阅读说明：本技术 一种永磁直驱风机主控系统机组自动启停的控制方法 (Control method for automatic start and stop of permanent magnet direct drive fan main control system unit ) 是由 王奔 徐卫峰 牛洪海 陈俊 吴波 王淑超 于 2019-03-19 设计创作，主要内容包括：本发明公开一种永磁直驱风机主控系统机组自动启停的控制方法,使用状态机切换方法实现风机的启停过程控制,将机组在启动运行并网过程中的状态分为初始化模式、待机模式、启动模式、预加速模式、加速模式、并网模式、停机模式、服务模式,在启动过程中机组每到达一个模式,在该模式下具备相应的控制目标,当电机转速、叶片桨距角及延时时间达到设定值后,机组进入下一个状态机模式。此种控制方法可实现机组在无人值守的情况下根据外界环境及机组自身状况实现风机自动启停,启停过程中主控系统与变流器、变桨系统协同控制,最终保障机组的安全稳定运行。(The invention discloses a control method for automatically starting and stopping a permanent magnet direct drive fan main control system unit, which is characterized in that a state machine switching method is used for realizing the control of the starting and stopping process of a fan, the state of the unit in the starting, running and grid-connected process is divided into an initialization mode, a standby mode, a starting mode, a pre-acceleration mode, an acceleration mode, a grid-connected mode, a shutdown mode and a service mode, the unit has a corresponding control target in the mode when reaching one mode in the starting process, and the unit enters the next state machine mode when the rotating speed of a motor, the pitch angle of a blade and the delay time reach set values. The control method can realize automatic starting and stopping of the fan of the unit under the unattended condition according to the external environment and the self condition of the unit, and the main control system, the converter and the variable pitch system are cooperatively controlled in the starting and stopping process, so that the safe and stable operation of the unit is finally ensured.)

1. A control method for automatic start and stop of a permanent magnet direct drive fan main control system unit is characterized by comprising the following steps: the method comprises the steps that a state machine switching method is used for realizing the control of the starting and stopping processes of the fan, the unit has a corresponding control target in each mode when the unit reaches one mode in the starting process, and the unit enters the next state machine mode when the rotating speed of the motor, the pitch angle of the blades and the delay time reach set values.

2. The control method according to claim 1, characterized in that: dividing the state of the unit in the process of starting, running and grid-connection into an initialization mode, a standby mode, a starting mode, a pre-acceleration mode, an acceleration mode, a grid-connection mode, a shutdown mode and a service mode, and switching the state machine mode of the unit according to the following steps:

Step 1, a master control system carries out self-checking in an initialization mode, initializes system parameters and global variables, and enters a standby mode state after initialization is passed;

Step 2, in the standby mode, when the global shutdown level and the global yaw level are both smaller than a set value, and the draught fan is in the maximum feathering angle state, the self-checking of the converter is completed; pressing a starting button on a tower footing cabinet or a display, or starting the fan automatically after a period of time delay, and then entering a unit starting mode; in standby mode, the target pitch angle of the blade is θ_{b_max}；

Step 3, in the starting mode, the target pitch angle of the blade is theta_{b_t2}Target blade opening rate of w_{b_t2}The main control system sends a pre-charging command to the converter, then the main control system sends a network side starting command to perform network side modulation, and waits for machine side modulation; when the motor speed reaches n_{g_t2}And with a delay of T_delay2Then, the unit enters a pre-acceleration mode;

step 4, in the pre-acceleration mode, adjusting the target pitch angle of the blade to be theta_{b_t3}Target blade opening rate of w_{b_t3}When the motor speed reaches n_{g_t3}And after the wind error of the engine room is smaller than a set value, the delay T is carried out_delay3The unit enters an acceleration mode;

Step 5, in the acceleration mode, adjusting the target pitch angle of the blade to theta_{b_t4}Target blade opening rate of w_{b_t4}when the motor speed reaches n_{g_t4}And with a delay of T_delay4The unit enters a grid-connected mode;

Step 6, in a grid-connected mode, if the machine side is modulated, the main control system issues a target torque instruction to the converter for the first time, and the unit executes torque variable pitch combined control; when the wind speed gradually rises, the main control system sequentially passes through a maximum wind energy capture area, a constant rotating speed area and a constant power area, and respectively takes the maximum output of the unit to be maintained as a control target, the motor transfer area to be maintained constant as a control target and the output of the unit to be maintained at a rated power as a control target;

step 7, when the global shutdown level is greater than a set value, the unit immediately enters a shutdown mode; under a starting mode, a pre-accelerating mode, an accelerating mode and a grid-connected mode, if the global shutdown level is greater than a set value, entering a shutdown mode after delaying;

step 8, in the shutdown mode, when the blade of the unit reaches the maximum pitch angle, the unit enters a standby mode after delaying for a set time; in the standby mode, when the tower footing cabinet panel presses the service mode switch, the unit enters the service mode, and in the service mode, when the tower footing cabinet panel resets the service mode switch, the unit enters the shutdown mode.

3. The control method according to claim 2, characterized in that: the set value theta of the pitch angle_{b_max}、θ_{b_t2}、θ_{b_t3}、θ_{b_t4}Sequentially setting the target blade opening rate set value w of 88 degrees, 75 degrees, 40 degrees and 0 degrees_{b_t2}、w_{b_t3}、w_{b_t4}Sequentially comprises 2.5 degrees/s, 1.5 degrees/s, 1.1 degrees/s and a set value n of the rotating speed of the motor_{g_t2}、n_{g_t3}、n_{g_t4}this was followed by 0.2rpm, 1.2rpm and 6.5 rpm.

4. The control method according to claim 2, characterized in that: the delay time T_delay2、T_delay3、T_delay4The sequences were 15s, 20s, 0 s.

5. The control method according to claim 2, characterized in that: the starting process of the unit is as follows: after the self-checking of the master control system is completed, the unit is started, the master control system sends a pre-charging instruction to the converter, the direct-current bus is subjected to voltage building, the master breaker is subjected to network side modulation after being sucked, and then the master control system sends a starting position variable pitch target speed to the variable pitch system; in the process, when the rotating speed of the motor reaches a target value, the main control system sends a pre-acceleration position variable pitch target speed to the variable pitch system; in the process, when the rotating speed of the motor reaches a target value, the master control system sends an acceleration position variable pitch target speed to the variable pitch system; in the process, when the rotating speed of the motor reaches a target value, performing side modulation, then entering a grid-connected mode, issuing a grid-connected instruction to the converter by the main control system, transmitting a waiting torque instruction to the main control after the converter performs side modulation, issuing a target torque by the main control system, controlling the motor by the converter, performing grid-connected power generation on the unit, and ending the starting process.

6. The control method according to claim 5, characterized in that: when the unit enters a maximum wind energy capture area below a designed rated wind speed to operate, the calculation method of the target torque and the target power comprises the following steps:

(a) Establishing a fan operation simulation model, and determining boundary conditions and constraint conditions of the model;

(b) Solving the model, and simulating to obtain C between the wind energy utilization coefficient and the blade tip speed ratio_pLambda curve, obtaining maximum wind energy utilization coefficient C_pAnd corresponding optimum tip speed ratio lambda_opt；

(c) Establishing a target power function and a target torque function of the unit:

(d) Using the maximum wind energy utilization coefficient C obtained in step (b)_pAnd corresponding optimum tip speed ratio lambda_optAnd (c) substituting the target torque and the target power into the step (c), and then issuing the target torque and the target power to the converter.

7. The control method according to claim 2, characterized in that: the unit shutdown process is as follows: after the shutdown related event is triggered, if the unit is in a standby mode and the global shutdown level is not less than a set value, or the unit is in an operation mode and the global shutdown level is greater than the set value, calculating a target pitch-retracting angle in the period according to the set pitch-retracting rate and the task period, issuing a feathering rate instruction to a pitch-changing system according to the shutdown level, and executing a blade feathering process; and then the main control system issues a shutdown instruction to the converter, the converter stops modulation, the machine side disconnecting switch and the network side circuit breaker are disconnected, the unit calculates to give a decreasing target torque, when the rotating speed of the motor is reduced below a set critical value or the blade angle reaches a maximum set angle, the shutdown process is finished after a period of time delay, and the unit enters a standby mode.

8. The control method according to claim 2, characterized in that: in the process of grid-connected operation of the unit, if the rotating speed of the motor is reduced to a first-stage critical rotating speed value and lasts for a short set time, or the rotating speed of the motor is reduced to a second-stage critical rotating speed value and lasts for a long set time, activating a low-rotating-speed shutdown event; and if the rotating speed of the motor is reduced to a third-stage critical rotating speed value, immediately activating a low-rotating-speed shutdown event, and then executing a shutdown process.

Technical Field

The invention belongs to the technical field of control of wind turbines, and particularly relates to an automatic start-stop control method for a master control system of a permanent magnet direct-drive wind turbine generator.

Background

Wind energy is an important clean renewable energy source, wind power generation is a main form for developing and utilizing wind energy, a wind turbine generator is developed towards a high-capacity direction at present, and a permanent magnet direct-drive fan is a main installation form of a megawatt wind turbine generator. The wind turbine generator needs to operate for a long time under the unattended condition, the requirements on the safety and the reliability of a control system are high, and the design of the permanent magnet direct-drive type fan master control system meeting the actual operation requirements is of great significance.

At present, relevant research is carried out on the design and development of a permanent magnet direct drive type fan master control system at home and abroad, but some problems still exist. The cooperative control method among the state machine, the current transformer and the variable pitch system in the starting process of the unit is imperfect; the control parameter ranges of the state machines and the switching standards of the state machines at different load-increasing stages in the starting process of the unit have no obvious division boundary; meanwhile, the filtering processing method for important parameters such as the rotating speed of the motor proximity switch is simple.

in conclusion, the design optimization is carried out on the realization of automatic start and stop of the unit in the main control system, the cooperative control strategy of the state machine, the converter and the variable pitch system of the main control system in the start and grid connection process of the unit is formulated, the information of the field device is fully considered to determine the stop logic of the unit, and the research on the control method for realizing the variable pitch system in the stop process in a grading manner has very strong practical significance.

Disclosure of Invention

The invention aims to provide a control method for automatically starting and stopping a permanent magnet direct drive fan main control system unit, which can realize automatic starting and stopping of the unit under the unattended condition according to the external environment and the self condition of the unit, and the main control system, a converter and a variable pitch system are cooperatively controlled in the starting and stopping process to finally ensure the safe and stable operation of the unit.

In order to achieve the above purpose, the solution of the invention is:

A control method for automatically starting and stopping a unit of a permanent magnet direct-drive fan main control system is characterized in that a state machine switching method is used for realizing the control of the starting and stopping process of a fan, the unit has a corresponding control target in each mode when the unit reaches one mode in the starting process, and the unit enters the next state machine mode when the rotating speed of a motor, the pitch angle of a blade and the delay time reach set values.

Dividing the state of the unit in the process of starting, running and grid-connection into an initialization mode, a standby mode, a starting mode, a pre-acceleration mode, an acceleration mode, a grid-connection mode, a shutdown mode and a service mode, and switching the state machine mode of the unit according to the following steps:

step 1, a master control system carries out self-checking in an initialization mode, initializes system parameters and global variables, and enters a standby mode state after initialization is passed;

step 2, in the standby mode, when the global shutdown level and the global yaw level are both smaller than a set value, and the draught fan is in the maximum feathering angle state, the self-checking of the converter is completed; pressing a starting button on a tower footing cabinet or a display, or starting the fan automatically after a period of time delay, and then entering a unit starting mode; in standby mode, the target pitch angle of the blade is θ_{b_max}；

Step 3, in the starting mode, the target pitch angle of the blade is theta_{b_t2}target blade opening rate of w_{b_t2}the main control system sends a pre-charging command to the converter, then the main control system sends a network side starting command to perform network side modulation, and waits for machine side modulation; when the motor speed reaches n_{g_t2}And with a delay of T_delay2Then, the unit enters a pre-acceleration mode;

Step 4, in the pre-acceleration mode, adjusting the target pitch angle of the blade to be theta_{b_t3}Target blade opening rate of w_{b_t3}when the motor speed reaches n_{g_t3}And after the wind error of the engine room is smaller than a set value, the delay T is carried out_delay3the unit enters an acceleration mode;

step 5, in the acceleration mode, adjusting the target pitch angle of the blade to theta_{b_t4}target blade opening rate of w_{b_t4}When the motor speed reaches n_{g_t4}and with a delay of T_delay4The unit enters a grid-connected mode;

Step 6, in a grid-connected mode, if the machine side is modulated, the main control system issues a target torque instruction to the converter for the first time, and the unit executes torque variable pitch combined control; when the wind speed gradually rises, the main control system sequentially passes through a maximum wind energy capture area, a constant rotating speed area and a constant power area, and respectively takes the maximum output of the unit to be maintained as a control target, the motor transfer area to be maintained constant as a control target and the output of the unit to be maintained at a rated power as a control target;

step 7, when the global shutdown level is greater than a set value, the unit immediately enters a shutdown mode; under a starting mode, a pre-accelerating mode, an accelerating mode and a grid-connected mode, if the global shutdown level is greater than a set value, entering a shutdown mode after delaying;

Step 8, in the shutdown mode, when the blade of the unit reaches the maximum pitch angle, the unit enters a standby mode after delaying for a set time; in the standby mode, when the tower footing cabinet panel presses the service mode switch, the unit enters the service mode, and in the service mode, when the tower footing cabinet panel resets the service mode switch, the unit enters the shutdown mode.

Further, in a maximum wind energy capture area below the designed rated wind speed, the target power and the target torque are calculated in real time according to the optimal blade tip speed and the maximum wind energy utilization coefficient.

further, the system possesses the auto-stop function, its characterized in that:

And when the shutdown related event is triggered, entering a shutdown flow judgment process. In the standby mode, when the size of the global shutdown level meets the set condition, or in the starting, pre-accelerating, accelerating and grid-connected modes, when the size of the global shutdown level meets the set condition, the unit enters the shutdown mode after time delay. And after entering a shutdown mode, executing a shutdown flow judgment process. On one hand, the blade feathering speed is determined according to the global shutdown level, then the single feathering angle is calculated according to the task period, and finally the single feathering angle is sent to a pitch controller to execute the blade feathering process. On the other hand, the main control system gives a shutdown instruction to the converter, the converter stops modulation, and the machine side disconnecting switch and the network side circuit breaker are disconnected. The machine set calculates a decreasing target torque, when the rotating speed of the motor is reduced below a set value or the blade angle reaches a maximum set angle, the shutdown process is finished after a period of time delay, and the machine set enters a standby mode.

Further, in the process of grid-connected operation of the unit, when the wind speed in the natural world is low, if the rotating speed of the motor is reduced to a first-stage critical rotating speed value and lasts for a short set time, or if the rotating speed of the motor is reduced to a second-stage critical rotating speed value and lasts for a long set time, a low-rotating-speed shutdown event is activated, if the rotating speed of the motor is reduced to a third-stage critical rotating speed value, the low-rotating-speed shutdown event is immediately activated, and then a shutdown process is executed.

and further, the rotating speed of the impeller used in the fan control algorithm is determined by comprehensively considering the rotating speed of the motor proximity switch and the rotating speed calculated by the converter. When the rotating speed of the motor is high, the rotating speed of the impeller used by the algorithm of the controller is calculated by a converter; when the rotating speed of the motor is low, the rotating speed of the impeller used by the algorithm of the controller selects the rotating speed of the motor approach switch.

Particularly, the rotating speed measured by the motor proximity switch is a high-frequency signal, and the measured instantaneous rotating speed of the proximity switch is subjected to filtering processing so as to weaken the influence of high-frequency signal noise and interference in the instantaneous rotating speed on the rotating speed output to the controller.

After adopting the scheme, the invention has the following characteristics:

(1) the method comprises the steps that a state machine switching method is used for controlling the starting and stopping process of the fan, the state machine determines the target pitch angle and the opening speed of the blade, and the state machine jumps according to the rotating speed of the motor, the pitch angle of the blade and a delay interval;

(2) The method comprises the steps of determining a division boundary and a switching method of a machine set state machine, performing coordination control on a main control system, a converter and a variable pitch system in the switching process of the state machine, issuing control instructions to the converter and the variable pitch system by the main control system to realize coordination control, calculating target power and target torque in real time according to the optimal blade tip speed and the maximum wind energy utilization coefficient in a maximum wind energy capture area below a designed rated wind speed, issuing target torque and power factor instructions to the converter in real time to realize control over a motor by the main control system, and issuing target blade angle instructions to a variable pitch controller in real time to realize control over an impeller. Determining the feathering rate according to the global shutdown level in the shutdown process to realize graded shutdown;

(3) filtering the rotating speed of the motor proximity switch by adopting a recursive average sliding window method, and determining the rotating speed of the motor used by a control algorithm after comprehensively considering the rotating speed calculated by the converter and the rotating speed of the motor proximity switch;

(4) The invention is stable and reliable, is easy to realize and deploy, and has easy operability and practicability.

Drawings

FIG. 1 is a system state machine switching flow diagram;

FIG. 2 is a block diagram of a unit start-up process flow diagram;

FIG. 3 is a block diagram of a unit shutdown process;

FIG. 4 is a flow chart of a motor proximity switch speed filtering method.

Detailed Description

The technical solution and the advantages of the present invention will be described in detail with reference to the accompanying drawings.

As shown in fig. 1, the invention provides a control method for automatically starting and stopping a permanent magnet direct drive fan main control system unit, which uses a state machine to switch to realize the control of the starting and stopping process of a fan, and divides the state of the unit in the starting, running and Grid-connection process into an Initialization mode (Initialization), a Standby mode (Standby), a starting mode (starting), a Pre-Acceleration mode (Pre _ Acceleration), an Acceleration mode (Acceleration), a Grid-Connected mode (Grid _ Connected), a Shutdown mode (Shutdown), and a Service mode (Service). When the motor speed, the blade pitch angle and the delay time reach set values, the unit enters the next state machine mode.

In this embodiment, a self-starting model of a main control system of a 2MW permanent-magnet direct-drive fan is established to control related parameters. The main performance parameters of the fan are as follows: the rated power of the wind generating set is 2000kW, the basic structure type adopts a three-blade wind direction, the diameter of an impeller is 121.6m, the height of a hub is 90m, the cut-in wind speed is 2.5m/s, the rated wind speed is 8.6m/s, and the cut-out wind speed is 22 m/s. The optimum tip speed ratio is 10 and the torque coefficient is 671083. The rated capacity of the converter is 2990kVA, the phase number is 3P + PE, the machine side voltage is 0-690VAC, the machine side current is 2500A, the machine side frequency is 0-50Hz, the network side voltage is 690VAC, and the network side current is 2500A.

the switching operation of the group state machine mode is performed using the steps shown in fig. 1:

(1) In step 101, the main control system performs self-checking in an initialization mode, initializes system parameters and global variables, and enters a standby mode state in step 102 after initialization is passed;

(2) and a carrying step 102, in a standby mode, when the global shutdown level and the global yaw level are both smaller than a set value, and the draught fan is in a maximum feathering angle state, the self-inspection of the converter is completed. And pressing a start button on the tower footing cabinet or the display, or stopping the fan for a period of time and then starting the fan for the time, and then entering a unit start mode in step 103. In standby mode, the target pitch angle of the blade is θ_{b_max}namely, the maximum pitch angle reached by the feathering of the blades after the machine set is shut down is kept unchanged;

(3) in a receiving step 103, in the start mode, the target pitch angle of the blade is θ_{b_t2}Target blade opening rate of w_{b_t2}and the main control system sends a pre-charging command to the converter, builds the voltage of the direct-current bus, closes the main breaker, sends a network side starting command to perform network side modulation and waits for the machine side modulation. At the moment, the blade retracts, the mechanical torque borne by the blade is increased, the motor accelerates, and when the rotating speed of the motor reaches n_{g_t2}And with a delay of T_delay2then, step 104 is carried out, and the unit enters a pre-acceleration mode;

(4) A step 104 of adjusting the target pitch angle of the blade to θ in the pre-acceleration mode_{b_t3}Target blade opening rate of w_{b_t3}at this time, the blade continues to be retractedThe mechanical torque applied to the sheet is increased, the rotating speed of the motor is continuously increased, and when the rotating speed of the motor reaches n_{g_t3}And after the wind error of the engine room is smaller than a set value, the delay T is carried out_delay3step 105 is entered, the unit enters an acceleration mode;

(5) A step 105 of adjusting the target pitch angle of the blade to θ in the acceleration mode_{b_t4}Target blade opening rate of w_{b_t4}At the moment, the blades continue to retract, the mechanical torque borne by the blades is increased, the motor continues to accelerate, and when the rotating speed of the motor reaches n_{g_t4}And with a delay of T_delay4Step 106 is entered, and the unit enters a grid-connected mode;

(6) And 106, in a grid-connected mode, if the machine side is modulated, the main control system issues a target torque instruction to the converter for the first time, and the unit executes the torque variable pitch combined control. When the wind speed gradually rises, the main control system sequentially passes through a maximum wind energy capture area, a constant rotating speed area and a constant power area, and respectively takes the maximum output of the unit to be maintained as a control target, the motor transfer area to be maintained constant as a control target and the output of the unit to be maintained at a rated power as a control target;

(7) In the standby mode of step 102, when the global shutdown level is greater than the set value, the unit immediately enters the shutdown mode of step 107. In the step 103 starting mode, the step 104 pre-accelerating mode, the step 105 accelerating mode and the step 106 grid-connected mode, if the global shutdown level is greater than a set value, the step 107 shutdown mode is entered after time delay;

(8) in the stop mode of step 107, the target torque issued by the main controller is rapidly reduced, different feathering rates are set according to different global stop levels to enable the blades to feather, and the rotating speed of the motor is reduced. And when the rotating speed of the motor is reduced to a set value, the master control issues a network side modulation stopping instruction to the converter, and the converter stops modulation. In the shutdown mode, entering a standby mode in step 102 after a set time delay after the blades of the unit reach the maximum pitch angle;

(9) In the standby mode of step 102, when the tower base cabinet panel presses the service mode switch, the unit enters the service mode of step 108. In step 108, in the service mode, when the tower base cabinet panel resets the service mode switch, the shutdown mode is entered in step 107. In the service mode, at step 108, equipment servicing, maintenance, etc. operations may be performed.

During the state code switching process, the set value theta of the pitch angle_{b_max}、θ_{b_t2}、θ_{b_t3}、θ_{b_t4}Target blade opening rate setpoint w_{b_t2}、w_{b_t3}、w_{b_t4}the motor speed is set to a value n_{g_t2}、n_{g_t3}、n_{g_t4}Time delay T_delay2、T_delay3、T_delay4And the constant value is selected and determined according to the design requirement of the fan. The pitch angles determined in this embodiment are 88 °, 75 °, 40 °, and 0 ° in this order, the target blade opening rate setting values are 2.5 °/s, 1.5 °/s, and 1.1 °/s in this order, the motor rotation speed setting values are 0.2rpm, 1.2rpm, and 6.5rpm in this order, and the delay times are 15s, 20s, and 0s in this order.

In the starting process of the fan, the master control system implements the issuing of the control command and the collecting of the state feedback with the variable pitch system and the converter, so as to realize the cooperative control, which is described in detail with reference to fig. 2 as follows:

After the self-checking of the main control system is completed in step 201, the unit is started and enters step 202, in step 202, the main control system sends a pre-charging command to the converter, the direct-current bus is subjected to voltage building, after the main breaker is closed, the unit enters step 203 for network side modulation, and then the unit enters step 204. In the accepting step 204, the master control system sends the target pitch rate of the starting position to the pitch system, and the execution is performed in step 212. In the process, after the rotating speed of the motor reaches the target value in step 205, the main control system sends a pre-acceleration position pitch target speed to the pitch system in step 206, and the step 213 executes the pre-acceleration position pitch target speed. In the process, after the rotating speed of the motor reaches the target value in step 207, the main control system sends the target speed of the pitch change of the acceleration position to the pitch change system in step 208, and the step 214 is executed. In the process, after the rotating speed of the motor reaches a target value in step 209, the machine side modulation in step 210 is performed, then the grid-connected mode in step 211 is performed, the main control system issues a grid-connected instruction to the converter, the converter performs the machine side modulation and then sends a waiting torque instruction to the main control, the main control system issues a target torque, the converter controls the motor, the unit is connected to the grid for power generation, and the starting process is finished.

when the unit enters a maximum wind energy capture area below a designed rated wind speed to operate, the calculation method of the target torque and the target power comprises the following steps:

(a) establishing a fan operation simulation model, and determining boundary conditions and constraint conditions of the model.

(b) solving the model, and simulating to obtain C between the wind energy utilization coefficient and the blade tip speed ratio_pLambda curve, obtaining maximum wind energy utilization coefficient C_pand corresponding optimum tip speed ratio lambda_opt。

(c) Establishing a target power function and a target torque function of the unit:

(d) The maximum wind energy utilization factor C determined in the step (a)_pAnd corresponding optimum tip speed ratio lambda_optSubstituting the target torque and the target power into the step (c), and then issuing the target torque and the target power to the converter.

Preferably, the simulation model in step (a) is created by using Bladed software.

The preferred tip speed ratio determined in this embodiment is 10 and the torque coefficient is 671083.

The unit shutdown process is executed according to the method shown in fig. 3, in step 301, after the status code shutdown event is triggered, if the unit is in the standby mode and the global shutdown level is not less than the set value in step 302, or if the unit is in the running mode and the global shutdown level is greater than the set value in step 303, the process proceeds to step 304 after a delay. In the connection step 304, the pitch angle of the target in the period is calculated according to the set pitch-retracting rate and the task period of the program, a feathering rate instruction is issued to the pitch control system according to the shutdown level, the step 309 is executed, and the blades are feathered in the step 309. The main control system then issues a shutdown command to the converter in step 305, and the converter stops modulating, the machine side disconnector and the grid side breaker open, executed by step 310. In step 306, the unit calculates a decreasing target torque, in step 307, after the motor speed is reduced below a set critical value or the blade angle reaches a maximum set angle, the shutdown process is finished after a time delay, in step 308, the unit enters a standby mode.

Further, in the process of grid-connected operation of the unit, when the wind speed in the natural world is low, if the rotating speed of the motor is reduced to a first-stage critical rotating speed value and lasts for a short set time, or if the rotating speed of the motor is reduced to a second-stage critical rotating speed value and lasts for a long set time, a low-rotating-speed shutdown event is activated, if the rotating speed of the motor is reduced to a third-stage critical rotating speed value, the low-rotating-speed shutdown event is immediately activated, and then a shutdown process is executed. The rotation speed critical value and the time delay determined by the embodiment are as follows: and when the rotating speed of the motor is reduced to the first-stage critical value 6.5rpm of the state code and lasts for 15min, or when the rotating speed of the motor is reduced to the second-stage critical value 6.3 and lasts for 3min, activating a low-rotating-speed automatic stop Event in the Event state code to execute a stop process. And immediately activating a low-speed automatic stop Event in the Event status code to execute a stop process after the rotating speed of the motor is reduced to a third-stage critical value of 4.7 rpm.

and determining the impeller rotating speed used in the fan control algorithm by comprehensively considering the motor proximity switch rotating speed and the converter calculated rotating speed. When the impeller rotating speed is high, compared with the rotating speed of a motor proximity switch, the rotating speed value calculated by the converter is accurate. When the rotating speed of the motor is high, the rotating speed of the impeller used by the algorithm of the controller is calculated by a converter; when the rotating speed of the motor is low, the rotating speed of the impeller used by the algorithm of the controller selects the rotating speed of the motor approach switch.

the rotating speed measured by the motor proximity switch is a high-frequency signal, and a recursive average sliding window method is adopted for filtering the measured instantaneous rotating speed of the proximity switch so as to weaken the influence of high-frequency signal noise and interference in the instantaneous rotating speed on the rotating speed output to the controller, and the filtering method for the rotating speed of the motor proximity switch shown in fig. 4 is described as follows:

In step 401, initializing parameters including the total length of the sliding buffer window and the length of the sliding window, the push address Insert _ Pos and the push address Remove _ Pos, then entering step 402, and when detecting that the kth instant rotating speed of the proximity switch arrives, entering step 403, and placing new data in the push address Insert _ Pos of the sliding buffer window. Step 404 is then entered where the updated pop position Insert _ Pos is incremented by 1. Step 405 is entered, and after the sliding window length is updated, step 406 is entered. And step 406, if the length of the sliding window is smaller than the set value, step 407 is entered, the average value of the rotation speeds is calculated after the current new data is accumulated, and step 409 is entered to output the filtered rotation speed. And step 406, if the Length of the sliding window is greater than the set value, accumulating the average value of the rotating speeds of the motors between the pop-up address of the buffer window and the pop-up position in step 410, outputting, and simultaneously increasing the Remove _ Pos by 1, and if the Remove _ Pos is greater than Win _ Length, taking the total Length of the window left by the Remove _ Pos as a new value of the Remove _ Pos and updating the IRemove _ Pos. After the pop position is updated in step 411, the current input data is accumulated in step 412, and then the filtered rotation speed average is calculated and output in step 413. And repeating the steps, and calculating the filtered rotating speed when the new rotating speed arrives at the next period.

the master control system is developed based on PLC hardware, controller hardware is respectively arranged in a cabin cabinet and a tower footing cabinet, and the master control system issues control instructions to related automation equipment by adopting hard wiring.

the above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.