DFIG (Double-Fed Induction Generator) system control method based on resonance sliding mode

Abstract

The invention discloses a DFIG (Double-Fed Induction Generator) system control method based on a resonance sliding mode. By adopting direct torque / power control, the electromagnetic torque and the reactive power of a motor and the active power and the reactive power output by a grid-side converter can be directly controlled. Moreover, since steps of extracting complex negative sequence and all harmonic components and calculating rotor current reference values are eliminated, decomposition delay is not introduced. Through sliding mode control based on resonance, negative influences introduced by grid voltage harmonic to the electromagnetic torque and the reactive power of the motor and the active power and the reactive power of the grid-side converter can be eliminated, so that the effects of stable output, smaller steady-state errors and better dynamic response characteristics are reached and the expected control effect is reached. The DFIG system control method based on the resonance sliding mode has the advantages that since extraction of the complex negative consequences and all the harmonic components are not required to be conducted and grid voltage phase estimation and complex current reference value calculation are also not required to be conducted, the control delay can be greatly reduced and the rapidness and the stability of the system are enhanced.

Description

technical field [0001] The invention belongs to the technical field of wind power generation control, and in particular relates to a control method for a DFIG system based on a resonant sliding mode. Background technique [0002] As a clean and renewable energy, wind energy has been highly valued by countries all over the world in recent years. The reserves of wind energy are huge. With the development and utilization of wind energy, the global wind power generation has maintained rapid and continuous growth for many years. The doubly-fed asynchronous wind generator (DFIG) system is widely used due to its own constant-speed variable-frequency operation capability, the required converter capacity only accounts for about 30% of the unit capacity, and four-quadrant operation capability. However, the DFIG system operating under harsh grid voltage conditions such as unbalance and harmonic distortion will show some operating performances such as output current distortion and unba...

AI Technical Summary

Problems solved by technology

The complex calculations and multiple uses of the second-order generalized integrator in the process of extracting positive and negative sequences and harmonic components mentioned above will cause a large control delay, which will easily cause unstable operation of the system and reduce the rapidity of system response.

In addition, the calculation process of the rotor current reference value is complicated, and the calculation results need to be rotated to the positive synchronous speed rotating coordinate system, which also adversely affects the rapidity and stability of the system operation

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