A system and method for suppressing half-cycle current distortion of a double-buck grid-connected inverter

Abstract

The invention discloses a half-period operating current distortion suppression system and method for a double-buck grid-connected inverter. The invention establishes that the buck unit works in the current continuous mode and the half-period working state of the buck unit in the dual-buck topology. The different intervals of the current discontinuous mode, and establish the corresponding relationship between the switching time of the continuous current mode and the discontinuous mode and the amplitude of the incoming current. In the discontinuous current mode, according to the nonlinear relationship between the voltage gain of the buck unit and the duty ratio, the output of the current loop regulator is corrected for the equivalent linearization of the modulated wave, so that the gain and the output of the regulator to the bridge arm voltage Consistent when the current is continuous. The invention reduces the current ripple and current conduction time by reducing the duty cycle, avoiding the current distortion problem caused by the inductor current ripple in the traditional control, so that the half-period working double-buck inverter is not only efficient and reliable, but also Realizing low harmonics of incoming grid current is more conducive to the application of dual-buck topology in grid-connected inverters.

Description

technical field [0001] The invention relates to the technical field of DC-AC grid-connected converters, in particular to a half-period current zero-crossing distortion suppression system and method applied in a double-buck grid-connected inverter. Background technique [0002] Global energy consumption is increasing year by year. Traditional fossil energy is increasingly depleted, and at the same time it brings serious environmental pollution problems. New energy power generation has become an important way to solve this problem. Distributed power generation systems relying on wind energy, solar energy and other new energy sources occupy an increasingly important position in the AC power grid. New energy has the characteristics of decentralization, time-sharing, regionality, and greater influence by natural conditions. The micro-grid structure with new energy power generation as the main body and interacting with the large power grid has attracted widespread attention in rec...

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Problems solved by technology

Current distortion will also cause the effective value of the current to increase, increasing the loss of switching devices and magnetic devices

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