Motor power automatic tracking method and system

Abstract

The invention provides a motor power automatic tracking method and system, and the method comprises the steps: collecting the three-phase current of a motor through a current sensor, carrying out the Clarke conversion of the three-phase current, and obtaining the current of an alpha-beta coordinate system. And performing Park transformation on the current of the alpha-beta coordinate system to obtain the current of the dq coordinate system. And comparing the dq coordinate system current with the feedback current, and generating a PWM waveform according to a comparison result. And performing phase angle conversion on the phase angle to obtain a converted phase angle. And integrating the converted phase angle, the PWM waveform and the motor torque to obtain a compensation current curve, and adjusting the motor power according to the compensation current curve. And through coordinate transformation, original complex multivariable variables are converted into a specific coordinate system, so that accurate speed control and torque control can be implemented conveniently. The motor power is adjusted according to the compensation current curve, the motor current can be compensated constantly under the condition of constant voltage, the motor power can be accurately controlled, and energy is saved on the premise that the requirement of an application scene for the motor driving performance is met.

Description

Technical Field

[0001] The present invention relates to the technical field of motor power regulation, and in particular to a motor power automatic tracking method and system. Background Art

[0002] Motors are power devices that convert electrical energy into mechanical energy. They are widely used in various engineering control fields. The speed of the motor needs to be adjusted to adjust the power consumption and energy conversion efficiency of the motor. Field Oriented Control (FOC) is an advanced motor control technology that achieves precise control of the motor by separating the torque and flux components of the motor.

[0003] Most existing motor control technologies use MTPA (Maximum Torque Per Ampere) to control permanent magnet motors. The purpose of MTPA control is to obtain the maximum motor torque output with the minimum stator current under given motor load conditions. However, the accuracy of MTPA technology in controlling motor power is not high enough, and the operating efficiency of the motor needs to be further improved.

[0004] In summary, a method is needed to control the motor power with high accuracy and enable the motor to have high operating efficiency. Summary of the invention

[0005] In order to overcome the problems existing in the related art, one of the purposes of the present invention is to provide a method for automatically tracking motor power, which controls the motor power with high accuracy and can make the motor have higher operating efficiency.

[0006] A method for automatically tracking motor power, comprising:

[0007] The three-phase current of the motor is collected by the current sensor, and the three-phase current includes the A-phase current i a 、B phase current i b and C phase current i c ;

[0008] Performing Clarke transformation on the three-phase current to obtain αβ coordinate system current;

[0009] Performing Park transformation on the αβ coordinate system current to obtain the dq coordinate system current;

[0010] Comparing the dq coordinate system current with the feedback current, and generating a PWM waveform according to the comparison result;

[0011] Performing phase angle transformation on the phase angle to obtain a transformed phase angle;

[0012] Integrating the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve;

[0013] The motor power is adjusted according to the compensation current curve.

[0014] In a preferred technical solution of the present invention, before performing phase angle transformation on the phase angle to obtain the transformed phase angle, the method further includes:

[0015] Express the phase angle in complex form;

[0016] Setting the real part of the phase angle as the starting phase angle;

[0017] The imaginary part of the phase angle is set to the adjusted phase angle.

[0018] In a preferred technical solution of the present invention, the integration of the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve includes:

[0019] Constructing a first integral function;

[0020] The transformed phase angle, PWM waveform and motor torque are used as integral variables, and the first integral function is triple integrated to obtain a compensation current curve.

[0021] In a preferred technical solution of the present invention, adjusting the motor power according to the compensation current curve includes:

[0022] Get the reference current of the motor;

[0023] Calculating a current difference between the compensation current curve and the reference current;

[0024] The portion of the compensation current curve where the current difference is less than 0 is set as a preset current to obtain a final current curve;

[0025] The motor power is adjusted according to the final current curve.

[0026] In a preferred technical solution of the present invention, performing Clarke transformation on the three-phase current to obtain the αβ coordinate system current includes:

[0027] The αβ coordinate system current is calculated according to the following formula:

[0028]

[0029] Among them, i α is the α phase current in the αβ coordinate system, i β is the β-phase current in the αβ coordinate system, and the αβ coordinate system is a two-phase stationary coordinate system.

[0030] In a preferred technical solution of the present invention, the Park transformation is performed on the αβ coordinate system current to obtain the dq coordinate system current, including:

[0031] The αβ coordinate system current is transformed into the dq coordinate system according to the following formula to obtain the dq coordinate system current:

[0032] i d =i α cosθ+i β cosθ;

[0033] i q =-i α sinθ+i β cosθ;

[0034] Among them, i d is the d-axis current, i q is the q-axis current, and θ is the motor rotation angle.

[0035] In a preferred technical solution of the present invention, the step of comparing the dq coordinate system current and the feedback current and generating a PWM waveform according to the comparison result includes:

[0036] Calculating the current difference between the dq coordinate system current and the feedback current;

[0037] Performing proportional integral torque current adjustment operation and proportional integral excitation current adjustment operation on the current difference to obtain a d-axis voltage and a q-axis voltage;

[0038] The d-axis voltage and the q-axis voltage are subjected to Park inverse transformation and Clark inverse transformation in sequence to obtain a three-phase PWM voltage.

[0039] The second object of the present invention is to provide a motor power automatic tracking system, which is applied to any of the motor power automatic tracking methods described above, and the system includes a current sensor, which collects the three-phase current of the motor and provides the three-phase current to a coordinate system transformation module; the output end of the coordinate system transformation module is connected to the input end of the phase angle transformation module, the output end of the phase angle transformation module is connected to the input end of the integration module, and the output end of the integration module is connected to the compensation end.

[0040] In a preferred technical solution of the present invention, the coordinate system transformation module includes a Clark transformer and a Park transformer, the output end of the current sensor is connected to the input end of the Clark transformer, and the output end of the Clark transformer is connected to the input end of the Park transformer.

[0041] In a preferred technical solution of the present invention, the motor power automatic tracking system also includes a coordinate system inverse transformation module, which includes a Clark inverse transformer, a Park inverse transformer, a torque current regulator, an excitation current regulator and a current difference calculator, the current difference calculator is connected to the input end of the torque current regulator and the input end of the excitation current regulator, the output end of the torque current regulator and the output end of the excitation current regulator are connected to the input end of the Park inverse transformer, and the output end of the Park inverse transformer is connected to the integration module through the Clark inverse transformer.

[0042] The beneficial effects of the present invention are:

[0043] The motor power automatic tracking method provided by the present invention comprises collecting the three-phase current of the motor through a current sensor, wherein the three-phase current comprises an A-phase current ia, a B-phase current ib and a C-phase current ic. The three-phase current is subjected to Clarke transformation to obtain an αβ coordinate system current. Clarke transformation can convert the three-phase current of the motor from a three-phase stationary coordinate system to a two-phase stationary coordinate system, thereby eliminating the zero-sequence component, so that the motor control system can process two components that are independent of the rotor position, and simplify the structure of the motor control system. Park transformation is performed on the αβ coordinate system current to obtain a dq coordinate system current. On the basis of Clarke transformation, the two-phase stationary coordinate system, i.e., the αβ coordinate system, is further transformed into a dq coordinate system that rotates synchronously with the rotor magnetic field. In the dq coordinate system, the d-axis is aligned with the permanent magnet magnetic field, and the q-axis is perpendicular to the permanent magnet magnetic field. The above transformation makes the motor model appear in a form similar to a DC motor in the dq coordinate system, so that a vector control strategy similar to that of a DC motor can be adopted to achieve effective decoupling control of various motor physical quantities such as voltage, current and flux. Through coordinate transformation, the originally complex multi-variable is converted to a specific coordinate system, so that an independent control channel can be used to control the motor, which is convenient for implementing precise speed control and torque control, and can improve the dynamic performance and stability of the system. The dq coordinate system current and the feedback current are compared, and a PWM waveform is generated according to the comparison result. The phase angle is transformed to obtain the transformed phase angle. The transformed phase angle, PWM waveform and motor torque are integrated to obtain the compensation current curve. The motor power is adjusted according to the compensation current curve. The motor current can be compensated at all times under constant voltage conditions. The compensation current curve is based on the transformed phase angle, PWM waveform and motor torque, which can accurately control the motor power, so that the motor has a higher operating efficiency and saves energy while meeting the requirements of the application scenario for motor drive performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a flow chart of the motor power automatic tracking method;

[0045] Figure 2 It is a schematic block diagram of the structure of the motor power automatic tracking system;

[0046] Figure 3 It is a schematic diagram of the structure of the coordinate system transformation module;

[0047] Figure 4 It is a structural schematic diagram of the coordinate system inverse transformation module.

[0048] Figure numerals: 1. Motor; 2. Current sensor; 3. Coordinate system transformation module; 31. Clark transformer; 32. Park transformer; 4. Phase angle transformation module; 5. Integration module; 6. Compensation end; 7. Coordinate system inverse transformation module; 71. Clark inverse transformer; 72. Park inverse transformer; 73. Torque current regulator; 74. Excitation current regulator; 75. Current difference calculator. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0050] Example 1

[0051] like Figure 1 As shown, this embodiment provides a method for automatically tracking motor power, including:

[0052] S1: The three-phase current of the motor is collected by the current sensor, and the three-phase current includes the A-phase current i a 、B phase current i b and C phase current i c .

[0053] S2: Perform Clarke transformation on the three-phase current to obtain the αβ coordinate system current.

[0054] S3: Performing Park transformation on the αβ coordinate system current to obtain the dq coordinate system current.

[0055] S4: Compare the dq coordinate system current and the feedback current, and generate a PWM waveform according to the comparison result.

[0056] S5: Perform phase angle transformation on the phase angle to obtain a transformed phase angle.

[0057] S6: Integrate the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve.

[0058] S7: Adjusting the motor power according to the compensation current curve.

[0059] The step of integrating the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve comprises:

[0060] S61: Construct a first integral function.

[0061] S62: Using the transformed phase angle, PWM waveform and motor torque as integral variables, perform triple integration on the first integral function to obtain a compensation current curve.

[0062] The first integral function is a function with the transformed phase angle, PWM waveform and motor torque as independent variables. Using the first integral function can better reflect the coupling relationship between the transformed phase angle, PWM waveform and motor torque, thereby calculating the compensation current value based on the transformed phase angle, PWM waveform and motor torque, and plotting multiple compensation current values ​​into a compensation current curve.

[0063] The calculation formula of the first integral function is as follows:

[0064] I r =∫∫∫y1(θ)u(t)T(n)dθdtdn;

[0065] Among them, I r is the compensated current, θ is the transformed phase angle, t is the time, n is the motor speed, y1(θ) is the phase angle function of the motor, u(t) is the voltage function of the motor, and T(n) is the torque function of the motor.

[0066] With time as the X-axis, the compensated current I r The Y-axis is used to draw the compensation current curve.

[0067] Adjusting the motor power according to the compensation current curve includes:

[0068] S71: Obtain the reference current of the motor.

[0069] S72: Calculate the current difference between the compensation current curve and the reference current.

[0070] S73: setting the portion of the compensation current curve where the current difference is less than 0 as a preset current to obtain a final current curve.

[0071] S74: Adjusting the motor power according to the final current curve.

[0072] The reference current of the motor is a horizontal straight line, and the compensation current curve is a periodic curve. In one cycle, the current in a part of the compensation current curve is less than the reference current, that is, the current difference in the area is less than 0.

[0073] The part of the compensation current curve where the current difference is less than 0 is set as the preset current. In this embodiment, the preset current is 0 as an example to obtain the final current curve, and the final current curve is a periodic sawtooth curve. The horizontal coordinates of the final compensation current curve and the compensation current curve are both time, and the vertical coordinates are both motor current. The use of the final current curve can accurately adjust the motor power so that the motor has a higher operating efficiency and saves energy while meeting the requirements of the application scenario for the motor drive performance. As an example, from the 0th second to the 4th second, the motor current rises from 0A to 2A; from the 4th second to the 8th second, the motor current drops from 2A to 0A; from the 8th second to the 12th second, the motor current is 0A.

[0074] The motor power automatic tracking method provided in this embodiment includes collecting the three-phase current of the motor through a current sensor, and the three-phase current includes the A-phase current ia, the B-phase current ib and the C-phase current ic. The three-phase current is subjected to Clarke transformation to obtain the αβ coordinate system current. Clarke transformation can convert the three-phase current of the motor from the three-phase stationary coordinate system to the two-phase stationary coordinate system, thereby eliminating the zero-sequence component, so that the motor control system can process two components that are independent of the rotor position, and simplify the structure of the motor control system. Park transformation is performed on the αβ coordinate system current to obtain the dq coordinate system current. On the basis of Clarke transformation, the two-phase stationary coordinate system, i.e., the αβ coordinate system, is further transformed into a dq coordinate system that rotates synchronously with the rotor magnetic field. In the dq coordinate system, the d-axis is aligned with the permanent magnet magnetic field, and the q-axis is perpendicular to the permanent magnet magnetic field. The above transformation makes the motor model appear in a form similar to that of a DC motor in the dq coordinate system, so that a vector control strategy similar to that of a DC motor can be adopted to achieve effective decoupling control of various physical quantities of the motor, such as voltage, current and flux. Through coordinate transformation, the originally complex multi-variable is converted to a specific coordinate system, so that an independent control channel can be used to control the motor, which is convenient for implementing precise speed control and torque control, and can improve the dynamic performance and stability of the system. The dq coordinate system current and the feedback current are compared, and a PWM waveform is generated according to the comparison result. The phase angle is transformed to obtain the transformed phase angle. The transformed phase angle, PWM waveform and motor torque are integrated to obtain the compensation current curve. The motor power is adjusted according to the compensation current curve. The motor current can be compensated at all times under constant voltage conditions. The compensation current curve is based on the transformed phase angle, PWM waveform and motor torque, which can accurately control the motor power, so that the motor has a higher operating efficiency and saves energy while meeting the requirements of the application scenario for motor drive performance.

[0075] Example 2

[0076] This embodiment provides a method for automatically tracking motor power, and this embodiment only describes the differences from Embodiment 1. The Clarke transformation of the three-phase current to obtain the αβ coordinate system current includes:

[0077] The αβ coordinate system current is calculated according to the following formula:

[0078]

[0079] Among them, i α is the α phase current in the αβ coordinate system, i β is the β-phase current in the αβ coordinate system, and the αβ coordinate system is a two-phase stationary coordinate system.

[0080] when When it is an equal amplitude transformation, that is, the value of each phase variable in the three-phase coordinate system is equal to the amplitude in the αβ coordinate system, and the formula of Clarke transformation becomes:

[0081]

[0082] when When it is equal power transformation, that is, the power and torque of the motor are equal in the three-phase coordinate system and the αβ coordinate system, the formula of Clarke transformation becomes:

[0083]

[0084] The calculation formula of parameter P is as follows:

[0085]

[0086] Among them, N2 is the number of turns of each phase of the three-phase winding, and N1 is the number of turns of each phase of the two-phase winding.

[0087] Vector coordinate transformation is to use magnetic potential or current space vector to describe equivalent three-phase magnetic field, two-phase magnetic field and rotating DC magnetic field, and transform their coordinates. Therefore, vector coordinate transformation must follow the following two principles: (1) The rotating magnetic field generated by the current before and after the transformation is equivalent. (2) The motor power of the two systems does not change before and after the transformation.

[0088] According to the vector transformation principle, the magnetic field before and after Clarke transformation is equivalent, that is, the projections of the synthesized magnetic potential vector on the coordinate axes of the two coordinate systems are equal. Assuming that the magnetomotive force is sinusoidally distributed, when the three-phase total magnetomotive force is equal to the two-phase total magnetomotive force, the projections of the instantaneous magnetomotive force of the two sets of windings on the two-phase coordinate system are equal.

[0089] The performing Park transformation on the αβ coordinate system current to obtain the dq coordinate system current includes:

[0090] The αβ coordinate system current is transformed into the dq coordinate system according to the following formula to obtain the dq coordinate system current:

[0091] i d =i α cosθ+i β cosθ;

[0092] i q =-i α sinθ+i β cosθ;

[0093] Among them, i d is the d-axis current, i q is the q-axis current, and θ is the motor rotation angle.

[0094] Park transform is a method of converting a two-phase signal into a rotating coordinate system signal. It converts the α-axis and β-axis signals into d-axis and q-axis signals, where the d-axis signal is synchronized with the rotating magnetic field and the q-axis signal is perpendicular to the magnetic field. Park transform is often used to control AC motors or analyze AC circuits.

[0095] When Park transform is used to establish the differential equation of the electromagnetic relationship of the rotor loop, its coefficient matrix becomes a constant matrix instead of a coefficient matrix that changes with time and space, thereby simplifying the differential equation for analyzing the electromagnetic relationship of the motor.

[0096] In the case of uniform circular rotation, the Park transformation transforms the rotating vector into a quantity in a stationary rectangular coordinate system through a certain angle rotation transformation, that is, replacing the rotating coordinate system with the spatial stationary coordinate system.

[0097] In this embodiment, the three-phase current is subjected to Clarke transformation to obtain the αβ coordinate system current. The αβ coordinate system current is subjected to Park transformation to obtain the dq coordinate system current. The magnetic fields before and after the Clarke transformation are equivalent, that is, the projections of the synthesized magnetic potential vector on the coordinate axes of the two coordinate systems are equal. When the Park transformation establishes the differential equation of the electromagnetic relationship of the rotor loop, its coefficient matrix becomes a constant matrix instead of a coefficient matrix that changes with time and space, thereby simplifying the differential equation for analyzing the electromagnetic relationship of the motor.

[0098] Example 3

[0099] This embodiment provides a method for automatically tracking motor power, and this embodiment only describes the differences from Embodiment 1. The dq coordinate system current and the feedback current are compared, and a PWM waveform is generated according to the comparison result, including:

[0100] S41: Calculate the current difference between the dq coordinate system current and the feedback current.

[0101] S42: performing proportional integral torque current adjustment operation and proportional integral excitation current adjustment operation on the current difference to obtain a d-axis voltage and a q-axis voltage.

[0102] S43: performing Park inverse transformation and Clark inverse transformation on the d-axis voltage and the q-axis voltage in sequence to obtain a three-phase PWM voltage.

[0103] The proportional link can improve the control accuracy of torque current and excitation current and reduce system deviation, and the integral link can eliminate the steady-state error of torque current and excitation current.

[0104] Park's inverse transform is the process of transforming physical quantities in a rotating coordinate system back to a stationary coordinate system. It is mainly used to transform physical quantities such as current and voltage in a rotating coordinate system back to a stationary coordinate system for analysis and control.

[0105] Clarke inverse transformation is the process of converting the electrical quantity of the two-phase stationary coordinate system back to the three-phase stationary coordinate system. The two-phase stationary coordinate system is the αβ coordinate system, and the three-phase stationary coordinate system is the ABC coordinate system. This process is the inverse operation of Clarke transformation and is used to restore the electrical quantity in the two-phase system to the three-phase system.

[0106] The three-phase PWM voltage is provided to the motor, and the u-phase wiring inputs the U-phase PWM voltage V to the motor u , the V-phase wiring inputs the V-phase PWM voltage V to the motor v , the w-phase wiring inputs the W-phase PWM voltage V to the motor w .

[0107] Before performing phase angle transformation on the phase angle to obtain the transformed phase angle, the method further comprises:

[0108] S41': The phase angle is expressed in complex form.

[0109] S42': Set the real part of the phase angle as the starting phase angle.

[0110] S43': setting the imaginary part of the phase angle as the adjusted phase angle.

[0111] Multiply the adjusted phase angle by the imaginary unit to get the imaginary part of the phase angle. Add the real part of the phase angle to the imaginary part of the phase angle to get the complex form of the phase angle.

[0112] The phase angle is expressed in complex form, which can simultaneously express the initial value and adjustment value of the phase angle.

[0113] This embodiment compares the dq coordinate system current and the feedback current, and generates a PWM waveform according to the comparison result, including calculating the current difference between the dq coordinate system current and the feedback current, performing proportional integral torque current regulation operation and proportional integral excitation current regulation operation on the current difference, and obtaining the d-axis voltage and the q-axis voltage. The d-axis voltage and the q-axis voltage are subjected to Park inverse transformation and Clark inverse transformation in sequence to obtain a three-phase PWM voltage. Park inverse transformation is the process of transforming the physical quantity in the rotating coordinate system back to the stationary coordinate system, and Clark inverse transformation is the process of transforming the electrical quantity in the two-phase stationary coordinate system back to the three-phase stationary coordinate system.

[0114] Example 4

[0115] like Figure 2-Figure 4 As shown, this embodiment provides a motor power automatic tracking system, which is applied to the motor power automatic tracking method of any one of Embodiments 1 to 3. The system includes a current sensor 2, which collects the three-phase current of the motor 1 and provides the three-phase current to a coordinate system transformation module 3; the output end of the coordinate system transformation module 3 is connected to the input end of the phase angle transformation module 4, the output end of the phase angle transformation module 4 is connected to the input end of the integration module 5, and the output end of the integration module 5 is connected to the compensation end 6.

[0116] A coordinate system inverse transformation module 7 is also provided between the coordinate system transformation module 3 and the phase angle transformation module 4 .

[0117] The current sensor 2 is divided into a shunt, an electromagnetic current transformer and an electronic current transformer. The electronic current transformer includes a Hall current sensor and a variable frequency power sensor. Compared with the electromagnetic current sensor, the electronic current transformer has no ferromagnetic saturation, a wide transmission bandwidth, a small secondary load capacity, a small size, and a light weight. It is the future development direction of the current sensor 2. This embodiment takes the current sensor 2 as an electronic current transformer as an example.

[0118] The coordinate system transformation module 3 includes a Clark transformer 31 and a Park transformer 32 . The output end of the current sensor 2 is connected to the input end of the Clark transformer 31 , and the output end of the Clark transformer 31 is connected to the input end of the Park transformer 32 .

[0119] The Clark transformer 31 performs Clark transformation on the three-phase current provided by the current sensor 2 to obtain the αβ coordinate system current. The Park transformer 32 performs Park transformation on the αβ coordinate system current output by the Clark transformer 31 to obtain the dq coordinate system current.

[0120] The motor power automatic tracking system also includes a coordinate system inverse transformation module 7, which includes a Clark inverse transformer 71, a Park inverse transformer 72, a torque current regulator 73, an excitation current regulator 74 and a current difference calculator 75. The current difference calculator 75 is connected to the input end of the torque current regulator 73 and the input end of the excitation current regulator 74, the output end of the torque current regulator 73 and the output end of the excitation current regulator 74 are connected to the input end of the Park inverse transformer 72, and the output end of the Park inverse transformer 72 is connected to the integration module 5 through the Clark inverse transformer 71.

[0121] The output end of the Park converter 32 is connected to the input end of the current difference calculator 75, and the current difference calculator 75 calculates the current difference between the dq coordinate system current and the feedback current. The current difference calculator 75 provides the current difference to the torque current regulator 73 and the excitation current regulator 74. The torque current regulator 73 performs a proportional integral torque current regulation operation on the current difference, and the excitation current regulator 74 performs a proportional integral excitation current regulation operation on the current difference to obtain the d-axis voltage and the q-axis voltage.

[0122] The Park inverse transformer 72 performs a Park inverse transformation on the d-axis voltage and the q-axis voltage to obtain a Park inverse transformation result. The Park inverse transformer 72 provides the Park inverse transformation result to the Clark inverse transformer 71, and the Clark inverse transformer 71 performs a Clark inverse transformation on the Park inverse transformation result to obtain a three-phase PWM voltage. The three-phase PWM voltage is provided to the motor 1, the u-phase wiring inputs the U-phase PWM voltage Vu to the motor 1, the v-phase wiring inputs the V-phase PWM voltage Vv to the motor 1, and the w-phase wiring inputs the W-phase PWM voltage Vw to the motor 1.

[0123] The present embodiment provides a motor power automatic tracking system, including a current sensor 2, the current sensor 2 collects the three-phase current of the motor 1, and provides the three-phase current to a coordinate system transformation module 3; the output end of the coordinate system transformation module 3 is connected to the input end of the phase angle transformation module 4, the output end of the phase angle transformation module 4 is connected to the input end of the integration module 5, and the input end of the integration module 5 is connected to the compensation end 6. The coordinate system transformation module 3 performs Clarke transformation and Park transformation on the three-phase current in sequence, and the phase angle transformation module 4 performs phase angle transformation on the phase angle to obtain the transformed phase angle. The integration module 5 integrates the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve, and the compensation end 6 adjusts the power of the motor 1 according to the compensation current curve.

[0124] Unless otherwise specifically stated, the relative arrangement, numerical expressions and numerical values ​​of the parts and steps set forth in these embodiments do not limit the scope of the application. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a restriction. Therefore, other examples of exemplary embodiments can have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, and therefore, once a certain item is defined in an accompanying drawing, it does not need to be further discussed in the subsequent accompanying drawings.

[0125] It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would then be positioned "below" or "below" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be interpreted accordingly.

[0126] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of this application.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for automatically tracking motor power, characterized in that: include: The three-phase current of the motor is collected by the current sensor, and the three-phase current includes the A-phase current i a 、B phase current i b and C phase current i c ; Performing Clarke transformation on the three-phase current to obtain αβ coordinate system current; Performing Park transformation on the αβ coordinate system current to obtain the dq coordinate system current; Comparing the dq coordinate system current with the feedback current, and generating a PWM waveform according to the comparison result; Performing phase angle transformation on the phase angle to obtain a transformed phase angle; Integrating the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve; The motor power is adjusted according to the compensation current curve.

2. The method for automatically tracking motor power according to claim 1, characterized in that: Before performing phase angle transformation on the phase angle to obtain the transformed phase angle, the method further includes: Express the phase angle in complex form; Setting the real part of the phase angle as the starting phase angle; The imaginary part of the phase angle is set to the adjusted phase angle.

3. The method for automatically tracking motor power according to claim 1, characterized in that: The step of integrating the transformed phase angle, PWM waveform and motor torque to obtain a compensation current curve comprises: Constructing a first integral function; The transformed phase angle, PWM waveform and motor torque are used as integral variables, and the first integral function is triple integrated to obtain a compensation current curve.

4. The method for automatically tracking motor power according to claim 1, characterized in that: Adjusting the motor power according to the compensation current curve includes: Get the reference current of the motor; Calculating a current difference between the compensation current curve and the reference current; The portion of the compensation current curve where the current difference is less than 0 is set as a preset current to obtain a final current curve; The motor power is adjusted according to the final current curve.

5. The method for automatically tracking motor power according to claim 1, characterized in that: The Clarke transformation of the three-phase current to obtain the αβ coordinate system current includes: The αβ coordinate system current is calculated according to the following formula: Among them, i α is the α phase current in the αβ coordinate system, i β is the β-phase current in the αβ coordinate system, and the αβ coordinate system is a two-phase stationary coordinate system.

6. The method for automatically tracking motor power according to claim 1, characterized in that: The performing Park transformation on the αβ coordinate system current to obtain the dq coordinate system current includes: The αβ coordinate system current is transformed into the dq coordinate system according to the following formula to obtain the dq coordinate system current: i d =i α cosθ+i β cosθ; i q =-i α sinθ+i β cosθ; Among them, i d is the d-axis current, i q is the q-axis current, and θ is the motor rotation angle.

7. The method for automatically tracking motor power according to claim 1, characterized in that: The step of comparing the dq coordinate system current and the feedback current and generating a PWM waveform according to the comparison result includes: Calculating the current difference between the dq coordinate system current and the feedback current; Performing proportional integral torque current adjustment operation and proportional integral excitation current adjustment operation on the current difference to obtain a d-axis voltage and a q-axis voltage; The d-axis voltage and the q-axis voltage are subjected to Park inverse transformation and Clark inverse transformation in sequence to obtain a three-phase PWM voltage.

8. A motor power automatic tracking system, characterized in that: The method for automatically tracking motor power applied to any one of claims 1 to 7, wherein the system includes a current sensor, which collects the three-phase current of the motor and provides the three-phase current to a coordinate system transformation module; the output end of the coordinate system transformation module is connected to the input end of a phase angle transformation module, the output end of the phase angle transformation module is connected to the input end of an integration module, and the output end of the integration module is connected to a compensation end.

9. The motor power automatic tracking system according to claim 8, characterized in that: The coordinate system transformation module includes a Clark transformer and a Park transformer. The output end of the current sensor is connected to the input end of the Clark transformer, and the output end of the Clark transformer is connected to the input end of the Park transformer.

10. The motor power automatic tracking system according to claim 8, characterized in that: It also includes a coordinate system inverse transformation module, which includes a Clark inverse transformer, a Park inverse transformer, a torque current regulator, an excitation current regulator and a current difference calculator, the current difference calculator is connected to the input end of the torque current regulator and the input end of the excitation current regulator, the output end of the torque current regulator and the output end of the excitation current regulator are connected to the input end of the Park inverse transformer, and the output end of the Park inverse transformer is connected to the integration module through the Clark inverse transformer.

Images