Abstract: A power conversion system according to the present disclosure includes a first circuit, a second circuit, and a third circuit. The first circuit has a first external terminal thereof electrically connected to either an AC power supply or an AC load. In the power conversion system, a first internal terminal, a second internal terminal, and a third internal terminal are electrically connected to the same connection unit. The second circuit controls a current or power being input to, or output from, the second circuit itself such that the current or the power is synchronized with power ripples caused by the AC power supply or the AC load. Either the AC power supply or the AC load is electrically connected to the first circuit.

Abstract: A power conversion system configured to determine whether or not an abnormality is present in a power conversion circuit, and diagnosis method and program for the power conversion circuit are provided. A power conversion system includes a power conversion circuit, a snubber circuit, and a diagnosis unit. The power conversion circuit includes a transformer and a switching element configured to be electrically connected to the transformer, and the power conversion circuit is configured to convert electric power. The snubber circuit is electrically connected to the transformer and is configured to extract electrical energy from the power conversion circuit. The diagnosis unit is configured to make diagnosis for the power conversion circuit in accordance with at least one of a voltage at a terminal of the transformer, a voltage generated at the snubber circuit, or a current generated at the snubber circuit.

Abstract: A power conversion system according to the present disclosure includes a first circuit, a second circuit, and a third circuit. A first internal terminal, a second internal terminal, and a third internal terminal are electrically connected to the same connection unit. The third circuit provides an output voltage across a secondary winding of a transformer via a switching element and the transformer. The secondary winding is electrically connected to the third internal terminal. The output voltage has a waveform including a rising range in which the output voltage changes from a first potential to a second potential, a falling range in which the output voltage changes from the second potential to the first potential, and a flat range in which the output voltage is maintained at either the first potential or the second potential.

Abstract: A power conversion system includes a converter circuit and a control circuit. The control circuit controls, through use of PWM signals, high potential-side switches for a U-phase circuit, a V-phase circuit, and a W-phase circuit, respectively. The control circuit alternately switches between a first modulation method and a second modulation method at each half carrier period of each of the PWM signals. In the first modulation method, the control circuit determines, as a first value, a duty ratio of the PWM signal for one of a U phase, a V phase, and a W phase that has a maximum phase voltage. In the second modulation method, the control circuit determines, as a second value, the duty ratio of the PWM signal for one of the U phase, the V phase, and the W phase that has a minimum phase voltage.

Abstract: A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.

Abstract: A snubber circuit includes a clamp circuit and a voltage conversion circuit. The clamp circuit is configured to absorb electrical energy of a main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a secondary-side voltage. The main circuit is of insulating type and is configured to perform electric power conversion. The voltage conversion circuit which is of insulating type is electrically connected to a pair of primary-side voltage points on a primary side of the main circuit and is configured to subject, to direct-current conversion, the direct-current voltage generated by the clamp circuit and output the direct-current voltage to the pair of primary-side voltage points. The voltage conversion circuit includes a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer.

Abstract: The control unit controls the converter unit not to cause transfer of power between the transformer circuit unit and the converter unit in the first time period including the reversal time period in which a reversal of polarity of the voltage across the primary winding occurs. The control unit controls the converter unit to cause transfer of power in the first direction from the transformer circuit unit to the converter unit or the second direction opposite to the first direction in the second time period different from the first time period.

Abstract: A power conversion system includes a first capacitor, an isolated type converter circuit, and a control circuit. The first capacitor is connected to the direct-current power supply via an inrush current prevention circuit. The inrush current prevention circuit is switchable at least between a high-impedance state and a low-impedance state. The converter circuit includes a transformer, and the first capacitor is connected to a primary winding wire of the transformer. The control circuit controls the inrush current prevention circuit and the converter circuit to cause the converter circuit to start operating, and then, the control circuit switches the inrush current prevention circuit from the high-impedance state to the low-impedance state.

Abstract: A snubber circuit includes a clamp circuit and a voltage conversion circuit. The clamp circuit is configured to absorb electrical energy of a main circuit from a pair of secondary-side voltage points on a secondary side of the main circuit to clamp a secondary-side voltage. The main circuit is of insulating type and is configured to perform electric power conversion. The voltage conversion circuit which is of insulating type is electrically connected to a pair of primary-side voltage points on a primary side of the main circuit and is configured to subject, to direct-current conversion, the direct-current voltage generated by the clamp circuit and output the direct-current voltage to the pair of primary-side voltage points. The voltage conversion circuit includes a transformer, a first capacitance component electrically connected to a primary winding wire of the transformer, and a second capacitance component electrically connected to a secondary winding wire of the transformer.

Abstract: When a magnitude of a voltage between a pair of first voltage points in a main circuit exceeds a first clamp value, a first clamp circuit absorbs electrical energy of the main circuit from the pair of first voltage points to clamp the voltage to the first clamp value. When a magnitude of a voltage between a pair of second voltage points in the main circuit falls below a second clamp value, a second clamp circuit injects electrical energy to the main circuit from the pair of second voltage points to clamp the voltage to the second clamp value. A voltage conversion circuit performs voltage conversion between a first clamp voltage defining a first clamp value and a second clamp voltage defining a second clamp value.

Abstract: A power conversion system includes a converter circuit and a control circuit. The control circuit controls, through use of PWM signals, high potential-side switches for a U-phase circuit, a V-phase circuit, and a W-phase circuit, respectively. The control circuit alternately switches between a first modulation method and a second modulation method at each half carrier period of each of the PWM signals. In the first modulation method, the control circuit determines, as a first value, a duty ratio of the PWM signal for one of a U phase, a V phase, and a W phase that has a maximum phase voltage. In the second modulation method, the control circuit determines, as a second value, the duty ratio of the PWM signal for one of the U phase, the V phase, and the W phase that has a minimum phase voltage.

Abstract: A power conversion system includes a first capacitor, an isolated type converter circuit, and a control circuit. The first capacitor is connected to the direct-current power supply via an inrush current prevention circuit. The inrush current prevention circuit is switchable at least between a high-impedance state and a low-impedance state. The converter circuit includes a transformer, and the first capacitor is connected to a primary winding wire of the transformer. The control circuit controls the inrush current prevention circuit and the converter circuit to cause the converter circuit to start operating, and then, the control circuit switches the inrush current prevention circuit from the high-impedance state to the low-impedance state.

Abstract: The control unit controls the converter unit not to cause transfer of power between the transformer circuit unit and the converter unit in the first time period including the reversal time period in which a reversal of polarity of the voltage across the primary winding occurs. The control unit controls the converter unit to cause transfer of power in the first direction from the transformer circuit unit to the converter unit or the second direction opposite to the first direction in the second time period different from the first time period.

Abstract: When a magnitude of a voltage between a pair of first voltage points in a main circuit exceeds a first clamp value, a first clamp circuit absorbs electrical energy of the main circuit from the pair of first voltage points to clamp the voltage to the first clamp value. When a magnitude of a voltage between a pair of second voltage points in the main circuit falls below a second clamp value, a second clamp circuit injects electrical energy to the main circuit from the pair of second voltage points to clamp the voltage to the second clamp value. A voltage conversion circuit performs voltage conversion between a first clamp voltage defining a first clamp value and a second clamp voltage defining a second clamp value.

Abstract: A control unit controls an inverter circuit such that a positive voltage and a negative voltage are alternately applied to a primary winding. The control unit controls a cycloconverter so as to allow no power to be transmitted between the cycloconverter and the inverter circuit in a first period including an inversion period during which a voltage of the primary winding has its polarity inverted. The control unit also controls the cycloconverter so as to allow power to be transmitted either in a first direction from the cycloconverter toward the inverter circuit, or in a second direction opposite from the first direction, in a second period different from the first period.

Abstract: A power converter includes first to fourth terminals, a transformer including primary and secondary windings, an inverter connected between the first and second terminals and the primary winding, a converter connected between fifth and sixth terminals, and a controller. The converter includes first to eighth switch circuits each including a diode and a switch connected in parallel. When a voltage between the fifth and sixth terminals has first polarity, the controller controls the first switch circuit to be in on-state during a first on-period and controls the fifth switch circuit to be in on-state during a second on-period completely including the first on-period. When the voltage between the fifth and sixth terminals has second polarity, the controller controls the second switch circuit to be in on-state during a third on-period and controls the sixth switch circuit to be in on-state during a fourth on-period completely including the third on-period.

Abstract: A power conversion device includes first and second terminals connected to a DC power source, third and fourth terminals connected to a commercial power system or a load, a transformer including a primary winding having seventh and eighth terminals and a secondary winding having fifth and sixth terminals, an inverter circuit connected between the first and second terminals and the seventh and eighth terminals, a converter circuit connected between the fifth and sixth terminals and the third and fourth terminals, a diode bridge including first and second AC input terminals connected to the fifth and sixth terminals, respectively, and first and second DC output terminals, a first capacitor connected between the first and second DC output terminals, and a first resistor connected in parallel with the first capacitor between the first and second DC output terminals.

Abstract: A power conversion device includes first and second terminals connected to a DC power source, third and fourth terminals connected to a commercial power system or a load, a transformer including a primary winding having seventh and eighth terminals and a secondary winding having fifth and sixth terminals, an inverter circuit connected between the first and second terminals and the seventh and eighth terminals, a converter circuit connected between the fifth and sixth terminals and the third and fourth terminals, a diode bridge including first and second AC input terminals connected to the fifth and sixth terminals, respectively, and first and second DC output terminals, a first capacitor connected between the first and second DC output terminals, and a first resistor connected in parallel with the first capacitor between the first and second DC output terminals.

Abstract: A power converter includes first to fourth terminals, a transformer including primary and secondary windings, an inverter connected between the first and second terminals and the primary winding, a converter connected between fifth and sixth terminals, and a controller. The converter includes first to eighth switch circuits each including a diode and a switch connected in parallel. When a voltage between the fifth and sixth terminals has first polarity, the controller controls the first switch circuit to be in on-state during a first on-period and controls the fifth switch circuit to be in on-state during a second on-period completely including the first on-period. When the voltage between the fifth and sixth terminals has second polarity, the controller controls the second switch circuit to be in on-state during a third on-period and controls the sixth switch circuit to be in on-state during a fourth on-period completely including the third on-period.

Abstract: A driving apparatus of the present disclosure includes a coil including a second terminal connected to a control terminal of a switching element, a charging switch connected between a first potential line and a first terminal of the coil, a clamp switch connected between the first potential line and the control terminal of the switching element, a charging diode connected between a second potential line and the first terminal of the coil, and a control circuit that outputs a charging control signal for turning on the charging switch and for turning off the charging switch before a potential of the control terminal of the switching element reaches the first potential and a clamp control signal for turning on the clamp switch after the charging switch is turned on.