Sensorless control method and system for doubly-fed induction wind generators

Abstract

The application discloses a kind of for doubly-fed induction wind-driven generator's position sensorless control method and system, comprising: acquisition three-phase stator current value and rotor current value, obtain in stationary coordinate system under stator current vector and rotor current vector, two vectors are input phase-locked loop, obtain the included angle between stator current vector and rotor current vector;Remove grid voltage from closed loop control loop, only grid voltage is as feedforward item to the included angle and is feedforward compensation;Through net side PWM converter, maintain DC bus voltage stability;According to rotor speed, give active instruction;Through rotor side PWM converter, active instruction and reactive instruction are converted into the instruction of rotor current cross-axis component, to realize decoupling control.The application is mainly used for DFIG wind-driven generator or similar topology position sensorless control, without the position sensor structure of traditional encoder, rotating transformer etc., with better grid fault ride-through capability and robustness.

Description

Technical Field

[0001] The present application relates to the technical field of wind turbines, and in particular to a position sensorless control method and system for a doubly-fed induction wind turbine. Background Art

[0002] Compared to permanent magnet synchronous wind turbines, DFIG wind turbines offer the advantages of smaller converter capacity and lower costs. They are widely used in wind farms and already account for over 60% of wind power generation in my country. Accurate rotor position information is essential for the operation and control of DFIG wind turbines. However, the delicate mechanical structure of position sensors (such as encoders and resolvers) is susceptible to damage, making them a weak link in wind turbine systems.

[0003] In order to improve the stability of the DFIG wind power generation system, different position sensorless control strategies have been proposed, which can be mainly divided into the following three categories: the first category is the open-loop calculation method, which directly solves the rotor position angle through the mathematical and physical equations of the DFIG wind turbine; the second category is the model reference adaptive control strategy, which realizes the closed-loop rotor position observer through the PI controller by subtracting the adjustable model from the reference model; the third category is the high-frequency signal injection method, which injects a high-frequency signal on the rotor side or the stator side, receives the response signal generated by electromagnetic induction on the other side, and uses the electromagnetic coupling characteristics of the DFIG to solve the rotor position angle.

[0004] While there has been some academic research on sensorless DFIG technology, there are no reports of its use in mass-produced products. This is primarily due to the fact that existing DFIG rotor position estimation methods are typically only applicable under normal grid conditions. However, once the grid voltage experiences a voltage drop or surge, the motor's stator voltage and current will be directly and dramatically affected, leading to rotor position estimation errors and, consequently, fault ride-through failure. Research has found that the open-loop method relies heavily on motor parameters, and the lack of a closed-loop feedback mechanism results in large position estimation errors during transients, making it difficult to meet low-voltage ride-through requirements. While the high-frequency signal injection method is insensitive to motor parameters and can achieve position observation during voltage drops, it severely impacts power generation quality, making it difficult to apply in practice. The reference model of the model reference adaptive method is significantly disturbed during transients with drastic changes in electrical quantities, making it impossible to effectively observe rotor position during faults.

[0005] In summary, the existing DFIG position sensorless control strategy is difficult to achieve effective observation of the rotor position under the condition of grid fault, and it is difficult to achieve the grid's fault ride-through capability indicators. Summary of the Invention

[0006] In response to the deficiencies of the above-mentioned background technology, the embodiments of the present application provide a position sensorless control method and system for a doubly-fed induction wind turbine to solve the technical problems existing in the related technology that it is difficult to effectively observe the rotor position under the condition of a power grid fault and it is difficult to achieve the indicators of the power grid's fault ride-through capability.

[0007] The present invention adopts the following technical solutions to achieve the above-mentioned purpose:

[0008] According to a first aspect of an embodiment of the present application, a position sensorless control method for a doubly-fed induction wind turbine is provided, comprising:

[0009] Collect three-phase stator current values ​​and rotor current values ​​to obtain the stator current vector in the stator stationary coordinate system and the rotor current vector in the rotor stationary coordinate system;

[0010] Inputting the stator current vector and the rotor current vector into a phase-locked loop to obtain an angle between the stator current vector and the rotor current vector;

[0011] Removing the grid voltage from the closed-loop control loop and using only the grid voltage as a feedforward term to perform feedforward compensation on the angle;

[0012] The DC bus voltage is maintained stable through the grid-side PWM converter; an active power instruction is given according to the rotor speed; and the active power instruction and reactive power instruction are converted into instructions for the quadrature and direct axis components of the rotor current through the rotor-side PWM converter to achieve decoupling control of active and reactive power.

[0013] According to a second aspect of an embodiment of the present application, there is provided a position sensorless control system for a doubly-fed induction wind turbine, comprising:

[0014] An acquisition module is used to acquire three-phase stator current values ​​and rotor current values ​​to obtain a stator current vector in a stator stationary coordinate system and a rotor current vector in a rotor stationary coordinate system;

[0015] A phase-locked loop control module, configured to input the stator current vector and the rotor current vector into a phase-locked loop to obtain an angle between the stator current vector and the rotor current vector;

[0016] A feedforward control module, configured to remove the grid voltage from the closed-loop control loop and use only the grid voltage as a feedforward term to perform feedforward compensation on the angle;

[0017] The DFIG control module is used to maintain the DC bus voltage stability through the grid-side PWM converter; provide active power instructions based on the rotor speed; and convert the active power instructions and reactive power instructions into instructions for the quadrature and direct axis components of the rotor current through the rotor-side PWM converter to achieve decoupling control of active and reactive power.

[0018] According to a third aspect of the embodiments of the present application, there is provided an electronic device, including:

[0019] one or more processors;

[0020] a memory for storing one or more programs;

[0021] When the one or more programs are executed by the one or more processors, the one or more processors implement the method as described in the first aspect.

[0022] According to a fourth aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which computer instructions are stored. When the instructions are executed by a processor, the steps of the method described in the first aspect are implemented.

[0023] The technical solutions provided by the embodiments of the present application may have the following beneficial effects:

[0024] It can be seen from the above embodiments that the present application removes the grid voltage from the closed-loop control loop and uses the grid voltage as a feedforward item to perform feedforward compensation on the angle. This technical solution overcomes the problem that the existing DFIG position sensorless control strategy is difficult to achieve effective observation of the rotor position under the condition of a grid fault, thereby improving the fault ride-through capability of the DFIG wind power generation system under the position sensorless control strategy.

[0025] In addition, this application does not use any motor parameters in the phase-locked loop link, and only uses the stator self-inductance in the phase-locked loop link. , which overcomes the parameter drift problem of the existing DFIG position sensorless control strategy and improves the robustness of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0027] Figure 1 The present invention is a flow chart showing a position sensorless control method for a doubly-fed induction wind turbine according to an exemplary embodiment.

[0028] FIG2 is a Π-type equivalent circuit diagram of a DFIG wind turbine generator equivalent to the stator side according to an exemplary embodiment.

[0029] FIG3 shows the spatial position relationship among a stator, a rotor, a stator current, and a rotor current according to an exemplary embodiment.

[0030] FIG4 shows the performance of a DFIG wind turbine system when the grid voltage drops to 0.2 pu during t=1.5s~2.125s under the condition of using the position sensorless control method of the present invention according to an exemplary embodiment; wherein (a) is the three-phase stator voltage waveform; (b) and (c) are the compensation angle output by the voltage feedforward link and the error between the observed value and the actual value of the rotor position angle, respectively; (d) and (e) are the rotor current waveforms in the synchronous rotating coordinate system and the rotor current waveforms in the abc three-phase stationary coordinate system, respectively; (f) and (g) are the stator current waveforms in the synchronous rotating coordinate system and the rotor current waveforms in the abc three-phase stationary coordinate system, respectively.

[0031] FIG5 is a complete control block diagram of a DFIG including a rotor position observer and a DFIG control system according to an exemplary embodiment.

[0032] Figure 6 The present invention is a block diagram showing a position sensorless control system for a doubly-fed induction wind turbine according to an exemplary embodiment. DETAILED DESCRIPTION

[0033] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0034] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. As used in this application and the appended claims, the singular forms "a," "an," "the," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the term "and / or" as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0035] Figure 1 FIG5 is a flow chart of a position sensorless control method for a doubly fed induction wind turbine according to an exemplary embodiment; FIG6 is a complete control block diagram of a DFIG including a rotor position observer and a DFIG control system according to an exemplary embodiment. Figure 1 and Figure 5 As shown, the control method includes the following steps:

[0036] S1: Collect three-phase stator current values ​​and rotor current values ​​to obtain the stator current vector in the stator stationary coordinate system and the rotor current vector in the rotor stationary coordinate system;

[0037] Specifically, the three-phase stator current of the doubly fed induction generator is collected by current sensors. and three-phase rotor current The collected three-phase stator and rotor currents are converted to a two-phase stationary coordinate system through Clarke transformation:

[0038] (1)

[0039] (2)

[0040] Therefore, the stator current vector in the stator stationary coordinate system can be expressed as:

[0041] (3)

[0042] The rotor current vector in the rotor stationary coordinate system can be expressed as:

[0043] (4)

[0044] S2: Inputting the stator current vector and the rotor current vector into a phase-locked loop to obtain the angle between the stator current vector and the rotor current vector; this step includes the following sub-steps:

[0045] S21: Invert the stator current vector in the stator stationary coordinate system to obtain and compare it with the phase-rotated rotor current vector in the rotor stationary coordinate system Perform a vector cross multiplication operation, where Represents the stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between them is used to generate an error signal representing the phase deviation. ;

[0046] Specifically, according to Figure 2 DFIG shown The stator side voltage equation in the stator stationary reference coordinate system can be given by (5):

[0047] (5)

[0048] The stator flux expression is given by (6):

[0049] (6)

[0050] Rotor current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The coordinate transformation relationship of the stator is given by equation (7).

[0051] (7)

[0052] In equations (5)-(7), is the stator resistance, is the grid equivalent inductance, is the stator self-inductance, is the stator-rotor mutual inductance. , , , respectively, are the grid voltage, stator current, and stator flux vector in the stator stationary reference frame. is the rotor current vector in the stator stationary coordinate system. is the rotor current vector in the rotor stationary coordinate system. is the rotor position angle.

[0053] Substitute equation (6) into equation (5) and ignore the term containing the stator resistance grid inductance :

[0054] (8)

[0055] Equations (7) and (8) show that the phase angle of the negative-phase-sequence rotor current vector in the stator stationary coordinate system differs from the phase angle of the rotor current vector in the rotor stationary coordinate system by a difference :

[0056] (9)

[0057] Using the difference , perform a coordinate transformation on to rotate to the same phase as the negative-phase-sequence rotor current vector in the stator stationary coordinate system, and then perform a cross multiplication operation on the two, to obtain the error signal :

[0058] (10)

[0059] S22: input the error signal to a proportional-integral (PI) controller for processing, and the controller output directly corresponds to the rotor angular velocity ;

[0060] ​Specifically, the error signal ζ represents the phase deviation between the anti-phase stator current vector and the rotating rotor current vector in the stator stationary coordinate system. This error signal is input to the proportional-integral controller, and the mathematical expression of the controller is:

[0061] (11)

[0062] in, is the proportional gain coefficient, is the integral gain coefficient. Through the action of PI controller, when the error signal When it exists, the controller will generate corresponding output to adjust the rotor angular velocity , so that the error signal gradually decreases to zero, thus achieving phase locking.

[0063] This design uses the phase relationship between the stator current vector and the rotor current vector to obtain the rotor angular velocity through a closed-loop PI controller without using any motor parameters. .

[0064] S23: By the angular velocity Perform time domain integration to obtain the anti-phase stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between ;

[0065] S24: This angle It is sent back to the rotation conversion link of the rotor current vector to form a closed-loop control structure;

[0066] Specifically, the angle obtained in step S23 is : Feedback to the coordinate transformation link of the rotor current vector, used to adjust the rotor current vector The rotation angle of . Rotation transformation The rotor current vector is gradually aligned with the phase of the anti-phase stator current vector in the stator stationary coordinate system. When the two are completely aligned, the result of the cross product operation (error signal ) will approach zero, indicating that the PLL is locked.

[0067] Such closed-loop control obtains important intermediate variables Using this intermediate variable, the final rotor position angle can be obtained through the subsequent feedforward compensation link. In addition, the entire phase-locked loop does not introduce grid voltage, which ensures its stable operation under grid faults.

[0068] S3: removing the grid voltage from the closed-loop control loop and using only the grid voltage as a feedforward item to perform feedforward compensation on the angle; this step includes the following sub-steps:

[0069] S31: Based on the DFIG mathematical model, derive the mathematical relationship between the stator current vector, rotor current vector, and grid voltage vector equivalent to the stator stationary coordinate system;

[0070] Specifically, the mathematical relationship is given by equation (8).

[0071] S32: By observing the three-phase stator current information and the three-phase grid voltage information, the anti-phase stator current vector in the stator stationary coordinate system is derived using formula (8). The rotor current vector in the stator stationary coordinate system Phase difference ;

[0072] (12)

[0073] S33: Using the phase difference as a feedforward compensation item to perform feedforward compensation on the angle.

[0074] Specifically, the spatial relationship between the stator current, rotor current, stator, and rotor is as follows: Figure 3 As shown. The rotor position angle can be calculated by performing feedforward compensation using formula (9):

[0075] (13)

[0076] It is worth noting that the feedforward compensation term The stator current is directly calculated using grid voltage and stator current information. This design separates grid voltage information from the control loop, preventing the direct impact of drastically fluctuating grid voltage information on the control loop during a grid fault, and improving the system's fault ride-through capability.

[0077] S4: Maintaining DC bus voltage stability through the grid-side PWM converter; giving active power instructions according to the rotor speed; and converting the active power instructions and reactive power instructions into instructions for the quadrature and direct axis components of the rotor current through the rotor-side PWM converter to achieve decoupling control of active and reactive power.

[0078] The DC bus voltage is maintained stable by the grid-side PWM converter, including the following sub-steps:

[0079] A1: Collects the DC bus voltage value and compares it with the set DC bus voltage reference value to generate a voltage error signal;

[0080] Specifically, a voltage sensor is used to collect the voltage value at both ends of the DC bus. and the preset DC bus voltage reference value Compare and calculate the voltage error signal .

[0081] A2: Converts the voltage error signal The input is sent to the proportional-integral (PI) controller for processing to obtain the d-axis component command of the grid-side converter current;

[0082] Specifically, the voltage error signal Input to the proportional-integral (PI) controller, the output of the PI controller is the d-axis component command of the grid-side converter current :

[0083] (14)

[0084] A3: Collect the three-phase current of the grid-side converter and convert it to a synchronous rotating coordinate system to obtain the d-axis and q-axis current components;

[0085] Specifically, a current sensor is used to collect the three-phase current of the grid-side converter. , , First, the three-phase current is converted to a two-phase synchronous rotating coordinate system through Clarke transformation and Park transformation:

[0086] (15)

[0087] (16)

[0088] in is the grid voltage vector angle, typically obtained through a grid voltage phase-locked loop (PLL). Aligning the d-axis of the synchronously rotating coordinate system with the grid voltage vector facilitates subsequent independent decoupled control of the d- and q-axis currents.

[0089] A4: Subtract the d-axis and q-axis current command values ​​from the actual d-axis and q-axis current values ​​and send them to their respective PI controllers. Decoupling and compensating the outputs of the PI controllers generate d-axis and q-axis voltage control signals.

[0090] Specifically, the d-axis current command value The actual value of the d-axis current The difference is sent to the PI controller to get the output . Set the q-axis current command value and the actual value of q-axis current The difference is sent to the PI controller to get the output .

[0091] By decoupling and compensating the output of the above PI controller using equations (17) and (18), the d-axis and q-axis voltage control signals can be obtained.

[0092] (17)

[0093] (18)

[0094] Wherein, L is the inductive reactance of each phase incoming line reactor, is the grid voltage angular frequency.

[0095] A5: The d-axis and q-axis voltage control signals are transformed into three-phase modulation waveforms through coordinate inverse transformation, and the switching signals of the grid-side PWM converter are generated through space vector modulation (SVM) technology to achieve stable control of the DC bus voltage.

[0096] Specifically, the voltage control signal in the synchronous rotating coordinate system is first converted back to the two-phase stationary coordinate system through the inverse Park transform:

[0097] (19)

[0098] Then, the PWM switching signal is generated by space vector modulation technology (SVM) to control the DC bus voltage.

[0099] The active power instruction is given according to the rotor speed, including the following sub-steps:

[0100] B1: Based on the principle of Maximum Power Point Tracking (MPPT), establish the rotor speed and optimal active power The mapping relationship curve between them;

[0101] Specifically, the relationship between the optimal active power and rotor speed of a wind turbine can be expressed as:

[0102] (20)

[0103] in, is a constant related to wind turbines. is the number of motor pole pairs, is the gearbox ratio.

[0104] During actual wind turbine operation, accurate wind speed detection is difficult, making it impossible to directly generate the optimal speed command. Establishing a mapping curve between rotor speed and maximum output power is not the goal of speed control, but rather of operating the wind turbine within the optimal power curve, ultimately enabling the wind turbine to operate at the optimal speed.

[0105] B2: According to the current rotor speed observation value, the corresponding optimal active power point is searched on the mapping relationship curve (MPPT curve), and the found optimal active power value is used as the active power instruction;

[0106] Specifically, in actual operation, the speed obtained by the speed observer The optimal active power point is obtained on the MPPT curve by looking up the table and other methods, and is used as the active power Command value:

[0107] (twenty one)

[0108] The active power command and reactive power command are converted into commands of the quadrature and direct axis components of the rotor current by a rotor-side PWM converter to achieve decoupling control of active and reactive power, including:

[0109] C1: Based on the principle of field-oriented control, a mathematical model of the doubly-fed induction generator is established to determine the corresponding relationship between the active power output by the stator and the d-axis component of the rotor current, and between the reactive power output by the stator and the q-axis component of the rotor current;

[0110] Specifically, under the stator voltage-oriented control strategy, the active power and reactive power output by the stator can be expressed using Equations (22) and (23):

[0111] (twenty two)

[0112] (twenty three)

[0113] C2: Converts the total electromagnetic power command from MPPT control into the command value of stator output active power;

[0114] Specifically, according to the relationship between the active power output by the DFIG stator and the total electromagnetic power, the total electromagnetic power command value can be converted into the stator output power command value

[0115] (twenty four)

[0116] in, is the stator copper loss, ; Slip .

[0117] C3: converting the reactive power command into a rotor current q-axis component command value through the corresponding relationship;

[0118] Specifically, the reactive power command value output by the DFIG stator to the grid is It has nothing to do with maximum wind energy tracking, and its instructions are given by the designer based on the needs of the power grid or the needs of DFIG operation optimization.

[0119] C4: Compare the active power and reactive power actually output by the stator with the command value to obtain the error signal:

[0120] Specifically, the stator actually outputs active power The expression is:

[0121] (25)

[0122] The stator output active power command value and actual stator output power After subtraction, the error signal is obtained :

[0123] (26)

[0124] Similarly, the actual reactive power output of the stator is for:

[0125] (27)

[0126] The reactive power command value output by the stator and actual stator output power After subtraction, the error signal is obtained :

[0127] (28)

[0128] C5: Input the error signal into respective PI controllers for processing to obtain command values ​​of the d-axis and q-axis components of the rotor current.

[0129] Specifically, the error signal Send it to the PI controller to get the rotor current d-axis component command value ; The error signal Send it to the PI controller to get the rotor current q-axis component command value .

[0130] C6: Subtract the command value from the actual rotor current d-axis and q-axis components and send them to the respective PI controllers; decouple and compensate the output of the PI controller to obtain the rotor voltage d-axis and q-axis component command values; generate the switching signal of the rotor-side PWM converter through space vector modulation technology, thereby realizing decoupling control of active and reactive power.

[0131] Specifically, the d-axis component of the rotor current and the rotor current d-axis component command value The difference is sent to the PI controller to get the output ; The q-axis component of the rotor current and the rotor current q-axis component command value The difference is sent to the PI controller to get the output .

[0132] Through formula (29) and formula (30) 、 After decoupling compensation, the rotor voltage d-axis component command value is obtained and the rotor voltage q-axis component command value .

[0133] (29)

[0134] (30)

[0135] in, is the magnetic flux leakage coefficient, is the rotor self-inductance, For mutual induction, is the stator flux, slip angular velocity , is the grid angular frequency.

[0136] By using space vector modulation technology, the switching signal of the rotor-side PWM converter is generated according to the rotor voltage d-axis and q-axis component command values, thereby achieving decoupling control of the DFIG active power and reactive power.

[0137] The specific operation effect of the present invention can be seen through Figure 4 To characterize. Grid voltage Fall to ,Keep Later Restore to ,like Figure 4 As shown in (a) in Figure 1. Before the voltage drop, the DFIG wind power generation system is in a stable state, the grid voltage feedforward compensation link outputs a stable compensation value, and the static observation error of the rotor position angle is zero. At this moment, the grid voltage drops to .like Figure 4 As shown in (b), the feedforward compensation link can quickly respond to changes in the grid voltage; and the phase-locked loop link can still effectively observe the angle between the rotor current vector and the measured current vector because it does not contain the grid voltage component. Figure 4 As shown in (c) in FIG, during the entire grid voltage drop process and the grid voltage recovery process, the maximum error of the angle estimation of the position sensorless control method proposed in the present invention is only 0.1 radian. Figure 4(d) and (e) are the rotor current waveforms in the synchronous rotating coordinate system and the three-phase stationary coordinate system respectively. The system can effectively control the rotor quadrature and direct axis currents before, during, and after voltage recovery. , which shows that the DFIG wind power generation system does not become unstable during the fault ride-through process. The position sensorless control method proposed in this invention has strong robustness and fault ride-through capability.

[0138] As can be seen from the above embodiments, the present invention removes the grid voltage information from the phase-locked loop closed-loop control system and introduces a grid voltage feedforward compensation term to compensate the phase-locked loop output angle to obtain the rotor position angle observation value. and rotor speed When the power grid fails, since the grid voltage information of the faulty power grid does not directly enter the closed-loop control system, the rotor position observer proposed in this application can still achieve effective observation of the rotor position. and rotor speed By substituting the subsequent maximum wind power tracking link and the active and reactive power decoupling control link, effective control of the motor can be achieved under normal operating conditions and grid fault conditions.

[0139] Corresponding to the aforementioned embodiment of the position sensorless control method for a doubly-fed induction wind generator, the present application also provides an embodiment of a position sensorless control system for a doubly-fed induction wind generator.

[0140] Figure 6 FIG1 is a block diagram of a position sensorless control system for a doubly-fed induction wind turbine according to an exemplary embodiment. Figure 6 , the device comprises:

[0141] Acquisition module 1, used to collect three-phase stator current values ​​and rotor current values, and obtain the stator current vector in the stator stationary coordinate system and the rotor current vector in the rotor stationary coordinate system;

[0142] A phase-locked loop control module 2, configured to input the stator current vector and the rotor current vector into a phase-locked loop to obtain an angle between the stator current vector and the rotor current vector;

[0143] A feedforward control module 3 is configured to remove the grid voltage from the closed-loop control loop and use only the grid voltage as a feedforward item to perform feedforward compensation on the angle;

[0144] The DFIG control module 4 is used to maintain the DC bus voltage stability through the grid-side PWM converter; provide active power instructions according to the rotor speed; and convert the active power instructions and reactive power instructions into instructions for the quadrature and direct axis components of the rotor current through the rotor-side PWM converter to achieve decoupling control of active and reactive power.

[0145] As to the apparatus in the above embodiments, the specific ways in which the respective modules perform operations have been described in detail in the embodiments related to the method, and thus will not be described in detail here.

[0146] For the apparatus embodiments, since they basically correspond to the method embodiments, the relevant parts are described in the part of the method embodiments. The apparatus embodiments described above are merely illustrative, wherein the units described as separate components can or can not be physically separate, and the components displayed as units can or can not be physical units, i.e., can be located in one place, or can be distributed on multiple network units. Some or all of the modules can be selected to achieve the purposes of the present application according to actual needs. Those skilled in the art can understand and implement without creative labor.

[0147] Correspondingly, the present application also provides an electronic device, comprising: one or more processors; a memory for storing one or more programs; when the one or more programs are executed by the one or more processors, the one or more processors implement the above-mentioned method for position sensorless control of a doubly-fed induction wind power generator.

[0148] Correspondingly, the present application also provides a computer readable storage medium, which stores computer instructions, and the instructions are executed by a processor to implement the above-mentioned method for position sensorless control of a doubly-fed induction wind power generator.

[0149] Those skilled in the art will readily understand other embodiments of the present application upon considering the description and practicing the content disclosed herein. The present application is intended to cover any variations, uses, or adaptive changes of the present application that follow the general principles of the present application and include common knowledge or conventional technical means in the art that are not disclosed by the present application. The specification and examples are only regarded as exemplary, and the true scope and spirit of the present application are indicated by the claims.

[0150] It should be understood that the present application is not limited to the precise construction that has been described above and shown in the accompanying drawings, and that various modifications and changes can be made without departing from the scope thereof. The scope of the present application is only limited by the appended claims.

Claims

1. A position sensorless control method for a doubly-fed induction wind turbine, characterized in that: include: Collect three-phase stator current values ​​and rotor current values ​​to obtain the stator current vector in the stator stationary coordinate system and the rotor current vector in the rotor stationary coordinate system; Inputting the stator current vector and the rotor current vector into a phase-locked loop to obtain an angle between the stator current vector and the rotor current vector; Removing the grid voltage from the closed-loop control loop and using only the grid voltage as a feedforward term to perform feedforward compensation on the angle; Maintaining DC bus voltage stability through a grid-side PWM converter; issuing active power instructions based on rotor speed; and converting the active power instructions and reactive power instructions into instructions for the quadrature and direct axis components of the rotor current through a rotor-side PWM converter to achieve decoupling control of active and reactive power. The stator current vector and the rotor current vector are input into a phase-locked loop to obtain the angle between the stator current vector and the rotor current vector, including: The stator current vector in the stator stationary coordinate system is Perform inversion treatment to obtain and compare it with the phase-rotated rotor current vector in the rotor stationary coordinate system Perform a vector cross multiplication operation, where Represents the stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between them is used to generate an error signal representing the phase deviation. ; The error signal The input is processed by the proportional-integral PI controller, and the controller output directly corresponds to the rotor angular velocity ; By the angular velocity Perform time domain integration to obtain the anti-phase stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between ; This angle It is sent back to the rotation conversion link of the rotor current vector to form a closed-loop control structure.

2. The method according to claim 1, characterized in that The grid voltage is removed from the closed-loop control loop, and only the grid voltage is used as a feedforward term to perform feedforward compensation on the angle, including: Based on the DFIG mathematical model, the mathematical relationship between the stator current vector, rotor current vector, and grid voltage vector equivalent to the stator stationary coordinate system is obtained; By observing the three-phase stator current information and the three-phase grid voltage information, the phase difference between the anti-phase stator current vector and the rotor current vector is calculated using the mathematical relationship; The phase difference is used as a feedforward compensation term to compensate the angle Perform feedforward compensation.

3. The method according to claim 1, characterized in that Maintaining DC bus voltage stability through the grid-side PWM converter includes: Collect the DC bus voltage value and compare it with the set DC bus voltage reference value to generate a voltage error signal; Inputting the voltage error signal into a proportional-integral (PI) controller for processing to obtain a d-axis component instruction of the grid-side converter current; Collect the three-phase current of the grid-side converter and convert it to a synchronous rotating coordinate system to obtain the d-axis and q-axis current components; The actual value of the d-axis current is compared with the d-axis current command value, and a d-axis voltage control signal is generated through a PI controller; the actual value of the q-axis current is compared with the q-axis current command value, and a q-axis voltage control signal is generated through a PI controller; The d-axis and q-axis voltage control signals are transformed into three-phase modulation waveforms through coordinate inverse transformation, and the switching signals of the grid-side PWM converter are generated through space vector modulation technology, thereby achieving stable control of the DC bus voltage.

4. The method according to claim 1, wherein Give active power instructions based on the rotor speed, including: Based on the maximum power point tracking principle, a mapping curve between rotor speed and optimal active power is established; According to the current rotor speed observation value, the corresponding optimal active power point is searched on the mapping relationship curve, and the optimal active power value found is used as the active power instruction.

5. The method according to claim 1, wherein The active power command and reactive power command are converted into commands of quadrature and direct axis components of the rotor current by a rotor-side PWM converter to achieve decoupling control of active power and reactive power, including: Based on the principle of field-oriented control, a mathematical model of the doubly-fed induction generator is established to determine the corresponding relationship between active power and the d-axis component of the rotor current, and between reactive power and the q-axis component of the rotor current. Converting the active power command from the MPPT control into a rotor current d-axis component command value through the corresponding relationship; Converting the reactive power command into a rotor current q-axis component command value according to the corresponding relationship; Comparing the actual values ​​of the d-axis and q-axis components of the rotor current with the command values ​​to generate a current error signal; The current error signal is input into respective PI controllers for processing to obtain control signals of the d-axis and q-axis components of the rotor voltage; the switching signal of the rotor-side PWM converter is generated through space vector modulation technology, thereby realizing decoupling control of active and reactive power.

6. A position sensorless control system for a doubly-fed induction wind turbine, characterized in that: include: An acquisition module is used to acquire three-phase stator current values ​​and rotor current values ​​to obtain a stator current vector in a stator stationary coordinate system and a rotor current vector in a rotor stationary coordinate system; A phase-locked loop control module, configured to input the stator current vector and the rotor current vector into a phase-locked loop to obtain an angle between the stator current vector and the rotor current vector; A feedforward control module, configured to remove the grid voltage from the closed-loop control loop and use only the grid voltage as a feedforward term to perform feedforward compensation on the angle; The DFIG control module is used to maintain the DC bus voltage stability through the grid-side PWM converter; provide active power instructions based on the rotor speed; and convert the active power instructions and reactive power instructions into instructions for the quadrature and direct axis components of the rotor current through the rotor-side PWM converter to achieve decoupling control of active and reactive power. The stator current vector and the rotor current vector are input into a phase-locked loop to obtain the angle between the stator current vector and the rotor current vector, including: The stator current vector in the stator stationary coordinate system is Perform inversion treatment to obtain and compare it with the phase-rotated rotor current vector in the rotor stationary coordinate system Perform a vector cross multiplication operation, where Represents the stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between them is used to generate an error signal representing the phase deviation. ; The error signal The input is processed by the proportional-integral PI controller, and the controller output directly corresponds to the rotor angular velocity ; By the angular velocity Perform time domain integration to obtain the anti-phase stator current vector in the stator stationary coordinate system The rotor current vector in the rotor stationary coordinate system The angle between ; This angle It is sent back to the rotation conversion link of the rotor current vector to form a closed-loop control structure.

7. An electronic device, characterized in that: include: one or more processors; a memory for storing one or more programs; When the one or more programs are executed by the one or more processors, the one or more processors implement the method according to any one of claims 1 to 5.

8. A computer-readable storage medium having computer instructions stored thereon, characterized in that: When the instruction is executed by a processor, the steps of the method according to any one of claims 1 to 5 are implemented.

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