Patent ID: 8750008

Claim:
A power supply device comprising: a multi-phase converter including first and second chopper circuits connected in parallel between a power supply line connected to a load and a power supply of direct current, said first chopper circuit including a first switching circuit and a first reactor disposed to pass electric current in response to operation of said first switching circuit, said second chopper circuit including a second switching circuit and a second reactor disposed to pass electric current in response to operation of said second switching circuit, said first reactor and said second reactor being arranged to be magnetically coupled to each other; a first sensor detecting a value of current flowing in said first reactor; and a second sensor detecting a value of current flowing in said second reactor; and a control circuit controlling, in a case of a low-temperature state in which a temperature of said power supply is lower than a predetermined value, said first and second chopper circuits so that a difference between the value of current flowing in said first reactor and the value of current flowing in said second reactor is increased relative to a case of a non-low-temperature state in which the temperature of said power supply higher than said predetermined value, to thereby increase a ripple component of current flowing in said power supply, said control circuit including: a setting unit setting a voltage command value for said power supply line based on an operating state of said load; and a control unit controlling said first chopper circuit in accordance with a result of a first calculation performed based on said voltage command value and the value detected by said first sensor and controlling said second chopper circuit in accordance with a result of a second calculation performed based on said voltage command value and the value detected by said second sensor, in a case of said low-temperature state, said control unit performing an offset process of adding a predetermined amount to the value detected by one of said first sensor and said second sensor to thereby increase a difference between the value of current flowing in said first reactor and the value of current flowing in said second reactor.