Island microgrid voltage frequency control method based on model predictive control

Abstract

The invention provides an island microgrid voltage frequency control method based on model predictive control. The microgrid comprises a photovoltaic power generation unit, an energy storage unit, a power converter unit and a load. A control system comprises a model predictive control system, a storage battery power control system, a photovoltaic cell MPPT tracking system and an inverter controller. The model predictive control method comprises three parts of model prediction, rolling optimization and feedback correction, wherein a filter voltage current state equation and load current prediction under a dq0 coordinate are adopted for model prediction; an optimized objective function considers the microgrid frequency and voltage under the island operation mode; the optimal control variablewhich meets the minimum deviation of the voltage frequency of the grid side in the prediction step size is found out through rolling optimization; and the feedback correction is used for correcting the prediction model by sampling the power grid state of the current moment, so as to prevent the control deviation caused by model mismatching and environmental disturbance.

Description

technical field [0001] The invention relates to a control method in the field of power systems, in particular to a method for controlling the voltage and frequency of an island microgrid based on model predictive control. Background technique [0002] A microgrid is a small system that combines distributed power sources, loads, energy storage devices, power converters, and monitoring and control systems. Through the operation control of the microgrid, grid-connected or islanded operation can be realized. At present, under the condition of isolated island operation, due to the strong uncertainty, time-varying and nonlinearity of the microgrid, it is quite difficult to obtain an accurate mathematical model. Although classical control theory and modern control theory have precise theoretical design method and high control accuracy, but both require an accurate model of the control object, so the control effect is not ideal. Therefore, the voltage frequency control of the micr...

AI Technical Summary

Problems solved by technology

At present, under the condition of isolated island operation, due to the strong uncertainty, time-varying and nonlinearity of the microgrid, it is quite difficult to obtain an accurate mathematical model. Although classical control theory and modern control theory have precise theoretical design method and high control accuracy, but both require an accurate model of the control object, so the control effect is not ideal

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