Microgrid virtual synchronous generator model prediction control method and system

Abstract

The invention discloses a microgrid virtual synchronous generator model prediction control method and a system. The microgrid virtual synchronous generator model prediction control system comprises a virtual synchronous generator and a frequency modulation unit, wherein the virtual synchronous generator mainly has a main circuit and a control system; the main circuit is grid-connected inverter topology and has a renewable energy generation device, a DC / AC converter, an inverter and a filter circuit; the control system is a core for the virtual synchronous generator and comprises a virtual synchronous generator body model and control algorithm; with simulation of mechanical features and electromagnetic features of the virtual synchronous generator, the inverter can have features similar to the synchronous generator; the frequency modulation device is an energy storing device and can absorb or release energy in real time; the energy storage device is accessed to the virtual synchronous generator; and when required power has to be supplemented upon imbalance of the system power, frequency fluctuation can be weakened and system transient power conservation can be guaranteed. System frequency changes can be confined to a safety range by the system, and economic property of the virtual synchronous generator output can be considered at the same time.

Description

technical field [0001] The invention relates to the technical field of microgrid control, in particular to a model predictive control method and system for a microgrid virtual synchronous generator. Background technique [0002] Energy plays an important role in promoting social development. As a clean and efficient energy form, electricity is related to the national economy and people's livelihood. In response to the energy crisis and environmental pressure, distributed energy such as wind energy and solar energy has received more and more attention. [0003] As an effective form of distributed energy utilization, microgrid technology has attracted widespread attention since it was proposed. The microgrid has two modes of grid-connected operation and island operation. In the isolated grid mode, since there is no support from the large power grid, the microgrid needs to rely on its own units to maintain the system voltage and frequency. Its fluctuations are limited within...

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Problems solved by technology

On the one hand, the output of renewable energy is affected by weather conditions and is random, and output fluctuations cause power supply and demand imbalances; on the other hand, in the island mode, the system capacity is relatively small, and the power imbalance caused by load switching cannot be ignored

[0004] When the internal power supply and demand of the system are unbalanced, the frequency fluctuates. If the fluctuation amplitude exceeds the safety threshold, it may affect the safe operation of the converter or frequency-sensitive loads, and even trigger the action of the frequency protection device, resulting in machine and load shedding, reducing power supply reliability

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