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A pitch control apparatus for controlling the pitch value for a wind power generation system includes a generator comparing unit that calculates an error signal based on a difference between a generator measurement signal corresponding with an operation of the power generation system and a generator

A pitch control apparatus for controlling the pitch value for a wind power generation system includes a generator comparing unit that calculates an error signal based on a difference between a generator measurement signal corresponding with an operation of the power generation system and a generator reference signal, and a reference pitch calculating unit that calculates a reference pitch value using the error signal. The pitch control apparatus further includes a compensation pitch calculating unit that calculates a compensation pitch value using an error value from the wind power generation system and a pitch calculating unit that calculates a pitch value using the reference pitch value and the compensation pitch value. The error value may be any one of a voltage error value from a direct-current capacitor, a voltage error value from a grid connection point, a speed error value from a rotor, and a frequency error value from a grid connection point.

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We claim: 1. A pitch control apparatus for controlling a pitch value in a wind power generation system, the pitch control apparatus comprising: a generator comparing unit configured to calculate an error signal based on a difference between a generator measurement signal and a generator reference s

We claim: 1. A pitch control apparatus for controlling a pitch value in a wind power generation system, the pitch control apparatus comprising: a generator comparing unit configured to calculate an error signal based on a difference between a generator measurement signal and a generator reference signal, the generator measurement signal corresponding with an operation of the power generation system; a reference pitch calculating unit configured to calculate a reference pitch value using the error signal; a compensation pitch calculating unit configured to calculate a compensation pitch value using an error value from the wind power generation system; and a pitch calculating unit configured to calculate a pitch value using the reference pitch value and the compensation pitch value, wherein the error value is any one of a voltage error value from a direct-current capacitor included in a power converter unit of the wind power generation system, a voltage error value from a grid connection point of the wind power generation system, a speed error value from a rotor of the wind power generation system, and a frequency error value from a grid connection point of the wind power generation system. 2. The pitch control apparatus of claim 1, wherein the generator measurement signal is a measurement signal relating to a rotation speed of a generator drive shaft or to a generator output, and the generator reference signal is a reference signal predefined in correspondence with the generator measurement signal. 3. The pitch control apparatus of claim 1, wherein the voltage error value is calculated based on a difference between a voltage measured at a direct-current capacitor included in a power converter unit of the wind power generation system and a reference voltage predefined in correspondence with the measured voltage, or is calculated based on a difference between a voltage measured at a grid connection point of the wind power generation system and a reference voltage predefined in correspondence with the measured voltage. 4. The pitch control apparatus of claim 1, wherein the frequency error value is calculated based on a difference between a measurement frequency measured at a grid connection point of the wind power generation system and a reference frequency predefined in correspondence with the measurement frequency. 5. The pitch control apparatus of claim 1, wherein the speed error value is calculated based on a difference between a measurement speed measured at a rotor of the wind power generation system and a reference speed predefined in correspondence with the measurement speed. 6. The pitch control apparatus of claim 1, wherein the compensation pitch calculating unit comprises: a compensation real power calculator configured to calculate a compensation real power value by using the voltage error value; and a compensation pitch calculator configured to calculate a compensation pitch value by using the compensation real power value. 7. The pitch control apparatus of claim 1, wherein the compensation pitch calculating unit comprises: a compensation real power calculator configured to calculate a compensation real power value by using the frequency error value; and a compensation pitch calculator configured to calculate a compensation pitch value by using the compensation real power value. 8. The pitch control apparatus of claim 1, wherein the compensation pitch calculating unit comprises: a compensation real power calculator configured to calculate a compensation real power value by using the speed error value; and a compensation pitch calculator configured to calculate a compensation pitch value by using the compensation real power value. 9. The pitch control apparatus of claim 6, wherein the compensation pitch calculating unit further comprises: a comparer configured to calculate the voltage error value; and an error limiter configured to modify the voltage error value to a tolerable voltage error value within a predefined voltage range, if the voltage error value is outside the predefined voltage range. 10. The pitch control apparatus of claim 7, wherein the compensation pitch calculating unit further comprises: a comparer configured to calculate the frequency error value; and an error limiter configured to modify the frequency error value to a tolerable frequency error value within a predefined frequency range, if the frequency error value is outside the predefined frequency range. 11. The pitch control apparatus of claim 8, wherein the compensation pitch calculating unit further comprises: a comparer configured to calculate the speed error value; and an error limiter configured to modify the speed error value to a tolerable speed error value within a predefined speed range, if the speed error value is outside the predefined speed range. 12. A pitch control system for controlling pitch values in a plurality of wind power generation systems, the pitch control system comprising: a plurality of pitch control apparatuses; and a compensation pitch calculating apparatus configured to calculate an apportion-compensation pitch value by using a voltage error value or a frequency error value calculated at a grid connection point where the plurality of wind power generation systems are connected, wherein the pitch control apparatus comprises: a generator comparing unit configured to calculate an error signal based on a difference between a generator measurement signal and a generator reference signal, the generator measurement signal corresponding with an operation of the power generation system; a reference pitch calculating unit configured to calculate a reference pitch value by using the error signal; and a pitch calculating unit configured to calculate a pitch value by using the reference pitch value and the apportion-compensation pitch value calculated by the compensation pitch calculating apparatus. 13. The pitch control system of claim 12, wherein the generator measurement signal is a measurement signal relating to a rotation speed of a generator drive shaft or to a generator output, and the generator reference signal is a reference signal predefined in correspondence with the generator measurement signal. 14. The pitch control system of claim 12, wherein the voltage error value is calculated based on a difference between a voltage measured at a grid connection point of the wind power generation system and a reference voltage predefined in correspondence with the measured voltage. 15. The pitch control system of claim 12, wherein the frequency error value is calculated based on a difference between a measurement frequency measured at a grid connection point of the wind power generation system and a reference frequency predefined in correspondence with the measurement frequency. 16. The pitch control system of claim 12, wherein the compensation pitch calculating apparatus comprises: a compensation pitch calculating unit configured to calculate a compensation pitch value by using the voltage error value or the frequency error value; and an apportion-compensation pitch calculating unit configured to calculate a plurality of apportion-compensation pitch values for applying to the pitch control apparatuses by using the compensation pitch value and a predefined pitch limit value. 17. The pitch control system of claim 16, wherein the apportion-compensation pitch calculating unit comprises: a compensation pitch apportioner configured to calculate a plurality of first apportion-compensation pitch values by apportioning the compensation pitch value; and an apportion-compensation pitch calculator configured to calculate a plurality of second apportion-compensation pitch values for applying to the pitch control apparatuses by using the plurality of first apportion-compensation pitch values and a predefined pitch limit value. 18. The pitch control system of claim 17, wherein the apportion-compensation pitch calculating unit passes the first apportion-compensation pitch values included within the pitch limit values to calculate the second apportion-compensation pitch values. 19. The pitch control system of claim 16, wherein the compensation pitch calculating apparatus further comprises: a comparing unit configured to calculate the voltage error value or the frequency error value; and an error limiting unit configured to modify the voltage error value or the frequency error value to a tolerable voltage error value within a predefined voltage range or a tolerable frequency error value within a predefined frequency range, respectively, if the voltage error value or frequency error value is outside the predefined voltage range or predetermined frequency range, respectively. 20. The pitch control system of claim 16, wherein the compensation pitch calculating apparatus further comprises: a compensation pitch comparing unit configured to calculate a deviation signal by using a sum of first apportion-compensation pitch values and a sum of second apportion-compensation pitch values; and an anti-windup unit configured to prevent windup in the compensation pitch calculating unit by using the deviation signal and the voltage error value or the frequency error value. 21. The pitch control system of claim 20, wherein the anti-windup unit inputs to the compensation pitch calculating unit a sum of the deviation signal, multiplied by a tracking time constant (kt), and the voltage error value or the frequency error value. 22. The pitch control system of claim 17, comprising a j number of wind power generation systems, j being a natural number, wherein a j number of pitch control apparatuses are connected to the wind power generation systems respectively, and the second apportion-compensation pitch values are calculated according to the following equation: U j , s set = min ⁢ { U max , P j , c ∑ n = 1 j ⁢ ⁢ P n , c ⁢ U } wherein Usetj,s is an apportion-compensation pitch value as a control signal provided to a jth pitch control apparatus by an apportion-compensation pitch calculating unit of a compensation pitch calculating apparatus, Pj,c is a real power value of a jth unit wind power generation system, ∑ n = 1 j ⁢ ⁢ P n , c is a sum of real power values from a first to the jth unit wind power generation systems, and Umax is a pitch limit value, and wherein min{a,b} represents a smaller value between a and b, a subscript j is a natural number 1, 2, 3, . . . , n representing a number of a pitch control apparatus, and a superscript max represents a maximum value.