Photovoltaic micro-grid inverter output voltage control method

An output voltage control, micro-grid technology, applied in photovoltaic power generation, irreversible DC power input conversion to AC power output, output power conversion devices, etc., can solve the problem of high harmonic content, inconvenient use, poor stability, etc. problems, to achieve the effect of overcoming high harmonic content, good stability and good sine

CN104333206AActive Publication Date: 2015-02-04XINJIANG HOPE ELECTRONICS
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2015-02-04

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Abstract

The invention discloses a photovoltaic micro-grid inverter output voltage control method which mainly comprises that a-phase voltage is acquired in real time in operation of a photovoltaic micro-grid inverter, fast fourier FFT analysis is performed, total voltage harmonic content THD is calculated, and current factors of three phases of a, b and c are adjusted simultaneously according to the size of total voltage harmonic content THD; and filtering inductance current of all phases of a, b and c is multiplied by the current factors, filtering capacitance current is multiplied by the result of one minus the current factors, and the sum of the two mixed current acts as feedback current of each phase so that output voltage harmonic wave of the photovoltaic micro-grid inverter is enabled to gradually decrease to a preset threshold value. According to the photovoltaic micro-grid inverter output voltage control method, defects of high harmonic content, poor stability and inconvenient use in the prior art can be overcome so that advantages of low harmonic content, great stability and convenient use can be realized.
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Description

technical field

[0001] The present invention relates to the application field of photovoltaic microgrid systems, in particular to a method for controlling the output voltage of a photovoltaic microgrid inverter. Background technique

[0002] The solar photovoltaic power generation industry has been paid more and more attention by people, which has led to rapid development of photovoltaic power generation systems in both grid-connected and off-grid fields, driving the rapid advancement of photovoltaic micro-grid systems. Photovoltaic microgrid systems require photovoltaic inverters to work in both grid-connected and off-grid modes. In the grid-connected mode, the large power grid provides voltage support, and the photovoltaic inverter generally adopts the PQ power control method to realize the grid-connected current control; in the off-grid mode, the photovoltaic inverter itself provides voltage for the local load.

[0003] In the process of realizing the present invention, ...

Examples

Embodiment Construction

[0026] 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.

[0027] The local load is divided into a linear load composed of a resistor R, an inductor L, and a capacitor C, and a nonlinear load composed of a rectifier diode. Photovoltaic inverters under micro-grid conditions mostly use LC filters for output filtering. In the off-grid mode, the outer loop of the controller adopts the output voltage feedback loop, and the inner loop of the controller can adopt two kinds of current feedback control according to the difference of the feedback current: the current of the filter inductor L is collected in real time as the object of the inner loop of the system control, this current Feedback control has a good effect on the voltage ...