Double-fed type wind generating set low-voltage-ride-through control method based on electromagnetic transient algorithm

Abstract

The invention discloses a double-fed type wind generating set low-voltage-ride-through control method based on an electromagnetic transient algorithm. The double-fed type wind generating set low-voltage-ride-through control method is characterized in that when falling fault happens to power grid voltages, a control system controls double-fed motor stator flux linkage decoupling, transient state compensating current computing and composition and rotor current loop closing, so that a low-voltage-ride-through purpose of a double-fed type wind generating set is achieved. According to the requirement that transient state voltage impact at a double-fed motor rotor end is lowered when a power grid falls, transient state compensating currents are injected into the double-fed motor rotor end, the angle of the double-fed motor rotor end is set, so that the transient state voltages at the rotor end is optimally controlled when the power grid voltages fall, and accordingly impact from the transient state voltages on the double-fed type wind generating set when the voltages fall is lowered, and meanwhile decay speed of stator direct current flux linkage can be increased, a transient state process of a system is shortened, and influence from a flux linkage negative sequence component on the wind generating set is lowered. Accordingly, through the low-cost high-reliability control method, the voltage fault range which the double-fed type wind generating set can ride through is expanded, and the low-voltage-ride-through performance of the double-fed type wind generating set is greatly improved.

Description

technical field [0001] The invention belongs to the field of wind power generation, in particular to a low-voltage ride-through control method for a doubly-fed wind power generator set based on an electromagnetic transient algorithm. Background technique [0002] Doubling-fed wind turbines are currently the mainstream models of megawatt-level variable-speed constant-frequency wind turbines. With the improvement of wind power grid penetration, the low-voltage ride-through (LVRT) function of wind turbines is a must for current wind turbines. backup function. For example, the grid code for high and extra high voltage issued by the German E.ONNetz power grid company in 2006, and the enterprise standard of the State Grid Corporation of China (Q / GDW392-2009) have all put forward specific requirements for the LVRT function of wind turbines. Due to the special drive topology of the DFIG in the DFIG, it is difficult for the back-to-back drive converter to meet the current capacity r...

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Problems solved by technology

Although this control strategy can make the attenuation speed of the DC flux linkage reach the fastest when the grid voltage fails, it ignores the control of the transient compensation current angle, so it cannot make the rotor end of the double-fed motor The transient voltage is minimized, and the main reason for the loss of control of the doubly-fed wind turbine when the grid voltage drops is that the transient voltage exceeds the voltage controllable range of the rotor-side converter

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