Noise processing method and device for power battery heating and electric vehicle

Abstract

The application provides a power battery heating noise processing method and device and an electric vehicle, and relates to the field of noise control.The application comprises the following steps: receiving a power battery heating instruction, and generating a d-axis current instruction and a q-axis current instruction according to the power battery heating instruction; outputting a q-axis voltage through a PI controller according to the q-axis current instruction, so as to control the q-axis current with an output value of zero; controlling a d-axis voltage to be output through hysteresis control according to the d-axis current instruction; generating a random factor at a preset frequency, adjusting the amplitude of the d-axis voltage according to the random factor, randomly adjusting the current slope of the motor at each pulse current point, generating a random pulse current acting on the power battery, and making the noise generated in the battery heating process randomly distributed, so as to solve the problem that the existing power battery heating process using high-frequency constant-frequency alternating current generates high-frequency sharp and piercing noise.

Description

Technical Field

[0001] This invention relates to the field of noise control, and more particularly to a noise treatment method, apparatus, and electric vehicle for heating a power battery. 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, high-frequency alternating current can be applied using the battery's internal resistance to generate Joule heat, directly heating the battery cells to improve the uneven heating and low efficiency issues associated with external PTC heating systems. However, this high-frequency, constant-frequency alternating current 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 noise treatment method, device and electric vehicle for heating power batteries, and to solve the problem that high-frequency sharp and piercing noise is generated in the existing process of heating power batteries using high-frequency constant frequency alternating current.

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

[0005] Receives a power battery heating command and generates a d-axis current command and a q-axis current command based on the power battery heating command;

[0006] According to the q-axis current command, the PI controller outputs the q-axis voltage to control the q-axis current with an output value of zero;

[0007] The d-axis voltage is output via hysteresis control based on the d-axis current command.

[0008] A random factor is generated at a preset frequency, and the amplitude of the d-axis voltage is adjusted according to the random factor to randomly adjust the current slope of the motor at each pulse current point, thereby generating a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed.

[0009] Preferably, the random factor is set to a random number in the range of 0.2-1 generated according to a preset random function.

[0010] Preferably, adjusting the amplitude of the d-axis voltage according to the random factor includes:

[0011] The real-time amplitude of the d-axis voltage is obtained, and the amplitude of the d-axis voltage is adjusted by multiplying the real-time amplitude by the random factor.

[0012] Preferably, adjusting the amplitude of the d-axis voltage according to the random factor to randomly adjust the current slope of the motor at each pulse current point and generate a random pulse current acting on the power battery includes:

[0013] The positive relationship between the d-axis voltage and q-axis voltage and the slopes of the d-axis current and q-axis current, respectively, is determined based on the motor voltage equation.

[0014] Based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate a random pulse current acting on the power battery.

[0015] Preferably, the q-axis current with a control output value of zero further includes:

[0016] Injecting a tooth-like current into the q-axis suppresses the mechanical vibration of the motor.

[0017] The present invention also provides a noise reduction device for heating a power battery, comprising:

[0018] The receiving module is used to receive the power battery heating command and generate d-axis current command and q-axis current command according to the power battery heating command;

[0019] The first processing module is used to output the q-axis voltage through the PI controller according to the q-axis current command, so as to control the q-axis current with an output value of zero.

[0020] The second processing module is used to output the d-axis voltage through hysteresis control according to the d-axis current command.

[0021] The adjustment module is used to generate a random factor at a preset frequency, adjust the amplitude of the d-axis voltage according to the random factor, and randomly adjust the current slope of the motor at each pulse current point to generate a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed.

[0022] The present invention also provides a battery heating system that utilizes the above-described noise reduction device for power battery heating.

[0023] Compared with existing technologies, the above technical solution has the following advantages:

[0024] In this embodiment, a random factor is generated by a random function, and the amplitude of the injected d-axis voltage is adjusted to indirectly change the frequency of the injected current. By randomizing the injected pulse current, the energy of the noise is randomly distributed, thus solving the problem that high-frequency sharp and piercing noise is generated in the existing process of heating the power battery with high-frequency constant-frequency AC current. Attached Figure Description

[0025] Figure 1 This is a flowchart of an embodiment of the noise reduction method for heating a power battery according to the present invention;

[0026] Figure 2 This is a schematic diagram of the circuit flow in Embodiment 1 of the noise reduction method for heating the power battery according to the present invention;

[0027] Figure 3 This is a reference diagram of the phase current in Embodiment 1 of the noise reduction method for heating the power battery according to the present invention;

[0028] Figure 4 This is a reference diagram of the noise in Embodiment 1 of the noise treatment method for heating the power battery according to the present invention;

[0029] Figure 5 This is a schematic diagram of a module in Embodiment 2 of the noise reduction device for power battery heating according to the present invention.

[0030] Figure label:

[0031] 5-Noise reduction device for power battery heating; 51-Receiving module; 52-First processing module; 53-Second processing module; 54-Adjustment module. Detailed Implementation

[0032] The advantages of the present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments.

[0033] 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.

[0034] 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.

[0035] 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."

[0036] 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.

[0037] 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.

[0038] 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.

[0039] Example: This example discloses a noise reduction method for heating a power battery, which solves the problem of high-frequency, sharp, and piercing noise generated during the existing process of heating a power battery using a high-frequency constant-frequency alternating current. For details, refer to... Figures 1-2 ,include:

[0040] S100: Receives a power battery heating command and generates a d-axis current command and a q-axis current command based on the power battery heating command;

[0041] In this embodiment, it is mainly used to solve the problem of noise generated during the heating process of the power battery. Therefore, it needs to be triggered according to the power battery heating command. It should be noted that during the power battery heating process, the d-axis current command is used to generate a high-frequency constant frequency AC current, and the q-axis current command needs to generate a q-axis current with a value of zero to limit the torque output, that is, to avoid the situation where applying the q-axis current directly causes the motor to rotate.

[0042] S200: Based on the q-axis current command (IqCmd), the PI controller outputs the q-axis voltage to control the q-axis current with an output value of zero;

[0043] In this embodiment, after the heating command is given, the bus voltage is applied. The three-phase current output from the bus voltage is converted into d-axis current and q-axis current by Clark transformation. As mentioned above, in order to avoid the motor from rotating, the q-axis current with a control output value of zero is directly implemented by the PI controller.

[0044] In this embodiment, to further improve safety during the power battery heating process, the q-axis current with a control output value of zero further includes injecting a tooth-aligning current into the q-axis to suppress the mechanical vibration of the motor. Addressing the tooth backlash in various transmission components of electric vehicles, which causes tooth knocking (the driving gear colliding with the driven gear) during vehicle start-up and acceleration / deceleration, a tooth-aligning torque can be applied to ensure that the driving and driven gears are always tightly meshed, thus eliminating the impact of tooth backlash. Therefore, this solution also injects a tooth-aligning current to generate a tooth-aligning torque, further preventing the motor from rotating.

[0045] S300: Controls the output of d-axis voltage via hysteresis control according to the d-axis current command;

[0046] In the above implementation, after obtaining the d-axis current following the Clark transformation, hysteresis control is performed. Hysteresis control is also known as bang-bang control or ripple regulator control. Figure 2 ThrsP and ThrsN at the top center are random factor generation instructions. Figure 2 The ThrsP and ThrsN instructions at the bottom center (which are hysteresis control generation instructions) connect the output of the switching function calculation module to the hysteresis comparator to generate control pulses. Specifically, this control can include autonomously adjusting the direction of the d-axis voltage. Specifically, a maximum threshold and a minimum threshold are set, and when the d-axis current exceeds the maximum or minimum threshold, the direction is automatically changed to improve output efficiency. The d-axis current is hysteresis controlled, which has a small computational load and is simple to control.

[0047] S400: Generate a random factor at a preset frequency, adjust the amplitude of the d-axis voltage according to the random factor, randomly adjust the current slope of the motor at each pulse current point, generate a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed.

[0048] In this embodiment, the purpose is to adjust the d-axis voltage and thus the noise distribution to reduce sharp and harsh noise. Therefore, the relationship between the d-axis voltage and noise generation is first determined. Specifically, the amplitude of the d-axis voltage is adjusted according to the random factor to randomly adjust the current slope of the motor at each pulse current point and generate a random pulse current acting on the power battery. This includes determining the positive change relationship between the d-axis voltage and q-axis voltage and the d-axis current slope and q-axis current slope, respectively, according to the motor voltage equation.

[0049] Specifically, for illustration, the voltage equation is as follows:

[0050]

[0051] Among them, u d u q These are the d-axis voltage and q-axis voltage, respectively, R s For phase resistance; i d i q ω represents the d-axis current and q-axis current; ω represents the motor speed; L d L q These are the d-axis inductance and q-axis inductance, respectively; ψ f It is a magnetic flux.

[0052] Based on the above voltage equation, the motor speed is 0 during the heating process of the power battery, the motor is stationary, the back electromotive force introduced by the rotation can be ignored, the phase resistance of the motor is low, and the voltage drop of the phase resistance can be ignored. Therefore, the following equations (1) and (2) can be obtained:

[0053]

[0054] in, The slopes of the d-axis current and the q-axis current are respectively. According to equation (2), when the motor is at a certain pulse current point, the current rise or fall slope of the next pulse is determined by the magnitude of the current injected voltage. This law can be used to change the frequency of the injected pulse current. Therefore, based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate a random pulse current acting on the power battery.

[0055] In the above steps, the slope of the generated d-axis current can be changed according to the amplitude of the d-axis voltage. Since the q-axis current is zero, the frequency of the injected pulse current can be changed by altering the d-axis current. In this embodiment, a random factor is set to adjust the amplitude of the d-axis voltage, thereby adjusting the current slope and consequently adjusting the peak value and sound pressure level of the generated near-field noise, thus processing the noise and solving the problem of generating sharp, piercing noise.

[0056] It should be noted that the random factor is set to a random number in the range of 0.2-1 generated by a preset random function. Specifically, as an example, the preset random function can be set to include, but is not limited to, the random() function, srand(), etc., to set the upper and lower limits of the generated random number, that is, a random number in the range of 0.2-1, so as to adjust the amplitude of the d-axis voltage.

[0057] Specifically, adjusting the amplitude of the d-axis voltage according to the random factor includes: obtaining the real-time amplitude of the d-axis voltage, and adjusting the amplitude of the d-axis voltage by multiplying the real-time amplitude by the random factor. In this embodiment, the adjustment of the d-axis voltage amplitude by the random factor is achieved through direct multiplication of the two, which is simple and efficient. It should be noted that the random number switching at a predetermined frequency can be consistent with or inconsistent with the frequency of the d-axis current. For example, the random factor sampling frequency is set to 10ms; the current frequency sampling frequency is 100μs.

[0058] To further illustrate the role of the random factor in this embodiment, please refer to... Figure 3 As a reference diagram for phase current, after randomizing the d-axis voltage injection, the phase current response frequency is also randomized; reference Figure 4 The waveform diagram of the incoming noise shows that, using the noise processing method of this embodiment, the peak value and sound pressure level of the near-field noise are significantly reduced. The original noise peak value is relatively high and sharp, and the processed noise exhibits obvious random fluctuations, thereby achieving the processing of sharp noise.

[0059] In the above steps, the q-axis voltage and the adjusted d-axis voltage are used to obtain the α-axis voltage and β-axis voltage through inverse Park transformation, and then input into the SVM to control the execution of the battery heating process. In this embodiment, based on the above-mentioned generation of random factors through a random function, the upper and lower limits of the random factors can be calibrated, the generation frequency of the random factors can be preset, no additional components are required, and no BSW is needed. The battery heating process is controlled by adjusting the injected U... d The amplitude indirectly changes the frequency of the injected current; by randomly injecting the pulse current, the energy of noise is randomly distributed, improving NVH performance. It can also monitor key information such as motor speed, heating current, and motor temperature in real time to further enhance safety.

[0060] Example 2: The present invention also provides a noise reduction device 5 for heating a power battery, see reference. Figure 5 ,include:

[0061] The receiving module 51 is used to receive the power battery heating command and generate the d-axis current command and the q-axis current command according to the power battery heating command;

[0062] Specifically, during the power battery heating process, the d-axis current command is used to generate a high-frequency constant-frequency alternating current to achieve battery heating, while the q-axis current command needs to generate a q-axis current with a value of zero to limit the motor rotation.

[0063] The first processing module 52 is used to output the q-axis voltage through the PI controller according to the q-axis current command, so as to control the q-axis current with an output value of zero.

[0064] Specifically, by outputting the q-axis current through the PI controller, a tooth-aligning current can also be injected into the q-axis to further suppress the mechanical vibration of the motor and increase safety during the battery heating process.

[0065] The second processing module 53 is used to control the output of d-axis voltage through hysteresis control according to the d-axis current command.

[0066] Specifically, hysteresis control is performed on the d-axis current obtained after the three-phase current transformation, which involves little calculation and is simple to control.

[0067] The adjustment module 54 is used to generate a random factor at a preset frequency, adjust the amplitude of the d-axis voltage according to the random factor, and randomly adjust the current slope of the motor at each pulse current point to generate a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed.

[0068] Specifically, the positive relationship between the d-axis voltage and q-axis voltage and the d-axis current slope and q-axis current slope, respectively, is determined according to the motor voltage equation. Based on the q-axis voltage and the adjusted d-axis voltage obtained using random factors, the current slope of the motor at each pulse current point is randomly adjusted to generate random pulse currents acting on the power battery. The upper and lower limits of the random factors and the generation frequency can be preset without additional components. The frequency of the injected current is indirectly changed by adjusting the amplitude of the injected d-axis voltage. By randomizing the injected pulse current, the energy of noise is randomly distributed, thereby improving NVH performance.

[0069] Example 3: The present invention also provides an electric vehicle that utilizes the noise reduction device for power battery heating described in Example 2. It may also include other electronic components for the operation of the electric vehicle. By randomly injecting pulse current, the noise energy is randomly distributed, improving NVH performance and solving the problem of high-frequency, sharp, and harsh noise generated during the existing process of heating the power battery using high-frequency constant-frequency alternating current.

[0070] 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 noise reduction in power battery heating, characterized in that, include: Receives a power battery heating command and generates a d-axis current command and a q-axis current command based on the power battery heating command; According to the q-axis current command, the PI controller outputs the q-axis voltage to control the q-axis current with an output value of zero; The d-axis voltage is output via hysteresis control based on the d-axis current command. A random factor is generated at a preset frequency, and the amplitude of the d-axis voltage is adjusted according to the random factor to randomly adjust the current slope of the motor at each pulse current point, thereby generating a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed; The adjustment of the amplitude of the d-axis voltage according to the random factor includes: The real-time amplitude of the d-axis voltage is obtained, and the amplitude of the d-axis voltage is adjusted by multiplying the real-time amplitude by the random factor; The step of adjusting the amplitude of the d-axis voltage according to the random factor to randomly adjust the current slope of the motor at each pulse current point and generate a random pulse current acting on the power battery includes: The positive relationship between the d-axis voltage and q-axis voltage and the slopes of the d-axis current and q-axis current, respectively, is determined based on the motor voltage equation. Based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate a random pulse current acting on the power battery. The voltage equation is as follows: in, , These are the d-axis voltage and q-axis voltage, respectively, and Rs is the phase resistance; , ω represents the d-axis current and q-axis current; Ld and Lq represent the d-axis inductance and q-axis inductance, respectively; ψf represents the magnetic flux linkage. Based on the above voltage equation, the motor speed is 0 during the power battery heating process, the motor is stationary, the back electromotive force term introduced by the rotation is ignored, the motor phase resistance is low, and the voltage drop of the phase resistance is ignored, thus obtaining the following equations (1) and (2): (1) (2) Among them, , The d-axis current slope and q-axis current slope are respectively, so that when the motor is at a certain pulse current point, the current rise or fall slope of the next pulse is determined by the magnitude of the currently injected voltage. Thus, based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate random pulse currents acting on the power battery.

2. The noise processing method according to claim 1, characterized in that: The random factor is set to a random number in the range of 0.2-1 generated according to a preset random function.

3. The noise treatment method according to claim 1, characterized in that, The q-axis current with a control output value of zero also includes: Injecting a tooth-like current into the q-axis suppresses the mechanical vibration of the motor.

4. A noise reduction device for heating a power battery, characterized in that, include: The receiving module is used to receive the power battery heating command and generate d-axis current command and q-axis current command according to the power battery heating command; The first processing module is used to output the q-axis voltage through the PI controller according to the q-axis current command, so as to control the q-axis current with an output value of zero. The second processing module is used to control the hysteresis control to output the d-axis voltage according to the d-axis current command. The adjustment module is used to generate a random factor at a preset frequency, adjust the amplitude of the d-axis voltage according to the random factor, and randomly adjust the current slope of the motor at each pulse current point to generate a random pulse current acting on the power battery, so that the noise generated during the battery heating process is randomly distributed. The adjustment of the amplitude of the d-axis voltage according to the random factor includes: The real-time amplitude of the d-axis voltage is obtained, and the amplitude of the d-axis voltage is adjusted by multiplying the real-time amplitude by the random factor; The step of adjusting the amplitude of the d-axis voltage according to the random factor to randomly adjust the current slope of the motor at each pulse current point and generate a random pulse current acting on the power battery includes: The positive relationship between the d-axis voltage and q-axis voltage and the slopes of the d-axis current and q-axis current, respectively, is determined based on the motor voltage equation. Based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate a random pulse current acting on the power battery. The voltage equation is as follows: in, , These are the d-axis voltage and q-axis voltage, respectively, and Rs is the phase resistance; , ω represents the d-axis current and q-axis current; Ld and Lq represent the d-axis inductance and q-axis inductance, respectively; ψf represents the magnetic flux linkage. Based on the above voltage equation, the motor speed is 0 during the power battery heating process, the motor is stationary, the back electromotive force term introduced by the rotation is ignored, the motor phase resistance is low, and the voltage drop of the phase resistance is ignored, thus obtaining the following equations (1) and (2): (1) (2) Among them, , The d-axis current slope and q-axis current slope are respectively, so that when the motor is at a certain pulse current point, the current rise or fall slope of the next pulse is determined by the magnitude of the currently injected voltage. Thus, based on the positive change relationship, the current slope of the motor at each pulse current point is randomly adjusted according to the q-axis voltage and the adjusted d-axis voltage to generate random pulse currents acting on the power battery.

5. An electric vehicle, characterized in that: The noise reduction device for power battery heating described in claim 4 above is applied.

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