Active damping scheme for multiple LCL inverter resonant coupling

A resonant coupling, inverter technology, applied in harmonic reduction devices, output power conversion devices, and AC networks to reduce harmonics/ripples, etc., to reduce single unit, reduce harmonic distortion rate, and improve reliability. Effect

Inactive Publication Date: 2015-08-05
STATE GRID CORP OF CHINA +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The technical problem to be solved by the present invention is that in order to solve the problem of three kinds of resonance couplings in parallel operation of multiple LCL type inverters in photovoltaic distributed grid-connected power generation technology: self-resonance, parallel resonance and series resonance to the inverter output current quality; at the same time, to improve the reliability of energy metering of traditional full-wave energy metering equipment, an active damping scheme for resonant coupling of multi-LCL inverters is proposed

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  • Active damping scheme for multiple LCL inverter resonant coupling
  • Active damping scheme for multiple LCL inverter resonant coupling
  • Active damping scheme for multiple LCL inverter resonant coupling

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Embodiment Construction

[0044] The specific implementation manners of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0045] like figure 1 as shown, figure 1 It is a schematic diagram of the operation of a parallel grid-connected LCL inverter according to an embodiment of the present invention, including an island micro-grid system composed of several inverters connected in parallel. The inverter mainly includes a DC stabilized voltage source, an inverter circuit, a filter circuit, and a signal conditioning circuits, A / D converters, DSP controllers, drive protection circuits, etc. u dc is the DC bus voltage obtained by rectification of the distributed power supply; u inv is the inverter output voltage; R 1 , R 2 are the parasitic resistances of inverter side and grid side inductance respectively; C f is the filter capacitor; L 1 is the inverter side filter inductance, L 2 is the grid-side filter inductance; i 1 is the inverter side ind...

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Abstract

The invention provides an active damping scheme for multiple LCL inverter resonant coupling. The active damping scheme comprises a distributed grid-connected power generation system formed by the series connection of a plurality of photovoltaic LCL inverters and a full wave energy metering device. The control structure of the current and active damping control link of each of the LCL inverters comprises an inverter reference output current calculation link, a photovoltaic power front feed reference current compensation link, an inverter output current deadbeat control link and an active damping compensation link. According to the control method of the invention, the harmonic distortion rate of grid-connected total current can be reduced, the metering data reliability of the full wave energy metering device is effectively improved, the specific harmonic amplification interference of inverter output current by the self resonant point of a single inverter filtering link is effectively reduced, the parallel connection resonant coupling among multiple inverter filtering links is effectively reduced, the independence of each inverter output current is ensured, and the interference of the inverter output current by power grid harmonic voltage is effectively reduced. According to the active damping scheme, the safe and stable operation of an inverter parallel system can be ensured.

Description

technical field [0001] The invention relates to an active damping scheme for resonance coupling of multi-LCL inverters adapted to grid-connected metering of distributed power sources, and belongs to the technical field of micro-grid distributed photovoltaic power generation. Background technique [0002] The island microgrid with multiple distributed power sources can use droop control to realize parallel operation of inverters without interconnection wires. When the microgrid is connected to the large grid, the grid-connected aggregated bus voltage of the distributed power generation is supported by the large grid voltage. Each grid-connected inverter system adopts a current control scheme to realize the maximum power tracking control of wind power or photovoltaic. [0003] Deadbeat current control is a control scheme based on the mathematical model of the inverter filter circuit. This scheme only needs to obtain the actual electrical parameters of the inverter system, an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M1/12H02J3/38H02J3/01
CPCY02E40/40
Inventor 张春强罗安陈智勇李鸣慎龙际根
Owner STATE GRID CORP OF CHINA
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