The semiconductor device according to the present invention includes a semiconductor module, a cooling member, and a heat transfer member. The semiconductor module includes a switching element and a diode connected in antiparallel to each other. The heat transfer member is disposed between the semiconductor module and the cooling member so as to transfer heat generated by the switching element and the diode to the cooling member. The heat transfer member has a mounting surface on which the switching element and the diode are mounted side by side and a surface which is opposite to the mounting surface and is disposed in contact with the cooling member. In the heat transfer member, the thermal conductivity in a first direction parallel to the mounting surface is higher than the thermal conductivity in a second direction perpendicular to the mounting surface.

The semiconductor device according to the present invention includes a semiconductor module, a cooling member, and a heat transfer member. The semiconductor module includes a switching element and a diode connected in antiparallel to each other. The heat transfer member is disposed between the semiconductor module and the cooling member so as to transfer heat generated by the switching element and the diode to the cooling member. The heat transfer member has a mounting surface on which the switching element and the diode are mounted side by side and a surface which is opposite to the mounting surface and is disposed in contact with the cooling member. In the heat transfer member, the thermal conductivity in a first direction parallel to the mounting surface is higher than the thermal conductivity in a second direction perpendicular to the mounting surface.

An electrical wiring device for delivering power to multiple mobile devices including: a housing having a faceplate; a first power delivery port accessible through the faceplate; a second power delivery accessible through the faceplate; an AC/DC converter disposed in the housing and configured to receive an AC signal from a connection to a source of AC mains power and to output a DC signal; a first DC/DC converter disposed in the housing and configured to receive the DC signal and provide a first DC output signal having a first power to a first power delivery port; a second DC/DC converter disposed in the housing and configured to receive the DC signal and provide a second DC output signal having a second power to a second power delivery port; wherein the first DC output signal is different from the second DC output signal.

An electrical wiring device for delivering power to multiple mobile devices including: a housing having a faceplate; a first power delivery port accessible through the faceplate; a second power delivery accessible through the faceplate; an AC/DC converter disposed in the housing and configured to receive an AC signal from a connection to a source of AC mains power and to output a DC signal; a first DC/DC converter disposed in the housing and configured to receive the DC signal and provide a first DC output signal having a first power to a first power delivery port; a second DC/DC converter disposed in the housing and configured to receive the DC signal and provide a second DC output signal having a second power to a second power delivery port; wherein the first DC output signal is different from the second DC output signal.

A switching control circuit for controlling a power supply circuit that generates an output voltage from an alternating current (AC) voltage inputted thereto. The power supply circuit includes an inductor receiving a rectified voltage corresponding to the AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, and includes a first arithmetic circuit that calculates a first time period, from when the transistor is turned off to when the inductor current reaches a predetermined value, based on a first voltage corresponding to the rectified voltage, a second voltage corresponding to the output voltage, and the inductor current upon turning on of the transistor; and a drive circuit that causes the transistor to be on in a second time period corresponding to the second voltage, and causes the transistor to be off in the first time period.

A switching control circuit for controlling a power supply circuit that generates an output voltage from an alternating current (AC) voltage inputted thereto. The power supply circuit includes an inductor receiving a rectified voltage corresponding to the AC voltage, and a transistor controlling an inductor current flowing through the inductor. The switching control circuit controls switching of the transistor, and includes a first arithmetic circuit that calculates a first time period, from when the transistor is turned off to when the inductor current reaches a predetermined value, based on a first voltage corresponding to the rectified voltage, a second voltage corresponding to the output voltage, and the inductor current upon turning on of the transistor; and a drive circuit that causes the transistor to be on in a second time period corresponding to the second voltage, and causes the transistor to be off in the first time period.

A power conversion circuit for an uninterruptible power system, including an inductor, a first capacitor, a second capacitor, a first switch, a second switch, a third switch, a first diode, a second diode, and a third diode body, is provided. A terminal of the second switch is electrically coupled to the inductor through the first switch, and another terminal of the second switch is electrically coupled to a neutral wire and the third switch. An anode and a cathode of the first diode are electrically coupled to the first switch and a positive DC bus, respectively. A cathode and an anode of the second diode are electrically coupled to the first switch and the third switch, respectively. A cathode and an anode of the third diode are electrically coupled to the third switch and a negative DC bus, respectively. In addition, an uninterruptible power system using the same is provided.

A converter system includes a rectifier, a DC link stage and an inverter connected in series. A control unit includes a slow reference frame angle determination unit that generates a slow reference frame angle θ.sub.r,slow representing an angle that is slowly following a grid phase deviation, and a fast Phase Locked Loop generating a fast reference frame angle θ.sub.r,fast representing an angle that is fast following a grid phase deviation. The control unit uses the slow reference frame angle θ.sub.r,slow and the fast reference frame angle θ.sub.r,fast to control the rectifier output current, and the fast reference frame angle θ.sub.r,fast to control the inverter output voltage and to synchronize the inverter output voltage with the grid voltage.

The present application discloses a flexible excitation system and a method for controlling the same. The flexible excitation system consists of a plurality of groups of flexible excitation power units connected in parallel, a deexcitation circuit unit and a flexible excitation control unit. The method for controlling the flexible excitation system includes: realizing the internal fault-tolerant operation control of the flexible excitation power units by cooperatively controlling AC circuit breakers and DC circuit breakers of the flexible excitation power units and a deexcitation switch; dynamically controlling ceiling voltage when terminal voltage drops by using the fast response control ability of the flexible excitation system, so as to improve the forced excitation output capacity of the self-shunt excitation system. Aiming at the possible overload problem of an excitation transformer during the operation of flexible excitation, an excitation transformer overload limiter for the flexible excitation system is provided to limit the operation state of the excitation transformer within an allowable overload operation range of equipment.

The present application discloses a flexible excitation system and a method for controlling the same. The flexible excitation system consists of a plurality of groups of flexible excitation power units connected in parallel, a deexcitation circuit unit and a flexible excitation control unit. The method for controlling the flexible excitation system includes: realizing the internal fault-tolerant operation control of the flexible excitation power units by cooperatively controlling AC circuit breakers and DC circuit breakers of the flexible excitation power units and a deexcitation switch; dynamically controlling ceiling voltage when terminal voltage drops by using the fast response control ability of the flexible excitation system, so as to improve the forced excitation output capacity of the self-shunt excitation system. Aiming at the possible overload problem of an excitation transformer during the operation of flexible excitation, an excitation transformer overload limiter for the flexible excitation system is provided to limit the operation state of the excitation transformer within an allowable overload operation range of equipment.