Motor controller for realizing pulse heating music noise reduction

Abstract

The invention provides a motor controller for realizing pulse heating music noise reduction, the motor controller comprises an inverter circuit, the inverter circuit comprises three phases of switch tube bridge arms, the bridge arm midpoint of each switch tube bridge arm is used for connecting a phase winding of a driving motor, and the bridge arm midpoint of each switch tube bridge arm is used for connecting a phase winding of the driving motor. A bridge arm midpoint of a three-phase switch tube bridge arm of the inverter circuit is used for outputting three-phase current to a winding of the driving motor, and the frequency of each phase of current in the three-phase current in each period is controlled to be one frequency or 2N times of the frequency in a set frequency set, so that the heating efficiency is improved on the premise that the heating efficiency is not changed. The noise energy generated by the high-frequency vibration generated by the motor winding under the action of the high-frequency signal is dispersed to a wide frequency range, and in addition, the specific music melody is formed by combining the high-frequency vibration, so that the noise perception of a user at the specific frequency during heating can be further reduced, and better user experience is provided.

Description

Technical Field

[0001] The present application relates to the field of battery heating, and in particular to a motor controller for realizing pulse heating music noise reduction. Background Art

[0002] In low temperature environments, the charging and discharging capacity of electric vehicle power batteries drops sharply, so it is necessary to heat the power batteries to ensure normal driving of electric vehicles. Currently, the more common heating methods include positive temperature coefficient ceramic heating mode (PTC) and motor active heating. The above heating methods all heat the battery through a heating water channel, and the heating rate is not high, which affects the user experience.

[0003] In addition, high-frequency pulse heating can also be used to heat the power battery. It mainly uses the powertrain to perform AC high-frequency charging and discharging on the power battery, thereby using the heat generated by the battery's own internal resistance to heat the battery. Among them, pulse alternating current is achieved by injecting high-frequency voltage. The high-frequency voltage acts on the motor windings, which will generate a high-frequency magnetic field consistent with the injection frequency. At this time, the motor is similar to an acoustic device. The motor windings generate high-frequency vibrations under the action of high-frequency signals, thereby generating noise. Since the frequency of the injected signal is single and fixed, the generated noise is sharp and harsh. In view of this, it is necessary to avoid noise during the heating process to optimize the user's driving experience. Summary of the invention

[0004] The present application proposes a motor controller for realizing pulse heating music noise reduction, which controls the frequency of each phase current in each cycle to be a frequency in a set frequency set or 2 of the frequency. N Without changing the heating efficiency, the noise energy generated by the high-frequency vibration of the motor winding under the action of the high-frequency signal is dispersed into a wider frequency range. By combining the high-frequency vibrations to form a specific musical melody, the user's perception of noise at a specific frequency during heating can be further reduced, thereby providing a better user experience.

[0005] In a first aspect, the present application provides a motor controller for realizing pulse heating music noise reduction, the motor controller includes an inverter circuit, the inverter circuit includes a three-phase switch tube bridge arm, the bridge arm midpoint of each phase switch tube bridge arm is used to connect a phase winding of a drive motor, the inverter circuit is used to connect a power battery through a DC bus, the motor controller is used to: control the bridge arm midpoint of the three-phase switch tube bridge arm of the inverter circuit to output a three-phase current to the winding of the drive motor, the three-phase current is used to generate pulse alternating current on the DC bus, the pulse alternating current is used to heat the power battery, and the frequency of each phase of the three-phase current in each cycle is controlled to be a set frequency in a set frequency set or twice a set frequency in a set frequency set N times, N is an integer.

[0006] The present invention sets the frequency of each phase current in each cycle of the three-phase current to be one frequency in the set frequency set or 2 of the frequency. N times, so that the frequency of each phase current flowing through the drive motor winding is dispersed in the set frequency set, and then the vibration frequency generated by each winding under the action of the rapidly changing current is also different. Therefore, if the frequency of each phase current in each cycle is a frequency in the set frequency set or twice that frequency, N times, the sound generated by the driving motor winding in multiple cycles will have at least different frequencies, and since each cycle is very short, the sound energy generated by the vibration can be dispersed into a wider frequency range, so that the sound is reduced and persists at a specific frequency. By combining high-frequency vibrations to form a specific musical melody, the user's perception of noise at a specific frequency during heating can be further reduced, thereby providing a better user experience.

[0007] As a possible implementation, each set frequency in the set frequency set is a frequency corresponding to a note. The set frequency set includes 12 set frequencies, N is less than or equal to 7, and N is greater than or equal to -7.

[0008] By setting the high-frequency vibration frequency to the frequency corresponding to different notes of music, the present application can transform the originally harsh noise into the melody of a song composed of notes, thereby significantly reducing the user's sensitivity to noise and improving riding comfort.

[0009] When the range is set to the piano range, the piano range is from A0 to C7. If the set frequency is the frequency corresponding to C0, then 2 of the set frequency N times, up to 2 times the frequency of C0 7 Therefore, N is less than or equal to 7, and if the set frequency is C7, then 2 of the set frequency N times, up to 2 times the frequency of C7 -7 times, therefore, N is greater than or equal to -7.

[0010] As a possible implementation, the motor controller is used to control the frequency of each phase of the three-phase current to change periodically and to control the frequency of each phase of the three-phase current to change the same within each change period.

[0011] By dispersing the noise energy generated by high-frequency vibrations over a wider frequency range, the perception of noise at a specific frequency is reduced. The periodic frequency changes help to form a specific note melody, which can further reduce harsh noise and enhance the user's auditory experience, thereby improving the overall comfort and user satisfaction of electric vehicles while maintaining battery heating efficiency.

[0012] In order to reduce the perception of noise at a specific frequency and make the sound corresponding to the continuous high-frequency vibration generated by the driving motor winding appear as a specific melody, thereby forming a specific song, as a possible implementation method, the motor controller is used to control the frequency of each phase of the three-phase current and the note frequency of the melody of a song in a preset song library to correspond one by one in the process of controlling the periodic change of the frequency of each phase of the three-phase current.

[0013] During each change cycle, the sound generated by the three-phase current on the windings of the drive motor can constitute the melody of a song in the preset song library, thereby converting the noise into a specific song, which can provide users with a better auditory experience and increase the fun of driving.

[0014] As a possible implementation, in each variation cycle, the sound generated by the three-phase current on the windings of the drive motor constitutes the melody of a song in a preset song library.

[0015] By controlling the frequency of each phase of the three-phase current in multiple consecutive cycles to correspond one-to-one with the frequency of each note of a specific song, the sound generated on the winding of the drive motor can constitute the melody of a song in the preset song library, heating the power battery while improving the driving experience.

[0016] As a possible implementation, the motor controller is used to control the frequency difference of each phase current of the three-phase current in any two adjacent cycles to be less than a set frequency threshold.

[0017] By limiting the frequency variation within adjacent cycles, high-frequency vibrations of a fixed frequency can be avoided, thereby reducing the noise generated at a specific frequency. Controlling the frequency variation within adjacent cycles to a smaller amplitude can make the current change smoother and reduce the rapid changes in the electromagnetic field caused by mutations. Smooth current changes help reduce the high-frequency vibration of the winding, thereby reducing the sound waves and noise caused by vibration, reducing sharp and harsh sounds, and significantly improving the ride comfort of electric vehicles.

[0018] As a possible implementation, the motor controller is used to control the waveform of each phase current of the three-phase current to be a unilateral waveform.

[0019] As a possible implementation manner, the frequency of the direct-axis current signal of the three-phase current in each cycle is any one of a set frequency set, and the type of the direct-axis current signal includes at least one of the following: a sine wave, a triangle wave, and a square wave.

[0020] As a possible implementation, the motor controller is used to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be the same. By controlling the volt-second product of the direct-axis current signal of each phase current of the three-phase current in each cycle to be the same, the heating process of the power battery is optimized and the stability of the power battery heating power is ensured.

[0021] As a possible implementation, the motor controller is used to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a first volt-second product in response to the temperature of the power battery being a first temperature, and to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a second volt-second product in response to the temperature of the power battery being a second temperature. The first temperature is lower than the second temperature, and the first volt-second product is greater than the second volt-second product.

[0022] In low temperature environments, by increasing the volt-second product to provide stronger heating power, the battery temperature can be quickly increased to ensure battery performance and endurance. In high temperature environments, by reducing the volt-second product to reduce heating power, unnecessary energy consumption can be avoided, overall energy efficiency can be improved, and aging and damage of the power battery at excessively high temperatures can be avoided, thereby extending the battery life. It can also effectively prevent the battery from overheating and reduce safety risks caused by overheating.

[0023] As a possible implementation, the motor controller includes a control circuit, which is used to output a control signal to the inverter circuit, and the control signal is used to control the inverter circuit to output a three-phase current, wherein: the control signal is used to indicate the frequency and amplitude of the direct-axis current component of the three-phase current and to indicate that the quadrature-axis current component of the three-phase current is zero.

[0024] The quadrature-axis current component of the three-phase current provided in the embodiment of the present application is smaller than a preset value, thereby preventing unexpected torque from being transmitted to the wheels to generate vibration and noise, which affects the riding experience of the electric vehicle.

[0025] In a second aspect, the present application provides a powertrain, comprising the motor controller and heat exchange circuit of the first aspect, wherein the three-phase current is used to heat the windings of the drive motor, and the heat exchange circuit is used to transfer the heat generated by the windings of the drive motor to the power battery.

[0026] In a third aspect, the present application provides a method for controlling pulse heating of a power battery using music noise reduction, the method comprising: after a user starts a pulse heating function, controlling the midpoint of a bridge arm of a three-phase switch tube bridge arm of an inverter circuit to output a three-phase current to a winding of a drive motor, the three-phase current being used to generate pulse alternating current on a DC bus, the pulse alternating current being used to heat a power battery; controlling the frequency of each phase of the three-phase current in each cycle to be a set frequency in a set frequency set or twice a set frequency in a set frequency set N times, N is an integer, and each set frequency in the set frequency set is the frequency corresponding to a note.

[0027] As a possible implementation, the pulse heating control method also includes, in response to a user selecting a song after starting the pulse heating function, controlling the frequency of each phase of the three-phase current during the changing process to correspond one-to-one with the note frequency of the melody of a song in a preset song library, so that the sound generated by the three-phase current on the winding of the drive motor constitutes the melody of a song in the preset song library.

[0028] As a possible implementation, the pulse heating control method also includes, in response to a user executing a song switching operation, controlling the melody composed of the sound generated by the three-phase current on the winding of the drive motor to switch from one song to another song in a preset song library.

[0029] As a possible implementation, the pulse heating control method further includes controlling the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a powertrain provided in an embodiment of the present application;

[0032] Figure 3 A schematic diagram of a motor controller provided in an embodiment of the present application;

[0033] Figure 4 A schematic diagram of the operation of a motor controller provided in an embodiment of the present application;

[0034] Figure 5 It is a structural schematic diagram of a control circuit in a motor controller;

[0035] Figure 6 It is the waveform diagram of the voltage given signal;

[0036] Figure 7 Schematic diagram of the frequencies corresponding to each note;

[0037] Figure 8 Schematic diagram of the direct-axis current signal waveform corresponding to different note combinations;

[0038] Fig. 9 A waveform diagram showing the user switching songs;

[0039] Fig.10 A schematic diagram of another powertrain provided in an embodiment of the present application;

[0040] Fig.11 A schematic diagram of another powertrain provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] The technical solutions involved in the specific implementation of the present application are described below in conjunction with the drawings in the implementation. Before describing the specific content of the technical solution, the terms used in the present application are briefly explained.

[0042] The words "first, second, third, etc." or module A, module B, module C and other similar terms in the specification and claims are only used to distinguish similar objects and do not represent a specific ordering of the objects. It is understandable that the specific order or sequence can be interchanged where permitted so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0043] The term "comprising" as used in the description and claims should not be interpreted as being limited to what is listed thereafter; it does not exclude other elements or steps. Therefore, it should be interpreted as specifying the presence of the mentioned features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components and groups thereof. Therefore, the expression "a device comprising means A and B" should not be limited to a device consisting of components A and B only.

[0044] References to "one embodiment" or "an embodiment" in this specification mean that a particular feature, structure, or characteristic described in conjunction with the embodiment is included in at least one embodiment of the present application. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in various places in this specification do not necessarily refer to the same embodiment, but may refer to the same embodiment. In addition, in one or more embodiments, the particular features, structures, or characteristics can be combined in any appropriate manner, as would be apparent to one of ordinary skill in the art from this disclosure.

[0045] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present application. In case of any inconsistency, the meaning described in this specification or the meaning derived from the contents recorded in this specification shall prevail. In addition, the terms used herein are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0046] The motor of an electric vehicle is generally an AC motor, while the power battery is a DC source. Therefore, the DC output of the power battery is converted into the three-phase AC of the motor through an inverter circuit. The coordinate axes of the three-phase AC are U axis, V axis and W axis. The three phases of AC can also be called U phase, V phase and W phase respectively. In order to simplify the analysis of the motor, the static three-phase coordinates are usually transformed into rotating dq coordinates. This transformation is called Park transformation. In the dq coordinate system, the three coordinate axes are called direct axis, quadrature axis and zero axis respectively.

[0047] The direct axis, also known as the D axis or d-axis, is a time-varying DC coordinate axis obtained by Park transformation of the stationary U / V / W three-phase coordinate axes.

[0048] The quadrature axis, also known as the Q axis or q-axis, is a time-varying AC coordinate axis obtained by Park transformation of the stationary U / V / W three-phase coordinate axes.

[0049] The zero axis, also known as the 0 axis or 0-axis, is the coordinate axis perpendicular to the dq plane where the direct axis and the quadrature axis are located.

[0050] Specifically, the formula for the Parker transformation can be shown as follows:

[0051]

[0052] Among them, θ is the angle between the d-axis and the U-axis, I_d is called the direct-axis current, which is mainly used to adjust the magnetic field, I_q is called the quadrature-axis current, which is mainly used to adjust the torque, I_0 is called the zero-sequence current, I_u, I_v, and I_w are the currents on the U-axis, V-axis, and W-axis, respectively, that is, the three-phase current.

[0053] The above matrix is ​​the expression of the three-phase current transformed into I_d, I_q, I_0. By performing an inverse transformation on the matrix, we can obtain the expression of the three-phase current transformed from I_d, I_q, I_0, which will not be repeated here.

[0054] Since the three-phase current is the current corresponding to the winding in the motor, when outputting current to the direct axis of the motor, the motor controller needs to convert I_d into three-phase currents I_u, I_v, I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, I_w into the motor winding. When outputting current to the zero axis of the motor, the motor controller needs to convert I_0 into three-phase currents I_u, I_v, I_w through the inverse transformation of the Park transformation, and pass I_u, I_v, I_w into the motor winding. The quadrature-axis voltage / current is used to control the torque output by the drive motor, and the direct-axis voltage / current is used to control the direction and magnitude of the magnetic field generated by the drive motor.

[0055] The electric vehicle includes a drive motor, a motor controller, and a power battery. The motor controller receives the electric energy from the power battery and supplies power to the drive motor, which is used to drive the wheels of the electric vehicle to rotate so that the electric vehicle can travel.

[0056] Temperature has a great impact on power batteries. When charging and discharging power batteries at low temperatures, lithium deposition will occur, causing power battery capacity decay and even potential safety hazards. Therefore, the power battery needs to be heated to a certain temperature before the electric vehicle is allowed to drive.

[0057] There are three main ways to heat power batteries:

[0058] One way to heat a power battery is to use an external heating system to heat the power battery. For example, a power battery thermal circuit is provided outside the power battery, and a heat-carrying fluid that carries heat is provided in the power battery thermal circuit. A positive temperature coefficient resistor (PTC) heats the heat-carrying fluid in the power battery thermal circuit, and the heat-carrying fluid in the power battery thermal circuit conducts heat to the power battery to heat the power battery. Since the above method requires first heating the heat-carrying fluid in the power battery thermal circuit, and then heating the power battery through the heat-carrying fluid in the power battery thermal circuit, the heat transfer path is long and the heating efficiency is low.

[0059] One way to heat the power battery is to use active electric drive heating. The active electric drive heating method uses the motor excitation current to generate heat on the drive motor to heat the power battery. The motor controller outputs three-phase alternating current to the drive motor, and the three-phase alternating current makes the torque of the drive motor zero. The excitation current generates heat on the drive motor windings, and the heat generated on the drive motor is transferred to the power battery through the heat exchange circuit between the drive motor and the power battery for heating. In the above method, since the heat of the drive motor needs to be transferred to the power battery through the heat exchange circuit, the above heating method has the disadvantages of a long heat transfer path, a low power battery heating rate, and a low heating efficiency.

[0060] One way to heat the power battery is high-frequency pulse heating. The high-frequency pulse heating method uses the high-frequency pulse alternating current generated by the motor controller to heat the power battery. The bridge arm circuit of the motor controller generates high-frequency pulse alternating current. When the high-frequency pulse alternating current passes through the power battery, it generates heat on the internal resistance of the power battery and heats the power battery. The high-frequency heating method has the advantage of fast heating rate and is widely recognized.

[0061] Since the pulsed alternating current generated by the motor controller is formed by superposition of three phase currents, if high-frequency pulsed alternating current is to be achieved, a high-frequency voltage signal can be injected into the control circuit in the motor controller to control the three bridge arm circuits. First, the high-frequency voltage signal will be converted into a control signal, and the three bridge arm circuits of the motor controller will be controlled by the control signal. When the winding of the drive motor is acted upon by the control signal converted from the high-frequency voltage signal, the current flowing through the winding of the drive motor will change rapidly in a very short time due to the very short cycle of the control signal. This rapidly changing current will generate a changing electromagnetic field on the winding, and the magnetic field will cause high-frequency vibration of the winding itself. The high-frequency vibration will cause each part of the winding to vibrate with a small amplitude. These small amplitude vibrations will be converted into sound waves through the resonance, friction and air conduction of the material. At this time, the drive motor is similar to an acoustic device, thereby generating noise, and since the frequency of the high-frequency voltage signal is fixed, the noise finally generated also has a fixed frequency. If this frequency is within the frequency range that the human ear can hear, it will be perceived as a sharp and harsh sound, bringing a bad user experience.

[0062] In view of this, the embodiments of the present application provide a motor controller, a powertrain and an electric vehicle for realizing pulse heating music noise reduction, by controlling the frequency of each phase current in each cycle of the three-phase current to be a frequency in a set frequency set or to be twice the frequency. N times, thereby dispersing the noise energy generated by the high-frequency vibration of the motor winding under the action of the high-frequency signal into a wider frequency range without changing the heating efficiency. By combining the high-frequency vibrations to form a specific musical melody, the user's perception of noise at a specific frequency during heating can be further reduced, thereby providing a better user experience.

[0063] Figure 1 A schematic diagram of an electric vehicle provided in an embodiment of the present application. Figure 1 As shown, the electric vehicle 10 includes wheels 20, a power battery 13, and a power assembly 14. The power assembly 14 is used to receive power from the power battery 13 to drive the wheels 20 or to heat the power battery 13.

[0064] Figure 2 A schematic diagram of a powertrain provided in an embodiment of the present application. Figure 2As shown, the powertrain 14 includes a drive motor 11 and a motor controller 12. The motor controller 12 receives direct current from the power battery 13 and converts the direct current into three-phase alternating current to power the drive motor 11. The drive motor 11 and the wheels 20 are connected through a reducer or a transmission. When the electric vehicle 10 is running, the torque of the drive motor 11 is transmitted to the wheels 20 to provide power for the electric vehicle 10.

[0065] Figure 3 A schematic diagram of a motor controller provided in an embodiment of the present application. Figure 3 As shown, the motor controller 12 includes a control circuit 121, an inverter circuit 122 and a bus capacitor C. One end of the bus capacitor C is used to connect to the positive electrode of the power battery 13, and the other end of the bus capacitor C is used to connect to the negative electrode of the power battery 13. The inverter circuit 122 includes a three-phase switch tube bridge arm, and the two ends of each switch tube bridge arm are respectively connected to the two ends of the bus capacitor C, and the midpoint of each switch tube bridge arm is respectively used to connect to a phase winding of the drive motor 11. The rotor position signal output end of the drive motor 11 is connected to the signal acquisition end of the control circuit 121, and the two ends of the inverter circuit 122 are respectively connected to the positive and negative electrodes of the power battery 13, forming a power battery pulse heating circuit.

[0066] Exemplarily, the control circuit 121 may include, but is not limited to, a central processing unit (CPU), other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. The control circuit 121 can control the switch in each bridge arm to be turned on or off by outputting a control signal to each bridge arm of the inverter circuit 122. Among them, the control signal can be a pulse width modulation (PWM) signal. Exemplarily, the control circuit 121 can connect the gates of each switch tube of the three bridge arms in the inverter circuit 122 to control the conduction or shutdown of each switch tube in the inverter circuit 122. In some application scenarios, the control circuit 121 can combine the space vector pulse width modulation (SVPWM) technology to generate control signals for each switch of the three bridge arms.

[0067] The specific process of high-frequency pulse heating of the motor controller 12 is introduced below in conjunction with a specific embodiment.

[0068] The motor controller 12 starts the drive motor 11 , and the three bridge arms in the inverter circuit 122 can convert the DC current provided by the power battery 13 into AC current, and provide the AC current to the drive motor 11 , so that the drive motor 11 outputs torque to drive the wheels of the electric vehicle 10 .

[0069] When the temperature of the power battery 13 is too low, the motor controller 12 sends a control signal to the three bridge arms, and the midpoint of the three-phase switch tube bridge arm outputs a three-phase current to the winding of the drive motor, causing the internal resistance of the power battery to heat up, thereby heating the power battery.

[0070] The control circuit 121 in the motor controller 12 is used to: drive the operation of the upper bridge arm switch tube and the lower bridge arm switch tube of each switch tube bridge arm, and control the frequency of each phase current of the three-phase current in each cycle to be a set frequency in the set frequency set or 2 times a set frequency in the set frequency set. N times.

[0071] The control circuit 121 is used to output a control signal to the inverter circuit 122, and the control signal is used to control the inverter circuit 122 to output a three-phase current, wherein: the control signal is used to indicate the frequency and amplitude of the direct-axis current component of the three-phase current and to indicate that the quadrature-axis current component of the three-phase current is zero.

[0072] Since the frequency of each phase current in each cycle is a frequency in the set frequency set or twice the frequency N times, so the frequency of each phase current flowing through the winding of the drive motor 11 is dispersed in the set frequency set, and then the vibration frequency generated by each winding under the action of the rapidly changing current is also relatively dispersed.

[0073] Therefore, if the frequency of each phase current in each cycle is a frequency in the set frequency set or twice the frequency N times, the vibration generated by the winding of the driving motor 11 in each cycle also has more than two frequencies, and since the time of each cycle is very short, the sound energy generated by the vibration will be dispersed into a wider frequency range, so that the sound corresponding to the vibration generated by the winding of the driving motor 11 is reduced and continued at a specific frequency, thereby providing a better user driving experience.

[0074] The bus current is formed by the superposition of three phase currents, so the amplitude of each phase current determines the amplitude of the bus current. If the amplitude of each phase current of the three-phase current can be kept the same in any two adjacent cycles, the magnitude of the bus current formed by the superposition of the three-phase current can also be kept the same in any two adjacent cycles. If the bus current can be kept the same in any two adjacent cycles, the heating power of the power battery 13 will be relatively stable under the action of the bus current, thereby optimizing the heating process of the power battery 13.

[0075] In order to further reduce noise, the frequency of the positive half cycle and the frequency of the negative half cycle of each phase current of the three-phase current in the same cycle can also be a set frequency in the set frequency set or twice a set frequency in the set frequency set. N times.

[0076] If the frequency of the positive half cycle and the negative half cycle of each phase current in the same cycle is a set frequency in the set frequency set or 2 times a set frequency in the set frequency set N times, it means that the frequency of each phase current is different within one cycle. Furthermore, the vibration frequency of the winding of the drive motor 11 is also different within one cycle, so the sound corresponding to the vibration generated by the winding of the drive motor 11 can be reduced and continued at a specific frequency. Therefore, the present application adopts this method to more evenly disperse the noise energy generated by the vibration into a wider frequency range, thereby further reducing the perception of noise at a specific frequency.

[0077] The control circuit 121 controls the bridge arm of the three-phase switch tube bridge arm through the control signal. The three bridge arms included in the inverter circuit 122 can be respectively recorded as the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm. Figure 3 As shown, the upper bridge switch tube in the U-phase bridge arm is the switch tube Q1, and the lower bridge switch tube is the switch tube Q2. The upper bridge switch tube in the V-phase bridge arm is the switch tube Q3, and the lower bridge switch tube is the switch tube Q4. The upper bridge switch tube in the W-phase bridge arm is the switch tube Q5, and the lower bridge switch tube is the switch tube Q6. One end of each bridge arm is used to connect to one end of the power battery 13, that is, the collector of the switch tube Q1, the collector of the switch tube Q3, and the collector of the switch tube Q5 are connected to one end of the power battery 13. The other end of each bridge arm is connected to the other end of the power battery 13, that is, the emitter of the switch tube Q2, the emitter of the switch tube Q4, and the emitter of the switch tube Q6 are connected to the other end of the power battery 13. Optionally, one end of the power battery 13 may be the positive terminal of the power battery 13, and the other end of the power battery 13 may be the negative terminal of the power battery 13. Alternatively, one end of the power battery 13 may be the negative terminal of the power battery 13, and the other end of the power battery 13 may be the positive terminal of the power battery 13.

[0078] Optionally, the upper bridge switch tube can be an insulated gate bipolar transistor (IGBT) and its anti-parallel diode, or a metal oxide semiconductor field effect transistor (MOSFET), etc. The present application does not make too many restrictions on the specific structure inside the upper bridge switch tube. Optionally, the lower bridge switch tube can be an IGBT and its anti-parallel diode or a MOSFET. The present application does not make too many restrictions on the specific structure inside the lower bridge switch tube.

[0079] Among them, the control circuit 121 is used to control the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on circumferentially through control signals, so that the power battery 13, the turned-on upper bridge switch tube, the two-phase winding of the drive motor, and the turned-on two lower bridge switch tubes form a discharge loop, and the internal resistance of the power battery 13 generates heat under the action of the current in the discharge loop, so as to achieve heating of the power battery 13. Alternatively, the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are turned on circumferentially, so that the power battery 13, the turned-on lower bridge switch tube, the two-phase winding of the drive motor, and the turned-on two upper bridge switch tubes form a discharge loop, and the internal resistance of the power battery 13 generates heat under the action of the current in the discharge loop, so as to achieve heating of the power battery 13.

[0080] The control signal is used to indicate the direct-axis current component and the quadrature-axis current component of the three-phase current. Since the direct-axis current component is used to control the direction and magnitude of the magnetic field generated by the drive motor 11, the quadrature-axis current component is used to control the torque output by the drive motor 11. If you want to control the frequency of each phase of the three-phase current in each cycle to be a set frequency in the set frequency set or 2 times a set frequency in the set frequency set N times, it is necessary to specifically control the frequency of the direct-axis current component.

[0081] like Figure 4As shown, the control circuit 121 of the motor controller 12 specifically includes a quadrature-axis current controller 401 and a direct-axis current controller 402. In the embodiment of the present application, the motor controller 12 is used to receive a heating instruction, and determine the quadrature-axis current component determined by the quadrature-axis current controller 401 and the direct-axis current component determined by the direct-axis current controller 402 according to the heating power of the power battery 13 indicated by the heating instruction. The control circuit 121 may also include a Park's transmission module and a Clarke's transmission module. The Parke's transmission module is used to convert two components in the αβ coordinate system into an orthogonal rotating coordinate system (dq), and the Clarke's transmission module converts the time domain components of the three-phase system (in the abc coordinate system) into two components in the orthogonal stationary coordinate system (αβ). In an embodiment of the present application, the Park transformation module receives the quadrature-axis voltage signal Uq and the direct-axis voltage signal Ud, and performs an inverse Park transformation on the signals Uq and Ud in the direct-quadrature axis coordinate system to obtain voltage signals Uα and Uβ in the αβ coordinate system, and generates a control signal based on the Uα and Uβ signals, and the control signal is used to control the conduction frequency and duty cycle of the switching tube of the inverter circuit 122.

[0082] Among them, the cross-axis current component is used to control the torque output by the drive motor 11. During the high-frequency pulse heating process of the power battery 13, if the cross-axis current component of the drive motor 11 is not less than the preset value, the drive motor 11 will produce unexpected torque output. The unexpected torque of the drive motor 11 is transmitted to the wheel 20, which will cause the electric vehicle 10 to generate vibration and noise, affecting the riding experience of the electric vehicle 10. Therefore, the cross-axis current component of the three-phase current provided in the embodiment of the present application is less than the preset value, thereby avoiding the unexpected torque from being transmitted to the wheel to generate vibration and noise, affecting the riding experience of the electric vehicle. Optionally, the caliper in the electronic parking brake system (EPB) of the electric vehicle 10 can be in a locked state to ensure that the wheels of the electric vehicle 10 do not move.

[0083] Among them, the direct-axis current component is used to control the direction and magnitude of the magnetic field generated by the drive motor 11. By controlling the direction and magnitude of the magnetic field generated by the drive motor 11, the magnitude and direction of the bus current can be adjusted, thereby realizing the adjustment of the heating power of the power battery 13 and the elimination of noise during the heating process. Specifically, the direct-axis current component can be determined according to the heating power of the power battery 13 indicated by the heating instruction. Among them, the direct-axis current component includes two parameters, one is the frequency and amplitude of the direct-axis voltage, and the other is the bias of the direct-axis voltage. Optionally, the direct-axis current component may include a voltage given signal and a direct-axis bias signal, the voltage given signal is used to indicate the frequency and amplitude of the voltage, and the direct-axis bias signal is used to make the voltage generate a DC bias. That is to say, the final motor controller inputs the direct-axis voltage signal with a DC bias into the control circuit 121, so that the control circuit 121 generates a control signal according to the direct-axis voltage signal, and then uses the control signal to drive the drive motor 11. Among them, the direct-axis voltage signal with a DC bias can increase the effective value of the three-phase current of the drive motor 11, thereby improving the heating efficiency of the power battery. It should be noted that the DC bias of the direct-axis voltage signal may be a positive DC bias or a negative DC bias, and those skilled in the art may set it individually according to the demand for heating power.

[0084] See also Figure 5 As shown, the control circuit 121 includes a park's transmission module, an inverse park's transformation and a clark's transmission module. The park's transformation module is used to convert two components in the αβ coordinate system into an orthogonal rotating coordinate system (dq). The clark's transformation module converts the time domain components of the three-phase system (in the abc coordinate system) into two components in the orthogonal stationary coordinate system (αβ). Specifically, in an embodiment of the present application, the park's transformation module receives the quadrature-axis voltage signal Uq and the direct-axis voltage signal Ud, and performs an inverse park's transformation on the signals Uq and Ud in the direct-quadrature axis coordinate system to obtain the voltage signals Uα and Uβ in the αβ coordinate system. The drive circuit generates a PWM control signal according to the Uα and Uβ signals, and the PWM control signal is used to control the conduction frequency and duty cycle of the switch tube of the three-phase bridge arm.

[0085] On the other hand, the current sensor collects the three-phase current signal i of the drive motor 11 a 、i b 、i c The Clarke transformation module is used to transform the current signal i in the three-phase coordinate system a 、i b 、i c Converted into the current signal i in the αβ coordinate system α 、i βThen the Park transform module transforms the current signal i in the αβ coordinate system α 、i β Perform Park transformation to convert the current signal i in the αβ coordinate system α 、i β Converted into the current signal i in the direct-quadrature coordinate system d 、i q ,i q As the quadrature axis current feedback signal, i d After the high-frequency signal components are filtered out by a low-pass filter, it is output as a direct-axis current feedback signal. By controlling the frequency of each phase current of the three-phase current output by the drive motor power circuit, the high-frequency noise in the power battery heating process is optimized, thereby improving the user experience.

[0086] As a possible implementation, the motor controller includes a control circuit, which is used to output a control signal to the inverter circuit, and the control signal is used to control the inverter circuit to output a three-phase current, wherein: the control signal is used to indicate the frequency and amplitude of the direct-axis current component of the three-phase current and to indicate that the quadrature-axis current component of the three-phase current is zero.

[0087] Continue as Figure 5 As shown, the control circuit also includes a drive motor direct-axis current feedback control circuit and a drive motor cross-axis current feedback control circuit, wherein: the drive motor direct-axis feedback control circuit is used to receive a drive motor direct-axis current given signal and a direct-axis current feedback signal of the drive motor three-phase current and output a drive motor direct-axis current feedback control signal, the drive motor direct-axis feedback control circuit is used to receive a drive motor cross-axis current given signal and a cross-axis current feedback signal of the drive motor three-phase current and output a drive motor cross-axis current feedback control signal, and the drive motor direct-axis current feedback signal and the drive motor cross-axis current feedback control signal are used to adjust the phase, frequency and amplitude of the drive motor three-phase current.

[0088] The drive motor control circuit includes a drive motor direct-axis current feedback control circuit and a drive motor quadrature-axis current feedback control circuit. The drive motor quadrature-axis current feedback control circuit generates a quadrature-axis voltage according to the quadrature-axis current indicated by the quadrature-axis current given signal and inputs it to the drive motor. At the same time, the drive motor quadrature-axis current feedback control circuit adjusts the size of the quadrature-axis current given signal according to the quadrature-axis current of the drive motor indicated by the quadrature-axis current feedback signal collected from the drive motor to realize closed-loop control of the quadrature-axis current.

[0089] As a possible implementation, the control circuit includes a drive motor voltage signal generator, and the drive motor voltage signal generator is used to output a drive motor voltage given signal according to a drive motor voltage frequency signal and a drive motor voltage amplitude signal.

[0090] Among them, the quadrature-axis component of the three-phase current of the driving motor and the quadrature-axis component of the three-phase current of the electric motor are zero, or the torque values ​​of the three-phase motor of the driving motor and the three-phase motor of the electric motor are less than the preset torque value.

[0091] In the embodiment of the present application, the cross-axis current indicated by the cross-axis current given signal is 0. As before, the cross-axis current of the drive motor 11 is used to control the torque output by the drive motor 11. During the high-frequency pulse heating process of the power battery 13, if the cross-axis current of the drive motor 11 is not zero, the drive motor 11 will have unexpected torque output. The unexpected torque of the drive motor 11 is transmitted to the wheels, which will cause vibration and noise in the power vehicle 10, affecting the riding experience of the power vehicle 10. If the cross-axis current of the drive motor 11 is open-loop controlled, it is difficult to accurately control the cross-axis current of the drive motor 11 to zero, so that the drive motor 11 is prone to produce unexpected torque. Therefore, the motor controller 12 provided in the embodiment of the present application can accurately control the cross-axis current to zero by performing closed-loop control on the cross-axis current of the drive motor 11, avoiding unexpected torque output of the drive motor 11, thereby improving the performance and driving comfort of the power vehicle 10.

[0092] As a possible implementation manner, the direct-axis current given signal of the driving motor is a DC bias signal, the quadrature-axis current given signal of the driving motor is 0, the direct-axis current given signal of the motor is a DC bias signal, the quadrature-axis current given signal of the motor is 0, and the DC bias is a positive DC bias or a negative DC bias.

[0093] In the embodiment of the present application, the motor controller 12 receives a heating instruction, and determines a direct-axis current given signal and a direct-axis current given signal according to the heating power of the power battery 13 indicated by the heating instruction.

[0094] In one embodiment, the direct-axis current injected into the drive motor 11 is a sine wave, but when the direct-axis voltage of the drive motor 11 is a sine wave, the ripple current of the high-frequency pulse current generated on the bus capacitor is large, which makes the heating efficiency of the power battery 13 low. In the embodiment of the present application, the direct-axis current injected into the drive motor 11 by the motor controller 12 is a square wave, and the direct-axis voltage of the drive motor 11 is a square wave, which can effectively reduce the ripple of the bus current of the bus capacitor and thus improve the heating efficiency of the power battery 13.

[0095] Continue reading Figure 5As shown, in order to achieve closed-loop control of the direct-axis current, the motor controller 12 provided in the embodiment of the present application includes a low-pass filter, which is used to filter the high-frequency component of the direct-axis current collected from the drive motor 11 so as to obtain the DC bias in the direct-axis current of the drive motor 11. The direct-axis current signal collected from the drive motor 11 is filtered out with the low-pass filter to obtain a direct-axis current feedback signal, and the direct-axis current control loop compares the direct-axis current feedback signal with the direct-axis current given signal and then adjusts the direct-axis current bias value. The direct-axis current given signal is superimposed with the square wave voltage signal to generate a square wave voltage signal.

[0096] like Figure 6 As shown, Figure 6 (a) in the figure is a waveform diagram of the voltage indicated by the voltage given signal, taking the waveform of the voltage given signal as a square wave as an example. Figure 6 (b) is the waveform of the bias voltage indicated by the direct axis bias signal. Figure 6 (c) in the figure is the waveform of the voltage given signal with DC bias, that is, Figure 6 The waveform of (c) is Figure 6 The voltage signal in (a) and Figure 6 It is formed by the superposition of (b) in (b).

[0097] In order to make the current of each phase in each cycle equal to one of the set frequencies in the set frequency set or two times one of the set frequencies in the set frequency set, N Therefore, the direct-axis current component of the three-phase current needs to be one of the set frequencies in the set frequency set or twice one of the set frequencies in the set frequency set in each cycle. N times. Among them, since the direct axis current component of the three-phase current is related to the direct axis current given signal input by the drive circuit. Therefore, when the direct axis current given signal is a set frequency in the set frequency set or 2 times of a set frequency in the set frequency set, N When the direct-axis current component of the three-phase current is one of the set frequencies in the set frequency set or two of one of the set frequencies in the set frequency set, N times.

[0098] As a possible implementation manner, the frequency of the direct-axis current signal in each cycle is a set frequency in the set frequency set or twice a set frequency in the set frequency set. N times. In addition, the type of the direct axis current given signal includes at least one of the following: a sine wave, a triangle wave, and a square wave. Those skilled in the art can determine the type of the voltage given signal according to the ripple current size of the pulsed alternating current and the heating efficiency, and no specific limitation is made here.

[0099] Exemplarily, in any two adjacent cycles of each cycle, the signal type of the direct-axis current given signal in the first cycle may be a first direct-axis current signal, and the signal type of the direct-axis current given signal in the second cycle may be a second direct-axis current signal.

[0100] The frequency of the first straight-axis current signal is a set frequency in the set frequency set or twice a set frequency in the set frequency set. N times, the frequency of the second direct-axis current signal is one of the set frequencies in the set frequency set or twice one of the set frequencies in the set frequency set N In this way, the direct axis current given signal is a set frequency in the set frequency set or 2 times of a set frequency in the set frequency set in any two adjacent cycles. N times, so that each phase current of the three-phase current can be a set frequency in the set frequency set or 2 times a set frequency in the set frequency set in any two adjacent cycles. N times.

[0101] Furthermore, in order to reduce the noise perception at a specific frequency, the motor controller 12 is configured to control the frequency difference of each phase current of the three-phase current in any two adjacent cycles to be less than a set frequency threshold.

[0102] By limiting the frequency variation within adjacent cycles, high-frequency vibrations of a fixed frequency can be avoided, thereby reducing the noise generated at a specific frequency. Controlling the frequency variation within adjacent cycles to a smaller amplitude can make the current change smoother and reduce the rapid changes in the electromagnetic field caused by mutations. Smooth current changes help reduce the high-frequency vibration of the winding, thereby reducing the sound waves and noise caused by vibration, avoiding sharp and harsh sounds, and significantly improving the ride comfort of electric vehicles.

[0103] In order to reduce the noise perception at a specific frequency and make the sound corresponding to the continuous high-frequency vibration generated by the winding of the driving motor 11 present as a specific melody, thereby forming a specific tune or piece of music, as a possible implementation, each set frequency in the set frequency set is a frequency corresponding to a note. The note is used to identify different pitches, and the note is in a set range, which is the range between the lowest frequency and the highest frequency that the sound source can produce.

[0104] See also Figure 7 , Figure 7 The following is a diagram of the frequencies corresponding to different notes. Each set frequency corresponds to a note in the song (such as C, D, E, etc.), which are used to identify different pitches.

[0105] The set frequency set can include 12 set frequencies. Exemplarily, each set frequency in the set frequency set can specifically include the following notes (note names): A, #A, B, C, #C, D, #D, E, F, #F, G, #G. The Chinese pronunciations of the above notes are: La, La, Si, Do, Do, Re, Re, Mi, Fa, Fa, Sol, Sol.

[0106] In addition, in another representation, each set frequency in the set frequency set may further include the following notes (note names): A, bB, B, C, bD, D, bE, E, F, bG, G, bA. In one-to-one correspondence, the Chinese pronunciations of the above notes are: La, Si, Do, Re, Re, Mi, Mi, Fa, Sol, Sol, La.

[0107] Optionally, the set range can be a commonly used piano range, which ranges from A0 (about 27.5Hz) to C7 (about 4186Hz). The set frequency corresponds to a note in the piano range (A0-C7). A note has different marks in different octaves. For example, A0 is a note A in the lowest octave, with a frequency of about 27.5Hz. A1 is one octave higher than A0, and the frequency corresponding to A1 is about 55Hz, ..., A7 is one octave higher than A6, and the frequency is about 3520Hz. In the same note, the frequency between each octave is twice that of the previous octave. For example, the frequency corresponding to A1 is twice that of A0, the frequency corresponding to A2 is twice that of A1, and so on. Although they are all notes A, each note A has different frequencies and pitches in different octaves, so that the music can cover a wide frequency range, thereby producing a richer timbre.

[0108] Therefore, the frequency of each phase of the three-phase current can be set to the set frequency or double the set frequency. N For example, if the set frequency is C4, the frequency of each phase of the three-phase current can also use C2 (about 65.41Hz), that is, 261.63Hz*2 -2 , C3 (about 130.81Hz) is 261.63Hz*2 -1 , C5 (about 523.25Hz) is 261.63Hz*2 1 、C6 (about 1046.5Hz) i.e. 261.63Hz*2 2 etc.

[0109] It should be noted that when the range is set to the piano range, since the piano range is from A0 to C7, if the set frequency is the frequency corresponding to C0, then 2 of the set frequency N times, up to 2 times the frequency corresponding to C0 7 times (i.e. C7), then N is less than or equal to 7, and if the set frequency is C7, then 2 of the set frequency N times, up to 2 times the frequency of C7 -7 times (i.e. C0), therefore, N is greater than or equal to -7.

[0110] In this way, the present application can transform the originally harsh noise into the melody of a song composed of musical notes by setting the high-frequency vibration frequency to the frequency corresponding to different musical notes, thereby significantly reducing the user's sensitivity to noise and improving riding comfort. In addition, transforming noise into a specific song can provide users with a rich auditory experience and increase the fun of driving.

[0111] In most songs, there are usually only a dozen common notes. Therefore, in the process of controlling the three-phase current, this feature can be used to reduce the perception of noise at specific frequencies and make the generated sound present a specific melody.

[0112] As a possible implementation, in each cycle, the number of times each phase current of the three-phase current is controlled to adopt the first set frequency is greater than the number of times other frequencies are adopted.

[0113] In most songs, only a dozen or so commonly used notes are frequently used. For example, the C3-B4 note interval is relatively common, and it is also a commonly used note in various songs. Therefore, for this application, in each cycle, each phase current of the three-phase current uses the frequency corresponding to the note in the C3-B4 note interval more times than the other frequencies. This means that most of the time, the current frequency will remain at the frequency corresponding to the note in the C3-B4 interval.

[0114] In this way, the frequency of each phase current of the three-phase current in each cycle is controlled to be one of the set frequencies in the set frequency set or two of them. N times (N is an integer), which can effectively reduce the noise perception at a specific frequency, convert the noise into a specific tune or song, and enhance the driving experience.

[0115] As a possible implementation, the motor controller 12 is used to control the frequency of each phase of the three-phase current to change periodically and control the frequency of each phase of the three-phase current to change the same in each change cycle. In order to form a specific frequency, the motor controller 12 is used to control the frequency of each phase of the three-phase current to change periodically.

[0116] By dispersing the noise energy generated by high-frequency vibrations into a wider frequency range, the perception of noise at a specific frequency is reduced. The periodic frequency change helps to form a specific musical melody, and can further reduce harsh noise and enhance the user's auditory experience, thereby improving the overall comfort and user satisfaction of the electric vehicle while maintaining the heating efficiency of the power battery 13.

[0117] As a possible implementation, the motor controller 12 is used to control the frequency of each phase of the three-phase current to correspond one-to-one with the note frequency of the melody of a song in a preset song library during the process of controlling the periodic change of the frequency of each phase of the three-phase current.

[0118] The motor controller 12 adjusts the frequency of the three-phase current according to the notes in a song in the preset song library, so that the current frequency in each cycle matches the frequency corresponding to the notes in a song in the preset song library.

[0119] In each cycle, the frequency of each phase of the three-phase current will correspond to the frequency of a note of a song in the preset song library. That is, if a note in the song is C4, then in the corresponding cycle, the frequency of each phase of the three-phase current will be set to 261.63 Hz.

[0120] Specifically, the motor controller 12 adjusts the current frequency cycle by cycle according to the order of the notes in the song, so as to form a continuous melody in time. The motor controller 12 first reads a song in the preset song library, each note in the song and its corresponding frequency. In each cycle, the motor controller 12 sets the frequency of each phase of the three-phase current of the drive motor 11 according to the frequency of each note. The motor controller 12 adjusts the frequency of each phase of the three-phase current of the drive motor 11 cycle by cycle according to the order of the notes in the song until the entire song is played.

[0121] In this way, in each changing cycle, the sound generated by the three-phase current on the winding of the drive motor 11 can constitute the melody of a song in the preset song library, thereby converting the noise into a specific song, which can provide users with a unique auditory experience and increase the fun of driving.

[0122] See also Figure 8 As shown, Figure 8Schematic diagram of the direct-axis current signal waveform corresponding to different note combinations. For example, the continuous notes corresponding to a certain sentence of a song are note C4, note D4, note E4, note C4, note C4, note D4, note E4, note C4. Each cycle of the direct-axis current corresponds to a fixed frequency, and within this cycle, the frequency of the direct-axis current signal remains unchanged. As the notes change, the frequency of the direct-axis current signal will also change accordingly, thus forming different waveforms. Figure 8 Shown are waveform diagrams of these frequencies on the time axis, and the waveform within each cycle may be a square wave or other type of waveform, depending on the design and implementation of the motor controller 12.

[0123] In this way, by controlling the frequency of each phase of the three-phase current in multiple consecutive cycles to correspond one-to-one with the frequency of each note of a specific song, the sound generated on the winding of the drive motor 11 can constitute the melody of a song in a preset song library. This method reduces the perception of noise at specific frequencies.

[0124] As a possible implementation, the motor controller 12 is used to control the melody composed of the sound generated by the three-phase current on the winding of the drive motor 11 to switch from one song to another song in a preset song library in response to the user performing a song switching operation.

[0125] See also Fig. 9 As shown, Fig. 9 The waveform diagram is a schematic diagram of the user switching songs. For example, the continuous notes corresponding to a sentence of the first song are notes C4, D4, E4, and C4, and the sounds produced by the three-phase current on the winding of the drive motor 11 are also notes C4, D4, E4, and C4. At this time, the user switches to the second song, and the sounds produced by the three-phase current on the winding of the drive motor 11 are notes F4, C4, B4, and A4.

[0126] In this way, the motor controller 12 responds to the user's song switching operation and switches the sound generated by the winding of the drive motor 11 from the first song to the second song in the preset song library, thereby providing users with a variety of song choices without reducing the heating efficiency, reducing the noise perception of the drive motor when heating the power battery, and significantly improving the user's auditory experience and driving comfort.

[0127] It should be noted that, in order to ensure the heating efficiency, even if the frequency of the direct-axis current signal of each cycle is different, the volt-second product of the direct-axis current signal of each cycle can be the same. Among them, the volt-second product of the signal refers to the integral of the signal, which indicates the accumulation of the signal on the time axis. The volt-second product can also be called the voltage-time integral to describe the cumulative value of the energy or amplitude of the signal over a period of time. The volt-second product of the signal can be expressed in the following integral form: volt-second product = ∫ (signal amplitude) × (time) dt, where the integration is performed from the start time to the end time. The volt-second product can be used to measure the energy consumption or accumulation of the signal over a period of time. For periodic signals, the calculation of the volt-second product can be used to analyze the average energy of the signal. In this way, it can be understood that the amplitude of the direct-axis current signal of each cycle is different, and the duration of the direct-axis current signal of each cycle is also different, so the volt-second product of the direct-axis current signal of each cycle can be made the same, thereby optimizing the heating process of the power battery 13 and ensuring the stability of the heating power of the power battery 13. Continue to refer to Figure 8 As shown, even if the frequency corresponding to the direct-axis current signal of each cycle is different, by adjusting the duration of each cycle, the volt-second product of each cycle is made the same, thereby ensuring the stability of the heating power of the power battery 13.

[0128] As a possible implementation, the motor controller 12 is used to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a first volt-second product in response to the temperature of the power battery 13 being a first temperature, and to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a second volt-second product in response to the temperature of the power battery 13 being a second temperature. The first temperature is lower than the second temperature, and the first volt-second product is greater than the second volt-second product.

[0129] When the temperature of the power battery 13 is low, the motor controller 12 sets the volt-second product of the direct-axis current signal in each cycle to the first volt-second product. A larger volt-second product provides greater heating power for the power battery 13, thereby increasing the battery temperature more quickly.

[0130] When the temperature of the power battery 13 is high, the motor controller 12 sets the volt-second product of the direct-axis current signal in each cycle to the second volt-second product. The smaller volt-second product provides smaller heating power for the power battery 13, thereby avoiding overheating, protecting the power battery 13 and saving energy.

[0131] In low temperature environments, by increasing the volt-second product to provide stronger heating power, the battery temperature can be quickly increased to ensure battery performance and endurance. In high temperature environments, by reducing the volt-second product to reduce heating power, unnecessary energy consumption can be avoided, and overall energy efficiency can be improved. By precisely controlling the heating power, aging and damage of the power battery 13 at excessively high temperatures can be avoided, thereby extending the battery's service life, and the battery can be effectively prevented from overheating, reducing safety risks caused by overheating.

[0132] As a possible implementation, the motor controller 12 is used to control the duration of each cycle of each phase current of the three-phase current to be the same as the duration of each note of a song in a preset song library. This means that the motor controller 12 not only adjusts the frequency of the current to match the frequency corresponding to each note of a song in the song library, but also ensures that the duration of each note in the song is consistent with the duration of the current at the corresponding frequency.

[0133] For example, if the note C4 lasts for 0.5 seconds in the song, the present application can also control each phase of the three-phase current to last for 0.5 seconds at the frequency of C4 (261.63 Hz). This control method ensures that the note corresponding to the vibration of the winding of the drive motor 11 is consistent with the note in the song not only in frequency but also in time, thereby generating a complete and accurate song and making the generated sound more harmonious and pleasant.

[0134] In summary, by controlling the duration of each cycle of each phase current of the three-phase current to be the same as the duration of each note of a song in the preset song library, not only can the noise perception at a specific frequency be effectively reduced, but also the sound generated by the winding on the drive motor 11 can be ensured to be consistent with a song in the preset song library in terms of time and frequency, thereby forming a complete and pleasant melody.

[0135] like Fig.10 As shown, the powertrain provided in the embodiment of the present application includes a heat exchange circuit 15. According to the thermal effect of the current, the three-phase current on the drive motor 11 will cause the three-phase winding of the drive motor 11 to heat up. The powertrain 14 provided in the embodiment of the present application includes a heat exchange circuit 15, and the heat exchange circuit 15 is used to transfer the heat generated on the three-phase winding of the drive motor 11 to the power battery 13 to heat the power battery 13. The powertrain provided in the embodiment of the present application can transfer the heat generated on the winding of the drive motor 11 during the pulse heating process of the power battery to the power battery by setting a heat exchange circuit, thereby improving energy utilization efficiency, saving energy and improving the heating efficiency of the power battery.

[0136] In one embodiment, if Fig.11As shown, the heat exchange circuit 15 includes a heat transfer medium, a heat transfer medium flow circuit, a liquid pump 1101 and a heat exchanger 1102. The heat transfer medium is used to absorb the heat generated on the winding of the drive motor 11, the heat transfer medium flows in the heat transfer medium flow circuit, the liquid pump 1101 is used to provide power for the flow of the heat transfer medium, and the heat exchanger 1102 is used to absorb the heat in the heat transfer medium and conduct the absorbed heat in the heat transfer medium to the power battery 13 to heat the power battery 13.

[0137] Based on the same concept, the present application provides a method for controlling pulse heating of a power battery using music noise reduction, the method comprising: after the user starts the pulse heating function, controlling the midpoint of the bridge arm of the three-phase switch tube bridge arm of the inverter circuit to output a three-phase current to the winding of the drive motor, the three-phase current is used to generate pulse alternating current on the DC bus, the pulse alternating current is used to heat the power battery; controlling the frequency of each phase current of the three-phase current in each cycle to be a set frequency in a set frequency set or 2 times a set frequency in a set frequency set N times, N is an integer, and each set frequency in the set frequency set is the frequency corresponding to a note.

[0138] As a possible implementation, the pulse heating control method also includes, in response to a user selecting a song after starting the pulse heating function, controlling the frequency of each phase of the three-phase current during the changing process to correspond one-to-one with the note frequency of the melody of a song in a preset song library, so that the sound generated by the three-phase current on the winding of the drive motor constitutes the melody of a song in the preset song library.

[0139] As a possible implementation, the pulse heating control method also includes, in response to a user executing a song switching operation, controlling the melody composed of the sound generated by the three-phase current on the winding of the drive motor to switch from one song to another song in a preset song library.

[0140] As a possible implementation, the pulse heating control method further includes controlling the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be the same.

[0141] A person skilled in the art may understand that the various numerical numbers such as first and second involved in the present application are only used for the convenience of description and are not used to limit the scope of the embodiments of the present application. The sequence and order of execution of each process should be determined by its function and internal logic.

[0142] Those skilled in the art will appreciate that the modules of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0143] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A motor controller for realizing pulse heating music noise reduction, characterized in that: The motor controller includes an inverter circuit, which includes a three-phase switch tube bridge arm, and the midpoint of the bridge arm of each phase of the switch tube bridge arm is used to connect a phase winding of the drive motor. The inverter circuit is used to connect the power battery through a DC bus. The motor controller is used to: The midpoint of the bridge arm of the three-phase switch tube bridge arm of the inverter circuit is controlled to output a three-phase current to the winding of the drive motor, the three-phase current is used to generate pulse alternating current on the DC bus, and the pulse alternating current is used to heat the power battery; Control the frequency of each phase current of the three-phase current in each cycle to be one of the set frequencies in the set frequency set or twice the set frequency in the set frequency set N times, where N is an integer.

2. The motor controller according to claim 1, characterized in that: Each set frequency in the set frequency set is a frequency corresponding to a note.

3. The motor controller according to claim 1, characterized in that: The set frequency set includes 12 set frequencies, N is less than or equal to 7, and N is greater than or equal to -7.

4. The motor controller according to claim 1, characterized in that: The motor controller is used to: The frequency of each phase current of the three-phase current is controlled to change periodically and the frequency of each phase current of the three-phase current is controlled to change the same in each change period.

5. The motor controller according to claim 4, characterized in that: The motor controller is used to: In the process of controlling the periodic change of the frequency of each phase current of the three-phase current, the frequency of each phase current of the three-phase current is controlled to correspond one to one with the frequency corresponding to the note of the melody of a song in the preset song library.

6. The motor controller according to claim 4, characterized in that: In each of the variation cycles, the sound generated by the three-phase current on the windings of the drive motor constitutes the melody of a song in a preset song library.

7. The motor controller according to claim 6, characterized in that: The motor controller is used to: In response to the user performing a song switching operation, the melody composed of the sound generated by the three-phase current on the winding of the drive motor is switched from the one song to another song in the preset song library.

8. The motor controller according to claim 1, characterized in that: The motor controller is used to control the frequency difference of each phase current of the three-phase current in any two adjacent cycles to be less than a set frequency threshold.

9. The motor controller according to any one of claims 1 to 8, characterized in that: The motor controller is used to control the frequency of the direct-axis current signal of the three-phase current in each cycle to be any one of a set frequency set, and the type of the direct-axis current signal includes at least one of the following: a sine wave, a triangle wave, and a square wave.

10. The motor controller according to claim 9, characterized in that: The motor controller is used to control the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be the same.

11. The motor controller according to claim 10, characterized in that: The motor controller is used to: In response to the temperature of the power battery being a first temperature, controlling the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a first volt-second product; In response to the temperature of the power battery being a second temperature, controlling the volt-second product of each phase current of the three-phase current in each cycle of the direct-axis current signal to be a second volt-second product; The first temperature is lower than the second temperature, and the first volt-second product is higher than the second volt-second product.

12. A powertrain, characterized in that: The powertrain includes a motor controller and a heat exchange circuit as described in any one of claims 1 to 11, the three-phase current is used to heat the windings of the drive motor, and the heat exchange circuit is used to transfer the heat generated by the windings of the drive motor to the power battery.

13. A method for controlling pulse heating of a power battery using music noise reduction, characterized in that: The pulse heating control method comprises: After the user starts the pulse heating function, the midpoint of the bridge arm of the three-phase switch tube bridge arm of the inverter circuit is controlled to output a three-phase current to the winding of the drive motor, and the three-phase current is used to generate pulse alternating current on the DC bus, and the pulse alternating current is used to heat the power battery; Control the frequency of each phase current of the three-phase current in each cycle to be one of the set frequencies in the set frequency set or twice the set frequency in the set frequency set N times, where N is an integer, and each set frequency in the set frequency set is a frequency corresponding to a note.

14. The method according to claim 13, characterized in that The pulse heating control method further comprises: In response to a user selecting a song after starting the pulse heating function, the frequency of each phase of the three-phase current is controlled to correspond one by one to the note frequency of the melody of a song in the preset song library during the changing process, so that the sound generated by the three-phase current on the winding of the drive motor constitutes the melody of a song in the preset song library.

15. The method according to claim 13, characterized in that The pulse heating control method further comprises: In response to the user performing a song switching operation, the melody composed of the sound generated by the three-phase current on the winding of the drive motor is switched from the one song to another song in the preset song library.

16. The method according to claim 13, characterized in that The pulse heating control method further comprises: The volt-second product of each phase current of the three-phase current is controlled to be the same in each cycle of the direct-axis current signal.

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