Patent ID: 8872454

Claim:
A control unit of a rotary device, the control unit controlling a control amount of the rotary device by controlling on and off states of switching elements of a power converting circuit, the control amount being at least one of an electric current flowing in the rotary device, a torque of the rotary device, and a magnetic flux of the rotary device, the switching elements connecting and disconnecting between a voltage applying unit having multiple different voltage values and terminals of the rotary device, the control unit comprising: a relative rate predicting section that is configured to: temporarily set operation states for a next control cycle of the power converting circuit, each of the temporarily set operation states being indicated by a voltage vector defined by the on and off states of the switching elements and having a switching phase number of equal to or less than two from a current operation state of the power converting circuit as operation states for a next control cycle, and predict relative rates each defined based on a difference between a first change rate and a second change rate, the first change rate being a rate of change of a command value of the control amount in one control cycle, the second change rate being a rate of change of the control amount in one control cycle predicted according to each temporarily set operation state; a determining section that is configured to: evaluate the temporarily set operation states with regard to an absolute value of the relative rate so that the temporarily set operation state indicating a smallest absolute value of the relative rate has a highest evaluation rate, and determine the temporarily set operation state indicating the highest evaluation rate as an operation state of the power converting circuit; and an operating section configured to operate the power converting circuit to the operation state determined by the determining section.