Multi-transformer push-pull type photovoltaic inverter

Abstract

A multi-transformer push-pull type photovoltaic inverter comprises a DSP, a DC / DC convertor, a DC / AC convertor and a filter, wherein the DC / DC convertor, the DC / AC convertor and the filter are sequentially connected, and a composite controller which is composed of a PI controller of the DC / AC convertor, an artificial neural network model and a feed-forward arithmetic unit is arranged in the DSP. The input end of the artificial neural network model is connected with the state variable of the DC / AC convertor in the kappath sampling period, a predicted value of the output voltage which is outputted by the artificial neural network model in the (kappa+1)th sampling period is connected with the negative input end of the feed-forward arithmetic unit, the positive input end of the feed-forward arithmetic unit is connected with a set value of voltage at the kappa moment, and an output signal of the feed-forward arithmetic unit is connected with an output signal of he PI controller and then controls the duty ratio of the DC / AC convertor. According to the multi-transformer push-pull type photovoltaic inverter, the output voltage of the inverter at the next moment is predicted through the neural network model, compensation for the duty ratio at the present moment is timely conducted through the feed-forward arithmetic unit, and therefore the hysteresis quality of the PI controller is overcome, and the robustness of the inverter system is improved.

Description

technical field [0001] The invention relates to a multi-transformer push-pull two-stage inverter device suitable for an independent photovoltaic power generation system, which belongs to the technical field of photovoltaic power generation. Background technique [0002] With the increasingly serious energy crisis and environmental pollution, solar photovoltaic power generation, as a clean and green energy, has become a focus of attention and research around the world. [0003] The inverter is a power electronic device that converts DC power into AC power, and is an important part of realizing independent photovoltaic power generation applications. Since the DC voltage output by a single photovoltaic cell module is low, it is necessary to boost the low DC voltage through a DC / DC converter first, and then output a standard AC voltage through a DC / AC conversion circuit. [0004] Most of the existing photovoltaic inverters are controlled by simple PID controllers, which have th...

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Problems solved by technology

[0005] In addition, common step-up DC / DC converters can be divided into BOOST, CUK, push-pull, flyback and other types. These DC / DC converters generally have high voltage and current stress, poor isolation characteristics, limited load capacity, and output voltage Shortcomings such as poor transient control characteristics, it is necessary to improve

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