| 摘要 |
Included are a means for detecting a direct current output voltage, a direct current output current, or the like, in accordance with the status of a load of a resonant DC-DC converter and determines a control amount for controlling the turning on and off of switching elements, a frequency modulation control means for executing a frequency modulation control of the switching elements at a frequency lower than a resonance frequency based on the control amount, a means for executing a fixed frequency control of the switching elements at a frequency in the vicinity of the resonance frequency based on the control amount, and a pulse distribution means for generating drive pulses of the switching elements based on an output of each control means. The invention is such that when the direct current output voltage of the converter is of a value such that exceeds the maximum value that can be output in a fixed frequency control region, there is a switch from fixed frequency control to frequency modulation control. Because of this, conduction loss and turn-off loss caused by backflow current among the semiconductor switching elements are reduced, power conversion efficiency is improved, and the range of voltage that can be output by the resonant DC-DC converter is expanded. |
