Asymmetry coordination direct power control method of double-fed asynchronous wind power generation system

Abstract

The invention discloses an asymmetry coordination direct power control method of a double-fed asynchronous wind power generation system, which adjusts the stator electromagnetism and the reactive power as well as active power and reactive power of a grid side convertor of a double-fed asynchronous generator through a proportional resonance regulator consisting of a proportional regulator and two resonance regulators so as to effectively control the operation sate of the double-fed asynchronous generator and the grid side convertor under the condition without positive sequence and negative sequence current quantity decomposition. The invention can realize the integral optimized control effect of the double-fed asynchronous wind power generation system under the condition of asynchronous failures of an electric fence, eliminates total active and reactive power, electromagnetic torque, and DC bus voltage fluctuation of the doublefed asynchronous wind power generation system because of asymmetrical voltage of the electric fence, effectively improves the operation control property of the double-fed asynchronous wind power generation system under the condition of the voltage failure of the electric fence, and ensures the electric energy quality of power supply and the operation stability and the operation safety of an electricity system.

Description

technical field [0001] The invention relates to a control method of a wind power generator, in particular to an asymmetric coordination direct power control method of a double-fed asynchronous wind power generation system. Background technique [0002] At present, my country's wind power technology mostly stays in the operation control under ideal grid conditions. Since the actual grid often has various symmetrical and asymmetrical faults, it is necessary to carry out research on operation control under grid faults and propose corresponding control technologies. Modern large-scale wind power generation systems mainly include two types: doubly-fed asynchronous generator (DFIG) and permanent magnet synchronous generator, among which the DFIG system is the current mainstream model. In recent years, international research on DFIG unit control technology has mostly focused on low-voltage ride-through operation control under symmetrical faults in the power grid, but asymmetric fau...

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Problems solved by technology

figure 1 In the traditional control method shown, the separation of positive and negative sequences generally adopts 2ω s Frequency notch filter 16 (or low-pass filter, 1 / 4 grid voltage fundamental wave period delay and other methods), in addition to introducing delay in the separation, the control system bandwidth will be affected, which will cause dynamic tracking error and dynamic control effect not ideal

What's more, the circuit cannot distinguish whether the grid voltage is balanced or asymmetrical. If DFIG 3 operates in a state of strict grid voltage balance, the control system will still use a notch filter to separate the rotor variable, which will bring a negative impact on the normal control of the system. Unnecessary delay is caused, which seriously affects the dynamic control performance of the system

In addition, since the traditional DFIG 3 control method only has four controllable quantities of positive sequence d and q axis components and negative sequence d and q axis components of the rotor current, it can only control the average value of active and reactive power of the stator, and then Selectively eliminate the double-frequency oscillation in the active or reactive power of the stator, but cannot eliminate the double-frequency oscillation in the stator active, reactive power, and electromagnetic torque at the same time, let alone take into account the stator active, reactive power, and electromagnetic torque. Fundamental frequency oscillations in moments

[0010] Documents III and IV propose to use GSC 28 to compensate the double-frequency oscillation component in the active power of DFIG 3 stator, but the control of GSC 28 also needs to use positive and negative sequence separation and dual proportional integral regulator 19, and does not consider the GSC 28 The basic frequency oscillation in the output active and reactive power makes the control system complex in structure, slow in dynamic response, and unable to achieve the expected control effect

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