Unbalanced voltage compensation method, the unbalanced voltage compensation device, a control method of a three-phase converter, and a three-phase converter of the controller

摘要

PROBLEM TO BE SOLVED: To derive an instantaneous value of a Y-phase voltage of a Y-connection mutually having a phase difference of 120 degrees from the instantaneous value of a line voltage in the three-phase AC unbalanced voltage compensation.;SOLUTION: The instantaneous values of a three-phase unbalanced voltage and a zero-phase voltage of the Y-phase voltage mutually having a phase difference of 120 degrees are derived from the instantaneous value of the three-phase unbalanced voltage of the line voltage by using the three-phase unbalanced line voltage in a general three-phase distribution system as an object and employing a conversion method from the line voltage to the Y-phase voltage by a gravity vector operation. Power conversion, in which PWM conversion is applied to a three-phase AC voltage to output a DC voltage, includes a gravity vector operation process for finding the Y-phase voltage mutually having a phase difference of 120 degrees from each line voltage, a symmetrical component calculation process for calculating a symmetrical component voltage in a three-phase balanced system from the Y-phase voltage found in the gravity vector operation process, and an unbalanced voltage compensation process for forming a compensation signal to compensate the unbalanced voltage of the three-phase AC voltage and generating a control signal for outputting the DC voltage by applying the PWM conversion of the three-phase AC voltage.;COPYRIGHT: (C)2011,JPO&INPIT