DEVICE FOR CONTROLLING THREE-LEVEL INVERTER

摘要

PROBLEM TO BE SOLVED: To provide a device for controlling a three-level inverter which suppresses an imbalance in neutral potential irrespective of the power factor of an inverter output current and of whether there is a fundamental, and suppresses an increase in computational load and an increase in the number of components.;SOLUTION: A zero-phase voltage calculation section 11 calculates a zero-phase voltage on the basis of a deviation between neutral potentials Vdc1, Vdc2, and adders 15 add the zero-phase voltage to voltage command values Vu^*, Vv^*, Vw^* to calculate corrected voltage command values Vu^*', Vv^*', Vw^*'. A neutral current estimation circuit 2 estimates neutral currents of phases, and a sign determination section 20 determines the sign of the zero-phase voltage added to the voltage command values Vu^*, Vv^*, Vw^* on the basis of the sign of the voltage command value Vu^*, Vv^*, Vw^* and the sign of an inverter output current detection value Iinvu, Iinvv, Iinvw, the values in a phase that has the largest absolute value of the estimated neutral current.;COPYRIGHT: (C)2014,JPO&INPIT