Pitch control method and system of symmetrical-airfoil vertical axis wind turbine

Patent metadata

Field	Value
Publication number	US-11549489-B2
Application number	US-202117334260-A
Country	US
Kind code	B2
Filing date	May 28, 2021
Priority date	Jun 1, 2020
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

A pitch control method and system of a symmetrical-airfoil vertical axis wind turbine collects data by an anemometer, an anemoscope and an angle sensor, outputs an optimum pitch angle based on a control law of a pitch angle and controls the pitch angle to be the optimum pitch angle through a pitch control actuator. In addition to input variables of the control law such as a wind velocity vin and a blade azimuth angle Ψ, constants such as a rotation radius R, a rotation velocity Ω of the blade and aerodynamic coefficients c1, c2 and c3 are also related. A Reynolds number has little influence on three aerodynamic coefficients c1, c2 and c3. The pitch actuator controls the adjustment rods to realize the automatic pitch control of the blades. An expression of the control law of the pitch is concise, the calculation time is short, and a response speed is fast.

First claim

What is claimed is:

1. A method to control pitch of symmetrical-airfoil blades of a vertical axis wind turbine, the method comprising:
collecting, by an anemometer communicatively connected to a controller of the vertical axis wind turbine, wind velocity data;
collecting, by an anemoscope communicatively connected to the controller, wind direction data;
collecting, by an angle sensor communicatively connected to the controller, rotation data of the blades;
transmitting, by the anemometer, the wind velocity data to the controller;
transmitting, by the anemoscope, the wind direction data to the controller;
transmitting, by the angle sensor, the blade rotation data to the controller;
determining, by the controller, an optimum pitch angle for the blades, such that

θ
p

=

Γ
-

2
⁢

⁢

c
2

-

4
⁢

⁢

c
2
2

-

12
⁢

⁢

c
1

⁢

c
3

⁢

tan
2

⁢
Γ

6
⁢

⁢

c
3

⁢
tan
⁢

⁢
Γ

⁢

;

wherein θ p is the optimal pitch angle,

Γ
=

arctan
⁢

⁢

cos
⁢

⁢
Ψ

sin
⁢

⁢
Ψ

-
λ

,

 is a blade azimuth angle of a respective one of the blades with respect to a rotational direction of the vertical axis wind turbine, the blade azimuth angle being determined based on the data from the anemoscope and the angle sensor,

λ
=

R
⁢
Ω

v
in

 is a tip speed ratio, where R is a rotation radius of the blades, Ω is a rotation velocity of the blades, and v in is the wind velocity,
wherein c 1 , c 2 , and c 3 , are aerodynamic coefficients in a lift coefficient expression C L (α)=c 1 α+c 3 α 3 and a drag coefficient expression C D (α)=c 0 +c 2 α 2 ; α is an attack angle, which represents an angle between a relative wind velocity v r and an airfoil chord line, where v r =v in −RΩ;

transmitting, by the controller, the determined optimal pitch angle to a pitch actuator; and
controlling, by the pitch actuator, pitch of the blades based on the received optimal pitch angle.

2. A pitch control system of a symmetrical-airfoil vertical axis wind turbine, comprising:
a controller;
a rotation shaft arranged vertically;
a plurality of symmetrical blades;
a plurality of connecting rods, one of two ends of each connecting rod being connected with one of the plurality of symmetrical blades, wherein the other one of the two ends of each connecting rod is connected to the rotation shaft;
a pitch actuator that is provided with adjustment rods connected to the blades and is in communication connection with the controller;
an angle sensor in communication connection with the controller;
an anemoscope that collects wind direction data and is in communication connection with the controller; and
an anemometer that collects wind velocity data and is in communication connection with the controller;
wherein the controller outputs an optimal pitch angle based on the data collected by the anemoscope and the anemometer, the optimal pitch angle controlled by the pitch actuator being determined by:

θ
p

=

Γ
-

2
⁢

⁢

c
2

-

4
⁢

⁢

c
2
2

-

12
⁢

Assignees

• Univ Anhui Sci & Technology

Inventors

• Li Liang
• Jing Laiwang
• Wu Jianqiang
• Wang Long
• Miao Guanghong

Classifications

• F03D7/0204

  for orientation in relation to wind direction · CPC title

• F05B2200/13

  Product · CPC title

• F05B2270/328

  Blade pitch angle · CPC title

• Y02E10/74

  Wind turbines with rotation axis perpendicular to the wind direction · CPC title

• F05B2200/261

  Sine · CPC title