Abstract: A power conversion device includes a power converter to output AC power by converting input DC power, an electric leakage detector to detect electric leakage in a power supply line through which the AC power output by the power converter flows when the AC power is being output by the power converter, and a power conversion controller configured to control power conversion of the power converter. The power conversion controller is configured to stop power conversion operation of the power converter based on a detection result of the electric leakage detector.

Abstract: A power conversion device includes a power converter, a relay, and a welding detector. The welding detector includes a first resistor connected to a terminal of the relay on a first side, a capacitor and a second resistor, both of which are connected to a terminal of the relay on a second side, an application unit to apply an inspection signal to the relay via the capacitor and the second resistor, and a determiner connected between the capacitor and the second resistor, the determiner detecting a signal based on application of the inspection signal by the application unit to determine whether or not the relay is welded.

Abstract: A power conversion device includes a filter circuit unit between a power conversion unit and a smoothing capacitor for smoothing a pulsating flow accompanying power conversion in the power conversion unit to absorb at least a part of a high-frequency component of the pulsating flow.

Abstract: A power conversion device includes an electric leakage detector, a failure determiner to output a pulse current to reproduce, in a simulated manner, electric leakage, and a power conversion controller configured to control power conversion. The power conversion controller is configured to determine a failure of the electric leakage detector depending on whether or not a pulse width of a pulse current as an electric leakage detection signal acquired by the electric leakage detector is within a predetermined range.

Abstract: A power conversion device includes a power converter to output AC power by converting input DC power, an electric leakage detector to detect electric leakage in a power supply line through which the AC power output by the power converter flows when the AC power is being output by the power converter, and a power conversion controller configured to control power conversion of the power converter. The power conversion controller is configured to stop power conversion operation of the power converter based on a detection result of the electric leakage detector.

Abstract: The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method including: making a semiconductor device that is connected parallel to a load by a load cable, perform a switching operation; measuring common-mode current flowing through the load cable during the switching operation; and outputting an evaluation benchmark for radiated noise based on the common-mode current, and an evaluation apparatus are provided.

Abstract: A power conversion device includes a power converter, a relay, and a welding detector. The welding detector includes a first resistor connected to a terminal of the relay on a first side, a capacitor and a second resistor, both of which are connected to a terminal of the relay on a second side, an application unit to apply an inspection signal to the relay via the capacitor and the second resistor, and a determiner connected between the capacitor and the second resistor, the determiner detecting a signal based on application of the inspection signal by the application unit to determine whether or not the relay is welded.

Abstract: The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method and an evaluation apparatus are provided, including: causing a semiconductor device to perform a switching operation; measuring voltage variation occurring between main terminals of the semiconductor device during the switching operation; and outputting an evaluation benchmark for radiated noise of the semiconductor device based on the voltage variation. The outputting the evaluation benchmark may include calculating the voltage variation in the semiconductor device for each frequency component as the evaluation benchmark.

Abstract: The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method including: making a semiconductor device that is connected parallel to a load by a load cable, perform a switching operation; measuring common-mode current flowing through the load cable during the switching operation; and outputting an evaluation benchmark for radiated noise based on the common-mode current, and an evaluation apparatus are provided.

Abstract: The radiated noise of a semiconductor device is conveniently evaluated, and the radiated noise of an apparatus equipped with the semiconductor device is estimated. An evaluation method and an evaluation apparatus are provided, including: causing a semiconductor device to perform a switching operation; measuring voltage variation occurring between main terminals of the semiconductor device during the switching operation; and outputting an evaluation benchmark for radiated noise of the semiconductor device based on the voltage variation. The outputting the evaluation benchmark may include calculating the voltage variation in the semiconductor device for each frequency component as the evaluation benchmark.

Abstract: A motor drive device includes a bridge circuit 10 having a plurality of legs with switch elements 101 in upper and lower arms. High frequency AC voltage output from the bridge circuit 10, when it is connected to an AC power supply 1, is converted into a DC voltage via a transformer 21 and an AC/DC conversion circuit 11, thus charging the battery 2. Also, the DC voltage of the battery 2 is converted into an AC voltage by the bridge circuit 10 when the AC power supply 1 is cut off from the bridge circuit 10, and supplied to the alternating current motor 3. Because of this, the isolating transformer 21 can be driven at high frequency while the motor driving power conversion circuit is also used for battery charging, and a reduction in size and reduction in cost of the overall device are achieved.

Abstract: A power factor correction circuit includes a rectifier that rectifies AC power supply voltage, a series circuit of an inductor and a semiconductor switch connected between the rectifier circuit output terminals, and a series circuit of a diode and a smoothing capacitor connected to both ends of the semiconductor switch, a load connected to both ends of the smoothing capacitor, so that the power factor on the input side of the rectifier circuit is corrected by the switching operation of the semiconductor switch. This power factor correction circuit includes a control circuit that controls the switching frequency of the semiconductor switch such that the switching frequency becomes maximum when the ripple of a current flowing through the inductor becomes maximum. According to this power factor correction circuit, normal mode noise can be reduced, and the size of a filter circuit can be decreased.

Abstract: A power factor correction circuit includes a rectifier that rectifies AC power supply voltage, a series circuit of an inductor and a semiconductor switch connected between the rectifier circuit output terminals, and a series circuit of a diode and a smoothing capacitor connected to both ends of the semiconductor switch, a load connected to both ends of the smoothing capacitor, so that the power factor on the input side of the rectifier circuit is corrected by the switching operation of the semiconductor switch. This power factor correction circuit includes a control circuit that controls the switching frequency of the semiconductor switch such that the switching frequency becomes maximum when the ripple of a current flowing through the inductor becomes maximum. According to this power factor correction circuit, normal mode noise can be reduced, and the size of a filter circuit can be decreased.

Abstract: A motor drive device includes a bridge circuit 10 having a plurality of legs with switch elements 101 in upper and lower arms. High frequency AC voltage output from the bridge circuit 10, when it is connected to an AC power supply 1, is converted into a DC voltage via a transformer 21 and an AC/DC conversion circuit 11, thus charging the battery 2. Also, the DC voltage of the battery 2 is converted into an AC voltage by the bridge circuit 10 when the AC power supply 1 is cut off from the bridge circuit 10, and supplied to the alternating current motor 3. Because of this, the isolating transformer 21 can be driven at high frequency while the motor driving power conversion circuit is also used for battery charging, and a reduction in size and reduction in cost of the overall device are achieved.