Control method and device for double-drive variable pitch system of wind turbine generator

Abstract

The invention relates to a control method and device for a double-drive variable pitch system of a wind turbine generator. A position controller outputs a position response signal to a speed controller according to a received variable pitch instruction and an angular position signal of a corresponding motor; the speed controller outputs a current response signal to the current controller according to the received position response signal; the current controller outputs a voltage response signal according to the received current response signal, and sends a switching signal to the inverter through the space vector pulse width modulation module; the inverter outputs a control signal to the corresponding motor according to the received switching signal, so that the motor responds to the variable pitch instruction and feeds back actual current to the current controller; and a position angle signal generated during the period that the motor responds to the variable pitch instruction is returned to the corresponding position controller, and the generated position angle signal is subjected to rotating speed correction to obtain a rotating speed given correction value which is sent to the corresponding speed controller.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbines, and in particular to a control method and device for a dual-drive variable pitch system of a wind turbine. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The dual-drive pitch system means that each blade of the wind turbine is equipped with two independent drivers to control its pitch angle. This design makes the pitch operation of each blade more flexible and precise to meet the operating requirements under different wind speed and wind direction conditions.

[0004] Most of the motor control methods for dual-drive variable pitch systems currently use the master-slave control method, where the master drive responds to the position command of the master control system, and the slave drive responds to the master drive command. This control determines that there is a certain lag in the slave motor following the control command, and the feedback information of the slave motor cannot be transmitted to the master motor. Therefore, the slave motor will not affect the master motor after being disturbed, making it impossible to eliminate the synchronization error. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides a control method and device for a dual-drive variable pitch system of a wind turbine, which achieves the purpose of synchronizing the speed and torque of the dual motors in the dual-drive variable pitch system of the wind turbine without increasing the hardware cost investment.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A first aspect of the present invention provides a control method for a wind turbine dual-drive pitch control system, comprising the following steps:

[0008] The position controller outputs a position response signal to the speed controller according to the received pitch control command and the angular position signal of the corresponding motor;

[0009] The speed controller outputs a current response signal to the current controller according to the received position response signal;

[0010] The current controller outputs a voltage response signal according to the received current response signal, and sends a switching signal to the inverter through a space vector pulse width modulation module;

[0011] The inverter outputs a control signal to the corresponding motor according to the received switch signal, so that the motor responds to the pitch change command and feeds back the actual current to the current controller;

[0012] The position angle signal generated during the motor's response to the pitch change command is returned to the corresponding position controller. The generated position angle signal is also corrected by the speed to obtain a speed setting correction value, which is sent to the corresponding speed controller.

[0013] Furthermore, the position controller is an active disturbance rejection controller.

[0014] Furthermore, the position controller includes a dilation observer, nonlinear feedback and a transition process.

[0015] Furthermore, the extended observer approximates each order state variable through a nonlinear function and extracts the high-order disturbance term, which is compensated in the final output control signal, as shown in the following formula:

[0016]

[0017] Among them, z1, z2, z3 are the observation values ​​of the expanded observer, β 01 , β 02 , β 03 is a set of adjustable parameters for output error, y is the measured value of the first-order state variable of the system, e1 is the feedback error of the system, u is the input of the controlled quantity, b0 is the compensation factor, Fal() function is the optimal comprehensive control function, e is the error of z tracking the output x, α is the nonlinear factor, and h is the filtering factor.

[0018] Furthermore, nonlinear feedback uses error feedback to establish a control signal as shown below:

[0019]

[0020] Among them, e1 and e2 are the errors between the observed and actual quantities, u is the system control quantity, u0 is the output value of the nonlinear feedback, z1, z2, z3 are the observed values ​​of the expanded observer, b0 is the compensation factor, and h is the filtering factor.

[0021] Furthermore, the transition process is specifically as follows: obtaining the follow value and differential value of the input signal, as shown in the following formula:

[0022]

[0023] Among them, v is the input signal, and two signals v1 and v2 are output. v1 tracks the input signal v, v2 is the differential signal of v1, r0 is the speed factor, h is the filter factor, e is the tracking error, fhan() function is the fast optimal control synthesis function, and sign() function is the sign function.

[0024] Furthermore, the speed controller generates the q-axis current based on the proportional-integral controller, and the d-axis current is set to zero.

[0025] Furthermore, the current controller generates d-axis and q-axis voltage values, and the voltage values ​​are converted by the space vector pulse width modulation module to generate inverter switching signals, and are output to the inverter.

[0026] Furthermore, the speed correction is as follows:

[0027]

[0028] V1*, is the input value of the speed controller of driver A and driver B, that is, the speed setting correction value, V1 and V2 are the output values ​​of the position controller, k is the gain coefficient of the gain calculation module, θ1 is the position angle feedback signal of motor 1, θ2 is the position angle feedback signal of motor 2, driver A corresponds to motor 1, and driver B corresponds to motor 2.

[0029] The second aspect of the present invention provides a control device for a dual-drive variable pitch system of a wind turbine group, comprising at least two drivers and corresponding motors, each driver comprising a position controller, a speed controller, a current controller and an inverter which are communicatively connected in sequence; the signal output end of the inverter is communicatively connected to the signal input end of the current controller, the motor has a rotating transformer, the rotating transformer is communicatively connected to the position controller and the gain calculation module respectively, and the output end of the gain calculation module is communicatively connected to the signal input end of the speed controller.

[0030] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0031] 1. During the response to the pitch command, the motor position angle signal obtained is fed back to the corresponding position controller. At the same time, by comparing the angle difference of the position angle signals of the two motors, the revised value of the speed is calculated for each driver and fed back to the corresponding speed controller, thereby adjusting the speed of the two motors: for the motor with advanced position, the speed controller slows down its speed; for the motor with lagging position, the speed controller speeds up its speed. In this way, the dynamic balance of the speed and torque of the two motors is achieved, the error problem is solved, and the life of the pitch bearing is increased.

[0032] 2. Through the cross-coupling topology and the use of anti-disturbance control controller, the hyperbolic pitch control performance of the wind turbine is significantly improved, with higher control accuracy and faster response speed, and the load on the pitch bearing is reduced. It is suitable for frequent control of independent pitch and is suitable for the pitch system control needs in the field of large-megawatt wind power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0034] Figure 1 is a schematic diagram of a pitch control process provided by one or more embodiments of the present invention;

[0035] Figure 2 is a schematic diagram of an active disturbance rejection controller provided by one or more embodiments of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0037] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0038] As introduced in the background technology, most of the motor control methods for dual-drive variable pitch systems currently use a master-slave control method, where the master driver responds to the position command of the master control system, and the slave driver responds to the master driver command. This control determines that there is a certain lag in the slave motor following the control command, and the feedback information of the slave motor cannot be transmitted to the master motor. Therefore, the slave motor will not affect the main motor after being disturbed, making it impossible to eliminate the synchronization error.

[0039] Therefore, the following embodiments provide a control method and device for a dual-drive pitch system of a wind turbine. Through a cross-coupling topology and the use of an anti-disturbance control controller, the hyperbolic pitch control performance of the wind turbine is significantly improved. It has high control accuracy and fast response speed, reduces the load on the pitch bearing, is suitable for frequent control of independent pitch, and is suitable for the pitch system control requirements in the field of large-megawatt wind power generation.

[0040] Embodiment 1:

[0041] A control method for a wind turbine dual-drive variable pitch system comprises the following steps:

[0042] The position controller outputs a position response signal to the speed controller according to the received pitch control command and the angular position signal of the corresponding motor;

[0043] The speed controller outputs a current response signal to the current controller according to the received position response signal;

[0044] The current controller outputs a voltage response signal according to the received current response signal, and sends a switching signal to the inverter through a space vector pulse width modulation module;

[0045] The inverter outputs a control signal to the corresponding motor according to the received switch signal, so that the motor responds to the pitch change command and feeds back the actual current to the current controller;

[0046] The position angle signal generated during the motor's response to the pitch change command is returned to the corresponding position controller. The generated position angle signal is also corrected by the speed to obtain a speed setting correction value, which is sent to the corresponding speed controller.

[0047] Each drive includes a position controller, a speed controller, a current controller and an inverter. A sensor in the motor corresponding to the drive provides position angle feedback (for example, position angle feedback is obtained through a rotary transformer), and the feedback signal is transmitted to the position controller.

[0048] The position controller adopts an active disturbance rejection controller (ADRC), which can significantly improve the control performance and anti-interference ability, and achieve better dynamic response and steady-state accuracy.

[0049] The ADRC consists of three parts: extended observer, nonlinear feedback and transition process.

[0050] Among them, the transition process can prevent the phenomenon such as feedback overshoot caused by a large error between the given value and the actual value when the given value changes suddenly; the expanded observer approximates the state variables of each order through nonlinear functions and extracts high-order disturbance terms to compensate for the final output control signal; nonlinear feedback uses error feedback to establish the control signal.

[0051] Both the speed controller and the current controller use vector control methods. Specifically, the speed controller is used as the outer loop, using a proportional-integral (PI) controller to generate the q-axis current, while the d-axis current is set to zero. The current controller is used as the inner loop to generate d-axis and q-axis voltage values, which are converted by the SVPWM (space vector pulse width modulation) module to generate inverter switching signals and output to the inverter, thereby controlling the operation of the corresponding motor.

[0052] In addition, the position angle feedback signal of the motor is also transmitted to each driver respectively. By comparing the position angle difference between the two motors, the speed given correction value 1 and the speed given correction value 2 are calculated in the gain calculation module in each driver respectively.

[0053] The gain calculation module feeds these speed correction values ​​back to the speed controller input to adjust the speed of the two motors: for the motor with advanced position, the speed controller slows down its speed; for the motor with lagging position, the speed controller speeds up its speed. In this way, the dynamic balance of the speed and torque of the two motors is achieved, and the life of the variable pitch bearing is increased.

[0054] like Figure 1 As shown, the wind turbine dual-drive variable pitch control system includes two drivers, driver A and driver B. Each driver has a corresponding motor. Driver A corresponds to motor 1, and driver B corresponds to motor 2.

[0055] Each drive consists of a position controller, a speed controller, a current controller and an inverter.

[0056] The position controller receives the angular position signal of the corresponding motor obtained from the rotary transformer and uses an anti-disturbance control controller to perform position control.

[0057] The speed controller uses a PI controller to generate the q-axis current, and the d-axis current is zero.

[0058] The current controller generates the d-axis and q-axis voltage values, generates switching signals through the SVPWM module and outputs them to the corresponding inverter.

[0059] The inverter outputs a control signal to the corresponding motor according to the received switching signal, so that the motor responds to the pitch control instruction. The position angle signal generated by the motor is returned to the corresponding position controller. At the same time, after gain calculation, the obtained speed setting correction value is sent to the corresponding speed controller.

[0060] Active disturbance rejection control is a new control method based on the PID control algorithm. It is independent of the control object model and does not distinguish between internal and external disturbances. Therefore, in the wind power generation system, the impact of wind speed fluctuations and load changes on the entire generator set is constantly changing, and constantly adjusting the blade angle for opening and feathering has become the norm. By real-time estimation and compensation for disturbances caused by wind speed fluctuations and load changes, the adaptive controller ensures that the variable pitch dual-drive system is more stable and reduces the load on the blades caused by frequent pitch changes.

[0061] The structure of the active disturbance rejection controller is as follows: Figure 2 As shown, it includes expansion observer, nonlinear feedback and transition process.

[0062] The transition process has a strong processing capability for the output signal. Even for discontinuous or random noise input signals, fast overshoot-free tracking and high-quality differentials can be achieved. The transition process is shown in the following formula. For the input signal v, two signals v1 and v2 are output, where v1 tracks the input signal v, and v2 is the differential signal of v1. That is, the follow value v1 and differential value v2 of the input signal are given in the transition process. The expression is as follows:

[0063]

[0064] In the formula, r0 is the speed factor. The larger the r0 is, the faster the input signal is tracked. h is the filter factor and e is the tracking error. The fhan() function is a fast optimal control comprehensive function. The internal variables of this mathematical function have no actual meaning. The sign() function is a sign function.

[0065] The fhan() function in this embodiment outputs a result formula after describing four variable inputs, as shown in the following formula:

[0066]

[0067] The calculation formula of the extended observer is as follows:

[0068]

[0069]

[0070] Among them, z1, z2, z3 are the observation values ​​of the expanded observer, β 01 , β 02 , β 03 is a set of adjustable parameters for output error, y is the measured value of the first-order state variable of the system, e1 is the feedback error of the system, u is the input of the controlled quantity, and b0 is the compensation factor. The Fal() function is the optimal comprehensive control function, e is the error of z tracking the output x, α is the nonlinear factor, and h is the filter factor.

[0071] Nonlinear feedback, as shown below:

[0072]

[0073] Among them, e1, e2 are the errors between the observed quantity and the actual quantity, u is the system control quantity, and u0 is the output value of the nonlinear feedback.

[0074] The above constitutes the calculation process of the entire ADRC. The observer can be iterated multiple times to improve the observation accuracy.

[0075] The two drivers receive the motor position angle feedback signals respectively, the motor 1 feedback signal angle θ1, the motor 2 feedback signal angle θ2. Each driver is equipped with the same gain calculation module and calculates the speed correction value. The calculation formula of the speed gain module is as follows.

[0076]

[0077] Among them, V1 * , is the input value of the speed controller of driver A and driver B, V1 and V2 are the output values ​​of the anti-disturbance controller, k is the gain coefficient of the gain calculation module, and the gain calculation module feeds back the speed correction value to the input of the speed controller to adjust the motor speed to ensure the balance of speed and torque of the two motors.

[0078] The above process uses a cross-coupling topology and an anti-disturbance control controller. The cross-coupling topology can control the speed of two motors at the same time. Compared with the master-slave control method, the feedback value of the master motor speed is used as the input value of the slave motor speed, which can improve the response speed of the entire system. The use of an anti-disturbance control controller to replace the traditional PI or PID controller has a significant effect in resisting interference, thereby improving control accuracy. Therefore, this method significantly improves the hyperbolic pitch control performance of the wind turbine generator set, has higher control accuracy and faster response speed, reduces the load on the pitch bearing, is suitable for frequent control of independent pitch, and is suitable for the pitch system control requirements in the field of large megawatt wind power generation.

[0079] Embodiment 2:

[0080] The present embodiment provides a control method for a wind turbine dual-drive variable pitch system required to implement the above-mentioned control method, including at least two drivers and corresponding motors, each driver including a position controller, a speed controller, a current controller and an inverter which are communicatively connected in sequence; the signal output end of the inverter is communicatively connected to the signal input end of the current controller, the motor has a rotating transformer, the rotating transformer is communicatively connected to the position controller and the gain calculation module respectively, and the output end of the gain calculation module is communicatively connected to the signal input end of the speed controller.

[0081] Through the cross-coupling topology and the use of an anti-disturbance control controller, the hyperbolic pitch control performance of the wind turbine is significantly improved. It has higher control accuracy and faster response speed, reduces the load on the pitch bearing, and is suitable for frequent control of independent pitches and for the pitch system control needs in the field of large-megawatt wind power generation.

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A control method for a wind turbine dual-drive variable pitch system, characterized in that: The following steps are involved: The position controller outputs a position response signal to the speed controller according to the received pitch control command and the angular position signal of the corresponding motor; The speed controller outputs a current response signal to the current controller according to the received position response signal; The current controller outputs a voltage response signal according to the received current response signal, and sends a switching signal to the inverter through a space vector pulse width modulation module; The inverter outputs a control signal to the corresponding motor according to the received switch signal, so that the motor responds to the pitch change command and feeds back the actual current to the current controller; The position angle signal generated during the motor's response to the pitch change command is returned to the corresponding position controller. The generated position angle signal is also corrected by the speed to obtain a speed setting correction value, which is sent to the corresponding speed controller.

2. A control method for a wind turbine dual-drive variable pitch system according to claim 1, characterized in that: The position controller is an active disturbance rejection controller.

3. A control method for a wind turbine dual-drive variable pitch system according to claim 1, characterized in that: The position controller includes an expansion observer, nonlinear feedback and a transition process.

4. A control method for a wind turbine dual-drive variable pitch system as claimed in claim 3, characterized in that: The extended observer approximates each order state variable through a nonlinear function and extracts a high-order disturbance term, which is compensated in the final output control signal, as shown in the following formula: Among them, z1, z2, z3 are the observation values ​​of the expanded observer, β 01 , β 02 , β 03 is a set of adjustable parameters for output error, y is the measured value of the first-order state variable of the system, e1 is the feedback error of the system, u is the input of the controlled quantity, b0 is the compensation factor, Fal() function is the optimal comprehensive control function, e is the error of z tracking the output x, α is the nonlinear factor, and h is the filtering factor.

5. A control method for a wind turbine dual-drive variable pitch system as claimed in claim 3, characterized in that: The nonlinear feedback uses error feedback to establish a control signal as shown in the following equation: Among them, e1 and e2 are the errors between the observed and actual quantities, u is the system control quantity, u0 is the output value of the nonlinear feedback, z1, z2, z3 are the observed values ​​of the expanded observer, b0 is the compensation factor, and h is the filtering factor.

6. A control method for a wind turbine dual-drive variable pitch system according to claim 3, characterized in that: The transition process is as follows: the follow value and differential value of the input signal are obtained, as shown in the following formula: Among them, v is the input signal, and two signals v1 and v2 are output. v1 tracks the input signal v, v2 is the differential signal of v1, r0 is the speed factor, h is the filter factor, e is the tracking error, fhan() function is the fast optimal control synthesis function, and sign() function is the sign function.

7. A control method for a wind turbine dual-drive variable pitch system according to claim 1, characterized in that: The speed controller generates a q-axis current based on a proportional-integral controller, and the d-axis current is set to zero.

8. A control method for a wind turbine dual-drive variable pitch system according to claim 1, characterized in that: The current controller generates d-axis and q-axis voltage values, and the voltage values ​​are converted by the space vector pulse width modulation module to generate inverter switching signals, and are output to the inverter.

9. A control method for a wind turbine dual-drive variable pitch system according to claim 1, characterized in that: The speed correction is specifically: in, is the input value of the speed controller of driver A and driver B, that is, the speed setting correction value, V1 and V2 are the output values ​​of the position controller, k is the gain coefficient of the gain calculation module, θ1 is the position angle feedback signal of motor 1, θ2 is the position angle feedback signal of motor 2, driver A corresponds to motor 1, and driver B corresponds to motor 2.

10. A device for implementing the control method according to any one of claims 1 to 9, characterized in that: It includes at least two drivers and corresponding motors, each driver includes a position controller, a speed controller, a current controller and an inverter which are communicatively connected in sequence; the signal output end of the inverter is communicatively connected to the signal input end of the current controller, the motor has a rotary transformer, the rotary transformer is communicatively connected to the position controller and the gain calculation module respectively, and the output end of the gain calculation module is communicatively connected to the signal input end of the speed controller.

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