Abstract: An inverter unit of the invention converts a DC current to a high frequency AC current. The inverter unit is formed of a metal conductor base plate connected to a positive terminal of a DC power supply; and switching elements arranged on both surfaces of the base plate. Each switching element situated on each surface of the base plate includes an upper arm and a lower arm of the inverter unit to form an arm pair. The arm pairs formed on both surfaces of the base plate constitute a single phase bridge circuit.

Abstract: In a conductive contact structure for two conductors, a lower electrode also serves as a cooling element, and two grooves are formed in the lower surface of an electrode. A grease-like insulating material high in thermal conductivity is applied to the lower surface of the electrode except the middle region thereof which is defined by the two grooves; that is, it is applied only to the right and left regions of the lower surface which are located on both sides of the middle region. A pressurizing force is applied through an upper conductor to an electrode whose lower surface is fixed through an insulating board to the upper surface of the electrode. The middle region of the lower surface of the electrode is in contact with the surface of the lower conductor, and the right and left regions are elastically deformed in such a manner that they are slightly raised above the surface of the lower conductor, thus forming spaces therebetween. The spaces thus formed are filled with the insulating material.

Abstract: A connection structure for connecting a plurality of semiconductor switches in parallel includes a pressed contact for a semiconductor switch. The pressed contact includes a layered structure which connects a drain conductor to a plurality of drain electrodes, a source conductor to a plurality of source electrodes, a gate conductor to a plurality of gate electrodes, and an insulating film between the gate conductor and the source conductor. The gate electrodes are a plurality of resilient elastic wings which are pressed upward against the gate conductor, thereby ensuring a good electrical connection.