Abstract: A power conversion device includes a semiconductor power converter that converts direct current power into alternating current power for a motor, a common-mode reactor having first and second auxiliary windings added thereto, the common-mode reactor reducing common-mode current that may flow between the semiconductor power converter and the motor, a signal generator that superimposes an alternating current on the first auxiliary winding, and a detection circuit that detects a saturation state of the common-mode reactor on the basis of the superimposed current superimposed on the first auxiliary winding and a winding voltage generated in the second auxiliary winding by the superimposed current.

Abstract: A power conversion device includes a semiconductor power converter that converts direct current power into alternating current power for a motor, a common-mode reactor having first and second auxiliary windings added thereto, the common-mode reactor reducing common-mode current that may flow between the semiconductor power converter and the motor, a signal generator that superimposes an alternating current on the first auxiliary winding, and a detection circuit that detects a saturation state of the common-mode reactor on the basis of the superimposed current superimposed on the first auxiliary winding and a winding voltage generated in the second auxiliary winding by the superimposed current.

Abstract: A first control unit outputs a closing-operation command signal to a first switch at a timing calculated based on either a first closing time or a second closing time, whichever is later. The first closing time is a time required for the first switch to transition to a closed state after the first control unit detects a first detection signal indicating that a voltage detected by a voltage detection unit exceeds a predetermined threshold value. The second closing time is a time required for a second switch to transition to a closed state after the first detection signal is detected by a second control unit. The second control unit outputs a closing-operation command signal to the second switch at a timing calculated based on a first time. This can suppress variations in an operating time between a plurality of switches.

Abstract: A first control unit outputs a closing-operation command signal to a first switch at a timing calculated based on either a first closing time or a second closing time, whichever is later. The first closing time is a time required for the first switch to transition to a closed state after the first control unit detects a first detection signal indicating that a voltage detected by a voltage detection unit exceeds a predetermined threshold value. The second closing time is a time required for a second switch to transition to a closed state after the first detection signal is detected by a second control unit. The second control unit outputs a closing-operation command signal to the second switch at a timing calculated based on a first time. This can suppress variations in an operating time between a plurality of switches.

Abstract: A power conversion device includes a main circuit that includes a diode of which cathode is connected to a positive-side power supply path formed between a rectifier circuit and an inverter; and a switching element that is connected between an anode of the diode and a negative-side power supply path formed between the rectifier circuit and the inverter. In the main circuit, a portion between a first terminal and a second terminal, which are provided on the positive-side power supply path, is opened and a reactor is provided between the second terminal and a third terminal, which is provided at a connection point between the diode and the switching element, thus, forming a boost chopper circuit.

Abstract: A power conversion system includes a master power conversion device and one or more slave power conversion devices. Each power conversion device includes: a time counter and a carrier wave generator for synchronization with the time counter. The master power conversion device includes: a synchronization data generating unit for synchronizing a value of the time counter of the slave power conversion device with that of the master power conversion device. The slave power conversion device further includes: a time counter correcting unit that corrects the value of the time counter on the basis of the received synchronization data; a current sensor that detects a current on an output side of the slave power conversion device; and a gate timing adjusting unit that advances or delays a phase of the gate signal of the slave power conversion device.

Abstract: A common mode noise reduction apparatus includes a power converter that supplies electric power to a load; a housing that houses the power converter; a common mode inductor arranged between the power converter and the load; a power wire that passes through the common mode inductor and connects the power converter to the load; a grounding wire that passes through the common mode inductor and connects the housing and a bus of the power converter to ground potential on the load side; a first impedance element provided on the grounding wire between the load and the housing; and a second impedance element provided on the grounding wire between the bus of the power converter and the load.

Abstract: A regenerative converter includes a power conversion unit that includes a plurality of switching elements, an AC terminal connected to an AC side of the power conversion unit, a first terminal connected to one end of the power conversion unit on a DC side, a second terminal connected to the one end of the power conversion unit on the DC side via a backflow prevention element, and a third terminal connected to the other end of the power conversion unit on the DC side.

Abstract: Provided is a semiconductor power conversion apparatus that includes: a semiconductor power converter that performs power conversion by using switching elements and supplies power to a load; a converter-voltage command calculation unit that outputs a voltage command value Vref that controls the semiconductor power converter; a voltage control unit that superimposes a second voltage command value on the voltage command value Vref to generate a voltage command value Vref2; a PWM-signal generation unit that generates a gate signal for controlling driving of the switching elements based on the voltage command value Vref2 and outputs the gate signal; and a bypass unit that is connected to the semiconductor power converter in parallel with the load and branches a current of a frequency of the second voltage command value off from an output current Iout that is output from the semiconductor power converter to the load.

Abstract: A power conversion device includes a main circuit that includes a diode of which cathode is connected to a positive-side power supply path formed between a rectifier circuit and an inverter; and a switching element that is connected between an anode of the diode and a negative-side power supply path formed between the rectifier circuit and the inverter. In the main circuit, a portion between a first terminal and a second terminal, which are provided on the positive-side power supply path, is opened and a reactor is provided between the second terminal and a third terminal, which is provided at a connection point between the diode and the switching element, thus, forming a boost chopper circuit.

Abstract: A power conversion system includes a master power conversion device and one or more slave power conversion devices. Each power conversion device includes: a time counter and a carrier wave generator for synchronization with the time counter. The master power conversion device includes: a synchronization data generating unit for synchronizing a value of the time counter of the slave power conversion device with that of the master power conversion device. The slave power conversion device further includes: a time counter correcting unit that corrects the value of the time counter on the basis of the received synchronization data; a current sensor that detects a current on an output side of the slave power conversion device; and a gate timing adjusting unit that advances or delays a phase of the gate signal of the slave power conversion device.

Abstract: Positive-side DC terminals P1? and P? connected to a positive-side DC bus of a chopper 4 are provided in the chopper 4 and the positive-side DC terminals P1? and P? are connected to positive-side DC terminals P1 and P, respectively. With this configuration, a current of a DC bus of an inverter 2 is drawn via the positive-side DC terminal P1? into the chopper 4 and is returned via the positive-side DC terminal P? to the DC bus of the inverter 2.

Abstract: A common mode noise reduction apparatus includes a power converter that supplies electric power to a load; a housing that houses the power converter; a common mode inductor arranged between the power converter and the load; a power wire that passes through the common mode inductor and connects the power converter to the load; a grounding wire that passes through the common mode inductor and connects the housing and a bus of the power converter to ground potential on the load side; a first impedance element provided on the grounding wire between the load and the housing; and a second impedance element provided on the grounding wire between the bus of the power converter and the load.

Abstract: A noise filter includes a first magnetic core that includes a plurality of leg portions, and a first connection portion and a second connection portion, which connect both ends of the leg portions, a plurality of coils that are wound on the leg portions, respectively, and a second magnetic core that is configured to be attachable to and detachable from the first magnetic core such that a closed magnetic path, which intersects with each of the first connection portion and the second connection portion and which passes through the leg portions, is formed, in which the first magnetic core includes a normal mode inductance, and the closed magnetic path includes a common mode inductance.

Abstract: In the inverter device that receives DC power from the DC common bus and drives a load, the configuration is such that the switching element is arranged on the first current path in which current flows through the positive-side DC terminal during powering, the reverse-connected diode is arranged on the second current path in which current flows through the positive-side DC terminal during regeneration, the charging resistor is arranged on the third current path in which current flows through the positive-side DC terminal when the smoothing capacitor of the smoothing unit is initially charged, and the brake resistor is connected externally between the positive-side DC terminals such that the positive-side DC terminal becomes an end whose potential is the same as that of the positive-side bus of the DC common bus.

Abstract: In the inverter device that receives DC power from the DC common bus and drives a load, the configuration is such that the switching element is arranged on the first current path in which current flows through the positive-side DC terminal during powering, the reverse-connected diode is arranged on the second current path in which current flows through the positive-side DC terminal during regeneration, the charging resistor is arranged on the third current path in which current flows through the positive-side DC terminal when the smoothing capacitor of the smoothing unit is initially charged, and the brake resistor is connected externally between the positive-side DC terminals such that the positive-side DC terminal becomes an end whose potential is the same as that of the positive-side bus of the DC common bus.

Abstract: A noise filter includes a first magnetic core that includes a plurality of leg portions, and a first connection portion and a second connection portion, which connect both ends of the leg portions, a plurality of coils that are wound on the leg portions, respectively, and a second magnetic core that is configured to be attachable to and detachable from the first magnetic core such that a closed magnetic path, which intersects with each of the first connection portion and the second connection portion and which passes through the leg portions, is formed, in which the first magnetic core includes a normal mode inductance, and the closed magnetic path includes a common mode inductance.

Abstract: A power conversion apparatus includes a current sensor that detects a phase current flowing through a phase current line, a first phase-voltage detection unit that detects a first phase voltage in the phase current line with a potential in a P line as a reference, a second phase-voltage detection unit that detects a second phase voltage in the phase current line with a potential in an N line as a reference, an estimation unit that estimates a zero-cross point timing of the phase current based on magnitude and symbol of the first and second phase voltage, a calculation unit that obtains a correction value with respect to a detection value of the current sensor according to the detection value of the current sensor at the estimated zero-cross point timing, and a correction unit that corrects a detection value of the current sensor by using the obtained correction value.

Abstract: Positive-side DC terminals P1? and P? connected to a positive-side DC bus of a chopper 4 are provided in the chopper 4 and the positive-side DC terminals P1? and P? are connected to positive-side DC terminals P1 and P, respectively. With this configuration, a current of a DC bus of an inverter 2 is drawn via the positive-side DC terminal P1? into the chopper 4 and is returned via the positive-side DC terminal P? to the DC bus of the inverter 2.