Photovoltaic grid-connected inverter comprising electric energy quality processing, and control method thereof

Abstract

The invention belongs to the field of photovoltaic power-grid generating, and specifically discloses a photovoltaic grid-connected inverter comprising electric energy quality processing, and a control method thereof. The photovoltaic grid-connected inverter comprises a photovoltaic assembly PV, an energy storage capacitor C, an inverter and a digital signal processor (DSP), wherein the DSP internally comprises a PI adjuster, a phase-locked loop module (PLL) and a hysteresis comparator, the photovoltaic assembly PV and the energy storage capacitor C are connected with the DC side of the inverter, the AC side of the inverter is connected with a power network through a filtering inductor, and the DSP samples capacitance and voltages of the DC side and power network voltages and currents of the AC side in real time. According to the invention, a dual-hysteresis SVPWM is employed, when error currents are quite large, single-hysteresis control is employed, and errors are rapidly reduced; and when the error currents are quite small, hysteresis SVPWM control is employed, space areas of error current and reference voltage vectors are detected in real time, while control precision is ensured, only signals of one group of legs of the inverter are changed in a switching process of an output voltage vector, and the switch frequency is reduced.

Description

technical field [0001] The invention belongs to the field of photovoltaic grid-connected power generation, and specifically relates to a photovoltaic grid-connected inverter including power quality processing and a control method thereof. Background technique [0002] With the deteriorating ecological environment, photovoltaic grid-connected power generation has become a power generation method with great potential; on the other hand, with the extensive application of nonlinear equipment, power quality problems have become an urgent problem to be solved. Photovoltaic grid-connected devices and power quality processing devices (active power filters) both face the problems of high cost and low device utilization in the development process. Existing grid-connected inverter control methods usually use a single hysteresis or a single SVPWM control method. The frequencies of the harmonic reactive power command and the photovoltaic grid-connected current command are different, and...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the problem of single control method of photovoltaic grid-connected inverter including power quality processing, the present invention provides a photovoltaic grid-connected inverter including power quality processing and its control method

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