Controller for a rotating electrical machine

摘要

To minimize switching losses in a rotating electrical machine, exemplary embodiments of the present disclosure proposes an iterative control method which calculates optimal switching states in advance. A rotating electrical machine can be controlled on the basis of this iterative control method.

主权项

1. A method for operating a rotating electrical machine,
wherein the rotating electrical machine is supplied with electric current by a converter from a DC voltage circuit via at least one phase, and the converter is configured to switch the at least one phase to at least two voltage levels, wherein the method comprises: generating switching sequences, wherein each switching sequence comprises a series of switching transitions of the converter with a first switching transition; evaluating each of the switching sequences with a quality value; selecting the switching sequence with a minimum quality value; driving switching elements of the converter with the first switching transition of the selected switching sequence as the selected switching transition, so that at least one phase is switched to a voltage level which corresponds to the selected switching transition; wherein the switching sequences are generated as follows: (a) a switching sequence of a first length is generated from a switching sequence of a second length smaller than the first length, wherein at least one possible switching transition is attached to the switching sequence of the second length, and a first switching sequence with a preselected switching transition is initialized; (b) output variables of the electrical machine are calculated for the switching sequence of the first length on the basis of the switching transitions of the switching sequence of the first length; (c) the switching sequence of the first length is rejected if calculated output variables are not within predefined limits and/or calculated output variables become removed from a predefined limit as the time increases; and further switching sequences are generated iteratively from the unrejected switching sequence in accordance with steps (a) to (c), and wherein the method comprises: calculating a lower limit for quality values based on previously calculated quality values of complete switching sequences; and rejecting switching sequences whose quality value exceeds the lower limit for quality values.