Abstract: A motor driving circuit includes a three-phase inverter circuit 8, including three upper-arm switching elements 56a to 56c for driving upper arms of different phases of a three-phase motor 3, and three lower-arm switching elements 56d to 56f for driving lower arms of different phases. At least one of the upper-arm switching elements 56a to 56c and the lower-arm switching elements 56d to 56f is a semiconductor element that performs a diode operation. The diode operation is an operation in which a voltage less than or equal to a threshold voltage of a gate electrode G is applied to the gate electrode G with reference to a potential of a first ohmic electrode S, thereby conducting a current flow from the first ohmic electrode S to a second ohmic electrode D and blocking a current flow from the second ohmic electrode D to the first ohmic electrode S.

Abstract: A power conversion circuit includes a bidirectional switch 2. The bidirectional switch 2 has a first gate terminal G1, a second gate terminal G2, a first ohmic terminal S1 and a second ohmic terminal S2. The bidirectional switch 2 has four operation states. In the first state, the bidirectional switch 2 operates as a diode having a cathode as the first ohmic terminal S1 and an anode as the second ohmic terminal S2. In a second state, the bidirectional switch 2 operates as a diode having an anode as the first ohmic terminal S1 and a cathode as the second ohmic terminal S2. In a third state, the bidirectional switch 2 is bidirectionally conductive with via a diode between the first and second ohmic terminals S1 and S2. In a fourth state, the bidirectional switch 2 cuts off a bidirectional current between the first and second ohmic terminals.

Abstract: A heat exchange cooler capable of eliminating continuous radiation of high-frequency noise waves and reducing the man hour for the installation work, and a power circuit driving device used for it are provided. A commercial power transformer (311), which transforms commercial AC power (307) supplied from a heat generating element storing box to a specified range of voltage, is provided. Moreover, first relay (210) and second relay (212) are used for automatically switching a plurality of taps disposed at the coil of commercial power transformer (311) which keeps a wide range of commercial AC voltage from 200V to 250V in nominal voltage within a specified range of output voltage.

Abstract: A heat exchange cooler capable of eliminating continuous radiation of high-frequency noise waves and reducing the man hour for the installation work, and a power circuit driving device used for it are provided. A commercial power transformer (311), which transforms commercial AC power (307) supplied from a heat generating element storing box to a specified range of voltage, is provided. Moreover, first relay (210) and second relay (212) are used for automatically switching a plurality of taps disposed at the coil of commercial power transformer (311) which keeps a wide range of commercial AC voltage from 200V to 250V in nominal voltage within a specified range of output voltage.

Abstract: A power conversion circuit includes a bidirectional switch 2. The bidirectional switch 2 has a first gate terminal G1, a second gate terminal G2, a first ohmic terminal S1 and a second ohmic terminal S2. The bidirectional switch 2 has four operation states. In the first state, the bidirectional switch 2 operates as a diode having a cathode as the first ohmic terminal S1 and an anode as the second ohmic terminal S2. In a second state, the bidirectional switch 2 operates as a diode having an anode as the first ohmic terminal S1 and a cathode as the second ohmic terminal S2. In a third state, the bidirectional switch 2 is bidirectionally conductive with via a diode between the first and second ohmic terminals S1 and S2. In a fourth state, the bidirectional switch 2 cuts off a bidirectional current between the first and second ohmic terminals.

Abstract: A motor driving circuit includes a three-phase inverter circuit 8, including three upper-arm switching elements 56a to 56c for driving upper arms of different phases of a three-phase motor 3, and three lower-arm switching elements 56d to 56f for driving lower arms of different phases. At least one of the upper-arm switching elements 56a to 56c and the lower-arm switching elements 56d to 56f is a semiconductor element that performs a diode operation. The diode operation is an operation in which a voltage less than or equal to a threshold voltage of a gate electrode G is applied to the gate electrode G with reference to a potential of a first ohmic electrode S, thereby conducting a current flow from the first ohmic electrode S to a second ohmic electrode D and blocking a current flow from the second ohmic electrode D to the first ohmic electrode S.

Abstract: A heat exchange cooler capable of eliminating continuous radiation of high-frequency noise waves and reducing the man hour for the installation work, and a power circuit driving device used for it are provided. A commercial power transformer (311), which transforms commercial AC power (307) supplied from a heat generating element storing box to a specified range of voltage, is provided. Moreover, first relay (210) and second relay (212) are used for automatically switching a plurality of taps disposed at the coil of commercial power transformer (311) which keeps a wide range of commercial AC voltage from 200V to 250V in nominal voltage within a specified range of output voltage.