Method and system for suppressing transformer excitation current instantaneously when inverter is connected to power grid
A technology for grid connection and excitation current, applied in the field of solar photovoltaic power generation, can solve the problems of large energy consumption, increased hardware cost, and high hardware cost
Active Publication Date: 2017-02-15
XINJIANG HOPE ELECTRONICS
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But this kind of circuit will increase the cost of hardware, and there will be energy consumption on the resistor, which will affect the efficiency of the system
[0005] In the process of realizing the present invention, the inventor found that there are at least defects such as high hardware cost, large energy consumption and low energy conversion efficiency in the prior art
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[0074] The preferred embodiments of the present invention will be described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.
[0075] In view of the defects in the prior art, according to the embodiment of the present invention, such as figure 2 As shown, the method and system for suppressing the excitation current of the transformer at the moment when the inverter is connected to the grid are provided, that is, the method for suppressing the excitation current of the transformer at the moment when the power frequency isolated photovoltaic grid-connected inverter is connected to the grid. The method and system for suppressing the excitation current of a transformer at the moment when the inverter is connected to the grid can use software judgment instead of a hardware soft start circuit to ...
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The invention discloses a suppression method and system for the exciting current of an inverter and power grid connection momentary transformer. The method mainly comprises the following steps: starting an inverter and setting the output reference value of the inverter in a synchronous rotating coordinate system as zero; detecting inverter output voltage and power grid voltage converted onto the secondary side of a delta / gamma transformer; converting the detected inverter output voltage converted onto the secondary side of the delta / gamma transformer from a three-phase static coordinate system to a two-phase synchronous rotating coordinate system to obtain ud and uq; converting the detected power grid voltage from a three-phase static coordinate system to a two-phase synchronous rotating coordinate system to obtain vd and vq, wherein when the inverter works till ud is equal to vd and uq is equal to vq, alternating-current voltages at the two ends of a grid-connected switch are synchronous before actuation of the grid-connected switch. By adopting the suppression method and the system for the exciting current of the inverter and power grid connection momentary transformer, the advantages of low hardware cost, low energy consumption and high energy conversion efficiency can be realized.
Description
technical field [0001] The invention relates to the technical field of solar photovoltaic power generation, in particular to a method and a system for suppressing excitation current of a transformer at the instant when an inverter is connected to a power grid. Background technique [0002] At present, with the increasing consumption of fossil energy such as oil, coal, and natural gas and the deteriorating ecological environment of the earth, countries all over the world are actively looking for a new energy source that is sustainable and non-polluting to the ecological environment. As an efficient and pollution-free new energy source, solar energy has become an important part of today's energy structure. Due to the extremely rich reserves of solar energy and the ever-changing power generation technology using solar energy, solar power generation has been widely recognized at home and abroad. Solar grid-connected power generation is an effective way to utilize solar energy, ...
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IPC IPC(8): H02J3/38H02M1/12
CPCY02E10/56
Inventor 戴伟孙向东陈芳王建渊张琦刘越
Owner XINJIANG HOPE ELECTRONICS