Abstract: When a secondary battery is charged, a switch is closed, and a first boost chopper circuit, a second boost chopper circuit, and a totem-pole bridgeless power factor correction circuit, which are coupled in parallel to each other, are driven to operate in an interleaving manner, and in this state, an alternating-current voltage inputted from an AC input terminal is converted into a direct current, and the direct current is outputted from a direct current output terminal. When alternating current is outputted using an AC output terminal, the switch is closed, and the totem-pole bridgeless PFC circuit is used, and in this state, a DC voltage from the secondary battery is converted into an alternating current, and the alternating current is outputted from the AC output terminal.

Abstract: A power supply circuit includes a transformer having a primary winding and secondary windings, a first power conversion circuit configured to convert a DC voltage into an AC voltage and output the AC voltage to the primary winding, a rectifying and smoothing circuit that is connected to the secondary winding and is configured to rectify and smooth an alternating current output from the secondary winding, and a second power conversion circuit configured to boost a direct current output from the rectifying and smoothing circuit and supply to a load a DC voltage lower than a rated voltage of the load set in advance.

Abstract: Provided is an uninterruptible power supply system. The uninterruptible power supply system includes a power supply unit including a power supply circuit converting alternating current power into direct current voltage to be supplied to a load apparatus. The uninterruptible power supply system includes a battery unit including a battery circuit. The battery circuit stores direct current power and discharges the direct current power to generate direct current voltage to be supplied to the load apparatus. The uninterruptible power supply system includes a rack in which each of the power supply unit and the battery unit is mounted.

Abstract: An uninterruptible power supply apparatus includes a power supply unit converting AC power to generate a DC voltage to be supplied to a loading device. The uninterruptible power supply apparatus further includes a first battery unit connected to the power supply unit to receive a DC current therefrom, and stores first DC power generated from the DC voltage. The first battery unit generates a DC voltage to be supplied to the loading device from the first DC power. The uninterruptible power supply apparatus includes a second battery unit connected in parallel to the power supply unit and stores second DC power, and generates, from the second DC power stored in the second battery unit, a DC voltage to be supplied to the loading device. The uninterruptible power supply apparatus further includes a controller for controlling operation of the power supply unit, the first battery unit and the second battery unit.

Abstract: A motor drive system wherein an LC circuit exists between an inverter and a motor is such that switching of semiconductor switching elements Su to Sw and Sx to Sz configuring the inverter is controlled by an on-signal formed of a first on-signal, a second on-signal, and an off-state period of a time the same as the first on-signal provided between the first on-signal and second on-signal, and by an off-signal formed of a first off-signal, a second off-signal, and an on-state period of a time the same as the first off-signal provided between the first off-signal and second off-signal, and surge voltage applied to an input terminal of the motor is suppressed by the time of the first on-signal and the time of the second off-signal being set to one-sixth of a resonance cycle specific to the LC circuit.

Abstract: An uninterruptible power supply apparatus includes a power supply unit converting AC power to generate a DC voltage to be supplied to a loading device. The uninterruptible power supply apparatus further includes a first battery unit connected to the power supply unit to receive a DC current therefrom, and stores first DC power generated from the DC voltage. The first battery unit generates a DC voltage to be supplied to the loading device from the first DC power. The uninterruptible power supply apparatus includes a second battery unit connected in parallel to the power supply unit and stores second DC power, and generates, from the second DC power stored in the second battery unit, a DC voltage to be supplied to the loading device. The uninterruptible power supply apparatus further includes a controller for controlling operation of the power supply unit, the first battery unit and the second battery unit.

Abstract: Provided is an uninterruptible power supply system. The uninterruptible power supply system includes a power supply unit including a power supply circuit converting alternating current power into direct current voltage to be supplied to a load apparatus. The uninterruptible power supply system includes a battery unit including a battery circuit. The battery circuit stores direct current power and discharges the direct current power to generate direct current voltage to be supplied to the load apparatus. The uninterruptible power supply system includes a rack in which each of the power supply unit and the battery unit is mounted.

Abstract: A miniaturized direct-current switch with which power loss is reduced when establishing continuity of a direct-current path is provided. The direct-current switch includes an electronic open/close switch inserted in a direct-current path along which a direct current flows in order to make the direct-current path an open circuit or a closed circuit, a parallel mechanical open/close switch connected in parallel to the electronic open/close switch, and a switch control circuit that controls the opening or closing time difference mutually between the parallel mechanical open/close switch and the electronic open/close switch, wherein the switch control circuit makes the parallel mechanical open/close switch a closed circuit a predetermined time after the electronic open/close switch has been made a closed circuit.

Abstract: A power supply device that is able to switch between rectifier circuits in accordance with the voltage of a multi-phase AC power supply, and able to accommodate different power supply voltages. The power supply device has rectifier circuits that include a first circuit that rectifies a line voltage of the AC power supply, converting it into a direct current voltage of a first predetermined value, when the voltage of the AC power supply is a predetermined value or less, and a second circuit that rectifies a phase voltage of the AC power supply, converting it into a direct current voltage of a second predetermined value, when the voltage of the alternating current power supply exceeds the predetermined value. The first and second circuits operate in such a way that the AC input current is of the same phase as the voltage of the AC power supply.

Abstract: Aspects of the invention provide a method for starting up a DC-DC converter by which an output voltage can be prevented from overshooting and body diodes of switching devices can be prevented from reverse recovery. In the start-up method, the phases of gate signals of third and fourth switching devices are gradually shifted relative to the phases of gate signals of first and second switching devices. With increase of the phase shift, a voltage on a primary side of a transformer is also increased, and an output voltage is also increased.

Abstract: A motor drive system wherein an LC circuit exists between an inverter and a motor is such that switching of semiconductor switching elements Su to Sw and Sx to Sz configuring the inverter is controlled by an on-signal formed of a first on-signal, a second on-signal, and an off-state period of a time the same as the first on-signal provided between the first on-signal and second on-signal, and by an off-signal formed of a first off-signal, a second off-signal, and an on-state period of a time the same as the first off-signal provided between the first off-signal and second off-signal, and surge voltage applied to an input terminal of the motor is suppressed by the time of the first on-signal and the time of the second off-signal being set to one-sixth of a resonance cycle specific to the LC circuit.

Abstract: A high power factor rectifier circuit, provided with switching sections connected to an AC power supply for converting an AC voltage to a DC voltage, is formed with a bypass circuit provided. The bypass circuit, when the voltage of the AC power supply becomes higher than the voltage across a smoothing capacitor provided on the DC output side, makes a charge current flowing from the AC power supply to the capacitor bypass the switching section by making the switching section out of conduction. Thus, a rectifier circuit is provided which can be safely operated without causing any damage, or with minimized damage, even though an inrush current flows at turning-on the power or at recovery from a power interruption.

Abstract: Two conducting wires are used in one embodiment of an inductor. Opposite ends of each of the conducting wires are connected to leader lines (terminals) shared by the conducting wires. Each of the conducting wires is wound to make half a round of an annular or ring-like magnetic substance. One of the conducting wires is wound around a lower half area of the magnetic substance to form one winding while the other conducting wire is wound around an upper half area of the magnetic substance to form another winding. In this manner, the distance between the leader lines can be increased to eliminate parasitic capacitance between the leader lines. The magnetic fluxes generated by current flowing in the two windings are in the same direction. Thus, it is possible to provide an inductor whose total parasitic capacitance is reduced. In other embodiments, additional conducting wires are used.

Abstract: A power supply device that is able to switch between rectifier circuits in accordance with the voltage of a multi-phase AC power supply, and able to accommodate different power supply voltages. The power supply device has rectifier circuits that include a first circuit that rectifies a line voltage of the AC power supply, converting it into a direct current voltage of a first predetermined value, when the voltage of the AC power supply is a predetermined value or less, and a second circuit that rectifies a phase voltage of the AC power supply, converting it into a direct current voltage of a second predetermined value, when the voltage of the alternating current power supply exceeds the predetermined value. The first and second circuits operate in such a way that the AC input current is of the same phase as the voltage of the AC power supply.

Abstract: An entirely integrated EMI filter is based on a flexible multi-layer strip material. An EE or EI core comprises two side pillars and one middle pillar and forms a closed magnetic circuit. The middle pillar has an air gap. A first winding and a second winding respectively are wound around the two side pillars in a same winding direction. The middle pillar is wound with a third winding and a fourth winding, or with only a fifth winding. Passive components (e.g., all passive components) of the EMI filter are integrated into one core so that in its differential mode, insertion loss is significantly reduced, the size and volume are reduced, and the distribution constant of the EMI filter has less impact on the filter's performance.

Abstract: A miniaturized direct-current switch with which power loss is reduced when establishing continuity of a direct-current path is provided. The direct-current switch includes an electronic open/close switch inserted in a direct-current path along which a direct current flows in order to make the direct-current path an open circuit or a closed circuit, a parallel mechanical open/close switch connected in parallel to the electronic open/close switch, and a switch control circuit that controls the opening or closing time difference mutually between the parallel mechanical open/close switch and the electronic open/close switch, wherein the switch control circuit makes the parallel mechanical open/close switch a closed circuit a predetermined time after the electronic open/close switch has been made a closed circuit.

Abstract: Two conducting wires are used in one embodiment of an inductor. Opposite ends of each of the conducting wires are connected to leader lines (terminals) shared by the conducting wires. Each of the conducting wires is wound to make half a round of an annular or ring-like magnetic substance. One of the conducting wires is wound around a lower half area of the magnetic substance to form one winding while the other conducting wire is wound around an upper half area of the magnetic substance to form another winding. In this manner, the distance between the leader lines can be increased to eliminate parasitic capacitance between the leader lines. The magnetic fluxes generated by current flowing in the two windings are in the same direction. Thus, it is possible to provide an inductor whose total parasitic capacitance is reduced. In other embodiments, additional conducting wires are used.

Abstract: An integrated structure of common-mode inductors and differential-mode capacitors in an EMI filter realized using a flexible circuit board, including: a closed magnetic circuit formed by a first magnetic core and a second magnetic core, optionally including an air gap formed in a middle pillar of the magnetic cores, and with a flexible printed circuit board (FPC) wound on at least one pillar, the FPC formed by laminating alternating insulating and copper foil layers. The integrated structure of inductors and capacitors is advantageous in reducing the volume of the EMI filter and improving the power density of an electronic power transformer.

Abstract: Aspects of the invention provide a method for starting up a DC-DC converter by which an output voltage can be prevented from overshooting and body diodes of switching devices can be prevented from reverse recovery. In the start-up method, the phases of gate signals of third and fourth switching devices are gradually shifted relative to the phases of gate signals of first and second switching devices. With increase of the phase shift, a voltage on a primary side of a transformer is also increased, and an output voltage is also increased.

Abstract: A high power factor rectifier circuit, provided with switching sections connected to an AC power supply for converting an AC voltage to a DC voltage, is formed with a bypass circuit provided. The bypass circuit, when the voltage of the AC power supply becomes higher than the voltage across a smoothing capacitor provided on the DC output side, makes a charge current flowing from the AC power supply to the capacitor bypass the switching section by making the switching section out of conduction. Thus, a rectifier circuit is provided which can be safely operated without causing any damage, or with minimized damage, even though an inrush current flows at turning-on the power or at recovery from a power interruption.