Motor vector control method, method for heating vehicle battery pack and motor inverter
By introducing high-frequency current components into the motor, improving the heating efficiency of the motor and replacing the traditional AVAS system, the problems of low battery pack heating efficiency and high manufacturing cost of electric vehicles in cold environments are solved, and more efficient motor heating and reduction are achieved Manufacturing cost.
Patent Information
- Application Number
- CN202310708676.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-15
- Publication Date
- 2024-12-17
AI Technical Summary
In cold environments, the charging and discharging capacity of the electric vehicle battery pack is limited due to low temperature, which affects driving performance. The motor power devices are prone to overtemperature when driving at low speeds, resulting in low heating efficiency. At the same time, the transmission system needs to be low at low speeds. Additional AVAS systems increase manufacturing costs.
The motor vector control method is adopted to increase the stator coil loss and iron loss by introducing high-frequency current components into the motor to achieve more efficient heating, and use electromagnetic noise to replace traditional AVAS systems to reduce manufacturing costs.
It effectively improves the heating efficiency of the motor under low-speed operating conditions, avoids overtemperature of power devices, reduces manufacturing costs, and maintains the stability of motor torque.
Smart Images
Figure CN119154745A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of motor control, and more specifically, to a motor vector control method, a method for heating a vehicle battery pack using the vector control method during driving, and a motor inverter. Background Art
[0002] At present, when new energy vehicles (such as electric vehicles) are driven in severe cold conditions, the vehicle battery pack (especially the power battery) is affected by the low temperature environment, resulting in limited charging and discharging capabilities, which in turn affects the overall driving performance of the vehicle. Therefore, the vehicle battery pack needs to be heated in cold environments.
[0003] For the heating of moving vehicles, a pre-calibrated current table is usually used to run the motor in a low-efficiency section, and the motor stator is heated by a large current. The stator heat is used to directly heat the cooling water circuit, and then the heated cooling water flows through the battery pack to heat the vehicle battery pack.
[0004] During the above heating process, if a component of the vehicle (especially the motor) overheats, the heating current needs to be derated. For example, when an electric vehicle is running at low speed and high current, power devices such as IGBT in the motor are very easy to overheat, resulting in current derated, so the heating effect of the coolant is not ideal at low speed. When the motor is running under low speed and high torque conditions, since power devices such as IGBT heat up quickly, the system quickly enters the overtemperature derated program, so the heating efficiency of the battery is not high at low speed.
[0005] Another problem with electric vehicles is that when the vehicle is traveling at a low speed, since the transmission system makes very little noise at a low speed, an AVAS (Acoustic Vehicle Alerting System) system is generally installed on the vehicle to warn pedestrians. This system requires the addition of additional power supply and generating devices and is controlled through CAN communication, which increases the manufacturing cost of the vehicle. Summary of the invention
[0006] In view of this, according to a first aspect of the present invention, a motor vector control method is proposed, the method comprising the following steps:
[0007] Step S1, obtaining the power loss requirement of the motor from the vehicle VCU Based on the power loss requirement and the rated frequency F inside the motor oft Determine the DC fundamental component I of the current to be applied to the motor S ;
[0008] Step S2, using an AC signal generator to generate a signal with the calibration frequency F oft The AC component I Sa ;
[0009] Step S3, the AC component I generated in step S2 Sa Superimposed on the DC fundamental component I S To determine the AC and DC composite current I to be applied to the motor s，c o m ;
[0010] Step S4, determine the given torque of the motor Rotor temperature T rotor , motor speed w and the DC side voltage U of the motor inverter dc ;
[0011] Step S5, based on the given torque of the motor Rotor temperature T rotor , motor speed w, DC side voltage U of motor inverter dc And the DC fundamental component I S , determine the DC control component in the motor dq axis current
[0012] Step S6, based on the given torque of the motor Rotor temperature T rotor , motor speed w, DC side voltage U of motor inverter dc The AC / DC composite quantity I s，com and the DC control component determined in step S5 Determine the AC control component in the motor dq axis current as well as
[0013] Step S7, based on the DC control component and the AC control component Control the operation of the motor.
[0014] According to an advantageous embodiment, step S5 further comprises:
[0015] Based on the DC side voltage U of the motor inverter dc Determine the stator flux limit related value with the motor speed w
[0016] The given torque The rotor temperature T rotor And the DC fundamental component I S Input into the first lookup table T1 to determine the first stator flux lookup table value
[0017] Based on the stator flux limitation related value and the first stator flux linkage table value Re-determine the first stator flux as well as
[0018] The given torque The rotor temperature T rotor and the first stator flux Input into the second lookup table T2 to determine the DC control component
[0019] According to an advantageous embodiment, step S6 further comprises:
[0020] The given torque The rotor temperature T rotor And in the AC / DC composite quantity I s，com Input into the third lookup table T3 to determine the second stator flux lookup table value
[0021] Based on the stator flux limitation related value and the second stator flux table value Re-determine the second stator flux as well as
[0022] The given torque The rotor temperature T rotor and the second stator flux Input into the fourth lookup table T4 to determine the synthetic control amount of the motor dq axis current;
[0023] The DC control component determined in step S5 is subtracted from the combined control amount. To obtain the AC control component
[0024] According to an advantageous embodiment, the method further comprises:
[0025] Determine the DC component feedback value Id of the motor dq axis current dc， Iq dc ;and
[0026] Using the first controller based on the DC component feedback value Id dc， Iq dc The DC component in the motor dq axis current is controlled in a closed loop.
[0027] According to an advantageous embodiment, the method further comprises:
[0028] Determine the AC component feedback value Id of the motor dq axis current ac , Iq ac ;and
[0029] The second controller is used based on the AC component feedback value Id ac , Iq ac The AC component in the motor dq axis current is controlled in a closed loop.
[0030] According to an advantageous embodiment, the DC component feedback value Id dc , Iq dc and the AC component feedback value Id ac , Iq ac According to the three-phase current I of the motor a，b，c , rotor angle θ and the calibration frequency F oft Calculated.
[0031] According to an advantageous embodiment, the first controller is a PI controller and the second controller is a PR controller.
[0032] According to an advantageous embodiment, the AC component I Sa The calibration frequency F oft It is determined based on the current motor speed w.
[0033] According to a second aspect of the present invention, there is also provided a method for heating a vehicle battery pack during driving, the method comprising the following steps:
[0034] Detecting the temperature of a battery cell in a vehicle battery pack and determining whether the temperature of the battery cell is lower than a set value; and
[0035] When the battery cell temperature is lower than the set value, the motor current is adjusted using the motor vector control method as described above to heat the vehicle battery pack.
[0036] According to a third aspect of the present invention, a motor inverter is further provided, the motor inverter comprising:
[0037] A sampling module, the sampling module is used to collect at least one state information of the motor;
[0038] A controller, the controller being configured to control the motor current by using the motor vector control method as described above according to the at least one state information of the motor; and
[0039] A driving unit is configured to drive the motor accordingly based on the motor current provided by the controller.
[0040] The motor vector control method according to the present invention can be applied in the field of vehicle battery pack heating to achieve effective heating of the vehicle battery pack. In particular, the method can provide iron loss while providing stator coil loss (ie, copper loss) by introducing high-frequency current components, thereby utilizing iron loss to improve the efficiency of motor heating, which to a certain extent avoids the problem of system over-temperature derating caused by overheating of power devices at low speeds. In addition, under low-speed conditions, the method can utilize variable AC current amplitude to ensure the stability of the IGBT junction temperature rise, thereby avoiding the problem of current derating to a certain extent. In addition, the motor vector control method can generate electromagnetic noise by adding high-frequency AC current components, so that when the vehicle is traveling at low speeds, it can replace the traditional AVAS system to make the vehicle sound, thereby reducing the manufacturing cost of the vehicle and will not cause fluctuations in the motor torque. BRIEF DESCRIPTION OF THE DRAWINGS
[0041] By incorporating the accompanying drawings and Figure 1 With reference to the specific embodiments used to illustrate certain principles of the present invention, other features and advantages of the method of the present invention will become clear or be described in more detail.
[0042] Figure 1 A curve diagram showing the changes in various motor parameters during motor vector control.
[0043] Figure 2 A schematic diagram for determining a table lookup input in a motor vector control method according to the present invention is shown.
[0044] Figure 3 A waveform diagram of the motor AC current frequency at lower motor speeds is shown.
[0045] Figure 4 A waveform diagram showing the motor AC current frequency at higher motor speeds.
[0046] Figure 5 A schematic diagram showing a control architecture of a motor vector control method according to the present invention is shown.
[0047] Figure 6 A flow chart of a motor vector control method according to an exemplary embodiment of the present invention is shown. DETAILED DESCRIPTION
[0048] The motor vector control method according to the present invention will be described below with reference to the accompanying drawings and by way of example. In the following description, many specific details are set forth so that a person skilled in the art can more fully understand the present invention. However, it is obvious to a person skilled in the art that the present invention may be implemented without some of these specific details. Instead, any combination of the following features and elements may be considered to implement the present invention, regardless of whether they relate to different embodiments. Therefore, the following aspects, features, embodiments and advantages are for illustrative purposes only and should not be regarded as elements or limitations of the claims.
[0049] The applicant has found that for electric vehicles including three-phase AC motors, the conventional method of heating the power battery is to control the three-phase inverter so that the motor generates heat according to the heating energy to heat the coolant flowing through the power battery when the current temperature value of the power battery is lower than the preset temperature value and meets the preset conditions, and obtain the preset cross-axis current so that the torque value output by the motor is at an appropriate value, and obtain the corresponding preset direct-axis current according to the power battery heating power, and then control the three-phase inverter to adjust the phase current of the three-phase AC motor according to the preset direct-axis current and the preset cross-axis current during the heating process.
[0050] Regarding the battery heating problem of a moving vehicle, when the vehicle's motor is running under low speed and high torque conditions, the power devices such as IGBTs heat up very quickly, causing the system to easily enter the over-temperature derating program, resulting in low heating efficiency for the battery.
[0051] Based on the above background, the present invention proposes a motor vector control method, which can be applied to heating a vehicle battery pack (especially a moving vehicle). In the design of the vector control method, in addition to retaining the conventional AC and DC axis current id, iq table lookup and PI closed-loop control method, the method also adds a high-frequency (AC) current control loop, and adds a current table lookup program based on power / current instructions. The program adds an AC bias to the given current input end of the table lookup to achieve high-frequency current control, thereby achieving high-frequency heating of the motor and then the vehicle battery pack.
[0052] In addition, the motor vector control method generates electromagnetic noise by adding high-frequency AC current components, which can replace the traditional AVAS system to make the vehicle sound when the vehicle is driving at low speed, reducing the manufacturing cost of the vehicle. The basic principle of this scheme is that the electromagnetic noise of the motor is related to the frequency, order and amplitude of the electromagnetic force wave generated by the air gap magnetic field. When the radial electromagnetic force wave frequency is close to the stator modal frequency, a smaller excitation will also produce a larger vibration. When the radial force wave frequency deviates from the stator modal frequency, the amplitude of the harmonic needs to be increased to increase the volume of the warning sound. When driving at low speed, based on the reference torque, high-frequency current harmonics are superimposed on the original three-phase current, and the high-frequency current harmonics generate noise of different frequencies inside the motor. The reference value of the current needs to slide along the equal torque curve to generate the current of the AC component, which can ensure the stability of the motor torque. In other words, electromagnetic noise can be generated by adding a high-frequency AC component to the motor current, but the actual torque of the motor will not produce too much difference and fluctuation.
[0053] Figure 1 The graph shows the changes of various motor parameters during the motor vector control process. Figure 1 In the figure, the voltage ellipse, current circle and equal torque curve are marked. In the vector control process of the motor, it is hoped to achieve the maximum torque output under a given current amplitude, that is, to achieve the MTPA (Maximum Torque Per Ampere) condition. The MTPA condition is achieved by optimizing the flux and current vector of the motor so that the motor can produce the maximum output torque with the highest efficiency. Under the MTPA condition, the controller will adjust the flux and current vector of the motor according to the working state and load requirements of the motor to make it close to the value of the maximum stator flux and keep the current amplitude within the rated range. By reasonably controlling the flux and current of the motor, the maximum output torque can be achieved under a given current limit, thereby improving the efficiency and performance of the motor.
[0054] exist Figure 1 In the figure, the MTPA point is the tangent point of the current circle and the equal torque curve. When the battery heating program needs to be entered under the MTPA condition, the required AC current amplitude and frequency are obtained according to the power loss requirements set for the motor and other motor parameters. The process can be seen in Figure 2 .
[0055] Figure 2 FIG. 2 shows a schematic diagram for determining a table lookup input in a motor vector control method according to the present invention. Figure 2 As shown in , the current value Is is requested based on the power loss requirement requested by the VCU and the rated frequency inside the motor. The AC generator adds the AC current value to the given DC Is to ensure that the given current contains an AC component.
[0056] Specifically, according to the power loss requirements of the motor and the calibration frequency Foft, the DC fundamental component I of the current to be applied to the motor can be determined S In addition, an AC signal generator can be used to generate a signal with a calibrated frequency F oft The AC component I Sa The calibration frequency F oft For example, it can be determined according to the frequency of the current motor speed w, that is, according to the different motor speeds, the AC component I can be freely set Sa Frequency F oft .
[0057] refer to Figure 3 and Figure 4 , which respectively show the waveform of the motor AC current frequency at a lower motor speed and the waveform of the motor AC current frequency at a higher motor speed. That is, according to the target frequency ratio between the current AC signal and the motor speed (which can be preset by the user), when the motor is running at a lower speed, a similar Figure 3 The control method is adopted to ensure the consistency of the effective value of the current and ensure that the junction temperature of the IGBT can maintain a stable temperature rise under the periodic change of the current. When the motor is running at a higher speed, a similar Figure 4 control method, thereby increasing the motor iron loss, which helps to heat the motor itself and the vehicle battery pack.
[0058] Figure 5 The schematic diagram of the control architecture of the motor vector control method according to the present invention is shown. In the motor vector control method, a current control mode is adopted, and an AC current control loop is added in addition to a conventional DC control loop.
[0059] like Figure 5 As shown in , the architecture calibrates a table (T2, T4) with stator flux as input. The purpose of this table is to change the voltage ellipse to ensure that the current lookup table moves from the normal lookup table position along the equal torque curve to the weak magnetic direction. The current point in the weak magnetic area is the intersection of the equal torque curve and the voltage circle. The input point of the current lookup table is limited by the current circle. The direction of the input point of the current lookup table can be seen in Figure 1 .
[0060] Usually, in the current lookup table, the given torque is used Stator flux and rotor temperature T rotor As the input of the current lookup table, the current lookup table value is determined. However, in actual applications, in order to avoid the complexity of the 4-dimensional table and to be able to switch between heating and non-heating functions at will, the stator flux limit related values will be recalculated To determine the new stator flux As a table input. The stator flux can be determined based on the following equation:
[0061]
[0062] in, is the given torque of the motor, is the rotor flux, U dc is the DC side voltage of the motor inverter, w is the motor speed, i d ,i q is the AC and DC current amplitude (which can be obtained by Figure 2 The table shown is used to determine), L d , L q is the motor inductance, and the stator flux The value and ratio U dc / w related.
[0063] Based on the above equation, the new stator flux value is obtained According to the new stator flux value Look up the normal current table (ie, T2, T4) to determine the control input value for the motor current.
[0064] Since it is not possible to find the appropriate pure AC component on the equal torque curve under the motor characteristic diagram, the DC control component in the motor dq axis current is obtained by looking up tables T1 and T2. The DC control component can be input into the PI controller to adjust the DC component in the AC and DC axis current. The AC and DC composite control quantity is obtained through Tables 3 and 4. The DC component is then fed back to the AC closed-loop control loop to extract the pure AC control component. This allows for better use of the PR controller to regulate the control of the AC current portion.
[0065] In order to achieve closed-loop control, it is necessary to obtain the feedback value of AC and DC current in real time. The feedback value can also be based on Figure 2 The table shown in is used to determine, that is, by the motor position angle θ, the calibration frequency F oft The actual three-phase current I a，b，c Extract AC and DC components to obtain the DC component Id of the dq current dc , Iq dc and AC component ID ac , Iq ac , these two components can be fed back to the PI controller and the PR controller respectively to realize closed-loop feedback control of the motor current, thereby ensuring accurate tracking and control of the motor dq current.
[0066] Figure 6A flow chart of a motor vector control method according to an exemplary embodiment of the present invention is shown. Figure 6 To describe in detail the various operating steps of the vector control method.
[0067] First, in step S1, the power loss requirement of the motor is obtained from the vehicle VCU. Based on the power loss requirement and the rated frequency F inside the motor oft Determine the DC fundamental component I of the current to be applied to the motor S Among them, the calibration frequency F oft For example, it can be determined according to the current motor speed so that the calibration frequency F oft The predetermined frequency ratio is satisfied with the motor speed.
[0068] In step S2, an AC signal generator is used to generate a signal having the above F oft The AC component I Sa , and the AC component I generated in step S2 Sa Superimposed on the DC fundamental wave component I determined in step S1 S To determine the AC and DC composite current I to be applied to the motor s，com .
[0069] Further, in step S4, the given torque of the motor is determined Rotor temperature T rotor , motor speed w and the DC side voltage U of the motor inverter dc .
[0070] Then, in step S5, based on the given torque of the motor Rotor temperature T rotor , motor speed w, DC side voltage U of motor inverter dc And the DC fundamental component I S , determine the DC control component in the motor dq axis current
[0071] Specifically, step S5 includes the following process:
[0072] - Based on the DC link voltage U of the motor inverter dc Determine the stator flux limit related value with the motor speed w In particular, the limit-related values Defined as the DC side voltage U of the motor inverter dc The ratio between the motor speed w, that is, U dc / w;
[0073] - Set the given torque Rotor temperature Trotor And the DC fundamental component I S Input into the first lookup table T1 to determine the first stator flux lookup table value as well as
[0074] -Based on the stator flux limit related values And the first stator flux table value Re-determine the new first stator flux The new first stator flux For example, by taking and The minimum value among them is obtained;
[0075] - Set the given torque Rotor temperature T rotor and the first stator flux Input into the second lookup table T2 to determine the DC control component in the motor dq axis current
[0076] After determining the DC control component Then, in step S6, based on the DC control component And the given torque of the motor Rotor temperature T roto r, motor speed w, DC side voltage U of motor inverter dc The AC / DC composite quantity I s，com , the AC control component in the motor dq axis current can be further determined in step S6
[0077] Specifically, step S6 may include the following process:
[0078] - Set the given torque Rotor temperature T rotor And in the AC and DC composite quantity I s，com Input into the third lookup table T3 to determine the second stator flux lookup table value
[0079] -Based on the stator flux limitation related value And the second stator flux table value Re-determine the new second stator flux as well as
[0080] - Set the given torque Rotor temperature T rotor and the second stator flux Input into the fourth lookup table T4 to determine the synthetic control amount of the motor dq axis current; and
[0081] - Subtract the DC control component determined in step S5 from the composite control amount To obtain the AC control component
[0082] After determining the DC control component and the AC control component The operation of the motor may be controlled based on the current value (eg, generating a corresponding control voltage) in step S7 .
[0083] According to an optional embodiment, in order to more accurately control the motor, the feedback value of the AC and DC current can be obtained in real time. The feedback value can also be based on Figure 2 That is, the motor position angle θ, the calibration frequency F oft The actual three-phase current I a，b，c Extract AC and DC components to obtain the DC component feedback value Id of the dq current dc , Iq dc And AC component feedback value Id ac , Iq ac , these two component feedback values can be fed back to the PI controller and the PR controller respectively to realize closed-loop feedback control of the DC component and the AC component respectively, thereby ensuring accurate tracking and control of the motor dq current.
[0084] The motor vector control method according to the present invention can be applied in the field of vehicle battery pack heating to achieve effective heating of the vehicle battery pack. In particular, the method can provide iron loss while providing stator coil loss (i.e., copper loss) by introducing a high-frequency current component, thereby utilizing the iron loss to improve the efficiency of motor heating, which to a certain extent avoids the problem of system over-temperature derating caused by overheating of power devices at low speeds. In addition, the motor vector control method can generate electromagnetic noise by adding a high-frequency AC current component, so that it can replace the traditional AVAS system to make the vehicle sound when the vehicle is traveling at a low speed, thereby reducing the manufacturing cost of the vehicle and will not cause fluctuations in the motor torque.
[0085] A preferred embodiment of the present invention also provides a motor inverter, which includes a sampling module for collecting at least one state information of the motor; a controller for controlling the motor current according to at least one state information of the motor and using the motor vector control method described in the above embodiment of the present invention; and a drive unit for driving the motor accordingly according to the motor current provided by the controller.
[0086] In this article, the "dq axis" of the motor refers to the direct axis and quadrature axis of the motor, where the direct axis is also called the d axis, which is aligned with the direction of the motor rotor magnetic field; and the quadrature axis is also called the q axis, which is perpendicular to the direction of the motor rotor magnetic field. Therefore, it can be understood by those skilled in the art that the term "dq axis current (or inductance)" refers to the d axis current (or inductance) and the q axis current (or inductance). For example, the "DC component Id" in this article dc， Iq dc ” includes the DC component Id of the direct axis dc and the DC component of the quadrature axis Iq dc , and the "AC component Id ac , Iq ac "Including the direct-axis AC component Id ac and the AC component Iq of the quadrature axis ac .
[0087] Those skilled in the art will appreciate that the various steps of the method according to the present invention are not limited to being implemented in the order listed above. In addition, in the present invention, the terms "comprise" and "include" indicate that in addition to the steps directly and clearly stated in the specification and claims, the technical solution of the present application does not exclude the situation of having other steps that are not directly or clearly stated.
[0088] Although the present invention has been disclosed as above with preferred embodiments, the present invention is not limited thereto. Any changes and modifications made by any person skilled in the art without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention, and therefore the protection scope of the present invention should be subject to the scope defined by the claims.
Claims
1. A motor vector control method, characterized in that: The method comprises the following steps: Step S1, obtaining the power loss requirement of the motor from the vehicle VCU Based on the power loss requirement and the rated frequency F inside the motor oft Determine the DC fundamental component I of the current to be applied to the motor S ; Step S2, using an AC signal generator to generate a signal with the calibration frequency F oft The AC component I Sa ; Step S3, the AC component I generated in step S2 Sa Superimposed on the DC fundamental component I S To determine the AC and DC composite current I to be applied to the motor s，com ; Step S4, determine the given torque of the motor Rotor temperature T rotor , motor speed w and the DC side voltage U of the motor inverter dc ; Step S5, based on the given torque of the motor Rotor temperature T rotor , motor speed w, DC side voltage U of motor inverter dc And the DC fundamental component I S , determine the DC control component in the motor dq axis current Step S6, based on the given torque of the motor Rotor temperature T rotor , motor speed w, DC side voltage U of motor inverter dc The AC / DC composite quantity I s，com and the DC control component determined in step S5 Determine the AC control component in the motor dq axis current as well as Step S7, based on the DC control component and the AC control component Control the operation of the motor.
2. The motor vector control method according to claim 1, characterized in that: The step S5 further comprises: Based on the DC side voltage U of the motor inverter dc Determine the stator flux limit related value with the motor speed w The given torque The rotor temperature T rotor And the DC fundamental component I S Input into the first lookup table T1 to determine the first stator flux lookup table value Based on the stator flux limitation related value and the first stator flux linkage table value Re-determine the first stator flux as well as The given torque The rotor temperature T rotor and the first stator flux Input into the second lookup table T2 to determine the DC control component 3. The motor vector control method according to claim 2, characterized in that: The step S6 further comprises: The given torque The rotor temperature T rotor And in the AC / DC composite quantity I s，com Input into the third lookup table T3 to determine the second stator flux lookup table value Based on the stator flux limitation related value and the second stator flux table value Re-determine the second stator flux as well as The given torque The rotor temperature T rotor and the second stator flux Input into the fourth lookup table T4 to determine the synthetic control amount of the motor dq axis current; The DC control component determined in step S5 is subtracted from the combined control amount. To obtain the AC control component 4. The motor vector control method according to any one of claims 1 to 3, characterized in that: The method further comprises: Determine the DC component feedback value Id of the motor dq axis current dc , Iq dc ;and Using the first controller based on the DC component feedback value Id dc , Iq dc The DC component in the motor dq axis current is controlled in a closed loop.
5. The motor vector control method according to claim 4, characterized in that: The method further comprises: Determine the AC component feedback value Id of the motor dq axis current ac , Iq ac ;and The second controller is used based on the AC component feedback value Id ac , Iq ac The AC component in the motor dq axis current is controlled in a closed loop.
6. The motor vector control method according to claim 4, characterized in that: The DC component feedback value Id dc , Iq dc and the AC component feedback value Id ac , Iq ac According to the three-phase current I of the motor a，b，c , rotor angle θ and the calibration frequency F oft Calculated.
7. The motor vector control method according to claim 5 or 6, characterized in that: The first controller is a PI controller, and the second controller is a PR controller.
8. The motor vector control method according to any one of claims 1 to 3, characterized in that: The AC component I Sa The calibration frequency F oft It is determined based on the current motor speed w.
9. A method for heating a vehicle battery pack during driving, characterized in that: The method comprises the following steps: Detecting the temperature of a battery cell in a vehicle battery pack and determining whether the temperature of the battery cell is lower than a set value; and When the battery cell temperature is lower than the set value, the motor current is adjusted using the motor vector control method according to any one of claims 1 to 8 to heat the vehicle battery pack.
10. A motor inverter, characterized in that: The motor inverter includes: A sampling module, the sampling module is used to collect at least one state information of the motor; A controller, wherein the controller is configured to control the motor current according to the at least one state information of the motor by using the motor vector control method according to any one of claims 1 to 8; and A driving unit is configured to drive the motor accordingly based on the motor current provided by the controller.