VSG optical electricity-storage energy grid-connected power generation system

Abstract

The invention relates to a VSG optical electricity-storage energy grid-connected power generation system. The system comprises a photovoltaic panel, a first direct current converter, an inverter and a power grid which are connected in sequence; a second direct current converter is connected between connecting lines of the direct current converter and the inverter in a lap joint mode; the second direct current converter is connected with a first energy storage device; and a load is connected between the connecting lines of the inverter and the power grid in a lap joint manner. The system is characterized in that an alternating current inverter is connected between the connecting lines of the inverter and the load in a lap joint manner; and the alternating current inverter is connected with a second energy storage device. Compared with the prior art, a photovoltaic module can always output at the maximum power on the basis of ensuring the output required power, and the working efficiency of the photovoltaic module is improved.

Description

technical field [0001] The invention relates to the field of photovoltaic-storage grid-connected power generation systems, in particular to a VSG light-storage grid-connected power generation system. Background technique [0002] Traditional VSG photovoltaic grid-connected power generation systems equipped with energy storage systems such as figure 1 As shown, it adds an energy storage system on the basis of a two-stage photovoltaic grid-connected power generation system to stabilize the fluctuation of photovoltaic output power. The energy storage system consists of an energy storage device, a DC / DC converter and an energy management system. The voltage control of the DC bus of the power generation unit is realized through the integrated optical-storage system, and the virtual synchronous generator technology enables the inverter not only to realize the power conversion from DC to AC, but also to automatically adjust according to the system frequency and voltage abnormaliti...

AI Technical Summary

Problems solved by technology

[0003] 1. Due to the volatility and randomness of photovoltaic output, it will lead to frequency fluctuations of the power grid system, and the overall output characteristics of solar-storage are regulated and controlled by a unified inverter, which increases the difficulty of control and reduces the stability of the system

[0004] 2. In the traditional photovoltaic-storage grid-connected power generation system, the photovoltaic array needs to adjust its output in time to maintain the stability of the system frequency and voltage in response to changes in the demand of the grid-side load, and it cannot continue to output at maximum power

[0005] 3. Although the traditional VSG light-storage control system can effectively solve the frequency mutation problem caused by small load fluctuations on the grid side, due to the limitation of energy storage, it is unable to deal with the power fluctuations of high-power devices on the grid side. Failure to provide sufficient power supply in a timely and effective manner

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