Frequency coupling modeling method for single-phase LCL-type grid-connected inverter considering phase-locked loop

A modeling method and inverter technology, applied in the direction of single-network parallel feeding arrangement, AC network circuit, circuit device, etc., can solve the problems of inability to construct input signal, input signal asymmetry, etc. Application, high model accuracy, clear physical meaning effect

Active Publication Date: 2018-11-30
HUNAN UNIV
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Problems solved by technology

In fact, it is impossible to construct a set of input signals that are strictly orthogonal u

Method used

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  • Frequency coupling modeling method for single-phase LCL-type grid-connected inverter considering phase-locked loop
  • Frequency coupling modeling method for single-phase LCL-type grid-connected inverter considering phase-locked loop
  • Frequency coupling modeling method for single-phase LCL-type grid-connected inverter considering phase-locked loop

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Embodiment Construction

[0027] figure 1 It is the circuit topology diagram of single-phase photovoltaic grid-connected system. Among them: the main circuit is composed of a boost circuit, a single-phase full-bridge inverter and an LCL filter; the single-phase full-bridge inverter uses the synchronous reference system theory to control the active and reactive power of the system through the PI controller in the dq coordinate system. power current, the transfer function of the controller is

[0028]

[0029] where k p is the proportional coefficient, k i is the integral coefficient.

[0030] figure 1 Medium, L g is the grid side inductance; L 1 and L 2 are the LCL filter inductors on the inverter side and grid side respectively; R 1 and R 2 L respectively 1 and L 2 The parasitic parameters; C is the LCL filter capacitor; R d is the damping resistance; L g is the grid inductance; u inv is the midpoint voltage of the inverter bridge arm; u s is the inverter output voltage; i s is the i...

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Abstract

The invention discloses a frequency coupling modeling method for a single-phase LCL-type grid-connected inverter considering a phase-locked loop. A frequency domain expression of an inverter modulation signal considering the output phase angle deviation of the phase-locked loop is obtained through a harmonic linearization method; and then a frequency coupling impedance model of the single-phase grid-connected inverter is established according to a main circuit topology and the modulation signal frequency domain expression, and the problem of accurate modeling of the impedance of the single-phase grid-connected inverter is solved; based on the model, system stability and the influence of all system parameters on the frequency coupling degree can be analyzed; and from the established model,it can be seen that the frequency coupling phenomenon mainly occurs at the low frequency, and the coupling current component generated at the high frequency can be almost negligible. According to thefrequency coupling modeling method, the theoretical basis is provided for stability analysis of a new energy grid-connected system.

Description

technical field [0001] The invention relates to the field of renewable energy power generation systems, in particular to a frequency coupling modeling method of a single-phase LCL grid-connected inverter considering a phase-locked loop. Background technique [0002] New energy power generation devices such as wind energy and solar energy need to be connected to the grid through power electronic converters, that is, grid-connected inverters. However, the connection of power electronic inverter devices with high penetration rate to the grid will have an impact on the stability of the system. The premise of stability analysis is to establish an accurate system model. [0003] Scholar Sun Jian proposed to use the method of harmonic linearization to establish the impedance model of a single three-phase LC type grid-connected inverter. This method not only takes into account the inverter parameters and control strategy, but also takes into account the frequency domain The impact ...

Claims

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Application Information

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IPC IPC(8): H02J3/38
CPCH02J3/38H02J2203/20
Inventor 陈燕东王伊伍文华周乐明杨苓谢志为谭文娟谢璐
Owner HUNAN UNIV
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