Measurement of VSG inertia and damping coefficient based on nonlinear least square curve fitting

A technique of least squares and measurement method, which is applied in the direction of AC network circuits, electrical components, circuit devices, etc., and can solve problems affecting the external characteristics of distributed power sources, ignoring inverters, and affecting inertial support effects, etc.

Pending Publication Date: 2018-12-18
NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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Problems solved by technology

However, due to the influence of some nonlinear parts in the control algorithm and the PI regulator, the actual output moment of inertia and damping of the inverter may have a certain deviation from the given value, which will affect the actual external characteristics of the distributed power supply. And then affect the effect of inertial support
The current research mainly focuses on the application of VSG technology, while ignoring the current situation of measuring the actual characteristics of the inverter after using VSG technology

Method used

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  • Measurement of VSG inertia and damping coefficient based on nonlinear least square curve fitting
  • Measurement of VSG inertia and damping coefficient based on nonlinear least square curve fitting
  • Measurement of VSG inertia and damping coefficient based on nonlinear least square curve fitting

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Embodiment Construction

[0014] The invention will be described in further detail below in conjunction with the accompanying drawings.

[0015] The rocking equation of the virtual synchronous machine is:

[0016]

[0017] Where J is the inertia; D is the damping parameter; ω is the angular velocity of the rotor; ω g is the grid angular frequency; P m is the mechanical power; P e is the electromagnetic power.

[0018] figure 1 It is the circuit structure diagram of grid-connected inverter controlled by VSG. For the active loop in VSG control, the inner-loop control delay is ignored under grid-connected conditions, and the simplified model structure can be obtained as figure 2 shown

[0019] The simplified synchronous power K in the figure p =EU / Z, the equivalent impedance Z is the sum of VSG virtual impedance, line impedance and stray impedance.

[0020] The nonlinear least squares method is a method to estimate the unknown parameters in the nonlinear function based on the minimum sum of th...

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Abstract

The invention discloses a VSG inertia and damping coefficient measuring method based on nonlinear least square curve fitting, the method analyzes that the system is on the off-line, The time domain unit step response functions of different operating conditions and damping states are analyzed qualitatively. The method of solving inertia and damping coefficients by using dynamic response indexes isqualitatively analyzed. A load rejection test for inertia measurement of synchronous generators is used for reference, and a self-verifiable comprehensive measurement method is obtained by combining power step test. By synthesizing the two experimental methods, the influence of inaccurate synchronous power value on parameter measurement is avoided, which provides a new method for external characteristic measurement of VSG.

Description

technical field [0001] The invention belongs to the technical field of new energy power systems and micro-grids, and in particular relates to a measurement method for VSG inertia and damping coefficient of nonlinear least squares curve fitting. Background technique [0002] Compared with traditional fossil energy sources such as petroleum and coal, new energy sources represented by wind energy and photovoltaics are renewable and clean, and are therefore increasingly recognized and favored. Distributed power generation has become an important development form of new energy development because of its flexible configuration, small investment, and in line with the development concept of renewable energy green and environmental protection. However, a large number of different types of distributed power access systems can easily cause a greater impact on the power grid, and have a great impact on the power flow distribution, power quality and even stable operation of the power gri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/24
CPCH02J3/24H02J3/381H02J2203/20
Inventor 颜湘武王俣珂赵帅帅孙雪薇
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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