Droop control method and system for grid-connected inverter

A control method and inverter technology, applied in the field of distribution network, can solve the problems of low grid frequency and voltage stability, weak robustness of dynamic and steady state process, frequent plugging and unplugging, etc., to maintain safe and stable operation, The effect of improving survivability and reducing the number of times of plugging and unplugging

Inactive Publication Date: 2019-12-24
CHINA ELECTRIC POWER RES INST +1
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

Due to the small inertia, fast, high-frequency power electronic system connected to the large inertia, low speed, and industrial frequency power system, it does not participate in grid regulation, does not support grid fault recovery, difficult management and control, frequent plugging and unplugging, and the robustness of the dynamic steady state process is not good. Many adaptability problems, such as strong and strong, make the grid-connected inverter unable to make corresponding responses in the case of abnormal grid voltage and frequency, and the grid frequency and voltage stability is low

Method used

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  • Droop control method and system for grid-connected inverter
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  • Droop control method and system for grid-connected inverter

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Embodiment 1

[0058] In order to improve the survivability of new energy sources, ensure the stability of the power grid, and demonstrate the economic and social benefits of new technologies, this invention provides two droop control methods that enable grid-connected inverters to have damping and inertia, respectively for power droop control and current droop control To improve, the damping and inertia of the virtual synchronous generator are applied to it, and the grid-connected inverter adopting power droop control and current droop control has damping and inertia characteristics, which improves the stability of grid voltage and frequency, and then maintains Safe and stable operation of the grid system.

[0059] like figure 1 The specific implementation steps shown are as follows:

[0060] Step 1: Obtain grid voltage, current, frequency information, voltage amplitude and angular frequency of the inverter;

[0061] Step 2: Bring the grid voltage, current, frequency information and angul...

Embodiment 2

[0113] Based on the same concept and invention, the present invention also provides a droop control system with damping and inertia for grid-connected inverters, the system includes:

[0114] A droop control system for a grid-connected inverter, the system comprising:

[0115] Obtaining module: used to obtain grid voltage, current, frequency information, voltage amplitude and angular frequency of the inverter;

[0116] The model module is used to bring the grid voltage, current, frequency information and angular frequency into the pre-built virtual synchronous generator rotation model to obtain the phase angle value;

[0117] Synthesis module: used to bring the phase angle value and voltage amplitude into the three-phase voltage synthesis model to obtain a three-phase voltage reference value;

[0118] Control module: for generating PWM waves based on the three-phase voltage reference value and the PWM generator, and controlling the inverter based on the PWM waves

[0119] Th...

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Abstract

The invention provides a droop control method and system for a grid-connected inverter. The method comprises the steps that the acquired power grid voltage, current, frequency information and angularfrequency of the inverter are brought into a pre-built virtual synchronous generator rotation model to acquire a phase angle value; the phase angle value and the acquired voltage amplitude are broughtinto a three-phase voltage synthesis model to acquire a three-phase voltage reference value; a PWM wave is generated based on the three-phase voltage reference value and a PWM generator; and based onthe PWM wave, the inverter is controlled. Due to the damping and inertia characteristics of the grid-connected inverter under power droop control and current droop control, the stability of the voltage and frequency of a power grid are improved. The safe and stable operation of the power grid system is maintained. The viability of new energy is enhanced. Economic and social benefits of the new technology are demonstrated.

Description

Technical field: [0001] The invention relates to the field of distribution networks, in particular to a droop control method and system for grid-connected inverters. Background technique: [0002] Vigorously developing clean energy is one of the effective ways to alleviate the world's energy crisis and environmental degradation. With the rapid development of distributed power generation units with clean energy as the main form in the power system, the penetration rate of clean energy in the grid system is also increasing rapidly. When the power grid system is subjected to large-scale disturbances at the load end, it is easy to cause instability of the power grid system due to the lack of sufficient energy to balance the disturbance in a short period of time. At the same time, distributed energy technology is an important development direction of the world's energy technology in the future. It has the characteristics of high energy utilization efficiency, small negative impa...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02M7/48
CPCH02M7/48
Inventor 吕志鹏孙丽敬吴鸣宋振浩赵婷刘国宇郑楠
Owner CHINA ELECTRIC POWER RES INST
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