WO2023024917A1 - Method for heating power battery of electric vehicle, and electric vehicle - Google Patents

Abstract

A method for heating a power battery of an electric vehicle, comprising: a control module (2110) generates a heating instruction in a battery heating mode, and outputs a driving control signal according to the heating instruction, wherein the heating instruction comprises at least one of a voltage heating instruction and a current heating instruction; a motor driving module (2120) drives a motor (2130) according to the driving control signal, and heats a power battery (2200) in the form of charging and discharging. According to the method, a driving control signal is output by means of an existing control module of an electric vehicle to heat the power battery in the form of charging and discharging, and thus, the power battery is uniformly heated on the basis of the existing power system of the vehicle without increasing the vehicle manufacturing cost; the low-temperature charging time of the vehicle is significantly reduced, and the charging rate of the power battery is improved. Also provided is an electric vehicle.

Description

A kind of electric vehicle power battery heating method and electric vehicle

This application claims priority to a Chinese patent application with application number 202110990695.2 filed with the China Patent Office on August 26, 2021, the entire contents of which are incorporated herein by reference.

technical field

The embodiments of the present application relate to the technical field of electric vehicles, for example, to a method for heating a power battery of an electric vehicle and the electric vehicle.

Background technique

Compared with fuel vehicles, pure electric vehicles and hybrid vehicles have many advantages such as less pollution emissions, low operating noise and high fuel economy. In recent years, pure electric vehicles and hybrid vehicles have been widely promoted and applied.

In pure electric and hybrid vehicle systems, the main power source of the vehicle is the power battery, and the energy of the battery needs to be supplemented by charging. However, when the temperature is low, high-power charging of the battery cannot be realized due to the limitation of the characteristics of the battery itself. Therefore, under low temperature conditions, the battery needs to be preheated first, and high-power charging can only be started when the battery temperature reaches an appropriate temperature. Currently, there are two main heating methods for battery systems, namely internal heating and external heating. Among them, the internal heating method is to directly heat the inside of the battery through the battery resistance or the chemical reaction inside the battery, such as high and low frequency alternating current heating, internal discharge heating of the battery, etc.; the external heating method is to generate heat through an external heating component to heat the battery from the outside. Heating, such as hot air heating, liquid heating, phase change material heating, heating film heating, automotive heater positive temperature coefficient (Positive Temperature Coefficient, PTC) thermistor heating, etc.

For the internal heating method, the temperature rise consistency of this method is poor, and it needs to be equipped with external control circuits or control equipment, which increases the hardware cost of the system; in addition, this method will also have a negative impact on the performance and life of the battery components, posing safety risks. For the external heating method, this method also needs to be equipped with heating components, and the hardware cost is high; at the same time, compared with the internal heating method, the heating time of this method is longer and the heating efficiency is lower.

Contents of the invention

The embodiment of the present application provides a method for heating the power battery of an electric vehicle and an electric vehicle, so as to achieve uniform heating of the power battery without increasing the manufacturing cost of the vehicle, reduce the low-temperature charging time of the whole vehicle, and improve the charging speed and efficiency of the whole vehicle .

In the first aspect, an embodiment of the present application provides a method for heating a power battery of an electric vehicle, wherein the electric vehicle includes an electric drive system and a power battery, the electric drive system includes a control module, a motor drive module, and a motor, and the The power battery is connected to the motor drive module;

The methods include:

The control module generates a heating command in the battery heating mode, and outputs a driving control signal according to the heating command, wherein the heating command includes at least one of a voltage heating command and a current heating command;

The motor driving module drives the motor according to the driving control signal, and heats the power battery in the form of charging and discharging.

In the second aspect, the embodiment of the present application also provides an electric vehicle, including an electric drive system and a power battery, the electric drive system includes a control module, a motor drive module and a motor, and the power battery is connected to the motor drive module;

The control module is configured to generate a heating command in the battery heating mode, and output a driving control signal according to the heating command, wherein the heating command includes at least one of a voltage heating command and a current heating command;

The motor driving module is configured to drive the motor according to the driving control signal, and heat the power battery in the form of charging and discharging.

Description of drawings

Fig. 1 is a flow chart of a method for heating a power battery of an electric vehicle provided in an embodiment of the present application;

Fig. 2 is a schematic structural diagram of a power system of an electric vehicle provided in an embodiment of the present application;

Fig. 3 is a functional block diagram of a power system of an electric vehicle provided by an embodiment of the present application;

Fig. 4 is a schematic structural diagram of a control module of an electric vehicle provided by an embodiment of the present application;

Fig. 5 is a functional block diagram of a current command generation module of an electric vehicle provided by an embodiment of the present application;

FIG. 6 is a functional block diagram of a current command decomposition module of an electric vehicle provided in Embodiment 3 of the present application;

Fig. 7 is a functional block diagram of a voltage command generating module of an electric vehicle provided by an embodiment of the present application;

Fig. 8 is a functional block diagram of a voltage command decomposition module of an electric vehicle provided by an embodiment of the present application;

Fig. 9 is a schematic diagram of the position of the motor rotor for battery heating based on alternating current commands of an electric vehicle provided in Embodiment 3 of the present application under a parking condition;

Fig. 10 is a schematic diagram of the motor rotor position of an electric vehicle heating the battery based on an alternating voltage command under a parking condition provided by an embodiment of the present application.

Detailed ways

The embodiments of the present application will be described in detail below in conjunction with the drawings and embodiments.

Figure 1 is a flow chart of a method for heating a power battery of an electric vehicle provided in Embodiment 1 of the present application. This embodiment can be applied to the power battery heating scene of any device equipped with an electric drive system. This method can be implemented by but not limited to this application The electric vehicle in the example is executed as the execution subject, and the execution subject can be realized by software and/or hardware. As shown in FIG. 2 , an electric vehicle may include an electric drive system 2100 and a power battery 2200 . The electric drive system 2100 includes a control module 2110 , a motor drive module 2120 and a motor 2130 . The power battery 2200 is connected to the motor drive module 2120 . As shown in Figure 1, the method includes the following steps:

Step 110, the control module 2110 generates a heating instruction in the battery heating mode, and outputs a driving control signal according to the heating instruction. Wherein, the heating command includes at least one of a voltage heating command and a current heating command.

The power battery can be any kind of rechargeable battery, which is not limited in this embodiment of the application, for example, it can be a lithium battery, or a nickel-metal hydride battery, or a sodium-sulfur battery, or a lead-acid battery.

The connection link between the power battery and the motor drive module may be an electrical link. The battery heating mode is a type of mode that the electric vehicle is in, which means that the power battery of the electric vehicle needs to be heated in this mode. In addition to the battery heating mode, the electric vehicle can also have a motor output torque mode, that is, a torque mode, and the electrode output torque mode refers to a normal vehicle driving mode.

The type of motor can be permanent magnet synchronous motor (Permanent Magnet Synchronous Motor, PMSM), or can be AC asynchronous motor (AC Asynchronous Motor, ACMC), or can be DC brushless motor (Brushless DC Motor, BLDC), or can be Excitation Motor (EEM).

The control module 2110 may include a motor controller (Motor Control Unit, MCU), and the motor drive module 2120 may include an inverter. In another embodiment, when the main positive relay and the main negative relay of the high-voltage system of the vehicle are both in the closed state, after the high-voltage power-on is completed, the MCU enters the battery under the control of the vehicle control unit (Vehicle Control Unit, VCU). In the heating mode, a heating command is generated, and a driving control signal is output according to the heating command.

The heating command is set to instruct the control module in the battery heating mode to output a driving control signal. The signal type of the heating command can be an analog signal or a digital signal; when the signal type of the heating command is a digital signal, the number system of the heating command can be binary, which is not limited in this embodiment of the present application. The transmission mode of the heating instruction may be wired transmission, or may be wireless transmission.

Step 120 , the motor driving module 2120 drives the motor 2130 according to the driving control signal, and heats the power battery 2200 in the form of charging and discharging.

Wherein, the drive control signal is set to provide a control signal for the motor drive module to drive the motor. The digital system of the driving control signal may be binary, which is not limited in this embodiment of the present application.

In another embodiment, when the main positive relay and the main negative relay of the high-voltage system of the vehicle are both in the closed state, after the high-voltage power-on is completed, the MCU enters the battery heating mode under the control of the VCU, generates a heating command, and according to the heating The instruction outputs the driving control signal. After the MCU completes the fault detection action of the electric drive system and the power battery, when there is no fault in the electric drive system and the power battery, the MCU outputs a drive control signal to drive the motor, and heats the power battery in the form of charging and discharging. When the temperature of the power battery reaches the set threshold, or the electric drive system and/or battery system fails, the vehicle will exit the battery heating mode.

Optionally, the electric vehicle power battery heating method also includes:

Step 130, the control module turns on the battery heating mode when the battery is in a low-temperature state and recognizes that a charging gun is plugged into the vehicle or receives a remote charging reservation request from the user.

Wherein, the specific threshold setting of the low temperature state may be the initial parameter setting of the vehicle system, or may be set independently by the user.

In yet another embodiment, when the battery is in a low-temperature state, and the control module recognizes that the vehicle has a charging gun plugged in or receives a remote charging reservation request from the user, the main positive relay and the main negative relay of the high-voltage system of the vehicle are closed, and the vehicle Complete the high-voltage power-on; under the control of the VCU, the MCU enters the battery heating mode, generates a heating command, and outputs a driving control signal according to the heating command; the MCU completes the fault detection action of the electric drive system and the power battery; when the electric drive system and the power battery When there is no fault, the MCU drives the motor through the driving control signal, and heats the power battery in the form of charging and discharging; when the temperature of the power battery reaches the set threshold, or when the electric drive system and/or battery system fails, the vehicle Exit battery heating mode.

The technical solution of this embodiment adopts the following technical means: in the battery heating mode, the existing control module of the electric vehicle outputs the drive control signal, and the motor drive module drives the vehicle motor according to the drive control signal to heat the power battery in the form of charging and discharging . The above-mentioned technical means overcome the disadvantages of poor heating uniformity, high hardware cost and low heating efficiency of the existing battery heating method, and realize the uniform heating of the power battery based on the existing power system of the whole vehicle without increasing the manufacturing cost of the vehicle. , significantly reducing the low-temperature charging time of the vehicle, and improving the charging speed of the power battery.

Fig. 2 is a schematic structural diagram of a power system of an electric vehicle provided in an embodiment of the present application. As shown in FIG. 2 , the power system of an electric vehicle includes: an electric drive system 2100 and a power battery 2200 , the electric drive system 2100 includes a control module 2110 , a motor drive module 2120 and a motor 2130 , and the power battery 2200 is connected to the motor drive module 2120 .

The control module 2110 is configured to generate a heating command in the battery heating mode, and output a driving control signal according to the heating command, wherein the heating command includes at least one of a voltage heating command and a current heating command. The motor driving module 2120 is configured to drive the motor 2130 according to the driving control signal, and heat the power battery 2200 in the form of charging and discharging.

In one embodiment, the control module 2110 includes: at least one of a current command generation module 2111 and a voltage command generation module 2112 .

The current command generating module 2111 is configured to generate at least one of an alternating d-axis current command and an alternating q-axis current command in the battery heating mode; the voltage command generating module 2112 is configured to generate an alternating d-axis current command in the battery heating mode. at least one of an axis voltage command and an alternating q-axis voltage command. Wherein, the current heating command includes at least one of alternating d-axis current command and alternating q-axis current command, and the voltage heating command includes at least one of alternating d-axis voltage command and alternating q-axis voltage command.

Optionally, the current command generation module 2111 is set to generate an alternating d-axis current command in the battery heating mode, and the q-axis current command is given as 0; the voltage command generation module 2112 is set to generate an alternating current command in the battery heating mode The d-axis voltage command, and the given q-axis voltage command is 0.

Wherein, the current command generation module 2111 can also be set to generate an alternating q-axis current command in the battery heating mode, and set the d-axis current command to be 0; the current command generation module 2111 can also generate an alternating d-axis current at the same time command and alternating q-axis current command.

Correspondingly, the voltage command generating module 2112 can also be set to generate an alternating q-axis voltage command in the battery heating mode, and set the d-axis voltage command to be 0; the voltage command generating module 2112 can also generate an alternating d-axis Voltage command and alternating q-axis voltage command.

The signal types of the alternating d-axis current command, the alternating q-axis current command, the alternating d-axis voltage command and the alternating q-axis voltage command can be analog signals; the transmission modes of the above four alternating commands can be It is wired transmission, or it may be wireless transmission; parameters such as the alternating amplitude, frequency and phase of the above four alternating instructions can be adaptively adjusted according to specific application conditions, which is not limited in the embodiment of the present application.

Optionally, the alternating d-axis current command includes at least one of a current command in the form of a square wave and a current command in the form of a sine wave; the alternating d-axis voltage command includes a voltage command in the form of a square wave and a current command in the form of a sine wave. At least one of the voltage directives.

Wherein, in addition to the current command in the form of a square wave and the current command in the form of a sine wave, the alternating d-axis current command can be any other form of alternating current command, which is not limited in the embodiment of the present application, for example, it can be a triangular wave The current command in the form of a trapezoidal wave, or the current command in the form of a ladder wave.

Correspondingly, in addition to the voltage command in the form of a square wave and the voltage command in the form of a sine wave, the alternating d-axis voltage command may be any other form of alternating voltage command, which is not limited in this embodiment of the present application. For example, it may be The voltage command in the form of a triangular wave may be a voltage command in the form of a trapezoidal wave, or may be a voltage command in the form of a ladder wave.

Adaptive, the alternating q-axis current command can be any form of alternating current command, which is not limited in the embodiment of the present application, for example, it can be a current command in the form of a square wave, or a current command in the form of a sine wave , or may be a current command in the form of a triangular wave, or may be a current command in the form of a trapezoidal wave, or may be a current command in the form of a ladder wave.

Adaptive, the alternating q-axis voltage command can be any form of alternating voltage command, which is not limited in the embodiment of the present application, for example, it can be a voltage command in the form of a square wave, or a voltage command in the form of a sine wave , or may be a voltage command in the form of a triangular wave, or may be a voltage command in the form of a trapezoidal wave, or may be a voltage command in the form of a ladder wave.

In one embodiment, the control module 2110 also includes a torque-current command calculation module 2113, an inverse transformation module 2114, a proportional integral (Proportional Integral, PI) control module 2115, a forward transformation module 2116 and a space vector pulse width modulation ( Space Vector Pulse Width Modulation, SVPWM) module 2117.

The torque-current command calculation module 2113 is configured to convert the torque command value into d-axis current command and q-axis current command in the mode of electrode output torque. The inverse transformation module 2114 is configured to transform the three-phase current of the motor from a stationary coordinate system to a rotating coordinate system to obtain a d-axis current value and a q-axis current value. The PI control module 2115 is configured to receive the difference between the value of the d-axis current command and the d-axis current value, and the difference between the value of the q-axis current command and the q-axis current value, and output the d-axis voltage command and the q-axis voltage command. The forward transformation module 2116 is configured to transform the d-axis voltage command into an Alfa-axis voltage command, and transform the q-axis voltage command into a Beta-axis voltage command. The SVPWM module 2117 is set to calculate and output the pulse width modulation (Pulse Width Modulation, PWM) duty ratio command based on the Alfa axis voltage command and the Beta axis voltage command, and control the power device of the inverter to be turned on and off to drive the motor.

Wherein, the torque command value is used as the input of the torque-current command calculation module 2113, and can be converted into a d-axis current command and a q-axis current command by the torque-current command calculation module 2113; the signal type of the torque command value can be digital The digital system of the signal and the torque command value can be binary, which is not limited in the embodiment of the present application; the torque command value can be generated by the VCU, which is not limited in the embodiment of the present application; the transmission mode of the torque command value It may be wired transmission, or it may be wireless transmission.

The d-axis current command is set to be compared with the d-axis current value; the comparison method between the d-axis current command and the d-axis current value can be subtraction or division, for example, it can be judged by a subtractor, divider or comparator, the embodiment of the present application This is not limited; the signal type of the d-axis current command may be an analog signal; the transmission mode of the d-axis current command may be wired transmission or wireless transmission.

Correspondingly, the q-axis current command is set to be compared with the q-axis current value; the comparison method between the q-axis current command and the q-axis current value can be subtraction or division, for example, it can be judged by a subtractor, divider or comparator. The embodiment of the application does not limit this; the signal type of the q-axis current command may be an analog signal; the transmission mode of the q-axis current command may be wired transmission or wireless transmission.

The signal types of the d-axis current command value, the d-axis current value, the q-axis current command value, and the q-axis current value can be digital signals, and the number system of the above four numerical signals can be binary, which is not the case in this embodiment of the present application. Restrictions; the transmission mode of the above four numerical signals may be wired transmission or wireless transmission.

The d-axis voltage command and the q-axis voltage command are used as the input of the forward transformation module 2116, and can be converted into the Alfa-axis voltage command and the Beta-axis voltage command by the forward transformation module 2116 respectively; the d-axis voltage command, the q-axis voltage command, the Alfa-axis The signal types of the voltage command and the Beta-axis voltage command may be analog signals; the transmission mode of the above four voltage commands may be wired transmission or wireless transmission.

The PWM duty cycle command can be a digital signal, and the number system of the PWM duty cycle command can be binary, which is not limited in the embodiments of the present application; the transmission mode of the PWM duty cycle command can be wired transmission, or can be wireless transmission.

The power device of the inverter can be any type or type of Insulated Gate Bipolar Transistor (IGBT) or Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). The application embodiment does not limit this.

In the above embodiment, in the battery heating mode, the alternating current command obtained by the current command generating module 2111 and the alternating voltage command obtained by the voltage command module, the alternating current command and the alternating voltage command After being processed by the forward transformation module 2116 and the SVPWM module 2117, the motor drive module 2120 drives the motor to run, and charges and discharges the battery to heat the power battery; in the mode of the motor output torque, it is calculated by the torque-current command The current command obtained by the module 2113, the current command is processed by the forward conversion module 2116 and the SVPWM module 2117, and the motor driving module 2120 is used to drive the motor to run, the battery is discharged, the motor continues to output torque, and the electric vehicle is driven to run normally.

In another embodiment, FIG. 3 is a functional block diagram of a power system of an electric vehicle provided in an embodiment of the present application. Referring to FIG. 3 , on the basis of the above technical solution, optionally, the electric vehicle further includes a torque command receiving module 310 , a motor position sensor 320 , a motor position information transmission module 330 and an inverter 340 . The motor position sensor 320 may be a resolver, or may be an incremental encoder, or may be any sensor capable of detecting the position information of the motor rotor. The embodiment of the present application takes the three-phase permanent magnet synchronous motor 2130a as an example for illustration, but does not limit the embodiment of the present application.

In an electric vehicle, after the motor position sensor 320 completes the detection of the motor rotor position θ and the motor speed information ω of the three-phase permanent magnet synchronous motor 2130a, the motor position information transmission module 330 transmits the motor rotor position θ and the motor speed information ω to the forward transform module 2116 and the inverse transform module 2114. The inverse transformation module 2114 completes the coordinate system transformation based on the three-phase currents I _{u_value} , I _{v_value} and I _{w_value} of the three-phase permanent magnet synchronous motor 2130a, and obtains the d-axis current I _{d_value} and the q-axis current I _{q_value} .

In the motor output torque mode, the torque command receiving module 310 receives the torque command Te _cmd sent by the VCU, and sends it to the torque-current command calculation module 2113 . The torque-current command calculation module 2113 converts the value of the torque command Te _cmd into a d-axis current command i _{d_cmd} and a q-axis current command i _{q_cmd} . After the d-axis current command i _{d_cmd} and the q-axis current command i _{q_cmd} are different from the d-axis current value I _{d_value} and the q-axis current value I _{q_value} respectively, the difference is input to the PI control module 2115 . The PI control module 2115 calculates and outputs the d-axis voltage command u _d and the q-axis voltage command u _q . After the d-axis voltage command u _d and the q-axis voltage command u _q undergo the coordinate transformation action of the forward transformation module 2116, the d-axis voltage command u _d is transformed into the Alfa-axis voltage command u _α , and the q-axis voltage command u _q is transformed into Beta Shaft voltage command u _β . After the Alfa-axis voltage command u _α and the Beta-axis voltage command u _β are input to the SVPWM module 2117, after calculation by the SVPWM module 2117, 6-way PWM duty cycle commands are output, and the inverter 340 is controlled based on the 6-way PWM duty cycle commands. The six power devices UT, VT, WT, UB, VB and WB are turned on and off, and then the three-phase permanent magnet synchronous motor 2130a is controlled to output a specified torque.

In the battery heating mode, the current command generating module 2111 can give the alternating d-axis current command i _d * in the form of a current command, and set the q-axis current command to be 0, or can give the alternating d-axis current command in the form of a current command change the q-axis current command i _q *, and set the d-axis current command to be 0; the voltage command generation module 2112 can set the alternating d-axis voltage command u _d * in the form of a voltage command, and set the q-axis voltage The command is 0, or an alternating q-axis voltage command u _q * can be given in the form of a voltage command, and the d-axis voltage command can be given as 0. Therefore, the bus terminal of the inverter 340 can form an alternating charging and discharging current to charge and discharge the battery. The alternating charging and discharging current can realize the heating function of the power battery 2200 under low temperature conditions. In addition, setting the current or voltage command of the d-axis or q-axis to be 0 is to ensure that the three-phase permanent magnet synchronous motor 2130a does not continue to output torque during the heating process of the power battery 2200 during charging and discharging. Therefore, the above-mentioned embodiments of the battery heating mode also meet the working condition that the whole vehicle is in a parked state when the low-temperature battery is heated and charged.

In the technical solution of this embodiment, in the battery heating mode, the alternating current command is obtained through the current command generating module, the alternating voltage command is obtained through the voltage command generating module, and then an alternating current is formed at the bus end of the motor drive module 2120. Charge and discharge current, charge and discharge the power battery, and realize the heating of the battery. This means of heating the power battery under low temperature conditions based on the provision of alternating charge and discharge currents fills in the defects of poor heating uniformity, high hardware cost and low heating efficiency of the existing battery heating method, and realizes the current battery based on the whole vehicle. Some power systems evenly heat the power battery, reduce the cost of automobile manufacturing, significantly reduce the low-temperature charging time of the whole vehicle, and increase the charging speed of the power battery.

FIG. 4 is a schematic structural diagram of a control module of an electric vehicle provided in an embodiment of the present application. This embodiment is refined based on the embodiment shown in FIG. 2 of the present application. As shown in FIG. 4, optionally, the current command generation module 2111 includes a first triangular wave generator module 2111a and a current command decomposition module 2111b. The first triangular wave generator module 2111a is configured to generate an increasing current angle of rotation. The current command decomposition module 2111b is configured to generate at least one of an alternating d-axis current command and an alternating q-axis current command according to the current angle.

The voltage command generation module 2112 includes a second triangle wave generator module 2112a and a voltage command decomposition module 2112b. The second triangular wave generator module 2112a is configured to generate incrementally rotated voltage angles. The voltage command decomposition module 2112b is configured to generate at least one of an alternating d-axis voltage command and an alternating q-axis voltage command according to the voltage angle.

Wherein, the incremental control command of the rotating current angle may be a current frequency command, which is not limited in this embodiment of the present application. The incremental threshold of the rotating current angle may be any electrical angle in the interval [0, 360], for example, 2°, 5° or 10°, which is not limited in this embodiment of the present application.

Correspondingly, the incremental control command of the voltage angle of rotation may be a voltage frequency command, which is not limited in this embodiment of the present application. The incremental threshold of the voltage angle of rotation may be any electrical angle in the interval [0, 360], for example, 2°, 5° or 10°, which is not limited in this embodiment of the present application.

In another embodiment, FIG. 5 is a functional block diagram of a current command generating module of an electric vehicle provided in an embodiment of the present application. Referring to FIG. 5 , on the basis of the above technical solution, optionally, the first triangular wave generator module 2111a generates an incrementally rotating current angle δ ₁ , and the changing frequency of the current angle δ ₁ is controlled by the current frequency command I _freq . At the same time, the frequency of the triangular wave output by the first triangular wave generator module 2111a can also be changed through the adaptive adjustment of the first triangular wave generator module 2111a. Based on the current amplitude command I _amp , the alternating d-axis current command _id * and the alternating q-axis current command i _q * can be obtained by inputting the current angle δ ₁ into the current command decomposition module 2111 b.

In yet another embodiment, FIG. 7 is a functional block diagram of a voltage command generation module of an electric vehicle provided in an embodiment of the present application. Referring to FIG. 7 , on the basis of the above technical solution, optionally, the second triangular wave generator module 2112a generates an incrementally rotating voltage angle δ ₂ , and the changing frequency of the voltage angle δ ₂ is controlled by the voltage frequency command U _freq . At the same time, the frequency of the triangle wave output by the second triangle wave generator module 2112a can also be changed through adaptive adjustment to the second triangle wave generator module 2112a. Based on the voltage amplitude command U _amp , the voltage angle δ ₂ is input to the voltage command decomposition module 2112 b to obtain the alternating d-axis voltage command u _d * and the alternating q-axis voltage command u _q *.

Fig. 6 is a functional block diagram of a current command decomposition module of an electric vehicle provided by an embodiment of the present application. Optionally, the current command decomposition module 2111b includes a first unit cosine wave function generation module 2111b1, a first unit sine wave function generation module 2111b2, a first cosine wave function generation module 2111b3 and a first sine wave function generation module 2111b4.

The first unit cosine wave function generation module 2111b1 calculates the cosine function to obtain the unit d-axis current command. The first unit sine wave function generating module 2111b2 calculates the sine function to obtain the unit q-axis current command. The first cosine wave function generating module 2111b3 is configured to obtain a decomposed d-axis current command according to the unit d-axis current command and the current amplitude command. The first sine wave function generating module 2111b4 is configured to obtain a decomposed q-axis current command according to the unit q-axis current command and the current amplitude command.

Among them, the signal types of the current amplitude command, the unit d-axis current command and the unit q-axis current command can be analog signals, which is not limited in the embodiment of the present application; the transmission mode of the above three commands can be wired transmission, or can be It is wireless transmission.

Adaptively, the first unit cosine wave function generating module 2111b1 can calculate the cosine function to obtain the unit q-axis current command. The first unit sine wave function generation module 2111b2 can calculate the sine function to obtain the unit d-axis current command. The first cosine wave function generation module 2111b3 may be configured to obtain decomposed q-axis current commands according to the unit q-axis current command and the current amplitude command. The first sine wave function generating module 2111b4 may be configured to obtain a decomposed d-axis current command according to the unit d-axis current command and the current amplitude command.

In yet another embodiment, FIG. 6 is a functional block diagram of a current command decomposition module of an electric vehicle provided in an embodiment of the present application.

Referring to Fig. 6, on the basis of the above technical solution, optionally, first, according to the current angle δ ₁ output by the first triangular wave generator module 2111a, the cosine function calculation by the first unit cosine wave function generation module 2111b1 can obtain the unit For the d-axis current command i _{d_unit} *, the unit q-axis current command i _{q_unit} * can be obtained by performing sinusoidal function calculation through the first unit sine wave function generating module 2111b2. Secondly, the decomposed alternating d-axis current command i _d * can be obtained based on the unit d-axis current command i _{d_unit} * and the current amplitude command I _amp through the first cosine wave function generating module 2111b3 , through the first sine wave function The generation module 2111b4 can obtain the decomposed alternating q-axis current command i _q * based on the unit q-axis current command i _{q_unit} * and the current amplitude command I _amp . Finally, the alternating d-axis current command i _d * and the alternating q-axis current command i _q * are transmitted to the back-end equipment, which can realize the heating in the form of charge and discharge of the battery to be recharged. The back-end equipment here can refer to 3 shows the PI control module 2115.

Optionally, the voltage command decomposition module 2112b includes a second unit cosine wave function generation module 2112b1, a second unit sine wave function generation module 2112b2, a second cosine wave function generation module 2112b3 and a second sine wave function generation module 2112b4.

The second unit cosine wave function generation module 2112b1 calculates the cosine function to obtain the unit d-axis voltage command. The second unit sine wave function generation module 2112b2 calculates the sine function to obtain the unit q-axis voltage command. The second cosine wave function generating module 2112b3 is configured to obtain a decomposed d-axis voltage command according to the unit d-axis voltage command and the voltage amplitude command. The second sine wave function generating module 2112b4 is configured to obtain a decomposed q-axis voltage command according to the unit q-axis voltage command and the voltage amplitude command.

Among them, the signal types of the unit d-axis voltage command, the unit q-axis voltage command and the voltage amplitude command may be analog signals, which is not limited in this embodiment of the present application; the transmission methods of the above three commands may be wired transmission, or may be It is wireless transmission.

Adaptively, the second unit cosine wave function generating module 2112b1 can calculate the cosine function to obtain the unit q-axis voltage command. The second unit sine wave function generation module 2112b2 can calculate the sine function to obtain the unit d-axis voltage command. The second cosine wave function generating module 2112b3 may be configured to obtain a decomposed q-axis voltage command according to the unit q-axis voltage command and the voltage amplitude command. The second sine wave function generating module 2112b4 may be configured to obtain a decomposed d-axis voltage command according to the unit d-axis voltage command and the voltage amplitude command.

In yet another embodiment, FIG. 8 is a functional block diagram of a voltage command decomposition module of an electric vehicle provided in an embodiment of the present application.

Referring to Fig. 8, on the basis of the above technical solution, optionally, first, according to the voltage angle δ ₂ output by the second triangular wave generator module 2112a, the cosine function calculation by the second unit cosine wave function generation module 2112b1 can obtain the unit For the d-axis voltage command u _{d_unit} *, the unit q-axis voltage command u _{q_unit} * can be obtained by performing sinusoidal function calculation through the second unit sine wave function generating module 2112b2. Secondly, the decomposed alternating d-axis voltage command u _d * can be obtained based on the unit d-axis voltage command u _{d_unit} * and the voltage amplitude command U _amp through the second cosine wave function generating module 2112b3 , through the second sine wave function The generating module 2112b4 can obtain the decomposed alternating q-axis voltage command u _q * based on the unit q-axis voltage command u _{q_unit} * and the voltage amplitude command U _amp . Finally, the alternating d-axis voltage command u _d * and the alternating q-axis voltage command u _q * are transmitted to the back-end equipment, which can realize the charging and discharging heating of the battery to be recharged. The back-end equipment here can refer to Forward transform module 2116 in FIG. 3 .

In yet another embodiment, FIG. 9 is a schematic diagram of the motor rotor position of an electric vehicle based on an alternating current command for battery heating provided in the embodiment of the present application, and FIG. A schematic diagram of the motor rotor position of an electric vehicle for battery heating based on alternating voltage commands under a parking condition.

9 and 10, on the basis of each of the above technical solutions, optionally, when the alternating current command and/or the alternating voltage command is finally input to the SVPWM module 2117, whether the alternating current command , or alternating voltage commands will form a rotationally changing current or voltage vector. Because the change frequency of the above two vectors is relatively fast, it can usually reach 500-1500Hz. At this frequency, due to the existence of the rotation resistance of the motor itself, the motor will not rotate. Therefore, the rotating current or voltage vector can interact with the stationary motor rotor to form a regular charging and discharging phenomenon, and the battery can be heated based on this regular charging and discharging phenomenon.

In addition, the values of current frequency command I _freq , current amplitude command I _amp , voltage frequency command U _freq and voltage amplitude command U _amp can be selected according to the speed requirement of battery heating and the upper limit of the hardware capability of the motor and motor controller Sure. The larger the amplitude of the excitation waveform, the faster the heating speed of the power battery, but it still needs to meet the requirement that the current value of the motor controller does not exceed the maximum allowable current value. The lower the frequency of the excitation waveform, the faster the heating speed of the power battery, but it also needs to meet the safety requirements of the power battery.

In the technical solution of this embodiment, by setting the first triangular wave generator module, the first unit cosine wave function generation module, the first unit sine wave function generation module, the first cosine wave function generation module and the first sine wave function generation module Capable of generating alternating current commands. In addition, by setting the second triangular wave generator module, the second unit cosine wave function generation module, the second unit sine wave function generation module, the second cosine wave function generation module and the second sine wave function generation module, the alternating voltage command. Based on the above alternating instructions, the bus terminal of the motor drive module forms an alternating charge and discharge current, which heats the power battery under low temperature conditions, which solves the problem of poor heating uniformity in the existing battery heating method. The problem of high hardware cost and low heating efficiency has realized the uniform heating of the power battery based on the existing power system of the whole vehicle, reducing the cost of automobile manufacturing, significantly reducing the low-temperature charging time of the whole vehicle, and improving the charging speed of the power battery.

Claims (11)

1. A method for heating a power battery of an electric vehicle, the electric vehicle includes an electric drive system (2100) and a power battery (2200), and the electric drive system (2100) includes a control module (2110), a motor drive module (2120) and a motor (2130), the power battery (2200) is connected to the motor drive module (2120);

   The methods include:

   The control module (2110) generates a heating command in the battery heating mode, and outputs a driving control signal according to the heating command, wherein the heating command includes at least one of a voltage heating command and a current heating command;

   The motor drive module (2120) drives the motor (2130) according to the drive control signal, and charges and discharges the power battery (2200) to heat the battery.
2. The method according to claim 1, further comprising:

   The control module (2110) turns on the battery heating mode when the battery is in a low-temperature state and recognizes that a charging gun is plugged into the vehicle or receives a user remote charging reservation request.
3. An electric vehicle, comprising an electric drive system (2100) and a power battery (2200), the electric drive system (2100) comprising a control module (2110), a motor drive module (2120) and a motor (2130), the power battery (2200) connecting the motor drive module (2120);

   The control module (2110) is configured to generate a heating command in the battery heating mode, and output a driving control signal according to the heating command, wherein the heating command includes at least one of a voltage heating command and a current heating command;

   The motor driving module (2120) is configured to drive the motor (2130) according to the driving control signal, and charge and discharge the power battery (2200) to heat the battery.
4. The electric vehicle according to claim 3, wherein the control module (2110) comprises: at least one of a current command generation module (2111) and a voltage command generation module (2112);

   The current command generating module (2111) is configured to generate at least one of an alternating d-axis current command and an alternating q-axis current command in battery heating mode;

   The voltage command generation module (2112), configured to generate at least one of an alternating d-axis voltage command and an alternating q-axis voltage command in battery heating mode;

   Wherein, the voltage heating command includes at least one of the alternating d-axis voltage command and the alternating q-axis voltage command; the current heating command includes the alternating d-axis current command and the At least one of alternating q-axis current commands.
5. The electric vehicle according to claim 4, the control module (2110) further comprising:

   The inverse transformation module (2114) is configured to transform the motor three-phase current from a stationary coordinate system into a rotating coordinate system to obtain a d-axis current value and a q-axis current value;

   The PI control module (2115) is configured to receive the difference between the value of the alternating d-axis current command output by the current command generation module (2111) and the d-axis current value output by the inverse transformation module (2114) in the battery heating mode, And the difference between the value of the alternating q-axis current command output by the current command generating module (2111) and the q-axis current value output by the inverse transformation module (2114), outputting the d-axis voltage command and the q-axis voltage command;

   A forward transformation module (2116), configured to transform the d-axis voltage command into an Alfa-axis voltage command, and transform the q-axis voltage command into a Beta-axis voltage command;

   The SVPWM module (2117) is configured to calculate and output a PWM duty cycle command based on the Alfa axis voltage command and the Beta axis voltage command, control the power device of the inverter to be turned on and off, drive the motor to run, and charge and discharge the battery, To heat the power battery.
6. The electric vehicle according to claim 4, the control module (2110) further comprising:

   A torque-current command calculation module (2113), configured to convert the torque command value into a d-axis current command and a q-axis current command in the mode of motor output torque;

   The inverse transformation module (2114) is configured to transform the motor three-phase current from a stationary coordinate system into a rotating coordinate system to obtain a d-axis current value and a q-axis current value;

   The PI control module (2115) is configured to receive the difference between the value of the d-axis current command output by the torque-current command calculation module (2113) and the d-axis current value output by the inverse transformation module (2114), and the torque- The difference between the value of the q-axis current command output by the current command calculation module (2113) and the q-axis current value output by the inverse transformation module (2114), outputs the d-axis voltage command and the q-axis voltage command;

   A forward transformation module (2116), configured to transform the d-axis voltage command into an Alfa-axis voltage command, and transform the q-axis voltage command into a Beta-axis voltage command;

   The SVPWM module (2117) is configured to calculate and output a PWM duty ratio command based on the Alfa axis voltage command and the Beta axis voltage command, control the power device of the inverter to be turned on and off, drive the motor to run and output torque.
7. The electric vehicle according to claim 4, wherein,

   The current command generating module (2111) is configured to generate an alternating d-axis current command in battery heating mode, and set the q-axis current command to be 0;

   The voltage command generating module (2112) is configured to generate an alternating d-axis voltage command in battery heating mode, and set the q-axis voltage command to be 0.
8. The electric vehicle according to claim 7, wherein the d-axis current command includes at least one of a square wave form current command and a sine wave form current command;

   The d-axis voltage command includes at least one of a voltage command in the form of a square wave and a voltage command in the form of a sine wave.
9. The electric vehicle according to claim 4, wherein the current command generation module (2111) comprises:

   a first triangular wave generator module (2111a), configured to generate an increasing current angle of rotation;

   A current command decomposition module (2111b), configured to generate at least one of an alternating d-axis current command and an alternating q-axis current command according to the current angle;

   The voltage command generating module (2112) includes:

   a second triangular wave generator module (2112a), configured to generate incrementally rotated voltage angles;

   A voltage command decomposition module (2112b), configured to generate at least one of an alternating d-axis voltage command and an alternating q-axis voltage command according to the voltage angle.
10. The electric vehicle according to claim 9, wherein the current command decomposition module (2111b) comprises:

    The first unit cosine wave function generation module (2111b1), which calculates the cosine function to obtain the unit d-axis current command,

    The first unit sine wave function generating module (2111b2), which calculates the sine function to obtain the unit q-axis current command,

    The first cosine wave function generating module (2111b3) is configured to obtain a decomposed d-axis current command according to the unit d-axis current command and the current amplitude command;

    The first sine wave function generating module (2111b4) is configured to obtain a decomposed q-axis current command according to the unit q-axis current command and the current amplitude command.
11. The electric vehicle according to claim 9, wherein the voltage command decomposition module (2112b) comprises:

    The second unit cosine wave function generating module (2112b1), which calculates the cosine function to obtain the unit d-axis voltage command,

    The second unit sine wave function generation module (2112b2), which calculates the sine function to obtain the unit q-axis voltage command,

    The second cosine wave function generating module (2112b3) is configured to obtain a decomposed d-axis voltage command according to the unit d-axis voltage command and voltage amplitude command;

    The second sine wave function generating module (2112b4) is configured to obtain a decomposed q-axis voltage command according to the unit q-axis voltage command and voltage amplitude command.

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