Robust Predictive Control Method for Brushless Doubly-Fed Motor and Related Equipment

Abstract

The present application provides a robust predictive control method and related equipment for a brushless doubly-fed motor; the method includes: determining a relationship function between the control-side current of the motor and the power-side magnetic flux, control-side magnetic flux, and rotor magnetic flux of the motor according to the mathematical model of the motor, determining the differential of the control-side current with respect to time based on the relationship function, constructing a state-space equation of an extended state observer according to the obtained differential result, and determining the closed-loop transfer function of the state-space equation, obtaining a closed-loop characteristic equation according to the closed-loop transfer function, and setting the extended state observer according to the closed-loop characteristic equation; adding a one-beat delay compensation to the extended state observer, and determining the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer, determining a control-side voltage reference value according to the total disturbance prediction value and the control-side current prediction value, and using the control-side voltage reference value to convert it into a drive signal to control the brushless doubly-fed motor within a control period.

Description

Technical Field

[0001] Embodiments of the present application relate to the technical field of brushless doubly-fed motor control, and in particular, to a robust predictive control method for a brushless doubly-fed motor and related devices. Background Art

[0002] In the related control technology of brushless doubly-fed motors, when the parameters of the brushless doubly-fed motor change or are inaccurate, the parameter robustness of the deadbeat predictive control algorithm is poor, and power deadbeat tracking cannot be achieved even when the parameter changes are large.

[0003] Based on this, there is a need for a solution that can overcome the dependence on motor parameters, or a solution that can overcome the influence caused by large changes in motor parameters. Summary of the Invention

[0004] In view of this, the purpose of the present application is to propose a robust predictive control method for a brushless doubly-fed motor and related devices.

[0005] Based on the above purpose, the present application provides a robust predictive control method for a brushless doubly-fed motor, which is applied to a circuit structure with a motor, and the motor includes a brushless doubly-fed motor; the method includes:

[0006] In each control period of the circuit structure, perform the following operations:

[0007] According to the mathematical model of the motor, determine the relationship function between the control-side current of the motor and three magnetic fluxes, namely, the power-side magnetic flux, the control-side magnetic flux, and the rotor magnetic flux of the motor. Based on the relationship function, determine the differential of the control-side current with respect to time. According to the obtained differential result, construct the state-space equation of the extended state observer, and based on the state-space equation, determine the closed-loop transfer function. According to the closed-loop transfer function, obtain the closed-loop characteristic equation, and set the extended state observer according to the closed-loop characteristic equation.

[0008] Add a one-beat delay compensation to the extended state observer, and determine the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer. Determine the control-side voltage reference value according to the total disturbance prediction value and the control-side current prediction value, and use the control-side voltage reference value to convert it into a drive signal to control the brushless doubly-fed motor within the control period.

[0009] Further, before determining the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer, it further includes:

[0010] Based on the mathematical model of the motor, using the preset power-side flux reference value during the synchronization process of the motor, determine the first control-side current reference value, and design a flux outer-loop proportional-integral controller according to the first control-side current reference value;

[0011] Using the preset power-side power reference value during the power generation process of the motor, determine the second control-side current reference value, and design a power outer-loop proportional-integral controller according to the second control-side current reference value;

[0012] The flux outer-loop proportional-integral controller and the power outer-loop proportional-integral controller provide the first control-side current reference value and the second control-side current reference value for the circuit structure, and make the control-side current approach the first control-side current reference value during the synchronization process and approach the second control-side current reference value during the power generation process.

[0013] Furthermore, determine the relationship function between the control-side current of the motor and three fluxes, namely the power-side flux, the control-side flux, and the rotor flux, including:

[0014] Determine the mathematical model as the following relational expression,

[0015]

[0016] where, u1 represents the power-side voltage, u2 represents the control-side voltage, ψ1 represents the power-side flux vector, ψ2 represents the control-side flux vector, ψ r represents the rotor flux vector, i1 represents the power-side current, i2 represents the control-side current, i r represents the rotor current, L1 represents the power-side inductance, L2 represents the control-side inductance, L r represents the rotor inductance, R1 represents the power-side resistance, R2 represents the control-side resistance, R r represents the rotor resistance, p1 represents the power-side pole pair number, p2 represents the control-side pole pair number, ω g represents the grid voltage angular velocity of the circuit structure, L m1 represents the mutual inductance between the power side and the rotor, L m2 represents the mutual inductance between the control side and the rotor, ω m [[ID=3४]]represents the mechanical angular velocity of the rotor, j represents the imaginary part in the expression; use the motor mathematical model to determine the relationship function of the control-side current as shown below:

[0017]

[0018] where,

[0019] Furthermore, the differential of the control-side current with respect to time is determined based on the relationship function, and a state space equation of an extended state observer is constructed according to the obtained differential result, including:

[0020] By combining the mathematical model with the relationship function, the first differential formula of the control side current with respect to time is determined as follows:

[0021]

[0022] Where K1 = -λL m1 L m2 , K r =λL1L m2 ;

[0023] By combining the various disturbances in the circuit structure into a total disturbance, the first differential formula is rewritten to obtain the second differential formula shown below:

[0024]

[0025] Where F represents the total disturbance;

[0026] Based on the second differential formula, in the discrete domain, the extended state observer is constructed as the state space equation shown below:

[0027]

[0028] Among them, T sc represents the time interval of the control cycle, the lowercase letter k in the superscript represents the current control cycle, k+1 represents the next control cycle, β1 and β2 represent the first parameter and the second parameter of the extended state observer respectively, represents the error between the observed and predicted values of the control side current in the kth cycle, represents the control side current observed in the kth cycle, represents the control side current observed in the k+1th cycle, represents the total disturbance observed in the kth control cycle, represents the total disturbance observed in the k+1th control period.

[0029] Furthermore, a closed-loop characteristic equation is obtained according to the closed-loop transfer function, and an extended state observer is set according to the closed-loop characteristic equation, including:

[0030] The closed-loop transfer function is defined as:

[0031] Among them G c (z) represents the closed-loop transfer function, and z represents the z domain;

[0032] According to the closed-loop transfer function, the closed-loop characteristic equation shown below is determined:

[0033]

[0034] Wherein D(z) represents the closed-loop characteristic equation;

[0035] According to the closed-loop characteristic equation, the first parameter and the second parameter are respectively expressed as parameter formulas as shown below:

[0036]

[0037] Where β is a common pole and serves as the observation parameter of the extended state observer;

[0038] The extended state observer is set by setting the observation parameters.

[0039] Furthermore, determining the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer includes:

[0040] The one-beat delay compensation is added to the extended state observer, and the first prediction formula and the second prediction formula as shown below are obtained according to the predicted total disturbance prediction value and the control-side current prediction value:

[0041]

[0042]

[0043] in, represents the control side current reference value in the dq coordinate system, represents the predicted control side current value of the k+1th control cycle, represents the control side voltage of the kth control cycle obtained by sampling, Indicates the control side voltage required for the k+1th control cycle.

[0044] Furthermore, determining the control-side voltage reference value according to the total disturbance prediction value and the control-side current prediction value includes:

[0045] By combining the first prediction formula and the second prediction formula, a control side voltage reference value formula in a preset dq coordinate system is determined as follows:

[0046]

[0047] in, represents the control side voltage reference value;

[0048] Calculate the control-side voltage reference value according to the control-side voltage reference value formula.

[0049] Based on the same inventive concept, the present application further provides a robust predictive control device for a brushless doubly-fed motor based on an extended state observer, including: an extended state observer setting module and a control module;

[0050] Among them, the extended state observer setting module is configured to determine the relationship function between the control-side current of the motor and the three magnetic fluxes of the power-side magnetic flux, control-side magnetic flux and rotor magnetic flux of the motor according to the mathematical model of the motor, and determine the time derivative of the control-side current based on the relationship function. An extended state observer state space equation is constructed based on the obtained derivative result, and a closed-loop transfer function is determined based on the state space equation. A closed-loop characteristic equation is obtained according to the closed-loop transfer function, and the extended state observer is set according to the closed-loop characteristic equation;

[0051] The control module is configured to add a one-beat delay compensation to the extended state observer, and determine the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer. A control-side voltage reference value is determined according to the total disturbance prediction value and the control-side current prediction value, and the brushless doubly-fed motor is controlled within the control period by converting the control-side voltage reference value into a drive signal.

[0052] Based on the same inventive concept, the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the robust predictive control method of the brushless doubly-fed motor as described in any one of the above.

[0053] Based on the same inventive concept, the present application further provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions for causing the computer to execute the robust predictive control method of the brushless doubly-fed motor as described above.

[0054] As can be seen from the above, the robust predictive control method and related devices for the brushless doubly-fed motor provided by the present application, based on the construction and setting of the extended state observer, comprehensively consider the relationship between the control-side current and the magnetic flux, and determine the state space equation, closed-loop transfer function and closed-loop characteristic equation of the ESO through differentiation for construction and setting, to predict the total disturbance and the control-side current, and through the designed total disturbance and the designed linear error function, to achieve effective prediction and tracking when the parameters change or are inaccurate, improve the robustness of the parameters, overcome the defect of poor parameter robustness, and improve the effect of deadbeat prediction. Description of the Drawings

[0055] To more clearly illustrate the technical solutions in the present application or related technologies, the following will briefly introduce the drawings required for use in the embodiments or the description of related technologies. Obviously, the drawings in the following description are only the embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0056] Figure 1 It is a flowchart of the robust predictive control method for a brushless doubly-fed motor according to an embodiment of the present application;

[0057] Figure 2 It is a circuit structure diagram according to an embodiment of the present application;

[0058] Figure 3 It is a structural diagram of the robust predictive control principle of an extended state observer according to an embodiment of the present application;

[0059] Figure 4 It is a structural diagram of an extended state observer in the discrete domain according to an embodiment of the present application;

[0060] Figure 5 It is a schematic structural diagram of a robust predictive control device for a brushless doubly-fed motor according to an embodiment of the present application;

[0061] Figure 6 It is a schematic structural diagram of an electronic device according to an embodiment of the present application. Detailed implementation manners

[0062] To make the purpose, technical solutions, and advantages of the present application clearer and more understandable, the following further details the present application in combination with specific embodiments and referring to the drawings.

[0063] It should be noted that unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should have the ordinary meaning understood by those of ordinary skill in the field to which the present application belongs. The "first", "second", and similar terms used in the embodiments of the present application do not represent any order, quantity, or importance, but are only used to distinguish different components. Words such as "including" or "comprising" mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right", etc. are only used to represent relative positional relationships, and when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0064] As described in the background art section, the related brushless doubly-fed motor control methods are still difficult to meet the needs in actual production.

[0065] In the process of implementing this application, the applicant found that the main problems existing in the related brushless doubly-fed motor control methods are as follows: when the parameters of the brushless doubly-fed motor change or are inaccurate, the parameter robustness of the control algorithm is poor, and when the parameters change greatly, power error-free tracking cannot even be achieved.

[0066] For example, for the deadbeat predictive control algorithm, the formula derivation itself uses the complete motor mathematical model and is easily affected by parameter mismatches.

[0067] Furthermore, the applicant also found during the research that when the actual motor parameters change or the motor parameters in the controller do not match the actual values, the dynamic performance exhibited by the motor will be affected.

[0068] It can be seen that the deadbeat predictive control method in other technologies has defects such as poor parameter robustness and difficulty in achieving power error-free tracking due to its excessive dependence on motor parameters.

[0069] Based on this, one or more embodiments in this application provide a robust predictive control method for a brushless doubly-fed motor.

[0070] The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0071] In the embodiments of this application, taking Figure 2 the shown circuit structure as a specific example, it includes a three-phase power supply voltage V dc , a brushless doubly-fed motor, a three-phase two-level inverter, a DC-side capacitor, a voltage and current sampling circuit, a dSPACE (real-time simulation system), and a driving circuit.

[0072] The voltage and current sampling circuit uses voltage Hall sensors and current Hall sensors to respectively collect the DC-side voltage, the a, b, c-phase voltages on the power side, the a, b, c-phase voltages on the control side, and the a, b-phase currents on the power side and the a, b-phase currents on the control side. The sampling signals enter the dSPACE through the signal conditioning circuit and are converted into digital signals; among them, as a specific example for implementing the method proposed in this application, the dSPACE can output six-way switching pulses, and then obtain the final driving signals of the six switching tubes of the inverter through the driving circuit.

[0073] Referring to Figure 1 , a robust predictive control method for a brushless doubly-fed motor according to an embodiment of this application is applied to a circuit structure with a motor, and the motor includes a brushless doubly-fed motor. The method includes the following steps:

[0074] Step S101: In each control cycle of the circuit structure, perform the following operations:

[0075] According to the mathematical model of the motor, a relationship function between the control-side current of the motor and the three fluxes of the motor, namely the power-side flux, the control-side flux and the rotor flux, is determined; based on the relationship function, the differential of the control-side current with respect to time is determined; based on the obtained differential result, a state-space equation of an extended state observer is constructed; and based on the state-space equation, a closed-loop transfer function is determined; based on the closed-loop transfer function, a closed-loop characteristic equation is obtained; and based on the closed-loop characteristic equation, an extended state observer is set.

[0076] In the embodiment of the present application, based on the above circuit structure, the mathematical model of the brushless doubly-fed motor can be determined first, and the ESO (Extended State Observer) can be set according to the mathematical model.

[0077] In this embodiment, a brushless doubly-fed motor and dSPACE are used as a specific example for implementing this embodiment.

[0078] Specifically, first, the magnetic flux relationship in the rotating dq coordinate system shown below is used as the mathematical model of the brushless doubly fed motor:

[0079]

[0080] Combine Figure 3 In the above mathematical model, u1 represents the power side voltage, u2 represents the control side voltage, ψ1 represents the power side flux vector, ψ2 represents the control side flux vector, ψ r represents the rotor flux vector, i1 represents the power side current, i2 represents the control side current, i r Indicates the rotor current, L1 indicates the power side inductance, L2 indicates the control side inductance, L r Indicates rotor inductance, R1 indicates power side resistance, R2 indicates control side resistance, R r represents the rotor resistance, p1 represents the number of pole pairs on the power side, p2 represents the number of pole pairs on the control side, ω g represents the grid voltage angular velocity of the circuit structure, L m1 Indicates the mutual inductance between the power side and the rotor, L m2 represents the mutual inductance between the control side and the rotor, ω m represents the mechanical angular velocity of the rotor, j represents the imaginary part in the expression, where Figure 3 The power source of the overall circuit structure in the principle structure diagram shown is the power grid shown in the diagram.

[0081] It can be seen that the mathematical model adopts a rotating dq coordinate system, and the coordinate rotation speed is equal to the grid voltage angular velocity ω g .

[0082] Furthermore, based on the above mathematical model, the relationship between the current on the control side and three magnetic fluxes, namely the magnetic flux on the power side, the magnetic flux on the control side, and the rotor magnetic flux, can be obtained and expressed as the following relationship function:

[0083]

[0084] Among them, in this relationship function,

[0085] Furthermore, the relationship function can be combined with the above mathematical model to obtain the differential of the current on the control side with respect to time, and this differential is expressed as the following first differential formula:

[0086]

[0087] where K1 = -λL m1 L m2 , K r = λL1L m2 .

[0088] It can be seen that the first differential formula can contain multiple disturbances, such as uncertain coefficient variables and external disturbances, etc. Therefore, these multiple disturbances can be synthesized into a total disturbance, and this total disturbance is fed back to the driven circuit to be controlled, so as to be able to observe both the non-linear part and the unknown external disturbances, and improve the parameter robustness of this method.

[0089] Specifically, by synthesizing multiple disturbances into a total disturbance, the above first differential formula can be expressed as the following second differential formula:

[0090]

[0091] where F represents the synthesized total disturbance and serves as the predicted value of the total disturbance.

[0092] It can be seen that in the above second differential formula, in the total disturbance represented by F, disturbances caused by factors such as parameter mismatch or parameter change can be captured and observed in real time by the ESO, so as to achieve compensation during the control process.

[0093] In this embodiment, based on the above basis, a linear ESO can be used to replace the non-linear error function with a linear error function to simplify the design and reduce the computational redundancy in the design of the ESO.

[0094] Specifically, according to the second differential formula above, it can be seen that when the ESO is considered to be a first-order single-input single-output, the state space equation shown below can be designed for the ESO in the discrete domain:

[0095]

[0096] Among them, T sc represents the time interval of the control cycle, the lowercase letter k in the superscript represents the current control cycle, k+1 represents the next control cycle, β1 and β2 represent the first parameter and the second parameter of the extended state observer respectively, represents the error between the observed and predicted values of the control side current in the kth cycle, represents the control side current observed in the kth cycle, represents the control side current observed in the k+1th cycle, represents the total disturbance observed in the kth control cycle, represents the total disturbance observed in the k+1th control period.

[0097] In this embodiment, the control period may be regarded as a period of the sampling time. In some other embodiments, the control period may not correspond to the period of the sampling time, which is not specifically limited here.

[0098] Furthermore, based on the state-space equation determined above, an ESO applicable to the brushless doubly-fed motor in this embodiment can be preliminarily constructed, and the preliminarily constructed ESO can be further configured.

[0099] Specifically, if Figure 2 and Figure 3 As shown, the sampled control side current can be used as input, the predicted control side current can be used as output, and the control side voltage can be used as the disturbance term. Based on this, we can get Figure 4 Figure 2 shows the structure of the ESO.

[0100] Further, according to Figure 4 As shown, the ESO closed-loop transfer function of the brushless doubly fed motor can be designed as the following formula in the z domain:

[0101]

[0102] Among them G c (z) represents the closed-loop transfer function, and z represents the z domain.

[0103] Furthermore, based on the above closed-loop transfer function, the closed-loop characteristic equation of the ESO can be determined as follows:

[0104]

[0105] where \(D(z)\) represents the closed-loop characteristic equation.

[0106] It can be seen that when all the characteristic roots of the discrete ESO are distributed on the unit circle in the z-domain, the ESO is stable. After tuning the parameters, the poles of the above-mentioned closed-loop characteristic equation can be placed at the same point. Therefore, the first parameter and the second parameter of the above-mentioned ESO can be expressed as the following parameter formulas:

[0107]

[0108] where \(\beta\) is the observation parameter of the extended ESO and serves as a common pole, satisfying \(0 < \beta < 1\).

[0109] It can be seen that \(\beta\) is the only parameter that needs to be tuned for the extended state observer. Selecting different values of \(\beta\) will also affect its control performance. Specifically, the larger \(\beta\) is, the stronger the anti-disturbance ability of the extended state observer is, and the smaller \(\beta\) is, the better the tracking performance of the extended state observer is. For example, in this embodiment, taking \(\beta = 0.52\) as a specific example.

[0110] It can be seen that based on the determined observation parameters, as well as the first parameter and the second parameter, the preliminarily constructed ESO can be set, and the characteristics of the non-linear error function can be reflected.

[0111] Step S102: In each control period of the circuit structure, perform the following operations:

[0112] Add one-beat delay compensation to the extended state observer, and determine the total disturbance prediction value and the predicted control-side current value predicted by the extended state observer. Determine the control-side voltage reference value according to the total disturbance prediction value and the predicted control-side current value, and use the control-side voltage reference value to convert it into a drive signal to control the brushless doubly-fed motor within the control period.

[0113] In the embodiment of the present application, based on the above-set ESO, the predicted value of the control-side current can be determined.

[0114] Specifically, after considering one-beat delay compensation, the prediction of the control-side current by the ESO can be expressed as the following first prediction formula and second prediction formula:

[0115]

[0116]

[0117] where represents the control-side current reference value in the dq coordinate system, represents the predicted value of the control-side current in the (k + 1)-th control period. represents the sampled control-side voltage in the k-th control period. represents the required control-side voltage in the (k + 1)-th control period.

[0118] Furthermore, based on the above first prediction formula and second prediction formula, the reference value of the control-side voltage in the synchronous dq coordinate system can be determined.

[0119] Specifically, by combining the above first prediction formula and second prediction formula, the following reference value formula of the control-side voltage can be obtained:

[0120]

[0121] where represents the reference value of the control-side voltage.

[0122] In this embodiment represents the control-side voltage in the k-th control period, and at the same time, it can also be regarded as the reference value of the control-side voltage calculated in the previous control period.

[0123] Furthermore, the reference value of the control-side voltage can be stored for relevant calculations in the current control period.

[0124] In this embodiment, based on the above execution process, the coordinate transformation of the control-side voltage needs to be back to the control winding coordinate system, and the control-side voltage is converted into a switching signal through the relevant SVM (Space Vector Modulation) module in Figure 3 and further the switching signal acts on the inverter or other relevant devices.

[0125] In some other embodiments, during the construction, setting and prediction process of the above ESO, before the ESO predicts the total disturbance prediction value and the control-side current prediction value, or before the above step S101, a PI (Proportional-Integral) control mechanism can also be added to determine the reference value of the control-side current.

[0126] Specifically, it may include:

[0127] Step S103: Based on the mathematical model of the motor, using the reference value of the power-side magnetic flux preset during the synchronization process of the motor, determine the first reference value of the control-side current, and design a magnetic flux outer-loop proportional-integral controller according to the first reference value of the control-side current;

[0128] Determine the second control-side current reference value by using the power-side power reference value preset during the power generation process of the motor, and design a power outer-loop proportional-integral controller according to the second control-side current reference value;

[0129] The flux outer-loop proportional-integral controller and the power outer-loop proportional-integral controller provide the first control-side current reference value and the second control-side current reference value for the circuit structure, and make the control-side current approach the first control-side current reference value during the synchronization process and approach the second control-side current reference value during the power generation process.

[0130] In this step, based on the brushless doubly-fed motor in the foregoing embodiment and based on the same mathematical model in the foregoing embodiment, for the brushless doubly-fed motor, it is necessary to design a flux outer-loop for its synchronization process and a power outer-loop for its power generation process.

[0131] Specifically, first, for the synchronization process of the brushless doubly-fed motor, at the start of its synchronization, the power motor is disconnected from the power grid, which is equivalent to an open circuit on the power side, so the current on the power side is 0, and an induced voltage can be generated on the power side.

[0132] Furthermore, the induced voltage can be made to track the grid voltage by adjusting the control-side current.

[0133] Furthermore, when the amplitude and phase of the induced voltage are equal to those of the grid voltage, the power-side circuit breaker can be closed and the power grid can be connected to the power motor to complete the synchronization process.

[0134] It can be seen that during the synchronization process, the power side does not generate power, and the induced voltage is only related to the power-side flux.

[0135] Specifically, under steady-state conditions, the relationship between the power-side flux reference value and the control-side current reference value can be obtained from the mathematical model of the brushless doubly-fed motor in the foregoing embodiment as shown below:

[0136]

[0137] Among them, represents the power-side flux reference value, and in this embodiment, Figure 3 the virtual flux ψ of the power grid in v can be used to represent: ψ v =-ju g / ω g .

[0138] In this embodiment, with the grid voltage as the d-axis for orientation, the above formula is transformed into the synchronous dq-axis coordinate system, that is: Specifically, u 1d =|u gBased on this, during the synchronization process, the reference value of the current on the control side in the synchronized dq coordinate system can be obtained. That is, the first reference value of the control-side current.

[0139] Furthermore, after the synchronization process ends, the power motor is directly connected to the power grid, and the brushless doubly-fed motor enters the power generation process. Among them, the voltage drop across the power-side resistor can be neglected compared to the power grid voltage.

[0140] It can be seen that at this time, R1i1≈0, and the power flux linkage ψ1 is only related to the power grid voltage. Under an ideal power grid, the power grid voltage is constant, and ψ1 can be considered as a known constant.

[0141] Furthermore, in the synchronized coordinate system with the power grid voltage orientation, the power flux linkage on the d-axis is specifically: ψ 1d =0 and ψ 1q =-|u g | / ω g .

[0142] Furthermore, the power on the power side of the brushless doubly-fed motor can be expressed by the following formula:

[0143]

[0144] In summary, the active and reactive powers on the power side during the power generation process are obtained:

[0145]

[0146] Among them, P1 represents the active power, and Q1 represents the reactive power.

[0147] It can be seen that in the case of voltage orientation, the d-axis controls the active power, and the q-axis controls the reactive power.

[0148] Furthermore, similar to the synchronization process, under the steady-state conditions of the power generation process, according to the mathematical model of the brushless doubly-fed motor, the dynamic relationship between the power-side current i1 and the control-side current i2 can be obtained and expressed by the following formula:

[0149]

[0150] Furthermore, still taking the power grid voltage as the d-axis for orientation, that is: u 1d =|u g |, the above formula can be transformed into the synchronized dq-axis coordinate system to obtain the reference value of the control-side current in the synchronized dq coordinate system during the power generation process and used as the second reference value of the control-side current.

[0151] In this embodiment, both the first control-side current reference value during the synchronization process and the second control-side current reference value during the power generation process are used as the control-side current reference value. For the sake of convenient description, they are all represented by the same symbols as above and are distinguished by the way of limiting during the specific description.

[0152] In this embodiment, a PI controller can be constructed, and the reference value of the control-side current in the dq coordinate system obtained above is used to determine the proportional parameter K p and the integral coefficient K i of the PI controller.

[0153] Specifically, for the synchronization process, the first control-side current reference value can be expressed by the following formula:

[0154]

[0155] where K p represents the proportional coefficient of the PI controller, and K i represents the integral coefficient of the PI controller; ψ vd is the virtual flux linkage of the d-axis converted to the synchronous dq-axis coordinate system, and ψ vq s the virtual flux linkage of the q-axis converted to the synchronous dq-axis coordinate system; ψ 1d is the power-side flux linkage of the d-axis converted to the synchronous dq-axis coordinate system, and ψ 1q is the power-side flux linkage of the q-axis converted to the synchronous dq-axis coordinate system.

[0156] Furthermore, for the power generation process, the second control-side current reference value can be expressed by the following formula:

[0157]

[0158] where K p represents the proportional coefficient of the PI controller, and K i represents the integral coefficient of the PI controller; P1 ref represents the active power reference value of the power side, represents the active and reactive power reference values of the power side; P1 k represents the instantaneous active power of the power side in the k-th cycle obtained, represents the instantaneous reactive power of the power side in the k-th cycle obtained.

[0159] It can be seen that based on the proportional coefficient and integral coefficient of the PI controller determined above for the synchronization process and the power generation process, Figure 3Set the PI controller therein, and determine the current reference value on the control side in each process, so as to provide the current reference value on the control side to step S101 and step S102.

[0160] It can be seen that the robust predictive control method of the brushless doubly-fed motor according to the embodiment of the present application, based on the construction and setting of the extended state observer, comprehensively considers the relationship between the current on the control side and the magnetic flux, and constructs and sets the state space equation and closed-loop transfer function of the ESO by differentiation to predict the total disturbance and the current on the control side, and realizes effective prediction and tracking when the parameters change or are inaccurate through the designed total disturbance and the designed linear error function, improves the robustness of the parameters, overcomes the defect of poor parameter robustness, and improves the effect of deadbeat prediction.

[0161] It should be noted that the method according to the embodiment of the present application can be executed by a single device, such as a computer or a server. The method of this embodiment can also be applied to a distributed scenario and completed by multiple devices cooperating with each other. In this case of a distributed scenario, one of the multiple devices can only execute one or more steps of the method according to the embodiment of the present application, and these multiple devices will interact with each other to complete the described method.

[0162] It should be noted that some embodiments of the present application have been described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the above embodiments and still achieve the desired result. Additionally, the processes depicted in the drawings do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0163] Based on the same inventive concept, corresponding to the method according to any of the above embodiments, the embodiment of the present application further provides a robust predictive control device for a brushless doubly-fed motor.

[0164] Referring to Figure 5 , the robust predictive control device for the brushless doubly-fed motor includes: an extended state observer setting module 501 and a control module 502;

[0165] Among them, the extended state observer setting module 501 is configured to determine the relationship function between the control-side current of the motor and three magnetic fluxes, namely, the power-side magnetic flux, the control-side magnetic flux, and the rotor magnetic flux, according to the mathematical model of the motor. Based on the relationship function, the differential of the control-side current with respect to time is determined, and the state-space equation of the extended state observer is constructed according to the obtained differential result. Then, the closed-loop transfer function is determined based on the state-space equation, and the closed-loop characteristic equation is obtained according to the closed-loop transfer function. The extended state observer is set according to the closed-loop characteristic equation.

[0166] The control module 502 is configured to add a one-beat delay compensation to the extended state observer, and determine the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer. The control-side voltage reference value is determined according to the total disturbance prediction value and the control-side current prediction value, and the drive signal is converted by using the control-side voltage reference value to control the brushless doubly-fed motor within the control period.

[0167] In some other embodiments, the robust predictive control device of the brushless doubly-fed motor further includes a PI controller module.

[0168] The PI controller module 503 is configured to determine a first control-side current reference value based on the mathematical model of the motor by using the preset power-side magnetic flux reference value during the synchronization process of the motor, and design a magnetic flux outer-loop proportional-integral controller according to the first control-side current reference value.

[0169] A second control-side current reference value is determined by using the preset power-side power reference value during the power generation process of the motor, and a power outer-loop proportional-integral controller is designed according to the second control-side current reference value.

[0170] The magnetic flux outer-loop proportional-integral controller and the power outer-loop proportional-integral controller provide the first control-side current reference value and the second control-side current reference value for the circuit structure, and make the control-side current approach the first control-side current reference value during the synchronization process and approach the second control-side current reference value during the power generation process.

[0171] For the convenience of description, when describing the above device, it is divided into various modules according to functions for separate description. Of course, when implementing the embodiments of the present application, the functions of each module can be implemented in one or more software and / or hardware.

[0172] The device in the above embodiments is used to implement the corresponding robust predictive control method of the brushless doubly-fed motor in any of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0173] Based on the same inventive concept, corresponding to the method of any of the above embodiments, an embodiment of the present application further provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor. When the processor executes the program, it implements the robust predictive control method of the brushless doubly-fed motor described in any one of the above embodiments.

[0174] Figure 6 FIG. shows a more specific schematic diagram of the hardware structure of the electronic device provided in this embodiment. The device may include: a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. Among them, the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040 are communicatively connected to each other inside the device through the bus 1050.

[0175] The processor 1010 may be implemented in a general way such as a CPU (Central Processing Unit), a microprocessor, an application specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of the present application.

[0176] The memory 1020 may be implemented in forms such as a ROM (Read Only Memory), a RAM (Random Access Memory), a static storage device, a dynamic storage device, etc. The memory 1020 may store an operating system and other application programs. When implementing the technical solutions provided in the embodiments of the present application through software or firmware, the relevant program codes are stored in the memory 1020 and called and executed by the processor 1010.

[0177] The input / output interface 1030 is used to connect to an input / output module to implement information input and output. The input / output module may be configured as a component in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Among them, the input device may include a keyboard, a mouse, a touch screen, a microphone, various sensors, etc., and the output device may include a display, a speaker, a vibrator, an indicator light, etc.

[0178] The communication interface 1040 is used to connect to a communication module (not shown in the figure) to implement communication interaction between this device and other devices. Among them, the communication module may implement communication in a wired manner (such as USB, network cable, etc.) or in a wireless manner (such as mobile network, WIFI, Bluetooth, etc.).

[0179] The bus 1050 includes a path for transmitting information between various components of the device, such as the processor 1010, the memory 1020, the input / output interface 1030, and the communication interface 1040.

[0180] It should be noted that although only the processor 1010, the memory 1020, the input / output interface 1030, the communication interface 1040, and the bus 1050 are shown in the above device, in the specific implementation process, the device may further include other components necessary for normal operation. In addition, those skilled in the art can understand that the above device may also only include the components necessary to implement the solution of the embodiment of the present application, and does not necessarily include all the components shown in the figure.

[0181] The device of the above embodiment is used to implement the robust predictive control method of the brushless doubly-fed motor corresponding to any one of the foregoing embodiments, and has the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0182] Based on the same inventive concept, corresponding to the method of any of the above embodiments, the present application further provides a non-transitory computer-readable storage medium storing computer instructions for causing the computer to execute the robust predictive control method of the brushless doubly-fed motor as described in any of the above embodiments.

[0183] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. The information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device.

[0184] The computer instructions stored in the storage medium of the above embodiment are used to cause the computer to execute the robust predictive control method of the brushless doubly-fed motor as described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be elaborated here.

[0185] Those of ordinary skill in the art should understand that: The discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the present application (including the claims) is limited to these examples; Under the concept of the present application, the technical features in the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations in different aspects of the embodiments of the present application as described above. For the sake of brevity, they are not provided in detail.

[0186] In addition, for simplicity of explanation and discussion, and in order not to make the embodiments of the present application difficult to understand, the well-known power / ground connections to integrated circuit (IC) chips and other components may or may not be shown in the provided drawings. Further, the devices may be shown in block diagram form in order to avoid making the embodiments of the present application difficult to understand, and this also takes into account the fact that the details of the implementation of these block diagram devices are highly dependent on the platform on which the embodiments of the present application are to be implemented (i.e., these details should be entirely within the understanding of those skilled in the art). In cases where specific details (such as circuits) are set forth to describe exemplary embodiments of the present application, it will be apparent to those skilled in the art that the embodiments of the present application may be implemented without these specific details or with variations of these specific details. Therefore, these descriptions should be considered illustrative rather than restrictive.

[0187] Although the present application has been described in connection with specific embodiments of the present application, many alternatives, modifications, and variations of these embodiments will be apparent to those of ordinary skill in the art based on the foregoing description. For example, other memory architectures (such as dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0188] The embodiments of the present application are intended to cover all such alternatives, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application shall be included within the protection scope of the present application.

Claims

1. A robust predictive control method for a brushless doubly-fed motor, characterized in that: Applicable to a circuit structure having a motor, wherein the motor comprises a brushless doubly-fed motor; The method comprises: In each control cycle of the circuit structure, the following operations are performed: Determine, based on a mathematical model of the motor, a relationship function between a control-side current of the motor and three flux linkages: a power-side flux linkage, a control-side flux linkage, and a rotor flux linkage of the motor; The mathematical model is determined as the following relationship: Among them, u1 represents the power side voltage, u2 represents the control side voltage, ψ1 represents the power side flux vector, ψ2 represents the control side flux vector, ψ r represents the rotor flux vector, i1 represents the power side current, i2 represents the control side current, i r Indicates the rotor current, L1 indicates the power side inductance, L2 indicates the control side inductance, L r Indicates rotor inductance, R1 indicates power side resistance, R2 indicates control side resistance, R r represents the rotor resistance, p1 represents the number of pole pairs on the power side, p2 represents the number of pole pairs on the control side, ω g represents the grid voltage angular velocity of the circuit structure, L m1 Indicates the mutual inductance between the power side and the rotor, L m2 represents the mutual inductance between the control side and the rotor, ω m represents the mechanical angular velocity of the rotor, j represents the imaginary part in the expression; The relationship function of the control-side current is determined using the motor mathematical model as shown below: in, Determining the differential of the control-side current with respect to time based on the relationship function, constructing a state-space equation of an extended state observer according to the obtained differential result, determining a closed-loop transfer function based on the state-space equation, obtaining a closed-loop characteristic equation according to the closed-loop transfer function, and setting an extended state observer according to the closed-loop characteristic equation; One-beat delay compensation is added to the extended state observer, and a total disturbance prediction value and a predicted control-side current prediction value predicted by the extended state observer are determined. A control-side voltage reference value is determined based on the total disturbance prediction value and the control-side current prediction value, and the control-side voltage reference value is converted into a drive signal to control the brushless doubly-fed motor within the control period.

2. The method according to claim 1, characterized in that Before determining the total disturbance prediction value and the control-side current prediction value predicted by the extended state observer, the method further includes: Based on a mathematical model of the motor, a first control-side current reference value is determined using a power-side flux reference value preset during synchronization of the motor, and a flux outer-loop proportional-integral controller is designed according to the first control-side current reference value; Determine a second control-side current reference value by using a power-side power reference value preset during the power generation process of the motor, and design a power outer-loop proportional-integral controller according to the second control-side current reference value; The flux outer loop proportional-integral controller and the power outer loop proportional-integral controller provide the first control side current reference value and the second control side current reference value for the circuit structure, and make the control side current approach the first control side current reference value during the synchronization process and approach the second control side current reference value during the power generation process.

3. The method according to claim 1, characterized in that Determining the differential of the control-side current with respect to time based on the relationship function, and constructing a state space equation of an extended state observer according to the obtained differential result, includes: By combining the mathematical model with the relationship function, the first differential formula of the control-side current with respect to time is determined as follows: Where K1 = -λL m1 L m2 , K r =λL1L m2 ; By combining the various disturbances in the circuit structure into a total disturbance, the first differential formula is rewritten to obtain the second differential formula shown below: Where F represents the total disturbance; Based on the second differential formula, in the discrete domain, the extended state observer is constructed as the state space equation shown below: Among them, T sc represents the time interval of the control cycle, the lowercase letter k in the superscript represents the current control cycle, k+1 represents the next control cycle, β1 and β2 represent the first parameter and the second parameter of the extended state observer respectively, represents the error between the observed and predicted values of the control side current in the kth cycle, represents the control side current observed in the kth cycle, represents the control side current observed in the k+1th cycle, represents the total disturbance observed in the kth control cycle, represents the control side voltage of the kth control cycle obtained by sampling, represents the total disturbance observed in the k+1th control period.

4. The method according to claim 3, characterized in that The step of obtaining a closed-loop characteristic equation according to the closed-loop transfer function and setting an extended state observer according to the closed-loop characteristic equation comprises: The closed-loop transfer function is defined as: Among them G c (z) represents the closed-loop transfer function, z represents the z domain, β1 represents the first parameter, and β2 represents the second parameter; According to the closed-loop transfer function, the closed-loop characteristic equation shown below is determined: Wherein D(z) represents the closed-loop characteristic equation; According to the closed-loop characteristic equation, the first parameter and the second parameter are respectively expressed as parameter formulas as shown below: Where β is a common pole and serves as the observation parameter of the extended state observer; The extended state observer is set by setting the observation parameters.

5. The method according to claim 3, characterized in that The determining of the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer includes: The one-beat delay compensation is added to the extended state observer, and the first prediction formula and the second prediction formula as shown below are obtained according to the predicted total disturbance prediction value and the control-side current prediction value: in, represents the predicted control side current value of the k+1th control cycle, represents the control side voltage of the kth control cycle obtained by sampling, Indicates the control side voltage required for the k+1th control cycle.

6. The method according to claim 5, characterized in that The determining the control-side voltage reference value according to the total disturbance prediction value and the control-side current prediction value includes: By combining the first prediction formula and the second prediction formula, a control side voltage reference value formula in a preset dq coordinate system is determined as follows: in, represents the control side voltage reference value; The control side voltage reference value is calculated according to the control side voltage reference value formula.

7. A robust predictive control device for a brushless doubly-fed motor, characterized in that: include: Extended state observer setting module and control module; The extended state observer setting module is configured to perform the following operations in each control cycle: Determine, based on a mathematical model of the motor, a relationship function between a control-side current of the motor and three flux linkages: a power-side flux linkage, a control-side flux linkage, and a rotor flux linkage of the motor; The mathematical model is determined as the following relationship: Among them, u1 represents the power side voltage, u2 represents the control side voltage, ψ1 represents the power side flux vector, ψ2 represents the control side flux vector, ψ r represents the rotor flux vector, i1 represents the power side current, i2 represents the control side current, i r Indicates the rotor current, L1 indicates the power side inductance, L2 indicates the control side inductance, L r Indicates rotor inductance, R1 indicates power side resistance, R2 indicates control side resistance, R r represents the rotor resistance, p1 represents the number of pole pairs on the power side, p2 represents the number of pole pairs on the control side, ω g Indicates the grid voltage angular velocity, L m1 Indicates the mutual inductance between the power side and the rotor, L m2 represents the mutual inductance between the control side and the rotor, ω m represents the mechanical angular velocity of the rotor, j represents the imaginary part in the expression; The relationship function of the control-side current is determined using the motor mathematical model as shown below: in, Determining the differential of the control-side current with respect to time based on the relationship function, constructing a state-space equation of an extended state observer according to the obtained differential result, determining a closed-loop transfer function based on the state-space equation, obtaining a closed-loop characteristic equation according to the closed-loop transfer function, and setting an extended state observer according to the closed-loop characteristic equation; The control module is configured to add one-beat delay compensation to the extended state observer, determine the total disturbance prediction value and the predicted control-side current prediction value predicted by the extended state observer, determine the control-side voltage reference value based on the total disturbance prediction value and the control-side current prediction value, and use the control-side voltage reference value to convert it into a drive signal to control the brushless doubly-fed motor within the control period.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable by the processor, wherein: When the processor executes the computer program, the method according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium, characterized in that The non-transitory computer-readable storage medium stores computer instructions for causing a computer to execute the method according to any one of claims 1 to 6.

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