A comprehensive control method for doubly-fed wind turbines for micro-grid transient steady-state frequency optimization

Abstract

The invention relates to a double-fed fan comprehensive control method for optimizing the transient steady-state frequency of a microgrid. The double-fed fan comprehensive control method comprises thefollowing steps that (1) a microgrid system composed of three power sources of wind power, photovoltaic power and synchronous motor is constructed; (2) virtual inertia control is adopted to reduce the dynamic frequency deviation during the transient frequency supporting phase when a fan participates in frequency modulation; (3) active-power frequency droop control is adopted to improve the steady-state frequency in the steady-state frequency recovery phase when the fan participates in frequency modulation; and (4) the droop control parameters of the fan are taken as control variables, a multi-objective programming model which taking dynamic frequency deviation on a terminal bus, steady-state frequency deviation of a system, fan output power and rotor speed recovery time as evaluation indexes is constructed, and the optimal droop control parameters of the fan are obtained through particle swarm optimization to complete DFIG comprehensive control including the virtual inertia control and the droop control. Compared with the prior art, the double-fed fan comprehensive control method has the advantages of improving rotor kinetic energy, fully participating in frequency modulation andreducing the dynamic frequency deviation and the steady-state frequency deviation.

Description

technical field [0001] The invention relates to the field of doubly-fed wind turbine control, in particular to a doubly-fed wind turbine comprehensive control method for micro-grid transient steady-state frequency optimization. Background technique [0002] Realizing the coordinated frequency modulation control technology of doubly-fed induction generator and synchronous machine is an important part of realizing a grid-friendly wind farm, and it is an important difficulty in improving the capacity of wind power consumption. However, the decoupling control of the rotor side and the grid side of the doubly-fed fan makes the electromagnetic power of the fan unresponsive to the grid frequency, and its high penetration into the grid reduces the inertia of the system, making the system unable to respond to the frequency fluctuation caused by the load mutation in a timely manner, which aggravates the system FM pressure. Therefore, it is an inevitable choice for a high proportion o...

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Problems solved by technology

At present, it has not been explored essentially how the additional virtual inertia of the fan affects the system inertia, and how the inertia slows down the rate of frequency change; most of the current droop control parameters are obtained based on the effect trial and error method, not based on the effect and algorithm optimization, and the existing For the active power reserve required for droop control, a fixed load shedding capacity is reserved, which cannot meet the needs of different load shedding rates

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