A virtual synchronous machine control device and method with dual energy storage

Abstract

The invention discloses a dual-energy-storage adding virtual synchronous machine control device and a method. The device comprises a photovoltaic panel, a direct current side storage battery, an alternating current side storage battery and a load. The photovoltaic panel passes through a direct current converter and then is connected to a direct current bus. The direct current side storage batterypasses through a bidirectional direct current converter, then is connected in parallel with the photovoltaic panel and then is connected to the direct current bus. The alternating current side storagebattery passes through a bidirectional alternating current and direct current inverter and is connected to an alternating current bus. The direct current bus and the alternating current bus are connected through an inverter. The alternating current bus is finally connected to a power grid and the load is directly connected to the alternating current bus. Under control of a virtual synchronous machine, a dual-energy-storage device can stabilize a power grid frequency and a voltage by absorbing or releasing stored electric energy when a photovoltaic power station outputs and the power grid frequency fluctuates. The addition of the dual-energy-storage device is of great significance in eliminating an impact on the power grid generated during a large-capacity photovoltaic grid-connected powergeneration process.

Description

technical field [0001] The invention belongs to the technical field of electrical engineering, and in particular relates to a dual energy storage virtual synchronous machine device and method suitable for megawatt-level photovoltaic power generation. Background technique [0002] At present, the photovoltaic power generation control system using virtual synchronous generator technology usually configures battery energy storage on the photovoltaic DC side, and regards photovoltaic and storage as a whole, and uses VSG control technology for grid-connected inverters to realize photovoltaic power generation. However, for large-capacity, especially megawatt-level photovoltaic power stations, output fluctuations will exceed the control range of traditional virtual synchronous machines. If sufficient energy buffer cannot be provided for virtual synchronous machine frequency and power adjustments, Seriously affect the stability of the virtual sync machine. Before the present invent...

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Problems solved by technology

[0002] At present, the photovoltaic power generation control system using virtual synchronous generator technology usually configures battery energy storage on the photovoltaic DC side, and regards photovoltaic and storage as a whole, and uses VSG control technology for grid-connected inverters to realize photovoltaic power generation. However, for large-capacity, especially megawatt-level photovoltaic power stations, output fluctuations will exceed the control range of traditional virtual synchronous machines. If sufficient energy buffer cannot be provided for virtual synchronous machine frequency and power adjustments, Seriously affect the stability of the virtual sync machine

Before the present invention, Chinese patent applications with application numbers 2015101534250 and 2016109814536 both proposed improvement methods for related problems, but the former control method is not suitable for large-capacity photovoltaic grid-connected power generation process, and the latter only studies the characteristics of energy storage batteries , without considering the external circuit characteristics

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