Abstract: A motor drive device receiving AC power supplied from an AC source and driving a motor includes: a converter circuit converting the AC power into DC power; an inverter circuit converting the DC power into AC power to drive the motor; and a current detector detecting input current flowing on the AC side of the converter circuit. The motor drive device also includes a converter device and an inverter device. The converter device includes a control unit performing control such that input current or input power supplied to the converter circuit does not exceed an upper limit, based on a value detected by the current detector. The inverter device includes a control unit detecting voltage of a DC bus connecting the converter circuit and the inverter circuit, and limiting the output power of the inverter circuit when a detection value of the bus voltage decreases to a set lower limit.

Abstract: An insulation detector for highly accurately detecting or measuring, with a simple configuration, insulation resistance of a load or an apparatus to a ground or a housing and connected to an electric apparatus including one or both of an intra-apparatus capacitor and a battery, the insulation detector including an intra-insulation detector capacitor, a voltage detecting unit that detects a voltage of the intra-insulation detector capacitor, and a current-path forming switch for connecting the ground or the housing, the intra-apparatus capacitor, and the intra-insulation detector capacitor in series and forming a current path including insulation resistance of the electric apparatus. The insulation detector measures the insulation resistance by measuring a time constant of a change in the voltage of the intra-insulation detector capacitor.

Abstract: A motor drive device receiving AC power supplied from an AC source and driving a motor includes: a converter circuit converting the AC power into DC power; an inverter circuit converting the DC power into AC power to drive the motor; and a current detector detecting input current flowing on the AC side of the converter circuit. The motor drive device also includes a converter device and an inverter device. The converter device includes a control unit performing control such that input current or input power supplied to the converter circuit does not exceed an upper limit, based on a value detected by the current detector. The inverter device includes a control unit detecting voltage of a DC bus connecting the converter circuit and the inverter circuit, and limiting the output power of the inverter circuit when a detection value of the bus voltage decreases to a set lower limit.

Abstract: A motor drive device provided to a control panel to drive a plurality of motors includes a plate-shaped fin base that includes a first plate surface and a second plate surface, and a plate-shaped heat radiator that is thermally connected to the first plate surface and is provided with a first normal to its plate surface intersecting a second normal to the first plate surface. The motor drive device also includes a semiconductor device that drives a first motor and is thermally connected to the heat radiator, a semiconductor device that drives a second motor and is thermally connected to the first plate surface, and fins that are thermally connected to the second plate surface opposite from the first plate surface of the fin base and are provided in an air passage formed in the control panel.

Abstract: A motor drive device provided to a control panel to drive a plurality of motors includes a plate-shaped fin base that includes a first plate surface and a second plate surface, and a plate-shaped heat radiator that is thermally connected to the first plate surface and is provided with a first normal to its plate surface intersecting a second normal to the first plate surface. The motor drive device also includes a semiconductor device that drives a first motor and is thermally connected to the heat radiator, a semiconductor device that drives a second motor and is thermally connected to the first plate surface, and fins that are thermally connected to the second plate surface opposite from the first plate surface of the fin base and are provided in an air passage formed in the control panel.

Abstract: A power regenerative converter, includes: a power module configured to include rectifiers and regenerative switches; a smoothing capacitor connected to direct-current power supply terminals, and that accumulates direct-current power during an alternating-current to direct-current conversion; a bus current detector that detects a bus current flowing between either of the direct-current power supply terminals and the smoothing capacitor; a power supply phase detector that detects a phase of an input power supply; a base drive signal generator that generates base drive signals that perform ON/OFF control of the regenerative switching elements based on a power supply phase detected by the power supply phase detection unit; a regeneration controller that performs a start and stop process of a power regenerative operation based on a detection result of the bus current detector and the base drive signals; and an overload detector that detects overload of a power regenerative converter based on the detection result o

Abstract: An insulation detector for highly accurately detecting or measuring, with a simple configuration, insulation resistance of a load or an apparatus to a ground or a housing and connected to an electric apparatus including one or both of an intra-apparatus capacitor and a battery, the insulation detector including an intra-insulation detector capacitor, a voltage detecting unit that detects a voltage of the intra-insulation detector capacitor, and a current-path forming switch for connecting the ground or the housing, the intra-apparatus capacitor, and the intra-insulation detector capacitor in series and forming a current path including insulation resistance of the electric apparatus. The insulation detector measures the insulation resistance by measuring a time constant of a change in the voltage of the intra-insulation detector capacitor.

Abstract: An insulation detector for highly accurately detecting or measuring, with a simple configuration, insulation resistance of a load or an apparatus to a ground or a housing and connected to an electric apparatus including one or both of an intra-apparatus capacitor and a battery, the insulation detector including an intra-insulation detector capacitor, a voltage detecting unit that detects a voltage of the intra-insulation detector capacitor, and a current-path forming switch for connecting the ground or the housing, the intra-apparatus capacitor, and the intra-insulation detector capacitor in series and forming a current path including insulation resistance of the electric apparatus. The insulation detector measures the insulation resistance by measuring a time constant of a change in the voltage of the intra-insulation detector capacitor.

Abstract: A power regenerative converter, includes: a power module configured to include rectifiers and regenerative switches; a smoothing capacitor connected to direct-current power supply terminals, and that accumulates direct-current power during an alternating-current to direct-current conversion; a bus current detector that detects a bus current flowing between either of the direct-current power supply terminals and the smoothing capacitor; a power supply phase detector that detects a phase of an input power supply; a base drive signal generator that generates base drive signals that perform ON/OFF control of the regenerative switching elements based on a power supply phase detected by the power supply phase detection unit; a regeneration controller that performs a start and stop process of a power regenerative operation based on a detection result of the bus current detector and the base drive signals; and an overload detector that detects overload of a power regenerative converter based on the detection result o

Abstract: A drive circuit for a switching element according to the present embodiment includes a drive-voltage generation circuit that generates a driving voltage for a switching element; and a filter circuit that filters the driving voltage. The filter circuit forms a circuit having a step response represented by a second-order transfer function together with an internal gate resistor and an input capacitor between a gate terminal and an emitter terminal of the switching element. The circuit has a circuit constant that is set to make an attenuation coefficient of the transfer function be a value within a certain range.

Abstract: A switching power supply circuit includes a switching element connected to a primary winding wire of a transformer in series, capacitors connected to secondary winding wires of the transformer via diodes, and an IC for power supply control that controls ON/OFF operation of the switching element on the basis of a charged voltage of the capacitors. Commanded voltages are charged in the capacitors after electric power is supplied to a main power supply, and further, after the elapse of a delay time set in advance, a control circuit, which controls the entire apparatus, controls a main circuit and a peripheral apparatus circuit to start operations.

Abstract: A drive circuit for a power semiconductor element includes: a voltage-command generation unit that generates a voltage command VGEref, which is a charge command between the gate and emitter terminals of a power semiconductor element; and a subtracter that calculates a deviation voltage Verr between the voltage command VGEref and the voltage between the gate and emitter terminals. The drive circuit also includes: a gate current controller that is input with the deviation voltage Verr and calculates a gate-current command voltage VIGref for determining the gate current that is caused to flow to the gate terminal of the power semiconductor element; a gate-current command limiter that limits the gate-current command voltage VIGref; and a gate-current supply device that is input with an actual gate-current command voltage VIGout and that supplies a gate current to the gate terminal of the power semiconductor element.

Abstract: A CR snubber circuit capable of increasing a reduction effect of the effective inductance component and suppressing a ringing component generated at the time of switching the switching element is obtained. A first current path formed on one surface of the substrate and a second current path formed on the other surface, which is the opposite side of the one surface of the substrate, are opposed to each other with the substrate being sandwiched therebetween, and the capacitor 5 and the resistor 6 are arranged such that current flows in opposite directions in the first current path and the second current path, and a band elimination filter is formed by the capacitor 5, the resistor 6, and an effective inductance component obtained by coupling an inductance component included in the first current path and an inductance component included in the second current path.

Abstract: An insulation detector for highly accurately detecting or measuring, with a simple configuration, insulation resistance of a load or an apparatus to a ground or a housing and connected to an electric apparatus including one or both of an intra-apparatus capacitor and a battery, the insulation detector including an intra-insulation detector capacitor, a voltage detecting unit that detects a voltage of the intra-insulation detector capacitor, and a current-path forming switch for connecting the ground or the housing, the intra-apparatus capacitor, and the intra-insulation detector capacitor in series and forming a current path including insulation resistance of the electric apparatus. The insulation detector measures the insulation resistance by measuring a time constant of a change in the voltage of the intra-insulation detector capacitor.

Abstract: A CR snubber circuit capable of increasing a reduction effect of the effective inductance component and suppressing a ringing component generated at the time of switching the switching element is obtained. A first current path formed on one surface of the substrate and a second current path formed on the other surface, which is the opposite side of the one surface of the substrate, are opposed to each other with the substrate being sandwiched therebetween, and the capacitor 5 and the resistor 6 are arranged such that current flows in opposite directions in the first current path and the second current path, and a band elimination filter is formed by the capacitor 5, the register 6, and an effective inductance component obtained by coupling an inductance component included in the first current path and an inductance component included in the second current path.

Abstract: A drive circuit for a power semiconductor element includes: a voltage-command generation unit that generates a voltage command VGEref, which is a charge command between the gate and emitter terminals of a power semiconductor element; and a subtracter that calculates a deviation voltage Verr between the voltage command VGEref and the voltage between the gate and emitter terminals. The drive circuit also includes: a gate current controller that is input with the deviation voltage Verr and calculates a gate-current command voltage VIGref for determining the gate current that is caused to flow to the gate terminal of the power semiconductor element; a gate-current command limiter that limits the gate-current command voltage VIGref; and a gate-current supply device that is input with an actual gate-current command voltage VIGout and that supplies a gate current to the gate terminal of the power semiconductor element.

Abstract: A switching power supply circuit includes a switching element connected to a primary winding wire of a transformer in series, capacitors connected to secondary winding wires of the transformer via diodes, and an IC for power supply control that controls ON/OFF operation of the switching element on the basis of a charged voltage of the capacitors. Commanded voltages are charged in the capacitors after electric power is supplied to a main power supply, and further, after the elapse of a delay time set in advance, a control circuit, which controls the entire apparatus, controls a main circuit and a peripheral apparatus circuit to start operations.

Abstract: There are provided a smoothing capacitor (71) for storing an induced electromotive force generated by a three-phase induction motor (5), a regenerative transistor (81 to 86) for switching a terminal voltage of the smoothing capacitor to carry out a power regenerating operation over a three-phase AC power supply (3), a line voltage detecting portion (6) for detecting a line voltage of the three-phase AC power supply, a fundamental waveform generating portion (10) for generating, from a signal output from the line voltage detecting portion, a fundamental waveform defined to be a line voltage waveform of the three-phase AC power supply in which a source voltage distortion component is not mixed, a base driving signal creating portion (7) for creating a base driving signal to be used for an ON/OFF control of the regenerative transistor based on a signal output from the fundamental waveform generating portion, and a base driving signal output portion (9) for outputting the base driving signal.

Abstract: There are provided a smoothing capacitor (71) for storing an induced electromotive force generated by a three-phase induction motor (5), a regenerative transistor (81 to 86) for switching a terminal voltage of the smoothing capacitor to carry out a power regenerating operation over a three-phase AC power supply (3), a line voltage detecting portion (6) for detecting a line voltage of the three-phase AC power supply, a fundamental waveform generating portion (10) for generating, from a signal output from the line voltage detecting portion, a fundamental waveform defined to be a line voltage waveform of the three-phase AC power supply in which a source voltage distortion component is not mixed, a base driving signal creating portion (7) for creating a base driving signal to be used for an ON/OFF control of the regenerative transistor based on a signal output from the fundamental waveform generating portion, and a base driving signal output portion (9) for outputting the base driving signal.