Abstract: A temperature detection method for a semiconductor device and a power conversion apparatus are disclosed. A temperature detection device is used to detect the temperature for thermal protection of a power semiconductor device. The temperature detection device is placed in the proximity of a component having the power semiconductor device packaged therein, and either an emitter terminal or a collector terminal of the power semiconductor device. Since the temperature detection device is mounted on a circuit board, it does not require insulation from a cooling fin on which the power semiconductor device is mounted and lead wires can be eliminated.

Abstract: In the present invention, miniaturization of an electric power conversion system is made possible while the reduction of a rise in temperature is achieved through a cooling operation by a cooling fan. The electric power conversion system is provided with a casing for covering cooling fins for cooling power semiconductors, a main circuit board having a driver circuit for driving the power semiconductors, and a cover for covering up the main circuit board. The system includes a first airflow hole provided at a part of the main circuit board, on the upper side of an air-intake provided in the cover, and a second airflow hole provided on the lower side of the first airflow hole, and on the lower side of the cooling fins, wherein air from the second airflow hole is driven to the cooling fins by a cooling fan.

Abstract: For applications in a facility where a power conversion apparatus is frequently started and stopped, a power conversion apparatus and a power cycle longevity estimation method are provided which improve an ease of use of the facility. The power conversion apparatus comprises power conversion circuits to supply ac power of variable voltage and variable frequency, a detection circuit to detect a temperature of the power semiconductor in the power conversion circuits, and a computation device to calculate a power cycle longevity of the power semiconductor based on a maximum temperature rise detected by the detection circuit.

Abstract: A frequency converter in which the inductance is reduced by enlarging the forms of bus bars which connect a P phase, an N phase of an inverter part and a positive electrode or a negative electrode of smoothing capacitors and the form of a wiring bus bar which connects an intermediate layer of capacitors which are connected in series to enlarge areas where they overlap each other, and by making currents flow in the opposite directions to each other.

Abstract: The present invention provides an electric power converter in which a tip portion of a cooling fin on an air flow inlet side is limited to flow a large quantity of air around a connection portion, where the fin efficiency is high, of a base surface of the cooling fin and the fin so that the cooling efficiency of the cooling fin can be improved. By providing the limiting member, air or atmosphere flowing into the cooling fin is directed to flow toward the fin near the base surface. Further, by providing the limiting member, an area of a portion from which the air or atmosphere flows into the cooling fin is also limited so that the velocity of the air or atmosphere flow becomes high. By these functions and the like, the cooling efficiency of the cooling fin can be increased as compared to the prior art.

Abstract: In the present invention, miniaturization of an electric power conversion system is made possible while the reduction of a rise in temperature is achieved through a cooling operation by a cooling fan. The electric power conversion system is provided with a casing for covering cooling fins for cooling power semiconductors, a main circuit board having a driver circuit for driving the power semiconductors, and a cover for covering up the main circuit board. The system includes a first airflow hole provided at a part of the main circuit board, on the upper side of an air-intake provided in the cover, and a second airflow hole provided on the lower side of the first airflow hole, and on the lower side of the cooling fins, wherein air from the second airflow hole is driven to the cooling fins by a cooling fan.

Abstract: For applications in a facility where a power conversion apparatus is frequently started and stopped, a power conversion apparatus and a power cycle longevity estimation method are provided which improve an ease of use of the facility. The power conversion apparatus comprises power conversion circuits to supply ac power of variable voltage and variable frequency, a detection circuit to detect a temperature of the power semiconductor in the power conversion circuits, and a computation device to calculate a power cycle longevity of the power semiconductor based on a maximum temperature rise detected by the detection circuit.

Abstract: The present invention provides an electric power converter in which a tip portion of a cooling fin on an air flow inlet side is limited to flow a large quantity of air around a connection portion, where the fin efficiency is high, of a base surface of the cooling fin and the fin so that the cooling efficiency of the cooling fin can be improved. By providing the limiting member, air or atmosphere flowing into the cooling fin is directed to flow toward the fin near the base surface. Further, by providing the limiting member, an area of a portion from which the air or atmosphere flows into the cooling fin is also limited so that the velocity of the air or atmosphere flow becomes high. By these functions and the like, the cooling efficiency of the cooling fin can be increased as compared to the prior art.

Abstract: A frequency converter in which the inductance is reduced by enlarging the forms of bus bars which connect a P phase, an N phase of an inverter part and a positive electrode or a negative electrode of smoothing capacitors and the form of a wiring bus bar which connects an intermediate layer of capacitors which are connected in series to enlarge areas where they overlap each other, and by making currents flow in the opposite directions to each other.

Abstract: An electric circuit module comprising: an electric device comprising an electric circuit to serve for passage and interruption of electric current, a packing material packing the electric circuit and a plurality of wiring members to electrically connect the electric circuit with an external circuit; and a heat sink to radiate heat from the electric device. The electric circuit module includes a fixture to fix the heat sink and the electric device together so that a heat radiating surface of the electric device comes into contact with the heat sink. The fixture is formed with a recess to accommodate therein a part of the electric device so that the heat radiating surface of the electric device is exposed from the fixture. When the electric device is fixed to the heat sink by the fixture, the heat radiating surface comes into contact with the heat sink.

Abstract: There is provided a temperature detection method of a semiconductor device that is small and low-cost and a power conversion apparatus that is small and low-cost. Temperature detection for thermal protection of a power semiconductor device is performed by a temperature detection device placed in the proximity to a component having the power semiconductor device packaged therein and in the proximity to one of an emitter terminal and a collector terminal of the power semiconductor device. As the temperature detection device can be mounted on a circuit board, it is not necessary to insulate the temperature detection device electrically from a cooling fin on which the power semiconductor device is placed and there is no need for lead wires and man-hours for wiring the lead wires. Therefore, it is possible to inexpensively realize the thermal protection of the power semiconductor device in the power conversion apparatus.

Abstract: An electric circuit module comprising: an electric device comprising an electric circuit to serve for passage and interruption of electric current, a packing material packing the electric circuit and a plurality of wiring members to electrically connect the electric circuit with an external circuit; and a heat sink to radiate heat from the electric device. The electric circuit module includes a fixture to fix the heat sink and the electric device together so that a heat radiating surface of the electric device comes into contact with the heat sink. The fixture is formed with a recess to accommodate therein a part of the electric device so that the heat radiating surface of the electric device is exposed from the fixture. When the electric device is fixed to the heat sink by the fixture, the heat radiating surface comes into contact with the heat sink.

Abstract: An inverter device and a motor driving device are arranged to have an inrush current prevention circuit for preventing an inrush current from flowing into a smoothing circuit when the power is turned on. The inrush current prevention circuit includes a current limiter for limiting the inrush current, a plurality of semiconductor switching elements, and an inrush current prevention circuit driving -circuit for driving the plurality of semiconductor switching elements, the semiconductor switching elements being connected together.

Abstract: An inverter device and a motor driving device are arranged to have a rush preventing circuit for preventing rush current from being flown in a smoothing circuit when the power is turned on. The rush preventing circuit includes a current-limiting means for limiting rush current, a plurality of semiconductor switching elements, a rush preventing circuit driving circuit for driving these semiconductor switching elements, and those semiconductor switching elements being connected in parallel to each other.

Abstract: An inverter device and a motor driving device are arranged to have an inrush current prevention circuit for preventing an inrush current from flowing into a smoothing circuit when the power is turned on. The inrush current prevention circuit includes a current limiter for limiting the inrush current, a plurality of semiconductor switching elements, and an inrush current prevention circuit driving—circuit for driving the plurality of semiconductor switching elements, the semiconductor switching elements being connected together.