Novel software phaselock technique applicable to micro-grid master-slave control

A micro-grid and technology technology, applied in the field of new software phase locking, to achieve the effect of simple and reliable judgment logic, easy software implementation, and improved security

Inactive Publication Date: 2012-12-19
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS +1
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Problems solved by technology

[0005] The present invention aims to propose a new type of software phase-locking technology suitable for micro-grid master-slave control to solve the problem of smooth transition when the two operating modes of the micro-grid are switched

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  • Novel software phaselock technique applicable to micro-grid master-slave control
  • Novel software phaselock technique applicable to micro-grid master-slave control
  • Novel software phaselock technique applicable to micro-grid master-slave control

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Embodiment Construction

[0021] Below in conjunction with accompanying drawing, the present invention is described in further detail:

[0022] The overall control structure block diagram of the microgrid main control inverter is as follows: figure 1 As shown, the main symbol name of the main circuit: (1) V in - Input DC voltage. (2)C in ——Input DC side capacitance. (3) L a , L b , L c ——Three-phase filter inductor. (4)C a , C b , C c - Three-phase filter capacitor. The output terminal of the microgrid main control inverter is connected to the microgrid feeder, and the microgrid is connected to the public grid through the point of common connection (PCC). During grid-connected operation, the microgrid main control inverter adopts single current loop control, and the output voltage of the inverter tracks the grid voltage phase; during island operation, the microgrid main control inverter becomes a double-loop control of the voltage outer loop current inner loop Strategy, at this time the mai...

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Abstract

The invention relates to a novel software phaselock technique applicable to micro-grid master-slave control. In a master-slave control structure of a micro-grid, a micro-grid master control inverter tracks the phase of a power grid while in grid-connected operation; and when in isolated island operation, the micro-grid master control inverter needs to maintain the system frequency to be unchanged; to ensure that the phase and the frequency of a voltage do not change suddenly during the micro-grid mode switching process, the invention provides the novel software phaselock technique; when the connected grid is changed to the isolated island mode, the phase of the power grid is locked; and an output phase after the grid is disconnected transits from the power grid phase to the micro-grid phase gradually, and no phase jump happens; when the isolated island mode is changed to the connected grid, a phase difference of the power grid and the micro-grid is firstly calculated, and subsequently the PI modulation is carried out on the phase difference; the output is used as a frequency compensating signal to be overlapped with the frequency under the isolated island mode and to be used as frequency reference of an output voltage of the micro-grid main control inverter; and by changing the frequency, the phase of the micro-grid main control inverter is enabled to approach to the phase of the power grid slowly; and when the phase difference of the micro-grid main control inverter and the power grid is less than a set value (theta0), the grid connection operation is carried out.

Description

technical field [0001] The invention relates to a new type of software phase-locking technology suitable for micro-grid master-slave control, which belongs to the micro-grid inverter control technology in the power conversion technology. Background technique [0002] Microgrid technology provides an effective method for large-scale distributed power applications, and is a combination of new power electronics technology, distributed power generation, renewable energy power generation and energy storage technology. There are two typical operation modes of microgrid: grid-connected mode and island mode. In the master-slave control structure of the microgrid, the master inverter tracks the phase of the public grid and adopts constant power control (PQ control) when it is connected to the grid; Constant frequency control (V / f control) provides voltage amplitude and frequency support for the microgrid system. While the slave inverter adopts PQ control in grid-connected and islan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J9/06H02J3/38
Inventor 姬秋华陈新陈杰王赟程
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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