method for controlling a three-phase threepoint wechselrichters.

摘要

A method of controlling a three-phase, three-level inverter comprises the steps of: judging whether the current of the output terminal of an inverter of the phase such that the electrical potential of the output terminal equals to the neutral-point terminal of the capacitor among three-output terminals of the inverter is in a positive direction in which current flows into a load connected to this output terminal or in a negative direction in which current flows from the load when another on/off mode having the same instantaneous space voltage vector as the instantaneous space voltage vector in a tentatively selected on/off mode exists; actually selecting the tentatively selected on/off mode if the result of the judgment is positive and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of the judgment is negative in the case where the electrical potential of the neutral-point terminal of the capacitor is above a preset upper-limit value; and actually selecting the tentatively selected on/off mode if the result of the judgment is negative and actually selecting another on/off mode instead of the tentatively selected on/off mode when the result of the judgment is positive in the case where the electrical potential of the neutral-point terminal of the capacitor is below a preset lower-limit value. IMAGE