A model predictive current control method for switched reluctance motor with flux linkage loop

Abstract

The application discloses a kind of switch reluctance motor model predictive current control methods with flux linkage ring, comprising: the current of stator, the speed of rotor and the position of rotor are measured, the sector of judging synthetic flux linkage is distributed, and the 2 control vectors of traversal are selected in combination with flux linkage hysteresis loop signal;Through motor model, state equation and each sampling parameter, the current after using 2 control vectors is respectively predicted and calculated.The predicted current is compared in evaluation function, which one is closer to the given predicted current after using 2 vectors, and the switching state corresponding to the vector is input into power converter to control switch reluctance motor.The application combines flux linkage hysteresis loop and synthetic flux linkage sector judgment to select traversal switching state, reduces 27 kinds of switching state to 2 kinds, so as to greatly reduce the system calculation pressure, and the method has important application value in the field of high-precision servo drive of switch reluctance motor.

Description

Technical Field

[0001] This invention relates to the field of switched reluctance motor control technology, specifically to a model predictive current control method for a switched reluctance motor with a magnetic flux linkage. Background Technology

[0002] Switched reluctance motors have advantages such as simple structure, high mechanical strength, and strong robustness. However, due to the motor's doubly salient pole structure, nonlinear changes in the magnetic circuit, and the characteristics of split-phase excitation, the motor experiences significant torque ripple during operation.

[0003] Model predictive control (MRC) has gained increasing attention in power converter control algorithms due to its advantages such as simple logic, ease of handling nonlinear and multivariable systems. Based on the controller's state combinations and the physical characteristics of the controlled object, MRC can directly generate power converter drive signals based on prediction results, easily reducing the operating frequency of switching devices and providing fast dynamic response. However, MRC also has some drawbacks. When constructing the cost function, the inconsistent dimensions of the multivariable system necessitate extensive simulation experiments to design appropriate weight coefficients for each variable, reducing the algorithm's reliability and versatility. Furthermore, the large computational load is also a drawback, as the controller needs to predict every converter state, placing high demands on the DSP's computing power. Therefore, traditional MRC requires traversing a large number of switching state combinations for each prediction, placing high demands on the system's computational capabilities. This invention proposes a model predictive current control method for switched reluctance motors based on direct torque control, reducing the 27 candidate voltage vectors required by the original current prediction algorithm to only 2, significantly reducing the experimental computational load, lowering hardware requirements, and making it easier to implement. This method has significant application value in the field of high-precision servo drives for switched reluctance motors. Summary of the Invention

[0004] The purpose of this invention is to provide a model predictive current control method for a switched reluctance motor with a magnetic linkage, which reduces the 27 switching states that need to be traversed in traditional model predictive current control to 2.

[0005] To achieve the above functions, this invention designs a model predictive current control method for a switched reluctance motor with a magnetic flux linkage, executing the following steps S1-S11 to complete the control of the switched reluctance motor:

[0006] Step S1: Collect data of the switched reluctance motor at time k, including stator voltage, current, rotor speed, and rotor position angle;

[0007] Step S2: Based on the collected data of the switched reluctance motor at time k, establish a flux linkage model and obtain the three-phase flux linkage values ​​at time k;

[0008] Step S3: Referring to the direct torque control sector judgment method, the sector is determined by performing flux transformation based on the three-phase flux linkage value at time k. According to the vector selection method of direct torque control, each sector has 4 candidate vectors, namely the vector that increases flux linkage when torque increases, the vector that decreases flux linkage when torque increases, the vector that increases flux linkage when torque decreases, and the vector that decreases flux linkage when torque decreases.

[0009] Step S4: Divide the four candidate vectors of the sector obtained in step S3 into two categories: one category is vectors that increase the flux linkage, with two candidate vectors; the other category is vectors that decrease the flux linkage, with two candidate vectors. Based on the flux linkage hysteresis signal, determine whether the flux linkage needs to be increased or decreased, select the corresponding two candidate vectors, and use the two voltage vectors corresponding to the candidate vectors as the vectors to be traversed.

[0010] Step S5: The target torque value T obtained through PI control e,ref The reference torque value T for each phase at time k+1 is obtained through the torque distribution function. ref (k+1);

[0011] Step S6: Obtain the correspondence between torque, stator current, and rotor position angle through finite element simulation, and plot it as a torque-current-angle table T(i, θ). Find the torque value from the table using the values ​​of stator current and rotor position angle; based on the reference torque value T for each phase at time k+1... ref (k+1), the angle θ(k+1) of each phase at time k+1, and the reference current value i of each phase at time k+1 obtained by using the reverse lookup table algorithm on the torque-current-angle table T(i, θ) to obtain the current-torque-angle table i(T, θ). ref (k+1);

[0012] Step S7: Construct a prediction model to predict the current at time k+1 after using a certain voltage vector. Input the two voltage vectors selected in step S4 into the prediction model to obtain the predicted current values ​​i at time k+1 corresponding to the two voltage vectors. pre (k+1);

[0013] Step S8: Obtain the predicted current value i at time k+1 obtained in step S7. pre (k+1) are respectively compared with the reference current value i of each phase at time k+1 obtained in step S6. ref (k+1) are compared;

[0014] Step S9: Predict the current value i at time k+1 pre The reference current values ​​i for each phase at time (k+1) and k+1. ref(k+1), construct the evaluation function, and select the predicted current value that minimizes the evaluation function value;

[0015] Step S10: Send the switching signal corresponding to the selected predicted current value, i.e. the optimal switching state, to the three-phase unbalanced bridge converter.

[0016] Step S11: The three-phase unbalanced bridge converter controls the switched reluctance motor according to the received switching signal.

[0017] As a preferred technical solution of the present invention, the magnetic flux linkage model described in step S2 is as follows:

[0018] ψ(k)=L q i(k)+[L dsat i(k)+A(1-e -Bi(k) )-L q i(k)]f(θ(k))

[0019] Where ψ(k) is the flux linkage at time k, i(k) is the stator current at time k, θ(k) is the rotor position angle at time k, and L q It is an inductor in an misaligned position, L dsat The current i at the alignment position m The corresponding inductance value, i m It is the maximum current in the stator winding, and A and B in the formula are expressed as follows:

[0020]

[0021] f(θ) can be expressed as follows:

[0022]

[0023] Where L d The stator current i is less than the saturation phase current i. s Inductance at time, ψ m is i=i m magnetic flux at time, N r It is the number of rotor poles.

[0024] As a preferred embodiment of the present invention, the magnetic flux transformation method in step S3 is as follows:

[0025] ψ α =ψ a -ψ b cos 60°-ψ c cos 60°

[0026] ψ β =ψ b sin 60°-ψ csin 60°

[0027]

[0028]

[0029] Where ψ a , ψ b , ψ c For a three-phase magnetic flux linkage, |ψ s | is for synthesized magnetic flux.

[0030] As a preferred technical solution of the present invention: the method for determining whether the flux linkage needs to be increased or decreased in step S4 is as follows: by comparing the given flux linkage with the synthesized flux linkage through the flux linkage hysteresis signal, if the given flux linkage is greater than the synthesized flux linkage, it means that the flux linkage needs to be increased; if the given flux linkage is less than the synthesized flux linkage, it means that the flux linkage needs to be decreased.

[0031] As a preferred embodiment of the present invention, the torque distribution function in step S5 is as follows:

[0032]

[0033] Where θ is the rotor position angle, θ on Let θ be the opening angle. off For the shut-off angle, θ ov Let t be the angle of overlap. r =2π / N r For a 12 / 8 phase switched reluctance motor, t r =π / 4.

[0034] As a preferred technical solution of the present invention, the specific method of step S7 is as follows:

[0035] The phase voltage equation of the switched reluctance motor is expressed as:

[0036]

[0037] Where v is the voltage across the phase winding, i is the stator winding current of that phase, R is the phase winding resistance, and ψ is the phase flux linkage;

[0038] Meanwhile, the flux linkage is a function related to the stator current and the rotor position angle. Taking the partial derivative of the above equation for the flux linkage, we get the following equation, which can be expressed as:

[0039]

[0040] Using a first-order forward difference to approximate the discretization of di / dt in the above equation, it can be expressed as:

[0041]

[0042] Where i(k+1) is the stator current at time k+1;

[0043] The predicted current at time k+1 is as follows:

[0044]

[0045] Where ω=dθ / dt, v(k) is expressed as:

[0046] v(k)=uV dc

[0047] Where V dc denoted as bus voltage, u represents the switching state, and u is selected from 1, 0, and -1.

[0048] As a preferred embodiment of the present invention, the evaluation function in step S9 is as follows:

[0049] J(U k+1 )=(i ref (k+1)-i pre (k+1)) 2

[0050] In the formula, J(U k+1 ) represents the evaluation function.

[0051] Beneficial effects: Compared with the prior art, the advantages of the present invention include:

[0052] This invention proposes a model predictive current control method for a switched reluctance motor with a flux linkage. It uses a cubic torque distribution function to distribute the torques of each component, maintaining a constant total torque. This avoids the adjustment of weight coefficients in traditional model predictive control. By combining flux linkage hysteresis signal judgment with the vector selection method of direct torque control, it only considers two candidate voltage vectors, avoiding the need to traverse 27 voltage vectors in each prediction calculation, thus greatly reducing the computational load, lowering hardware requirements, and making it easier to implement. Attached Figure Description

[0053] Figure 1 This is an overall system structure block diagram provided according to an embodiment of the present invention;

[0054] Figure 2 This is a diagram of a three-phase asymmetrical half-bridge structure used in a switched reluctance motor according to an embodiment of the present invention.

[0055] Figure 3 This is a magnetic flux 3 / 2 transformation provided according to an embodiment of the present invention;

[0056] Figure 4 This is a sector division and vector setting diagram provided according to an embodiment of the present invention;

[0057] Figure 5This is a magnetic flux vector trajectory diagram provided according to an embodiment of the present invention;

[0058] Figure 6 It is a cubic TSF provided according to an embodiment of the present invention;

[0059] Figure 7 These are three modes of asymmetric half-bridge topology provided according to embodiments of the present invention;

[0060] Figure 8 This is a flowchart of the current prediction algorithm provided according to an embodiment of the present invention. Detailed Implementation

[0061] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0062] This invention provides a model predictive current control method for a switched reluctance motor with a magnetic flux linkage. The method executes steps S1-S11 to complete the control of the switched reluctance motor. The overall system structure block diagram is shown below. Figure 1 This invention employs a three-phase switched reluctance motor, and the power converter uses... Figure 2 The three-phase asymmetric half-bridge structure is shown.

[0063] Step S1: Collect data of the switched reluctance motor at time k, including stator voltage, current, rotor speed, and rotor position angle;

[0064] Step S2: Based on the collected data of the switched reluctance motor at time k, establish a flux linkage model and obtain the three-phase flux linkage values ​​at time k;

[0065] The flux linkage model is as follows:

[0066] ψ(k)=L q i(k)+[L dsat i(k)+A(1-e -Bi(k) )-L q i(k)]f(θ(k))

[0067] Where ψ(k) is the flux linkage at time k, i(k) is the stator current at time k, θ(k) is the rotor position angle at time k, and L q It is an inductor in an misaligned position, L dsat The current i at the alignment position m The corresponding inductance value, i m It is the maximum current in the stator winding, and A and B in the formula are expressed as follows:

[0068]

[0069] f(θ) can be expressed as follows:

[0070]

[0071] Where L d The stator current i is less than the saturation phase current i. s Inductance at time, ψ m is i=i m magnetic flux at time, N r It is the number of rotor poles.

[0072] Step S3: Referring to the direct torque control sector judgment method, perform flux transformation using the three-phase flux linkage values ​​at time k, referring to... Figure 3 The sector in which it is located is determined. According to the vector selection method of direct torque control, there are 4 candidate vectors for each sector, namely the vector that increases the flux linkage when the torque increases, the vector that decreases the flux linkage when the torque increases, the vector that increases the flux linkage when the torque decreases, and the vector that decreases the flux linkage when the torque decreases.

[0073] The flux linkage transformation is performed using the three-phase flux linkage values ​​at time k. The flux linkage transformation method is as follows:

[0074] ψ α =ψ a -ψ b cos 60°-ψ c cos 60°

[0075] ψ β =ψ b sin 60°-ψ c sin 60°

[0076]

[0077]

[0078] Where ψ a , ψ b , ψ c For a three-phase magnetic flux linkage, |ψ s | is for synthesized magnetic flux.

[0079] The reference direct torque control divides the electrical space into 6 sectors, such as... Figure 3 As shown, the sector can be determined by θ, and the basis for the determination is shown in Table 1.

[0080] Table 1

[0081]

[0082] After determining the sector, and referring to the vector selection method of traditional direct torque control, from the basic 27 control vectors, firstly, control vector combinations where two-phase or three-phase windings are all 1, 0, or -1, such as (1,1,1) and (0,0,0), are eliminated. Secondly, according to the "two-step commutation principle," and ensuring that the switching state of each phase winding cannot directly change from "1" to "-1," but must pass through a freewheeling "0" state, the impact of switching action on torque is minimized. If the switching state changes directly from "1" to "-1," it will produce a large voltage jump, increasing torque ripple. Simultaneously, each voltage vector is kept to have the same amplitude, spaced at 60-degree intervals, and located at axially symmetrical points in the six sectors. After these constraints, six effective control vectors are finally obtained, as shown in Table 2.

[0083] Table 2

[0084]

[0085] The voltage vector combinations selected in Table 2 are processed to obtain the corresponding values ​​Vα and Vβ in the stationary coordinate system, as shown in Table 3. Referring to Table 3, six voltage vectors with the same amplitude and a phase difference of 60 degrees are defined. These six control vectors are placed in equally divided electrical spaces, as follows: Figure 4 As shown.

[0086] Table 3

[0087]

[0088]

[0089] Electromagnetic torque is obtained by taking the partial angular derivative of the magnetic coenergy, as shown in the following equation:

[0090]

[0091] Reference Figure 4 As can be seen, taking counterclockwise rotation of the motor as an example, to increase torque, a voltage vector whose stator flux linkage leads the rotor's rotation direction needs to be selected; to decrease torque, a voltage vector whose stator flux linkage lags the rotor's rotation direction needs to be selected. If the flux linkage is located in the k-th region at a certain moment, Vk+1 or Vk+2 can be selected to increase torque, and Vk-1 or Vk-2 to decrease torque. With counterclockwise rotation as the positive direction, Vk+1 is the vector following Vk, and Vk-1 is the vector preceding Vk. Taking V1 as an example, Vk+1 is V2, and Vk-2 is V5. Taking k=1 as an example, if torque needs to be increased, V2 and V3 should be selected; if torque needs to be decreased, V6 and V5 should be selected.

[0092] Meanwhile, the magnitude of the change in stator flux linkage depends on the magnitude and duration of the voltage vector acting on the stator windings. The length of the voltage vector determines the rate of change in flux linkage amplitude, while the direction of the voltage vector determines the direction of flux linkage change; typically, the direction of flux linkage change is the same as the direction of the selected voltage vector. For example... Figure 5 As shown in the flux linkage vector trajectory, selecting a voltage vector with an obtuse angle to the flux linkage vector will decrease the flux linkage amplitude. If the flux linkage at a certain moment is located in the k-th region, Vk+1 or Vk-1 can be selected to increase the flux linkage, and Vk+2 or Vk-2 can be selected to decrease it. Counterclockwise rotation is taken as the positive direction. Vk+1 is the vector following Vk, and Vk-1 is the vector preceding Vk. Taking V1 as an example, Vk+1 is V2, and Vk-1 is V6; the same applies to Vk+2 and Vk-2. Taking k=1 as an example, if we need to increase the flux linkage, we can select V2 or V6; if we need to decrease the flux linkage, we should select V3 or V5. Based on the above principles, each sector has four candidate vectors: vectors that increase the flux linkage by increasing torque, vectors that decrease the flux linkage by increasing torque, vectors that increase the flux linkage by decreasing torque, and vectors that decrease the flux linkage by decreasing torque, as shown in Table 4.

[0093] Table 4

[0094]

[0095] Step S4: Divide the four candidate vectors of the sector obtained in step S3 into two categories: one category is vectors that increase the flux linkage, with two candidate vectors; the other category is vectors that decrease the flux linkage, with two candidate vectors. Based on the flux linkage hysteresis signal, determine whether the flux linkage needs to be increased or decreased, select the corresponding two candidate vectors, and use the two voltage vectors corresponding to the candidate vectors as the vectors to be traversed.

[0096] By comparing the given flux linkage with the synthesized flux linkage using the flux linkage hysteresis signal, if the given flux linkage is greater than the synthesized flux linkage, the flux linkage needs to be increased; if the given flux linkage is less than the synthesized flux linkage, the flux linkage needs to be decreased. Based on this determination of flux linkage increase or decrease, and combined with sector division and Table 4, Tables 5(a) and 5(b) are generated, as follows:

[0097] Table 5(a)

[0098]

[0099] Table 5(b)

[0100]

[0101] Each prediction is determined by the flux linkage hysteresis signal. If the flux linkage needs to be increased, Table 5(a) is selected; if the flux linkage needs to be decreased, Table 5(b) is selected. Then, two candidate vectors are selected based on the sector they are in, and these two candidate voltage vectors are used as the vectors to be traversed.

[0102] Step S5: The target torque value T obtained through PI control e,ref The reference torque value T for each phase at time k+1 is obtained through the torque distribution function. ref (k+1);

[0103] Adopting such Figure 6 The cubic torque distribution function shown distributes the torque of each phase. The reference current for each phase is obtained through the distributed torque. The model predicts the current control to achieve the desired combined torque, maintaining a constant total torque. The torque distribution function is as follows:

[0104]

[0105] Where θ is the rotor position angle, θ on Let θ be the opening angle. off For the shut-off angle, θ ov Let t be the angle of overlap. r =2π / N r For a 12 / 8 phase switched reluctance motor, t r =π / 4.

[0106] Step S6: Obtain the correspondence between torque, stator current, and rotor position angle through finite element simulation, and plot it as a torque-current-angle table T(i, θ). Find the torque value from the table using the values ​​of stator current and rotor position angle; based on the reference torque value T for each phase at time k+1... ref (k+1), the angle θ(k+1) of each phase at time k+1, and the reference current value i of each phase at time k+1 obtained by using the reverse lookup table algorithm on the torque-current-angle table T(i, θ) to obtain the current-torque-angle table i(T, θ). ref (k+1); The angle at time k+1 can be expressed as:

[0107] θ(k+1)=θ(k)+ωT s

[0108] Where ω is the rotor angular velocity, and T s The sampling period;

[0109] Step S7: Construct a prediction model to predict the current at time k+1 after using a certain voltage vector. Input the two voltage vectors selected in step S4 into the prediction model to obtain the predicted current values ​​i at time k+1 corresponding to the two voltage vectors.pre (k+1);

[0110] The specific method for step S7 is as follows:

[0111] The phase voltage equation of the switched reluctance motor is expressed as:

[0112]

[0113] Where v is the voltage across the phase winding, i is the stator winding current of that phase, R is the phase winding resistance, and ψ is the phase flux linkage;

[0114] Meanwhile, the flux linkage is a function related to the stator current and the rotor position angle. Taking the partial derivative of the above equation for the flux linkage, we get the following equation, which can be expressed as:

[0115]

[0116] Using a first-order forward difference to approximate the discretization of di / dt in the above equation, it can be expressed as:

[0117]

[0118] Where i(k+1) is the stator current at time k+1;

[0119] The predicted current at time k+1 is as follows:

[0120]

[0121] Where ω = dθ / dt;

[0122] like Figure 7 Taking phase A as an example, there are two main switching devices, S1 and S2, and two diodes. When both switches S1 and S2 are closed and conducting, the DC power supply Vdc is applied to both ends of the phase A winding through the two main switches, as follows: Figure 7 (a) The arrow indicates the direction of phase current flow; when only one of S1 and S2 is turned off, an energy release circuit is formed by a main switch, a diode, and the A-phase winding, as shown in the figure. Figure 7 As shown in (b); when both switches S1 and S2 are off, since the winding current will not reverse, the DC power supply is applied to the two ends of the winding through the two diodes, as follows: Figure 7 As shown in (c). Therefore, ignoring the forward voltage drop of the main switching devices and diodes, each phase has three operating modes: positive voltage excitation, zero voltage demagnetization, and negative voltage demagnetization, corresponding to switching states of 1, 0, and -1, respectively. The relationship between v(k) and the switching state can be expressed as:

[0123] v(k)=uV dc

[0124] Where V dcdenoted as bus voltage, u represents the switching state, and u is selected from 1, 0, and -1.

[0125] Step S8: Obtain the predicted current value i at time k+1 obtained in step S7. pre (k+1) are respectively compared with the reference current value i of each phase at time k+1 obtained in step S6. ref (k+1) are compared;

[0126] Step S9: Predict the current value i at time k+1 pre The reference current values ​​i for each phase at time (k+1) and k+1. ref (k+1), construct the evaluation function, and select the predicted current value that minimizes the evaluation function value; refer to the flowchart of the predicted current algorithm. Figure 8 .

[0127] The evaluation function described in step S9 is as follows:

[0128] J(U k+1 )=(i ref (k+1)-i pre (k+1)) 2

[0129] In the formula, J(U k+1 ) represents the evaluation function.

[0130] Step S10: Send the switching signal corresponding to the selected predicted current value, i.e. the optimal switching state, to the three-phase unbalanced bridge converter.

[0131] Step S11: The three-phase unbalanced bridge converter controls the switched reluctance motor according to the received switching signal.

[0132] In summary, the overall process of the predictive current control method for a switched reluctance motor with a flux linkage designed in this invention is as follows: The stator current, rotor speed, and rotor position are measured using sensors; the stator flux linkage at time k is calculated; the three-phase flux linkage values ​​at time k are transformed to obtain the actual composite flux linkage; the sector is determined; the amplitude difference between the reference composite flux linkage and the actual composite flux linkage is calculated, and hysteresis control is performed; the hysteresis signal is used to determine whether the flux linkage needs to be increased or decreased; two candidate voltage vectors are selected based on the sector; the target torque value obtained through PI control is then processed by a torque distribution function. The reference torque value of each phase at time k+1 is obtained; the reference torque value of each phase at time k+1 is input into the current-torque-angle table i(T, θ) to obtain the reference current value of each phase at time k+1; the candidate voltage vector is substituted into the prediction model to predict the current at time k+1; the predicted current value at time k+1 is compared with the reference current value obtained through the torque-current inverse model; the voltage vector that minimizes the evaluation function is selected through the evaluation function; the switching signal corresponding to the selected optimal voltage vector is sent to the three-phase unbalanced bridge converter; and the switched reluctance motor is controlled.

[0133] The algorithm for predicting current used in this invention proceeds as follows: At the beginning of a control cycle, the sensor first samples the data, and the controller determines which sector the actual synthetic flux linkage is distributed in. Combining this with the flux linkage hysteresis signal, two control vectors are selected for traversal. Then, the controller uses the motor model, state equations, and various sampled parameters to predict the current after using these two control vectors. The predicted current is then substituted into an evaluation function to compare which of the two predicted currents is closer to the given value. The corresponding switching state of that vector is then input into the power converter to control the switched reluctance motor.

[0134] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A predictive current control method for a switched reluctance motor model with a magnetic flux linkage, characterized in that, Perform the following steps S1-S11 to complete the control of the switched reluctance motor: Step S1: Collect data on the switched reluctance motor. k The data at any given moment includes stator voltage, current, rotor speed, and rotor position angle; Step S2: Based on the collected data of the switched reluctance motor... k Data at time points is used to build a magnetic flux linkage model and obtain... k The three-phase flux linkage values ​​at time; Step S3: Refer to the direct torque control sector determination method, through... k The three-phase flux linkage values ​​at each moment are transformed to determine the sector in which they are located. According to the vector selection method of direct torque control, each sector has four candidate vectors: the vector that increases flux linkage when torque increases, the vector that decreases flux linkage when torque increases, the vector that increases flux linkage when torque decreases, and the vector that decreases flux linkage when torque decreases. Step S4: Divide the four candidate vectors of the sector obtained in step S3 into two categories: one category is vectors that increase the flux linkage, with two candidate vectors; the other category is vectors that decrease the flux linkage, with two candidate vectors. Based on the flux linkage hysteresis signal, determine whether the flux linkage needs to be increased or decreased, select the corresponding two candidate vectors, and use the two voltage vectors corresponding to the candidate vectors as the vectors to be traversed. Step S5: The target torque value obtained through PI control T e,ref The reference torque value for each phase at time k+1 is obtained using the torque distribution function. T ref ( k+ 1); The torque distribution function is as follows: in For rotor position angle, θ on To open the angle, θ off For the shut-off angle, θ ov The angle of overlap. t r =2π / N r For 12 / 8 phase switched reluctance motors, t r =π / 4; Step S6: Obtain the correspondence between torque, stator current, and rotor position angle through finite element simulation, and plot it as a torque-current-angle table. T ( i θ The torque value is obtained by looking up a table using the values ​​of stator current and rotor position angle; according to k Reference torque value of each phase at time +1 T ref ( k+ 1) k Each phase angle at time +1 θ ( k+ 1), and through the torque-current-angle table T ( i θ The current-torque-angle table obtained using the reverse lookup table algorithm i ( T θ ),get k Reference current values ​​of each phase at time +1 i ref ( k +1); Step S7: Construct a prediction model to predict the corresponding voltage vector after using a certain voltage vector. k The predicted current at time +1 is obtained by inputting the two voltage vectors selected in step S4 into the prediction model to obtain the corresponding voltage vectors. k Predicted current value at time +1 i pre ( k +1); The specific method for step S7 is as follows: The phase voltage equation of the switched reluctance motor is expressed as: in v The voltage across the phase winding is... i This refers to the stator winding current of this phase. R For phase winding resistance, For phase magnetic flux; Meanwhile, the flux linkage is a function related to the stator current and the rotor position angle. Taking the partial derivative of the above equation for the flux linkage, we get the following equation, which can be expressed as: Using the first-order forward difference to pair the above equation di / dt Approximate discretization is performed, and it is expressed as: in i ( k +1) is k Stator current at time +1; k The predicted current at time +1 is as follows: in, , v ( k ) is represented as: in V dc Bus voltage u In switch state. u Choose from 1, 0, -1; Step S8: Obtain the results from step S7 k Predicted current value at time +1 i pre ( k +1) respectively with the results obtained in step S6 k Reference current values ​​of each phase at time +1 i ref ( k +1) for comparison; Step S9: Targeting k Predicted current value at time +1 i pre ( k +1) and k Reference current values ​​of each phase at time +1 i ref ( k +1), construct the evaluation function, and select the predicted current value that minimizes the evaluation function value; Step S10: Send the switching signal corresponding to the selected predicted current value, i.e. the optimal switching state, to the three-phase unbalanced bridge converter. Step S11: The three-phase unbalanced bridge converter controls the switched reluctance motor according to the received switching signal.

2. The predictive current control method for a switched reluctance motor model with a magnetic flux linkage according to claim 1, characterized in that, The magnetic flux linkage model described in step S2 is as follows: in for k Magnetic linkage of time, i ( k )for k Stator current at time t, for k The rotor's position angle at any given moment. L q It is an inductor in a misaligned position. L dsat It is the current at the alignment position. i m The corresponding inductance value, i m It is the maximum current in the stator winding, and A and B in the formula are expressed as follows: It can be expressed as the following formula: in L d Stator current i Less than saturation phase current i s Inductance at that time, ψ m yes i = i m magnetic flux at time, N r It is the number of rotor poles.

3. The predictive current control method for a switched reluctance motor model with a magnetic flux linkage according to claim 1, characterized in that, The flux linkage transformation method described in step S3 is as follows: in , ， It is a three-phase magnetic flux. To synthesize magnetic flux.

4. The predictive current control method for a switched reluctance motor model with a magnetic flux linkage according to claim 1, characterized in that, The method for determining whether the flux linkage needs to be increased or decreased in step S4 is as follows: By comparing the given flux linkage with the synthesized flux linkage through the flux linkage hysteresis signal, if the given flux linkage is greater than the synthesized flux linkage, it means that the flux linkage needs to be increased; if the given flux linkage is less than the synthesized flux linkage, it means that the flux linkage needs to be decreased.

5. The predictive current control method for a switched reluctance motor model with a magnetic flux linkage according to claim 1, characterized in that, The evaluation function described in step S9 is as follows: In the formula, This represents the evaluation function.

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