A control method for a battery self-heating system

Abstract

The present invention relates to a control method for a battery self-heating system, the control method comprising: obtaining the rotor position of a permanent magnet synchronous motor; selecting at least three control points from preset space voltage vector points, wherein the control points include a space voltage vector closest to the magnetic pole spacing of the motor rotor; and determining multiple phase states of an inverter corresponding to the control points from a preset space voltage vector control table. Based on the control of the space voltage vector, the current circulation inside the three-phase winding of the motor is reduced, the bus current is increased, and thus the battery heating rate is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a control method for a battery self-heating system. Background Art

[0002] The battery's charging and discharging performance drops significantly in low-temperature environments, its lifespan is reduced, and it is prone to lithium precipitation, leading to safety risks such as fire and explosion. In order to improve low-temperature performance, the charging and discharging batteries need to be heated in low-temperature environments. The current mainstream battery heating technologies include liquid cooling pipe heating, heating film heating, etc. The heating rate is slow, and it is prone to failures due to excessive temperature differences, leading to customer complaints. The relevant patent outputs the three-phase alternating current output by the motor in a predetermined current cycle loading mode, and the current circulates inside the three-phase winding of the motor, which also has the problem of slow battery heating efficiency. Summary of the invention

[0003] The present invention provides a control method for a battery self-heating system to solve the problem of slow battery self-heating rate.

[0004] An embodiment of the present invention provides a control method for a battery self-heating system, the control method comprising: obtaining a permanent magnet synchronous motor rotor position; selecting at least three control points from preset space voltage vector points, wherein the control points include the space voltage vector closest to the magnetic pole spacing of the motor rotor; determining a plurality of phase states of an inverter corresponding to the control points from a preset space voltage vector control table; and sending a control instruction to a motor controller based on the phase state, so that the inverter switches sequentially between the plurality of phase states.

[0005] Further, selecting at least three control points from preset space voltage vector points includes: selecting three control points from preset space voltage vector points.

[0006] Further, the selecting three control points from the preset space voltage vector points includes: selecting three control points spaced apart from each other from the preset space voltage vector points.

[0007] Further, selecting at least three control points from preset space voltage vector points includes: selecting four control points from preset space voltage vector points.

[0008] Further, selecting at least one pair of relative points from the preset space voltage vector points includes: selecting two pairs of relative points from the preset space voltage vector points.

[0009] Further, sending a control instruction to a motor controller based on the phase state so that the inverter switches sequentially between the plurality of phase states comprises: selecting two pairs of relative points and switching them sequentially.

[0010] Further, the selecting two pairs of relative points to switch in sequence includes: the two pairs of relative points are switched in sequence, wherein control points when the two pairs of relative points are switched are adjacent points.

[0011] Further, selecting at least three control points from preset space voltage vector points includes: selecting six control points from preset space voltage vector points.

[0012] Furthermore, sending a control instruction to a motor controller based on the phase state so that the inverter switches sequentially between the plurality of phase states comprises: selecting six control points and switching them sequentially at intervals.

[0013] Furthermore, the selecting six control points and switching them sequentially at intervals includes: the six control points are three pairs, the three pairs of relative points are switched sequentially, and the control points when any two pairs of relative points are switched are adjacent points.

[0014] The embodiment of the present invention provides a control method for a battery self-heating system, the control method comprising: obtaining the rotor position of a permanent magnet synchronous motor; selecting at least three control points from preset spatial voltage vector points, wherein the control points include a spatial voltage vector closest to the magnetic pole spacing of the motor rotor; determining multiple phase states of the inverter corresponding to the control points from a preset spatial voltage vector control table; sending a control instruction to the motor controller based on the phase state, so that the inverter switches between multiple phase states in sequence. The high-frequency self-heating technology of the battery cell is utilized, a high-frequency current is generated through the motor controller, and the impedance characteristics of the battery cell under high-frequency AC current are utilized to achieve self-heating. Based on the control of the spatial voltage vector, the current circulation inside the three-phase winding of the motor is reduced, the bus current is increased, and thus the battery heating rate is increased. At the same time, the existing components are fully utilized to reduce the cost of heating accessories for the whole vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention;

[0016] Figure 2 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0017] Figure 3 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0018] Figure 4 A three-space voltage vector diagram provided by an embodiment of the present invention;

[0019] Figure 5A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0020] Figure 6 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0021] Figure 7 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0022] Figure 8 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0023] Fig. 9 A four-space voltage vector diagram provided by an embodiment of the present invention;

[0024] Fig.10 A schematic flow chart of another battery self-heating system control method provided by an embodiment of the present invention;

[0025] Fig.11 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0026] Fig.12 A schematic flow chart of another method for controlling a battery self-heating system provided by an embodiment of the present invention;

[0027] Fig.13 A six-space voltage vector diagram provided by an embodiment of the present invention;

[0028] Fig.14 A schematic structural diagram of an optimization system for a battery self-heating system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0030] The various specific technical features described in the specific embodiments can be combined in any suitable manner without contradiction, for example, different embodiments and technical solutions can be formed by combining different specific technical features. In order to avoid unnecessary repetition, various possible combinations of the specific technical features in the present invention will not be described separately.

[0031] In the following description, the terms "first\second\..." are only used to distinguish different objects, and do not mean that the objects have the same or related points. It should be understood that the directions "above", "below", "outside" and "inside" are all directions in normal use, and the directions "left" and "right" refer to the left and right directions shown in the corresponding schematic diagrams, which may or may not be the left and right directions in normal use.

[0032] It should be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. The term "connected" includes both direct and indirect connections unless otherwise specified.

[0033] The control method of the battery self-heating system provided in the specific implementation is applicable to any different types of electric vehicles. For example, the control method of the battery self-heating system is applicable to the battery self-heating of pure electric vehicles; for example, the control method of the battery self-heating system is applicable to the battery self-heating of hybrid vehicles. Similarly, the control method of the battery self-heating system is applicable to vehicles of different specifications and types. For example, the control method of the battery self-heating system is applicable to the battery self-heating of household pure electric cars; for example, the control method of the battery self-heating system is applicable to the battery self-heating of commercial pure electric buses; for the sake of convenience, the following is an example of the control method for the battery self-heating of household pure electric cars.

[0034] In some embodiments, see Figure 1 , Figure 1 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the process of the control method includes:

[0035] Step S1, obtaining the rotor position of the permanent magnet synchronous motor.

[0036] It should be noted that the specific position of the permanent magnet synchronous motor rotor in the motor is obtained by using the control system. Any method that can obtain the position of the permanent magnet synchronous motor rotor meets the requirements of this case. For example, the motor is provided with a position sensor, and the position sensor is used to obtain the position of the permanent magnet synchronous motor rotor. It should be noted that the permanent magnet synchronous motor is mainly composed of various components such as the rotor, the end cover and the stator. The starting and operation of the permanent magnet synchronous motor are formed by the interaction of the magnetic fields generated by the stator winding, the rotor cage winding and the permanent magnet. When the motor is stationary, a three-phase symmetrical current is passed through the stator winding to generate a stator rotating magnetic field. The stator rotating magnetic field rotates relative to the rotor to generate current in the cage winding to form a rotor rotating magnetic field. The asynchronous torque generated by the interaction between the stator rotating magnetic field and the rotor rotating magnetic field causes the rotor to accelerate from stationary. In this process, the rotor permanent magnetic field and the stator rotating magnetic field have different speeds, which will generate alternating torque. When the rotor accelerates to a speed close to the synchronous speed, the speeds of the rotor permanent magnetic field and the stator rotating magnetic field are close to equal, and the speed of the stator rotating magnetic field is slightly greater than that of the rotor permanent magnetic field. They interact to generate torque to pull the rotor into a synchronous operation state. In the synchronous operation state, no current is generated in the rotor winding. At this time, only the permanent magnets on the rotor generate a magnetic field, which interacts with the stator rotating magnetic field to generate a driving torque.

[0037] Step S2: selecting at least three control points from preset space voltage vector points, wherein the control points include a space voltage vector closest to the magnetic pole spacing of the motor rotor.

[0038] It should be noted that the voltage, current, flux and other physical quantities of the AC motor windings are all time-varying. The space voltage vector, like the space current vector and flux vector, is a type of control vector for the variable frequency speed regulation system. The space voltage vector is based on the overall generation effect of the three-phase waveform, with the purpose of approaching the ideal circular rotating magnetic field trajectory of the motor air gap, generating a three-phase modulation waveform at a time, and controlling it in the way of approximating the circle by an inscribed polygon. The axis of the three-phase winding of the motor stator is 120 degrees apart in space. The three-phase stator sinusoidal phase voltage is applied to the three-phase winding respectively. Three stator space voltage vectors are defined so that their directions are always on the axis of each phase winding, and the magnitude fluctuates according to the sine law over time. The time phase is staggered by 120 degrees. The upper and lower bridge arm switches of each phase of the three-phase inverter circuit are opposite, so the three-phase inverter circuit corresponds to eight output voltage states, including six effective working vectors and two zero vectors. Therefore, the working state of the inverter is only switched six times in one cycle, corresponding to the formation of six space voltage vectors.

[0039] For ease of explanation, the six spatial voltage vectors are referred to as six spatial voltage vector points V1, V2, V3, V4, V5 and V6. The six spatial voltage vector points are evenly distributed. Any two adjacent points are connected to the center point, and the angle formed is 60 degrees. At least three control points are selected from the preset spatial voltage vector points. Specifically, it can be understood that at least three spatial voltage vectors are selected from the preset six spatial voltage vectors and applied to the three-phase winding of the motor. For example, using battery self-heating based on three spatial voltage vectors, select three spatial voltage vectors of V1, V2 and V4 to apply to the three-phase winding of the motor. For example, using battery self-heating based on four spatial voltage vectors, select four spatial voltage vectors of V1, V3, V4 and V6 to apply to the three-phase winding of the motor. For example, using battery self-heating based on six spatial voltage vectors, select six spatial voltage vectors of V1, V2, V3, V4, V5 and V6 to apply to the three-phase winding of the motor. The schemes for different space voltage vectors will be described in detail below, wherein the control points include the space voltage vector closest to the magnetic pole spacing of the motor rotor, where the closest can be understood as the closest to the magnetic pole of the motor rotor among the six space voltage vectors, and specifically can be understood as the space voltage vector closest to the magnetic pole of the motor rotor when the space voltage vector is selected to be applied to the three-phase winding of the motor. For example, if the extension direction of the N pole of the magnetic pole of the motor rotor is directly opposite to V1, then V1 belongs to one of the selected control points, that is, V1 is one of the output space voltage vectors.

[0040] Step S3: determining multiple phase states of the inverter corresponding to the control point from a preset space voltage vector control table.

[0041] Specifically, the motor inverter has six switches Q1, Q2, Q3, Q4, Q5 and Q6, each of which includes an IGBT (Insulated Gate Bipolar Transistor) module, and a space voltage vector is generated by the on-off combination of the six switches of the inverter. Secondly, from the preset space voltage vector control table, the control table here can be understood as a table that summarizes the control method of the space voltage vector generated by the on-off combination of the six switches of the inverter, and how the on-off combination of the six switches of the specific inverter corresponds to the space voltage vector, for example, turn on switches Q1, Q6 and Q2, turn off switches Q4, Q3 and Q5, then output space voltage vector V1, turn on switches Q4, Q3 and Q2, turn off switches Q1, Q6 and Q5, then output space voltage vector V2, which belongs to the existing conventional technology and will not be described in detail. And the control table is entered into the control system. The multiple phase states of the inverter corresponding to the control point can be understood as each space voltage vector corresponds to a different on-off combination of the six switches of the inverter. The specific operating principle can be understood as follows: for the space voltage vector that needs to be output, the control system queries the space voltage vector control table to determine the on-off combination state of the six switches of the inverter. For example, if the space voltage vector V1 needs to be output, the six switches of the inverter are determined to turn on switches Q1, Q6 and Q2, and turn off switches Q4, Q3 and Q5.

[0042] Step S4: sending a control instruction to the motor controller based on the phase state, so that the inverter switches between multiple phase states in sequence.

[0043] Specifically, for the space voltage vector to be output, the control system queries the space voltage vector control table to determine the on-off combination state of the six switches of the inverter, and then adjusts the on-off combination state of the six switches of the inverter in sequence according to the order of the space voltage vector to be output, so that the inverter switches between multiple phase states in sequence. It should be noted that after the output order of the space voltage vector is determined within a cycle, it will be cycled according to the previously set output order in the later stage, and the output order of the space voltage vector will no longer be adjusted. For example, if the output order of the space voltage vector is V1, V2, V4, then it will be cycled according to V1, V2, V4, V1, V2, V4, V1, V2, V4... in the later stage. Secondly, a certain time can be spaced between the switching of the space voltage vector, and the interval time can be the same as the output time of the space voltage vector, or it can be different. Each interval time needs to be consistent, and each space voltage vector output time needs to be consistent. The specific interval time and the space voltage vector output time are not specifically limited.

[0044] The embodiment of the present invention provides a control method for a battery self-heating system, the control method comprising: obtaining the rotor position of a permanent magnet synchronous motor; selecting at least three control points from preset spatial voltage vector points, wherein the control points include a spatial voltage vector closest to the magnetic pole spacing of the motor rotor; determining multiple phase states of the inverter corresponding to the control points from a preset spatial voltage vector control table; sending a control instruction to the motor controller based on the phase state, so that the inverter switches between multiple phase states in sequence. The high-frequency self-heating technology of the battery cell is utilized, a high-frequency current is generated through the motor controller, and the impedance characteristics of the battery cell under high-frequency AC current are utilized to achieve self-heating. Based on the control of the spatial voltage vector, the current circulation inside the three-phase winding of the motor is reduced, the bus current is increased, and thus the battery heating rate is increased. At the same time, the existing components are fully utilized to reduce the cost of heating accessories for the whole vehicle.

[0045] In some embodiments, in combination Figure 2 and Figure 4 As shown, Figure 2 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 1 , Figure 2 Step S2 in the method comprises:

[0046] Step S21 : selecting three control points from preset spatial voltage vector points.

[0047] Specifically, based on the three spatial voltage vectors, three control points are selected from the six spatial voltage vectors, that is, three spatial voltage vectors are selected, wherein the control points include the spatial voltage vector closest to the magnetic pole spacing of the motor rotor. Specifically, it can be understood that the angle between the N-pole extension direction of the motor rotor and the line connecting the center of the motor rotor and V1 is within plus or minus 30 degrees, including 30 degrees, which can be understood as the N-pole of the motor rotor is located near V1, that is, the spatial voltage vector closest to the magnetic pole spacing of the motor rotor is V1. The three control points are selected from the preset spatial voltage vector points, which can be any combination. For example, the spatial voltage vector closest to the magnetic pole spacing of the motor rotor is V1, and the three spatial voltage vectors can be V1, V3, V2, or V1, V2, V4, without specific limitation.

[0048] In some embodiments, in order to reduce the current circulation inside the three-phase winding of the motor and increase the bus current, Figure 3 and Figure 4 As shown, Figure 3 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 2 , Figure 3 Step S21 in the embodiment includes:

[0049] Step S211: select three control points at intervals from the preset spatial voltage vector points.

[0050] Specifically, based on the three spatial voltage vectors, three control points are selected from the six spatial voltage vectors, that is, three spatial voltage vectors are selected, and the three spatial voltage vectors are V1, V2, V4 or V3, V6, V5. Exemplarily, the angle between the N-pole extension direction of the motor rotor and the line connecting the motor rotor center and V1 is within plus or minus 30 degrees, including 30 degrees, which can be understood as the N-pole of the motor rotor is located near V1, that is, the spatial voltage vector closest to the magnetic pole spacing of the motor rotor is V1, and the three selected spatial voltage vectors are V1, V2, and V4. Similarly, the N-pole of the motor rotor is located near V2 and V4, and the three selected spatial voltage vectors are also V1, V2, and V4. Exemplarily, the angle between the N-pole extension direction of the motor rotor and the line connecting the motor rotor center and V3 is within plus or minus 30 degrees, including 30 degrees, which can be understood as the N-pole of the motor rotor is located near V3, that is, the space voltage vector closest to the magnetic pole spacing of the motor rotor is V3, and the three selected space voltage vectors are V3, V6, and V5. Similarly, the N-pole of the motor rotor is located near V5 and V6, and the three selected space voltage vectors are also V3, V6, and V5.

[0051] Use three space voltage vectors V1, V2 and V4 or V3, V5 and V6 to apply to the three-phase winding of the motor. The application time of each space voltage vector is consistent. The order of applying each space voltage vector is arbitrary, but it is always applied in this order during the cycle to obtain the corresponding current response. For example, Figure 4 As shown, taking the motor rotor position near V1 as an example, a battery self-heating control method based on three-space voltage vectors is provided. This method includes:

[0052] The first step is to output the space voltage vector V1, and the application time is t1;

[0053] The second step is to not output any space voltage vector for a period of time;

[0054] The third step is to output the spatial voltage vector V2, and the application time is t2;

[0055] Step 4: Do not output any space voltage vector for a period of time;

[0056] Step 5: Output the space voltage vector V4, and apply it for a time of t4;

[0057] Step 6: Do not output any space voltage vector for a period of time; repeat steps 1 to 6. It should be noted that the application time is equal, that is, t1=t2=t4, each interval time needs to be consistent, each space voltage vector output time needs to be consistent, and the specific interval maintenance time between two output space voltage vectors and the space voltage vector output time t1, t2, t4 are not specifically limited.

[0058] In some embodiments, in combination Figure 5 and Fig. 9 As shown, Figure 5 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 1 , Figure 2 Step S2 in the method further comprises:

[0059] Step S22: Select four control points from the preset spatial voltage vector points.

[0060] Specifically, based on the four spatial voltage vectors, four control points are selected from the six spatial voltage vectors, that is, four spatial voltage vectors are selected, wherein the control points include the spatial voltage vector closest to the magnetic pole spacing of the motor rotor. Specifically, it can be understood that, for example, the N-pole extension direction of the motor rotor is in the angle between the line connecting the motor rotor center and V1 and the line connecting the motor rotor center and V3, that is, the spatial voltage vectors closest to the magnetic pole spacing of the motor rotor are V1 and V3. Four control points are selected from the preset spatial voltage vector points, which can be any combination and must include V1 and V3. For example, the spatial voltage vectors closest to the magnetic pole spacing of the motor rotor are V1 and V3. The four spatial voltage vectors can be V1, V3, V2 and V6, or V1, V3, V4 and V6 are not specifically limited.

[0061] In some embodiments, in order to reduce the current circulation inside the three-phase winding of the motor and increase the bus current, Figure 6 and Fig. 9 As shown, Figure 6 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 5 , Figure 6 Step S22 in the embodiment includes:

[0062] Step S221 : Select two pairs of relative points from preset spatial voltage vector points.

[0063] Specifically, based on the four space voltage vectors, four control points are selected from the six space voltage vectors, that is, four space voltage vectors are selected, and the four space voltage vector points are two pairs of relative points. The relative points can be specifically understood as the control points where the corresponding voltage vectors in the space voltage vector control table are located on the same straight line and in opposite directions. Specifically, V1 and V6 are relative points, V3 and V4 are relative points, and V2 and V5 are relative points. Exemplarily, the N-pole extension direction of the motor rotor is in the angle between the line connecting the motor rotor center and V1 and the line connecting the motor rotor center and V3, and the four space voltage vector points are V1, V3, V6 and V4. Exemplarily, the N-pole extension direction of the motor rotor is in the angle between the line connecting the motor rotor center and V3 and the line connecting the motor rotor center and V2, and the four space voltage vector points are V3, V4, V2 and V5.

[0064] In some embodiments, in combination Figure 7 and Fig. 9 As shown, Figure 7 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 6 , Figure 7 Step S4 in the method comprises:

[0065] Step S41, select two pairs of relative points and switch them in sequence.

[0066] Specifically, for the sake of convenience, four spatial voltage vectors, V1, V6, V4 and V3, are applied to the three-phase winding of the motor. The application time of each spatial voltage vector remains consistent. Selecting two pairs of relative points and switching in sequence includes two situations. First, the application order of each spatial voltage vector is any vector of the above four spatial vectors, relative vector, adjacent vector, and the relative vector of the adjacent vector is the reference point in sequence, that is, the order of V1, V6, V3, and V4; second, the application order of each spatial voltage vector is any vector of the above four spatial vectors, relative vector, adjacent vector of the relative vector, adjacent vector, and the reference point in sequence, that is, the order of V1, V6, V4, and V3; each time it is applied, no vector is output for a period of time, and the time is adjustable. It must always be applied in this order during the cycle to obtain the corresponding current response.

[0067] In some embodiments, in combination Figure 8 and Fig. 9 As shown, Figure 8 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 7 , Figure 8 Step S41 in the embodiment includes:

[0068] Step S411, two pairs of relative points are switched in sequence, wherein the control points when the two pairs of relative points are switched are adjacent points.

[0069] Specifically, also for the sake of convenience, four spatial voltage vectors V1, V6, V4 and V3 are applied to the three-phase winding of the motor. Four spatial voltage vectors V1, V6, V4 and V3 are applied to the three-phase winding of the motor. The application time of each spatial voltage vector remains consistent. The application order of each spatial voltage vector is any vector of the above four spatial vectors, the relative vector, the adjacent vector of the relative vector, and the adjacent vectors are the reference points, i.e., the order of V1, V6, V4, and V3; each time it is applied, no vector is output for a period of time, and the time is adjustable. It must always be applied in this order during the cycle to obtain the corresponding current response. For example, Fig. 9 As shown, taking the motor rotor position between V1 and V3 as an example, a battery self-heating control method based on four-space voltage vectors is provided. This method includes:

[0070] The first step is to output the space voltage vector V1, and the application time is t1, which is adjustable;

[0071] The second step is to not output any space voltage vector for a period of time;

[0072] Step 3: Output the space voltage vector V6, and apply it for a time of t6;

[0073] Step 4: Do not output any space voltage vector for a period of time;

[0074] Step 5: Output the space voltage vector V4, and apply it for a time of t4;

[0075] Step 6: Do not output any space voltage vector for a period of time;

[0076] Step 7: Output the space voltage vector V3, and the application time is t3;

[0077] Step 8: Do not output any space voltage vector for a period of time;

[0078] Repeat the first step to the eighth step. It should be noted that the application time is equal, that is, t1 = t3 = t4 = t6. Each interval time needs to be consistent, and each space voltage vector output time needs to be consistent. The specific interval maintenance time between two output space voltage vectors and the space voltage vector output time t1, t3, t4, t6 are not specifically limited.

[0079] In some embodiments, in combination Fig.10 and Fig.13 As shown, Fig.10 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Figure 1 , Figure 2 Step S2 in the method further comprises:

[0080] Step S23: Select six control points from the preset spatial voltage vector points.

[0081] Specifically, based on the six space voltage vectors, six control points are selected from the six space voltage vectors, that is, all six space voltage vectors are selected.

[0082] In some embodiments, in combination Fig.11 and Fig.13 As shown Fig.11 As shown, Fig.11 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Fig.10 , Fig.11 Step S4 in the method comprises:

[0083] Step S42: Select six control points and switch them in sequence.

[0084] Specifically, for ease of explanation, six space voltage vectors V1, V2, V3, V4, V5 and V6 are applied to the three-phase winding of the motor. The application time of each space voltage vector is kept consistent. Selecting six control points to switch in sequence at intervals can be switching in sequence at any intervals. For example, the reference points can be in the order of V1, V6, V5, V3, V4, V2; for example, the reference points can also be in the order of V1, V6, V3, V4, V2, V5; each time it is applied, no vector is output for a period of time, and the time is adjustable. It must always be applied in this order during the cycle to obtain the corresponding current response.

[0085] In some embodiments, in combination Fig.12 and Fig.13 As shown, Fig.12 A flow chart of a control method for a battery self-heating system provided by an embodiment of the present invention, based on Fig.11 , Fig.12 Step S42 in includes:

[0086] Step S421, the six control points are divided into three pairs, and the three pairs of relative points are switched in sequence, wherein the control points when any two pairs of relative points are switched are adjacent points.

[0087] Specifically, six spatial voltage vectors V1, V2, V3, V4, V5 and V6 are applied to the three-phase winding of the motor. The application time of each spatial voltage vector remains consistent. The six control points are divided into three pairs, V1 and V6, V3 and V4, V2 and V5. The order of application of each spatial voltage vector is any vector, a relative vector, another pair of vectors and their relative vectors, and the last pair of vectors and their relative vectors. That is, each pair of vectors must be output within a cycle, and the vectors when switching between two pairs of vectors are adjacent vectors, which are reference points in sequence, namely, V1, V6, V2, V5, V4, and V3; each time an application is performed, no vector is output for a period of time, and the time is adjustable. It is necessary to always apply in this order during the cycle to obtain the corresponding current response. For example, Fig.13 As shown, taking the motor rotor position between V1 and V3 as an example, a battery self-heating control method based on six-space voltage vectors is provided. This method includes:

[0088] The first step is to output the space voltage vector V1, and the application time is t1, which is adjustable;

[0089] The second step is to not output any space voltage vector for a period of time;

[0090] Step 3: Output the space voltage vector V6, and apply it for a time of t6;

[0091] Step 4: Do not output any space voltage vector for a period of time;

[0092] Step 5: Output the space voltage vector V2, and the application time is t2;

[0093] Step 6: Do not output any space voltage vector for a period of time;

[0094] Step 7: Output the space voltage vector V5, and apply it for a time of t5;

[0095] Step 8: Do not output any space voltage vector for a period of time;

[0096] Step 9: output the space voltage vector V4, and the application time is t4;

[0097] Step 10: Do not output any space voltage vector for a period of time;

[0098] Step 11: output the space voltage vector V3, and the application time is t3;

[0099] Step 12: Do not output any space voltage vector for a period of time;

[0100] Repeat step 1 to step 12. It should be noted that the application time is equal, that is, t1 = t2 = t3 = t4 = t5 = t6. Each interval time needs to be consistent, and each space voltage vector output time needs to be consistent. The specific interval maintenance time between two output space voltage vectors and the space voltage vector output time t1, t2, t3, t4, t5, t6 are not specifically limited.

[0101] The embodiment of the present invention also provides an optimization system for a battery self-heating system, such as Fig.14 As shown, the optimization system includes: an acquisition module 100 and a processing module 200. The acquisition module 100 is used to acquire the rotor position of the permanent magnet synchronous motor. The processing module 200 selects at least three control points from the preset space voltage vector points. The processing module 200 is also used to determine multiple phase states of the inverter corresponding to the control points from the preset space voltage vector control table; the processing module 200 also sends a control instruction to the motor controller based on the phase state, so that the inverter switches between multiple phase states in sequence.

[0102] In some embodiments, Fig.14 As shown, the acquisition module 100 selects three control points from the preset space voltage vector points. In some embodiments, the acquisition module 100 selects three control points at intervals from the preset space voltage vector points.

[0103] In some embodiments, Fig.14 As shown, the acquisition module 100 selects four control points from the preset space voltage vector points. In some embodiments, the acquisition module 100 selects at least one pair of relative points from the preset space voltage vector points, wherein the relative points are control points whose corresponding voltage vectors in the space voltage vector control table are located on the same straight line and in opposite directions. In some embodiments, the acquisition module 100 selects two pairs of relative points from the preset space voltage vector points. In some embodiments, the processing module 200 is used to select two pairs of relative points and switch them in sequence. In some embodiments, the processing module 200 is also used to switch two pairs of relative points in sequence, wherein the control points when switching the two pairs of relative points are adjacent points.

[0104] In some embodiments, Fig.14 As shown, the acquisition module 100 selects six control points from the preset spatial voltage vector points. In some embodiments, the processing module 200 is further used to select the six control points and switch them in sequence. In some embodiments, the six control points are three pairs, and the processing module 200 is further used to switch the three pairs of relative points in sequence, wherein the control points when any two pairs of relative points are switched are adjacent points.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A control method for a battery self-heating system, characterized in that: The control method comprises: Get the rotor position of the permanent magnet synchronous motor; Selecting at least three control points from preset space voltage vector points, wherein the control points include the space voltage vector closest to the magnetic pole spacing of the motor rotor; Determining a plurality of phase states of the inverter corresponding to the control point from a preset space voltage vector control table; A control instruction is sent to a motor controller based on the phase state, so that the inverter switches between the plurality of phase states in sequence.

2. The control method according to claim 1, characterized in that: The selecting at least three control points from the preset spatial voltage vector points comprises: Select three control points from the preset spatial voltage vector points.

3. The control method according to claim 2, characterized in that: The selecting three control points from the preset space voltage vector points includes: Three control points are selected at intervals from the preset spatial voltage vector points.

4. The control method according to claim 1, characterized in that: The selecting at least three control points from the preset spatial voltage vector points comprises: Select four control points from the preset spatial voltage vector points.

5. The control method according to claim 4, characterized in that: The selecting at least one pair of relative points from the preset spatial voltage vector points comprises: Two pairs of relative points are selected from the preset spatial voltage vector points.

6. The control method according to claim 5, characterized in that: The sending of a control instruction to the motor controller based on the phase state so that the inverter switches sequentially between the plurality of phase states comprises: The two pairs of relative points are selected and switched in sequence.

7. The control method according to claim 6, characterized in that: The selecting two pairs of relative points to switch in sequence comprises: The two pairs of relative points are switched in sequence, wherein the control points when the two pairs of relative points are switched are adjacent points.

8. The control method according to claim 1, characterized in that: The selecting at least three control points from the preset spatial voltage vector points comprises: Six control points are selected from the preset spatial voltage vector points.

9. The control method according to claim 8, characterized in that: The sending of a control instruction to the motor controller based on the phase state so that the inverter switches sequentially between the plurality of phase states comprises: The six control points are selected and switched in sequence at intervals.

10. The control method according to claim 9, characterized in that: The selecting six control points to be switched sequentially at intervals comprises: The six control points are divided into three pairs, and the three pairs of relative points are switched in sequence, wherein the control points when any two pairs of relative points are switched are adjacent points.

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