Abstract: A vehicle control apparatus includes: a follow-up-running control portion configured to execute a follow-up running control for causing a vehicle to run following a preceding vehicle with a target inter-vehicle distance; and a shift control portion configured to change a gear ratio of an automatic transmission in accordance with a predetermined shifting condition. The shift control portion is configured to set a high fluid-temperature determination value, based on information relating to the preceding vehicle that affects an air flow rate. When a fluid temperature of the automatic transmission is not lower than the high fluid-temperature determination value, the shift control portion is configured to change the shifting condition such that a higher-speed gear position making the gear ratio lower is more frequently established in the automatic transmission than when the fluid temperature of the automatic transmission is lower than the high fluid-temperature determination value.

Abstract: A DC power supply including a resonant circuit on a secondary side of a transformer suppresses a surge voltage during power recovery of diodes constituting a rectifier circuit, correctly estimates a load current from a secondary current of the transformer, and adjusts supplied power when a load is light. The DC power supply includes a DC voltage source, a converter, a transformer, a rectifier circuit, a resonant circuit composed of a resonant switch and a resonant capacitor, a filter reactor, a filter capacitor, a snubber diode, a snubber capacitor, a load, first and second voltage sensors, a current sensor, and a controller for controlling gate pulses of semiconductor devices constituting a converter and the resonant switch and a signal for adjusting operation timings of A/D converters converting the signals of these sensors.

Abstract: Semiconductor element groups constituting a unit are mounted on a cooler heat receiving part 1 on the same plane and are adapted to radiate heat by self-cooling or cooling by wind. First and fourth semiconductor elements Q1, Q4 are arranged on the lower side of the cooler heat receiving part, second and third semiconductor elements Q2, Q3 are arranged in the middle, a first diode D5 and a second diode D6 are arranged on the upper side, the first and second semiconductor elements Q1, Q2, as well as the third and fourth semiconductor elements Q3, Q4 are each arranged in positions opposite to each other in a horizontal direction with respect to a centerline of a cooler in a vertical direction.

Abstract: In a DC power supply in which a DC power source and a transformer are connected via a power conversion circuit and a secondary winding of the transformer is connected to a load via a rectifier diode bridge and a filter circuit to supply power to the load, a resonance reactor is provided on an output side of the transformer, a resonant switch circuit including a parallel circuit of a diode and a semiconductor switch and a resonant capacitor is connected in parallel to the rectifier diode bridge and a snubber circuit including a snubber capacitor, a snubber diode and a diode for discharge is connected to a serial resonant circuit including the resonance reactor and the resonant capacitor in the resonant switch circuit to absorb a surge voltage.

Abstract: A DC power supply including a resonant circuit on a secondary side of a transformer suppresses a surge voltage during power recovery of diodes constituting a rectifier circuit, correctly estimates a load current from a secondary current of the transformer, and adjusts supplied power when a load is light. The DC power supply includes a DC voltage source, a converter, a transformer, a rectifier circuit, a resonant circuit composed of a resonant switch and a resonant capacitor, a filter reactor, a filter capacitor, a snubber diode, a snubber capacitor, a load, first and second voltage sensors, a current sensor, and a controller for controlling gate pulses of semiconductor devices constituting a converter and the resonant switch and a signal for adjusting operation timings of A/D converters converting the signals of these sensors.

Abstract: In a DC power supply in which a DC power source and a transformer are connected via a power conversion circuit and a secondary winding of the transformer is connected to a load via a rectifier diode bridge and a filter circuit to supply power to the load, a resonance reactor is provided on an output side of the transformer, a resonant switch circuit including a parallel circuit of a diode and a semiconductor switch and a resonant capacitor is connected in parallel to the rectifier diode bridge and a snubber circuit including a snubber capacitor, a snubber diode and a diode for discharge is connected to a serial resonant circuit including the resonance reactor and the resonant capacitor in the resonant switch circuit to absorb a surge voltage.