System and method for controlling doubly-fed wind power generation grid-side converter

Abstract

The invention discloses a system and a method for controlling a doubly-fed wind power generation grid-side converter. The system comprises a model predictive control module and a space vector modulation module. The model predictive control module controls a voltage transfer function according to dq-axis current and the dq axis of the grid-side converter, acquires a first-order difference equation of a PWM-VSR (pulse width modulation voltage source rectifier) after discretization to serve as a predictive control model and calculates control voltage of the grid-side converter in a real-time online manner by feedback correction and rolling optimization. The space vector modulation module generates a switching signal for operation of the grid-side converter according to the control voltage and controls the grid-side converter in grid-connected operation. By the aid of the system and the method, the influence of lagging of the control voltage caused by sampling delay of voltage and current of the grid-side converter can be eliminated, grid-side dq-axis current is completely decoupled, the negative influence of grid-side inductance parameters on stability and dynamic response of the system can be overcome, three-phase input current effectively tracks input power grid voltage phase, and the grid-side converter is ensured to be operated in a high power factor state.

Description

technical field [0001] The invention belongs to the technical field of wind power converter control, and in particular relates to a discrete optimization control method for unit power factor operation of a grid-side converter. Background technique [0002] In the field of wind power generation, especially for today's medium and high-power wind turbines, doubly-fed wind turbines occupy a dominant position. The system structure of doubly-fed wind turbine is as follows: figure 1 As shown, it is mainly composed of wind turbine, gearbox, doubly-fed generator, converter and main controller. First, the wind turbine absorbs wind energy to generate mechanical torque, and then drives the generator rotor to rotate through gear boxes and other transmission devices, thereby transmitting the mechanical power to the generator; the rotor winding itself is connected to the excitation current to establish a magnetic field. Due to the rotation of the rotor, The electromotive force is induced...

AI Technical Summary

Problems solved by technology

PID control has the advantages of simple structure and easy implementation, but the adjustment time of the control process is too long, and the dynamic adjustment ability of the system is poor; and the system cannot be decoupled, so it is difficult to meet the requirements for the control quality of the grid side system

State feedback control can decouple the control variables to achieve independent control of active power and reactive power. However, any perturbation of the controlled object will lead to decoupling damage, and the control algorithm is more complicated and difficult to implement.

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