Photovoltaic grid-connected inverter active support control method based on standard three-order model of synchronous generator

Abstract

The invention discloses a photovoltaic grid-connected inverter active support control method based on a standard three-order model of a synchronous generator. The method comprises the steps of: performing modeling according to a rotor motion equation and a transient voltage equation of a synchronous generator; and simulating an excitation link and a speed regulation link of the synchronous generator to solve the problems of small inertia and small damping of a power system, wherein the control strategy enables the photovoltaic grid-connected inverter to have the external characteristics of a synchronous generator, the control structure gets rid of a PLL phase-locked loop used for photovoltaic grid connection, grid-connected inverter control does not change depending on network frequency changes, and the autonomy and disturbance rejection of inverter control are improved. The Boost converter achieves MPPT control and simultaneously completes unit power factor sine wave voltage stabilitycontrol of the grid-side inverter; the photovoltaic grid-connected inverter plays a role in stabilizing and supporting the frequency, and the exciter gets rid of the effect of a reactive feedback loop arranged according to the reactive-voltage droop characteristic on voltage adjustment, plays a role in stabilizing and supporting the voltage, and improves the photovoltaic grid-connected stability.

Description

technical field [0001] The invention belongs to the technical field of grid-connected new energy sources, and in particular relates to an active support control method for a photovoltaic grid-connected inverter based on a standard third-order model of a synchronous generator. Background technique [0002] As one of the most abundant renewable energy sources in the world, solar energy has the advantages of environmental protection, pollution-free, and abundant reserves. It stands out among many renewable energy sources and has become the most ideal alternative energy recognized internationally. Grid-connected inverter, as the interface device between photovoltaic cells and the power grid, converts the power generated by photovoltaic cells into alternating current and transmits it to the large power grid. It is the core device of the entire system, and the control strategy of photovoltaic grid-connected is the key to distributed power. In general, the maximum power tracking co...

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Problems solved by technology

And when the above control strategy is adopted, the distributed inverter power supply cannot provide a certain support for the power system. On the contrary, in some cases, harmonics will be injected into the grid, and the inverter itself does not have rotational inertia and damping components. , with the massive access of distributed energy, it is bound to bring challenges to the security and stability of the power system

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