Stability determination method for DC distributed system in peer-to-peer control mode

Abstract

The invention relates to the stability analysis technology of the DC distributed system and aims to provide a stability determination method for a DC distributed system in a peer-to-peer control mode.The method comprises steps that Thevenin / Norton equivalent is carried out for a power source or a load through utilizing a unit connection method, an impedance matrix or an admittance matrix is constructed according to impedance or admittance of the power source, the load or a system mode; each matrix is inputted to stability criteria to acquire characteristic values of a system, if the characteristic values of the system are all on a left half plane, the system is stable; if characteristic values of a right half plane are contained in the characteristic values of the system, the system isunstable. The method is advantaged in that the stability criteria has no specific requirements for the system structure, the method is suitable for radiation type systems and annular systems, and theapplication scope is wide; the method can be used for effectively analyzing stability of complex DC distributed systems including multi-sagging control type power sources, current control type power sources, constant current loads, constant power loads and system inter-node impedance, and impedance regulation measures are carried out to guarantee stability of the systems.

Description

technical field [0001] The invention belongs to the stability analysis technology in the DC distributed system technology, and in particular relates to a stability judgment method of the DC distributed system under a peer-to-peer control mode. Background technique [0002] With the massive access of renewable new energy, the DC distributed system is widely used as a highly efficient system. A DC distributed system is generally composed of multiple power supplies, loads and other power modules. Multiple power supplies adopt peer-to-peer control, that is, multiple controllable and adjustable energy storage units adopt droop control for voltage support and current sharing. , the photovoltaic power generation unit with large random fluctuation adopts current control as the current control type power supply. Usually, a single power module can ensure stability when running independently during control design, but it will affect each other when forming a system, reducing system st...

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Problems solved by technology

The document "Reduced-order model and stability analysis of low-voltage DC microgrid" establishes a complete state space model of the ring network DC distributed system, and obtains the characteristic root of the system matrix to analyze the stability of the system, but requires a detailed model of each part of the system. The obtained system matrix is ​​also complex, and the physical meaning corresponding to each matrix element is not clear

The document "Modeling and analysis of harmonic stability in an AC power-electronics-based power system" applies the unit connection method to the master-slave controlled AC microgrid to analyze the system stability, which has a clear physical meaning and can be measured by an impedance analyzer. The impedance and admittance of each power module are modeled, but the admittance matrix of the system node is not separated from the impedance of other parts. It is difficult to intuitively obtain the generalized stability criterion of the system, which is not conducive to expansion

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