A motor control method and system considering cross-coupled inductance

Abstract

The present invention discloses a motor control method and system considering cross-coupled inductance, the method establishes a motor voltage equation considering cross-coupling; and establishes a second-order frequency adaptive observer of a hybrid excitation motor in a two-phase stationary coordinate system to obtain the estimated value of the back electromotive force of the motor; more preferably, a phase-locked loop based on a linear steady-state Kalman filter is established, and then the estimated value of the back electromotive force is input into the phase-locked loop based on the linear steady-state Kalman filter to estimate the angular velocity ω and the rotor position θ. The technical solution of the present invention suppresses the error caused by the change of inductance parameters due to the magnetic saturation effect during the operation of the motor, fully considers the influence of cross-coupled inductance, and the technical solution of the present invention has better stability, faster response speed and higher position observation accuracy than the traditional positionless sensor.

Description

Technical Field

[0001] The present invention belongs to the field of speedless control, and specifically relates to a motor control method and system taking cross-coupled inductance into consideration, and is particularly applicable to hybrid excitation motor control, with outstanding performance. Background Art

[0002] The motor is a device that realizes the conversion of electromechanical energy. It is widely used. The electrically excited synchronous motor adjusts the magnetic field by changing the magnitude of the excitation current, but the existence of excitation loss makes it difficult for the motor to work at a high efficiency. The permanent synchronous motor adjusts the d-axis current to achieve weak magnetic speed expansion, which is difficult to achieve and easily causes permanent demagnetization of the permanent magnet. Under such conditions, the concept of hybrid excitation motor came into being. It adds an electrically excited magnetic potential source on the basis of the permanent magnet excitation source. Due to its superior magnetic adjustment ability and high power density, it has broad application prospects in many fields such as aerospace, electric vehicles, etc.

[0003] High-performance motor control systems require precise rotor position, while traditional devices for detecting position signals are expensive and demanding on the working environment. By adopting a position sensorless control method, the complex speed detection device can be removed, the system cost can be reduced, and the reliability can be improved. In fact, when the motor is running, especially under high load conditions, the saturation of the internal magnetic circuit will change, and parameters such as winding inductance and permanent magnet flux will also change accordingly. The coupling between the d-axis and q-axis magnetic circuits changes the magnetic field distribution, making the magnetic field distribution of the motor not symmetrical around the d-axis. The existence of cross-coupling affects the accuracy of rotor position observation, reduces the accuracy of position observation, and affects the stability of the system. Especially in hybrid excitation motors, the impact is quite large. Summary of the invention

[0004] The technical problem to be solved by the present invention is: the existence of cross-coupling affects the accuracy of rotor position observation, reduces the accuracy of position observation, and affects the stability of the system. How to incorporate the influence of cross-coupling into the motor control process and improve the motor control performance. To this end, the technical solution of the present invention provides a motor control method and system considering cross-coupled inductance. The method considers the coupled inductance between the d-axis and q-axis magnetic circuits, incorporates it into the observer control as one of the input parameters, and designs a second-order frequency adaptive observer of the motor based on the voltage equation considering the cross-coupled inductance of the d-axis and q-axis. The cross-coupled inductance of the d-axis and q-axis is used as one of the input variables of the observer, so as to realize the incorporation of the influence of cross-coupling into the motor control process, improve the accuracy of rotor position observation, and further ensure the operating performance of the motor. The technical solution of the present invention is particularly outstanding in hybrid excitation motors.

[0005] To this end, the present invention provides the following technical solutions:

[0006] In one aspect, the present invention provides a motor control method considering cross coupling, comprising the following steps:

[0007] Establish the motor voltage equation considering the cross-coupled inductance of d and q axes;

[0008] Based on the motor voltage equation considering the cross-coupled inductance of the d and q axes, a second-order frequency adaptive observer of the motor is established in a two-phase stationary coordinate system, wherein the cross-coupled inductance of the d and q axes is one of the input variables of the second-order frequency adaptive observer;

[0009] Based on the second-order frequency adaptive observer and the phase-locked loop, the motor control is realized by utilizing the collected motor parameters;

[0010] Among them, the second-order frequency adaptive observer observes the estimated back electromotive force of the motor; the estimated back electromotive force is input into the phase-locked loop to observe the rotor position and angular velocity estimated value of the motor, and the rotor position and angular velocity estimated value enter the motor closed-loop control system to control the motor.

[0011] The traditional motor position observer does not consider the cross-coupling inductance of the d and q axes, and the existence of cross-coupling in the actual operation of the motor will affect the performance of the observer, so the technical solution of the present invention introduces cross-coupling inductance and combines it with a second-order frequency adaptive observer. This method can suppress the influence of magnetic saturation and improve the accuracy of position observation. Under high load conditions, there is a more serious magnetic saturation phenomenon, which causes the cross-coupling inductance in the motor to become larger. Putting the cross-coupling into the observer can reduce the error of position observation. Among them, the second-order frequency adaptive observer designed by the present invention is a bandpass filter. From the analysis of the BODE diagram, it can be seen that only a given angular velocity can pass, and both high and low harmonics will be subject to amplitude attenuation and phase delay, which will not affect the system.

[0012] Further optionally, the construction process of the second-order frequency adaptive observer is:

[0013] Taking the estimated value of back electromotive force as the system disturbance, establishing an auxiliary variable y for observing the estimated value of back electromotive force, wherein the auxiliary variable y is a relationship between the estimated value of back electromotive force and the current state variable, and then constructing a differential equation of the auxiliary variable y including the cross-coupled inductance of the d and q axes;

[0014] The transfer function of the second-order frequency adaptive observer is deduced by combining the motor voltage equation and the differential equation of the auxiliary variable y.

[0015] Further optionally, the auxiliary variable y is expressed as:

[0016]

[0017] The differential equation of the auxiliary variable y is expressed as:

[0018]

[0019] In the formula, y αβ is the auxiliary variable y vector matrix in the two-phase stationary coordinate system α-β; is the estimated value vector of the back electromotive force in the two-phase stationary coordinate system α-β, g is the gain of the second-order frequency adaptive observer, i αβ is the current vector matrix in the two-phase stationary coordinate system α-β; u αβ is the voltage vector matrix in the two-phase stationary coordinate system α-β, V is the matrix of cross-coupled inductances including d and q axes, R is the stator resistance, ω e is the angular velocity of the motor, L qd is the coupling inductance of the q-axis to the d-axis, k is the gain of the estimated back-electromotive force integration; L q is the equivalent inductance of the q-axis, is the flux vector matrix in the two-phase stationary coordinate system α-β, for y αβ The differential of .

[0020] Since the traditional method uses integration to directly obtain the back electromotive force but the system structure is simple and the stability is poor, the technical solution of the present invention establishes an auxiliary variable y related to the observed disturbance quantity and gives its differential form, which is used as an intermediate variable for obtaining the observed back electromotive force. A branch is added to the structure of the observer, so that the transfer function structure changes, avoiding direct integration to obtain the back electromotive force.

[0021] Further optionally, the transfer function of the second-order frequency adaptive observer is expressed as:

[0022]

[0023] In the formula, is the back-EMF estimation vector in the two-phase stationary coordinate system α-β, g is the gain of the second-order frequency adaptive observer, s = d / dt, k is the gain of the estimated back-EMF integration, is the actual back electromotive force;

[0024] The motor voltage equation based on considering the cross-coupled inductance of the d and q axes is expressed as:

[0025]

[0026] Among them, L q is the equivalent inductance of the q-axis, is the current vector matrix i in the two-phase stationary coordinate system α-β αβThe differential of αβ is the voltage vector matrix in the two-phase stationary coordinate system α-β, V is the matrix of cross-coupled inductances including d and q axes, R is the stator resistance, ω e is the angular velocity of the motor, L qd is the coupling inductance of the q-axis to the d-axis.

[0027] Further optionally, the gain of the second-order frequency adaptive observer Gain of the estimated back-EMF integral ξ is the damping ratio in the second-order system, is the estimated angular velocity.

[0028] Further optionally, before inputting into the phase-locked loop, the back electromotive force estimation value is normalized to obtain a normalized back electromotive force, which is then input into the phase-locked loop;

[0029] Among them, the normalized back EMF is expressed as:

[0030]

[0031] In the formula, is the estimated value of back EMF The normalized back EMF after normalization is: The estimated back EMF values ​​are The α and β axis components in the two-phase stationary coordinate system α-β.

[0032] Further optionally, the phase-locked loop is a phase-locked loop based on a third-order steady-state linear Kalman filter, and the prediction model of the phase-locked loop based on the third-order steady-state linear Kalman filter is expressed as:

[0033]

[0034]

[0035] In the above formula, G and θ e They are the state variable estimation matrix, state variable correction matrix, adjustment coefficient matrix and phase error respectively; g1, g2 and g3 are the gains of the adjustment system matrix, θ(λ) represents the estimated value and actual value of the rotor position; x, y, A, C, and λ are the input state variable matrix, output variable matrix, state matrix, output matrix, and sampling instant, respectively;

[0036] The state variable matrix x and the state matrix A are expressed as:

[0037] x T =[θ ω a]

[0038] Where θ, ω, a and T s They are rotor position, angular velocity, angular acceleration and sampling time;

[0039] Among them, the normalized back electromotive force is transformed from the stationary coordinate system α-β to the rotating coordinate system dq, corresponding to the q-axis component As the phase error θ representing the rotor position θ e The input is a phase-locked loop based on a third-order steady-state linear Kalman filter to observe the rotor position and angular velocity estimate of the motor.

[0040] Based on the above discrete prediction model, the expression of the phase-locked loop in the time domain is:

[0041]

[0042]

[0043] In the formula, Corresponding to the time domain functions of the angular velocity estimate and rotor position, respectively, ω(s) are the estimated and actual values ​​of angular velocity respectively; θ(s) are the estimated and actual values ​​of the rotor position in the time domain respectively.

[0044] In another aspect, the present invention further provides a motor control method based on the above control method taking into account the influence of the cross-coupling inductance of the d and q axes, comprising the following steps:

[0045] S1: Obtain motor parameters, including: three-phase voltage, three-phase current and cross-coupling inductance of d and q axes of the motor, and then transform the three-phase voltage and three-phase current of the motor by Clark transformation to obtain the voltage and current in a two-phase stationary coordinate system;

[0046] S2: The voltage and current of the motor in the two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the given value of the angular velocity of the motor are input into the constructed second-order frequency adaptive observer to observe the estimated value of the back electromotive force of the motor;

[0047] S3: Inputting the estimated back electromotive force value into a phase-locked loop to observe the rotor position and angular velocity estimation value of the motor;

[0048] S4: using the observed motor rotor position and angular velocity estimation value for motor vector control to generate a motor drive signal;

[0049] The angular velocity estimation value of the observed motor participates in the back electromotive force estimation value observation of the second-order frequency adaptive observer at the next moment.

[0050] In a third aspect, the present invention provides a system based on the above motor control method, comprising:

[0051] The motor parameter acquisition module is used to obtain the motor parameters, including: the three-phase voltage, three-phase current and cross-coupled inductance of the d and q axes of the motor, and then the three-phase voltage and three-phase current of the motor are transformed by Clark to obtain the voltage and current in the two-phase stationary coordinate system;

[0052] A second-order frequency adaptive observer is used to observe the estimated value of the back electromotive force of the motor using the voltage and current of the motor in a two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the angular velocity of the motor;

[0053] A phase-locked loop is used to observe the rotor position and angular velocity estimate of the motor using the estimated back electromotive force;

[0054] The vector control module is used to perform motor vector control using the observed motor rotor position and angular velocity estimation value, generate a motor drive signal, and control the motor.

[0055] In a fourth aspect, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program is called by a processor to implement: the above-mentioned motor control method considering cross-coupled inductance.

[0056] Beneficial Effects

[0057] Compared with the existing method, the advantages of the present invention are:

[0058] The technical solution of the present invention constructs a brand-new second-order frequency adaptive observer which considers the cross-coupled inductance of the d and q axes, and takes the cross-coupled inductance of the d and q axes as one of the input variables of the observer, so as to realize the consideration of the influence of the cross-coupled inductance of the d and q axes in the position sensorless control, incorporate the influence of the cross-coupling into the motor control process, improve the accuracy of the rotor position observation, suppress the error caused by the change of the inductance parameter due to the magnetic saturation effect during the operation of the motor, and there is no delay in the rotor position identification, and the influence of the phase jump, frequency jump and frequency ramp on the system can be suppressed, so as to have better stability, faster response speed and higher position observation accuracy than the traditional position sensorless control. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 The overall control block diagram of a hybrid excitation motor considering the cross-coupling effect according to an embodiment of the present invention;

[0060] Figure 2 A block diagram of a second-order frequency adaptive observer system using an embodiment of the present invention;

[0061] Figure 3 The output impedance Bode diagram of the second-order frequency adaptive observer using the embodiment of the present invention;

[0062] Figure 4 The system block diagram of the phase-locked loop based on the linear steady-state Kalman filter according to the embodiment of the present invention is shown. DETAILED DESCRIPTION

[0063] The present invention provides a motor control method taking cross-coupling inductance into consideration, which is used to solve the problem that the control performance needs to be improved due to the influence of cross-coupling inductance of d and q axes not being considered in the prior art. Therefore, the technical idea of ​​the present invention is applicable to any type of motor with the above technical problems. Although the hybrid excitation motor will be used as an example for explanation below, the type of motor to which the present invention is applicable is not limited thereto. The present invention will be further described below in conjunction with the embodiments.

[0064] Embodiment 1:

[0065] An embodiment of the present invention provides a motor control method for a hybrid excitation motor taking into account cross-coupling inductance. The control process of the motor control method is as follows:

[0066] S1: Obtain motor parameters, including: the three-phase voltage, three-phase current and cross-coupled inductance of the d and q axes of the motor, and then transform the three-phase voltage and three-phase current of the motor through Clark transformation to obtain the voltage and current in a two-phase stationary coordinate system.

[0067] Among them, the conversion formula of the voltage and current process in the two-phase stationary coordinate system α-β obtained by Clark transformation is as follows:

[0068]

[0069] In the formula, u a ,u b ,u c is the motor voltage in the three-phase stationary coordinate system, u α ,u β is the voltage in the two-phase stationary coordinate system α-β. It should be noted that the transformation equation of current is the same as that of voltage, C 2s / 3s It represents the conversion between the three-phase stationary coordinate system and the two-phase stationary coordinate system α-β.

[0070] S2: The voltage and current of the motor in the two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the given value of the angular velocity of the motor are input into the constructed second-order frequency adaptive observer to observe the estimated value of the back electromotive force of the motor;

[0071] S3: Inputting the estimated back electromotive force value into a phase-locked loop to observe the rotor position and angular velocity estimation value of the motor;

[0072] S4: The observed motor rotor position and angular velocity estimation value are used for motor vector control to generate a motor drive signal, and then the closed-loop control of the motor is realized according to the technical ideas of steps S1-S4.

[0073] It should be understood that one of the cores of the present invention is to construct a second-order frequency adaptive observer in step S2 to observe the estimated value of the back electromotive force of the motor, and then input it into the phase-locked loop to observe the rotor position and angular velocity estimated value of the motor. The observed angular velocity estimated value of the motor is applied to the observation process of the second-order frequency adaptive observer at the next moment, realizing a closed-loop control.

[0074] It should be noted that, based on the above control ideas, there are many existing technologies that can be implemented in the field to determine which type of phase-locked loop is used to observe the motor rotor position and angular velocity estimation value, and how to apply the motor rotor position and angular velocity estimation value to the motor closed-loop control system after obtaining the motor rotor position and angular velocity estimation value. Therefore, the present invention does not impose specific constraints on this. Among them, the present invention preferably uses a phase-locked loop based on a third-order steady-state linear Kalman filter, which will be described in detail below.

[0075] In order to fully illustrate the above control process, the embodiment of the present invention is described as follows:

[0076] like Figure 1 The motor shown adopts traditional double closed-loop control. After the speed is given, the detected three-phase current and voltage are transformed to a stationary coordinate system. The second-order frequency adaptive observer is combined with the motor model. The q-axis inductance and the cross-coupled inductance on the dq axis of the given motor are substituted into the second-order frequency adaptive observer. The back electromotive force estimation value is obtained according to the definition of the auxiliary state and the designed structure; then the back electromotive force estimation value is preferably normalized to obtain two quantities with an amplitude of 1, which are input into the third-order steady-state linear Kalman filter phase-locked loop. The phase information of the back electromotive force estimation value contains the rotor position information. After multiple operations, the estimated rotor position (rotor position) and angular velocity are obtained, and the estimated value is returned to the observer and the phase-locked loop. The estimated value replaces the actual value and is put into the motor closed-loop control system for the next operation. Through the closed-loop operation, the observer and the phase-locked loop reduce the error between the observed value and the actual value, which has a significant improvement in accuracy compared with the traditional method. Figure 1 The lower right corner is the excitation current setting module of the hybrid excitation motor. After the excitation current size is given, the output PWM duty cycle is given to the H-bridge inverter through PI control, so that the inverter outputs a given current to the excitation winding.

[0077] Figure 2 A block diagram of a second-order frequency adaptive observer system according to an embodiment of the present invention is provided. The second-order frequency adaptive observer, which is one of the core components of the present invention, will be described in detail below.

[0078] 1) Introduce back electromotive force and establish the motor voltage equation with current as the state quantity considering the cross-coupled inductance of d and q axes;

[0079]

[0080] Among them, L q is the equivalent inductance of the q axis, i α ,i β is the current in the two-phase stationary coordinate system α-β, R is the stator resistance, ω e is the angular velocity of the motor, L qd is the coupling inductance of the q-axis to the d-axis, is the back electromotive force in the two-phase stationary coordinate system α-β. It should be understood that the rotor position can be obtained based on the back electromotive force.

[0081] The above motor voltage equation can be simplified to:

[0082]

[0083] in, Represents the actual back electromotive force vector matrix and the differential vector matrix of the current in the stationary coordinate system α-β.

[0084] Since the traditional method uses integration to directly obtain the back electromotive force, but the system structure is simple and the stability is poor, in order to avoid the above problems, the technical solution of the present invention is based on the voltage equation considering the cross-coupled inductance of the d and q axes, and the back electromotive force estimation value is used as the system disturbance quantity, and an auxiliary variable y about the observed disturbance quantity is established, and its differential form is given to be used as an intermediate variable for obtaining the observed back electromotive force, and a branch is added to the structure of the observer, so that the transfer function structure changes. The auxiliary state is set to the relationship between the observed back electromotive force and the current state variable, which is expressed as:

[0085]

[0086] Among them, y αβ is the auxiliary variable y vector matrix in the two-phase stationary coordinate system α-β, is the estimated value vector of the back electromotive force in the two-phase stationary coordinate system α-β, g is the gain of the second-order frequency adaptive observer; i αβ is the current vector matrix in the two-phase stationary coordinate system α-β.

[0087] The inductance matrix V considering the cross-coupled inductance of the d and q axes is introduced, and the differential equation of the auxiliary state y is defined as:

[0088]

[0089] Where k is the gain of the estimated back-EMF integral;

[0090] It should be understood that the differential equation of the auxiliary state variable y after the introduction of the cross-coupled inductance can be obtained from equation (5). By integrating it and substituting it into (4), the observed back electromotive force can be obtained. The integral of the back electromotive force can be used to obtain the flux linkage The magnetic link It is also used in equation (5) to form a closed loop, which can realize the observation of the estimated value of back electromotive force.

[0091] In order to more clearly explain the model of the second-order frequency adaptive observer and the transfer function that characterizes the output-input of the observer, the simplified motor voltage equation (3) is substituted into the dynamic equation of y, and the intermediate quantity is eliminated. The equation (model of the second-order frequency adaptive observer) containing only the disturbance variable (estimated back electromotive force) can be obtained:

[0092]

[0093] in, is the estimated value of back EMF The actual back EMF The error, is the estimated value of back EMF The differential vector matrix of .

[0094] According to the model of the second-order frequency adaptive observer, by performing Lapalce transformation on equation (6), the transfer function between the back EMF observed by the second-order frequency adaptive observer and the actual back EMF in the time domain can be obtained as follows:

[0095]

[0096] Where s = d / dt, according to the form of a typical second-order system in automatic control principles, the gain of the observer is obtained Gain of disturbance ξ is the damping ratio in the second-order system, is the estimated value of angular velocity. When the angular velocity is determined, the dynamic performance of the system is determined by ξ. When , the system has better dynamic performance. Since the observer signal may decay at low speed, in order to avoid the weak back EMF signal at zero low speed, when the estimated angular velocity is less than or equal to 100, the observer gain g is taken as 200ξ.

[0097] It should be understood that formula (7) represents the functional relationship between the output of the observer (the estimated value of the back electromotive force) and the input of the observer (the actual value of the back electromotive force), and is a second-order system.

[0098] In summary, the traditional motor position observer does not consider the cross-coupled inductance of the d and q axes, and the presence of cross-coupling during the actual operation of the motor will affect the performance of the observer. To this end, the technical solution of the present invention introduces cross-coupled inductance and combines it with a second-order frequency adaptive observer, which can effectively suppress the influence of magnetic saturation and improve the accuracy of position observation. Under high load conditions, there is a more serious magnetic saturation phenomenon, which causes the cross-coupled inductance in the motor to become larger. Putting cross-coupling into the observer can reduce the error of position observation.

[0099] Figure 3 The output impedance Bode diagram of the second-order frequency adaptive observer using the embodiment of the present invention is shown in the figure. It can be seen from the figure that the observer can effectively extract the target frequency and suppress the harmonic interference of other frequencies. The smaller the value of ξ, the smaller the bandwidth, and the better the harmonic suppression effect near the specific sub-frequency, but its response speed will be slower. The higher the damping ratio ξ, the higher the harmonic content.

[0100] Figure 4 The system block diagram of the phase-locked loop based on the linear steady-state Kalman filter using the embodiment of the present invention is as follows: the estimated back electromotive force / extended flux is transformed into the dq coordinate system and substituted into the mathematical model of the linear steady-state Kalman filter to obtain the observed rotor position information.

[0101] In this embodiment, before the back EMF estimation value is input into the phase-locked loop, the observed back EMF value is preferably normalized to obtain the normalized back EMF, so as to effectively suppress the influence of harmonics and parameter changes during motor operation on the observed back EMF amplitude.

[0102] Among them, the normalized back EMF is:

[0103]

[0104] In the formula, is the estimated value of back EMF The normalized back EMF after normalization is: The estimated back EMF values ​​are The α and β axis components in the two-phase stationary coordinate system α-β.

[0105] It should be understood that the normalized back EMF is transformed from the stationary coordinate system to the rotating coordinate system (dq) and the q-axis component is selected. As the phase error of the phase-locked loop θ e Input, as follows:

[0106]

[0107] Among them, θ eis the phase error. When the observed rotor position is equal to the actual rotor position, the phase error in the above formula is equal to 0.

[0108] The present invention preferably establishes a phase-locked loop based on a third-order steady-state linear Kalman filter and designs Kalman filter related parameters, including:

[0109] The prediction unit of the phase-locked loop can be described as:

[0110]

[0111] Among them, x, y, A, C and λ are the input variable matrix, output variable matrix, state matrix, output matrix and sampling moment respectively, and their matrix forms are as follows:

[0112] x T =[θ ω a] C=[1 0 0

[0113] θ, ω, a and T in the matrix s They are rotor position, angular velocity, angular acceleration and sampling time. Based on the prediction unit, there is also a state correction unit:

[0114]

[0115] In the above formula G and θ e They are state estimation variables, state correction variables, adjustment coefficient matrix and phase error. The adjustment coefficient matrix and phase error are:

[0116]

[0117] Among them, g1, g2 and g3 are the gains of the adjustment matrix. is the rotor position estimated by the system, and θ(λ) is the actual rotor position. Combining equations (10) and (11), we can know the observation principle of the phase-locked loop, that is, the normalized back electromotive force is transformed from the stationary coordinate system α-β to the rotating coordinate system dq, corresponding to the q-axis component As the phase error θ representing the rotor position θ e The state estimated variables are input into the phase-locked loop, and the rotor position estimated value and angular velocity estimated value can be obtained based on the calculation of the above state estimated variables.

[0118] The estimated normalized back EMF is input into the phase-locked loop based on the linear steady-state Kalman filter to estimate the angular velocity ω and the rotor position θ. After multiple operations, the expression of the phase-locked loop in the time domain can be obtained as follows:

[0119]

[0120]

[0121] In this embodiment, the cutoff frequency ω of the given system c , analyze the zero-pole distribution of the closed-loop transfer function and set the parameters: g1 = bω c ,g2=bω c 2 ,g3=ω c 3 , b=1.414. Since the above phase-locked loop is a third-order system, it can be seen from the transfer function that zero steady-state error can be achieved when the input is a frequency ramp.

[0122] In summary, the rotor position is obtained through multiple calculations, which is an operation between the estimated value and the actual value, so that the estimated value is close to the actual value, which is completed by adjusting the matrix and phase correction. The transfer function between this structure is shown above. Because the back electromotive force estimate contains the rotor position information, it is directly input into the phase-locked loop, which is equivalent to inputting the angle, and then obtaining the estimated angle through the phase-locked loop, and then treating it as input and putting it into the phase-locked loop to calculate the next round, and finally making the estimated speed and angle equal to the given one.

[0123] It should be noted that the commonly used sliding mode speedless control method usually uses a low-pass filter to extract the fundamental component of the back electromotive force. The filtering performance of the low-pass filter is poor, which will produce phase delay and cannot effectively suppress the harmonic interference caused by cross-coupling. In addition, most traditional phase-locked loop solutions use a proportional-integral controller as a loop filter. When this structure is used, when the input is a frequency ramp, the speed-free estimation solution cannot achieve zero steady-state error. Therefore, the traditional speed estimation solution based on the phase-locked loop may have estimation errors under certain operating conditions. The technical solution of the present invention can effectively overcome the above problems and bring significant progress.

[0124] It should also be noted that the above-mentioned embodiment 1 is described by taking a hybrid excitation motor as an example. The hybrid excitation motor has an additional set of windings in the motor model, but all the above-mentioned formulas are universal and do not involve newly added windings. Therefore, the above-mentioned formulas are not limited to hybrid excitation motors, and are applicable to motor models with cross-coupling effects.

[0125] Therefore, the technical idea of ​​a motor control method considering cross-coupling in the technical solution of the present invention can also be summarized as follows:

[0126] Establish the motor voltage equation considering the cross-coupled inductance of d and q axes;

[0127] Based on the motor voltage equation considering the cross-coupled inductance of the d and q axes, a second-order frequency adaptive observer of the motor is established in a two-phase stationary coordinate system, wherein the cross-coupled inductance of the d and q axes is one of the input variables of the second-order frequency adaptive observer;

[0128] Based on the second-order frequency adaptive observer and the phase-locked loop, the motor control is realized by utilizing the collected motor parameters.

[0129] In some embodiments, the present invention further provides a system based on a motor control method, comprising:

[0130] The motor parameter acquisition module is used to obtain the motor parameters, including: the three-phase voltage, three-phase current and cross-coupled inductance of the d and q axes of the motor, and then the three-phase voltage and three-phase current of the motor are transformed by Clark to obtain the voltage and current in the two-phase stationary coordinate system;

[0131] A second-order frequency adaptive observer is used to observe the estimated value of the back electromotive force of the motor using the voltage and current of the motor in a two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the angular velocity of the motor;

[0132] A phase-locked loop is used to observe the rotor position and angular velocity estimate of the motor using the estimated back electromotive force;

[0133] The vector control module is used to perform motor vector control using the observed motor rotor position and angular velocity estimation value, generate a motor drive signal, and control the motor.

[0134] It should be noted that there are many feasible ways to construct the vector control module, such as Figure 1 As shown, it includes a speed outer loop, a speed loop PI regulator, a current inner loop, a current inner loop PI regulator, an SVPWM modulation module, and an inverter, which are connected in sequence. After obtaining the three-phase current, rotor position information, and speed, an IPMSM dual closed-loop vector control module is formed, and the required voltage vector drive IPMSM is generated through vector control. It should be understood that this implementation process is only an example. When different control modes are adopted after obtaining the rotor position and angular velocity, the composition of the corresponding vector control module also changes accordingly, and the present invention does not make specific limitations on this.

[0135] It should be understood that the connection relationship and signal transmission relationship between the above elements in this embodiment can be specifically referred to Figure 1 .

[0136] In some embodiments, the present invention further provides a computer-readable storage medium storing a computer program, wherein the computer program is called by a processor to implement: the above-mentioned motor control method considering cross-coupled inductance. The implementation process of each step can refer to the above-mentioned method content, and the present invention does not specifically limit this.

[0137] It should be understood that the implementation process of some steps and whether to execute some steps and the execution order can refer to the implementation process of the aforementioned embodiment.

[0138] The readable storage medium is a computer-readable storage medium, which may be an internal storage unit of the controller described in any of the foregoing embodiments, such as a hard disk or memory of the controller. The readable storage medium may also be an external storage device of the controller, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the controller. Further, the readable storage medium may also include both an internal storage unit of the controller and an external storage device. The readable storage medium is used to store the computer program and other programs and data required by the controller. The readable storage medium may also be used to temporarily store data that has been output or is to be output.

[0139] Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned readable storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0140] It should be emphasized that the examples described in the present invention are illustrative rather than restrictive, and therefore the present invention is not limited to the examples described in the specific embodiments. Any other embodiments derived by those skilled in the art based on the technical solution of the present invention that do not depart from the purpose and scope of the present invention, whether modified or replaced, also fall within the scope of protection of the present invention.

Claims

1. A motor control method considering cross-coupled inductance, characterized in that: The following steps are involved: Establish the motor voltage equation considering the cross-coupled inductance of d and q axes; Based on the motor voltage equation considering the cross-coupled inductance of the d and q axes, a second-order frequency adaptive observer of the motor is established in a two-phase stationary coordinate system, wherein the cross-coupled inductance of the d and q axes is one of the input variables of the second-order frequency adaptive observer; Based on the second-order frequency adaptive observer and the phase-locked loop, the motor control is realized by utilizing the collected motor parameters; Among them, the second-order frequency adaptive observer observes the estimated back electromotive force of the motor; the estimated back electromotive force is input into the phase-locked loop to observe the rotor position and angular velocity estimated value of the motor, and the rotor position and angular velocity estimated value enter the motor closed-loop control system to control the motor.

2. The method according to claim 1, characterized in that: The construction process of the second-order frequency adaptive observer is: Taking the estimated value of back electromotive force as the system disturbance, establishing an auxiliary variable y for observing the estimated value of back electromotive force, wherein the auxiliary variable y is a relationship between the estimated value of back electromotive force and the current state variable, and then constructing a differential equation of the auxiliary variable y including the cross-coupled inductance of the d and q axes; The transfer function of the second-order frequency adaptive observer is deduced by combining the motor voltage equation and the differential equation of the auxiliary variable y.

3. The method according to claim 2, characterized in that: The auxiliary variable y is expressed as: The differential equation of the auxiliary variable y is expressed as: In the formula, y αβ is the auxiliary variable y vector matrix in the two-phase stationary coordinate system α-β; is the estimated value vector of the back electromotive force in the two-phase stationary coordinate system α-β, g is the gain of the second-order frequency adaptive observer, i αβ is the current vector matrix in the two-phase stationary coordinate system α-β; u αβ is the voltage vector matrix in the two-phase stationary coordinate system α-β, V is the matrix of cross-coupled inductances including d and q axes, R is the stator resistance, ω e is the angular velocity of the motor, L qd is the coupling inductance of the q-axis to the d-axis, k is the gain of the estimated back-electromotive force integration; L q is the equivalent inductance of the q-axis, is the flux vector matrix in the two-phase stationary coordinate system α-β, for y αβ The differential of .

4. The method according to claim 2, characterized in that: The transfer function of the second-order frequency adaptive observer is expressed as: In the formula, is the back-EMF estimation vector in the two-phase stationary coordinate system α-β, g is the gain of the second-order frequency adaptive observer, s = d / dt, k is the gain of the estimated back-EMF integration, is the actual back electromotive force; The motor voltage equation based on considering the cross-coupled inductance of the d and q axes is expressed as: Among them, L q is the equivalent inductance of the q-axis, is the current vector matrix i in the two-phase stationary coordinate system α-β αβ The differential of αβ is the voltage vector matrix in the two-phase stationary coordinate system α-β, V is the matrix of cross-coupled inductances including d and q axes, R is the stator resistance, ω e is the angular velocity of the motor, L qd is the coupling inductance of the q-axis to the d-axis.

5. The method according to claim 4, characterized in that: Gain of the second-order frequency adaptive observer Estimated back-EMF integral gain ξ is the damping ratio in the second-order system, is the estimated angular velocity.

6. The method according to claim 1, characterized in that: Before inputting into the phase-locked loop, the estimated value of the back electromotive force is normalized to obtain a normalized back electromotive force, and then inputted into the phase-locked loop; Among them, the normalized back EMF is expressed as: In the formula, Estimated value of back electromotive force The normalized back EMF after normalization is: The estimated back EMF values ​​are The α and β axis components in the two-phase stationary coordinate system α-β.

7. The method according to claim 6, characterized in that: The phase-locked loop is a phase-locked loop based on a third-order steady-state linear Kalman filter, and the prediction model of the phase-locked loop based on a third-order steady-state linear Kalman filter is expressed as: In the above formula, G and θ e They are the state variable estimation matrix, state variable correction matrix, adjustment coefficient matrix and phase error respectively; g1, g2 and g3 are the gains of the adjustment system matrix, θ(λ) represents the estimated value and actual value of the rotor position; x, A, and λ are the input state variable matrix, state matrix, and sampling instant, respectively; The state variable matrix x and the state matrix A are expressed as: x T =[θ ω a] Where θ, ω, a and T s They are rotor position, angular velocity, angular acceleration and sampling time; Among them, the normalized back electromotive force is transformed from the stationary coordinate system α-β to the rotating coordinate system dq, corresponding to the q-axis component As the phase error θ representing the rotor position θ e The input is a phase-locked loop based on a third-order steady-state linear Kalman filter to observe the rotor position and angular velocity estimate of the motor.

8. A motor control method based on any one of claims 1 to 7, characterized in that: The following steps are involved: S1: Obtain motor parameters, including: three-phase voltage, three-phase current and cross-coupling inductance of d and q axes of the motor, and then transform the three-phase voltage and three-phase current of the motor by Clark transformation to obtain the voltage and current in a two-phase stationary coordinate system; S2: The voltage and current of the motor in the two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the given value of the angular velocity of the motor are input into the constructed second-order frequency adaptive observer to observe the estimated value of the back electromotive force of the motor; S3: Inputting the estimated back electromotive force value into a phase-locked loop to observe the rotor position and angular velocity estimation value of the motor; S4: using the observed motor rotor position and angular velocity estimation value for motor vector control to generate a motor drive signal; The angular velocity estimation value of the observed motor participates in the back electromotive force estimation value observation of the second-order frequency adaptive observer at the next moment.

9. A control system based on the method of claim 8, characterized in that: The motor parameter acquisition module is used to obtain the motor parameters, including: the three-phase voltage, three-phase current and cross-coupled inductance of the d and q axes of the motor, and then the three-phase voltage and three-phase current of the motor are transformed by Clark to obtain the voltage and current in the two-phase stationary coordinate system; A second-order frequency adaptive observer is used to observe the estimated value of the back electromotive force of the motor using the voltage and current of the motor in a two-phase stationary coordinate system, the cross-coupled inductance of the d and q axes, and the angular velocity of the motor; A phase-locked loop is used to observe the rotor position and angular velocity estimate of the motor using the estimated back electromotive force; The vector control module is used to perform motor vector control using the observed motor rotor position and angular velocity estimation value, generate a motor drive signal, and control the motor.

10. A computer-readable storage medium, characterized in that: A computer program is stored, which is called by a processor to implement: The method according to any one of claims 1 to 8.

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