Fuzzy-control-based virtual synchronous motor's virtual inertia adaptive regulation method and frequency control method

Abstract

The invention discloses a fuzzy-control-based virtual synchronous motor's virtual inertia adaptive regulation method and a frequency control method. The method comprises the following steps: targeted to the micro source of a currently available micro power grid utilizing the virtual synchronous motor control technology for inversion output, using the output frequency error and the error variation rate of the micro source as the fuzzy output; and based on a two-dimensional fuzzy principle, dynamically adjusting the virtual inertia time constant. The invention further provides a frequency control method, comprising: in combination of the mechanical equation of a virtual synchronous motor, adjusting the output frequency of the virtual synchronous motor to strike a balance between the frequency support and dynamic response in its involvement in the concrete frequency adjusting process, to reduce load switching and the frequency fluctuation rising from micro source grid connecting and to ensure the stable frequency and rapid response of the micro power grid under the islanding state.

Description

technical field [0001] The invention relates to the field of inverter control of distributed power sources based on virtual synchronous machine technology, in particular to a virtual inertia adaptive adjustment method and frequency control method of virtual synchronous machines based on fuzzy control. Background technique [0002] In recent years, in order to solve the increasingly prominent energy and environmental problems, the development and utilization of new energy represented by renewable energy such as solar energy and wind energy has received great attention. Distributed power sources including various energy forms have penetrated into microgrids. The frequency of the microgrid is also continuously increasing, which poses a great challenge to the stability of the microgrid. Especially in the case of island operation, the frequency support of the large power grid is lacking, and the common multi-inverter environment makes the frequency of the microgrid affected. The ...

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Problems solved by technology

[0002] In recent years, in order to solve the increasingly prominent energy and environmental problems, the development and utilization of new energy represented by renewable energy such as solar energy and wind energy has received great attention. Distributed power sources including various energy forms have penetrated into microgrids. The frequency of the microgrid is also continuously increasing, which poses a great challenge to the stability of the microgrid. Especially in the case of island operation, the frequency support of the large power grid is lacking, and the common multi-inverter environment makes the frequency of the microgrid affected. The impact of load changes and distributed power switching is obvious, and the transient process of multi-inverter parallel coordination is long, which not only reduces the power quality of the microgrid, but also threatens the safe and stable operation of the microgrid, and reduces the safety of power consumption.

[0003] In order to solve the problems that the response speed of the micro-grid power becomes faster after the electronization of the micro-grid, and the traditional inverter lacks the moment of inertia brought by the synchronous motor, it is difficult to participate in the frequency regulation of the power grid, etc., drawing on the operation experience of the traditional power system, the virtual synchronous machine control technology has been obtained. The purpose of rapid development is to make traditional inverters exhibit similar external characteristics to synchronous motors in the transient process, bring important inertia and damping characteristics in the frequency adjustment process, and provide the necessary voltage and frequency support for the microgrid , to ensure the frequency stability of the microgrid

However, the existing virtual synchronous machine technology is more inclined to design constant control parameters according to the actual situation of the micro-grid. On the one hand, it is not conducive to the distributed power supply to adapt to the structural changes of the micro-grid. Advantages. Conservatively introducing large inertia can bring obvious voltage support to the microgrid and resist load changes, but it will inevitably slow down the dynamic response of the system and lengthen the adjustment time, making the frequency of the microgrid always in an unstable state. Bringing hidden dangers to load safety

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