltage vector V dq The voltage vector V dq This is the result obtained by vector synthesis of the d-axis and q-axis components. When either the d-axis or q-axis component is too large, the voltage phase cannot be detected. Therefore, as one of the conditions for calculation, I needs to be satisfied. d and I q The condition that neither side will be too large (hereinafter referred to as I) d ·I q condition).
[0046] Furthermore, the CPU 110 determines the state of the vehicle's microcomputer (VCU) 500, and the result of the determination is provided to the calculation implementation condition determination unit 103. Generally, it is desirable to detect whether the resolver has shifted only when the vehicle has started operating. Therefore, as another calculation implementation condition, the condition that the vehicle has started operating must be met (hereinafter referred to as the system state condition).
[0047] Furthermore, voltage phase cannot be detected when the motor speed is near 0 rpm. Therefore, as another condition for calculation implementation, it is necessary to satisfy the condition that the motor speed is not near 0 rpm (hereinafter referred to as the speed condition).
[0048] In other words, only when the above "I" is satisfied simultaneously d ·I q The calculation implementation condition determination unit 103 only allows the rotary transformer offset angle calculation unit 104 to perform calculations under the conditions of "system state conditions" and "speed conditions". As a result, the operation of the calculation implementation condition determination unit can be made more efficient, and the calculation of the offset angle of the installation position of the rotary transformer can be avoided when it is not necessary.
[0049] When the calculation implementation condition determination unit 103 allows the rotary transformer offset angle calculation unit 104 to perform calculations, the rotary transformer offset angle calculation unit 104 calculates the offset angle of the installation position of the rotation angle sensor 301 based on the difference between the measured value and the theoretical value of the voltage phase of the motor unit 300.
[0050] Specifically, the rotary transformer offset angle calculation unit 104 calculates the offset angle based on the d-axis current I. d q-axis current I q The motor winding resistance R, the motor angular velocity (electrical angular velocity) ω, the linkage flux Φ, and the d-axis inductance L. d q-axis inductance L q The voltage phase FF, which is the theoretical value, is calculated using the following Equation 1.
[0051] voltage phase
[0052] Furthermore, the rotary transformer offset angle calculation unit 104 calculates the actual d-axis voltage V based on the actual measured value. d and q-axis voltage V q The voltage phase FB, which is the measured value, is calculated using the following Equation 2.
[0053] voltage phase
[0054] Then, the rotary transformer offset angle calculation unit 104 calculates the difference between voltage phase FB and voltage phase FF to serve as the offset angle of the mounting position of the rotation angle sensor 301.
[0055] The rotary transformer offset angle calculation unit 104 provides the calculated offset angle to the diagnostic unit 101. When the offset angle exceeds a specified threshold (e.g., 30°), the diagnostic unit 101 notifies the control unit 102 and the vehicle's microcomputer 500 (equivalent to the vehicle control unit) of the abnormality.
[0056] Therefore, the electric motor device according to the present invention can easily detect the physical offset of the rotation angle sensor in a software manner without additional external devices.
[0057] <Specific Actions of Fail-Safe Control>
[0058] Figure 3 This is a schematic diagram illustrating a partial structure of the electric motor device in the fail-safe control of the present invention. Figure 4 This is a schematic diagram illustrating the ASC control and SD control in the fail-safe control of this invention.
[0059] like Figure 3As shown, the inverter section 200 includes a gate driver 24 and a motor drive circuit comprising an upper arm 22 and a lower arm 23. A high-voltage battery 13 supplies a high voltage to the inverter section 200, and a low-voltage battery 14 supplies a low voltage to the inverter control section 110. Here, the switching elements in the upper and lower arms are IGBTs, but the invention is not limited to this.
[0060] The control unit 102 in the inverter control unit 110 controls the switching elements contained in the upper arm 22 and lower arm 23 by outputting control signals to the gate driver 24. When the speed of the motor unit 300 does not exceed the threshold, the control unit 102 performs normal torque control, that is, controls the switching of the six switching elements of the upper arm 22 and lower arm 23 via the gate driver 24 in the inverter unit 200, so that the inverter unit 200 converts the DC power stored in the high-voltage battery into three-phase AC power with variable voltage and variable frequency, and supplies the converted three-phase AC power to the motor unit 300.
[0061] If the speed of the motor unit 300 exceeds the threshold, the diagnostic unit 101 notifies the control unit 102 of the abnormality. At this time, the control unit 102 ends the normal torque control and starts to execute fail-safe control.
[0062] The above-mentioned fail-safe controls can be as follows: Figure 4 The left side of the diagram shows ASC control, which enables one of the upper arm 22 and the lower arm 23 to be fully connected in one phase and the other to be fully disconnected in the other phase. By employing ASC control, the back electromotive force generated in the motor can be returned, preventing overcharging of the battery and preventing failure of the switching elements and the battery.
[0063] In addition, the above-mentioned fail-safe controls can also be implemented as follows: Figure 4 The right side of the diagram shows the SD control that enables both the upper arm 22 and the lower arm 23 to be fully disconnected. By employing SD control, it is possible to prevent failure of the switching elements and the battery.
[0064] When the motor rotates at high speed, the switching elements heat up. If the rotation angle sensor shifts and fails to accurately control the motor, the motor will accelerate further. Therefore, according to the motor device of the present invention, fault-tolerant control (ASC control or SD control) is performed when the rotation angle sensor shifts and the motor rotates at high speed, thereby preventing the switching elements and battery from malfunctioning.
[0065] Furthermore, the vehicle of the present invention includes the aforementioned electric motor device.
[0066] It should be understood that within the scope of this invention, the components in the embodiments can be freely combined, or the components in the embodiments can be appropriately modified or omitted.
[0067] As described above, the invention has been described in detail, but the above description is merely illustrative of all aspects, and the invention is not limited thereto. Numerous variations not illustrated are to be understood and are not departed from the scope of the invention.
[0068] Industrial practicality
[0069] The electric motor device involved in this invention can be widely used in fields such as electric motors for EVs (electric vehicles).
[0070] Label Explanation
[0071] 10. Electric motor assembly;
[0072] 100 Inverter control circuit;
[0073] 110 Inverter Control Unit (CPU);
[0074] 101 Diagnostic Department;
[0075] 102 Control Department;
[0076] 103. Calculation Implementation Condition Determination Department;
[0077] 104 Rotary Transformer Offset Angle Calculation Unit;
[0078] 200 Inverter Division;
[0079] 201 Current sensor;
[0080] 300 Electric Motor Section;
[0081] 301 Rotary Transformer;
[0082] 400 RDC converter;
[0083] Microcomputers in 500 vehicles;
[0084] 13. High-voltage battery;
[0085] 14. Low-voltage battery;
[0086] 22. Upper arm;
[0087] 23. Lower arm;
[0088] 24 Gate drivers.
Claims
1. An electric motor device, comprising: The electric motor section has a rotor and a stator; The inverter section is used to convert the input voltage into a three-phase AC voltage and supply it to the motor section; Inverter control unit; the inverter control unit is used to control the inverter unit; and A rotation angle sensor, fixed to the motor unit, is used to detect the rotation angle of the motor unit. The inverter control unit includes an arithmetic unit that calculates the measured value of the voltage phase of the motor unit based on the detected voltage value of the motor unit, calculates the theoretical value of the voltage phase of the motor unit based on the rotation angle of the motor unit detected by the rotation angle sensor, and calculates the offset angle of the installation position of the rotation angle sensor based on the difference between the measured value and the theoretical value.
2. The electric motor device as claimed in claim 1, characterized in that, The inverter control unit also includes a decision unit that determines whether the calculation unit is allowed to perform calculations. When the determination unit allows the calculation unit to perform calculations, the calculation unit calculates the offset angle of the mounting position of the rotation angle sensor.
3. The electric motor device as described in claim 2, characterized in that, The determination unit determines whether the calculation unit is allowed to perform calculations based on the current flowing through the motor unit, the system state, and the rotational speed of the motor unit.
4. The electric motor device as claimed in claim 1, characterized in that, The electric motor unit is mounted on a vehicle equipped with a vehicle control unit. The inverter control unit also includes a diagnostic unit and a control unit. When the offset angle exceeds a predetermined value, the diagnostic unit notifies the control unit and the vehicle control unit of the abnormality.
5. The electric motor device as described in claim 4, characterized in that, The inverter section includes motor drive circuits for an upper arm and a lower arm. The control unit controls the switching elements contained in the upper arm and the lower arm to switch on and off. When the rotational speed of the motor exceeds a threshold, the diagnostic unit notifies the control unit of an abnormality, at which point the control unit performs fail-safe control.
6. The electric motor device as described in claim 5, characterized in that, The fault-safe control is a control that enables one of the upper arm and the lower arm to be fully connected in one phase and the other to be fully disconnected in the other phase.
7. The electric motor device as claimed in claim 5, characterized in that, The fail-safe control is a control that causes both the upper arm and the lower arm to be completely disconnected.
8. A vehicle, characterized in that, The electric motor device includes any one of claims 1 to 7.