Direct-current microgrid system and energy management method thereof

Abstract

The invention provides a direct-current (DC) microgrid system and an energy management method thereof. A power generation unit comprises a large user-side power grid and a grid-connected alternating current / direct current converter (AC / DC) thereof, a lithium iron phosphate energy storage system (EMS) and an energy storage direct current / direct current converter (DC / DC), and a photovoltaic power generation system and a photovoltaic DC / DC thereof. The DC microgrid system is provided with EMS and a wireless sensor network thereof, wherein the wireless sensor network is communicated with the grid-connected, energy storage and photovoltaic DC / DC; the EMS is used for executing different control strategies and optimizing the operation of a DC microgrid; the voltage of a DC busbar is stabilized by controlling a DC busbar voltage outer loop and an output inductive current inner loop through the grid-connected AC / DC when a grid-connected operation is switched to an islanding operation; and the islanding operation is switched to an operation using the energy storage DC / DC as a voltage source, i.e. the voltage stability of the DC busbar is maintained by controlling the DC busbar voltage outer loop and the inductive current inner loop on the energy storage side of a battery within the time of at most 20ms. Therefore, a seamless switching requirement is met, uninterrupted power supply (UPS) of loads in a telecom data center is realized, and configuration of reactive-load compensation equipment is avoided.

Description

technical field [0001] The invention relates to a microgrid system, in particular to a DC microgrid system and an energy management method thereof. Background technique [0002] Microgrid is an organizational form of distributed generation (abbreviated as DG), which consists of distributed power, energy storage devices, energy conversion devices, related loads and monitoring systems, and protection devices. The system can realize self-control, protection and management, and can operate in parallel with the external power grid or in isolation. The existing DC micro-grid system is still in the stage of modeling and simulation and the implementation of low-power experimental systems. When switching between island operation and grid-connected operation, there are mostly gap switching, which cannot meet the reliable power requirements of key loads including telecom data centers. If seamless switching is to be realized, the cost is high and the control is difficult. Contents of...

AI Technical Summary

Problems solved by technology

The existing DC micro-grid system is still in the stage of modeling and simulation and the implementation of low-power experimental systems. When switching between island operation and grid-connected operation, there are mostly gap switching, which cannot meet the reliable power requirements of key loads including telecom data centers. If you want to achieve seamless switching, the cost is high and the control is difficult

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