Passive quasi-PR control method for photovoltaic grid-connected inverter under weak power grid

A control method and inverter technology, applied in the direction of single network parallel feed arrangement, AC network to reduce harmonic/ripple, harmonic reduction device, etc., can solve problems such as unsatisfactory power quality, and achieve controller performance And grid-connected current quality improvement, good dynamic performance, strong robustness effect

Inactive Publication Date: 2020-06-30
HARBIN INST OF TECH
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Problems solved by technology

[0004] In order to solve the problem of unsatisfactory grid-connected power quality of photovoltaic grid-connected inverters based on traditional passive control under weak grids, the present invention proposes a passive quasi-PR control method for photovoltaic grid-connected inverters under weak grids. The technical scheme is as follows:

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  • Passive quasi-PR control method for photovoltaic grid-connected inverter under weak power grid
  • Passive quasi-PR control method for photovoltaic grid-connected inverter under weak power grid
  • Passive quasi-PR control method for photovoltaic grid-connected inverter under weak power grid

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Embodiment 1

[0052] A passive quasi-PR control method for a photovoltaic grid-connected inverter under a weak grid, the control method is suitable for a weak grid environment with large grid impedance and unstable grid voltage, and the control method includes the following steps:

[0053] Step 1, such as figure 1 As shown, according to the equivalent topology diagram of the single-phase full-bridge inverter under the weak grid, combined with Kirchhoff's law, the state average model for the single-phase grid-connected inverter is constructed for the weak grid grid-connected working environment, and then according to the The above state average model is used to derive the Euler-Lagrange (Euler-Lagrange, EL) mathematical model for single-phase grid-connected inverters in weak grid-connected operating environments;

[0054] Step 2, establishing an energy function of the inverter system and analyzing the energy relationship existing in the inverter system, and then analyzing the passivity of th...

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Abstract

The invention provides a passive quasi-PR control method for a photovoltaic grid-connected inverter under a weak power grid, and belongs to the technical field of photovoltaic grid-connected invertercontrol. The method comprises the following steps: constructing a state average model according to a weak power grid single-phase full-bridge inverter equivalent topological graph in combination withthe Kirchhoff law, and then deriving an Euler-Lagrange mathematical model of a single-phase grid-connected inverter; establishing an energy function of the inverter system, analyzing an energy relationship existing in the inverter system, and then performing passivity analysis on the system to prove passivity of the inverter system; establishing an error energy storage function of the inverter system, and determining the change rate of an error energy storage equation of the inverter system by analyzing the change rate of the error energy storage equation of the inverter system; effectively changing the change rate of the error energy storage equation of the inverter system by adding a damping strategy, and shortening the time for reducing to zero; and firsty sending the error variable inthe error energy storage function to the quasi-PR controller to be processed and then sending the processed error variable to the traditional passive controller to obtain a passive quasi-PR control strategy.

Description

technical field [0001] The invention relates to a passive quasi-PR control method for a photovoltaic grid-connected inverter under a weak power grid, and belongs to the technical field of photovoltaic grid-connected inverter control. Background technique [0002] Photovoltaic grid-connected inverters carry the task of converting the direct current generated by photovoltaic cells into alternating current and sending them into the grid. At the same time, they also need to realize maximum power tracking control according to the operating status of photovoltaic cells. Conventionally designed photovoltaic inverters can achieve relatively good operation control for power grids with strong anti-interference capabilities; however, for weak power grids with large grid impedance, low short-circuit capacity, and easy fluctuations in grid voltage, large-scale photovoltaic inverters The connection of the weak grid is not conducive to the stable operation of the weak grid. At the same tim...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/01
CPCH02J3/01Y02E40/40
Inventor 刘桂花王卫王文秀荆弈翔诸嘉宁崔云鹏
Owner HARBIN INST OF TECH
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