Control method for inhibiting input electric network power fluctuation in wind power generation system

Abstract

The invention relates to the field of a wind power generation system, and discloses particularly a controlling means to restrain the power fluctuation of an input power network in the wind power generation system. Based on the wind power generation system provided with a convertor and a DC side capacitor, a method of the invention has the control steps as follows: in step one, the input power Pin of the DC side capacitor is calculated; in step two, the output power Pout of the DC side capacitor is calculated; in step three, the calculated value udcj of DC side capacitor voltage is evaluated; in step four, the calculated value udcj of the DC side capacitor voltage is used as a voltage instruction value to control a PWM inverter, and when the DC side capacitor voltage udc is 85 percent to 110 percent of the voltage rating of the DC side capacitor, the power fluctuation of the input power network can be restrained. The invention utilizes the energy-stored effect of the DC side capacitor to restrain the output power fluctuation caused by the power fluctuation corresponding to wind energy through properly adjusting the DC side voltage, no extra auxiliary devices are needed, and the controlling means can be widely used in the wind power generation system.

Description

technical field [0001] The invention relates to the field of wind power generation systems, in particular to a control method for suppressing power fluctuations in an input grid, in particular to a control method for suppressing power fluctuations by utilizing DC side capacitance. Background technique [0002] In recent years, with the continuous aggravation of energy crisis and environmental problems, governments of various countries have focused on energy exploration. Wind energy in renewable energy has attracted much attention because of its large reserves, no pollution, and tending to industrialization. The cost and cost of wind power system itself are relatively high, so wind farm operators are pursuing the maximum utilization of wind energy to improve the utilization rate of the system. At the same time, the wind itself is random and variable, and the wind energy is proportional to the cube of the wind speed. When the wind speed changes sharply, the wind energy change...

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Problems solved by technology

Moreover, the method proposed in this paper only absorbs power fluctuations within a specific frequency range. While reducing the capacity of the capacitive energy storage system, it also reduces the effect of suppressing power fluctuations in the wind power generation system.

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