Battery heating method, device, and storage medium

Abstract

This application discloses a battery heating method, apparatus, and storage medium. When battery heating is required and the motor is stationary, this application enables the application of a current in a specific direction through the two windings of the motor. This cancels out the torques generated by the two windings, keeping the motor stationary, and simultaneously cancels out the magnetic fields generated by the two windings. This allows for an increase in the current amplitude of the two windings without being limited by torque or demagnetization, utilizing the heat loss generated by the increased current to heat the battery. Therefore, this application solves the problem of permanent magnet demagnetization caused by the reverse magnetic field generated by a large current along the d-axis in related technologies, achieving a safe and efficient battery heating effect.

Description

Technical Field

[0001] This application relates to the field of power batteries, and in particular to a battery heating method, device and storage medium. Background Technology

[0002] Lithium-ion batteries are widely used as the power source for electric vehicles due to their high energy density, high power density, and low cost. However, their usable energy and output power decrease significantly at low temperatures, resulting in a substantial reduction in driving range and limiting the promotion of electric vehicles in cold regions. Therefore, effectively heating lithium-ion batteries to improve their low-temperature performance is crucial.

[0003] Currently, lithium-ion batteries are typically heated by utilizing the heat loss of the current in a traditional permanent magnet synchronous motor. The method involves controlling the motor's q-axis current to zero while simultaneously applying a large d-axis current, thereby generating a large current on the DC bus. The heat generated by this current is then used to heat the lithium-ion battery. However, since the d-axis magnetic field direction is aligned with the permanent magnet's magnetic field direction, an excessively large d-axis current can generate a strong reverse magnetic field that directly acts on the permanent magnet, posing a risk of irreversible demagnetization.

[0004] Therefore, how to provide a solution to the above-mentioned technical problems is a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a battery heating method, device, and storage medium to at least solve the problem of permanent magnet demagnetization caused by the reverse magnetic field generated by the large current along the d-axis in the related art, thereby achieving a safe and efficient battery heating effect.

[0006] To address the aforementioned technical problems, this application provides a battery heating method, comprising:

[0007] When the battery needs to be heated, the target heating state of the motor is determined; the motor includes two sets of windings.

[0008] If the target heating state is a static heating state, the current of the two sets of windings is increased so that the combined torque generated by the motor from the two sets of windings is zero, while the heat loss generated by the increased current is used to heat the battery.

[0009] Optionally, increasing the current in both sets of windings includes:

[0010] Determine the maximum allowable current for a single winding of the motor;

[0011] The amplitude of the current in the two sets of windings is increased based on the maximum allowable current.

[0012] Optionally, increasing the magnitude of the current in both sets of windings based on the maximum permissible current includes:

[0013] The d-axis reference current and q-axis reference current of the two sets of windings are determined based on the maximum allowable current, so as to increase the current amplitude of the two sets of windings.

[0014] The amplitude and direction of the d-axis reference current of the two sets of windings are the same, and the amplitude of the q-axis reference current of the two sets of windings is the same but the direction is opposite.

[0015] Optionally, the two sets of windings include a first set of windings and a second set of windings;

[0016] Determining the d-axis reference current and q-axis reference current of the two sets of windings based on the maximum allowable current includes:

[0017] A first target reference current and a second target reference current are determined based on the maximum allowable current, wherein the first target reference current and the second target reference current have the same amplitude but opposite directions;

[0018] In each odd-numbered sub-control cycle of the control cycle when the motor is in the static heating state, the d-axis reference current and q-axis reference current of the first set of windings are controlled to be either the first target reference current or both the second target reference current; the amplitude and phase of the d-axis reference current of the second set of windings are controlled to be the same as those of the d-axis reference current of the first set of windings; and the amplitude of the q-axis reference current of the second set of windings is controlled to be the same as that of the d-axis reference current of the second set of windings, but the phases are opposite.

[0019] In each even-numbered sub-control cycle of the control cycle, the d-axis reference current and q-axis reference current of the second set of windings are controlled to be either the first target reference current or both the second target reference current. The amplitude and direction of the d-axis reference current of the first set of windings and the d-axis reference current of the second set of windings are the same. The amplitude of the q-axis reference current of the first set of windings is the same as that of the d-axis reference current of the first set of windings, but the phases are opposite.

[0020] Each control cycle is divided into multiple consecutive sub-control cycles, and in each control cycle, the d-axis reference current of the first set of windings switches direction at least once.

[0021] Optionally, the two sets of windings include a first set of windings and a second set of windings;

[0022] The battery heating method further includes:

[0023] If the target heating state is a motion heating state, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, so that the motor heats the battery by utilizing the heat loss generated by the superimposed heating current component while outputting the target output torque.

[0024] The two heating current components in the first candidate set are: the first heating current component and the second heating current component, which are opposite in direction.

[0025] Optionally, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, including:

[0026] Determine the d-axis composite reference current and the q-axis composite reference current based on the target output torque;

[0027] A third target reference current is determined based on the d-axis synthesized reference current, and a fourth target reference current is determined based on the q-axis synthesized reference current.

[0028] The d-axis reference current of both sets of windings is controlled to be the third target reference current;

[0029] The q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set;

[0030] Among them, the two superposition results in the second candidate set are: the superposition result of the fourth target reference current and the first heating current component, and the superposition result of the fourth target reference current and the second heating current component.

[0031] Optionally, controlling the q-axis reference current of the first set of windings to be a superposition result of one of the second candidate sets, and controlling the q-axis reference current of the second set of windings to be another superposition result of the second candidate set, includes:

[0032] In each odd-numbered sub-control cycle of the control cycle in which the motor is in the motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component is constant, and the amplitude of the second heating current component is constant.

[0033] During the even-numbered sub-control cycles of each control cycle in which the motor is in the motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component changes continuously with time, and the amplitude of the second heating current component changes continuously with time.

[0034] Each control cycle is divided into multiple consecutive sub-control cycles, and the duration of the odd-numbered sub-control cycles is longer than the duration of the even-numbered sub-control cycles.

[0035] Optionally, the battery heating method further includes:

[0036] Determine the maximum allowable current for a single winding of the motor;

[0037] The first heating current component and the second heating current component are determined based on the maximum allowable current, the d-axis composite reference current, and the q-axis composite reference current.

[0038] This application also provides an electronic device, including:

[0039] Memory, used to store computer programs;

[0040] A processor for executing the computer program to implement the steps of the battery heating method as described in any of the above.

[0041] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the battery heating method as described in any of the above claims.

[0042] As can be seen, this application allows for the heating of the battery when the motor is stationary. By passing a current in a specific direction through the two windings of the motor, the torques generated by the two windings cancel each other out, keeping the motor stationary. Simultaneously, the magnetic fields generated by the two windings also cancel each other out, allowing for an increase in the current amplitude of the two windings without being limited by torque or demagnetization. The heat loss generated by the increased current is then used to heat the battery. Therefore, this application solves the problem of permanent magnet demagnetization caused by the reverse magnetic field generated by a large current along the d-axis in related technologies, achieving a safe and efficient battery heating effect. Attached Figure Description

[0043] To more clearly illustrate the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a flowchart illustrating the steps of a battery heating method provided in an embodiment of this application.

[0045] Figure 2 A topology diagram of a drive system for a dual three-phase permanent magnet synchronous motor provided in an embodiment of this application;

[0046] Figure 3 This is a control block diagram of a dual three-phase permanent magnet synchronous motor battery provided in an embodiment of this application;

[0047] Figure 4 This application provides a d-axis reference current waveform diagram of two sets of windings under static heating conditions, as shown in the embodiments of this application.

[0048] Figure 5 This application provides a q-axis reference current waveform diagram of two sets of windings under static heating conditions, as shown in the embodiments of this application.

[0049] Figure 6 This application provides a d-axis reference current waveform diagram of two sets of windings under motion heating state, as shown in an embodiment of the present application.

[0050] Figure 7 This application provides a q-axis reference current waveform diagram of two sets of windings under motion heating state, as shown in an embodiment of the present application.

[0051] Figure 8 This is a flowchart illustrating the steps of another battery heating method provided in an embodiment of this application. Detailed Implementation

[0052] The core of this application is to provide a battery heating method, device, and storage medium to at least solve the problem of permanent magnet demagnetization caused by the reverse magnetic field generated by the large current along the d-axis in related technologies, thereby achieving a safe and efficient battery heating effect.

[0053] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0054] Please refer to Figure 1 This application provides a battery heating method, including:

[0055] S101: When the battery needs to be heated, determine the target heating state of the motor; the motor includes two sets of windings.

[0056] The battery can be a lithium-ion battery, a lead-acid battery, or other types of batteries whose performance deteriorates at low temperatures. This embodiment does not specifically limit the conductive elements of the battery. This embodiment is applicable to various devices that include motor-battery coupling systems, including but not limited to electric vehicles, electric ships, industrial mobile robots, and mobile energy storage power systems.

[0057] Before performing this step, it is first determined whether the battery needs to be heated. The determination criteria include, but are not limited to, any one or a combination of the following: whether a heating command has been received from the user, whether the ambient temperature of the battery is below a preset first temperature threshold, etc. If any one or a combination of the above conditions is met, it is determined that the battery needs to be heated; otherwise, it is determined that the battery does not need to be heated, the process ends, and normal motor control mode is entered, such as MTPA (Maximum Torque Per Ampere) mode. The first temperature threshold refers to the critical temperature at which battery performance begins to significantly decline. The specific value can be calibrated according to the battery's chemical system (such as lithium-ion batteries, lead-acid batteries, etc.), and this embodiment does not impose a specific limitation.

[0058] It is understood that this embodiment heats the battery by controlling the heat loss generated by the motor. The motor in this embodiment is a motor with two sets of windings, such as a zero-phase-shift dual three-phase permanent magnet synchronous motor. The drive system topology of the dual three-phase permanent magnet synchronous motor in this embodiment is referenced. Figure 2 As shown, the two windings (ABC and DEF) are controlled by two independent voltage source inverters, and the DC bus voltage input to the two voltage source inverters is the same. (Refer to...) Figure 3 As shown, Figure 3 This paper presents a control block diagram for a battery in a dual three-phase permanent magnet synchronous motor. During normal operation, the motor operates in a dual dq model vector control mode, requiring a total of four current proportional-integral controllers. The calculated stator voltages of the two windings are used to calculate the duty cycle through a zero-sequence voltage injection SPWM waveform generation method, and then the motor is controlled accordingly. Figure 2 Turning on the power devices of the two inverters. Under normal conditions, the reference current amplitudes of the two windings are the same, both being the values ​​output from the field weakening outer loop and the torque lookup table. When the motor operates in the corresponding heating state, the reference current of the two windings will be redistributed.

[0059] The following sections explain how to redistribute the reference current of the two windings when the motor is operating in different heating states.

[0060] Specifically, based on the operating conditions of different application devices, the target heating state of the motor can be configured into multiple modes, mainly including a static heating state and a dynamic heating state. The control strategies for the two windings differ under different heating states. Therefore, when it is determined that the battery needs heating, the target heating state of the motor needs to be further determined. The target heating state of the motor is one of a static heating state or a dynamic heating state. The static heating state refers to the condition where the motor maintains zero speed or basically does not produce mechanical rotational output. By controlling the electrical parameters of the two windings, electrical energy is mainly converted into heat dissipation of the windings themselves, thereby generating heat to heat the battery. The dynamic heating state refers to the condition where the motor is rotating. While meeting the drive power requirements of the load, the current of the two windings is controlled in a coordinated manner to generate controllable heat loss on top of the output torque, thus achieving a heating state where drive and heating occur simultaneously.

[0061] As an optional embodiment, after determining that the battery needs to be heated, the target heating state for the motor can be determined based on the current operating conditions of the application scenario. Specifically, if the application device has no power output requirements (i.e., it is in pure standby or charging state), all electrical energy can be converted into heat energy to achieve rapid temperature rise, and the static heating state should be selected. Conversely, if the application device has power output requirements (for example, an electric vehicle needs to be driven, or it needs to supply power to on-board loads such as air conditioners when parked; or, for example, an energy storage system needs to discharge to the grid or load), other heating methods (such as motion heating) can be selected according to the actual operating conditions. This embodiment does not specifically limit this.

[0062] Taking electric vehicles as an example, once it is determined that the battery needs heating, the current state information of the vehicle can be used to determine whether there is a power output requirement in the application scenario where the battery is located. The current state information includes not only vehicle speed, gear position, and accelerator pedal opening related to driving, but also air conditioning switch and hydraulic system status related to parking load. If the vehicle is completely powered off and stationary or only connected to a slow charger, it is determined that there is no power output requirement, and a stationary heating state is selected as the target heating state. If the vehicle is in motion or has a continuous power output requirement, the target heating state can be determined as a moving heating state. Of course, the above is only an example; how to determine the target heating state can be set according to actual engineering needs, and this embodiment does not impose specific limitations here.

[0063] S102: If the target heating state is a static heating state, increase the current of the two sets of windings so that the combined torque generated by the motor in the two sets of windings is zero, and use the heat loss generated by the increased current to heat the battery.

[0064] In this embodiment, if the target heating state is determined to be a static heating state, the battery needs to be heated by the self-heating of the windings without the motor generating torque output. To this end, this embodiment increases the current flowing through both sets of windings to increase the copper losses in the windings, thereby generating more heat. Considering that directly increasing the current would generate torque, causing the motor to rotate unexpectedly, this embodiment, while controlling the increase of the current in both sets of windings, distributes the current amplitude and phase of the two sets of windings so that the torques generated by the two sets of windings cancel each other out, i.e., the combined torque is zero. Specifically, for a motor containing two sets of symmetrical windings (such as a zero-phase-shift dual three-phase motor), currents with equal amplitudes and phase differences of a specific angle can be flowed into the two sets of windings to cancel out their rotating magnetomotive forces, thus making the stator's combined magnetic field zero. In this way, the interaction between the stator magnetic field and the rotor permanent magnet magnetic field disappears, the motor cannot output torque, and the rotor remains stationary.

[0065] Meanwhile, the elimination of the combined magnetic field also avoids the risk of demagnetization of the rotor permanent magnets by the stator current. During normal operation, excessive stator current can generate a strong magnetic field, which, if its direction is opposite to the permanent magnet's magnetic field, can lead to irreversible demagnetization. However, under the control strategy of this embodiment, the magnetic fields of the two windings cancel each other out, resulting in a near-zero combined stator magnetic field, thus reducing the risk of demagnetization. The increased current generates significant copper losses in the windings (heat loss is proportional to the square of the current), while iron losses are relatively small due to magnetic field cancellation; the main heat source is the winding copper losses. The increased current generates heat in the windings, which is transferred to the battery through a water-cooling circuit, achieving efficient heating.

[0066] It should be noted that the degree of current increase needs to consider the current-carrying capacity of the winding conductors, the output capacity of the inverter, and the heating power requirements. Flexible control of the heating power can be achieved by adjusting the current command in real time. Furthermore, to ensure that the combined torque is zero, as an optional implementation, a closed-loop control strategy can be adopted to monitor the motor speed or rotor position in real time and fine-tune the current distribution between the two sets of windings to ensure that the rotor remains stationary.

[0067] In an exemplary embodiment, increasing the current in the two sets of windings includes:

[0068] Determine the maximum allowable current for a single winding of the motor;

[0069] The current amplitude of the two windings is increased based on the maximum allowable current.

[0070] In this embodiment, the maximum allowable current Ismax for a single winding is first determined. This maximum allowable current Ismax is a current threshold calibrated through experiments or simulations, representing the maximum current value that the winding can withstand while ensuring the safe operation of the motor and drive system. Using this maximum allowable current Ismax as a reference for increasing the current allows the winding to generate as much heat as possible per unit time, thereby maximizing the heating power, meeting the need for rapid battery temperature increase, and improving heating efficiency.

[0071] Of course, besides directly using a constant maximum allowable current Ismax to increase the current amplitude of the two windings, other methods can be used to flexibly control the current to adapt to different heating scenarios and system constraints. For example, in the initial stage of heating, to avoid the impact of sudden current changes on the system, a step-like or ramp function approach can be used to gradually increase the current to the target value. The choice can be made according to the actual engineering needs, and this embodiment does not impose specific limitations here.

[0072] In one exemplary embodiment, increasing the magnitude of the current in both windings based on the maximum permissible current includes:

[0073] The d-axis reference current and q-axis reference current of the two windings are determined based on the maximum allowable current in order to increase the current amplitude of the two windings.

[0074] The amplitude and direction of the d-axis reference current of the two windings are the same, and the amplitude of the q-axis reference current of the two windings are the same but the directions are opposite.

[0075] In this embodiment, the d-axis and q-axis reference currents of the two windings are determined based on the maximum allowable current Ismax. Specifically, to achieve a static heating state where the combined torque is zero and the magnetic fields cancel each other out, the current vectors of the two windings need to be precisely allocated. The amplitude and direction of the d-axis reference currents of the two windings are the same, and can be set as follows: Alternatively, it can be set to ,in, This is the d-axis reference current for the first winding. This is the d-axis reference current for the second winding; simultaneously, the q-axis reference currents for both windings have the same amplitude but opposite directions, meaning the q-axis reference current for the first winding is... The q-axis reference current of the second winding is Or the q-axis reference current of the first winding is The q-axis reference current of the second winding .

[0076] It is understandable that the electromagnetic torque of the motor is mainly provided by the q-axis current. By making the magnitudes of the q-axis reference currents of the two windings equal and their directions opposite, the torque components they generate cancel each other out, resulting in a total resultant torque of zero. This ensures that the rotor remains stationary and prevents accidental rotation without relying on a mechanical brake. The d-axis current mainly affects the motor's magnetic field. When d-axis reference currents of the same magnitude and direction are applied to the two windings, the d-axis magnetomotive forces generated by the two windings are superimposed. However, due to the spatial symmetry of the two windings and the phase relationship of the injected currents, the stator's resultant magnetic field cancels each other out, thus eliminating the risk of demagnetizing the rotor's permanent magnets.

[0077] The formula for calculating the magnitude of the current vector is as follows. It can be seen that when and All At this time, the magnitude of the synthesized current vector is Ismax, thereby maximizing the utilization of the winding current while meeting the safety constraints of the motor and inverter, optimizing the heating power of the winding, and thus improving the battery heating efficiency.

[0078] Furthermore, this embodiment achieves torque cancellation by setting the q-axis reference currents of the two sets of windings to be in opposite directions, thereby keeping the motor stationary without the need for a mechanical brake, simplifying the system structure and reducing costs. Besides the aforementioned distribution method of applying both d-axis and q-axis currents simultaneously, in other optional embodiments, if the motor shaft is already fixed and rotation is prevented by other means (such as a mechanical brake), heating can also be achieved by setting only the d-axis reference current (making the d-axis currents of the two sets of windings in the same direction and with equal amplitude) or only the q-axis reference current (making the q-axis currents of the two sets of windings in opposite directions and with equal amplitude). For example, when only the d-axis current is applied, the windings will still generate heat, and since the d-axis current does not generate torque (for surface-mounted permanent magnet synchronous motors) or the generated reluctance torque can be overcome by the mechanical brake, stationary heating can also be achieved; when only the q-axis currents in opposite directions are applied, although theoretically pulsating torque will be generated, the rotor is fixed under mechanical brake locking, and the current can still increase to generate heat. The current distribution method can be selected according to actual engineering needs, and this embodiment does not impose specific limitations.

[0079] In one exemplary embodiment, the two sets of windings include a first set of windings and a second set of windings;

[0080] The d-axis reference current and q-axis reference current of the two windings are determined based on the maximum allowable current, including:

[0081] The first target reference current and the second target reference current are determined based on the maximum allowable current. The first target reference current and the second target reference current have the same amplitude but opposite directions.

[0082] In each odd-numbered sub-control cycle of each control cycle when the motor is in a static heating state, the d-axis reference current and q-axis reference current of the first set of windings are both the first target reference current or both the second target reference current. The amplitude and phase of the d-axis reference current of the second set of windings are the same as those of the d-axis reference current of the first set of windings. The amplitude of the q-axis reference current of the second set of windings is the same as that of the d-axis reference current of the second set of windings, but the phases are opposite.

[0083] In the even-numbered sub-control cycles of each control cycle, the d-axis reference current and q-axis reference current of the second set of windings are both the first target reference current or both the second target reference current. The amplitude and direction of the d-axis reference current of the first set of windings and the d-axis reference current of the second set of windings are the same. The amplitude of the q-axis reference current of the first set of windings is the same as that of the d-axis reference current of the first set of windings, but the phases are opposite.

[0084] Each control cycle is divided into multiple consecutive sub-control cycles. In each control cycle, the d-axis reference current of the first set of windings switches direction at least once.

[0085] In this embodiment, the first target reference current is The second target reference current is .

[0086] When the motor is in a stationary heating state, its operating state can change periodically, and the frequency corresponding to the control period T can be set to be less than the motor's switching frequency. If the motor switching frequency is 2kHz, then the control period T should be converted to a frequency of less than 200Hz, i.e. This embodiment divides the control cycle T into multiple consecutive sub-control cycles. The durations of these sub-control cycles can be the same or different; this embodiment uses a scheme where all sub-control cycles have the same duration. This is because periodic changes in the motor can increase the iron losses caused by magnetic saturation, which can also generate heat. The number of sub-control cycles can be set according to actual engineering needs; this embodiment does not impose a specific limitation.

[0087] Since the control cycle is divided into multiple consecutive sub-control cycles, there are odd-numbered sub-control cycles and even-numbered sub-control cycles. For example, suppose the control cycle is divided into a first sub-control cycle, a second sub-control cycle, a third sub-control cycle, and a fourth sub-control cycle, where the first and third sub-control cycles are odd-numbered sub-control cycles, and the second and fourth sub-control cycles are even-numbered sub-control cycles.

[0088] During odd-numbered control cycles, the d-axis reference current and q-axis reference current of the first set of windings have the same amplitude and the same direction. The q-axis reference current of the second set of windings has the same amplitude and the opposite direction to the d-axis reference current of the second set of windings. Under this distribution method, the first set of windings operates in a high-heat state, the second set of windings operates in a low-heat state, and the q-axis currents of the two sets of windings are always equal in magnitude and opposite in direction, ensuring that the combined torque is zero and the rotor remains stationary.

[0089] for example At this point, since the d-axis reference current of the second winding and the d-axis reference current of the first winding have the same amplitude and direction, therefore, Since the q-axis reference current of the second winding and the q-axis reference current of the first winding have the same amplitude and opposite directions, then... That is, the q-axis reference current of the second winding and the d-axis reference current of the second winding have the same amplitude but opposite directions; for example... At this point, since the d-axis reference current of the second winding and the d-axis reference current of the first winding have the same amplitude and direction, therefore, Since the q-axis reference current of the second winding and the q-axis reference current of the first winding have the same amplitude and opposite directions, then... .

[0090] During even-numbered control cycles, the d-axis reference current and q-axis reference current of the second set of windings have the same amplitude and direction, while the q-axis reference current of the first set of windings has the same amplitude and opposite direction to the d-axis reference current of the second set of windings. Under this distribution method, the second set of windings operates in a high-heat state, the first set of windings operates in a low-heat state, and the q-axis currents of the two sets of windings are always equal in magnitude and opposite in direction, ensuring that the combined torque is zero and the rotor remains stationary.

[0091] for example At this point, since the d-axis reference current of the second winding and the d-axis reference current of the first winding have the same amplitude and direction, therefore, Since the q-axis reference current of the second winding and the q-axis reference current of the first winding have the same amplitude and opposite directions, then... For example, At this point, since the d-axis reference current of the second winding and the d-axis reference current of the first winding have the same amplitude and direction, therefore, Since the q-axis reference current of the second winding and the q-axis reference current of the first winding have the same amplitude and opposite directions, then... .

[0092] As an optional implementation, the control period T can be divided into four sub-control periods. (Refer to...) Figure 4and Figure 5 As shown:

[0093] exist During this period, the d-axis reference current and q-axis reference current of the first winding are both The d-axis reference current of the second winding is The q-axis reference current of the second winding is ;

[0094] exist During this period, the d-axis reference current of the first winding is The q-axis reference current of the first winding is The d-axis reference current and q-axis reference current of the second winding are both ;

[0095] exist During this period, the d-axis and q-axis reference currents of the first winding were both The d-axis reference current of the second winding is The q-axis reference current of the second winding is ;

[0096] exist During this period, the d-axis reference current of the first winding is The q-axis reference current of the first winding is The d-axis reference current and q-axis reference current of the second winding are both .

[0097] This embodiment alternates the current distribution mode of the two windings between odd-numbered and even-numbered control cycles. This allows the first and second windings to alternately handle high-heat and low-heat states within a complete control cycle, ensuring that the average heat generation of the two windings is consistent over a complete control cycle T. This prevents one winding from overheating due to prolonged high current, achieving a balanced distribution of thermal stress and improving the insulation life of the motor and the long-term reliability of the system. Regardless of the current distribution mode switching, the q-axis current of the two windings remains equal in magnitude and opposite in direction, ensuring that the total combined torque of the motor is always zero, thus eliminating the need for mechanical braking to keep the rotor stationary. Furthermore, this operation of switching the current distribution mode between odd and even-numbered control cycles causes a high-frequency alternation of the magnetic field direction in the motor core, generating additional hysteresis and eddy current losses (i.e., iron losses) in the stator core. These iron losses are also converted into heat energy, which, combined with the copper losses of the windings themselves, further increases the total heating power of the motor without increasing the current amplitude, thus improving the heating efficiency of the battery. By setting the frequency of the control cycle appropriately, the iron core can be made to operate in a region with a large hysteresis loop area, maximizing the use of the additional heat generated by the magnetic saturation effect.

[0098] Furthermore, considering that some related technologies attempt to heat the windings and prevent the motor from rotating by alternately applying opposite voltage vectors to the motor within a short period of time, utilizing the difference between mechanical inertia and electrical time constant, this open-loop control method requires extensive experimental calibration of the voltage vector's application time for different motor parameters and operating conditions. This cumbersome debugging process makes it difficult to guarantee universality. The solution adopted in this embodiment precisely distributes the current vectors of the two windings, ensuring that the q-axis currents of the two windings are equal in magnitude and opposite in direction. This ensures that the electromagnetic torques cancel each other out, resulting in a constant total torque of zero, thus preventing the motor from rotating. Simultaneously, this embodiment sets the d-axis and q-axis reference currents based on the maximum allowable current and introduces real-time feedback control. It can adaptively maintain a stationary state without relying on offline calibration and maximizes the utilization of the winding current, improving heating efficiency.

[0099] It's understandable that after heating the battery for a period of time using a stationary motor, the battery's operating temperature will gradually rise. When the battery's operating temperature rises to the second temperature threshold, it indicates that the battery has recovered to a condition where it can perform normally. At this point, different processing methods can be selected based on actual application needs: If the application equipment where the motor is located does not need to operate, the stationary heating state can continue to heat the battery until the battery's operating temperature rises to the third temperature threshold (the third temperature threshold is greater than the second temperature threshold), and then the stationary heating state can be exited, entering the motor's normal control mode, such as MTPA mode; if the application equipment where the motor is located needs to operate normally at this time, it is no longer necessary to keep the motor stationary, and the motor can be controlled to enter a dynamic heating state, continuing to heat the battery while the motor rotates and outputs torque, thus balancing the application equipment's operation and the battery's heating needs.

[0100] Taking electric vehicles as an example, after the battery is heated for a period of time by the motor in a stationary heating state, the battery's operating temperature gradually rises. When the battery's operating temperature rises to the second temperature threshold, a prompt message is generated to inform the user that the battery has been preheated to a temperature range that supports vehicle operation. The user can choose whether to start the vehicle based on this prompt message. If the user chooses to start the vehicle (e.g., through power-on operation or inputting a driving command), it indicates that there is a driving demand. The vehicle controller responds to this command by controlling the motor to enter a motion heating state, continuing to heat the battery while meeting the drive power requirements until the battery's operating temperature rises to the third temperature threshold. If the user does not choose to start the vehicle (i.e., the vehicle remains parked), the vehicle controller maintains the motor's stationary heating state, continuing to heat the battery through pure heat generation until the battery's operating temperature rises to the third temperature threshold. Once the battery's operating temperature rises to the third temperature threshold, the motor exits the above heating state and enters the motor's normal control mode (such as MTPA mode).

[0101] The following is a detailed explanation of the motor's heating state during operation. In this state, the combined torque of the two windings is the target output torque required for the application scenario. Each winding generates an additional torque in the opposite direction to increase the current amplitude and generate heat.

[0102] In one exemplary embodiment, the two sets of windings include a first set of windings and a second set of windings;

[0103] Battery heating methods also include:

[0104] If the target heating state is a motion heating state, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, so that the motor can heat the battery by utilizing the heat loss generated by the superimposed heating current component while outputting the target output torque.

[0105] The two thermocurrent components in the first candidate set are the first thermocurrent component and the second thermocurrent component, which are opposite in direction.

[0106] In this embodiment, after determining that the target heating state of the motor is a motion heating state, the target output torque is first determined. The target output torque is the target torque value that the motor needs to output, calculated based on the operating conditions of the application scenario (such as equipment operation commands, external load changes, etc.). After determining the target output torque, a first initial current can be allocated to the first set of windings and a second initial current can be allocated to the second set of windings based on table lookup or real-time calculation. The allocation of the first initial current and the second initial current must satisfy that the combined torque generated by their combined action is equal to the target required torque, and the allocation can be based on the optimal system efficiency, for example, following the maximum torque-to-current ratio (MTPA) control or maximum efficiency control strategy.

[0107] Based on this, to achieve battery heating during operation, additional heating current components need to be superimposed on the initial current. Specifically, a first heating current component is superimposed on the first winding, and a second heating current component is superimposed on the second winding, or a second heating current component is superimposed on the first winding, and a first heating current component is superimposed on the second winding. The first and second heating current components are in opposite directions. It can be understood that the torque generated in the motor air gap by the oppositely oriented heating current components cancels each other out. Therefore, the superposition will not change the original total output torque of the motor; the target output torque is still guaranteed by the interaction of the first and second initial currents. Simultaneously, the superimposed current components will generate additional heat on the winding resistance. This heat is transferred to the battery through water cooling, achieving the effect of heating while driving.

[0108] As an optional embodiment, the superposition of the above-mentioned heating current components can be implemented in various ways within the vector control framework. For example, the heating current components can be injected into the d-axis direction. In this case, the superimposed current mainly affects the motor magnetic field without directly generating torque, while generating heat. Alternatively, they can be injected into the q-axis direction. In this case, the heating current components of the two windings are opposite in direction and equal in magnitude on the q-axis, and the torques they generate cancel each other out, thus not affecting the total output torque.

[0109] As an optional embodiment, this embodiment can pre-establish a first candidate set based on the first and second heating current components with opposite directions. This set can contain multiple pairs of heating current components with different amplitudes to adapt to different heating power requirements. During the motion heating process, the controller can select a suitable heating current component from the first candidate set for superposition based on the current operating conditions (such as battery temperature, heating requirements, system voltage, inverter current margin, motor thermal state, etc.). Specifically, the first heating current component from the first candidate set can be superimposed on the current allocated to the first winding based on the target output torque, and the second heating current component from the first candidate set can be superimposed on the current allocated to the second winding; or the superposition method can be interchanged, that is, the second heating current component can be superimposed on the first winding, and the first heating current component can be superimposed on the second winding. Both superposition methods can achieve the same heating effect and do not affect the total torque output.

[0110] In this way, this embodiment achieves flexible adjustment of heating power while meeting the target output requirements, thus balancing the power output requirements of the application scenario with the maintenance of the battery's low-temperature performance.

[0111] In one exemplary embodiment, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, including:

[0112] Determine the d-axis composite reference current and the q-axis composite reference current based on the target output torque;

[0113] The third target reference current is determined based on the d-axis synthesized reference current, and the fourth target reference current is determined based on the q-axis synthesized reference current.

[0114] The d-axis reference current of both sets of windings is controlled to be the third target reference current;

[0115] The q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set;

[0116] Among them, the two superposition results in the second candidate set are: the superposition result of the fourth target reference current and the first heating current component, and the superposition result of the fourth target reference current and the second heating current component.

[0117] As an optional embodiment, a correspondence between the output torque and the d-axis and q-axis composite reference currents can be established in advance (e.g., by looking up a table or real-time calculation). After determining the target output torque, the d-axis composite reference current matching the target output torque can be determined based on this correspondence. Combined reference current with q-axis Here, the d-axis composite reference current and the q-axis composite reference current refer to the total d-axis current and total q-axis current of the two windings required to meet the target output torque. As an optional embodiment, the total current requirement can be evenly distributed across the two windings, i.e. As the third target reference current, As the fourth target reference current, it serves as the d-axis base current and q-axis base current for the two sets of windings, respectively.

[0118] In motion heating mode, to achieve simultaneous driving and heating, a heating current component needs to be superimposed on the aforementioned base current. Considering that the q-axis heating current components of the two windings are equal in magnitude and opposite in direction, ensuring that their additional torques cancel each other out, thus guaranteeing the total output torque by the base current, two different superposition methods are required for the q-axis currents of the two windings for distribution. Simultaneously, considering the long-term reliability and thermal balance of the system, two interchangeable distribution methods are provided, allowing the two windings to alternately bear positive and negative current biases during operation. This prevents a single winding from overheating due to prolonged exposure to large current biases, thus improving the system's lifespan and stability.

[0119] Based on the above considerations, a heating current component with the opposite direction is introduced into the q-axis control to achieve heating without affecting the total output torque. Specifically, a second candidate set is pre-constructed, which includes two superimposed results: one is the fourth target reference current and the first heating current component. The superposition result, i.e. Another component is the fourth target reference current combined with the second heating current component. The superposition result, i.e. These two superposition results correspond to two possible values ​​of the q-axis reference current for the two sets of windings, respectively.

[0120] When controlling the motor to heat the battery in motion heating mode, for the d-axis, the d-axis reference current of the first set of windings is used. d-axis reference current of the second set of windings All are set as the third target reference current, i.e. It is understandable that the d-axis current primarily affects the motor's magnetic field. Applying the same d-axis reference current to both windings will not generate additional torque disturbances and is beneficial for maintaining the symmetry of the magnetic field. For the q-axis, the superposition result is selected from the second candidate set for allocation: the q-axis reference current controlling the first winding is... The corresponding control of the q-axis reference current of the second set of windings is as follows: Alternatively, control the q-axis reference current of the first winding to be... The corresponding control of the q-axis reference current of the second set of windings is as follows: .

[0121] In one exemplary embodiment, controlling the q-axis reference current of the first set of windings to be a superposition result of one of the second candidate sets, and controlling the q-axis reference current of the second set of windings to be another superposition result of the second candidate set, includes:

[0122] In each odd-numbered sub-control cycle of the control cycle when the motor is in motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component is constant, and the amplitude of the second heating current component is constant.

[0123] In each even-numbered sub-control cycle of the control cycle when the motor is in motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of the second candidate set, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component changes continuously with time, and the amplitude of the second heating current component changes continuously with time.

[0124] Each control cycle is divided into multiple consecutive sub-control cycles, with the duration of odd-numbered sub-control cycles being longer than that of even-numbered sub-control cycles.

[0125] In this embodiment, when the motor is in a heating state, the motor's operating state can change periodically. This embodiment divides the control cycle T into multiple consecutive sub-control cycles. The number of sub-control cycles can be set according to actual engineering needs, and this embodiment does not impose a specific limitation. Since the control cycle is divided into multiple consecutive sub-control cycles, there are odd-numbered and even-numbered sub-control cycles. For example, assume the control cycle is divided into a first sub-control cycle, a second sub-control cycle, a third sub-control cycle, and a fourth sub-control cycle, where the first and third sub-control cycles are odd-numbered, and the second and fourth sub-control cycles are even-numbered. In this embodiment, the duration of the odd-numbered sub-control cycles is greater than the duration of the even-numbered sub-control cycles.

[0126] During the odd-numbered control cycle, the first heating current component Second heating current component The amplitude remains constant. The q-axis reference current of the first winding is... The q-axis reference current of the second winding is Alternatively, the allocation can be swapped, and the q-axis reference current of the first winding is... The q-axis reference current of the second winding is Furthermore, this characteristic remains constant throughout the entire odd-numbered sub-control cycle. This operating mode corresponds to the steady-state heating phase of the dynamic heating state, and its main task is to continuously output stable heating power. Because the amplitude of the heating current component is constant, the additional heat loss generated by the winding is also relatively stable, which is beneficial for achieving continuous and controllable heating of the battery. At the same time, the duration of the odd-numbered sub-control cycle is set to be relatively long so that steady-state heating occupies the main part of a control cycle, thereby ensuring overall heating efficiency.

[0127] During even-numbered sub-control cycles, the amplitudes of the first and second heating current components change continuously with time. Specifically, during even-numbered sub-control cycles, the amplitude of the heating current component changes from... Gradually decrease to Or the amplitude of the heating current component is determined by Gradually increase to Correspondingly, the q-axis reference current of the first winding and the second winding also transition smoothly, completing the interchange between the two distribution methods. This smooth transition avoids torque fluctuations and voltage surges caused by sudden current changes. Through the alternating coordination of the above-mentioned odd and even control cycles, within a complete control cycle T, the first and second windings alternately carry larger forward currents and smaller reverse currents, thereby making the contribution of the two windings to the total output torque more balanced, and the average heat generation of the two windings is also basically the same, achieving dynamic balance of thermal stress, which is beneficial to improving the reliability and lifespan of the motor during long-term operation.

[0128] As an optional implementation, the control period T can be divided into four sub-control periods. (Refer to...) Figure 6 and Figure 7 As shown:

[0129] exist During this period, the q-axis reference current of the first set of windings was The q-axis reference current of the second winding is ;

[0130] exist period, The amplitude changes linearly with respect to time, by Linear change is ;

[0131] exist During this period, the q-axis reference current of the first set of windings was The q-axis reference current of the second winding is ;

[0132] exist period, The amplitude changes linearly with respect to time, by Linear change is .

[0133] In one exemplary embodiment, the battery heating method further includes:

[0134] Determine the maximum allowable current for a single winding of the motor;

[0135] The first heating current component and the second heating current component are determined based on the maximum allowable current, the d-axis composite reference current, and the q-axis composite reference current.

[0136] In this embodiment, the heating current component can be calculated according to a preset formula. By introducing the maximum allowable current of a single winding As a constraint, when the superimposed heating current component is applied, it will not exceed the current carrying capacity limit of the winding, thereby avoiding safety problems such as winding overheating, insulation damage, or motor demagnetization caused by overcurrent.

[0137] As an optional embodiment, regardless of the heating state, the battery operating temperature needs to be measured once after each control cycle T. When the battery operating temperature rises to the third temperature threshold (the third temperature threshold is greater than the second temperature threshold), the motor heating state is terminated.

[0138] Please refer to Figure 8 , Figure 8 A flowchart illustrating the steps of a battery heating method for electric vehicles provided in this embodiment includes:

[0139] When the vehicle is stationary, determine whether the vehicle has sent a heating request; if not, end the process.

[0140] If so, confirm that the motor has entered a static heating state;

[0141] During the control period T , , as well as Each given current is assigned to a corresponding current, and it is determined whether the battery's operating temperature is greater than the second temperature threshold M. If not, the step of determining that the motor has entered a static heating state is initiated.

[0142] If so, confirm that the motor has entered the motion heating state;

[0143] During the control period T , , as well as Each given current is allocated accordingly, and it is determined whether the battery's operating temperature meets the standard (i.e., is greater than the third temperature threshold). If not, the step of determining that the motor has entered the motion heating state is initiated.

[0144] If the criteria are met, the process ends.

[0145] In summary, the solution proposed in this application achieves heating by increasing the output current of the motor without outputting torque in the static state through current distribution of the two sets of windings. In the dynamic state, the target current is redistributed to achieve heating by increasing the output current of the motor while outputting the target torque. Furthermore, this embodiment can heat the battery pack in both the static and dynamic states of the motor without the need for additional hardware, implementing the battery pack heating function from a software perspective, thus reducing costs.

[0146] This application provides a battery heating device, including:

[0147] The first determining module is used to determine the target heating state of the motor when the battery needs to be heated; the motor includes two sets of windings.

[0148] The first control module is used to increase the current of the two sets of windings if the target heating state is a static heating state, so that the combined torque generated by the motor in the two sets of windings is zero, while using the heat loss generated by the increased current to heat the battery.

[0149] Based on the above embodiments:

[0150] In an exemplary embodiment, increasing the current in the two sets of windings includes:

[0151] Determine the maximum allowable current for a single winding of the motor;

[0152] The current amplitude of the two windings is increased based on the maximum allowable current.

[0153] In one exemplary embodiment, increasing the magnitude of the current in both windings based on the maximum permissible current includes:

[0154] The d-axis reference current and q-axis reference current of the two windings are determined based on the maximum allowable current in order to increase the current amplitude of the two windings.

[0155] The amplitude and direction of the d-axis reference current of the two windings are the same, and the amplitude of the q-axis reference current of the two windings are the same but the directions are opposite.

[0156] In one exemplary embodiment, the two sets of windings include a first set of windings and a second set of windings;

[0157] The d-axis reference current and q-axis reference current of the two windings are determined based on the maximum allowable current, including:

[0158] The first target reference current and the second target reference current are determined based on the maximum allowable current. The first target reference current and the second target reference current have the same amplitude but opposite directions.

[0159] In each odd-numbered sub-control cycle of each control cycle when the motor is in a static heating state, the d-axis reference current and q-axis reference current of the first set of windings are both the first target reference current or both the second target reference current. The amplitude and phase of the d-axis reference current of the second set of windings are the same as those of the d-axis reference current of the first set of windings. The amplitude of the q-axis reference current of the second set of windings is the same as that of the d-axis reference current of the second set of windings, but the phases are opposite.

[0160] In the even-numbered sub-control cycles of each control cycle, the d-axis reference current and q-axis reference current of the second set of windings are both the first target reference current or both the second target reference current. The amplitude and direction of the d-axis reference current of the first set of windings and the d-axis reference current of the second set of windings are the same. The amplitude of the q-axis reference current of the first set of windings is the same as that of the d-axis reference current of the first set of windings, but the phases are opposite.

[0161] Each control cycle is divided into multiple consecutive sub-control cycles. In each control cycle, the d-axis reference current of the first set of windings switches direction at least once.

[0162] In one exemplary embodiment, the two sets of windings include a first set of windings and a second set of windings;

[0163] The battery heating device also includes:

[0164] The second control module is used to, if the target heating state is a motion heating state, add one heating current component from the first candidate set to the current allocated to the first set of windings based on the target output torque, and add another heating current component from the first candidate set to the current allocated to the second set of windings based on the target output torque, so that the motor can heat the battery by utilizing the heat loss generated by the superimposed heating current component while outputting the target output torque.

[0165] The two thermocurrent components in the first candidate set are the first thermocurrent component and the second thermocurrent component, which are opposite in direction.

[0166] In one exemplary embodiment, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, including:

[0167] Determine the d-axis composite reference current and the q-axis composite reference current based on the target output torque;

[0168] The third target reference current is determined based on the d-axis synthesized reference current, and the fourth target reference current is determined based on the q-axis synthesized reference current.

[0169] The d-axis reference current of both sets of windings is controlled to be the third target reference current;

[0170] The q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set;

[0171] Among them, the two superposition results in the second candidate set are: the superposition result of the fourth target reference current and the first heating current component, and the superposition result of the fourth target reference current and the second heating current component.

[0172] In one exemplary embodiment, controlling the q-axis reference current of the first set of windings to be a superposition result of one of the second candidate sets, and controlling the q-axis reference current of the second set of windings to be another superposition result of the second candidate set, includes:

[0173] In each odd-numbered sub-control cycle of the control cycle when the motor is in motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component is constant, and the amplitude of the second heating current component is constant.

[0174] In each even-numbered sub-control cycle of the control cycle when the motor is in motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of the second candidate set, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component changes continuously with time, and the amplitude of the second heating current component changes continuously with time.

[0175] Each control cycle is divided into multiple consecutive sub-control cycles, with the duration of odd-numbered sub-control cycles being longer than that of even-numbered sub-control cycles.

[0176] In one exemplary embodiment, the battery heating device further includes:

[0177] The second determining module is used to determine the maximum allowable current of a single winding of the motor;

[0178] The third determining module is used to determine the first heating current component and the second heating current component based on the maximum allowable current, the d-axis composite reference current, and the q-axis composite reference current.

[0179] This application also provides an electronic device, including:

[0180] Memory, used to store computer programs;

[0181] A processor for executing a computer program to implement the steps of the battery heating method as described in any of the embodiments above.

[0182] The electronic device also includes:

[0183] An input interface, connected to the processor, is used to acquire externally imported computer programs, parameters, and commands, and saves them to memory under the processor's control. This input interface can be connected to an input device to receive parameters or commands manually entered by the user. This input device can be a touch layer covering the display screen, or buttons, a trackball, or a touchpad located on the terminal casing.

[0184] The display unit, connected to the processor, is used to display the data sent by the processor. This display unit can be an LCD screen or an e-ink screen, etc.

[0185] The network port, connected to the processor, is used for communication with various external terminal devices. The communication technology used for this connection can be wired or wireless, such as Mobile High Definition Link (MHL), Universal Serial Bus (USB), High Definition Multimedia Interface (HDMI), Wireless Fidelity (WiFi), Bluetooth, Bluetooth Low Energy, or IEEE 802.11s-based communication technologies.

[0186] Of course, electronic devices may also include components such as power supplies.

[0187] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the battery heating method as described in any of the embodiments above.

[0188] The aforementioned computer-readable storage media may include, but are not limited to, USB flash drives, read-only memory (ROM), random access memory (RAM), portable hard drives, magnetic disks, or optical disks, and other media capable of storing computer programs.

[0189] It should also be noted that, in this specification, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0190] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery heating method, characterized in that, include: When the battery needs to be heated, the target heating state of the motor is determined; the motor includes two sets of windings. If the target heating state is a static heating state, the current of the two sets of windings is increased so that the combined torque generated by the motor from the two sets of windings is zero, while the heat loss generated by the increased current is used to heat the battery.

2. The battery heating method according to claim 1, characterized in that, Increasing the current in both sets of windings includes: Determine the maximum allowable current for a single winding of the motor; The amplitude of the current in the two sets of windings is increased based on the maximum allowable current.

3. The battery heating method according to claim 2, characterized in that, Increasing the current amplitude of the two sets of windings based on the maximum permissible current includes: The d-axis reference current and q-axis reference current of the two sets of windings are determined based on the maximum allowable current, so as to increase the current amplitude of the two sets of windings. The amplitude and direction of the d-axis reference current of the two sets of windings are the same, and the amplitude of the q-axis reference current of the two sets of windings is the same but the direction is opposite.

4. The battery heating method according to claim 3, characterized in that, The two sets of windings include a first set of windings and a second set of windings; Determining the d-axis reference current and q-axis reference current of the two sets of windings based on the maximum allowable current includes: A first target reference current and a second target reference current are determined based on the maximum allowable current, wherein the first target reference current and the second target reference current have the same amplitude but opposite directions; In each odd-numbered sub-control cycle of the control cycle when the motor is in the static heating state, the d-axis reference current and q-axis reference current of the first set of windings are controlled to be either the first target reference current or both the second target reference current; the amplitude and phase of the d-axis reference current of the second set of windings are controlled to be the same as those of the d-axis reference current of the first set of windings; and the amplitude of the q-axis reference current of the second set of windings is controlled to be the same as that of the d-axis reference current of the second set of windings, but the phases are opposite. In each even-numbered sub-control cycle of the control cycle, the d-axis reference current and q-axis reference current of the second set of windings are controlled to be either the first target reference current or both the second target reference current. The amplitude and direction of the d-axis reference current of the first set of windings and the d-axis reference current of the second set of windings are the same. The amplitude of the q-axis reference current of the first set of windings is the same as that of the d-axis reference current of the first set of windings, but the phases are opposite. Each control cycle is divided into multiple consecutive sub-control cycles, and in each control cycle, the d-axis reference current of the first set of windings switches direction at least once.

5. The battery heating method according to any one of claims 1-4, characterized in that, The two sets of windings include a first set of windings and a second set of windings; The battery heating method further includes: If the target heating state is a motion heating state, a heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque, and another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, so that the motor heats the battery by utilizing the heat loss generated by the superimposed heating current component while outputting the target output torque. The two heating current components in the first candidate set are: the first heating current component and the second heating current component, which are opposite in direction.

6. The battery heating method according to claim 5, characterized in that, A heating current component from the first candidate set is superimposed on the current allocated to the first set of windings based on the target output torque; another heating current component from the first candidate set is superimposed on the current allocated to the second set of windings based on the target output torque, including: Determine the d-axis composite reference current and the q-axis composite reference current based on the target output torque; A third target reference current is determined based on the d-axis synthesized reference current, and a fourth target reference current is determined based on the q-axis synthesized reference current. The d-axis reference current of both sets of windings is controlled to be the third target reference current; The q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; Among them, the two superposition results in the second candidate set are: the superposition result of the fourth target reference current and the first heating current component, and the superposition result of the fourth target reference current and the second heating current component.

7. The battery heating method according to claim 6, characterized in that, Controlling the q-axis reference current of the first set of windings to be a superposition result of one of the second candidate sets, and controlling the q-axis reference current of the second set of windings to be another superposition result of the second candidate set, includes: In each odd-numbered sub-control cycle of the control cycle in which the motor is in the motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component is constant, and the amplitude of the second heating current component is constant. During the even-numbered sub-control cycles of each control cycle in which the motor is in the motion heating state, the q-axis reference current of the first set of windings is controlled to be a superposition result of one of the second candidate sets, and the q-axis reference current of the second set of windings is controlled to be another superposition result of the second candidate set; the amplitude of the first heating current component changes continuously with time, and the amplitude of the second heating current component changes continuously with time. Each control cycle is divided into multiple consecutive sub-control cycles, and the duration of the odd-numbered sub-control cycles is longer than the duration of the even-numbered sub-control cycles.

8. The battery heating method according to claim 6, characterized in that, The battery heating method further includes: Determine the maximum allowable current for a single winding of the motor; The first heating current component and the second heating current component are determined based on the maximum allowable current, the d-axis composite reference current, and the q-axis composite reference current.

9. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor, configured to implement the steps of the battery heating method as described in any one of claims 1-8 when executing the computer program.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the battery heating method as described in any one of claims 1-8.

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