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: A power converter includes a first electric power conversion unit having an inverter for converting a first DC electric power to an AC electric power, an AC circuit connected to the first electric power conversion means; a second electric power conversion unit for receiving the first DC electric power and converting the same to a second DC electric power having a voltage level that differs from the voltage level of the first DC electric power, a power storage unit for storing the second DC electric power of the second electric power conversion unit; and a ripple suppressor having a first inductance for guiding the second DC electric power of the second electric power conversion unit to the power storage means and a second inductance for suppressing the ripple component included in the second DC electric power arranged between the second electric power conversion unit and the power storage unit.

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: 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: A power converter includes a first electric power conversion unit having an inverter for converting a first DC electric power to an AC electric power, an AC circuit connected to the first electric power conversion means; a second electric power conversion unit for receiving the first DC electric power and converting the same to a second DC electric power having a voltage level that differs from the voltage level of the first DC electric power, a power storage unit for storing the second DC electric power of the second electric power conversion unit; and a ripple suppressor having a first inductance for guiding the second DC electric power of the second electric power conversion unit to the power storage means and a second inductance for suppressing the ripple component included in the second DC electric power arranged between the second electric power conversion unit and the power storage unit.