Tham khảo tài liệu 'wind energy management part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 4 Wind Energy Management And the probability function is given by xk-1 k I v I cl c 0 v c k f - dsr dv exp 2 The average wind speed can be expressed as 0 J v f vf v dv f v 0 v k-1 exp - v k . c c . dv 3 Let v k c 1 xk - and c dx v k 1 dv c c Equation 3 can be simplified as 1 v cfxk exp -x dx 0 4 By substituting a Gamma Function X . . . 1 . r n f e xxn kdx into 4 and let y 1 then we have - . 1 v cr 1 4 I k 5 The standard deviation of wind speed v is given by . Use s f v - v 2 f v dv V 0 s f v2 2 vv v2 f v dv 0 J f v2 f v dv 2 v f vf v dv v 0 0 l f v2 f v dv 2 v V 0 6 7 Weibull Distribution for Estimating the Parameters 5 1 2 J 2 òv2f v dv òv2 k-1 dv Òc2xk k-1 dv òc2xk exp -x dx 8 J d c c d c c d 0 0 0 0 And put y 1 k then the following equation can be obtained 2 ò v2 f v dv c 2r 1 k 9 Hence we get 1 _ 2p 1 -I-1 2 c r 1 k -c r 1 k c r 1 2 r2 1 1 V k k 10 Linear Least Square Method LLSM Least square method is used to calculate the parameter s in a formula when modeling an experiment of a phenomenon and it can give an estimation of the parameters. When using least square method the sum of the squares of the deviations S which is defined as below should be minimized. S z wi yi g xi 11 i 1 In the equation xi is the wind speed yi is the probability of the wind speed rank so xi yi mean the data plot wi is a weight value of the plot and n is a number of the data plot. The estimation technique we shall discuss is known as the Linear Least Square Method LLSM which is a computational approach to fitting a mathematical or statistical model to data. It is so commonly applied in engineering and mathematics problem that is often not thought of as an estimation problem. The linear least square method LLSM is a special case for the least square method with a formula which consists of some linear functions and it is easy to use. And in the more special case that the formula is line the linear least square method is much easier. The Weibull distribution function is a .
