Assist motor control method, device, system, vehicle and readable storage medium

Abstract

This invention provides a method, apparatus, system, vehicle, and readable storage medium for controlling an auxiliary motor. The method includes: acquiring the rotor position angle and the dq-axis current in a two-phase rotating coordinate system; calculating the current angle in the two-phase rotating coordinate system based on the dq-axis current, and calculating the current vector angle in a two-phase stationary coordinate system based on the rotor position angle and the current angle; determining a first compensation amount and a second compensation amount based on the current vector angle, and compensating the α-axis reference voltage Uα in the two-phase stationary coordinate system with the first compensation amount and the β-axis reference voltage Uβ in the two-phase stationary coordinate system with the second compensation amount to compensate for the output voltage error occurring in the dead time of the three-phase inverter of the auxiliary motor, thereby suppressing torque ripple caused by the output voltage error in the three-phase inverter during the dead time; the values ​​of the first compensation amount and the second compensation amount correspond one-to-one with the current vector angle interval in which the current vector angle is located. This method can suppress torque ripple in the auxiliary motor.

Description

Technical Field

[0001] This invention relates to the field of control technology, and in particular to a power assist motor control method, device, system, vehicle, and readable storage medium. Background Technology

[0002] Electric power steering (EPS) systems improve the dynamic and static performance of a car during steering, ensuring handling stability and thus attracting increasing attention. Modern cars generally require steering systems to be safe, reliable, easy to operate, and energy efficient. Under any driving conditions, the steering wheel and wheels should not exhibit self-excited vibration or shaking to ensure a safe, quiet, and comfortable driving environment. Therefore, high demands are placed on the control of the power steering motor. However, existing power steering motors exhibit significant torque pulsation due to the dead-zone effect of three-phase inverters, causing pulsation in the steering wheel connected to the motor and reducing the dynamic and static performance of the car during steering. Summary of the Invention

[0003] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a power assist motor control method, device, system, vehicle, and readable storage medium. The control method compensates for the output voltage error of the three-phase inverter of the power assist motor during the dead time by compensating for the α-axis reference voltage Uα and β-axis reference voltage Uβ of the power assist motor in a stationary coordinate system. This suppresses the torque ripple caused by the output voltage error in the dead time of the three-phase inverter, thereby effectively suppressing the torque ripple of the power assist motor and improving the dynamic and static performance of the vehicle during steering.

[0004] To achieve the above objectives, in a first aspect, the present invention provides a power assist motor control method, comprising:

[0005] Obtain the rotor position angle and the dq-axis current in the two-phase rotating coordinate system;

[0006] The current angle in the two-phase rotating coordinate system is calculated based on the dq-axis current, and the current vector angle in the two-phase stationary coordinate system is calculated based on the rotor position angle and the current angle; and

[0007] The first compensation amount and the second compensation amount are determined based on the current vector angle. The first compensation amount is compensated for the α-axis reference voltage Uα in the two-phase stationary coordinate system, and the second compensation amount is compensated for the β-axis reference voltage Uβ in the two-phase stationary coordinate system, so as to compensate for the output voltage error of the three-phase inverter of the boost motor during the dead time, thereby suppressing the torque pulsation of the three-phase inverter caused by the output voltage error during the dead time.

[0008] The current vector angle changes sequentially within multiple current vector angle intervals, and the values ​​of the first compensation amount and the second compensation amount correspond one-to-one with the current vector angle interval in which the current vector angle is located.

[0009] In one embodiment, determining the first compensation amount and the second compensation amount based on the current vector angle includes:

[0010] The first compensation coefficient and the second compensation coefficient are determined based on the current vector angle, and the values ​​of the first compensation coefficient and the second compensation coefficient correspond one-to-one with the current vector angle interval in which the current vector angle is located.

[0011] The first compensation amount is calculated and determined based on the first compensation coefficient, and the second compensation amount is determined based on the second compensation coefficient.

[0012] In one embodiment, the first compensation amount is defined as U1, and the second compensation amount is defined as U2. The first compensation amount U1 and the second compensation amount U2 respectively satisfy the following relationship:

[0013] U1=K1*Td*Udc / Ts, U2=K2*Td*Udc / Ts;

[0014] Where Td is the dead time of the assist motor, Udc is the bus voltage of the assist motor, Ts is the carrier period of the assist motor, K1 and K2 are the first compensation coefficient and the second compensation coefficient, respectively. When the current vector angle is in any of the current vector angle intervals, there are preset first compensation coefficients and second compensation coefficients, and the first compensation coefficient and the second compensation coefficient are derived according to the current vector angle interval in which the current vector angle is currently located.

[0015] In one embodiment, the current vector angle is defined as θ, the current vector angle corresponding to the zero point of any phase current in the three-phase current is defined as the abrupt change angle θ', and the preset optimization angle is defined as δ;

[0016] Determining the first compensation amount and the second compensation amount based on the current vector angle includes:

[0017] When the current vector angle is in a current vector angle range outside the abrupt change range, a first compensation coefficient and a second compensation coefficient are determined based on the current vector angle, and the first compensation amount is further calculated and determined based on the first compensation coefficient, and the second compensation amount is determined based on the second compensation coefficient.

[0018] When the current vector angle is in the abrupt change range, a third compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle and the first linearization equation, and a fourth compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle and the second linearization equation. The first compensation amount is further calculated based on the third compensation coefficient, and the second compensation amount is determined based on the fourth compensation coefficient.

[0019] Wherein, the mutation interval is the vector angle interval corresponding to (θ'±δ), the values ​​of the first compensation coefficient and the second compensation coefficient correspond one-to-one with the current vector angle interval in which the current vector angle is located, the first linearization equation is the linearization equation corresponding to the current vector angle being in the vector angle interval of (θ'+δ), the second linearization equation is the linearization equation corresponding to the current vector angle being in the vector angle interval of (θ'-δ), and the first linearization equation is different from the second linearization equation.

[0020] In one embodiment, the first compensation amount is defined as U1, and the second compensation amount is defined as U2;

[0021] When the current vector angle is outside the abrupt change range, the first compensation amount U1 and the second compensation amount U2 satisfy the following relationships:

[0022] U1=K1*Td*Udc / Ts, U2=K2*Td*Udc / Ts

[0023] When the current vector angle is in the abrupt change range, the first compensation amount U1 and the second compensation amount U2 respectively satisfy the following relationship:

[0024]

[0025] Where Td is the dead time of the assist motor, Udc is the bus voltage of the assist motor, and Ts is the carrier period of the assist motor; K1 and K2 are the first compensation coefficient and the second compensation coefficient, respectively. When the current vector angle is in any of the current vector angle intervals, there are preset first compensation coefficients and second compensation coefficients, and the first compensation coefficient and the second compensation coefficient are derived according to the current vector angle interval in which the current vector angle is currently located.

[0026] In one embodiment, the preset optimization angle δ is less than or equal to 10 degrees.

[0027] In one embodiment, the current vector angle is equal to the sum of the rotor position angle and the current angle.

[0028] In one embodiment, obtaining the dq-axis current in a two-phase rotating coordinate system includes:

[0029] The three-phase current is sampled and converted into dq-axis current in a two-phase rotating coordinate system.

[0030] In a second aspect, the present invention provides a power assist motor control device, including a memory and a processor, wherein the memory stores a computer program that can be executed by the processor, and the processor executes the computer program to implement the power assist motor control method as described in any of the above embodiments.

[0031] Thirdly, the present invention provides a power assist motor control system, including a power assist motor and a power assist motor control device as described above.

[0032] Fourthly, the present invention provides a vehicle including the power assist motor control system described above.

[0033] Fifthly, the present invention provides a readable storage medium storing a computer program, which, when executed by a processor, implements the power assist motor control method as described in any of the above embodiments.

[0034] Compared with the prior art, the beneficial effects of the present invention are as follows: The power assist motor control method provided by the present invention compensates for the α-axis reference voltage Uα and β-axis reference voltage Uβ of the power assist motor in the stationary coordinate system, thereby compensating for the output voltage error of the three-phase inverter of the power assist motor during the dead time, and suppressing the torque pulsation of the three-phase inverter caused by the output voltage error during the dead time. This effectively suppresses the torque pulsation of the power assist motor, helps to reduce the pulsation of the steering wheel connected to the power assist motor, and improves the dynamic and static performance of the vehicle using the power assist motor during steering.

[0035] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0037] Figure 1 This is a flowchart of a power assist motor control method provided in one embodiment of the present invention.

[0038] Figure 2This is a structural block diagram of the power assist motor control system provided in one embodiment of the present invention.

[0039] Figure 3 This is the amplitude and direction pattern of the compensation voltage vector in one embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the compensation voltage-current angle curves corresponding to the α-axis reference voltage Uα and the β-axis reference voltage Uβ in one embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of the output current waveform of the assist motor in one embodiment of the present invention before compensation by the α-axis reference voltage Uα and the β-axis reference voltage Uβ.

[0042] Figure 6 This is a schematic diagram of the output current waveform of the assist motor in one embodiment of the present invention after compensation by the α-axis reference voltage Uα and the β-axis reference voltage Uβ.

[0043] Figure 7 This is a schematic diagram of the compensation voltage-current angle curves corresponding to the α-axis reference voltage Uα and the β-axis reference voltage Uβ in another embodiment of the present invention.

[0044] Explanation of key figure labels:

[0045] 100 - Assist motor control system; 10 - Assist motor; 20 - Assist motor control device;

[0046] 21-Current sampling and conversion module; 22-Rotor position angle sampling module; 23-Voltage compensation module. Detailed Implementation

[0047] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0048] Please refer to the following: Figure 1 and Figure 2 This invention provides a power assist motor control method applied to a power assist motor control system 100. The power assist motor control system 100 includes a power assist motor 10 and a power assist motor control device 20 connected to the power assist motor 10. The power assist motor control device 20 executes the power assist motor control method provided in this invention to control the power assist motor 10, thereby effectively suppressing torque pulsation in the power assist motor 10.

[0049] Specifically, such as Figure 1 As shown, in an embodiment of the present invention, the assist motor control method includes the following steps:

[0050] Step S1: Obtain the rotor position angle and the dq-axis current in the two-phase rotating coordinate system;

[0051] Step S2: Calculate the current angle in the two-phase rotating coordinate system based on the dq-axis current, and calculate the current vector angle in the two-phase stationary coordinate system based on the rotor position angle and the current angle; and

[0052] Step S3: Determine the first compensation amount and the second compensation amount according to the current vector angle, and compensate the first compensation amount for the α-axis reference voltage Uα in the two-phase stationary coordinate system, and compensate the second compensation amount for the β-axis reference voltage Uβ in the two-phase stationary coordinate system, so as to compensate for the output voltage error of the three-phase inverter of the boost motor during the dead time, thereby suppressing the torque pulsation of the three-phase inverter caused by the output voltage error during the dead time.

[0053] It should be noted that, in the embodiments of the present invention, the current vector angle changes sequentially within multiple current vector angle intervals, and the values ​​of the first compensation amount and the second compensation amount correspond one-to-one with the current vector angle interval in which the current vector angle is located. In other words, there is a one-to-one logical relationship between the first compensation amount, the second compensation amount, and the current vector angle interval in which the current vector angle is located. This logical relationship can be stored in the assist motor control device 20, so that when determining the current vector angle, the assist motor control device 20 can determine the corresponding first compensation amount and the second compensation amount according to the logical relationship, and compensate for the α-axis reference voltage Uα and the β-axis reference voltage Uβ in the two-phase stationary coordinate system, respectively. This will be described in more detail later. As those skilled in the art will understand, the output voltage error that occurs in the dead time of the three-phase inverter will vary depending on the polarity of the three-phase current. The output voltage error may be a positive error (i.e., the output voltage is greater than the required voltage) or a negative error (i.e., the output voltage is less than the required voltage). Accordingly, the first compensation amount and the second compensation amount can achieve negative compensation to offset the positive error, or they can achieve positive compensation to offset the negative error.

[0054] In summary, in the power assist motor control method provided in this embodiment of the invention, by compensating for the α-axis reference voltage Uα and β-axis reference voltage Uβ of the power assist motor 10 in the stationary coordinate system, the output voltage error of the three-phase inverter of the power assist motor 10 during the dead time is offset, thereby suppressing the torque pulsation of the three-phase inverter caused by the output voltage error during the dead time. This effectively suppresses the torque pulsation of the power assist motor 10, helps reduce the pulsation of the steering wheel connected to the power assist motor 10, and improves the dynamic and static performance of the vehicle using the power assist motor 10 during steering.

[0055] More specifically, such as Figure 2 As shown, in one embodiment of the present invention, the power assist motor control device 20 includes a current sampling and conversion module 21, a rotor position angle sampling module 22, and a voltage compensation module 23 respectively connected to the power assist motor 10. The current sampling and conversion module 21 and the rotor position angle sampling module 22 are also respectively connected to the voltage compensation module 23.

[0056] Among them, Figure 2 In the example, the current sampling and conversion module 21 is used to sample the three-phase current of the booster motor 10 and convert the three-phase current into a dq-axis current in a two-phase rotating coordinate system. That is, step S1, obtaining the dq-axis current in a two-phase rotating coordinate system, includes: sampling the three-phase current and converting the three-phase current into a dq-axis current in a two-phase rotating coordinate system. It should be noted that in Figure 2 In the example, the sampling of three-phase current can be achieved, but is not limited to, sampling through the lower bridge resistor, sampling through the output Hall sensor, or sampling through a single bus resistor. These sampling methods are all existing technologies. Furthermore, converting the sampled three-phase current into dq-axis current in a two-phase rotating coordinate system is also existing technology, and will not be elaborated upon further. It should also be noted that in... Figure 2 In the example, the current sampling and transformation module 21 is also used to perform arctangent calculation on the dq-axis current to obtain the current angle in the two-phase rotating coordinate system. In other embodiments, the current sampling and transformation module 21 can also send the dq-axis current obtained from the three-phase current conversion to the voltage compensation module 23, which performs arctangent calculation on the dq-axis current to obtain the current angle in the two-phase rotating coordinate system. It is easy to understand that performing arctangent calculation on the dq-axis current to obtain the current angle in the two-phase rotating coordinate system can be implemented using existing technology, which will not be elaborated further.

[0057] exist Figure 2In the example, the rotor position angle sampling module 22 is not limited to using at least one encoder among optical encoder, magnetic encoder, rotary encoder, and sine / cosine encoder to sample the rotor position angle of the booster motor 10. The principle of sampling the rotor position angle by any of the aforementioned encoders is existing technology and will not be elaborated here.

[0058] Please refer to it again. Figure 2 In one embodiment of the present invention, the current sampling and transformation module 21 can send the current angle calculated from the sampled three-phase current to the voltage compensation module 23, and the rotor position angle sampling module 22 can send the sampled rotor position angle to the voltage compensation module 23, so that the voltage compensation module 23 can calculate the current vector angle in the two-phase stationary coordinate system based on the rotor position angle and the current angle. Specifically, in Figure 2 In the example, the current vector angle in the two-phase stationary coordinate system can be obtained by adding the rotor position angle and the current angle. In other words, the current vector angle is equal to the sum of the rotor position angle and the current angle.

[0059] Furthermore, in Figure 2 In the example, after the voltage compensation module 23 calculates the current vector angle in the two-phase stationary coordinate system, it can determine the first compensation amount and the second compensation amount based on the current vector angle, and compensate the first compensation amount for the α-axis reference voltage Uα in the two-phase stationary coordinate system, and compensate the second compensation amount for the β-axis reference voltage Uβ in the two-phase stationary coordinate system, thereby compensating for the torque pulsation caused by the three-phase inverter of the boost motor during the dead time.

[0060] Optionally, in some embodiments of the present invention, step S3, which involves determining the first compensation amount and the second compensation amount based on the current vector angle, includes: step S31, determining the first compensation coefficient and the second compensation coefficient based on the current vector angle, wherein the values ​​of the first compensation coefficient and the second compensation coefficient correspond one-to-one with the current vector angle interval in which the current vector angle is located; step S32, calculating and determining the first compensation amount based on the first compensation coefficient, and determining the second compensation amount based on the second compensation coefficient.

[0061] For specific details, please refer to... Figure 3 , Figure 4 And as shown in Table 1 below, in one embodiment of the present invention, the voltage compensation module 23 or the assist motor control device 20 may be provided with a memory, the memory pre-stores a mapping table of current vector angle intervals and compensation coefficients as shown in Table 1, the mapping table includes the correspondence between current vector angle intervals, three-phase current directions, first compensation coefficient (K1) and second compensation coefficient (K2).

[0062] Table 1 Mapping Table of Current Vector Angle Range and Compensation Coefficient

[0063]

[0064] As shown in Table 1, each current vector angle within any given current vector angle interval corresponds to a preset first compensation coefficient and a second compensation coefficient, which are derived based on the current vector angle interval currently occupied by the current vector angle. Therefore, in this embodiment, after the voltage compensation module 23 calculates the current vector angle in the two-phase stationary coordinate system, it can determine the first compensation coefficient and the second compensation coefficient according to the mapping table pre-stored in the memory.

[0065] Furthermore, such as Figure 3 As shown, in this embodiment, the compensation amplitude for the current vector angle interval from U1comp to U6comp is Td*Udc / Ts, where Td is the dead time of the assist motor, Udc is the bus voltage of the assist motor, and Ts is the carrier period of the assist motor. Thus, the first compensation amount is defined as U1, and the second compensation amount is defined as U2. The first compensation amount U1 and the second compensation amount U2 satisfy the following relationships: U1 = K1*Td*Udc / Ts, U2 = K2*Td*Udc / Ts.

[0066] It is easy to understand that in this embodiment, after determining the first compensation coefficient and the second compensation coefficient based on the current vector angle and the mapping table, and further calculating the corresponding first compensation amount and the second compensation amount according to the corresponding formula, the α-axis reference voltage Uα and β-axis reference voltage Uβ in the two-phase stationary coordinate system can be directly compensated (see...). Figure 4 Compared to existing technologies that compensate for the three-phase voltage separately, the compensation scheme in this embodiment simplifies the compensation steps and facilitates development based on different assist motor models. Furthermore, please refer to... Figure 5 and Figure 6 Compared to the output current of the assist motor 10 before compensation with the α-axis reference voltage Uα and β-axis reference voltage Uβ, the current waveform curve is shown in the schematic diagram (see...). Figure 5 In an embodiment of the present invention, a schematic diagram of the current waveform curve of the output current of the assist motor 10 after compensation with the α-axis reference voltage Uα and the β-axis reference voltage Uβ is shown (see...). Figure 6 The output waveform distortion of the output current is significantly improved and effectively suppressed.

[0067] Alternatively, in other embodiments of the present invention, the current vector angle is defined as θ, the current vector angle corresponding to the zero point of any phase current in the three-phase current is defined as the abrupt change angle θ', the preset optimization angle is defined as δ, and step S3, which determines the first compensation amount and the second compensation amount based on the current vector angle, includes the following two steps:

[0068] When the current vector angle is outside the abrupt change interval, a first compensation coefficient and a second compensation coefficient are determined based on the current vector angle. The first compensation amount is then calculated based on the first compensation coefficient, and the second compensation amount is determined based on the second compensation coefficient. The abrupt change interval is the vector angle interval corresponding to (θ'±δ). The values ​​of the first and second compensation coefficients correspond one-to-one with the current vector angle interval in which the current vector angle is located. For details, please refer to the aforementioned mapping table 1. The calculation of the first compensation amount based on the first compensation coefficient and the second compensation amount based on the second compensation coefficient can be performed using the aforementioned two formulas (i.e., U1=K1*Td*Udc / Ts, U2=K2*Td*Udc / Ts). More detailed information can be found in the aforementioned related content, and will not be elaborated upon here.

[0069] When the current vector angle is within the abrupt change range, a third compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle, and the first linearization equation. A fourth compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle, and the second linearization equation. Furthermore, the first compensation amount is calculated based on the third compensation coefficient, and the second compensation amount is determined based on the fourth compensation coefficient. The first linearization equation is the linearization equation corresponding to the current vector angle being within the (θ'+δ) vector angle range, and the second linearization equation is the linearization equation corresponding to the current vector angle being within the (θ'-δ) vector angle range. The first linearization equation and the second linearization equation are different.

[0070] Considering that at the current zero-crossing point (i.e., the voltage abrupt change point), the sampling current angle will be inaccurate due to fluctuations and sampling errors, leading to inaccurate calculated current vector angle. If the compensation coefficient is still determined based on the current vector angle and the mapping table, the compensation amount determined based on the compensation coefficient will inevitably be incorrect. Therefore, in another embodiment of the present invention, when the current vector angle is in the abrupt change range, the third compensation coefficient and the fourth compensation coefficient are determined based on the current vector angle, the abrupt change angle, the preset optimization angle, and the corresponding first linearization equation and second linearization equation, respectively, thereby performing linearization processing on the current vector angle near the current zero-crossing point (i.e., the voltage abrupt change point) (see...). Figure 7 This can improve the accuracy of determining the compensation coefficient, thereby enabling the accurate determination of the first compensation amount and the second compensation amount. It avoids the risk of incorrect compensation amount calculation due to incorrect current angle judgment at voltage change points, and can avoid the introduction of additional harmonics due to incorrect compensation amount.

[0071] Specifically, in another embodiment of this invention, when the current vector angle is in the abrupt change range, the first compensation amount U1 and the second compensation amount U2 respectively satisfy the following relationship:

[0072]

[0073] The preset optimization angle δ is less than or equal to 10 degrees, and there is no limitation on this.

[0074] It is understood that in other embodiments of the present invention, when the current vector angle is in the abrupt change range, other compensation methods can also be used to optimize the current vector angle near the voltage abrupt change point. For example, but not limited to, compensation in the form of a tangent function. Specifically, before the current vector angle corresponding to each voltage abrupt change point arrives, the compensation amount is multiplied by a gain in the form of a tangent function so that the compensation amount decreases rapidly. After the current vector angle crosses the abrupt change point, the compensation amount is increased rapidly again. In this way, the compensated α-axis reference voltage Uα and β-axis reference voltage Uβ can be more accurate.

[0075] It should be noted that, in the embodiments of the present invention, the voltage compensation module 23 compensates the α-axis reference voltage Uα and β-axis reference voltage Uβ of the assist motor 10 in the two-phase stationary coordinate system. This can be achieved through an SVPWM module, and the specific implementation principle is existing technology, which will not be elaborated here. Furthermore, similar to existing assist motor control devices, the assist motor control device 20 may also include other module components, such as, but not limited to, a motor speed calculation module, a current calculation module, a current PI module, a temperature detection module, etc., which will also not be elaborated here.

[0076] Furthermore, embodiments of the present invention provide a power assist motor control device, including a memory and a processor connected to the memory. The memory stores a computer program that can be executed by the processor. When the processor executes the computer program, it can implement the power assist motor control method as described in any of the above embodiments. For details, please refer to the relevant descriptions in the foregoing method embodiments.

[0077] Furthermore, an embodiment of the present invention provides a vehicle, the vehicle including the power assist motor control system 100 of the above embodiment, the power assist motor control system 100 including a power assist motor 10 and a power assist motor control device 20 connected to the power assist motor 10, the power assist motor control device 20 being used to execute the power assist motor control method provided in the embodiment of the present invention to control the power assist motor 10, thereby effectively suppressing the torque pulsation of the power assist motor 10.

[0078] The vehicle mentioned can be any type of vehicle, such as a fuel-powered vehicle or an electric vehicle, and there is no limitation on this.

[0079] Furthermore, embodiments of the present invention provide a readable storage medium storing a computer program thereon, which, when executed by a processor, implements the power assist motor control method as described in any of the foregoing embodiments, as detailed in the relevant descriptions in the foregoing method embodiments.

[0080] In the description of this invention, the terms "embodiment," "specific embodiment," "example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0081] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A method for controlling an assist motor, characterized in that, include: Obtain the rotor position angle and the dq-axis current in the two-phase rotating coordinate system; The current angle in the two-phase rotating coordinate system is calculated based on the dq axis current, and the current vector angle in the two-phase stationary coordinate system is calculated based on the rotor position angle and the current angle. as well as The first compensation amount and the second compensation amount are determined based on the current vector angle. The first compensation amount is compensated for the α-axis reference voltage Uα in the two-phase stationary coordinate system, and the second compensation amount is compensated for the β-axis reference voltage Uβ in the two-phase stationary coordinate system, so as to compensate for the output voltage error of the three-phase inverter of the boost motor during the dead time, thereby suppressing the torque pulsation of the three-phase inverter caused by the output voltage error during the dead time. The current vector angle changes sequentially within multiple current vector angle intervals, and the values ​​of the first compensation amount and the second compensation amount correspond one-to-one with the current vector angle interval in which the current vector angle is located. The current vector angle is defined as θ, the current vector angle corresponding to the zero point of any phase current in the three-phase current is defined as the abrupt change angle θ', and the preset optimization angle is defined as δ; Determining the first compensation amount and the second compensation amount based on the current vector angle includes: When the current vector angle is in a current vector angle range outside the abrupt change range, a first compensation coefficient and a second compensation coefficient are determined based on the current vector angle, and the first compensation amount is further calculated and determined based on the first compensation coefficient, and the second compensation amount is determined based on the second compensation coefficient. When the current vector angle is in the abrupt change range, a third compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle and the first linearization equation, and a fourth compensation coefficient is determined based on the current vector angle, the abrupt change angle, the preset optimized angle and the second linearization equation. The first compensation amount is further calculated based on the third compensation coefficient, and the second compensation amount is determined based on the fourth compensation coefficient. Wherein, the mutation interval is the vector angle interval corresponding to (θ'±δ), the values ​​of the first compensation coefficient and the second compensation coefficient correspond one-to-one with the current vector angle interval in which the current vector angle is located, the first linearization equation is the linearization equation corresponding to the current vector angle being in the vector angle interval of (θ'+δ), the second linearization equation is the linearization equation corresponding to the current vector angle being in the vector angle interval of (θ'-δ), and the first linearization equation is different from the second linearization equation.

2. The power assist motor control method as described in claim 1, characterized in that, The first compensation amount is defined as U1, and the second compensation amount is defined as U2; When the current vector angle is outside the abrupt change range, the first compensation amount U1 and the second compensation amount U2 satisfy the following relationships: When the current vector angle is in the abrupt change range, the first compensation amount U1 and the second compensation amount U2 respectively satisfy the following relationship: ， ； Where Td is the dead time of the assist motor, Udc is the bus voltage of the assist motor, and Ts is the carrier period of the assist motor; K1 and K2 are the first compensation coefficient and the second compensation coefficient, respectively. When the current vector angle is in any of the current vector angle intervals, there are preset first compensation coefficients and second compensation coefficients, and the first compensation coefficient and the second compensation coefficient are derived according to the current vector angle interval in which the current vector angle is currently located.

3. The power assist motor control method as described in claim 2, characterized in that, The preset optimization angle δ is less than or equal to 10 degrees.

4. The power assist motor control method according to any one of claims 1 to 3, characterized in that, The current vector angle is equal to the sum of the rotor position angle and the current angle.

5. The power assist motor control method according to any one of claims 1 to 3, characterized in that, Obtaining the dq-axis current in a two-phase rotating coordinate system includes: The three-phase current is sampled and converted into dq-axis current in a two-phase rotating coordinate system.

6. A power assist motor control device, comprising a memory and a processor, wherein the memory stores a computer program executable by the processor, characterized in that, When the processor executes the computer program, it implements the power assist motor control method as described in any one of claims 1 to 5.

7. A power assist motor control system, characterized in that, It includes a power assist motor and a power assist motor control device as described in claim 6.

8. A vehicle, characterized in that, Includes the power assist motor control system as described in claim 7.

9. A readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the power assist motor control method as described in any one of claims 1 to 5.

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