Noise optimization methods, devices, and electric vehicles for power battery heating

Abstract

This invention provides a method, apparatus, and electric vehicle for noise optimization in power battery heating, relating to the field of electric vehicle technology. The method includes: providing a mapping table including the mapping relationship between various musical notes and / or scales and frequencies; providing music data and obtaining the frequency set corresponding to the music based on the mapping table; receiving a battery heating command and generating d-axis current and q-axis current commands; receiving a frequency command containing the music data and generating a fundamental frequency corresponding to the frequency set of the music data based on the frequency command; outputting a DC bias component through a bias loop and injecting it into the fundamental frequency; outputting an effective DC component through an effective value loop; and generating a high-frequency alternating target d-axis current injected into the motor based on the product of the effective DC component and the fundamental frequency of the injected DC bias component. This generates sound resembling music data during battery heating, solving the problem of high-frequency, sharp, and piercing noise generated during existing power battery heating processes.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle technology, and in particular to a method, apparatus, and electric vehicle for noise optimization of power battery heating. Background Technology

[0002] With the rapid development of new energy vehicles, electric vehicles are increasingly being used. However, in low-temperature environments, the movement of electrolytes in the battery slows down, leading to a decrease in battery charging and discharging performance. Therefore, in low-temperature environments, the battery needs to be heated to maintain its charging and discharging performance. Specifically, the battery cells can be directly heated by applying a high-frequency alternating current to generate Joule heat using the battery's internal resistance. However, current methods typically use a high-frequency constant-frequency alternating current, which directly excites capacitive and inductive components in the vehicle's high-voltage network, generating high-frequency, sharp, and harsh noise that affects usability. Summary of the Invention

[0003] In order to overcome the above-mentioned technical defects, the purpose of this invention is to provide a method, device and electric vehicle for noise optimization of power battery heating, and to solve the problem that the existing process of heating power batteries using high-frequency constant alternating current will generate high-frequency sharp and piercing noise.

[0004] This invention discloses a method for noise optimization in power battery heating, comprising:

[0005] A mapping table is provided, which includes the mapping relationship between each note and / or scale and frequency;

[0006] Provide music data and obtain the frequency set corresponding to the music according to the mapping table;

[0007] Receive a battery heating command, generate a d-axis current command and a q-axis current command, wherein the q-axis current command is used to control the output q-axis current to be zero; obtain the initial d-axis current according to the d-axis current command;

[0008] Receive a frequency instruction containing the music data, and generate a fundamental frequency corresponding to the frequency set of the music data according to the frequency instruction;

[0009] The initial d-axis current is output as a DC bias component through a bias loop and injected into the fundamental frequency.

[0010] The initial d-axis current is output as an effective DC component through an effective value loop;

[0011] The target d-axis current of the injected motor is generated by multiplying the effective DC component with the fundamental frequency of the injected DC bias component, so as to produce sound as expressed in the music data during the battery heating process.

[0012] Preferably, the step of outputting the DC bias component of the initial d-axis current through the bias loop includes:

[0013] A calculation window is obtained based on the frequency command, and the bias value of the initial d-axis current is calculated based on the calculation window;

[0014] Upon receiving a bias command, the PI controller controls the initial d-axis current to a bias value of zero based on the initial d-axis current bias value, thereby obtaining a DC bias component.

[0015] Preferably, the injection of the fundamental frequency includes:

[0016] The DC bias component is superimposed on the amplitude corresponding to a preset frequency in the fundamental wave to form a fundamental wave with injected DC bias component.

[0017] Preferably, the step of outputting the effective DC component of the initial d-axis current through an effective value loop includes:

[0018] The sampling frequency is calculated according to the frequency command, and several sampling periods are generated according to the sampling frequency.

[0019] Calculate the effective value of the initial d-axis current in each sampling period;

[0020] It receives the effective value instruction and generates the effective DC component through the PI controller based on the effective values ​​in each sampling period.

[0021] Preferably, calculating the effective value of the initial d-axis current in each sampling period includes:

[0022] For any sampling period, the squares of the initial d-axis currents corresponding to each sampling point are summed, the square root is taken, and then the average is taken to obtain the effective value of the initial d-axis current.

[0023] Preferably, the calculation window for the bias loop and the sampling frequency of the effective value loop are calculated according to the frequency command;

[0024] The sampling frequency and the calculation window are set to be reciprocals of each other.

[0025] Preferably, it further includes: injecting a tooth-aligning current into the q-axis.

[0026] Preferably, it further includes:

[0027] The loop circuit receives a frequency command containing the music data to generate sound that is represented as the music data during battery heating.

[0028] The present invention also provides a noise optimization device for power battery heating, comprising:

[0029] A preprocessing module is used to provide a mapping table, which includes the mapping relationship between each note and / or scale and frequency; and to provide music data and obtain the frequency set corresponding to the music according to the mapping table.

[0030] The receiving module is used to receive battery heating commands, generate d-axis current commands and q-axis current commands, wherein the q-axis current command is used to control the output q-axis current to have a value of zero; and obtain the initial d-axis current according to the d-axis current command.

[0031] The first processing module is configured to receive a frequency instruction containing the music data, and generate a fundamental frequency corresponding to the frequency set of the music data according to the frequency instruction; and inject the initial d-axis current into the fundamental frequency by outputting a DC bias component through a bias loop.

[0032] The second processing module is used to output the effective DC component of the initial d-axis current through the effective value loop;

[0033] The output module is used to generate a high-frequency alternating target d-axis current for the motor based on the product of the effective DC component and the fundamental frequency of the injected DC bias component, so as to generate noise in the form of the music data during the battery heating process.

[0034] The present invention also provides an electric vehicle, including: a noise optimization device incorporating the aforementioned power battery heating.

[0035] Compared with existing technologies, the above technical solution has the following advantages:

[0036] The basic scale is pre-calibrated to obtain the mapping relationship between each note and / or scale and frequency. Music data is provided in advance to generate the corresponding frequency set. After receiving the heating command, the q-axis current with an output value of zero is controlled. The frequency command containing the music data is received and the fundamental frequency is generated. The bias loop component is output through the bias loop, and the effective DC component is output through the effective value loop. This is used to accurately control the frequency and amplitude of the current based on the fundamental frequency. The high-frequency current is output for battery heating, so that while the high-frequency current is injected to heat the battery, the noise generated is distributed along the frequency variation of the preset music data, producing a sound similar to the music data, avoiding the harsh and sharp noise generated by injecting a constant high-frequency alternating current. Attached Figure Description

[0037] Figure 1 This is a flowchart of an embodiment of the noise optimization method for power battery heating according to the present invention;

[0038] Figure 2 This is a schematic diagram of the control process in Embodiment 1 of the noise optimization method for power battery heating according to the present invention;

[0039] Figure 3 This is a schematic diagram of a module in Embodiment 2 of the noise optimization device for power battery heating according to the present invention.

[0040] Figure label:

[0041] 7-Noise optimization device for power battery heating; 71-Pre-processing module; 72-Receiving module; 73-First processing module; 74-Second processing module; 75-Output module. Detailed Implementation

[0042] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0043] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0044] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0045] It should be understood that although the terms first, second, third, etc., may be used in this disclosure to describe various information, such information should not be limited to these terms. These terms are used only to distinguish information of the same type from one another. For example, without departing from the scope of this disclosure, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Depending on the context, the word "if" as used herein may be interpreted as "when," "when," or "in response to determination."

[0046] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0047] In the description of this invention, unless otherwise specified and limited, it should be noted that the terms "installation", "connection" and "linking" should be interpreted broadly. For example, they can refer to mechanical or electrical connections, or internal connections between two components. They can be direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0048] In the following description, suffixes such as "module," "part," or "unit" used to denote elements are used only for the convenience of the description of the invention and have no specific meaning in themselves. Therefore, "module" and "part" can be used interchangeably.

[0049] Example 1: This example discloses a noise optimization method for power battery heating. It is emphasized that this embodiment optimizes the noise generated during the power battery heating process by representing the noise as a preset musical piece, thereby avoiding the generation of harsh and sharp noise. For details, please refer to... Figure 1 and Figure 2 Including the following:

[0050] S100: Provide a mapping table, the mapping table including the mapping relationship between each note and / or scale and frequency; provide music data, and obtain the frequency set corresponding to the music data according to the mapping table;

[0051] In this embodiment, in order to overcome the high-frequency harsh noise generated during battery heating, the amplitude and frequency of the injected current during battery heating are accurately controlled to control the current that may generate sharp and harsh noise into a sound that can produce a preset melody. Therefore, it is necessary to pre-set the music data corresponding to the generated melody. The music data includes parameters such as notes and scales. According to the above mapping table, the frequency corresponding to the music data can be obtained. That is, the frequency of the current used for battery heating is controlled to be approximately similar to the frequency corresponding to the music data. This makes it so that while injecting high-frequency current to heat the battery, the noise generated is distributed along the frequency variation of the preset music data, producing a sound that approximates the music data, thus avoiding the generation of harsh and sharp noise by injecting a high-frequency constant alternating current.

[0052] Specifically, in the above steps, the mapping table and the frequency set corresponding to the music data are obtained in advance. Specifically, this can be achieved through human ear calibration. The motor is pre-controlled to operate with a suitable effective current command (the motor does not demagnetize during long-term operation, and the injected bus current is large enough). The operating frequency of the motor is adjusted in small steps. The basic scale is calibrated by human ear, that is, the mapping relationship between each note and / or scale and frequency in the above mapping table is obtained. The scale commands, rhythm commands, etc. of the musical score are entered into the software in the form of a lookup table. The selectable musical scores should contain as many scales with large injected current as possible, that is, the above music data and the frequency set corresponding to the music data are generated, so as to control the current amplitude and frequency injected during the battery heating process.

[0053] S200: Receives a battery heating command, generates a d-axis current command and a q-axis current command, wherein the q-axis current command (IqCmd) is used to control the q-axis current with an output value of zero; obtains the initial d-axis current according to the d-axis current command;

[0054] For illustration, in this embodiment, to control the amplitude and frequency of the injected current and transform noise into sound resembling musical data, a command control method is primarily employed, executing feedback after receiving control commands. The initial d-axis current and initial q-axis current can be obtained from the three-phase current controlled by the motor through Clarke and Park transformations. The initial q-axis current is controlled by a PI controller to achieve a zero output value, thus limiting motor rotation and allowing the battery to be heated after high-frequency current is injected into the d-axis. It may also include injecting a tooth-gripping current into the q-axis to increase tooth torque, ensuring a tight meshing between the driving and driven gears, thereby eliminating the influence of backlash, reducing motor mechanical vibration, and improving safety.

[0055] S300: Receive a frequency instruction containing the music data, and generate a fundamental frequency corresponding to the frequency set of the music data according to the frequency instruction;

[0056] In the above steps, in order to achieve the sound that is consistent with the performance of the music data by injecting high-frequency current, rather than high-frequency harsh noise, the frequency and / or amplitude of the injected high-frequency current are consistent with or approximately the same as the frequency set corresponding to the music data. Therefore, a fundamental wave is generated based on the frequency consistent with the music data. This fundamental wave serves as the basis for the subsequent output d-axis voltage and injected d-axis current in this embodiment. Then, a bias loop and an effective value loop are set to process the initial d-axis current and adjust it based on the fundamental wave to achieve precise control of the frequency and amplitude of the current.

[0057] Specifically, it also includes: the loop circuit receives a frequency command containing the music data so that the loop circuit generates sound that is represented as the music data during the battery heating process. The software program can be set to perform a loop circuit lookup table and loop the scale command (i.e. the above frequency command) to the controller to achieve the loop circuit playback effect of the song.

[0058] Following the above steps, the calculation window for the bias loop and the sampling frequency for the RMS loop can be calculated based on the received frequency command; the sampling frequency and the calculation window are set to be reciprocals of each other. That is, for the bias loop and the RMS loop described below, as an example to illustrate that the operation of the RMS loop and the bias loop needs to be properly synchronized, if the above time window is set to 100Hz, then the sampling frequency is set to 10ms, which ensures that the operation of the RMS loop and the above bias loop corresponds, so as to accurately and quantitatively control the frequency and amplitude of the current.

[0059] S400: The initial d-axis current is output as a DC bias component through the bias loop and injected into the fundamental frequency;

[0060] In the above steps, the bias loop calculates and adjusts the initial d-axis current bias, which is the degree of deviation of the formed periodic sine wave from the preset axis. The introduction of the bias loop makes the control more stable. Specifically, the step of outputting the DC bias component of the initial d-axis current through the bias loop includes:

[0061] A calculation window is obtained based on the frequency command, and the bias value of the initial d-axis current is calculated based on the calculation window. A bias command (OffsCmd) is received, and the initial d-axis current is controlled by a PI controller to have an output bias of zero based on the initial d-axis current bias value, thus obtaining a DC bias component. That is, the initial d-axis current has a certain bias, and after being controlled by the PI controller based on the bias command, the output bias is zero, i.e., a DC bias component is applied, thereby eliminating the existing bias. This DC bias component is the output from the above steps.

[0062] Specifically, injecting the fundamental wave in the above steps includes: superimposing the DC bias component onto the amplitude corresponding to a preset frequency in the fundamental wave to form a fundamental wave with injected DC bias component. In this embodiment, the injected fundamental wave is injected by superimposing the DC bias component onto a preset frequency of each cycle of the fundamental wave, rather than superimposing it as a whole. For example, one cycle of the fundamental wave can be set to 1000Hz and 3000μs, and the operating frequency of the bias loop obtained according to the time window can be 100Hz and 300μs. This can divide each cycle of the carrier into 10 beats. The DC bias component is preset to be superimposed onto the amplitude corresponding to the carrier in the first 3 beats of each cycle, so that the stability of the overall amplitude change of the carrier is increased. That is, the DC output of the bias loop is injected into the first n beats of each cycle of the carrier in the form of harmonics, and precise frequency control can be achieved without additional energy storage components.

[0063] S500: Output the effective DC component of the initial d-axis current through the effective value loop;

[0064] In the above steps, the RMS loop can be used to precisely control the current amplitude in real time, enabling flexible and quantitative injection current amplitude control. The step of outputting the effective DC component of the initial d-axis current through the RMS loop includes:

[0065] S510: Calculate the sampling frequency according to the frequency command, and generate several sampling periods according to the sampling frequency;

[0066] In the above steps, as mentioned above, the operation of the RMS loop and the bias loop needs to be properly synchronized in order to perform accurate quantitative control. Therefore, the sampling frequency can be directly obtained according to the frequency command.

[0067] S520: Calculate the effective value of the initial d-axis current in each sampling period;

[0068] Specifically, calculating the effective value of the initial d-axis current in each sampling period includes: for any sampling period, summing the squares of the initial d-axis currents corresponding to each sampling point, taking the square root, and then averaging them to obtain the effective value of the initial d-axis current.

[0069] For illustration, the following formula can be used to calculate the effective value: Where N represents the sampling points within the sampling period, i d The initial d-axis current value corresponds to each sampling point.

[0070] S530: Receives the effective value instruction (RmsCmd) and generates the effective DC component through the PI controller based on the effective value in each sampling period.

[0071] In the above steps, the system receives commands, uses PI control feedback, and controls the system based on the difference between the command and the feedback to generate an effective DC component. It also calculates the effective value of the feedback current in real time and uses this value for effective value loop control.

[0072] As a supplement, in order to ensure that the operation of the bias loop and the RMS loop does not interfere with each other, the bandwidth of the bias loop is set to be lower than the bandwidth of the RMS loop, so that the frequency range occupied by the various frequency components contained in the bias loop and the RMS loop are different. Specifically, the bandwidth of the bias loop is much lower than that of the RMS loop.

[0073] S600: Generate a high-frequency alternating target d-axis current for the motor based on the product of the effective DC component and the fundamental frequency of the injected DC bias component, so as to generate sound as the music data during the battery heating process.

[0074] In the above steps, the DC Ud component controlled by the effective value loop is multiplied with the carrier wave to obtain the AC Ud. Then, the α and β axis voltages are obtained through inverse Park transformation, and then input to the SVM control to inject the high-frequency alternating target d-axis voltage into the motor to execute the battery heating process. At the same time, it generates music data sound instead of harsh and sharp noise. In this embodiment, no additional energy storage components are required, and the BSW is not needed to optimize noise. Specifically, the unacceptable noise (harsh and piercing) is transformed into pleasant music (based on the provided music data), and multiple songs can be stored for selective playback. By setting up a bias loop and an effective loop, NVH is optimized while taking into account the injection of a large bus current. The introduction of the bias loop reduces abnormal motor rotation during the heating process and allows for real-time monitoring of key information such as motor speed, heating current, and motor temperature to further improve safety.

[0075] Example 2: This example provides a noise optimization device 7 for power battery heating, see reference. Figure 3 ,include:

[0076] The preprocessing module 71 is used to provide a mapping table, which includes the mapping relationship between each note and / or scale and frequency; and to provide music data and obtain the frequency set corresponding to the music according to the mapping table.

[0077] In the above steps, the mapping table and the frequency set corresponding to the music data are obtained in advance. Specifically, this can be achieved through human ear calibration. The motor is pre-controlled to operate with a suitable effective current command (the motor does not demagnetize during long-term operation, and the injected bus current is large enough). The operating frequency of the motor is adjusted in small steps. The basic scale is calibrated by human ear, thus obtaining the mapping relationship between each note and / or scale and frequency in the above mapping table. The scale commands and beat commands of the musical score are entered into the software in the form of a lookup table. The selectable musical scores should contain as many scales as possible with large injected current, thus generating the above music data (multiple music data can be set, or a music data set can contain multiple musical scores) and the frequency set corresponding to the music data. This allows for subsequent control of the current amplitude and frequency injected during battery heating, so that while injecting high-frequency current to heat the battery, the noise generated is distributed along the frequency variation of the preset music data, producing a sound similar to the music data, avoiding the generation of harsh and sharp noise by injecting high-frequency constant alternating current.

[0078] Receiver module 72 is used to receive battery heating commands, generate d-axis current commands and q-axis current commands, wherein the q-axis current command is used to control the output q-axis current to be zero; and to obtain the initial d-axis current according to the d-axis current command.

[0079] Specifically, controlling the q-axis current output to zero limits motor rotation. Additionally, injecting tooth-aligning current into the q-axis eliminates the influence of tooth backlash, reduces motor mechanical vibration, and improves safety.

[0080] The first processing module 73 is used to receive a frequency instruction containing the music data, and generate a fundamental wave whose frequency corresponds to the frequency set of the music data according to the frequency instruction; and to output a DC bias component of the initial d-axis current through a bias loop and inject it into the fundamental wave.

[0081] Specifically, in this module, the bias loop controls the initial d-axis current to a bias value of zero based on the bias value of the initial d-axis current through a PI controller, outputting a DC bias component. This DC bias component is superimposed on the preset frequency of each cycle of the fundamental wave to achieve precise control of the injected current frequency, making it consistent with the frequency of the music data. Thus, the sound that appears as music data is generated during the battery heating process, rather than a sharp and piercing noise.

[0082] The second processing module 74 is used to output the effective DC component of the initial d-axis current through the effective value loop;

[0083] Specifically, in this module, the effective value loop precisely controls the amplitude of the current, enabling flexible and quantitative control of the injected current amplitude. After calculating the effective value of the current according to the formula described in Example 1, the effective DC component of the output is controlled.

[0084] Output module 75 is used to generate a high-frequency alternating target d-axis current based on the product of the effective DC component and the fundamental frequency of the injected DC bias component, so as to generate noise in the form of the music data during the battery heating process.

[0085] Specifically, a fundamental frequency is generated based on the frequency consistent with the music data. A bias loop and an effective value loop are set to process the initial d-axis current and adjust it based on the fundamental frequency to achieve precise control of the current frequency and amplitude, producing sound that manifests as music data during the battery heating process.

[0086] In this embodiment, the preprocessing module pre-calibrates the basic musical scale by human ear to obtain the mapping relationship between each note and / or scale and frequency in the above mapping table, and provides music data in advance to generate the corresponding frequency set. When the receiving module receives the heating command, it controls the output value of the q-axis current to zero to limit the rotation of the motor. Then, it receives the frequency command containing the music data and generates the fundamental wave. The bias loop of the first processing module outputs the bias loop component of the initial d-axis current based on the frequency command, and at the same time outputs the effective DC component through the effective value loop to accurately control the frequency and amplitude of the current. The output module adjusts the output based on the fundamental wave to output a high-frequency current for battery heating, and generates sound that manifests as music data during the battery heating process.

[0087] Example 3: This example provides an electric vehicle, including: applying the noise optimization device for power battery heating as described in Example 2 to implement the power battery heating noise optimization method of Example 1. The electric vehicle also includes other components and control devices for operation, which will not be described in detail here. It is used to solve the problem that the existing process of heating the power battery with a high-frequency constant alternating current will generate high-frequency sharp and piercing noise. The electric vehicle using this device generates sound in the form of music data during the heating process to replace the sharp and piercing noise.

[0088] It should be noted that the embodiments of the present invention have better implementability and are not intended to limit the present invention in any way. Any person skilled in the art may use the above-disclosed technical content to change or modify it into equivalent effective embodiments. However, any modifications or equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A method for optimizing the noise of power battery heating, characterized in that, include: A mapping table is provided, which includes the mapping relationship between each note and / or scale and frequency; Provide music data and obtain the frequency set corresponding to the music according to the mapping table; Receive a battery heating command, generate a d-axis current command and a q-axis current command, wherein the q-axis current command is used to control the output q-axis current to be zero; obtain the initial d-axis current according to the d-axis current command; Receive a frequency instruction containing the music data, and generate a fundamental frequency corresponding to the frequency set of the music data according to the frequency instruction; The initial d-axis current is output as a DC bias component through a bias loop and injected into the fundamental frequency. The initial d-axis current is output as an effective DC component through the effective value loop, and the bandwidth of the bias loop is set to be lower than that of the effective value loop, so that the frequency ranges occupied by the various frequency components contained in the bias loop and the effective value loop are different. The target d-axis current, which is a high-frequency alternating current injected into the motor, is generated based on the product of the effective DC component and the fundamental frequency of the injected DC bias component, so as to produce sound, which is represented by the music data, during the battery heating process; in The step of outputting the DC bias component of the initial d-axis current through the bias loop includes: A calculation window is obtained based on the frequency command, and the bias value of the initial d-axis current is calculated based on the calculation window; Upon receiving a bias command, the PI controller controls the initial d-axis current to a bias of zero based on the initial d-axis current bias value, thereby obtaining the DC bias component. The calculation window for the bias loop and the sampling frequency of the effective value loop are calculated based on the frequency command. The sampling frequency and the calculation window are set to be reciprocals of each other.

2. The noise optimization method according to claim 1, characterized in that, The injection of the fundamental wave includes: The DC bias component is superimposed on the amplitude corresponding to a preset frequency in the fundamental wave to form a fundamental wave with injected DC bias component.

3. The noise optimization method according to claim 1, characterized in that, The step of outputting the effective DC component of the initial d-axis current through an effective value loop includes: The sampling frequency is calculated according to the frequency command, and several sampling periods are generated according to the sampling frequency. Calculate the effective value of the initial d-axis current in each sampling period; It receives the effective value instruction and generates the effective DC component through the PI controller based on the effective values ​​in each sampling period.

4. The noise optimization method according to claim 3, characterized in that, The calculation of the effective value of the initial d-axis current in each sampling period includes: For any sampling period, the squares of the initial d-axis currents corresponding to each sampling point are summed, the square root is taken, and then the average is taken to obtain the effective value of the initial d-axis current.

5. The noise optimization method according to claim 1, characterized in that, Also includes: Inject tooth-aligned current into the q-axis.

6. The noise optimization method according to claim 1, characterized in that, Also includes: The loop circuit receives a frequency command containing the music data to generate sound that is represented as the music data during battery heating.

7. A noise optimization device for power battery heating, characterized in that, include: A preprocessing module is used to provide a mapping table, which includes the mapping relationship between each note and / or scale and frequency; Provide music data and obtain the frequency set corresponding to the music according to the mapping table; The receiving module is used to receive battery heating commands, generate d-axis current commands and q-axis current commands, wherein the q-axis current command is used to control the output q-axis current to have a value of zero; and obtain the initial d-axis current according to the d-axis current command. The first processing module is configured to receive a frequency instruction containing the music data, and generate a fundamental frequency corresponding to the frequency set of the music data according to the frequency instruction; and inject the initial d-axis current into the fundamental frequency by outputting a DC bias component through a bias loop. The second processing module is used to output the effective DC component of the initial d-axis current through the effective value loop, and to set the bandwidth of the bias loop to be lower than the bandwidth of the effective value loop, so that the frequency range occupied by the various frequency components contained in the bias loop and the effective value loop are different. The output module is used to generate a high-frequency alternating target d-axis current for the motor based on the product of the effective DC component and the fundamental frequency of the injected DC bias component, so as to generate sound as the music data during the battery heating process. in The step of outputting the DC bias component of the initial d-axis current through the bias loop includes: A calculation window is obtained based on the frequency command, and the bias value of the initial d-axis current is calculated based on the calculation window; Upon receiving a bias command, the PI controller controls the initial d-axis current to a bias of zero based on the initial d-axis current bias value, thereby obtaining the DC bias component. The calculation window for the bias loop and the sampling frequency of the effective value loop are calculated based on the frequency command. The sampling frequency and the calculation window are set to be reciprocals of each other.

8. An electric vehicle, characterized in that, include: The application includes the noise optimization device for power battery heating as described in claim 7.

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