Power conversion system and method for controlling power conversion system

A control method of a power conversion system that controls a power converter by model predictive control, the method comprising:

• by a higher control unit,
• generating a command current based on a command value;
• by a model predictive control unit,
• setting a plurality of assumed voltage vectors, which are assumed for vectors expressed by combination of an output voltage of each phase of the power converter, for each switching cycle of the output voltage;
• dividing the switching cycle of the output voltage into two periods according to a ratio between a dead time and the switching cycle of the output voltage;
• calculating a predicted current, which is a predicted value of an output current of the power converter, of the assumed voltage vector for each of the two periods obtained by the two-dividing;
• determining, based on the command current, an evaluation function between the assumed voltage vector and the predicted current;
• setting the assumed voltage vector or a combination of the assumed voltage vectors, each of which has highest evaluation function result, as a command voltage vector or a command voltage vector matrix;
• and
• outputting, based on the command voltage vector or the command voltage vector matrix, a gate signal for driving and controlling the power converter.