A control method of a power system, a power system, a medium and a new energy vehicle

Abstract

This invention discloses a control method for a power system, a power system, a medium, and a new energy vehicle. The method includes: collecting current operating parameters of a motor; obtaining a reference stator current from a pre-constructed motor current condition table using the current operating parameters, and controlling the motor operation using the reference stator current; wherein the motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under these three dimensions; obtaining a reference frequency from a pre-constructed switching frequency condition table using the current operating parameters, and controlling the switching on and off of the switching device using the reference frequency; wherein the switching frequency condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves a preset system efficiency of the power system under these three dimensions.

Description

Technical Field

[0001] This application relates to vehicle control technology, and more particularly to a control method for a power system, a power system, a medium, and a new energy vehicle. Background Technology

[0002] Due to the increasingly severe energy and environmental situation, traditional gasoline-powered vehicles are trending towards being replaced by new energy vehicles.

[0003] While new energy vehicles have advantages such as good environmental performance and smooth operation, they also suffer from range anxiety due to the severe reduction in range caused by low-temperature environments and the limited charging time and infrastructure.

[0004] To alleviate range anxiety in new energy vehicles, existing technologies mostly focus on improvements to the power battery. As is well known, the power system of a new energy vehicle, besides the power battery as energy storage, also includes the motor and controller as the power source, such as a permanent magnet synchronous motor. However, there is currently no precedent for improving the efficiency of the power system from the control level of the motor and controller. Summary of the Invention

[0005] This invention provides a control method for a power system, a power system, a medium, and a new energy vehicle. By comprehensively considering controller losses and motor losses, the switching frequency and motor current under different operating conditions are adjusted to improve the overall efficiency of the power system, thus filling the gap that cannot improve the efficiency of the power system from the control level of the motor and controller.

[0006] To address the aforementioned technical problems, a first aspect of the present invention discloses a control method for a power system, the power system comprising a power battery, a motor controller, and a motor, wherein the motor controller includes a transfer switch for converting the direct current (DC) power from the power battery into alternating current (AC) power to supply the motor; the method includes:

[0007] Collect the current operating parameters of the motor;

[0008] The reference stator current is obtained from a pre-built motor current condition table using the current operating parameters of the motor, and the motor operation is controlled using the reference stator current; wherein, the motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under the three dimensions;

[0009] The reference frequency is obtained from a pre-constructed switching frequency operating condition table using the current operating parameters of the motor, and the switching on and off of the switching is controlled by the reference frequency; wherein, the switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves the preset system efficiency of the power system under the three dimensions.

[0010] Optionally, the motor current condition table is constructed in the following manner:

[0011] Under the constraint of motor voltage, determine P motor speed operating points and M motor output torque operating points; wherein, the motor voltage is one of the following: minimum operating voltage, rated operating voltage, maximum operating voltage; the selection range of the P motor speed operating points is (0, N). max ), N max This indicates the maximum operating speed; the selection range for the output torque operating points of the M motors is (0, T). e-max ), T e-max This represents the maximum torque; P≥1, M≥1 and both are positive integers;

[0012] When the motor speed reaches any of the P motor speed operating points, the motor stator current is adjusted in combination with the first control target or the second control target to achieve M motor output torque operating points, and the minimum stator current corresponding to each of the M motor output torque operating points is obtained; the first control target is: to adjust the motor output torque operating point using the minimum stator current, and the second control target is: to adjust the motor output torque operating point using the minimum stator current under voltage limitation;

[0013] Based on the motor voltage, the P motor speed operating points, the M motor output torque operating points, and the regulated minimum stator current, the motor current operating condition table is constructed; wherein, the minimum stator current includes the current module and angle.

[0014] Optionally, the motor current condition table may specifically be: a motor current condition table corresponding to the minimum operating voltage, a motor current condition table corresponding to the rated operating voltage, and a motor current condition table corresponding to the maximum operating voltage.

[0015] Optionally, the current operating parameters of the motor include: current actual voltage, current actual speed, and current actual torque;

[0016] The step of obtaining the reference stator current from a pre-built motor current condition table using the current operating parameters of the motor specifically includes:

[0017] Determine whether the current actual voltage is one of the following: the minimum operating voltage, the rated operating voltage, or the maximum operating voltage;

[0018] If so, based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage, determine the target motor current condition table; based on the current actual speed and / or the current actual torque, obtain the reference stator current from the target motor current condition table;

[0019] If not, based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage, two target motor current condition tables are selected according to the voltage approximation principle; with reference to the current actual voltage, the current actual speed, and the current actual torque, the reference stator current is calculated by interpolation from the two target motor current condition tables.

[0020] Optionally, the switching frequency operating condition table is constructed in the following manner:

[0021] Under the constraints of the motor voltage, the P motor speed operating points, and the M motor output torque operating points, the switching frequency is adjusted to achieve the preset system efficiency; the preset system efficiency includes the maximum system efficiency.

[0022] Based on the motor voltage, the P motor speed operating points, the M motor output torque operating points, and the regulated switching frequency, the switching frequency operating table is constructed.

[0023] Optionally, the switching frequency operating condition table specifically includes: a switching frequency operating condition table corresponding to the minimum operating voltage, a switching frequency operating condition table corresponding to the rated operating voltage, and a switching frequency operating condition table corresponding to the maximum operating voltage.

[0024] Optionally, obtaining the reference frequency from a pre-built switching frequency operating condition table using the current operating parameters of the motor specifically includes:

[0025] Determine whether the current actual voltage is one of the following: the minimum operating voltage, the rated operating voltage, or the maximum operating voltage;

[0026] If so, based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage, determine the target switching frequency operating condition table; based on the current actual speed and / or the current actual torque, obtain the reference frequency from the target switching frequency operating condition table.

[0027] If not, based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage, two target switching frequency operating condition tables are determined according to the voltage approximation principle; with reference to the current actual voltage, the current actual speed, and the current actual torque, the reference frequency is calculated by interpolation from the two target switching frequency operating condition tables.

[0028] A second aspect of the present invention discloses a power system comprising a power battery, a motor controller, and a motor. The motor controller includes a changeover switch for converting the direct current (DC) power from the power battery into alternating current (AC) power to supply the motor. Specifically, the motor controller is used for:

[0029] Collect the current operating parameters of the motor;

[0030] The reference stator current is obtained from a pre-built motor current condition table using the current operating parameters of the motor, and the motor operation is controlled using the reference stator current; wherein, the motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under the three dimensions;

[0031] The reference frequency is obtained from a pre-constructed switching frequency operating condition table using the current operating parameters of the motor, and the switching on and off of the switching is controlled by the reference frequency; wherein, the switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves the preset system efficiency of the power system under the three dimensions.

[0032] A third aspect of the present invention discloses a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0033] A fourth aspect of the present invention discloses a new energy vehicle, including a memory, a processor, and a computer program stored in the memory and executable on a vehicle controller, wherein the vehicle controller executes the program to implement the steps of the method described in the first aspect.

[0034] Through one or more technical solutions of the present invention, the present invention has the following beneficial effects or advantages:

[0035] The technical solution in this invention constructs a motor current operating condition table and a switching frequency operating condition table to constrain the use of the motor and controller by taking into account both controller efficiency and motor efficiency, thereby achieving an overall efficiency improvement of the power system and filling the gap that the efficiency of the power system cannot be improved from the control level of the motor and controller.

[0036] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0037] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings.

[0038] In the attached diagram:

[0039] Figure 1 A flowchart of a control method for a power system according to an embodiment of the present invention is shown;

[0040] Figure 2 A schematic diagram illustrating the construction process of a motor current condition table according to an embodiment of the present invention is shown;

[0041] Figure 3 A schematic diagram of a power system according to an embodiment of the present invention is shown. Detailed Implementation

[0042] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0043] Firstly, this specification discloses a control method for a power system. This method is primarily used to improve the working efficiency of the power system. To facilitate explanation and clarification of the invention, the basic structure of the power system is first described below. Specifically, the power system includes a power battery, a motor controller, and a motor. The motor controller obtains power from the power battery and provides it to the motor so that the motor can drive the vehicle. The motor controller includes a changeover switch, for example, an insulated-gate bipolar transistor (IGBT) switch, but this does not constitute a limitation. The changeover switch is used to convert the direct current (DC) from the power battery into alternating current (AC) to supply the motor. The working efficiency of the power system is affected not only by the power battery but also by both the motor and the controller. On one hand, the output torque of the motor positively reflects its efficiency; the higher the output torque, the higher the motor efficiency. Furthermore, when achieving the same output torque, the lower the stator current, the higher the motor efficiency. Therefore, adjusting the motor stator current with the goal of "achieving the maximum motor output torque with the minimum stator current" will yield the maximum motor efficiency. On the other hand, adjusting the frequency of the changeover switch in the controller affects both the motor efficiency and the controller efficiency. Specifically, a higher switching frequency leads to greater losses in the motor controller and lower efficiency, but reduces current harmonic content, thus improving motor efficiency. Conversely, a lower switching frequency increases motor controller efficiency, but also lowers motor efficiency due to increased current harmonic content. Therefore, adjusting the switching frequency requires consideration of the overall system efficiency of the power system. By comprehensively considering both controller and motor losses, the switching frequency can be set to improve the overall efficiency of the power system. The solution in this application improves the efficiency of the power system from the control level of the motor and controller. By balancing controller and motor efficiency, the stator current and switching frequency are adjusted, and a motor current operating condition table and a switching frequency operating condition table are constructed to constrain the use of the motor and controller, thereby achieving an overall improvement in the efficiency of the power system.

[0044] like Figure 1 As shown, the power system control method provided in the embodiments of this specification includes at least the following steps:

[0045] S101 collects the current operating parameters of the motor.

[0046] Specifically, the motor's current operating parameters include: current actual voltage, current actual speed, and current actual torque. During the data collection process, these operating parameters are acquired through sensors installed at relevant locations on the motor, but this does not impose any limitations.

[0047] S102 obtains the reference stator current from the pre-built motor current condition table using the current operating parameters of the motor, and controls the motor operation using the reference stator current.

[0048] The motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque. It also contains the stator current required to achieve a preset motor efficiency across these three dimensions. The preset motor efficiency includes the maximum motor efficiency. During motor tuning, since motor output torque positively reflects motor efficiency, achieving the maximum motor output torque with the minimum stator current maximizes motor efficiency. Based on this principle, the stator current is continuously adjusted at each motor output torque condition point to achieve the goal of maximizing motor output torque with the minimum stator current, thus obtaining the minimum stator current corresponding to each motor output torque condition point. Therefore, the motor stator current in the motor current condition table specifically refers to the minimum stator current required to achieve the preset motor efficiency (e.g., maximum motor efficiency) across the three dimensions.

[0049] Further, see Figure 2 This is a schematic diagram illustrating the construction process of a motor current condition table, specifically including the following construction steps:

[0050] S201, under the limitation of motor voltage, determine P motor speed operating points and M motor output torque operating points.

[0051] The motor voltage is one of the following: minimum operating voltage, rated operating voltage, or maximum operating voltage. The selection range for the P motor speed operating points is (0, N). max ), N max This indicates the maximum operating speed. The motor speed operating points can be selected at intervals, for example, 500 rpm, but this is not a limitation. The selection range for the M motor output torque operating points is (0, T...). e-max ), T e-max This represents the maximum torque. The motor output torque operating point has a selection interval, for example, 10 Nm, but this is not a limitation. P ≥ 1, M ≥ 1, and both are positive integers.

[0052] When the motor voltage is any one of the minimum operating voltage, rated operating voltage, and maximum operating voltage, it can be obtained from (0, N) max Select P motor speed operating points within the range of (0, T) and from (0, T) e-max Select M motor output torque operating points within the range; the number of motor speed operating points and motor output torque operating points depends on the actual situation.

[0053] S202, when the motor speed reaches any motor speed operating point, the stator current of the motor is adjusted in combination with the first control target or the second control target to achieve M motor output torque operating points, and the minimum stator current corresponding to each of the M motor output torque operating points is obtained.

[0054] Each motor speed point requires adjustment of the motor stator current and motor output torque in conjunction with the first or second control target.

[0055] The first control objective is to adjust the motor output torque operating point using the minimum stator current. The second control objective is to adjust the motor output torque operating point using the minimum stator current under voltage limitations.

[0056] Specifically, when the motor speed reaches any operating point, it is determined whether the motor speed is below a set speed threshold. For example, the set speed threshold is 1000 rpm, but this does not constitute a restriction. If yes, it indicates that the motor speed is too low, and the first control target is used to adjust the motor stator current to achieve the motor output torque operating point; if no, it indicates that the motor speed is too high, and the second control target is used to adjust the motor stator current to achieve the motor output torque operating point.

[0057] When using the first control target to regulate the motor stator current and output torque, since the motor speed is relatively low and the voltage margin is ample, the stator current can be directly adjusted by referencing the maximum torque-to-current ratio to achieve the minimum stator current at the motor output torque operating point. It is worth noting that, with a fixed torque value at the motor output torque operating point, a lower stator current indicates higher motor efficiency. When using the second control target to regulate the motor stator current to achieve the motor output torque operating point, the motor faces voltage limitations due to the higher motor speed. Under voltage limitations, the stator current is adjusted by referencing the maximum torque-to-voltage ratio to achieve the minimum stator current at the motor output torque operating point under these voltage limitations.

[0058] S203 constructs a motor current condition table based on motor voltage, P motor speed operating points, M motor output torque operating points, and the minimum stator current regulated.

[0059] The minimum stator current includes the current module and the angle. It is worth noting that, with the current module value remaining constant, changing the angle will result in different torque outputs. Therefore, the current module and angle that achieve the motor's output torque operating point will be adjusted, which is the minimum stator current.

[0060] The above describes the specific construction process of the motor current condition tables. When the motor voltage is at its minimum operating voltage, rated operating voltage, and maximum operating voltage, corresponding motor current condition tables are constructed. Therefore, there are actually three motor current condition tables: one for the minimum operating voltage, one for the rated operating voltage, and one for the maximum operating voltage. For example, see Table 1, which shows the motor current condition table for the minimum operating voltage. In this table, the motor stator current is represented by the current magnitude Is and the angle ang, where the angle ang is equivalent to the phase. Other motor current condition tables are similar and will not be detailed further.

[0061] Table 1 (Minimum Operating Voltage U) low )

[0062]

[0063] The above is an introduction to the construction process of the motor current condition table. The following describes how to obtain the reference stator current from the motor current condition table.

[0064] In the process of obtaining the reference stator current from the pre-built motor current condition table using the current operating parameters of the motor, it is determined whether the current actual voltage is one of the following: minimum operating voltage, rated operating voltage, or maximum operating voltage.

[0065] If so, determine the target motor current condition table based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage; obtain the reference stator current from the target motor current condition table based on the current actual speed and / or the current actual torque.

[0066] For example, if the current actual voltage is the minimum operating voltage, then the motor current condition table corresponding to the minimum operating voltage is determined as the target motor current condition table. Then, based on the current actual speed and / or the current actual torque, the reference stator current can be found. If the current actual speed and the current actual torque are not in the target motor current condition table, then the corresponding reference stator current is calculated using an interpolation method (such as the proportional difference method).

[0067] If not, based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage, select two target motor current condition tables according to the voltage approximation principle; refer to the current actual voltage, the current actual speed, and the current actual torque, and interpolate from the two target motor current condition tables to calculate the reference stator current.

[0068] For example, the minimum operating voltage, rated operating voltage, and maximum operating voltage are 300V, 350V, and 400V, respectively. The current actual operating voltage is 380V, the actual speed is 2000rpm, and the actual output torque is 20Nm.

[0069] Based on the current actual operating voltage of 380V, and following the principle of voltage approximation, select the motor current condition tables corresponding to 350V and 400V respectively. Using the current actual speed of 2000rpm and / or the current actual torque of 20Nm, interpolate the corresponding motor stator current in each of the two current condition tables. Then, referring to the proportional relationship between the current actual operating voltage, rated operating voltage, and maximum operating voltage, use the interpolated stator currents from the two stator current condition tables to calculate the reference stator current again.

[0070] S103 obtains a reference frequency from a pre-built frequency table of the changeover switch using the current operating parameters of the motor, and uses the reference frequency to control the on / off state of the changeover switch.

[0071] The switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque. It also specifies the switching frequency at which the preset system efficiency of the power system is achieved under these three dimensions. Specifically, each switching frequency operating point in the table is the switching frequency at the set system efficiency obtained by adjusting the system efficiency using a power analyzer under these three dimensions.

[0072] Furthermore, the switching frequency operating condition table is constructed as follows:

[0073] Under the constraints of motor voltage, P motor speed operating points, and M motor output torque operating points, the switching frequency is adjusted to achieve a preset system efficiency. The preset system efficiency includes the maximum system efficiency.

[0074] The motor voltage is one of the following: minimum operating voltage, rated operating voltage, or maximum operating voltage. The selection range for the P motor speed operating points is (0, N). max ), N max This indicates the maximum operating speed. The motor speed operating points can be selected at intervals, for example, 500 rpm, but this is not a limitation. The selection range for the M motor output torque operating points is (0, T...). e-max ), T e-max This represents the maximum torque. The motor output torque operating point has a selection interval, for example, 10 Nm, but this is not a limitation. P ≥ 1, M ≥ 1, and both are positive integers.

[0075] When the motor voltage is any one of the minimum operating voltage, rated operating voltage, and maximum operating voltage, it can be obtained from (0, N) max Select P motor speed operating points within the range of (0, T) and from (0, T) e-max Select M motor output torque operating points within the range; the number of motor speed operating points and motor output torque operating points depends on the actual situation.

[0076] During adjustment, the control motor is positioned at three corresponding operating points across three dimensions. At each calibration point, the efficiency feedback from the dynamometer is compared to adjust the switching frequency. For example, the matching point between the switching frequency and the system's maximum efficiency is found. For instance, the switching frequency is first set to its maximum value, then the maximum system efficiency is found by lowering the frequency. The corresponding switching frequency is then adjusted using the maximum system efficiency as a reference.

[0077] Based on the motor voltage, P motor speed operating points, M motor output torque operating points, and the regulated switching frequency, a switching frequency operating condition table is constructed.

[0078] The above describes the specific construction process of the transfer switch frequency operating condition table. When the motor voltage is at its minimum operating voltage, rated operating voltage, and maximum operating voltage, a corresponding transfer switch frequency operating condition table is constructed. Therefore, there are actually three transfer switch frequency operating condition tables: one for the minimum operating voltage, one for the rated operating voltage, and one for the maximum operating voltage.

[0079] For example, see Table 2, which is a table of switching frequency operating conditions corresponding to the minimum operating voltage.

[0080] Table 2 (Minimum Operating Voltage U) low )

[0081]

[0082] The above is an introduction to the construction process of the transfer switch frequency condition table. The following describes how to obtain the reference frequency from the transfer switch frequency condition table.

[0083] When obtaining the reference frequency from the pre-built switching frequency condition table using the current operating parameters of the motor, determine whether the current actual voltage is one of the following: minimum operating voltage, rated operating voltage, or maximum operating voltage.

[0084] If so, determine the target switching frequency operating condition table based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage; obtain the reference frequency from the target switching frequency operating condition table based on the current actual speed and / or the current actual torque.

[0085] Specifically, if the current actual voltage is the minimum operating voltage, then the target switching frequency operating table is determined based on the switching frequency table corresponding to the minimum operating voltage. Then, the reference frequency is found based on the current actual speed and / or current actual torque. If the current actual speed and current actual torque are not in the target switching frequency operating table, the corresponding reference frequency is calculated using interpolation (e.g., proportional difference method).

[0086] If not, based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage, two target switching frequency operating condition tables are determined according to the voltage approximation principle; with reference to the current actual voltage, current actual speed, and current actual torque, the reference frequency is calculated by interpolation from the two target switching frequency operating condition tables.

[0087] For example, the minimum operating voltage, rated operating voltage, and maximum operating voltage are 300V, 350V, and 400V, respectively. The current actual operating voltage is 380V, the actual speed is 2000rpm, and the actual output torque is 20Nm.

[0088] Based on the current actual operating voltage of 380V, and following the principle of voltage approximation, select the corresponding switching frequency operating condition tables for 350V and 400V. Using the current actual speed of 2000rpm and / or the current actual torque of 20Nm, interpolate the corresponding switching frequencies in both the 350V and 400V tables to find the appropriate switching frequencies. Then, referring to the proportional relationship between the current actual operating voltage, rated operating voltage, and maximum operating voltage, use the switching frequencies found in the two tables to interpolate and calculate the reference frequency again.

[0089] The above is the technical solution of the present invention. Unlike conventional methods that only focus on the system efficiency caused by the power battery and do not consider the impact of motor stator current, switching frequency, etc. on the power system, the present invention can construct a motor current operating condition table and a switching frequency operating condition table to constrain the use of the motor and controller. Under different operating conditions, the corresponding switching frequency can be found, and the current magnitude and angle of the motor input can be realized to improve the system efficiency of the power system.

[0090] It is worth noting that since the efficiency of the motor controller and the efficiency of the motor are inversely related, after adjusting the motor stator current to achieve the maximum motor efficiency, it is necessary to focus on the overall system efficiency of the power system. By comprehensively considering the controller losses and motor losses, the switching frequency can be set so that the adjusted switching frequency can improve the overall efficiency of the power system.

[0091] Secondly, based on the same inventive concept as the control method for the power system provided in the first aspect of the embodiment, this specification also provides a power system, see [link to documentation]. Figure 3 This is a schematic diagram of a power system provided in an embodiment of this specification. The system includes: a power battery 301, a motor controller 302, and a motor 303. The motor controller 302 includes a changeover switch 304 for converting the direct current (DC) power from the power battery 301 into alternating current (AC) power to supply the motor 303. Specifically, the motor controller 302 is used for:

[0092] Collect the current operating parameters of the motor;

[0093] The reference stator current is obtained from a pre-built motor current condition table using the current operating parameters of the motor, and the motor operation is controlled using the reference stator current; wherein, the motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under the three dimensions;

[0094] The reference frequency is obtained from a pre-constructed switching frequency operating condition table using the current operating parameters of the motor, and the switching on and off of the switching is controlled by the reference frequency; wherein, the switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves the preset system efficiency of the power system under the three dimensions.

[0095] It should be noted that the specific way in which each module performs its operation in the power system provided in the embodiments of this specification has been described in detail in the method embodiments provided in the first aspect above. The specific implementation process can be referred to the method embodiments provided in the first aspect above, and will not be described in detail here.

[0096] Thirdly, based on the same inventive concept as the power system control method provided in the first aspect embodiment, this specification embodiment also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect embodiment.

[0097] Fourthly, based on the same inventive concept as the power system control method provided in the first aspect embodiment, this specification embodiment also provides a new energy vehicle, including a memory, a processor, and a computer program stored on the memory and executable on a vehicle controller, characterized in that the vehicle controller executes the program to implement the steps of the first aspect.

[0098] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0099] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A control method of a power system, characterized by, The power system includes a power battery, a motor controller, and a motor. The motor controller includes a transfer switch for converting the direct current (DC) from the power battery into alternating current (AC) to supply the motor. The method includes: Collect the current operating parameters of the motor; The reference stator current is obtained from a pre-constructed motor current condition table using the current operating parameters of the motor, and the motor operation is controlled using the reference stator current. The motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under these three dimensions. The motor current condition table is constructed as follows: under the constraint of motor voltage, P motor speed condition points and M motor output torque condition points are determined; wherein the motor voltage is one of the following: minimum operating voltage, rated operating voltage, and maximum operating voltage; when the motor... When the motor speed reaches any of the P motor speed operating points, the stator current is adjusted according to the first or second control objective to achieve M motor output torque operating points, thus obtaining the minimum stator current corresponding to each of the M motor output torque operating points. The first control objective is to use the minimum stator current to adjust the motor output torque operating point, and the second control objective is to use the minimum stator current to adjust the motor output torque operating point under voltage limitation. Based on the motor voltage, the P motor speed operating points, the M motor output torque operating points, and the adjusted minimum stator current, the motor current operating table is constructed. The reference frequency is obtained from a pre-constructed switching frequency operating condition table using the current operating parameters of the motor, and the switching on and off of the switching is controlled by the reference frequency; wherein, the switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves the preset system efficiency of the power system under the three dimensions.

2. The method of claim 1, wherein, The selection range for the P motor speed operating points is (0, ..., ...). N max ), N max Indicates the maximum operating speed; the selection range of the output torque operating points of the M motors is (0, ..., ... T e-max ), T e-max The maximum torque is indicated by P ≥ 1 and M ≥ 1, both of which are positive integers. The minimum stator current includes the current module and the angle.

3. The method of claim 2, wherein, The motor current condition tables are specifically: motor current condition tables corresponding to the minimum operating voltage, motor current condition tables corresponding to the rated operating voltage, and motor current condition tables corresponding to the maximum operating voltage.

4. The method of claim 3, wherein, The current operating parameters of the motor include: current actual voltage, current actual speed, and current actual torque; The step of obtaining the reference stator current from a pre-built motor current condition table using the current operating parameters of the motor specifically includes: Determine whether the current actual voltage is one of the following: the minimum operating voltage, the rated operating voltage, or the maximum operating voltage; If so, based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage, determine the target motor current condition table; based on the current actual speed and / or the current actual torque, obtain the reference stator current from the target motor current condition table; If not, based on the motor current condition table corresponding to the minimum operating voltage, the motor current condition table corresponding to the rated operating voltage, and the motor current condition table corresponding to the maximum operating voltage, two target motor current condition tables are selected according to the voltage approximation principle; with reference to the current actual voltage, the current actual speed, and the current actual torque, the reference stator current is calculated by interpolation from the two target motor current condition tables.

5. The method of claim 2, wherein, The switching frequency condition table is constructed in the following manner: Under the constraints of the motor voltage, the P motor speed operating points, and the M motor output torque operating points, the switching frequency is adjusted to achieve the preset system efficiency; the preset system efficiency includes the maximum system efficiency. Based on the motor voltage, the P motor speed operating points, the M motor output torque operating points, and the regulated switching frequency, the switching frequency operating table is constructed.

6. The method of claim 4, wherein, The switching frequency operating condition table specifically includes: the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage.

7. The method of claim 6, wherein, The step of obtaining the reference frequency from a pre-built switching frequency operating condition table using the current operating parameters of the motor specifically includes: Determine whether the current actual voltage is one of the following: the minimum operating voltage, the rated operating voltage, or the maximum operating voltage; If so, based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage, determine the target switching frequency operating condition table; based on the current actual speed and / or the current actual torque, obtain the reference frequency from the target switching frequency operating condition table. If not, based on the switching frequency operating condition table corresponding to the minimum operating voltage, the switching frequency operating condition table corresponding to the rated operating voltage, and the switching frequency operating condition table corresponding to the maximum operating voltage, two target switching frequency operating condition tables are determined according to the voltage approximation principle; with reference to the current actual voltage, the current actual speed, and the current actual torque, the reference frequency is calculated by interpolation from the two target switching frequency operating condition tables.

8. A power system characterized by, The power system includes a power battery, a motor controller, and a motor. The motor controller includes a transfer switch for converting the direct current (DC) power from the power battery into alternating current (AC) power to supply the motor. Specifically, the motor controller is used for: Collect the current operating parameters of the motor; The reference stator current is obtained from a pre-constructed motor current condition table using the current operating parameters of the motor, and the motor operation is controlled using the reference stator current. The motor current condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a motor stator current that achieves a preset motor efficiency under these three dimensions. The motor current condition table is constructed as follows: under the constraint of motor voltage, P motor speed condition points and M motor output torque condition points are determined; wherein the motor voltage is one of the following: minimum operating voltage, rated operating voltage, and maximum operating voltage; when the motor... When the motor speed reaches any of the P motor speed operating points, the stator current is adjusted according to the first or second control objective to achieve M motor output torque operating points, thus obtaining the minimum stator current corresponding to each of the M motor output torque operating points. The first control objective is to use the minimum stator current to adjust the motor output torque operating point, and the second control objective is to use the minimum stator current to adjust the motor output torque operating point under voltage limitation. Based on the motor voltage, the P motor speed operating points, the M motor output torque operating points, and the adjusted minimum stator current, the motor current operating table is constructed. The reference frequency is obtained from a pre-constructed switching frequency operating condition table using the current operating parameters of the motor, and the switching on and off of the switching is controlled by the reference frequency; wherein, the switching frequency operating condition table includes three dimensions: motor voltage, motor speed, and motor output torque, and has a switching frequency that achieves the preset system efficiency of the power system under the three dimensions.

9. A computer readable storage medium having stored thereon a computer program, characterized in that, When executed by a processor, the program implements the steps of the method according to any one of claims 1-7.

10. A new energy vehicle, comprising a memory, a processor, and a computer program stored in the memory and executable on a vehicle controller, characterized in that, When the vehicle controller executes the program, it implements the steps of the method according to any one of claims 1-7.

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