Patent ID: 8866435

Claim:
A control device for a power control unit controlling electric power transmitted and received between a motor and a power supply, said power control unit including at least one switching element and converting electric power by turning said switching element on and off, said control device comprising: a first control unit controlling said switching element to be turned on and off based on comparison between a carrier signal and a control command; and a second control unit controlling a frequency of said carrier signal, said second control unit setting a frequency range in accordance with a rotation speed of said motor, and causing the frequency of said carrier signal to fluctuate within said frequency range, and a lower limit value of said frequency range being set at a value that is greater as the rotation speed of said motor becomes higher; wherein said lower limit value is set at zero in a region where the rotation speed of said motor is lower than a prescribed speed, and set at a value that is greater as the rotation speed of said motor is higher in a region where the rotation speed of said motor exceeds said prescribed speed.