Research on Active Power Reserve Grid Support Control Strategy of Single-stage Grid-connected inverter

Abstract:
In recent years, photovoltaic power generation has developed rapidly. But photovoltaic power generation has randomness and volatility, a large number of photovoltaics are integrated into the power grid, which brings challenges to the power balance of the power grid. At the same time, due to the limited absorptive capacity in some areas, photovoltaic power stations have a certain degree of light abandonment. In order to make the photovoltaic system obtain the ability of frequency regulation and voltage regulation, and improve the utilization rate of light energy, this paper proposes an active power reserve (APR) grid support control strategy based on single-stage three-level grid-connected inverter. The control strategy does not require energy storage equipment. The inverter can quickly switch between the traditional MPPT mode and the active power reserve mode. In the active power reserve mode, the system can reduce the photovoltaic output, and has the ability of primary frequency regulation and primary voltage regulation to actively support the grid. In addition, aiming at the problem of inaccurate active power reserve control when the external conditions change suddenly, this paper proposes a constant power voltage monitoring method, which can find the maximum power in time when the environment changes, and ensure the accuracy of reserve power control. In this paper, the operation mode and basic working principle of active power reserve are analyzed, and the parameters are designed. Then the algorithm principle of constant power voltage monitoring method is introduced. Finally, the simulation model and 10kW experimental platform are built to verify the effectiveness and feasibility of the proposed control strategy.