A method of controlling a switching frequency of a wind power converter, comprising: obtaining a modulation voltage of a generator-side converter; adjusting an amplitude of the modulation voltage in k consecutive switching cycles; generating a PWM pulse signal according to the adjusted modulation voltage, wherein a frequency of the generated PWM pulse signal is 1/k of a frequency of a first PWM pulse signal, k is an integer equal to or greater than 2, and the frequency of the first PWM pulse signal represents a frequency of a PWM pulse signal generated when the modulation voltage is not adjusted; and generating a control signal of the generator-side converter according to the PWM pulse signal; wherein adjusting the amplitude of the modulation voltage in the k consecutive switching cycles comprises: when 0<U x ≤1/k, U x * =kU x, N=1, 2; and U x * =0, N=3,..., 2k; when(m-1)/k<U x ≤m/k, U x * =kU x -m+1, N=1; U x * =1, N=2,..., 2m-1; U x * =kU x -m+1, N=2m; and U x * =0, N=2m+1,..., 2k; and when (k-1)/k<U x <1, U x * =kU x -k+1, N=1; and U x * =1, N=2,..., 2k-1, wherein U x is the modulation voltage, U x * is the adjusted modulation voltage, m is an integer greater than 1 and less than k, and N represents a half-switching cycle in the consecutive switching cycles, N is a natural number, a value of which is taken from 2k consecutive half-switching cycles, wherein, for example, N=1 represents the first half-switching cycle in the two consecutive switching cycles, and so on; wherein the method further comprises: obtaining an operating rotating-speed of a wind power generator; and determining whether a difference between the operating rotating-speed and a synchronous rotating-speed is less than or equal to a predetermined threshold, and adjusting the amplitude of the modulation voltage in the k consecutive switching cycles if the difference is less than or equal to the predetermined threshold, and not adjusting the modulation voltage if the difference is greater than the predetermined threshold. obtaining a modulation voltage of a generator-side converter; adjusting an amplitude of the modulation voltage in k consecutive switching cycles; generating a PWM pulse signal according to the adjusted modulation voltage, wherein a frequency of the generated PWM pulse signal is 1/k of a frequency of a first PWM pulse signal, k is an integer equal to or greater than 2, and the frequency of the first PWM pulse signal represents a frequency of a PWM pulse signal generated when the modulation voltage is not adjusted; and generating a control signal of the generator-side converter according to the PWM pulse signal; wherein adjusting the amplitude of the modulation voltage in the k consecutive switching cycles comprises: when 0<U x ≤1/k, U x * =kU x, N=1, 2; and U x * =0, N=3,..., 2k; when(m-1)/k<U x ≤m/k, U x * =kU x -m+1, N=1; U x * =1, N=2,..., 2m-1; U x * =kU x -m+1, N=2m; and U x * =0, N=2m+1,..., 2k; and when (k-1)/k<U x <1, U x * =kU x -k+1, N=1; and U x * =1, N=2,..., 2k-1, wherein U x is the modulation voltage, U x * is the adjusted modulation voltage, m is an integer greater than 1 and less than k, and N represents a half-switching cycle in the consecutive switching cycles, N is a natural number, a value of which is taken from 2k consecutive half-switching cycles, wherein, for example, N=1 represents the first half-switching cycle in the two consecutive switching cycles, and so on; wherein the method further comprises: obtaining an operating rotating-speed of a wind power generator; and determining whether a difference between the operating rotating-speed and a synchronous rotating-speed is less than or equal to a predetermined threshold, and adjusting the amplitude of the modulation voltage in the k consecutive switching cycles if the difference is less than or equal to the predetermined threshold, and not adjusting the modulation voltage if the difference is greater than the predetermined threshold. when 0<U x ≤1/k, U x * =kU x, N=1, 2; and U x * =0, N=3,..., 2k; when(m-1)/k<U x ≤m/k, U x * =kU x -m+1, N=1; U x * =1, N=2,..., 2m-1; U x * =kU x -m+1, N=2m; and U x * =0, N=2m+1,..., 2k; and when (k-1)/k<U x <1, U x * =kU x -k+1, N=1; and U x * =1, N=2,..., 2k-1, wherein U x is the modulation voltage, U x * is the adjusted modulation voltage, m is an integer greater than 1 and less than k, and N represents a half-switching cycle in the consecutive switching cycles, N is a natural number, a value of which is taken from 2k consecutive half-switching cycles, wherein, for example, N=1 represents the first half-switching cycle in the two consecutive switching cycles, and so on; wherein the method further comprises: obtaining an operating rotating-speed of a wind power generator; and determining whether a difference between the operating rotating-speed and a synchronous rotating-speed is less than or equal to a predetermined threshold, and adjusting the amplitude of the modulation voltage in the k consecutive switching cycles if the difference is less than or equal to the predetermined threshold, and not adjusting the modulation voltage if the difference is greater than the predetermined threshold. obtaining an operating rotating-speed of a wind power generator; and determining whether a difference between the operating rotating-speed and a synchronous rotating-speed is less than or equal to a predetermined threshold, and adjusting the amplitude of the modulation voltage in the k consecutive switching cycles if the difference is less than or equal to the predetermined threshold, and not adjusting the modulation voltage if the difference is greater than the predetermined threshold.