Abstract: A control device includes a changing rate calculator, a first threshold calculator, and a separation determiner. The control device determines whether a current collector is separate from a power line, in a power conversion system in which a power converter converts power supplied from the current collector to the primary side of the power converter into alternating-current (AC) power and supplies the AC power to a motor connected to the secondary side of the power converter. The changing rate calculator calculates a changing rate of the voltage at the primary side of the power converter. The first threshold calculator calculates a first threshold having the absolute value positively correlated with an output power from the power converter. The separation determiner compares the changing rate with the first threshold and determines whether the current collector is separate from the power line.

Abstract: A vehicle control device includes a power converter that converts supplied direct current power and supplies the converted direct current power to a load device. A first voltage detector detects a first voltage that is a voltage of the power supply line. A second voltage detector detects a second voltage that is a voltage of the power converter on a side where a power supply source is provided. When a first contactor is closed and brought into a state allowing current to flow through the first contactor, if a decreasing amount of the first voltage from a first time ago to a present time is greater than or equal to a first threshold and a decreasing amount of the second voltage from a second time ago to the present time is greater than or equal to a second threshold, a contactor controller opens the first contactor.

Abstract: A control device includes a changing rate calculator, a first threshold calculator, and a separation determiner. The control device determines whether a current collector is separate from a power line, in a power conversion system in which a power converter converts power supplied from the current collector to the primary side of the power converter into alternating-current (AC) power and supplies the AC power to a motor connected to the secondary side of the power converter. The changing rate calculator calculates a changing rate of the voltage at the primary side of the power converter. The first threshold calculator calculates a first threshold having the absolute value positively correlated with an output power from the power converter. The separation determiner compares the changing rate with the first threshold and determines whether the current collector is separate from the power line.

Abstract: A vehicle control device includes a power converter that converts supplied direct current power and supplies the converted direct current power to a load device. A first voltage detector detects a first voltage that is a voltage of the power supply line. A second voltage detector detects a second voltage that is a voltage of the power converter on a side where a power supply source is provided. When a first contactor is closed and brought into a state allowing current to flow through the first contactor, if a decreasing amount of the first voltage from a first time ago to a present time is greater than or equal to a first threshold and a decreasing amount of the second voltage from a second time ago to the present time is greater than or equal to a second threshold, a contactor controller opens the first contactor.

Abstract: A room-warming/cooling and hot-water supplying heat-pump apparatus comprises a refrigerant circuit provided with a compressor, a four-way valve for switching room warming and cooling operations, a room side heat exchanger, a reversible flow type expansion device and an outdoor side heat exchanger, wherein a first switching means is connected to the outlet side of the compressor; a first branch of the switching means is connected to the four-way valve and a second branch of the first switching means is connected to one end of a heating coil in a hot water tank; the other end of the heating coil extends out of the hot water tank and has a branched part. A pipeline including the branched part has both ends connected to the refrigerant circuit at both sides of the expansion device in which at least one valve means is provided in the pipeline including the branched part and the first switching means and the valve means are controlled by a control device.