System and method for operating power converters

An electrical circuit for a multilevel power converter, said electrical circuit comprising:

• a plurality of electrically conductive elements configured substantially parallel to each other;
• a plurality of switching devices, each switching device of said plurality of switching devices coupled to one electrically conductive element of said plurality of electrically conductive elements;
• a plurality of flying capacitors coupled to each of two adjacent electrically conductive elements of said plurality of electrically conductive elements;
• at least one alternating current (AC) terminal;
• and
• a processing device comprising a model of said electrical circuit resident thereon, said processing device configured to:
• select, at least partially based on said model of said electrical circuit, at least one possible switching state of said electrical circuit from a plurality of possible switching states of said electrical circuit, wherein each possible switching state of said electrical circuit has a voltage level that at least partially corresponds to a commanded voltage level for said at least one AC terminal, and wherein each possible switching state of said electrical circuit defines a switching state of each switching device of said plurality of switching devices, wherein each switching state of said electrical circuit has a corresponding charging state of said electrical circuit;
• select, at least partially based on said model of said electrical circuit and at least partially based on the selected possible switching state of said electrical circuit, a possible charging state of said electrical circuit, wherein each possible charging state of said electrical circuit defines a charging state of each flying capacitor of said plurality of flying capacitors, and wherein selecting a possible charging state of said electrical circuit comprises resolving conflicting charging states of said each flying capacitor of said plurality of flying capacitors and selecting a switching state corresponding to the commanded voltage level;
• and
• set the switching state of said electrical circuit at least partially based on the selected charging state of said electrical circuit.

An electric power system comprising:

• an alternating current (AC) source;
• a direct current (DC) link;
• and
• a multilevel power converter comprising an electrical circuit extending between said AC source and said DC link, said electrical circuit comprising:
• a plurality of electrically conductive elements configured substantially parallel to each other;
• a plurality of switching devices, each switching device of said plurality of switching devices coupled to one electrically conductive element of said plurality of electrically conductive elements;
• a plurality of flying capacitors coupled to each of two adjacent electrically conductive elements of said plurality of electrically conductive elements;
• at least one AC terminal;
• and
• a processing device comprising a model of said electrical circuit resident thereon, said processing device configured to:
• select, at least partially based on said model of said electrical circuit, at least one possible switching state of said electrical circuit from a plurality of possible switching states of said electrical circuit, wherein each possible switching state of said electrical circuit has a voltage level that at least partially corresponds to a commanded voltage level for said at least one AC terminal, and wherein each possible switching state of said electrical circuit defines a switching state of each switching device of said plurality of switching devices, wherein each switching state of said electrical circuit has a corresponding charging state of said electrical circuit;
• select, at least partially based on said model of said electrical circuit and at least partially based on the selected possible switching state of said electrical circuit, a possible charging state of said electrical circuit, wherein each possible charging state of said electrical circuit defines a charging state of each flying capacitor of said plurality of flying capacitors, and wherein selecting a possible charging state of said electrical circuit comprises resolving conflicting charging states of said each flying capacitor of said plurality of flying capacitors and selecting a switching state corresponding to the commanded voltage level;
• and
• set the switching state of said electrical circuit at least partially based on the selected charging state of said electrical circuit.