Frequency self-adaptive phase locking method based on three-phase energy storage inverter closed-loop system

Abstract

The invention discloses a frequency self-adaptive phase locking method based on a three-phase energy storage inverter closed-loop system, and aims to solve the problem that a deviation exists between a tracking angular frequency omega p and a mains supply positive sequence fundamental wave angular frequency omega, and the design of a low-pass filter is difficult. According to the invention, a specific fourth-order filter is added in a phase locking link, and meets the tracking requirement for commercial power frequency signals, and omega 0 in the fourth-order filter is updated on the basis of the phase locking angular frequency obtained through phase locking of the previous commercial power period, so that sine and cosine functions obtained through closed-loop sampling in the current commercial power period pass through the fourth-order filter respectively, whether signals of the sine and cosine functions are attenuated or not is checked, and omega d output by a phase lock controller is compensated by adopting an integral controller according to the positive and negative deviations.

Description

technical field [0001] The invention relates to the field of automatic phase control, in particular to a frequency adaptive phase-locking method based on a closed-loop system of a three-phase energy storage inverter. Background technique [0002] In a local microgrid containing wind power, solar energy, and energy storage equipment, when these power generation equipment are connected to the grid for power generation, due to the use of power electronic equipment switches and control accuracy, harmonic currents will inevitably be injected into the grid. If the microgrid When the medium power generation is too large, these harmonic currents injected into the grid will also increase the distortion rate of the microgrid voltage. Since three-phase grid-connected inverters such as energy storage and solar energy need to phase-lock the positive-sequence fundamental wave component of the mains voltage, the phase of the grid-connected current and the positive-sequence fundamental wave...

AI Technical Summary

Problems solved by technology

Since three-phase grid-connected inverters such as energy storage and solar energy need to phase-lock the positive-sequence fundamental wave component of the mains voltage, the phase of the grid-connected current and the positive-sequence fundamental wave component of the voltage are kept consistent. All the injection is active power, but after the mains voltage is distorted, the traditional zero-crossing sampling or the traditional three-phase closed-loop sampling will make the phase-locking inaccurate and the dynamic performance poor

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