DC POWER SOURCE DEVICE, ELECTRIC MOTOR DRIVE DEVICE, AIR CONDITIONER, AND REFRIGERATOR

摘要

A direct-current power supply device includes a switching unit 7 constituted by a first switching element 4a and a second switching element 4b and a control unit 8 that controls the operations of the first witching element 4a and the second switching element 4b. The switching unit 7 has a first mode in which on-duty is a first value and a second mode in which the on-duty is a second value larger than the first value. When transitioning the switching unit 7 from the first mode to the second mode, the control unit 8 controls the switching unit 7 such that the time until the on-duty reaches the second value is equal to or longer than a fixed time and controls, after the on-duty reaches the second value, an operation cycle of the switching unit 7 to extend the operation cycle.