Energy storage inverter phase synchronization method based on half-angle characteristic

Abstract

The invention discloses an energy storage inverter phase synchronization method based on a half-angle characteristic, and the method comprises the steps: collecting an input voltage signal of a power grid, locking a phase angle of the input voltage signal through a rotation coordinate method, and obtaining a sine value and a cosine value of a rotation angle of the input voltage signal according to the phase angle of the input voltage signal; according to a half-angle characteristic formula, sine values and cosine values of the input voltage signal and the output voltage signal are converted into sine values and cosine values in a half-angle form; converting the sine value and the cosine value in the half-angle form into a sine value of a phase angle difference value of the input voltage signal and the output voltage signal according to a two-angle sum formula; and according to PI control, taking the sine value of the phase angle difference as an input quantity to regulate and control the phase of the output voltage signal. According to the invention, phase synchronization of the power grid before grid connection of the inverter is realized, the phase difference between the inverter synchronization signal and the power grid signal is reduced, the current generated due to the voltage difference during grid connection is reduced, and the stability of the inverter is improved.

Description

technical field [0001] The present application relates to the field of photovoltaic energy storage inverters, in particular to a method for phase synchronization of energy storage inverters based on half-angle characteristics. Background technique [0002] Photovoltaic energy storage inverters have the function of supplying power to the grid. How to track the accuracy of the grid phase under grid-connected conditions to reduce errors has become an important research topic. The traditional synchronous square wave method is that the inverter master uses the rotating coordinate method to track the grid voltage AC signal, marks the zero-crossing point of the sine value of the phase angle, and the slave constructs the phase and frequency of the output voltage signal according to the zero-crossing point. However, in the traditional phase synchronization method, the marked phase does not match the actual phase. This is because there are three zero-crossing points in one cycle of th...

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Problems solved by technology

However, in the traditional phase synchronization method, the marked phase does not match the actual phase. This is because there are three zero-crossing points in one cycle of the sine value of the AC signal, and two of the zero-crossing points need to be marked, and the processor is easy to cause errors. Judgment, so that the zero-crossing point of the mark can not reflect the phase and frequency of the AC signal, resulting in the error of the phase tracking of the grid, resulting in the inconsistency between the output voltage signal and the grid signal

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