Battery self-heating method, electronic device, and storage medium

Abstract

The application provides a battery self-heating method, an electronic device and a storage medium, wherein the battery self-heating method comprises the following steps: calculating a direct current component of a motor current based on a required torque and a battery self-heating requirement; determining a high-frequency current component, which is an alternating current component; superimposing the high-frequency alternating current component and the direct current component, so that the motor current carries the high-frequency alternating current component; and controlling the motor to heat the battery based on the motor current, wherein the direct current component is generated by a direct current voltage vector control in a DQ coordinate system, and the high-frequency current component is generated by a high-frequency alternating current voltage control superimposed on the direct current voltage vector in the DQ coordinate system. The application can heat the battery in a driving state.

Description

Technical Field

[0001] This application relates to the field of battery heating, and more specifically, to a battery self-heating method, electronic device, and storage medium. Background Technology

[0002] Electric vehicle batteries perform poorly at low temperatures, requiring rapid heating to improve the user experience. Battery AC heating technology (also known as battery self-heating technology or battery pulse heating technology) involves applying alternating current to the battery, utilizing its internal resistance to generate heat. This method offers advantages such as high heating power, uniform heating, and high heating efficiency, making it an important low-temperature battery heating technology.

[0003] Currently, existing battery AC heating technology requires the motor to be stationary, meaning that existing battery AC heating technology cannot heat the battery while the vehicle is in motion. Summary of the Invention

[0004] The purpose of this application is to provide a battery self-heating method, electronic device, and storage medium for heating the battery while driving.

[0005] In a first aspect, the present invention provides a battery self-heating method, the method comprising:

[0006] The DC component of the motor current is calculated based on the required torque and the battery self-heating requirement.

[0007] Determine the high-frequency current component, which is the alternating current component;

[0008] The high-frequency AC component is superimposed with the DC component so that the motor current carries the high-frequency AC component.

[0009] The motor heats the battery based on motor current control. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system.

[0010] The method of the first aspect of this application can calculate the DC component of the motor current based on the required torque and the battery's self-heating requirements, and determine the high-frequency current component, which is an AC current component. The high-frequency AC component is then superimposed on the DC component, so that the motor current carries the high-frequency AC component. This allows the motor to be controlled to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system. Compared with existing technologies, this application can meet the heating and torque requirements during driving by using the DC component of the motor current, thus keeping the vehicle in a driving state. Simultaneously, the high-frequency AC component of the motor current can cause high-frequency changes in the energy storage of the motor windings and the motor output power, thereby generating high-frequency AC current on the DC bus side of the inverter. This high-frequency AC current is then used to charge the battery, ultimately achieving battery charging while the vehicle is in motion.

[0011] In an optional implementation, the DC component includes a D-axis DC component and a Q-axis DC component, and the high-frequency AC component includes a D-axis AC component and a Q-axis AC component, wherein the D-axis AC component is superimposed on the D-axis DC component, and the Q-axis AC component is superimposed on the Q-axis DC component.

[0012] In an optional implementation, the torque generated by the DC component is equal to the required torque.

[0013] In an optional implementation, the DC component of the motor current is calculated based on the required torque and the battery self-heating requirement, including:

[0014] The pre-selected current operating point is determined based on the required torque and battery self-heating requirements in the maximum torque-current ratio line.

[0015] Determine the isotorque curve at the pre-selected current operating point;

[0016] Determine the weakening current point or the magnetizing current point based on the equitor lines of the pre-selected current operating point;

[0017] Select the current operating point whose current amplitude meets the preset conditions from either the weakening current point or the strengthening current point as the DC component of the motor current.

[0018] In an optional implementation, the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system is generated by the alternating changes of a first voltage vector and a second voltage vector in the DQ coordinate system. The first voltage vector is located on the maximum available voltage boundary, and the second voltage vector is located within the maximum available voltage boundary. The maximum available voltage boundary is the limit on the voltage output from the inverter to the motor, which is limited by the DC bus voltage. Furthermore:

[0019] U dqL =2Udq0 – U dqH ;

[0020] U dqL U represents the second voltage vector. dqH This represents the first voltage vector, with Udq0 being the DC component.

[0021] In an optional implementation, the method further includes: obtaining, through experimentation or simulation, or by using an approximate simplified mathematical model, the value of U that maximizes the energy storage fluctuation amplitude of the motor winding. dqH .

[0022] In an optional implementation, the fundamental frequency of the high-frequency current component is equal to 10% to 300% of the resonant frequency of the parallel resonant circuit, wherein the parallel resonant circuit is composed of the inverter DC bus capacitor, the stray inductance between the battery and the inverter, and the battery internal resistance.

[0023] A second aspect of this application discloses a battery self-heating device, the device comprising:

[0024] The first calculation module is used to calculate the DC component of the motor current based on the required torque and the battery self-heating requirement.

[0025] The determination module is used to determine the high-frequency current component, which is an alternating current component.

[0026] The second calculation module is used to superimpose the high-frequency AC component with the DC component so that the motor current carries the high-frequency AC component.

[0027] The control module is used to control the motor to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system.

[0028] Thirdly, the present invention provides an electronic device, comprising:

[0029] Processor; and

[0030] The memory is configured to store machine-readable instructions that, when executed by a processor, perform the battery self-heating method as described in any of the foregoing embodiments.

[0031] Fourthly, the present invention provides a storage medium storing a computer program, the computer program being executed by a processor of a battery self-heating method as described in any of the foregoing embodiments. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic flowchart of a battery self-heating method disclosed in an embodiment of this application;

[0034] Figure 2 This is a schematic diagram of the DC-side current relationship in a driving state disclosed in an embodiment of this application;

[0035] Figure 3 This is a schematic diagram of the DQ-axis current trajectory after superimposed AC components, as disclosed in an embodiment of this application.

[0036] Figure 4 This is a schematic diagram of an isotorque line disclosed in an embodiment of this application;

[0037] Figure 5 This is a schematic diagram of the possible range of voltage vectors disclosed in an embodiment of this application;

[0038] Figure 6 This is a schematic diagram of another possible voltage vector range disclosed in an embodiment of this application;

[0039] Figure 7 This is a calculation result diagram of a DC component located on the MTPA line, as disclosed in an embodiment of this application;

[0040] Figure 8 This is a calculation result diagram for Id=-200A disclosed in an embodiment of this application;

[0041] Figure 9 This is a calculation result diagram for Id=-400A disclosed in an embodiment of this application;

[0042] Figure 10 This is a calculation result diagram for Id=-600A disclosed in an embodiment of this application;

[0043] Figure 11 This is a schematic diagram of the structure of a battery self-heating device disclosed in an embodiment of this application;

[0044] Figure 12 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this application. Detailed Implementation

[0045] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0046] Example 1

[0047] Please see Figure 1 , Figure 1 This is a schematic flowchart of a battery self-heating method disclosed in an embodiment of this application, as shown below. Figure 1 As shown, the method in this application embodiment includes the following steps:

[0048] 101. Calculate the DC component of the motor current based on the required torque and the battery self-heating requirement;

[0049] 102. Determine the high-frequency current component, which is the alternating current component;

[0050] 103. Superimpose the high-frequency AC component with the DC component so that the motor current carries the high-frequency AC component;

[0051] 104. The motor heats the battery based on motor current control, wherein the DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system.

[0052] The method of this application embodiment can calculate the DC component of the motor current and determine the high-frequency current component based on the required torque and battery self-heating requirements. The high-frequency current component is an AC current component. The high-frequency AC component is then superimposed on the DC component, so that the motor current carries the high-frequency AC component. This allows the motor to control the heating of the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system. Compared with the prior art, this application can meet the heating and torque requirements during driving by using the DC component of the motor current, thus keeping the vehicle in a driving state. Simultaneously, the high-frequency AC component of the motor current can cause high-frequency changes in the energy storage of the motor windings and the motor output power, thereby generating high-frequency AC current on the DC bus side of the inverter. This high-frequency AC current is used to charge the battery, ultimately achieving battery charging while driving.

[0053] In this embodiment of the application, for step 101, the required torque represents the torque value required by the vehicle. The required torque can be obtained by the vehicle controller, which can determine the torque value by detecting the degree of pedal depressing.

[0054] In this embodiment of the application, for step 101, the battery self-heating requirement refers to the temperature value required to heat the battery, wherein the temperature can be determined according to the user's power response requirements and the ambient temperature.

[0055] In this embodiment of the application, for step 101, the motor current is used as the operating current of the vehicle motor, wherein making the vehicle motor operate under this motor current enables the motor to heat the battery while driving.

[0056] In this embodiment of the application, for step 101, the DC component of the motor current refers to the DC current in the motor current.

[0057] In this embodiment of the application, for step 102, the high frequency in the high frequency current component can generally refer to the range of 1kHz to 5kHz. Of course, this frequency range is just an example and can be determined according to the actual use case.

[0058] In this embodiment of the application, for step 102, the AC current component refers to the AC component in the motor current.

[0059] In this embodiment of the application, for step 104, the motor current can be controlled by a motor controller. For example, the motor controller generates the motor current by outputting voltage to the motor. The voltage output by the motor controller to the motor includes a DC voltage vector in the DQ coordinate system and a high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system.

[0060] In the embodiments of this application, the DQ coordinate system, also known as the dq coordinate system or rotating coordinate system, is a special two-dimensional coordinate system. The DQ coordinate system typically has two axes: the d-axis and the q-axis. These two axes are orthogonal, meaning they are perpendicular to each other. A characteristic of the DQ coordinate system is that it can rotate along with a reference frame, such as the rotor of a motor; therefore, it is also called a rotating coordinate system.

[0061] The principle of this application embodiment is as follows:

[0062] See Figure 2 , Figure 2 This is a schematic diagram of the DC-side current relationship under driving conditions disclosed in an embodiment of this application. Based on Figure 2 For ease of analysis, the internal resistance of the motor windings is omitted. The dynamic relationship equations of voltage (Ud, Uq), electromagnetic torque Te, winding energy storage E, and current of the permanent magnet synchronous motor are as follows:

[0063] ……………………………Equation 1;

[0064] ……………………………Equation 2;

[0065] Equation 3

[0066] Equation 4;

[0067] Furthermore, by superimposing the AC current component (Equation 4) on the DC component of the DQ axis, the energy storage fluctuation power of the motor winding can be calculated as follows:

[0068] ...Equation 5;

[0069] Assume I d,AC I q,AC The fundamental wave frequency of the two AC components is f h Then we can obtain:

[0070] ………………………Equation 6

[0071] Where E1' is the derivative of the alternating current component (fundamental frequency f). h The fundamental oscillation frequency is naturally f, which is the product of the DC component and the DC component. h , and I d,AC I q,AC The fundamental frequency is the same; E2' is the product of the AC component and its own derivative, and its fundamental wave frequency is 2f. h , is I d,AC I q,AC Twice the fundamental frequency. Based on this, it can be seen that the energy stored in the motor windings fluctuated at this time.

[0072] Similarly, by superimposing the AC current component on the DC component of the DQ axis, the motor output torque can be calculated as follows:

[0073] …Formula 7;

[0074] ..8

[0075] Where T e,DC It is the DC component of the torque, T e,AC It is the AC component of torque. , They are The mean and fluctuation portions of this multiplicative term.

[0076] Based on the above calculation formula, it can be seen that the motor output torque also has AC fluctuations at this time; by adjusting Id,DC and Iq,DC, the average output torque of the motor can be controlled.

[0077] Therefore, according to the law of conservation of energy, the power on the DC side of the three-phase inverter bridge = the change in energy stored in the motor + the mechanical energy output by the motor, that is:

[0078] …Form 9;

[0079] Based on the conversion relationship between power and current, we can obtain:

[0080] ...Formula 10

[0081] See Figure 3 , Figure 3 This is a schematic diagram of the DQ-axis current trajectory after superimposed AC components, as disclosed in an embodiment of this application. Figure 3 In the DQ coordinate system shown, the constant winding energy storage lines (solid lines) and constant torque lines (dashed lines) are drawn. When the AC component is superimposed on the DQ axis current, the trajectory of the current in the DQ coordinate system will resemble a Lissajous figure, as shown below. Figure 3 The diagram shows an elliptical trajectory (this is for illustrative purposes only; the actual shape could be any other closed curve). As can be seen, the winding energy storage and output torque differ at different points on the current trajectory. With the periodic oscillation of the current, the winding energy storage and motor output torque also oscillate periodically, thus creating an oscillating current on the DC side of the inverter. The average torque on the current trajectory is the torque that the motor can currently output, and therefore does not affect the actual vehicle torque output.

[0082] In summary, by superimposing an AC component into the DQ axis current, an AC current can be generated on the DC side of the inverter. This AC current originates partly from fluctuations in the energy stored in the motor windings and partly from fluctuations in the output torque. Clearly, this AC current can be used to heat the battery, thereby enabling battery heating during vehicle operation.

[0083] In an optional implementation, the DC component includes a D-axis DC component and a Q-axis DC component, and the high-frequency AC component includes a D-axis AC component and a Q-axis AC component, wherein the D-axis AC component is superimposed on the D-axis DC component, and the Q-axis AC component is superimposed on the Q-axis DC component.

[0084] In the above optional implementation, the expression for superimposing the high-frequency AC component and the DC component is:

[0085] ;

[0086] ;

[0087] in, Represents the D-axis current. Represents the DC component of the D-axis. This represents the AC component of the D-axis, while Represents the Q-axis current. Represents the DC component of the Q-axis. This represents the Q-axis AC component.

[0088] As is known, the high-frequency AC component includes the D-axis AC component and the Q-axis AC component. The D-axis AC component is superimposed with the D-axis DC component, and the Q-axis AC component is superimposed with the Q-axis DC component.

[0089] In one optional implementation of this application, the torque generated by the DC component is equal to the required torque, thus the torque requirement can be met by the DC component.

[0090] In this embodiment of the application, as an optional implementation, the DC component of the motor current is calculated based on the required torque and the battery self-heating requirement, including the following sub-steps:

[0091] The pre-selected current operating point is determined based on the required torque and battery self-heating requirements in the maximum torque-current ratio line.

[0092] Determine the isotorque curve at the pre-selected current operating point;

[0093] Determine the weakening current point or the magnetizing current point based on the equitor lines of the pre-selected current operating point;

[0094] Select the current operating point whose current amplitude meets the preset conditions from either the weakening current point or the strengthening current point as the DC component of the motor current.

[0095] Regarding the above-mentioned optional implementation methods, in order to achieve the goal of heating the battery as quickly as possible, I Inv,AC The higher the better. Since the vehicle operates at relatively low speeds for most of its lifespan, the fluctuating current caused by output torque fluctuations is not significant and can generally be ignored. For a typical electric vehicle "battery-inverter-motor" system, the Ig that the system can obtain is... d,DC Or I q,DC Generally significantly greater than I d,AC Or I q,AC Therefore, fluctuations in DC current are mainly caused by changes in the energy stored in the windings, that is:

[0096] ...Formula 11

[0097] As can be seen from Equation 11, we should maximize I. d,DC I q,DC The absolute value of I is beneficial for increasing the amplitude of alternating current. d,DC I q,DC The requirements for normal torque output also need to be considered. Generally, at low speeds, the motor current operates at the MTPA (Max Torque per Amper) line. To increase I while maintaining constant torque... d,DC I q,DC To obtain the absolute value, the operating point needs to be deviated from the MTPA line and moved along the isotorque line, where the isotorque line is as follows: Figure 4 As shown, Figure 4 This is a schematic diagram of an isotorque line disclosed in an embodiment of this application.

[0098] Furthermore, in Figure 4 If to I d Moving in the direction of increase indicates the magnetization operating point. If moving towards I... d Moving in the direction of decreasing magnetic field strength leads to the magnetic weakening operating point. It is preferable to move in the direction of magnetic weakening because this results in a smaller DC voltage ratio required to sustain the DC component of the current, thus allowing more voltage to be used to generate I. d,AC and I q,AC This further increases I Inv,AC Of course, other considerations may also lead to the selection of a magnetized operating point, such as lower motor harmonic noise at the magnetized operating point.

[0099] As an example, several sets of calculation data are given below. The assumptions made in the calculations are shown in Table 1. Based on these assumptions, the calculation results are plotted in a graph, which includes... Figure 7 , Figure 8 and Figure 9 , Figure 10 In, among them, Figure 7 This is a calculation result diagram of a DC component located on the MTPA line, as disclosed in an embodiment of this application. Figure 8 This is a calculation result diagram for Id=-200A disclosed in an embodiment of this application. Figure 9 This is a calculation result diagram for Id=-400A disclosed in an embodiment of this application. Figure 10 This is a calculation result diagram disclosed in an embodiment of this application when Id=-600A. Figure 7 , Figure 8 and Figure 9 , Figure 10 The left side of the diagram shows the contour map of winding energy storage, the MTPA line, the MTPV line, and different contour lines. The corresponding trajectory of the AC current peak point, optimal The corresponding peak points of the AC current (the points where the stored energy reaches its maximum value Emax and minimum value Emin). In the calculation results graph, the right side shows the voltage limitation graph and the optimal... Vector.

[0100] As can be seen, under typical operating conditions of 5000 rpm, by adjusting the operating current point towards the direction of magnetic field weakening, the AC current can be increased from around 90A to over 400A. A current of 400A is sufficient to quickly heat the battery.

[0101]

[0102] Table 1

[0103] In an optional implementation, the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system is generated by the alternating changes of a first voltage vector and a second voltage vector in the DQ coordinate system. The first voltage vector is located on the maximum available voltage boundary, and the second voltage vector is located within the maximum available voltage boundary. The maximum available voltage boundary is the limit on the voltage output from the inverter to the motor, which is limited by the DC bus voltage. Furthermore:

[0104] U dqL =2U dq0 – U dqH ;

[0105] U dqL U represents the second voltage vector. dqH U represents the first voltage vector. dq0 This is the DC component.

[0106] Regarding the above optional implementation methods, for a given I d,DC and I q,DC In order to increase I Inv,AC Therefore, it is necessary to increase I. d,AC Or I q,AC The rate of change over time, and I d,AC and I q,AC The rate of change is proportional to the magnitude of the applied voltage, that is:

[0107] ...Equation 12

[0108] Corresponding to the AC and DC components of the DQ-axis current, the DQ-axis voltage also has AC and DC components:

[0109] ...Equation 13;

[0110] Furthermore, such as Figure 5 As shown, (U d U q The magnitude of the voltage vector is limited by the inverter DC bus voltage, in the normalized U d U q In the coordinate system, this is represented by a unit circle (without considering modulation), where, Figure 5 This is a schematic diagram illustrating the possible range of a voltage vector disclosed in an embodiment of this application. Because after applying an alternating voltage, the actual voltage vector will be about (U... d,DC U q,DC ) is symmetrical, therefore after the AC component is superimposed, (U d U q The range of possible voltage vector values ​​is shown in region S1 of the figure.

[0111] Furthermore, in order to maximize (U) d,ACU q,AC The fundamental component of (U) is preferably made so that (U) d,AC U q,AC ) is alternating between two vectors of opposite directions and the same magnitude, at which point (U d U q The voltage vector is manifested as alternating changes between two vectors, one of which (U) dqH At the voltage boundary of the gray area, another U dqL in U dqH Regarding (U) d,DC U q,DC The symmetrical position, that is:

[0112] ...Formula 14

[0113] However, see Figure 6 ,like Figure 6 As shown, It can vary freely along a circular arc, that is... Vector Relative The rotation angle θ can also vary. According to Equation 12, for a given I... d,DC and I q,DC There exists an optimal θ such that I Inv,AC The maximum. In a specific solution, this optimal value can be determined through calibration. It should be noted that, Figure 6 This is a schematic diagram of another possible voltage vector range disclosed in the embodiments of this application.

[0114] In an optional implementation, the method further includes: obtaining, through experimentation or simulation, or by using an approximate simplified mathematical model, the value of U that maximizes the energy storage fluctuation amplitude of the motor winding. dqH .

[0115] In this embodiment of the application, as an optional implementation, the fundamental frequency of the high-frequency current component is equal to 10% to 300% of the resonant frequency of the parallel resonant circuit, wherein the parallel resonant circuit is composed of the inverter DC bus capacitor, the stray inductance between the battery and the inverter, and the battery internal resistance.

[0116] Regarding this optional implementation method, since I inv,AC The dominant frequency component is E1', whose fundamental frequency is the same as the fundamental frequency of the alternating current. Figure 2 Yes, if the fundamental frequency of the alternating current is close to the resonant frequency of the resonant circuit, then I can be made inv,AC Amplified through the resonance of the resonant current.

[0117] Example 2

[0118] Please see Figure 11 , Figure 11 This is a schematic diagram of the structure of a battery self-heating device disclosed in an embodiment of this application, as shown below. Figure 11 As shown, the apparatus in this embodiment includes the following functional modules:

[0119] The first calculation module 201 is used to calculate the DC component of the motor current based on the required torque and the battery self-heating requirement.

[0120] The determination module 202 is used to determine the high-frequency current component, which is an alternating current component.

[0121] The second calculation module 203 is used to superimpose the high-frequency AC component with the DC component so that the motor current carries the high-frequency AC component.

[0122] The control module 204 is used to control the motor to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system.

[0123] The apparatus of this application embodiment, by executing the battery self-heating method of this application embodiment, can calculate the DC component of the motor current and determine the high-frequency current component based on the required torque and battery self-heating requirements. The high-frequency current component is an AC current component. It can then superimpose the high-frequency AC component with the DC component, so that the motor current carries the high-frequency AC component. This allows the motor to be controlled to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system. Compared with the prior art, this application can meet the heating and torque requirements during driving by using the DC component of the motor current, thus keeping the vehicle in a driving state. Simultaneously, the high-frequency AC component of the motor current can cause high-frequency changes in the energy storage of the motor windings and the motor output power, thereby generating high-frequency AC current on the DC bus side of the inverter. This high-frequency AC current is used to charge the battery, ultimately achieving battery charging while driving.

[0124] Example 3

[0125] Please see Figure 12 , Figure 12 This is a schematic diagram of the structure of an electronic device disclosed in an embodiment of this application, such as... Figure 12 As shown, the electronic device in this application embodiment includes:

[0126] Processor 301; and

[0127] The memory 302 is configured to store machine-readable instructions that, when executed by a processor, perform a battery self-heating method as described in any of the foregoing embodiments.

[0128] The electronic device of this application embodiment, by executing the battery self-heating method of this application embodiment, can calculate the DC component of the motor current and determine the high-frequency current component based on the required torque and battery self-heating requirements. The high-frequency current component is an AC current component. Furthermore, it can superimpose the high-frequency AC component with the DC component so that the motor current carries the high-frequency AC component. This allows the motor to be controlled to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system. Compared with the prior art, this application can meet the heating and torque requirements during driving by using the DC component of the motor current, thus keeping the vehicle in a driving state. Simultaneously, the high-frequency AC component of the motor current can cause high-frequency changes in the energy storage of the motor windings and the motor output power, thereby generating high-frequency AC current on the DC bus side of the inverter. This high-frequency AC current is used to charge the battery, ultimately achieving battery charging while driving.

[0129] Example 4

[0130] This application provides a storage medium storing a computer program, which is executed by a processor as a battery self-heating method according to any of the foregoing embodiments.

[0131] The storage medium of this application embodiment, by executing the battery self-heating method of this application embodiment, can calculate the DC component of the motor current and determine the high-frequency current component based on the required torque and battery self-heating requirements. The high-frequency current component is an AC current component. Furthermore, the high-frequency AC component and the DC component can be superimposed so that the motor current carries the high-frequency AC component. This allows the motor to be controlled to heat the battery based on the motor current. The DC component is generated by the DC voltage vector in the DQ coordinate system, and the high-frequency current component is generated by the high-frequency AC voltage superimposed on the DC voltage vector in the DQ coordinate system. Compared with the prior art, this application can meet the heating and torque requirements during driving by using the DC component of the motor current, thus keeping the vehicle in a driving state. Simultaneously, the high-frequency AC component of the motor current can cause high-frequency changes in the energy storage of the motor windings and the motor output power, thereby generating high-frequency AC current on the DC bus side of the inverter. This high-frequency AC current is used to charge the battery, ultimately achieving battery charging while driving.

[0132] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and there may be other division methods in actual implementation. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the coupling or direct coupling or communication connection shown or discussed may be through some communication interface; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0133] Furthermore, the units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0134] Furthermore, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0135] It should be noted that if a function is implemented as a software module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0136] In this document, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, without necessarily requiring or implying any such actual relationship or order between these entities or operations.

[0137] The above are merely embodiments of this application and are not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A battery self-heating method, characterized by, The method comprises: calculating a direct current component of the motor current based on the demand torque and a battery self-heating demand; determining a high-frequency current component, which is an alternating current component; superimposing the high-frequency current component on the direct current component so that the motor current carries the high-frequency current component; controlling the motor to heat the battery based on the motor current, wherein the direct current component is generated by direct voltage vector control in a DQ coordinate system, and the high-frequency current component is generated by high-frequency alternating voltage control in the DQ coordinate system superimposed on the direct voltage vector.

2. The method of claim 1, wherein, The direct current component comprises a D-axis direct current component and a Q-axis direct current component, and the high-frequency current component comprises a D-axis alternating current component and a Q-axis alternating current component, wherein the D-axis alternating current component is superimposed on the D-axis direct current component, and the Q-axis alternating current component is superimposed on the Q-axis direct current component.

3. The method of claim 1, wherein, The torque generated by the direct current component is equal to the demand torque.

4. The method of claim 1, wherein, The calculation of the direct current component of the motor current based on the demand torque and the battery self-heating demand comprises: determining a preselected current operating point in a maximum torque current ratio line based on the demand torque and the battery self-heating demand; determining an equal-torque line of the preselected current operating point; determining a field-weakening current point or a field-enhancing current point based on the equal-torque line of the preselected current operating point; selecting, from the field-weakening current point or the field-enhancing current point, a current operating point with a current amplitude satisfying a preset condition as the direct current component of the motor current.

5. The method of claim 4, wherein, The high-frequency alternating voltage superimposed on the direct voltage vector in the DQ coordinate system is generated by alternately changing a first voltage vector and a second voltage vector in the DQ coordinate system, wherein the first voltage vector is located on a maximum available voltage boundary, the second voltage vector is located within the maximum available voltage boundary, the maximum available voltage boundary is a limit of the voltage output by the inverter to the motor under the limit of the direct bus voltage, and there is: U dqL =2U dq0 –U dqH ; U dqL denotes the second voltage vector, U dqH denotes the first voltage vector, U dq0 is the direct current component.

6. The method of claim 5, wherein, The method further comprises: obtaining the selection of U that makes the energy storage fluctuation amplitude of the motor winding reach a maximum value by experiment, or simulation, or in a way of using an approximate simplified mathematical model dqH .

7. The method of claim 5, wherein, The fundamental frequency of the high-frequency current component is equal to 10% to 300% of the resonance frequency of a parallel resonance circuit, wherein the parallel resonance circuit is composed of an inverter direct bus capacitor, a stray inductance between the battery and the inverter, and a battery internal resistance.

8. A battery self-heating device, characterized by, The device comprises: a first calculation module for calculating a direct current component of the motor current based on the demand torque and a battery self-heating demand; a determination module for determining a high-frequency current component, which is an alternating current component; a second calculation module for superimposing the high-frequency current component on the direct current component so that the motor current carries the high-frequency current component; a control module for controlling the motor to heat the battery based on the motor current, wherein the direct current component is generated by direct voltage vector control in a DQ coordinate system, and the high-frequency current component is generated by high-frequency alternating voltage control in the DQ coordinate system superimposed on the direct voltage vector.

9. An electronic device, comprising: comprise: a processor; and a memory configured to store machine-readable instructions that, when executed by the processor, perform the battery self-heating method as claimed in any one of claims 1 to 7.

10. A storage medium, characterized by The storage medium stores a computer program, and the computer program is executed by the processor to perform the battery self-heating method according to any one of claims 1-7.

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