Abstract: A power semiconductor module, a snubber circuit for the power semiconductor module, and induction heating power supply apparatus having the power semiconductor module are provided. The power semiconductor module includes a power semiconductor device configured to perform a switching operation, a casing inside which the power semiconductor device is provided, a control circuit board provided on top of an upper surface of the casing, a control terminal for the power semiconductor device being provided on the upper surface of the casing and connected to the control circuit board, and a shield plate disposed between the control circuit board and the upper surface of the casing to cover the upper surface of the casing and to cover at least one side surface of the casing.

Abstract: A spark plug having a resistor disposed between a metal terminal and a center electrode so as to be electrically connected to the metal terminal and the center electrode, wherein the resistor is in contact with an inner circumferential surface of the insulator. On a cross section taken along the axial line so as to include the axial line, in a case where a plurality of points are plotted at predetermined intervals in a direction of the axial line so as to be present on a partial boundary line, within an arbitrary range in the direction of the axial line, of a boundary line between the insulator and the resistor, and a regression line is drawn by a least-squares method with use of the plurality of points, an average value of distances in a direction perpendicular to the regression line between the regression line and the partial boundary line is 0.1 to 0.3 ?m.

Abstract: Disclosed is a spark plug including: an insulator having an axial hole formed along an axis of the spark plug; a center electrode disposed in a front end side of the axial hole; and a metal shell fixed around an outer circumference of the insulator, with a front end portion of the insulator protruding frontward from a front end of the metal shell. The front end portion of the insulator consists only of a first section and a second section located adjacent to and frontward of the first section and having an inner diameter larger than that of the first section. The second section has a chamfered area formed on an inner circumferential surface thereof so as to continue to a front end of the insulator.

Abstract: Provided is a spark plug capable of ensuring fouling resistance with a simple configuration. An insulator includes a step portion formed on an outer circumferential surface thereof. A center electrode is arranged in an axial hole of the insulator. A cylindrical metal shell having a shelf portion formed on an inner circumferential surface thereof is arranged radially outside the insulator. The insulator further includes a front end portion located frontward of the step portion. An outer circumferential surface of the front end portion has an arithmetic average roughness of 0.5 ?m or smaller in a circumferential direction. A recess is formed with a depth of 3 to 20 ?m in at least part of an end surface and the outer circumferential surface of the front end portion so as to extend from the front toward the rear.

Abstract: A spark plug having a resistor disposed between a metal terminal and a center electrode so as to be electrically connected to the metal terminal and the center electrode, wherein the resistor is in contact with an inner circumferential surface of the insulator. On a cross section taken along the axial line so as to include the axial line, in a case where a plurality of points are plotted at predetermined intervals in a direction of the axial line so as to be present on a partial boundary line, within an arbitrary range in the direction of the axial line, of a boundary line between the insulator and the resistor, and a regression line is drawn by a least-squares method with use of the plurality of points, an average value of distances in a direction perpendicular to the regression line between the regression line and the partial boundary line is 0.1 to 0.3 ?m.

Abstract: A power conversion apparatus and a power conversion method are provided for heat treatment. The power conversion apparatus includes a rectifier configured to convert AC power to DC power, a smoothing filter configured to control the DC power received from the rectifier to be constant, an inverter configured to convert the DC power received from the smoothing filer into high-frequency power by turning the DC power on and off using a switching device made of an SiC semiconductor, and a control unit configured to control the rectifier and the inverter. A rating of output power output from the inverter is determined in accordance with a frequency of the high-frequency power output from the inverter, a current-applying time, and an operation rate obtained by dividing the current-applying time by a sum of the current-applying time and a non-current-applying time.

Abstract: Disclosed is a spark plug including: an insulator having an axial hole formed along an axis of the spark plug; a center electrode disposed in a front end side of the axial hole; and a metal shell fixed around an outer circumference of the insulator, with a front end portion of the insulator protruding frontward from a front end of the metal shell. The front end portion of the insulator consists only of a first section and a second section located adjacent to and frontward of the first section and having an inner diameter larger than that of the first section. The second section has a chamfered area formed on an inner circumferential surface thereof so as to continue to a front end of the insulator.

Abstract: An induction heating power supply apparatus includes a smoothing section to smooth pulsating current of DC power output from a DC power supply section, and an inverter to convert the DC power smoothed by the smoothing section to AC power. The smoothing section includes a pair of bus bars connected to the inverter and a capacitor connected to the pair of bus bars. Each of the bus bars has an external surface extending in a current flow direction, the external surface including a flat face having a larger surface dimension than another face of the external surface in a direction perpendicular to the current flow direction. The bus bars are arranged in a layered manner such that the flat faces of the bus bars are opposed to each other and such that an insulator is sandwiched between the flat faces of the bus bars.

Abstract: An induction heating, power supply apparatus includes a smoothing section to smooth DC power and an inverter section to convert the smoothed DC power into AC power, The inverter section has first and second modules, each having serially connected switching devices. Output bus bars are interposed between the first and second modules. The smoothing section has first bus bars connected to a DC power supply section and the first module, a capacitor connected to the first bus bars, second bus bars connected to the DC power supply section and the second module, and another capacitor connected to the second bus bars. The first and second bus bars extend parallel to the output bus bars. The first module is interposed between the first bus bars and the output bus bars. The second module is interposed between the second bus bars and the output bus bars.

Abstract: The spark plug includes an insulator formed of an alumina-based sintered body, and the insulator contains Si, B a, and a rare earth element. In an analysis of the insulator by using a scanning transmission electron microscope having an electron-probe diameter of 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, a content of an alkaline earth metal is less than a detection limit at the crystal grain boundary, and a diffraction spot is present in an electron diffraction pattern of a portion where Ba is detected.

Abstract: The spark plug includes an insulator made from an alumina-based sintered body, and the insulator contains 90 to 98 wt % of an Al component in oxide equivalent. The insulator contains 1 to 5 wt % of an Si component, 0.1 to 1 wt % of an Mg component, 2 wt % or less of a Ca component, 0.3 to 6 wt % of a Ba component, and 0.11 to 5 wt % of a rare earth component, in oxide equivalent. In analysis using a scanning transmission electron microscope with a probe diameter of an electron beam set at 1 nm, Si and a rare earth element are detected at a crystal grain boundary having a thickness of 15 nm or less, and an alkaline earth metal at the crystal grain boundary is less than a detection limit.

Abstract: A spark plug having a center electrode that is formed by joining a conductive portion made of a conductive material and an insulating portion made of an insulating material. A sealing member electrically connects the conductive portion to a resistor. The insulating portion includes a protruding portion at a location on the back side of a back end of the sealing member. The protruding portion is embedded in the resistor.

Abstract: Disclosed is a spark plug capable of suppressing high-frequency noise by improving the material of an electrical connection part between a center electrode and a metal terminal within an axial hole of an insulator. A spark plug has an electrical connection part arranged in an axial hole of an insulator to establish electrical connection between a center electrode and a metal terminal. The electrical connection part includes a conductor having a first crystal phase formed of a Fe-containing oxide and a second crystal phase formed of a conductive metal oxide of perovskite crystal structure.

Abstract: A spark plug having a center electrode that is formed by joining a conductive portion made of a conductive material and an insulating portion made of an insulating material. A sealing member electrically connects the conductive portion to a resistor. The insulating portion includes a protruding portion at a location on the back side of a back end of the sealing member. The protruding portion is embedded in the resistor.

Abstract: A spark plug having an insulator that includes a first portion which accommodates a front end of the metallic terminal. A portion of the metallic terminal has a roughened surface portion with a Vickers hardness of 200 Hv or greater and 320 Hv or smaller. A first ratio of an outside diameter of the roughened surface corresponding to at least a part of the first portion of the insulator to the first bore diameter of the insulator is 0.90 or greater. A second ratio of the first bore diameter to the second bore diameter of the insulator is 0.80 or greater and 0.98 or smaller.

Abstract: A power conversion apparatus and a power conversion method are provided for heat treatment. The power conversion apparatus includes a rectifier configured to convert AC power to DC power, a smoothing filter configured to control the DC power received from the rectifier to be constant, an inverter configured to covert the DC power received from the smoothing filer into high-frequency power by turning the DC power on and off using a switching device made of an SiC semiconductor, and a control unit configured to control the rectifier and the inverter. A rating of output power output from the inverter is determined in accordance with a frequency of the high-frequency power output from the inverter, a current-applying time, and an operation rate obtained by dividing the current-applying time by a sum of the current-applying time and a non-current-applying time.

Abstract: A power supply apparatus for induction heating is provided. The power supply apparatus includes a smoothing filter configured to smooth a pulsating current of DC power output from a DC power supply, and an inverter configured to convert the DC power that has been smoothed by the smoothing filter into AC power. The smoothing filter includes a plurality of capacitors having different internal inductances and connected to each other in parallel between input terminals of the inverter, each of the capacitors being connected to the input terminals of the inverter directly or through a pair of bus bars. The plurality of capacitors includes a first capacitor and a second capacitor, the first capacitor having smaller internal inductance than the second capacitor and a shorter conductive path between the input terminals of the inverter than the second capacitor.

Abstract: A spark plug includes an insulator, a center electrode, a metallic shell, and a ground electrode. The insulator contains not less than 90.0 mass % and not greater than 98.1 mass % of Al2O3 with respect to a total mass of elements, as reduced to oxides, contained in the insulator, and has a porosity not greater than 5%. Assuming that a porosity of the insulator after a heat treatment is B, a difference (B?A) of the porosities before and after the heat treatment is not greater than 3.5%. In the heat treatment, the insulator is placed in a furnace, and a temperature in the furnace is increased from a room temperature to 1400° C. at a temperature increase rate of 7° C./min and is held at 1400° C. for 30 minutes, and thereafter, the temperature is decreased from 1400° C. to 400° C. at a temperature decrease rate of 10° C. or less per 5 minutes and is decreased to the room temperature.

Abstract: A spark plug having an insulator with a leg portion whose outer circumferential surface has an arithmetic mean roughness Ra of 0.5 ?m or less. The leg portion has a first section, a second section, and a third section. The first section has an outer diameter that decreases toward the forward end of the first section. The second section is located forward of and adjacent to the first section and its outer diameter decreases toward the forward end of the second section. The outer circumferential surface of the second section is located inward of a first straight line passing through the base and forward ends of the outer circumferential surface of the first section. The third section is located forward of and adjacent to the second section. The outer diameter of the third section is equal to or less than a forward end outer diameter Ds of the second section over the entire third section.

Abstract: A spark plug includes an insulator made of an alumina sintered body containing Al2O3 as a principal component and additional components including; an Si component, a Ba component, an Mg component, a Ca component, an Sr component, and a rare earth element component. When the additional components are expressed as oxides including RSiO2, RBaO, RMgO, RCaO, RSrO, and RRE2O3, contents (mass %) of the sub-component satisfy expressions (1) to (6) as follows: (1) 1.0?RSiO2?5.0; (2) 0.5?RBaO?5.0; (3) 0?RMgO?0.18; (4) 0?RMgO/RBaO?0.36; (5) 0.3?(RMgO+RCaO+RSrO)?1.8; and (6) 0?RRE2O3?0.1.