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Mitsuaki Hirakawa

Mitsuaki Hirakawa, Saitama JP

Patent application numberDescriptionPublished
20080211316Electric power converter - The invention provides an optimal electric power converter for a DC/DC converter which variably steps up a voltage successively with an optional magnification of one to two times or more and/or step down a voltage successively with a step-down ratio of one time or less. The converter includes a first input-output part, an inductor connected with a positive or a negative electrode side of the first input-output part, plural switches, plural capacitors, a second input-output part connected with plural capacitors, and a control circuit, wherein the control circuit controls the plural switches with operation mode and makes the inductor and plural capacitors selectively functional, wherein the electric power converter is of a switched capacitance type that performs any operation out of step-up, step-down, regeneration, and continuity, and wherein the control circuit controls to have a period for which two switches out of the plural switches are simultaneously turned ON.09-04-2008
20090267718Magnetic-field cancellation type transformer - A magnetic-filed cancellation type transformer includes a primary winding wire and a secondary winding wire which generate magnetic flux when energized, and a core constituted by a magnetic leg portion about which the primary winding wire and the secondary winding wire are wound, and a base for fixing the magnetic leg portion. The primary winding wire and the secondary winding wire are alternately piled and wound on the magnetic leg portion, so that the direction of magnetic flux generated from the primary winding wire and the secondary winding wire are opposite to each other in any couple selected from among the pieces of magnetic flux, and the magnetic flux is cancelled out with each other.10-29-2009
20090289751Composite transformer and power converter using same - A composite transformer, having first and second inductors and a transformer, includes a transformer core that has a core leg around which portions of first and second windings are wound, and a base fixing the core leg, a first inductor core that has a core leg around which a portion of the first winding is wound and a base fixing the core leg, and a second inductor core that has a core leg around which a portion of the second winding is wound and a base fixing the core leg. The first and second windings are wound in a manner that flux are cancelled with each other, and are wound around the core leg of the transformer core in a manner alternately overlapping with each other, and are wound around respective core legs of the first and second inductor cores so as to be apart from each other to suppress any interference of magnetic fluxes.11-26-2009
20100066341POWER CONVERTER - A power converter includes an input unit, an output unit, first and second capacitors connected in series, a first electric conduction control device, a second electric conduction control device, a third electric conduction control device, and a fourth electric conduction control device, and a control circuit for performing on/off control on those electric conduction control devices. The first electric conduction control device and the fourth electric conduction control device have a first path through which a current flowing between the input unit and the output unit is allowed to flow in one direction, and a second path which has a switch function of allowing the current flowing between the input unit and the output unit to flow through or shutting off such a current.03-18-2010
20100320994MULTI-PARALLEL MAGNETIC-FIELD CANCELLATION TYPE TRANSFORMER - A multi-parallel magnetic-filed cancellation type transformer includes a plurality of coils which generate magnetic flux during energization and a core having a plurality of magnetic leg portions on which the coils are wound, and bases for fixing the magnetic leg portions. The plurality of coils are wound on the magnetic leg portions in such a manner that the magnetic flux generated from the coils are formed in the directions opposite to each other. A plurality of closed magnetic circuits of the magnetic flux are formed at the magnetic leg portions and the bases. The magnetic resistance of the closed magnetic circuits is homogeneous. Accordingly, the transformer can reduce the size thereof, and prevent the deterioration of electric power conversion efficiency.12-23-2010
20110032733DC-DC CONVERTER AND POWER SUPPLYING SYSTEM INCLUDING SAME - A DC-DC converter has a first-voltage-side port, a second-voltage-side port, and a third-voltage-side port, and performs, at different timings, an operation of boosting a first voltage to a third voltage and an operation of bucking a second voltage to the third voltage. A power supplying system includes a fuel cell, a secondary battery, an accessory system, the DC-DC converter, and another DC-DC converter connected between the fuel cell and a motor, and boosting the first voltage of the fuel cell to a fourth voltage to supply power to the motor through an inverter. The former DC-DC converter has the first-voltage-side port connected to the fuel cell, has the second-voltage-side port connected to the secondary battery, and has the third-voltage-side port connected to the accessory system.02-10-2011

Patent applications by Mitsuaki Hirakawa, Saitama JP

Mitsuaki Hirakawa, Satama JP

Patent application numberDescriptionPublished
20080238383Power converter and multiport power converter - The DC/DC converter is that which is constituted so as to have a failure detecting circuit in which a first capacitor and a second capacitor are connected in series, a plurality of switches are switched according to a predetermined operating mode to select an inductor, the first capacitor and the second capacitor, allowing them to function, thereby performing any one of the boost, buck, and conducting operations of input voltage.10-02-2008