| 摘要 |
PROBLEM TO BE SOLVED: To stabilize a neutral point potential of a neutral point clamp type power conversion device over a range from a zero load current to a maximum load current.SOLUTION: A controller for the neutral point clamp type power conversion device comprises: three-phase/two-phase conversion means for converting a three-phase current flowing in a three-phase load that is driven by the neutral point clamp type power conversion device which is connected to a DC power source having three potentials and capable of three-level voltage output, into a d-axis current and a q-axis current of a rotation coordinate system; two-phase/three-phase current conversion means for converting a d-axis filter current and a q-axis filter current obtained by passing the d-axis current and the q-axis current through a filter of a time constant greater than an inverse of a fundamental frequency of the three-phase current into the three-phase current; and arithmetic means for calculating a zero-phase voltage command value for controlling a voltage obtained by dividing a DC input voltage at a neutral point of the power conversion device as a command value to be superposed on a three-phase voltage command value to the power conversion device on the basis of the three-phase current that is converted by the two-phase/three-phase current conversion means.SELECTED DRAWING: Figure 1 |
