A VSC multi-objective optimization direct power control method based on particle swarm optimization in harmonic power grid

Abstract

The invention discloses a multi-objective optimization direct power control method for VSC under a resonance power grid based on particle swarm optimization. Consideration is given to output three-phase stator currents, output active power and output reactive power of the VSC, so that multi-objective optimization control over control performance of the output three-phase stator currents, the output active power and the output reactive power is achieved at the same time, according to the adopted particle swarm optimization, codes are simplified, calculation time is short, which helps real-time calculation to be achieved, operation control performance of the VSC can be effectively improved under resonance power grid voltage conditions, and electric energy quality and stability and safety of a power system are ensured. Meanwhile, a vector proportional integral adjustment or proportional integral resonance adjustment technology is adopted, and angular frequency can restrain adverse effects caused by five or seven harmonic components in power grid voltage for vector proportional integral adjustment or resonance adjustment of six-fold fundamental frequency.

Description

technical field [0001] The invention belongs to the technical field of power equipment control, and in particular relates to a VSC multi-objective optimization direct power control method in a harmonic power grid based on a particle swarm algorithm. Background technique [0002] Nowadays, as a simple and reliable power electronic device, VSC (Voltage Source Converter) is widely used in actual power grids. The most common devices are grid-side converters used in wind power generation systems, and Grid-side converters, active power filters and power factor correction devices to ensure safe and reliable operation of the grid, etc. However, the VSC operating under the condition of harmonic grid voltage will show harmonic distortion of three-phase output current, output active power, reactive power oscillation and other operational performance deterioration. The deterioration of the above performance indicators will cause adverse effects such as grid current harmonic injection a...

AI Technical Summary

Problems solved by technology

However, according to the mathematical model of VSC, the two control objectives in the traditional control strategy are in conflict with each other, and it is impossible to improve the three-phase grid current, output active power and reactive power of VSC at the same time.

That is to say, while achieving a certain control target, it will lead to the deterioration of the performance of another control target. For example, when the three-phase grid current remains sinusoidal, the output active power and reactive power will fluctuate violently at 300 Hz, which is not conducive to the power grid. Reliable and stable operation; similarly, when the 300Hz fluctuation of the output active power and reactive power is eliminated, it will cause the current injected into the grid to be distorted, which is also not conducive to the reliable and stable operation of the grid

Therefore, the traditional control strategy of VSC under the harmonic grid can only focus on one of the two control objectives, but cannot take into account both, so that the performance of the other objective will be greatly deteriorated while achieving one control objective, which is ultimately not conducive to the stability of the power grid. reliable operation

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