Transient energy function method considering vsg inverter current limit

A transient energy function and current limiting technology, which is applied in electrical digital data processing, instruments, calculations, etc., can solve problems such as slow calculation speed, inability to quantitatively analyze stability, and no fundamental guidance for safe and stable operation of the power grid.
CN107330193BActive Publication Date: 2020-10-30NANJING UNIV OF SCI & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
NANJING UNIV OF SCI & TECH
Publication Date
2020-10-30

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Abstract

The invention provides a transient energy function method in consideration of VSG inverter current limitation. The method comprises the steps that a current limitation model of an inverter is built; the power-angle characteristic under inverter current saturation is obtained; a system power-angle model in consideration of inverter saturation under a VSG strategy is built; an improved inverter current saturation element model is built, and a relation of an improved power angle and an unsaturated power angle is obtained; main parameters of electric parts are input; a Runge-Kutta method is used for solving a rotor motion equation to obtain delta(t) and dotted delta(t) of a VSG rotor, so that a fault trajectory is obtained, wherein delta(t) represents a relation of the system power angle and time, and dotted delta(t)=w(t) represents a relation of the system angular velocity and time; transient energy Vcl and critical energy Vcr of the system at the fault clearing time are obtained; the obtained transient energy Vcl and critical energy Vcr of the system at the fault clearing time are compared, if Vcl is smaller than or equal to Vcr, the system is stable, otherwise, the system is not stable; critical fault-clearing time is solved.
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Description

technical field

[0001] The invention relates to a power system transient stability analysis and a nonlinear power electronic device saturation characteristic research technology, in particular to a transient energy function method considering the current limit of a VSG inverter. Background technique

[0002] With the continuous expansion of wind power scale, the number of power electronic converters such as grid-connected inverters connected to the grid has also increased rapidly. Because power electronic devices adopt digital circuit control mode, the transient response time is short, when there is a power disturbance or power imbalance in the grid, it is impossible to use the kinetic energy stored in the rotor to suppress power or frequency like a traditional synchronous generator fluctuations. Based on this, in order to solve the stability problem caused by the inertialess characteristics of the inverter in the wind power system, foreign researchers first proposed the vi...

Claims

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