Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: A transformer includes a first core, a first primary coil, a first secondary coil, and a first insulating member. The first secondary coil includes a second conductor wound around the first core. The first insulating member covers the first secondary coil. The second conductor has a shape of a first polygon in a cross-section of the second conductor. A first corner of the first polygon has a first radius of curvature of 0.1 mm or more. The transformer thus has improved dielectric breakdown voltage and improved power efficiency.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, and capacitors. When detecting a malfunction in semiconductor switching elements, a control circuit halts a normal operation mode and controls the first switching circuit by a protection mode for turning OFF all the semiconductor switching elements, and controls the second switching circuit by a bypass mode for bypassing the capacitor by turning ON the semiconductor switching elements in a discharge leg and causing a short circuit between the secondary side terminals, after controlling the second switching circuit by a discharge mode for discharging the capacitor by turning ON the semiconductor switching element in a discharge leg.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, and capacitors. When detecting a malfunction in semiconductor switching elements, a control circuit halts a normal operation mode and controls the first switching circuit by a protection mode for turning OFF all the semiconductor switching elements, and controls the second switching circuit by a bypass mode for bypassing the capacitor by turning ON the semiconductor switching elements in a discharge leg and causing a short circuit between the secondary side terminals, after controlling the second switching circuit by a discharge mode for discharging the capacitor by turning ON the semiconductor switching element in a discharge leg.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, capacitors, a discharge circuit connected in parallel to the secondary side capacitor, and a bypass switch for bypassing the capacitor. When detecting a malfunction in semiconductor switching elements, a control circuit turns OFF all of the semiconductor switching elements, and controls the bypass switch after discharge of the capacitor through the discharge circuit, so that the capacitor is bypassed.

Abstract: Each DC/DC converter includes a transformer, first and second switching circuits each formed of a plurality of legs having a plurality of semiconductor switching elements, capacitors, a discharge circuit connected in parallel to the secondary side capacitor, and a bypass switch for bypassing the capacitor. When detecting a malfunction in semiconductor switching elements, a control circuit turns OFF all of the semiconductor switching elements, and controls the bypass switch after discharge of the capacitor through the discharge circuit, so that the capacitor is bypassed.