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Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation

A seamless switching and control method technology, applied in sustainable manufacturing/processing, single-network parallel feeding arrangement, climate sustainability, etc., can solve problems such as shortening switching time, avoid grid-connected overcurrent, and reduce costs , fast and stable seamless switching effect

Active Publication Date: 2016-07-13
SHENYANG INST OF AUTOMATION - CHINESE ACAD OF SCI
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Problems solved by technology

[0004] In order to solve the problem of providing continuous and high power supply to sensitive loads in the system when the grid-connected / islanded conversion occurs during the operation of the micro-grid, the present invention proposes a seamless switching control of the micro-grid inverter from grid-connected based on phase angle estimation method, shorten the switching time, and at the same time avoid the overcurrent phenomenon that occurs when the phase angle of the inverter output is not completely synchronized with the phase angle of the large power grid when the grid is connected

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  • Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation
  • Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation
  • Microgrid inverter grid disconnection/connection seamless switching control method based on phase angle estimation

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Embodiment Construction

[0028] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

[0029] exist figure 1 In , the circuit breaker K1 is installed at the grid-connected point of public coupling (PCC), which is responsible for implementing the grid-connected and off-grid operations of the microgrid. The inverter controller does not need to obtain the state of K1. Install a voltage sensor PT1 and a current sensor CT1 on the PCC grid side to measure the grid voltage and the current value flowing through the PCC point respectively. The key to seamless switching lies in the switching process of the working mode of the energy storage system (main power supply).

[0030] Use the voltage sensor PT1 to measure the line voltage of the three-phase grid voltage, and input it to the PLL phase-locked loop in the controller. The phase-locked loop obtains the grid angular frequency and real-time phase angle value, and stores them in the co...

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Abstract

The invention relates to a microgrid inverter grid disconnection / connection seamless switching control method based on phase angle estimation. An energy storage system serves as a main power supply, and comprises an energy storage battery, a current transformer, and a PCS mode controller. In a grid connection mode, PQ control is employed; in an island mode, V / F control is employed. During the switching from the grid connection mode to the island mode, a voltage amplitude reference value is given by a phase voltage peak value of a power grid before grid disconnection, and is calculated through a mean value of angular frequency of the power grid before grid disconnection and an instant phase angle at the moment of grid disconnection. During the switching from the island mode to a grid connection mode, a phase angle reference value of the inverter in the V / F mode is modified through a phase angle estimation algorithm based on an instant voltage value of the power grid, the phase angle of the power grid is tracked quickly, and a precise voltage phase angle is employed for replacing an estimation value after the stable phase locking of PLL. Through the superposing of frequency interference quantities, the method judges whether the grid connection of a microgrid is completed or not. The method changes the corresponding control modes, and achieves the seamless switching.

Description

technical field [0001] The present invention relates to the technical field of microgrid control, in particular to the microgrid seamless switchover technology of microgrid including distributed power source separation / grid-connection, specifically a seamless switching control of microgrid inverters from grid-connection based on phase angle estimation method. Background technique [0002] With the development of distributed generation and modern power system. Microgrid is proposed as a new type of power distribution solution. It can not only improve the quality and reliability of power supply, but also reduce energy and environmental pressure, so it has won more and more attention. The microgrid system consists of distributed new energy generation, energy storage and local loads. Among them, the combination of energy storage equipment and renewable energy power generation technology can improve power quality, system stability and resource utilization, and stabilize the in...

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Application Information

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IPC IPC(8): H02J3/38
CPCY02P80/14
Inventor 卞晶臧传治曾鹏
Owner SHENYANG INST OF AUTOMATION - CHINESE ACAD OF SCI
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