Abstract: A period from when switching elements S1, S4 at first diagonal positions in a full-bridge inverter are turned off at the same time to when switching elements S2, S3 at second diagonal positions are turned on at the same time, is defined as T1, and a period from when the switching elements S2, S3 at the second diagonal positions are turned off at the same time to when the switching elements S1, S4 at the first diagonal positions are turned on at the same time, is defined as T2. With a total length of T1 and T2 set to be constant, the lengths of T1 and T2 are controlled to be changed every switching cycle.

Abstract: An output terminal of a contact type charger connected to an AC power supply 1 and being for boosting or stepping down an input voltage, and an output terminal of a non-contact type charger for receiving power in a non-contact manner are connected to an input terminal of a DC/DC converter via an integrated bus, a DC link capacitor is connected between an AC/DC converter and an isolated DC/DC converter included in the contact type charger, an integrated capacitor is connected to the integrated bus, and a control circuit adjusts a DC voltage of the DC link capacitor or the integrated capacitor such that at least one of power losses or a total power loss of the contact type charger, the non-contact type charger, and the DC/DC converter is reduced.

Abstract: A power conversion device includes: a main body including a substrate to which a power conversion unit and a coil are provided; and a first heat dissipation portion which holds the substrate and dissipates heat of the substrate, wherein the substrate is formed by one sheet, the coil is formed integrally with the substrate, the first heat dissipation portion is fixed to a substrate first surface of the substrate, a heat dissipation second surface of the first heat dissipation portion has a coil cooling portion opposed to and abutting on a part where the coil is formed, of the substrate.

Abstract: A magnetically coupled reactor and a DC/DC converter are provided between a DC power supply and an inverter. A first smoothing capacitor is provided between the DC power supply and the coupled reactor. A second smoothing capacitor is provided between the DC/DC converter and the inverter. A controller is provided in order to control switching operations of the inverter and the DC/DC converter. The controller causes semiconductor switching elements composing upper and lower arms of the DC/DC converter to perform complementary operations so as to be alternately turned on/off, and causes left and right legs to operate with their switching phases shifted from each other, thereby electric charges stored in both smoothing capacitors are discharged by energy loss in the coupled reactor and the DC/DC converter.

Abstract: A DC capacitor and a leg are connected in parallel to a high-voltage-side power line and a low-voltage-side power line. The leg includes a plurality of semiconductor switching elements connected in series between the power lines with an output end, connected to a load, between the plurality of semiconductor switching elements. An attenuator for attenuating a resonance is connected to a main circuit loop formed of the DC capacitor, the high-voltage-side power line, the low-voltage-side power line, a semiconductor switching element in ON state, and a drain-source parasitic capacitance of a semiconductor switching element in OFF state.

Abstract: An output terminal of a contact type charger connected to an AC power supply 1 and being for boosting or stepping down an input voltage, and an output terminal of a non-contact type charger for receiving power in a non-contact manner are connected to an input terminal of a DC/DC converter via an integrated bus, a DC link capacitor is connected between an AC/DC converter and an isolated DC/DC converter included in the contact type charger, an integrated capacitor is connected to the integrated bus, and a control circuit adjusts a DC voltage of the DC link capacitor or the integrated capacitor such that at least one of power losses or a total power loss of the contact type charger, the non-contact type charger, and the DC/DC converter is reduced.

Abstract: A control circuit performs at least pulse width modulation control on a first leg and selects to perform pulse width modulation control and pulse frequency modulation control, to perform pulse width modulation control and phase shift modulation control, or to perform pulse width modulation control, pulse frequency modulation control, and phase shift modulation control on a second leg, based on comparison of a voltage conversion ratio between DC voltage of a DC capacitor and output voltage to a load with at least one threshold.

Abstract: A DC capacitor and a leg are connected in parallel to a high-voltage-side power line and a low-voltage-side power line. The leg includes a plurality of semiconductor switching elements connected in series between the power lines with an output end, connected to a load, between the plurality of semiconductor switching elements. An attenuator for attenuating a resonance is connected to a main circuit loop formed of the DC capacitor, the high-voltage-side power line, the low-voltage-side power line, a semiconductor switching element in ON state, and a drain-source parasitic capacitance of a semiconductor switching element in OFF state.

Abstract: A magnetically coupled reactor and a DC/DC converter are provided between a DC power supply and an inverter. A first smoothing capacitor is provided between the DC power supply and the coupled reactor. A second smoothing capacitor is provided between the DC/DC converter and the inverter. A controller is provided in order to control switching operations of the inverter and the DC/DC converter. The controller causes semiconductor switching elements composing upper and lower arms of the DC/DC converter to perform complementary operations so as to be alternately turned on/off, and causes left and right legs to operate with their switching phases shifted from each other, thereby electric charges stored in both smoothing capacitors are discharged by energy loss in the coupled reactor and the DC/DC converter.

Abstract: A control circuit performs at least pulse width modulation control on a first leg and selects to perform pulse width modulation control and pulse frequency modulation control, to perform pulse width modulation control and phase shift modulation control, or to perform pulse width modulation control, pulse frequency modulation control, and phase shift modulation control on a second leg based on comparison of a voltage conversion ratio between DC voltage of a DC capacitor and output voltage to a load with at least one threshold.

Abstract: A power conversion device includes: a main body including a substrate to which a power conversion unit and a coil are provided; and a first heat dissipation portion which holds the substrate and dissipates heat of the substrate, wherein the substrate is formed by one sheet, the coil is formed integrally with the substrate, the first heat dissipation portion is fixed to a substrate first surface of the substrate, a heat dissipation second surface of the first heat dissipation portion has a coil cooling portion opposed to and abutting on a part where the coil is formed, of the substrate.

Abstract: A period from when switching elements S1, S4 at first diagonal positions in a full-bridge inverter are turned off at the same time to when switching elements S2, S3 at second diagonal positions are turned on at the same time, is defined as T1, and a period from when the switching elements S2, S3 at the second diagonal positions are turned off at the same time to when the switching elements S1, S4 at the first diagonal positions are turned on at the same time, is defined as T2. With a total length of T1 and T2 set to be constant, the lengths of T1 and T2 are controlled to be changed every switching cycle.

Abstract: A power conversion device includes an input detector for detecting input parameters of the DC input to the inverter; an output detector for detecting output parameters of the DC output from the power converter device; a duty calculator for calculating a duty for the switching elements of the inverter; a frequency search range calculator for determining an upper limit and a lower limit of a frequency search range for determining the drive frequency after the operating condition is changed, using at least one parameter of the input parameters, the output parameters, and a duty parameter; and a frequency search processor for determining the drive frequency by searching the frequency search range.

Abstract: A power conversion device includes a first switching unit connected between a DC power supply and an inverter circuit, a resonant circuit connected to the input of the inverter circuit and formed by connecting a capacitor, a reactor, and a second switching unit, and a control unit, wherein, during a resonant operation period in which the first switching unit is controlled to be off and the second switching unit is controlled to be on, the control unit controls the inverter circuit to shift from a mode in which current flows back through one of upper and lower arms of the inverter circuit to a mode in which current flows back through the other arm, and provides a period in which the upper and lower arms for every phase of the inverter circuit are turned on simultaneously.

Abstract: A power conversion device includes a first switching unit connected between a DC power supply and an inverter circuit, a resonant circuit connected to the input of the inverter circuit and formed by connecting a capacitor, a reactor, and a second switching unit, and a control unit, wherein, during a resonant operation period in which the first switching unit is controlled to be off and the second switching unit is controlled to be on, the control unit controls the inverter circuit to shift from a mode in which current flows back through one of upper and lower arms of the inverter circuit to a mode in which current flows back through the other arm, and provides a period in which the upper and lower arms for every phase of the inverter circuit are turned on simultaneously.

Abstract: A full-bridge inverter is configured with a parallel connection of a first leg and a second leg, and controlled in a dual-leg resonant mode in which a positive-side switching element of the first leg and a negative-side switching element of the second leg are turned on/off at the same time and a negative-side switching element of the first leg and a positive-side switching element of the second leg are turned on/off at the same time, and controlled in a single-leg resonant mode in which the positive-side switching element of the first leg and the negative-side switching element of the second leg, and the negative-side switching element of the first leg and the positive-side switching element of the second leg are turned on/off shiftedly in time by a phase shift amount.

Abstract: A diode rectifier rectifies an AC voltage output from a neutral-grounding three-phase AC power supply to a DC voltage. A smoothing capacitor smoothes the DC voltage rectified by the diode rectifier. An inverter converts the DC voltage smoothed by the smoothing capacitor into a desired AC voltage. A bidirectional switch and a Y capacitor are connected in series between one end of the smoothing capacitor and the ground. A detector detects a voltage across both ends of the smoothing capacitor. A controller drives the bidirectional switch in response to an output of the detector.

Abstract: An electric motor drive device includes a smoothing capacitor and an inverter, and further includes an overvoltage protection unit for overvoltage protection for the smoothing capacitor, and a phase short-circuit control unit. The overvoltage protection unit includes: a discharge circuit having a discharge resistor and an IGBT connected in series; and a first determination circuit which determines, with determination delay, that smoothing capacitor voltage exceeds first set voltage, and turns on the IGBT. The phase short-circuit control unit is provided in a control device for drive-controlling the inverter and includes a second determination circuit which determines, with a determination period longer than the determination delay of the first determination circuit, that smoothing capacitor voltage exceeds second set voltage lower than the first set voltage, to perform phase short-circuit control for the inverter.

Abstract: A power conversion device includes an input detector for detecting input parameters of the DC input to the inverter; an output detector for detecting output parameters of the DC output from the power converter device; a duty calculator for calculating a duty for the switching elements of the inverter; a frequency search range calculator for determining an upper limit and a lower limit of a frequency search range for determining the drive frequency after the operating condition is changed, using at least one parameter of the input parameters, the output parameters, and a duty parameter; and a frequency search processor for determining the drive frequency by searching the frequency search range.

Abstract: An air-conditioning apparatus includes: a plurality of compressors included in one or more refrigerant circuits which air-condition a target space to be air-conditioned; a power converter which converts electric power supplied from a power source unit and supply the compressors with electric power for driving the compressors at an arbitrary drive rotation speed; a switching device which perform switching between a power supplying operation to cause each of the compressors to be supplied with electric power from the power converter and a power supplying operation to cause each of the compressors to be supplied with electric power directly from the power source unit; and a controller which controls the power converter and the switching device.