Highly-efficient inverter fractional order voltage and frequency control method under microgrid off-grid mode

Abstract

The invention discloses a highly-efficient inverter fractional order voltage and frequency control method under a microgrid off-grid mode. A mechanism modeling method and abc / dq coordinate transformation are employed to establish a state space model of an inverter in dq coordinates under the microgrid off-grid mode. Droop control, fractional order voltage PI control and fractional order current PI control are employed as voltage and frequency control method. The weighted values of two performance indexes including an integral value of the product of a voltage offset absolute value and time and the integral value of the product frequency offset absolute value and time serve as fitness functions. A colony evolution method based on adaptive variation operation is designed to optimize and set parameters of a fractional order controller, and optimized control signals generated after coordinate transformation are transmitted to a space vector pulse width modulation module, thereby realizing optimized operation of an inverter under the microgrid off-grid mode. Optimized voltage and frequency control effects under complex conditions and the microgrid off-grid mode can be realized.

Description

technical field [0001] The invention relates to an intelligent control technology in the field of microgrid power electronics technology, in particular to an efficient control method for fractional-order voltage and frequency of an inverter in a microgrid off-grid mode. Background technique [0002] As an important form of efficient application of new energy distributed power, microgrid can promote the large-scale access of renewable energy, and is expected to realize the highly reliable supply of various energy forms for loads. It is widely regarded as a kind of active distribution network Therefore, microgrids have received extensive attention and research and development in recent years. Among them, how to realize the efficient control and energy optimization management of the inverter in the microgrid’s off-grid mode has become one of the research and development hotspots in the field of microgrid technology, and how to design the inverter voltage and frequency in the of...

AI Technical Summary

Problems solved by technology

[0003] At present, the voltage and frequency control technologies of the inverter in the off-grid mode of the microgrid mainly include: (1) V / f control technology, that is, directly based on the deviation between the reference input signal of the set voltage and frequency and the actual measurement signal, the voltage external The dual closed-loop control mode combining the ring integer-order PI control and the current inner-loop integer-order PI control can realize the control of the inverter output voltage and frequency. The advantage is that the control method is simple, and the disadvantage is that the parameter setting of the double closed-loop PI controller is serious Relying on the engineering experience of the designer, the robust performance is poor, and it is difficult to adapt to the optimal control of variable operating conditions; (2) Direct droop control technology, that is, using a droop characteristic curve similar to the traditional generator set to control the distribution of each distribution in the microgrid The voltage and frequency of the power supply, but this control technology is essentially a differential control, which cannot guarantee the optimal operation under the condition of large load changes, and this technology does not consider the problem of rapid recovery of the voltage and frequency control of the microgrid system. It is difficult to guarantee the voltage and frequency quality of the microgrid system under the action of interference signals

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