A hybrid control method and system for suppressing current distortion at zero-crossing point of micro-inverter

A micro-inverter and current distortion technology, which is applied to the hybrid control method and system field of micro-inverter zero-crossing current distortion suppression, can solve the problem of complex control algorithm, high current sampling accuracy, unsuitable for micro-inverter, etc. problem, to achieve the effect of achieving power balance, improving zero-crossing distortion, and improving zero-crossing distortion problems

Active Publication Date: 2017-04-05
JIANGSU UNIV
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Problems solved by technology

[0005] Although the above methods all play a certain role in improving the output current distortion, they generally have the disadvantages of high current sampling accuracy and complex control algorithms, and are not suitable for price-sensitive micro-inverters.

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  • A hybrid control method and system for suppressing current distortion at zero-crossing point of micro-inverter
  • A hybrid control method and system for suppressing current distortion at zero-crossing point of micro-inverter
  • A hybrid control method and system for suppressing current distortion at zero-crossing point of micro-inverter

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Embodiment Construction

[0029] The zero-crossing distortion problem to be solved by the present invention and specific solutions will be described in detail below in conjunction with the accompanying drawings and technical solutions.

[0030] figure 1 For the micro-inverter topology studied in this paper. In order to simplify the working process of the system, it is assumed that all the components in the circuit are ideal. When power devices s 1 When turned on, the photovoltaic device gives the excitation inductance L m charging, the current i on its magnetizing inductance Lm Rise linearly and store energy in it. when s 1 When turned off, the inductance L m The operating current reaches a peak value, as shown in formula (1). At the same time, the energy is transferred to the secondary side of the transformer HT.

[0031] I Lm =U PV × d 1 ×T / L m (1)

[0032] where I Lm is the magnetizing inductance L m peak current; U pv is the output voltage of the photovoltaic device; d 1 for the p...

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Abstract

The invention discloses a hybrid control method and system for microinverter zero crossing point current distortion suppression. The method includes the steps that voltage amount and current amount are acquired and calculated, two paths of complementary power frequency switch signals are generated through acquired network voltage effective values Ugrid by a zero crossing comparator circuit, the two paths of complementary power frequency switch signals are sent to a power device s2 and a power device s3, and eventually the secondary side of a transformer HT is controlled to form complete sine waves; detected output current signals io of a microinverter are compared with reference output current signals iref of the microinverter, formed error signals delta io are compared with given Kp, then the work state of the microinverter is judged, when the difference value between zero crossing point grid connection currents and reference grid connection currents is larger than a given value, the power devices are turned off, the zero crossing point distortion problem is effectively solved, and power balance of the system is achieved. According to the method, the reason for zero crossing point distortion is fundamentally analyzed, and provided control policies have the obvious effect on improvement of zero crossing point distortion.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic grid-connected power generation, and in particular relates to a hybrid control method and system for suppressing zero-crossing current distortion of a micro-inverter. Background technique [0002] Photovoltaic power generation is one of the means to solve the world energy crisis. Existing photovoltaic modules are widely used in the form of series, parallel or series-parallel connection, and the power conversion efficiency of photovoltaic modules will be reduced due to the characteristics differences between modules, partial shadows and other issues. Micro-inverter can effectively solve these problems, and it has the advantages of small initial investment, low installation cost, easy maintenance, etc., and has gradually become a hot spot in photovoltaic power generation research. [0003] In order to meet the grid-connected requirements, the total harmonic distortion (THD) of the sinusoidal c...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M7/48H02J3/38H02M1/12
CPCY02E10/56
Inventor 张超韦庭张舒辉
Owner JIANGSU UNIV
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