Control apparatus for three-level inverter and program

A non-transitory computer-readable storage medium storing therein a program applicable to a system,

• the system comprising
• a first power storage unit and a second power storage unit connected in series,
• a rotating electric machine including armature windings for three phases,
• a three-level inverter including, in the respective phases, switches that electrically connect the armature winding to any of a positive electrode side of the first power storage unit, a neutral point between a negative electrode side of the first power storage unit and a positive electrode side of the second power storage unit, and a negative electrode side of the second power storage unit, and
• a computer, the program causing the computer to implement switching control of the switches, wherein:
• the program causes the computer to implement a process comprising:
• a setting step of setting a drive pattern composed of a combination of drive states of the switches and occurrence periods of the drive states, based on a command voltage for controlling a controlled variable of the rotating electric machine to a command value;
• and
• a control step of performing the switching control based on the set drive pattern and occurrence periods of the drive states;
• three differing drive states in which the armature winding of the respective phases is electrically connected to the positive electrode side of the first power storage unit, the neutral point, or the negative electrode side of the second power storage unit are zero-voltage drive states;
• the setting step comprises
• setting the drive pattern to include at least two of the zero-voltage drive states;
• and
• the control step comprises
• adjusting the occurrence periods of the zero-voltage drive states included in the drive pattern in the switching control.