Patent ID: 8780592
Filing Date: 2014-07-15
Classification: H02J,H02M,Y02E

Abstract:
1. A grid-interactive inverter configured to receive direct current and to provide alternating current to a utility grid, comprising: input terminals configured to receive a direct current; output terminals configured to provide an alternating output current to the utility grid; a controller; an output current sensor; a DC-AC inverter stage comprising a plurality of switches controlled by control signals generated by the controller; wherein the controller is configured to generate control signals that cause the switches in the DC-AC inverter stage to switch a direct current in a bidirectional manner across the output terminals to provide an initial alternating output current to the utility grid; wherein the controller is configured to measure the initial alternating output current provided to the utility grid using the output current sensor; wherein the controller is configured to perform frequency decomposition of the initial alternating output current to determine a magnitude for each of a plurality of unwanted frequency components corresponding to harmonics of a fundamental frequency that contribute to harmonic distortion in the initial alternating output current; and wherein the controller is configured to generate control signals that cause the switches in the DC-AC inverter stage to switch current in a bidirectional manner across the output terminals to provide a resulting alternating output current to the utility grid in a way that the magnitude determined for each of the plurality of unwanted frequency components is subtracted from the resulting alternating output current.