Vehicle battery heating method and vehicle battery heating system

Abstract

The invention provides a vehicle battery heating method and a vehicle battery heating system.The method reuses an electric drive system of a vehicle and comprises the steps that target d-axis current and target q-axis current of a motor of the electric drive system are obtained respectively; determining the current d-axis current and the current q-axis current in the current current, collected in real time, of the motor; respectively calculating a d-axis current difference value and a q-axis current difference value based on the target d-axis current, the current d-axis current, the target q-axis current and the current q-axis current; generating a driving signal according to the d-axis current difference value and the q-axis current difference value; and controlling a bridge arm of a multi-phase inverter of the electric drive system to act based on the driving signal so as to form an alternating heating current flowing through the vehicle battery to heat the vehicle battery. The problems that in the prior art, in the vehicle battery heating process, the heating speed is low, the efficiency is low, and heat transfer needs to be achieved through a cooling loop are solved.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle control, and particularly relates to a method for heating a vehicle battery and a heating system for a vehicle battery. Background Art

[0002] In the actual operation scenario of new energy vehicles, the low-temperature environment is likely to cause a significant attenuation of the performance of the vehicle's power battery, which is specifically manifested as problems such as a decrease in output power and a sharp increase in the risk of lithium plating on the anode under the charging condition. This not only leads to an irreversible attenuation of the battery capacity, but also poses serious safety hazards. At present, the industry generally adopts preheating technology to improve the low-temperature battery condition. Among them, the external heating scheme indirectly transfers heat through a heat conduction medium, but there are inherent defects such as large heat conduction loss, low energy efficiency ratio, uneven temperature field distribution, and too long preheating cycle. The existing heating method using the reused electric drive system is to heat the outside of the battery by relying on the heat generated by the motor blocked rotation and transferring heat through the coolant, which has the problems of slow heating speed, low efficiency, and relying on the cooling circuit. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a method for heating a vehicle battery and a heating system for a vehicle battery to solve the problems of slow heating speed, low efficiency, and the need to rely on a cooling circuit to achieve heat transfer during the heating process of the vehicle battery in the prior art.

[0004] To solve or improve the above technical problems to a certain extent, according to one aspect of the present invention, a method for heating a vehicle battery is provided, which reuses the electric drive system of the vehicle. The method includes:

[0005] Obtaining the target d-axis current and the target q-axis current of the motor of the electric drive system respectively;

[0006] Determining the current d-axis current and the current q-axis current in the currently collected current of the motor;

[0007] Calculating the d-axis current difference and the q-axis current difference respectively based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current;

[0008] Generating a driving signal according to the d-axis current difference and the q-axis current difference;

[0009] Controlling the bridge arm action of the multiphase inverter of the electric drive system based on the driving signal to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

[0010] In some embodiments, the corresponding relationship between the heating requirement of the vehicle battery and the d-axis current of the motor of the electric drive system is pre-stored;

[0011] The step of obtaining the target d-axis current of the motor of the electric drive system includes:

[0012] Obtain the real-time heating demand of the vehicle battery;

[0013] Determine the d-axis current corresponding to the real-time heating demand in the corresponding relationship as the target d-axis current.

[0014] In some embodiments, the target d-axis current has a periodic AC component and a DC component, and the absolute value of the amplitude of the DC component is greater than or equal to the absolute value of the amplitude of the AC component.

[0015] In some embodiments, the amplitude of the DC component of the target d-axis current and the amplitude and / or frequency of the AC component change with the change of the real-time heating demand.

[0016] In some embodiments, the target q-axis current is 0.

[0017] In some embodiments, the step of obtaining the target q-axis current of the motor of the electric drive system includes:

[0018] Calculate the position difference between the current position of the rotor of the motor collected in real time and the target position of the rotor;

[0019] Determine the target speed of the motor according to the position difference;

[0020] Calculate the speed difference between the current speed of the rotor of the motor collected in real time and the target speed;

[0021] Determine the target q-axis current based on the speed difference.

[0022] In some embodiments, the target position is the initial position of the rotor when the motor starts running, or the position of the rotor when the rotor can be engaged with an external gear;

[0023] In some embodiments, the heating method of the vehicle battery further includes:

[0024] Adjust the target position to change the target q-axis current.

[0025] In some embodiments, the step of generating a drive signal according to the d-axis current difference and the q-axis current difference includes:

[0026] Respectively determine the q-axis voltage corresponding to the q-axis current difference and the d-axis voltage corresponding to the d-axis current difference;

[0027] Generate the drive signal by using a modulation algorithm based on the q-axis voltage and the d-axis voltage.

[0028] According to an embodiment of the present invention, there is provided a heating system for a vehicle battery, including an electric drive system and a controller of the vehicle, wherein the controller is configured to:

[0029] Obtain a target d-axis current and a target q-axis current of a motor of the electric drive system respectively; determine a current d-axis current and a current q-axis current in a currently collected current of the motor; calculate a d-axis current difference and a q-axis current difference respectively based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current; generate a drive signal according to the d-axis current difference and the q-axis current difference; control the arm movement of a multiphase inverter of the electric drive system based on the drive signal to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

[0030] According to an embodiment of the present invention, there is provided a vehicle including the heating system for a vehicle battery according to any one of the above embodiments.

[0031] According to an embodiment of the present invention, there is provided a controller, which includes a memory and a processor, and the memory stores a computer program, and the program can implement the steps of the heating method for a vehicle battery according to any one of the above embodiments when being executed by the processor.

[0032] According to an embodiment of the present invention, there is provided a computer-readable storage medium for storing a computer program, and the program implements the steps of the heating method for a vehicle battery according to any one of the above embodiments when being executed by a computer or a processor.

[0033] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solutions, the heating method for a vehicle battery and the heating system for a vehicle battery of the present invention can achieve considerable technical progressiveness and practicality, and have wide utilization value in the industry. It has at least the following advantages:

[0034] The heating method of the vehicle battery of the present invention, the heating method of the vehicle battery and the vehicle can directly generate high-frequency current flowing through the internal resistance of the battery during the battery heating process, generate heat inside the battery to directly heat the battery, effectively improve the battery heating efficiency, and do not need to rely on the cooling circuit. At the same time, the current d-axis current of the motor is adjusted in real time by the target d-axis current determined according to the real-time heating demand of the battery, realizing the closed-loop control of battery heating, effectively improving the accuracy of heating control, and the target d-axis current determined according to the real-time heating demand of the battery, adjusting the current amplitude and / or frequency in real time to adapt to the battery heating demand under different working conditions. At the same time, the closed-loop control of the q-axis current avoids the serious NVH problems caused by the low-order pulsating torque existing in the pulse heating of the existing combined electric drive system. The heating system of the vehicle battery of the present invention multiplexes the electric drive system of the vehicle without adding additional hardware configuration.

[0035] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the following specifically gives preferred embodiments and, in conjunction with the drawings, details are described as follows. Brief Description of the Drawings

[0036] Figure 1 It is a topological schematic diagram of the electric drive system of the vehicle according to an embodiment of the present invention;

[0037] Figure 2 It is a flow schematic diagram of the heating method of the vehicle battery according to an embodiment of the present invention;

[0038] Figure 3 It is a waveform schematic diagram of the id-axis current of the motor according to an embodiment of the present invention;

[0039] Figure 4 It is a flow schematic diagram of obtaining the target q-axis current of the motor of the electric drive system according to another embodiment of the present invention;

[0040] Figure 5 It is a heating control block diagram of the heating system of the vehicle battery according to an embodiment of the present invention;

[0041] Figure 6 It is a heating control block diagram of the heating system of the vehicle battery according to another embodiment of the present invention. Detailed Description of the Embodiments

[0042] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in conjunction with the drawings and preferred embodiments, details the specific embodiments and their effects of the heating method of the vehicle battery and the heating system of the vehicle battery proposed according to the present invention as follows.

[0043] An embodiment of the present invention provides a method for heating a vehicle battery, which reuses the electric drive system of the vehicle. The electric drive system of the vehicle includes a multiphase inverter, a multiphase winding, and an energy storage device.

[0044] Among them, the bus of the multiphase inverter is correspondingly connected to the bus of the battery, the multiphase inlets of the multiphase winding are respectively correspondingly connected to the midpoints of the multiphase bridge arms of the multiphase inverter, and the energy storage device is connected in parallel between the bus of the multiphase inverter and the bus of the vehicle battery.

[0045] In one embodiment, as Figure 1 shown, the electric drive system of the vehicle includes: a three-phase inverter, a three-phase winding, and an energy storage capacitor. In this embodiment, the energy storage capacitor serves as the energy storage device.

[0046] Among them, the three-phase inverter, the three-phase winding, and the energy storage capacitor are the inverter, the winding, and the capacitor that reuse the electric drive system of the vehicle. The three-phase inverter includes three-phase bridge arms A, B, and C. Among them, the A-phase bridge arm includes switching devices Q1 and Q2, the B-phase bridge arm includes switching devices Q3 and Q4, and the C-phase bridge arm includes switching devices Q5 and Q6. The three-phase winding includes an A-phase winding LA, a B-phase winding LB, and a C-phase winding LC. The windings LA, LB, and LC of the three-phase winding are respectively correspondingly connected to the midpoints of the A, B, and C three-phase bridge arms of the three-phase inverter through three-phase inlets. The energy storage capacitor is connected in parallel between the bus of the battery and the bus of the three-phase winding.

[0047] Based on the above method for heating a vehicle battery that reuses the electric system of the vehicle, the present invention forms a high-frequency alternating current between the vehicle battery and the energy storage device of the vehicle's electric drive system by controlling the d-axis current of the motor of the vehicle's electric drive system, and uses the thermal effect of the current to heat the vehicle battery.

[0048] As Figure 2 shown, the method for heating a vehicle battery includes:

[0049] Step S10, respectively obtain the target d-axis current and the target q-axis current of the motor of the electric drive system.

[0050] The current of the motor includes a d-axis current and a q-axis current. Among them, the d-axis (i.e., direct-axis) current is used to control the magnitude of the motor magnetic field, and the q-axis (i.e., quadrature axis) current is used to control the magnitude of the torque.

[0051] In this step, the target d-axis current of the motor of the electric drive system can be determined by looking up a table according to the real-time heating requirement of the vehicle battery. Of course, other methods can also be used to determine the target d-axis current of the motor of the electric drive system.

[0052] In one embodiment, the corresponding relationship between the heating requirement of the vehicle battery and the d-axis current of the motor of the electric drive system is pre-stored. During the process of obtaining the target d-axis current of the motor of the electric drive system, first, the real-time heating requirement of the vehicle battery is obtained, and then the d-axis current corresponding to the real-time heating requirement of the vehicle battery is determined from the pre-stored corresponding relationship between the heating requirement of the vehicle battery and the d-axis current of the motor of the electric drive system, and the determined d-axis current is used as the target d-axis current.

[0053] Optionally, the pre-stored corresponding relationship is the corresponding relationship between the heating requirement of the vehicle battery and the amplitude of the d-axis current (including the DC component and the AC component) of the motor of the electric drive system and the frequency of the AC component of the d-axis current (as shown in Table 1). Of course, only some specific embodiments are shown in Table 1, and it is not used to limit all the corresponding relationships between the heating requirement and the d-axis current of the motor of the present invention.

[0054] After determining the real-time heating requirement of the vehicle battery, the d-axis current (including the DC component amplitude, the AC component amplitude, and the AC component frequency) can be determined through the pre-stored corresponding relationship as the target d-axis current.

[0055] Table 1

[0056]

[0057] In some embodiments, the target d-axis current includes a DC component and an AC component, and the DC component and the AC component are periodic, as Figure 3 shown. It should be noted that Figure 3 what is shown in is only a part of the waveform of the target d-axis current, and the target d-axis current may also include other periodic waveforms. Of course, the value of the target d-axis current is not limited to positive values.

[0058] Further, as shown in Table 1, the absolute value of the amplitude of the DC component of the target d-axis current is greater than or equal to the absolute value of the amplitude of the AC component.

[0059] It can be known that during the heating process of the vehicle battery, the real-time heating requirement of the vehicle battery will also change as the heating progresses. Therefore, the target d-axis current determined as the heating progresses will also change accordingly. Based on this, in some embodiments, the amplitude of the DC component of the target d-axis current and the amplitude and / or frequency of the AC component change with the change of the real-time heating requirement.

[0060] In some examples, as shown in Table 1, when the real-time heating demand of the vehicle battery (the heating rate demand of the vehicle battery) is 3 °C / min, the amplitude of the DC component of the d-axis current of the motor is 350 A, the amplitude of the AC component is 300 A, and the frequency of the AC component is 1000 Hz. As the vehicle battery is heated, when the real-time heating demand of the vehicle battery changes to 2 °C / min, the amplitude of the DC component of the d-axis current of the motor is 280 A, the amplitude of the AC component is 260 A, and the frequency of the AC component is 1000 Hz.

[0061] Of course, in the above examples, the frequency of the AC component of the d-axis current of the motor does not change with the change of the real-time heating demand of the vehicle battery. However, in some other actual application scenarios, the frequency of the AC component of the d-axis current of the motor will change with the change of the real-time heating demand of the vehicle battery, and the present invention will not give examples one by one.

[0062] It should be noted that since the q-axis current in the current of the motor is used to control the torque of the motor, when the electric drive system is reused to heat the vehicle battery, it is necessary to control the q-axis current in the current of the motor to avoid the rotation of the rotor of the motor.

[0063] Based on this, in the process of heating the vehicle battery in the present invention, the rotation of the rotor of the motor is avoided by controlling the q-axis current.

[0064] In one embodiment, as Figure 4 shown, the steps of obtaining the target q-axis current of the motor of the electric drive system include:

[0065] Step S100, calculate the position difference between the current position of the rotor of the motor collected in real time and the target position of the rotor.

[0066] In this step, the current position of the rotor of the motor is collected in real time through a position sensor, and then the difference between the current position of the motor rotor and the target position of the motor rotor is calculated to obtain the position difference.

[0067] Among them, the target position of the motor rotor is the initial position of the rotor at the start of motor operation, or the position of the rotor when it can mesh with an external gear.

[0068] Step S102, determine the target speed of the motor according to the position difference.

[0069] In this step, after calculating the position difference between the target position of the motor rotor and the current position of the motor rotor, the position difference is input into the controller, so that the controller outputs the target speed of the motor rotor corresponding to the position difference.

[0070] Step S104, calculate the rotational speed difference between the current rotational speed of the rotor of the motor collected in real time and the target rotational speed.

[0071] In this step, the current rotational speed of the rotor of the motor is collected in real time through a position sensor, and then the difference between the target rotational speed of the motor rotor and the current rotational speed of the motor rotor is calculated as the rotational speed difference.

[0072] Step S106, determine the target q-axis current based on the rotational speed difference.

[0073] In this step, the calculated rotational speed difference is input into the controller, so that the controller outputs the target q-axis current corresponding to the rotational speed difference, that is, the torque generated by the target q-axis current is used to increase or decrease the rotational speed of the motor rotor, and the increased or decreased rotational speed is the rotational speed difference between the target rotational speed and the current rotational speed.

[0074] In one embodiment, the target q-axis current of the motor is 0. In this embodiment, by setting the target q-axis current of the motor to 0, the q-axis current of the motor is controlled to be 0 based on this, so that no torque is generated on the rotor of the motor.

[0075] It can be seen from the above embodiments that the target q-axis current can be determined through the target position and the current position of the motor rotor. Therefore, when the target position of the motor rotor changes, its target q-axis current will definitely change. Based on this, in one embodiment, by adjusting the target position of the motor rotor, the change of the target q-axis current can be realized.

[0076] Specifically, during the process of heating the vehicle battery through the integrated electric drive system, by adjusting the target position of the motor rotor, the target q-axis current can be changed. When the target q-axis current changes, the q-axis voltage will also change, and then the generated second drive signal will also change. After the second drive signal changes, the current position of the motor rotor will also be adjusted.

[0077] When the current position of the motor is adjusted, the distribution of the current will be changed to adjust the heat generation amount of the current on the winding, so as to provide more locked-rotor heat generation amount while meeting the thermal stress of the motor. The heat is externally heated to the battery through the cooling circuit, thereby further improving the heating efficiency of the vehicle battery. Step S20, determine the current d-axis current and current q-axis current in the current current of the motor collected in real time.

[0078] In this step, the current current of the motor is collected in real time through a current sensor, and then the collected current current of the motor is subjected to coordinate transformation to obtain the current d-axis current and current q-axis current of the motor.

[0079] It should be noted that obtaining the d-axis current and q-axis current in the motor current through coordinate transformation is a prior art and will not be elaborated here.

[0080] Step S30: Calculate the d-axis current difference and q-axis current difference based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current respectively.

[0081] In this step, the current target d-axis current is determined according to the real-time heating requirement of the vehicle battery, and the current d-axis current of the motor is detected in real time through a current sensor, and then the difference between the target d-axis current and the current d-axis current is calculated as the d-axis current difference.

[0082] The current target q-axis current is determined according to the above embodiment, and the current q-axis current of the motor is detected in real time through a current sensor, and then the difference between the target q-axis current and the current q-axis current is calculated as the q-axis current difference.

[0083] Step S40: Generate a drive signal according to the d-axis current difference and q-axis current difference.

[0084] In this step, in order to make the current d-axis current of the output current of the motor equal to the target d-axis current to achieve precise control of vehicle battery heating, it is necessary to form a corresponding drive signal according to the difference between the target d-axis current and the current d-axis current to control the arm action of the multiphase inverter of the electric drive system.

[0085] At the same time, in order to avoid the serious NVH (noise, vibration and harshness) problems caused by the low-order pulsating torque in the pulse heating of the reused electric drive system, the difference between the target d-axis current and the current d-axis current and the difference between the target q-axis current and the current q-axis current are jointly used to form a drive signal to control the arm action of the multiphase inverter of the electric drive system.

[0086] In one embodiment, step S40 includes:

[0087] Step 400: Determine the q-axis voltage corresponding to the q-axis current difference and the d-axis voltage corresponding to the d-axis current difference respectively.

[0088] In this step, after calculating the d-axis current difference between the target d-axis current and the current d-axis current, the calculated d-axis current difference is input into the controller so that the controller outputs the d-axis voltage corresponding to the d-axis current difference according to the d-axis current difference.

[0089] After calculating the q-axis current difference between the target q-axis current and the current q-axis current, the calculated q-axis current difference is input into the controller so that the controller outputs the q-axis voltage corresponding to the q-axis current difference according to the q-axis current difference.

[0090] Step 402, generate a drive signal based on the q-axis voltage and the d-axis voltage using a modulation algorithm.

[0091] In this step, after determining the d-axis voltage corresponding to the d-axis current difference and then determining the q-axis voltage corresponding to the q-axis current difference, a drive signal for controlling the arm operation of the multiphase inverter of the electric drive system is generated based on the modulation algorithm.

[0092] Optionally, the modulation algorithm used in this step can be the SVPWM (i.e., Space Vector Pulse Width Modulation) algorithm. Of course, other modulation algorithms can also be used as long as they can achieve modulating the d-axis voltage into a drive signal for controlling the arm operation of the multiphase inverter of the electric drive system.

[0093] Step S50, control the arm operation of the multiphase inverter of the electric drive system based on the drive signal to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

[0094] In this step, after generating the drive signal, the drive signal is used to control the arm operation of the multiphase inverter of the electric drive system to adjust parameters such as the amplitude and frequency amplitude of the current output by the motor to meet the current heating requirement parameters of the vehicle battery.

[0095] After controlling the arm operation of the multiphase inverter of the electric drive system through the drive signal to obtain the current with the parameters required for the current heating requirement of the vehicle battery, the current is input into the vehicle battery to directly heat the inside of the vehicle battery through ohmic heating of the vehicle battery internal resistance.

[0096] Meanwhile, by controlling the arm operation of the multiphase inverter of the electric drive system through the drive signal and controlling the operation of the rotor of the motor, it is possible to avoid the serious NVH problems caused by the low-order pulsating torque in the pulse heating of the reused electric drive system.

[0097] According to another embodiment of the present invention, a heating system for a vehicle battery is provided, and the heating system includes a controller and a reused electric drive system of the vehicle.

[0098] Among them, the electric drive system of the vehicle includes a multiphase inverter, a multiphase winding, and an energy storage device. The bus of the multiphase inverter is correspondingly connected to the bus of the battery, the multiphase incoming ends of the multiphase winding are respectively correspondingly connected to the midpoints of the multiphase arms of the multiphase inverter, and the energy storage device is connected in parallel between the bus of the multiphase inverter and the bus of the vehicle battery.

[0099] The controller is configured to: obtain the target d-axis current and the target q-axis current of the motor of the electric drive system respectively; determine the current d-axis current and the current q-axis current in the currently collected current of the motor; calculate the d-axis current difference and the q-axis current difference respectively based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current; generate a drive signal according to the d-axis current difference and the q-axis current difference; control the arm movement of the multiphase inverter of the electric drive system based on the drive signal to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

[0100] Optionally, the controller includes a PI regulator (proportional integral controller), a PID (Proportion Integration Differentiation) controller, a PD (proportional plus derivative) controller, a PR (Proportion Resonance) controller, or a fuzzy control and other controller structures.

[0101] The specific control methods that can be achieved by the configuration of the controller have been described in detail in multiple embodiments of the above-mentioned heating method for the vehicle battery, and will not be elaborated here.

[0102] Figure 5 The heating control block diagram of the heating system for the vehicle battery according to a specific embodiment of the present invention is shown as Figure 5 As shown, the heating method of the heating system for the vehicle battery includes:

[0103] Step 500, based on the real-time heating demand of the vehicle battery, give the heating current id* (i.e., the target d-axis current) by looking up a table (i.e., the corresponding relationship between the pre-stored real-time heating demand and the d-axis current), and subtract the actual value of id (i.e., the current d-axis current) collected in real time by the current sensor and after coordinate transformation. The difference (i.e., the d-axis current difference) outputs Ud* (i.e., the d-axis voltage) through the controller.

[0104] Step 502: Given iq* (i.e., the target q-axis current) = 0, subtract the actual value of iq (i.e., the current q-axis current) collected in real time by the current sensor and after coordinate transformation. The difference (i.e., the q-axis current difference) outputs Uq* (i.e., the q-axis voltage) through the controller.

[0105] Step 504: Ud* and Uq* generate drive signals through a modulation algorithm (such as SVPWM) to control the switching bridge arm devices of the three-phase inverter, so as to generate an alternating heating current with the target amplitude and / or frequency required for real-time battery heating on the bus between the vehicle battery and the drive system to flow through the battery.

[0106] Figure 6 The heating control block diagram of the heating system of the vehicle battery according to another specific embodiment of the present invention is shown, as Figure 6 shown, the heating method of the heating system of the vehicle battery includes:

[0107] Step 600: The heating current id* (i.e., the target d-axis current) is given by looking up a table (i.e., the pre-stored correspondence between the real-time heating demand and the d-axis current) according to the real-time battery heating demand. By taking the difference between it and the actual value of id (i.e., the current d-axis current) collected in real time by the current sensor and subjected to coordinate transformation, the difference value id_fb (i.e., the d-axis current difference) outputs Ud* (i.e., the d-axis voltage) through the controller.

[0108] Step 602: The position control target θ* (i.e., the target position) of the motor rotor is given, such as the initial value detected during operation or other target values. By taking the difference between it and the actual value of the rotor position θ fb (i.e., the current position), the difference value Δθ (i.e., the position difference) outputs the target value of the motor speed We* (i.e., the target speed) through the controller. By taking the difference between it and the actual value of the motor speed We fb (i.e., the current speed) collected in real time by the position sensor, the difference value ΔWe (i.e., the speed difference) outputs iq* (i.e., the target q-axis current) through the controller.

[0109] Step 604: The obtained iq* is subtracted from the actual value of iq_fb (i.e., the current q-axis current) collected in real time by the current sensor and subjected to coordinate transformation. The difference value (i.e., the q-axis current difference) outputs Uq* (i.e., the q-axis voltage) through the controller.

[0110] Step 606: Ud* and Uq* generate drive signals through a modulation algorithm (such as SVPWM) to control the corresponding switching bridge arm devices of the three-phase inverter to act, so as to generate an alternating heating current with the target amplitude and / or frequency required for real-time battery demand on the bus to flow through the battery.

[0111] According to another embodiment of the present invention, a vehicle is provided, which includes the heating system of the vehicle battery described in any of the above embodiments.

[0112] According to another embodiment of the present invention, a controller is provided, which includes a memory and a processor. The memory stores a computer program, and when the program is executed by the processor, it can implement the steps of the heating method of the vehicle battery in any of the above embodiments.

[0113] According to another embodiment of the present invention, there is provided a readable storage medium for storing a computer program, and the program implements the steps of the vehicle battery heating method in any of the above embodiments when executed by a computer or a processor.

[0114] In the heating method of the vehicle battery of the present invention, the vehicle battery heating method and the vehicle, during the battery heating process, can directly generate high-frequency current flowing through the internal resistance of the battery, generate heat inside the battery to directly heat the battery, effectively improve the battery heating efficiency, and do not need to rely on a cooling circuit. At the same time, the current d-axis current of the motor is adjusted in real time by the target d-axis current determined according to the real-time heating requirement of the battery, realizing the closed-loop control of battery heating, effectively improving the accuracy of heating control, and determining the target d-axis current according to the real-time heating requirement of the battery, and adjusting the current amplitude and / or frequency in real time to adapt to the battery heating requirements under different working conditions. At the same time, the closed-loop control of the q-axis current avoids the serious NVH problems caused by the low-order pulsating torque existing in the pulse heating of the existing combined electric drive system. The vehicle battery heating system of the present invention multiplexes the electric drive system of the vehicle without adding additional hardware configuration.

[0115] The above are only preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A heating method for a vehicle battery, characterized in that, Electric drive system of a reusable vehicle, the method comprising: Obtain the target d-axis current and the target q-axis current of the motor of the electric drive system respectively; Determine the current d-axis current and the current q-axis current in the current current of the motor collected in real time; Calculate the d-axis current difference and the q-axis current difference respectively based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current; Generate a drive signal according to the d-axis current difference and the q-axis current difference; Based on the drive signal, control the arm movement of the multiphase inverter of the electric drive system to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

2. The heating method of the vehicle battery according to claim 1, wherein Pre-select and store the correspondence between the heating requirement of the vehicle battery and the d-axis current of the motor of the electric drive system; The step of obtaining the target d-axis current of the motor of the electric drive system includes: Obtain the real-time heating requirement of the vehicle battery; Determine the d-axis current corresponding to the real-time heating requirement in the correspondence as the target d-axis current.

3. The heating method of the vehicle battery according to claim 1, wherein The target d-axis current has a periodic alternating current component and a direct current component, and the absolute value of the amplitude of the direct current component is greater than or equal to the absolute value of the amplitude of the alternating current component.

4. The heating method of the vehicle battery according to claim 3, wherein The amplitude of the direct current component of the target d-axis current and the amplitude and / or the frequency of the alternating current component change with the change of the real-time heating requirement.

5. The heating method of the vehicle battery according to claim 1, wherein The target q-axis current is 0.

6. The heating method of the vehicle battery according to claim 1, characterized in that, The step of obtaining the target q-axis current of the motor of the electric drive system includes: Calculate the position difference between the current position of the rotor of the motor collected in real time and the target position of the rotor; Determine the target speed of the motor according to the position difference; Calculate the speed difference between the current speed of the rotor of the motor collected in real time and the target speed; Determine the target q-axis current based on the speed difference.

7. The heating method of the vehicle battery according to claim 6, characterized in that, The target position is the initial position of the rotor when the motor starts to operate, or the position of the rotor when the rotor can mesh with an external gear.

8. The heating method of a vehicle battery according to claim 6, characterized in that, It further includes: Adjust the target position to change the target q-axis current.

9. The heating method of the vehicle battery according to any one of claims 1-8, characterized in that, The step of generating a drive signal according to the d-axis current difference and the q-axis current difference includes: Determine the q-axis voltage corresponding to the q-axis current difference and the d-axis voltage corresponding to the d-axis current difference respectively; Generate the drive signal based on the q-axis voltage and the d-axis voltage using a modulation algorithm.

10. A heating system for a vehicle battery, characterized in that, It includes the electric drive system and the controller of the vehicle, wherein the controller is configured to: Obtain the target d-axis current and the target q-axis current of the motor of the electric drive system respectively; determine the current d-axis current and the current q-axis current in the current current of the motor collected in real time; calculate the d-axis current difference and the q-axis current difference respectively based on the target d-axis current and the current d-axis current, and the target q-axis current and the current q-axis current; generate a drive signal according to the d-axis current difference and the q-axis current difference; Based on the drive signal, control the arm movement of the multiphase inverter of the electric drive system to form an alternating current heating current flowing through the vehicle battery to heat the vehicle battery.

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