Power battery heating method, controller, power system, automobile and program product

Abstract

The invention provides a power battery heating method, a motor controller, a power system, an electric vehicle and a computer program product, and the method comprises the steps: detecting the position of a motor rotor of a driving motor in response to the condition of meeting the heating of a power battery; determining a target winding from the three-phase windings according to the relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the driving motor; and controlling the three-phase full-bridge inverter circuit to alternately work according to three periods so as to generate a heating current on a bus of the power battery, and enabling the phase current of the other two-phase windings except the target winding in the three-phase windings to flow in and the phase current of the target winding to flow out in each period. Thus, the target winding is determined according to the position of the rotor, and then a small current component is generated on the q axis of the motor, so that no high-frequency alternating electromagnetic torque is generated in the heating process, and NVH in the heating process can be reduced.

Description

Technical Field

[0001] The present disclosure relates to the technical field of motor control, and in particular to a power battery heating method, a power system, a vehicle, and a motor control method. Background Art

[0002] The discharge performance of the power battery of an electric vehicle is poor at low temperatures, so the power battery needs to have efficient low-temperature heating measures to ensure that the power battery pack can operate within a safe temperature range to meet the charging and discharging requirements of the entire vehicle.

[0003] At present, in order to reduce costs, pulse heating is usually used to directly heat the power battery. This method generates alternating current on the DC bus of the power battery by inputting voltage or current to the direct shaft of the motor, and uses the internal resistance of the power battery to generate ohmic heat to heat the battery. However, the current heating method will generate concentrated radial electromagnetic force, which will produce characteristic frequency resonance and then cause noise problems, resulting in obvious NVH (Noise, Vibration, Harshness). Summary of the invention

[0004] The embodiments of the present disclosure at least provide a power battery heating method, a power system, a vehicle and a motor control method, which can reduce the NVH generated by pulse heating of the power battery.

[0005] The embodiment of the present disclosure provides a power battery heating method, which is applied to a power system, wherein the power system includes a power battery, a drive motor, and an inverter connected between the power battery and the drive motor; the inverter includes a three-phase full-bridge inverter circuit; the method includes:

[0006] In response to satisfying a heating condition for the power battery, detecting a position of a motor rotor of the drive motor;

[0007] Determining a target winding from the three-phase windings according to a relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor;

[0008] The three-phase full-bridge inverter circuit is controlled to work alternately in three cycles to generate a heating current on the busbar of the power battery. In each cycle, the phase currents of the other two phase windings of the three-phase winding except the target winding flow in, and the phase current of the target winding flows out.

[0009] In a possible implementation manner, two ends of the power battery are connected to bus capacitors; the three cycles include a first cycle, a second cycle, and a third cycle; and controlling the three-phase full-bridge inverter circuit to work alternately according to the three cycles includes:

[0010] In the first cycle, the three-phase full-bridge inverter circuit is controlled to operate in a first operating mode, so as to control the power battery to charge the bus capacitor and the three-phase winding;

[0011] In the second period, the three-phase full-bridge inverter circuit is controlled to operate in the second operating mode, so that the bus capacitor releases energy to charge the power battery, and the current of the three-phase winding forms an internal circulation; the internal circulation refers to the phase current flowing out of the target winding, then flowing into the other two-phase windings and continuing to flow out of the target winding;

[0012] In the third period, the three-phase full-bridge inverter circuit is controlled to operate in a third operating mode so that the three-phase winding charges the power battery and the bus capacitor.

[0013] In a possible implementation manner, the amplitude direction of the phase current corresponding to the target winding is opposite to the amplitude direction of the phase current corresponding to the other two-phase windings; the three cycles include a first cycle, a second cycle and a third cycle;

[0014] In the first cycle, the amplitude of the phase current of each phase winding increases gradually according to the first slope to the corresponding first preset current in the first cycle;

[0015] In the second period, the amplitude of the phase current of each phase winding decreases from the first preset current to the corresponding second preset current according to a second slope, and the second slope is smaller than the first slope;

[0016] In the third period, the amplitude of the phase current of each phase winding decreases from the second preset current to a corresponding third preset current according to a third slope in the third period, and the third slope is greater than the second slope.

[0017] In a possible implementation manner, the three cycles form a heating period cycle, and the three heating period cycles constitute a heating cycle, and the method further includes:

[0018] The power battery is pulse heated according to the heating cycle; in each heating cycle, the target windings corresponding to the three heating time periods are different.

[0019] In a possible implementation manner, the midpoint of each bridge arm in the three-phase full-bridge inverter circuit is respectively connected to a phase winding; and in the second period, controlling the three-phase full-bridge inverter circuit to operate in the second operating mode includes:

[0020] In the second period, the upper bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned off.

[0021] In a possible implementation manner, in the first period, controlling the three-phase full-bridge inverter circuit to operate in the first operating mode includes:

[0022] In the first cycle, the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned on, and the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned off; and / or,

[0023] In the third period, controlling the three-phase full-bridge inverter circuit to operate in the third operating mode includes:

[0024] In the third cycle, the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned on, and the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned off.

[0025] In a possible implementation manner, determining a target winding from the three-phase windings according to a relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor includes:

[0026] Determine the angle between the motor rotor and each phase winding of the three-phase winding;

[0027] The winding whose angle with the motor rotor is within a preset angle range is determined as the target winding; the preset angle range includes a first preset angle range and a second preset angle range, the first preset angle range is -30° to 30 degrees, and the second preset angle range is -150° to 210°.

[0028] In a possible implementation, the method further includes:

[0029] If the angle between the motor rotor and the target winding is within the first preset angle range, controlling the drive motor to rotate so that the angle between the motor rotor and the target winding is 0°;

[0030] If the angle between the motor rotor and the target winding is within the second preset angle range, the drive motor is controlled to rotate so that the angle between the motor rotor and the target winding is 180°.

[0031] The present disclosure provides a motor controller, comprising:

[0032] a memory configured to store instructions; and

[0033] The processor is configured to call the instruction from the memory and implement the power battery heating method according to any possible implementation manner described above when executing the instruction.

[0034] An embodiment of the present disclosure provides a power system, including a power battery, an inverter, a drive motor and the motor controller described in the above embodiment, wherein the DC side of the inverter is connected to the power battery, the AC side of the inverter is connected to the drive motor, and the power battery, the inverter and the drive motor are all connected to the motor controller.

[0035] An embodiment of the present disclosure provides an electric vehicle, comprising a power system according to the above-mentioned embodiment.

[0036] An embodiment of the present disclosure provides a computer program product, including a computer program. When the computer program is executed by a computer device or a processor, the computer device or the processor executes the power battery heating method described in any possible implementation manner described above.

[0037] The power battery heating method, power system, electric vehicle and computer program product provided by the embodiment of the present disclosure first detect the position of the motor rotor of the drive motor under the heating conditions of the power battery, and determine the target winding from the three-phase winding according to the relative position relationship between the position of the motor rotor and each winding in the three-phase winding of the drive motor; then control the three-phase full-bridge inverter circuit to work alternately according to three cycles, and for each cycle, the phase currents of the other two phase windings in the three-phase winding except the target winding flow in, and the phase current of the target winding flows out. In this way, the target winding is determined according to the rotor position for optimal control, and then a smaller current component is generated in the q-axis of the motor, so that no high-frequency alternating electromagnetic torque is generated during the heating process, thereby reducing NVH during the heating process.

[0038] In order to make the above-mentioned objectives, features and advantages of the present disclosure more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following is a brief introduction to the drawings required for use in the embodiments. The drawings herein are incorporated into the specification and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and are used together with the specification to illustrate the technical solutions of the present disclosure. It should be understood that the following drawings only illustrate certain embodiments of the present disclosure and should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings without creative work.

[0040] Figure 1 A principle block diagram of an electric vehicle provided by an embodiment of the present disclosure is shown;

[0041] Figure 2 A schematic structural diagram of a power battery provided by an embodiment of the present disclosure is shown;

[0042] Figure 3 A circuit schematic diagram of a power system provided by an embodiment of the present disclosure is shown;

[0043] Figure 4 A flow chart of a power battery heating method provided by an embodiment of the present disclosure is shown;

[0044] Figure 5 A schematic diagram showing a position relationship between a rotor and a stator provided in an embodiment of the present disclosure is shown;

[0045] Figure 6 Shows Figure 3 Schematic diagram of current flow in the second cycle when the power system in FIG. takes the A-phase winding as the target winding;

[0046] Figure 7 Shows Figure 3 Schematic diagram of current flow in the third cycle when the power system in FIG. takes the A-phase winding as the target winding;

[0047] Figure 8 Shows Figure 3 Schematic diagram of current flow in the first cycle when the power system in FIG. 1 takes the B-phase winding as the target winding;

[0048] Fig. 9 Shows Figure 3 Schematic diagram of current flow in the second cycle when the power system in FIG. takes the B-phase winding as the target winding;

[0049] Fig.10 Shows Figure 3 Schematic diagram of current flow in the third cycle when the power system in FIG. 1 takes the B-phase winding as the target winding;

[0050] Fig.11 Shows Figure 3 Schematic diagram of current flow in the first cycle when the power system in FIG. 1 takes the C-phase winding as the target winding;

[0051] Fig.12 Shows Figure 3 Schematic diagram of current flow in the second cycle when the power system in FIG. takes the C-phase winding as the target winding;

[0052] Fig.13 Shows Figure 3 Schematic diagram of current flow in the third cycle when the power system in FIG. 1 takes the C-phase winding as the target winding;

[0053] Fig.14 Shows Figure 3 A phase current waveform diagram when the power system in the figure takes the A phase winding as the target winding;

[0054] Fig.15 Shows Figure 3 The B-phase current waveform diagram when the power system in the figure takes the A-phase winding as the target winding;

[0055] Fig.16 Shows Figure 3 The C-phase current waveform diagram when the power system in the figure takes the A-phase winding as the target winding;

[0056] Fig.17 A functional module diagram of a motor controller provided by an embodiment of the present disclosure is shown;

[0057] Fig.18 A schematic structural diagram of a motor controller provided by an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical scheme and advantages of the embodiments of the present disclosure clearer, the technical scheme in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The components of the embodiments of the present disclosure generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present disclosure provided in the drawings is not intended to limit the scope of the present disclosure for protection, but merely represents the selected embodiments of the present disclosure. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present disclosure.

[0059] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0060] The term "and / or" herein only describes an association relationship, indicating that three relationships may exist. For example, A and / or B may represent the following three situations: A exists alone, A and B exist at the same time, and B exists alone. In addition, the term "at least one" herein represents any combination of at least two of any one or more of a plurality of. For example, including at least one of A, B, and C may represent including any one or more elements selected from the set consisting of A, B, and C.

[0061] In the following description of this application, unless otherwise clearly specified and limited, the term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integrated connection; it can be a direct connection or an indirect connection through an intermediate medium.

[0062] Research has found that the current pulse heating method of power batteries will generate concentrated radial electromagnetic force, which will produce characteristic frequency resonance and then cause noise problems, resulting in obvious NVH (Noise, Vibration, Harshness).

[0063] Based on the above research, the embodiment of the present disclosure provides a power battery heating method, a power system, an electric vehicle and a computer program product. When the heating conditions for the power battery are met, the position of the motor rotor of the drive motor is first detected, and the target winding is determined from the three-phase winding according to the relative position relationship between the position of the motor rotor and each winding in the three-phase winding of the drive motor; then the three-phase full-bridge inverter circuit is controlled to work alternately according to three cycles, and for each cycle, the phase currents of the other two phase windings in the three-phase winding except the target winding flow in, and the phase current of the target winding flows out. In this way, the target winding is determined according to the rotor position for optimal control, and then a smaller current component is generated in the q-axis of the motor, so that no high-frequency alternating electromagnetic torque is generated during the heating process, thereby reducing NVH during the heating process.

[0064] See also Figure 1 , Figure 1 The following is a block diagram of an electric vehicle provided by an embodiment of the present disclosure. Figure 1 As shown, the electric vehicle 1000 includes a power system 100 and a wheel 200. The power system 100 is connected to the wheel 200 to provide power to the wheel 200 to drive the wheel 200 to rotate, thereby providing power for the electric vehicle 1000 to travel.

[0065] In the disclosed embodiment, the electric vehicle 1000 may be a vehicle powered by a power battery 200. Specifically, the electric vehicle 1000 may include a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), etc., without specific limitation.

[0066] Specifically, the power system 100 includes a power battery 10, an inverter 20, a drive motor 30 and a motor controller 50. The DC side of the inverter 20 is connected to the power battery 10, and the AC side of the inverter 20 is connected to the drive motor 30. The power battery 10, the inverter 20 and the drive motor 30 are all connected to the motor controller.

[0067] Of course, the power system 100 may also include other components, which are not specifically limited here.

[0068] The power battery 10 is used to store and provide electrical energy. The power battery 10 includes but is not limited to a lead-acid battery, a lithium iron phosphate battery, a nickel-hydrogen battery, a nickel-cadmium battery, etc. In some embodiments, the power battery 10 may also include a supercapacitor.

[0069] The drive motor 30 (commonly known as "motor") refers to an electromagnetic device that realizes electric energy conversion or transmission according to the law of electromagnetic induction, which is electrically connected to the motor controller 50 and connected to the wheel 200. Its main function is to generate driving torque as a power source for the wheel 200. In some embodiments, the drive motor 30 can also convert mechanical energy into electrical energy, that is, it can be used as a generator.

[0070] The motor controller 50 is an integrated circuit that actively controls the drive motor 30 to operate in a set direction, speed, angle, and response time. In the electric vehicle 1000, the function of the motor controller 50 is to convert the electric energy stored in the power battery 10 into the electric energy required by the drive motor 30 according to the gear position, accelerator, brake and other instructions, to control the start-up operation, forward and backward speed, climbing strength and other driving states of the electric vehicle 1000, or to help the electric vehicle 1000 brake and store part of the braking energy in the power battery 10.

[0071] See also Figure 2As shown, the power battery 10 may include a battery module 11 and a battery management system (BMS) 12. The battery module 11 is composed of a plurality of single cells (also called battery cells) connected in series and in parallel. The single cell is the core component of the power battery 10 and is the source of power provided by the power battery 10. The single cell includes but is not limited to lead-acid batteries, lithium iron phosphate batteries, nickel-hydrogen batteries, nickel-cadmium batteries, etc.

[0072] In practical applications, the number of the plurality of single cells included in the battery module 11 can be determined according to actual needs. For example, if a higher voltage (such as 800V) is to be output, a larger number of single cells is required.

[0073] The main functions of the battery management system 12 are to manage charge and discharge, high voltage control, evaluate battery status, collect battery data, protect batteries, and manage battery thermally. Among them, the thermal management function in the battery management system 12 is used to ensure that the battery module 11 operates within an appropriate temperature range. The thermal management function is mainly to achieve accurate measurement and monitoring of battery temperature, effective heat dissipation when the temperature of the battery module 11 is too high, rapid heating under low temperature conditions, and ensure uniform distribution of the temperature field of the battery module 11.

[0074] Exemplarily, the battery management system 12 is connected to the motor controller 50, and can monitor the temperature of the battery module 11 and send the detected temperature to the motor controller 50. It can be understood that in other embodiments, the battery management system 12 can also be provided independently of the battery module 11, that is, in some embodiments, the power battery 10 can include only the battery module 11, but not the battery management system 12.

[0075] See also Figure 3 As shown, the inverter 20 includes power switch devices S1-S6, which constitute the three-phase bridge arm of the inverter 20. Exemplarily, the power switch devices S1-S6 can be insulated gate bipolar transistors (IGBT), metal oxide semiconductor field effect transistors (MOSFET) or silicon carbide metal oxide semiconductor (SiC MOSFET), etc., and the embodiment of the present application does not specifically limit this.

[0076] Specifically, the motor controller 50 can obtain the temperature of the power battery 10 through the battery management system 12, and when the temperature of the power battery 10 meets the heating conditions, send a control signal to the inverter 20, such as a pulse width modulation (PWM) signal, to control the working state of the power switching devices S1~S6, for example, by changing the duty cycle of the control signal to change the conduction time of the power switching device, so that a high-frequency current will be generated on the DC bus of the power battery 10 and flow through the power battery 10, and then the ohmic heat generated by the internal resistance of the power battery 10 can be used to heat the power battery 10.

[0077] The power battery heating method provided by the embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0078] See also Figure 4 , which is a flow chart of a power battery heating method provided by an embodiment of the present disclosure, the method is applied to the aforementioned power system 100, and the method includes the following S101 to S103:

[0079] S101 , in response to satisfying a heating condition for the power battery, detecting a position of a motor rotor of the drive motor.

[0080] For example, please refer again to Figure 1-2 , the temperature of the power battery 10 can be detected by the battery management system 12, and then the detected temperature is sent to the motor controller 50. When the temperature of the power battery 10 is lower than a preset threshold, it is determined that the power battery 10 meets the heating condition.

[0081] If it is determined that the power battery 10 meets the heating condition, the position of the motor rotor of the drive motor 30 can be detected. Exemplarily, the position of the motor rotor can be detected by a Hall sensor, an encoder, or the like.

[0082] S102, determining a target winding from the three-phase windings according to a relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor.

[0083] For example, see Figure 5 As shown, after the rotor position of the motor rotor is detected, the target winding can be determined from the three-phase winding according to the relative position relationship between the position of the motor rotor and each winding in the three-phase winding of the drive motor. The three-phase winding is also called the stator winding of the drive motor. In the disclosed embodiment, the three-phase winding is described by taking the A-phase winding, the B-phase winding and the C-phase winding as examples.

[0084] Specifically, the target winding may be determined according to the angle between the motor rotor and each phase winding in the three-phase winding. Therefore, in some embodiments, determining the target winding from the three-phase winding according to the relative position relationship between the position of the motor rotor and each winding in the three-phase winding of the drive motor may include the following:

[0085] Determine the angle between the motor rotor and each phase winding in the three-phase winding, and determine the winding whose angle with the motor rotor is within a preset angle range as the target winding; the preset angle range includes a first preset angle range and a second preset angle range, the first preset angle range is -30° to 30°, and the second preset angle range is -150° to 210°. Figure 5 As shown, since the angle between the A-phase winding and the rotor position of the motor rotor is between -30° and 30°, the A-phase winding can be determined as the target winding. Of course, in other embodiments, the first preset angle range and the second preset angle range can also be larger or smaller ranges, which are not specifically limited here.

[0086] In this way, no matter where the motor rotor is currently located, the corresponding target winding can be determined, which is beneficial to improving the efficiency and accuracy of determining the target winding.

[0087] S103, controlling the three-phase full-bridge inverter circuit to work alternately in three cycles to generate a heating current on the busbar of the power battery, wherein in each cycle, phase currents of two phase windings other than the target winding among the three-phase windings flow in, and phase current of the target winding flows out.

[0088] Please refer again Figure 3 , bus capacitors 40 are connected to both ends of the power battery 10. The three cycles may include a first cycle T1, a second cycle T2 and a third cycle T3. After determining the target winding, the three-phase full-bridge inverter circuit can be controlled to work alternately according to three cycles T1, T2 and T3 to generate a pulse heating current on the bus of the power battery 10, thereby heating the power battery 10. For each cycle, the phase currents of the other two phase windings except the target winding in the three-phase winding flow in, and the phase current of the target winding flows out. Among them, the three-phase windings of the drive motor have a common node, and the phase current inflow refers to the flow from one end of each phase winding to the common node end, and the phase current outflow refers to the flow from the common node end to the other end. As Figure 3 As shown, the phase current of the B-phase winding and the phase current of the C-phase winding flow in, and the phase current of the A-phase winding (target winding) flows out.

[0089] Specifically, in the first cycle T1, the power battery charges the bus capacitor and the three-phase winding; in the second cycle T2, the bus capacitor releases energy to charge the power battery, and the phase currents of the three-phase winding form an internal loop; the internal loop refers to the phase current flowing out of the target winding, then flowing into the other two-phase windings and continuing to flow out of the target winding; in the third cycle T3, the three-phase winding charges the power battery and the bus capacitor.

[0090] Therefore, in some embodiments, the controlling the three-phase full-bridge inverter circuit to work alternately according to three cycles may include the following (1) to (3):

[0091] (1) In the first cycle, the three-phase full-bridge inverter circuit is controlled to operate in a first operating mode, so as to control the power battery to charge the bus capacitor and the three-phase winding;

[0092] (2) in the second period, controlling the three-phase full-bridge inverter circuit to operate in the second operating mode, so that the bus capacitor releases energy to charge the power battery, and the phase currents of the three-phase windings form an internal loop current;

[0093] (3) During the third period, the three-phase full-bridge inverter circuit is controlled to operate in a third operating mode so that the three-phase winding charges the power battery and the bus capacitor.

[0094] In the disclosed embodiment, since the three-phase current of the motor forms an internal circulation in the second period T2, the peak value of the three-phase current can be reduced to avoid phase current overcurrent, thereby increasing the bus current, which is beneficial to improving the battery heating rate.

[0095] Optionally, before controlling the three-phase full-bridge inverter circuit to work alternately in three cycles, if the angle between the motor rotor and the target winding is within the first preset angle range, the drive motor can be controlled to rotate so that the angle between the motor rotor and the target winding is 0°; if the angle between the motor rotor and the target winding is within the second preset angle range, the drive motor can be controlled to rotate so that the angle between the motor rotor and the target winding is 180°. In this way, the rotor position of the motor rotor can be overlapped with the adjacent phase, and no current component is generated on the motor q axis, which is conducive to further reducing NVH during the heating process.

[0096] In some embodiments, the three cycles form a heating period cycle, and the three heating period cycles constitute a heating cycle. The method also includes: pulse heating the power battery according to the heating cycle; in each of the heating cycles, the target windings corresponding to the three heating period cycles are different.

[0097] That is, the first cycle T1, the second cycle T2 and the third cycle T3 can form a heating period cycle t, and the three heating period cycles (t1, t2, t3) form a heating period K. For each heating period cycle in each heating period K, the corresponding target winding is different. For example, if the target winding corresponding to the first heating period cycle t1 is the A-phase winding, the target winding corresponding to the second heating period cycle t2 can be one of the B-phase winding and the C-phase winding, and the target winding corresponding to the third heating period cycle t3 can be the other of the B-phase winding and the C-phase winding.

[0098] The target winding corresponding to the first heating period cycle t1 can be determined according to the rotor position of the motor rotor, and the target windings corresponding to the second heating period cycle t2 and the third heating period cycle t3 can be determined according to preset rules.

[0099] In this embodiment, since the target windings corresponding to different heating period cycles are different, the A / B / C three-phase periodic current can be maximized, so that each phase winding is heated evenly and the stator temperature rises evenly, which can avoid the overheating of the motor caused by the maximum current and loss of one fixed phase winding, which is beneficial to extend the heating time and increase the maximum heating temperature of the power battery.

[0100] Specifically, the midpoint of each bridge arm in the three-phase full-bridge inverter circuit is respectively connected to a phase winding; in the first cycle, controlling the three-phase full-bridge inverter circuit to operate in the first operating mode may include: in the first cycle, controlling the upper bridge arms corresponding to the other two-phase windings and the lower bridge arm corresponding to the target winding to be turned on, and controlling the lower bridge arms corresponding to the other two-phase windings and the upper bridge arm corresponding to the target winding to be turned off;

[0101] Controlling the three-phase full-bridge inverter circuit to operate in the second operating mode during the second cycle may include: controlling the upper bridge arm of each bridge arm in the three-phase full-bridge inverter circuit to be turned on, and controlling the lower bridge arm of each bridge arm in the three-phase full-bridge inverter circuit to be turned off during the second cycle.

[0102] Controlling the three-phase full-bridge inverter circuit to operate in the third operating mode during the third cycle may include: controlling the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding to be turned on, and controlling the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding to be turned off during the third cycle.

[0103] The following describes the operation of the three-phase full-bridge inverter circuit in the aforementioned three cycles, taking the A-phase winding, the B-phase winding and the C-phase winding as target windings as examples.

[0104] For the case where the A-phase winding is the target winding, such as Figure 3 As shown, in the first cycle T1, the upper bridge arms (S3 and S5) corresponding to the B and C two-phase windings and the lower bridge arm (S2) corresponding to the A phase winding are controlled to be turned on, and the lower bridge arms (S4 and S6) corresponding to the B and C two-phase windings and the upper bridge arm (S1) corresponding to the A phase winding are controlled to be disconnected. At this time, the power battery 10 charges the bus capacitor 40 and the three-phase windings (A, B, C). In the second cycle T2, see Figure 6 As shown, the upper bridge arm of each bridge arm (S1, S3 and S5) in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm (S2, S4 and S6) of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be disconnected. At this time, the bus capacitor 40 releases energy to charge the power battery 10, and the phase currents of the three-phase windings (A, B, C) form an internal loop. In the third period T3, see Figure 7 As shown, the lower bridge arms (S4 and S6) corresponding to the B and C phase windings and the upper bridge arm (S1) corresponding to the A phase winding are controlled to be turned on, and the upper bridge arms (S3 and S5) corresponding to the B and C phase windings and the lower bridge arm (S2) corresponding to the A phase winding are controlled to be disconnected. At this time, the three-phase windings (A, B, C) charge the power battery 10 and the bus capacitor 40.

[0105] For the case where the B-phase winding is the target winding, see Figure 8 As shown, in the first cycle T1, the upper bridge arms (S1 and S5) corresponding to the A and C two-phase windings and the lower bridge arm (S4) corresponding to the B phase winding are controlled to be turned on, and the lower bridge arms (S2 and S6) corresponding to the A and C two-phase windings and the upper bridge arm (S3) corresponding to the B phase winding are controlled to be disconnected. At this time, the power battery 10 charges the bus capacitor 40 and the three-phase windings (A, B, C). In the second cycle T2, see Fig. 9 As shown, the upper bridge arm of each bridge arm (S1, S3 and S5) in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm (S2, S4 and S6) of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be disconnected. At this time, the bus capacitor 40 releases energy to charge the power battery 10, and the phase currents of the three-phase windings (A, B, C) form an internal loop. In the third period T3, see Fig.10As shown, the lower bridge arms (S2 and S6) corresponding to the A and C phase windings and the upper bridge arm (S3) corresponding to the B phase winding are controlled to be turned on, and the upper bridge arms (S1 and S5) corresponding to the A and C phase windings and the lower bridge arm (S4) corresponding to the B phase winding are controlled to be disconnected. At this time, the three-phase windings (A, B, C) charge the power battery 10 and the bus capacitor 40.

[0106] For the case where the C phase winding is the target winding, see Fig.11 As shown, in the first cycle T1, the upper bridge arms (S1 and S3) corresponding to the A and B two-phase windings and the lower bridge arm (S6) corresponding to the C phase winding are controlled to be turned on, and the lower bridge arms (S2 and S4) corresponding to the A and B two-phase windings and the upper bridge arm (S5) corresponding to the B phase winding are controlled to be disconnected. At this time, the power battery 10 charges the bus capacitor 40 and the three-phase windings (A, B, C). In the second cycle T2, see Fig.12 As shown, the upper bridge arm of each bridge arm (S1, S3 and S5) in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm (S2, S4 and S6) of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be disconnected. At this time, the bus capacitor 40 releases energy to charge the power battery 10, and the phase currents of the three-phase windings (A, B, C) form an internal loop. In the third period T3, see Fig.13 As shown, the lower bridge arms (S2 and S4) corresponding to the A and B phase windings and the upper bridge arm (S5) corresponding to the C phase winding are controlled to be turned on, and the upper bridge arms (S1 and S3) corresponding to the A and B phase windings and the lower bridge arm (S6) corresponding to the C phase winding are controlled to be disconnected. At this time, the three-phase windings (A, B, C) charge the power battery 10 and the bus capacitor 40.

[0107] in, Figure 3 , Figure 6-Figure 13 The direction of the arrows in the various circuit diagrams is used to indicate the direction of current flow.

[0108] The waveforms of the currents of each phase in the embodiment of the present disclosure are described below with reference to the accompanying drawings, taking the A-phase winding as the target winding as an example.

[0109] In some implementations, the amplitude direction of the phase current corresponding to the target winding (such as the A-phase winding) is opposite to the amplitude direction of the phase current corresponding to the other two-phase windings (B-phase winding and C-phase winding). Figure 14-16 As shown, the phase current of the A-phase winding is in the negative direction, the phase currents of the B and C windings are in the positive direction, and each phase current is a half-wave current, wherein the half-wave current refers to a current that includes only positive cycles or only negative cycles.

[0110] During the first period T1, the amplitude of the phase current of each phase winding increases according to the first slope to the corresponding first preset current; during the second period T2, the amplitude of the phase current of each phase winding decreases from the first preset current to the corresponding second preset current according to the second slope, and the second slope is smaller than the first slope; during the third period T3, the amplitude of the phase current of each phase winding decreases from the second preset current to the corresponding third preset current according to the third slope, and the third slope is larger than the second slope.

[0111] Among them, the preset currents corresponding to different phase windings can be the same or different. For example, when the A-phase winding is the target winding, the first preset currents corresponding to the B-phase winding and the C-phase winding can be the same, the second preset currents corresponding to the B-phase winding and the C-phase winding can be the same, the third preset currents corresponding to the B-phase winding and the C-phase winding can be the same, the first preset current corresponding to the A-phase winding can be twice the first preset current corresponding to the B-phase winding or the C-phase winding. Similarly, the second preset current corresponding to the A-phase winding is also twice the second preset current corresponding to the B-phase winding or the C-phase winding, and the third preset current corresponding to the A-phase winding is also twice the third preset current corresponding to the B-phase winding or the C-phase winding.

[0112] In the disclosed embodiment, since each phase current corresponding to the electronic three-phase winding is a half-wave current without positive and negative alternation, the eddy current loss of the rotor magnetic steel can be reduced, which is beneficial to reducing the temperature rise rate of the motor rotor and increasing the pulse heating time.

[0113] The power battery heating method provided by the embodiment of the present disclosure first detects the position of the motor rotor of the drive motor, and determines the target winding from the three-phase winding according to the relative position relationship between the position of the motor rotor and each winding in the three-phase winding of the drive motor; then controls the three-phase full-bridge inverter circuit to work alternately according to three cycles, and for each cycle, the phase currents of the other two phase windings in the three-phase winding except the target winding flow in, and the phase currents flow out from the target winding. In this way, the target winding is determined according to the rotor position for optimal control, and then a smaller current component is generated in the motor q-axis, so that no high-frequency alternating electromagnetic torque is generated during the heating process, thereby reducing NVH during the heating process.

[0114] Those skilled in the art will appreciate that, in the above method of specific implementation, the order in which the steps are written does not imply a strict execution order and does not constitute any limitation on the implementation process. The specific execution order of the steps should be determined by their functions and possible internal logic.

[0115] See also Fig.17 , which is a functional module diagram of a motor controller provided by an embodiment of the present disclosure. The motor controller 50 includes:

[0116] The rotor position detection module 51 is used to detect the position of the motor rotor of the drive motor in response to the heating condition for the power battery being met.

[0117] The target winding determination module 52 is used to determine the target winding from the three-phase windings according to the relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor.

[0118] The battery heating control module 53 is used to control the three-phase full-bridge inverter circuit to work alternately in three cycles to generate a heating current on the bus of the power battery, the phase currents of the other two phase windings of the three-phase winding except the target winding flow into the winding, and the phase current of the target winding flows out.

[0119] In a possible implementation manner, the two ends of the power battery are connected to bus capacitors; the three cycles include a first cycle, a second cycle, and a third cycle; the battery heating control module 53 is specifically used for:

[0120] In the first cycle, the three-phase full-bridge inverter circuit is controlled to operate in a first operating mode, so as to control the power battery to charge the bus capacitor and the three-phase winding;

[0121] In the second period, the three-phase full-bridge inverter circuit is controlled to operate in the second operating mode, so that the bus capacitor releases energy to charge the power battery, and the phase currents of the three-phase windings form an internal circulation current; the internal circulation current refers to the phase current flowing out of the target winding, then flowing into the other two-phase windings and continuing to flow out of the target winding;

[0122] In the third period, the three-phase full-bridge inverter circuit is controlled to operate in a third operating mode so that the three-phase winding charges the power battery and the bus capacitor.

[0123] In a possible implementation manner, the amplitude direction of the phase current corresponding to the target winding is opposite to the amplitude direction of the phase current corresponding to the other two-phase windings, and the phase current corresponding to each phase winding is a half-wave current; the three cycles include a first cycle, a second cycle and a third cycle;

[0124] In the first cycle, the amplitude of the phase current of each phase winding increases gradually according to the first slope to the corresponding first preset current in the first cycle;

[0125] In the second period, the amplitude of the phase current of each phase winding decreases from the first preset current to the corresponding second preset current according to a second slope, and the second slope is smaller than the first slope;

[0126] In the third period, the amplitude of the phase current of each phase winding decreases from the second preset current to a corresponding third preset current according to a third slope in the third period, and the third slope is greater than the second slope.

[0127] In a possible implementation manner, the three cycles form a heating period cycle, and the three heating period cycles constitute a heating cycle. The battery heating control module 53 is further used for:

[0128] The power battery is pulse heated according to the heating cycle; in each heating cycle, the target windings corresponding to the three heating time periods are different.

[0129] In a possible implementation manner, the midpoint of each bridge arm in the three-phase full-bridge inverter circuit is respectively connected to a phase winding; the battery heating control module 53 is specifically used for:

[0130] In the second period, the upper bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned off.

[0131] In a possible implementation manner, the battery heating control module 53 is specifically used to:

[0132] In the first cycle, the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned on, and the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned off; and / or,

[0133] In the third cycle, the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned on, and the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned off.

[0134] In a possible implementation manner, the target winding determination module 52 is specifically configured to:

[0135] Determine the angle between the motor rotor and each phase winding of the three-phase winding;

[0136] The winding whose angle with the motor rotor is within a preset angle range is determined as the target winding; the preset angle range includes a first preset angle range and a second preset angle range, the first preset angle range is -30° to 30°, and the second preset angle range is -150° to 210°.

[0137] In a possible implementation manner, the target winding determination module 52 is further configured to:

[0138] If the angle between the motor rotor and the target winding is within the first preset angle range, controlling the drive motor to rotate so that the angle between the motor rotor and the target winding is 0°;

[0139] If the angle between the motor rotor and the target winding is within the second preset angle range, the drive motor is controlled to rotate so that the angle between the motor rotor and the target winding is 180°.

[0140] For the description of the components involved in the processing of each module in the device, reference can be made to the relevant description in the above method embodiment, which will not be described in detail here.

[0141] Based on the same technical concept, see Fig.18 , which is a schematic diagram of the structure of a motor controller provided by an embodiment of the present disclosure, includes a processor 501, a memory 502, and a bus 503. The memory 502 is used to store execution instructions.

[0142] In the disclosed embodiment, the memory 502 is specifically used to store the application code for executing the solution of the present application, and the execution is controlled by the processor 501. That is, when the motor controller 50 is running, the processor 501 communicates with the memory 502 through the bus 503, so that the processor 501 executes the application code stored in the memory 502, and then executes the method described in any of the above embodiments.

[0143] Among them, the memory 502 can be, but is not limited to, random access memory (Random Access Memory, RAM), read only memory (Read Only Memory, ROM), programmable read-only memory (Programmable Read-Only Memory, PROM), erasable programmable read-only memory (Erasable Programmable Read-Only Memory, EPROM), electrically erasable read-only memory (Electric Erasable Programmable Read-Only Memory, EEPROM), etc.

[0144] Processor 501 may be an integrated circuit chip with signal processing capabilities. The above-mentioned processor may be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it may also be a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components. The disclosed methods, steps and logic block diagrams in the embodiments of the present invention may be implemented or executed. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0145] It is understood that the structure illustrated in the embodiment of the present application does not constitute a specific limitation on the motor controller 50. In other embodiments of the present application, the motor controller 50 may include more or fewer components than shown in the figure, or combine certain components, or split certain components, or arrange the components differently. The components shown in the figure may be implemented in hardware, software, or a combination of software and hardware.

[0146] The embodiment of the present disclosure further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the motor control method in the above method embodiment are executed.

[0147] The embodiments of the present disclosure also provide a computer program product, including a computer program / instruction. When the computer program / instruction processor is executed, the motor control method provided in the embodiments of the present disclosure is implemented. For details, please refer to the above method embodiments, which will not be repeated here.

[0148] The computer program product may be implemented in hardware, software or a combination thereof. In one optional embodiment, the computer program product is implemented as a computer storage medium. In another optional embodiment, the computer program product is implemented as a software product, such as a software development kit (SDK).

[0149] The method in the embodiments of the present disclosure may be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it may be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer programs or instructions. When the computer program or instruction is downloaded and executed on a computer, the process or function described in the present application is executed in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, a network device, a user device, a core network device, an OAM or other programmable device.

[0150] The computer program or instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium, for example, the computer program or instructions may be transmitted from one website, computer, server or data center to another website, computer, server or data center by wired or wireless means. The computer-readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium may be a magnetic medium, such as a floppy disk, a hard disk, or a magnetic tape; it may also be an optical medium, such as a digital video disk; it may also be a semiconductor medium, such as a solid-state drive. The computer-readable storage medium may be a volatile or non-volatile storage medium, or may include both volatile and non-volatile types of storage media.

[0151] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, the specific working process of the system and device described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here. In the several embodiments provided in the present disclosure, it should be understood that the disclosed system, device and method can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of the device or unit can be electrical, mechanical or other forms.

[0152] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0153] In addition, each functional unit in each embodiment of the present disclosure may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0154] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a non-volatile computer-readable storage medium that is executable by a processor. Based on this understanding, the technical solution of the present disclosure, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present disclosure. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a ROM, a RAM, a magnetic disk, or an optical disk.

[0155] Finally, it should be noted that the above-described embodiments are only specific implementation methods of the present disclosure, which are used to illustrate the technical solutions of the present disclosure, rather than to limit them. The protection scope of the present disclosure is not limited thereto. Although the present disclosure is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed in the present disclosure, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present disclosure, and should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A power battery heating method, characterized in that: Applied to a power system, the power system comprising a power battery, a drive motor, and an inverter connected between the power battery and the drive motor; The inverter includes a three-phase full-bridge inverter circuit; the method includes: In response to satisfying a heating condition for the power battery, detecting a position of a motor rotor of the drive motor; Determining a target winding from the three-phase windings according to a relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor; The three-phase full-bridge inverter circuit is controlled to work alternately in three cycles to generate a heating current on the busbar of the power battery. In each cycle, the phase currents of the other two phase windings of the three-phase winding except the target winding flow in, and the phase current of the target winding flows out.

2. The method according to claim 1, characterized in that The two ends of the power battery are connected to bus capacitors; the three cycles include a first cycle, a second cycle and a third cycle; the three-phase full-bridge inverter circuit is controlled to work alternately according to the three cycles, including: In the first cycle, the three-phase full-bridge inverter circuit is controlled to operate in a first operating mode, so as to control the power battery to charge the bus capacitor and the three-phase winding; In the second period, the three-phase full-bridge inverter circuit is controlled to operate in the second operating mode, so that the bus capacitor releases energy to charge the power battery, and the phase currents of the three-phase windings form an internal circulation current; the internal circulation current refers to the phase current flowing out of the target winding, then flowing into the other two-phase windings and continuing to flow out of the target winding; In the third period, the three-phase full-bridge inverter circuit is controlled to operate in a third operating mode so that the three-phase winding charges the power battery and the bus capacitor.

3. The method according to claim 1, characterized in that The amplitude direction of the phase current corresponding to the target winding is opposite to the amplitude direction of the phase current corresponding to the other two-phase windings, and the phase current corresponding to each phase winding is a half-wave current; the three cycles include a first cycle, a second cycle and a third cycle; In the first cycle, the amplitude of the phase current of each phase winding increases gradually according to the first slope to the corresponding first preset current; In the second period, the amplitude of the phase current of each phase winding decreases from the first preset current to the corresponding second preset current according to a second slope, and the second slope is smaller than the first slope; In the third period, the amplitude of the phase current of each phase winding decreases from the second preset current to the corresponding third preset current according to a third slope, and the third slope is greater than the second slope.

4. The method according to claim 1, characterized in that: The three cycles form a heating period cycle, and the three heating period cycles constitute a heating cycle. The method further includes: The power battery is pulse heated according to the heating cycle; in each heating cycle, the target windings corresponding to the three heating time periods are different.

5. The method according to claim 2, characterized in that: The midpoint of each bridge arm in the three-phase full-bridge inverter circuit is respectively connected to a phase winding; in the second period, controlling the three-phase full-bridge inverter circuit to operate in the second operating mode includes: In the second period, the upper bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned on, and the lower bridge arm of each bridge arm in the three-phase full-bridge inverter circuit is controlled to be turned off.

6. The method according to claim 5, characterized in that In the first cycle, controlling the three-phase full-bridge inverter circuit to operate in a first operating mode includes: In the first cycle, the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned on, and the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned off; and / or, In the third period, controlling the three-phase full-bridge inverter circuit to operate in the third operating mode includes: In the third cycle, the lower bridge arms corresponding to the other two-phase windings and the upper bridge arms corresponding to the target winding are controlled to be turned on, and the upper bridge arms corresponding to the other two-phase windings and the lower bridge arms corresponding to the target winding are controlled to be turned off.

7. The method according to claim 1, characterized in that The step of determining a target winding from the three-phase windings according to the relative position relationship between the position of the motor rotor and each winding in the three-phase windings of the drive motor comprises: Determine the angle between the motor rotor and each phase winding of the three-phase winding; The winding whose angle with the motor rotor is within a preset angle range is determined as the target winding; the preset angle range includes a first preset angle range and a second preset angle range, the first preset angle range is -30° to 30°, and the second preset angle range is -150° to 210°.

8. The method according to claim 7, characterized in that The method further comprises: If the angle between the motor rotor and the target winding is within the first preset angle range, controlling the drive motor to rotate so that the angle between the motor rotor and the target winding is 0°; If the angle between the motor rotor and the target winding is within the second preset angle range, the drive motor is controlled to rotate so that the angle between the motor rotor and the target winding is 180°.

9. A motor controller, characterized in that: include: a memory configured to store instructions; as well as A processor is configured to call the instruction from the memory and implement the power battery heating method according to any one of claims 1 to 8 when executing the instruction.

10. A power system, characterized in that: It includes a power battery, an inverter, a drive motor and the motor controller as described in claim 9, the DC side of the inverter is connected to the power battery, the AC side of the inverter is connected to the drive motor, and the power battery, the inverter and the drive motor are all connected to the motor controller.

11. An electric vehicle, characterized in that: Comprising a power system according to claim 10.

12. A computer program product, characterized in that It comprises a computer program, and when the computer program is executed by a computer device or a processor, the computer device or the processor executes the power battery heating method according to any one of claims 1 to 8.

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