A power conversion device includes a power switching circuit that supplies AC voltages generated between switching elements operating as upper arms and switching elements operating as lower arms, and a control circuit that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements by a PWM method in a first operational region in which frequency of an AC power to be outputted is low, and that generates and supplies to the driver circuit signals for controlling the switching operation of the switching elements at timings based upon the phase of the AC power to be outputted in an operational region in which the frequency of the AC power to be outputted is higher than in the first operational region.

Power Conversion Device

An object of the present invention is to improve the cooling performance of a capacitor module used in a power conversion apparatus. The power conversion apparatus according to the present invention includes a power semiconductor module, a capacitor module, a flow path forming body that forms a flow path through which a cooling refrigerant flows . The flow path forming body includes a first flow path forming body that forms a first flow path part for cooling the power semiconductor module, and a second flow path forming body that forms a second flow path part for cooling the capacitor module. The first flow path forming body is provided on a side portion of the second follow path forming body and is integrally formed with the second flow path forming body. The second flow path forming body forms a housing space for housing the capacitor module above the second flow path part . The first flow path part is formed at a position facing the side wall that forms the housing space. The power semiconductor module is inserted into the first flow path part.

Power Conversion Apparatus

A semiconductor power converting apparatus includes a semiconductor element for controlling a current flowing between a collector and an emitter in response to a gate condition, a driving device connected to the gate, for driving the gate in response to a drive signal entered thereinto, a voltage applying device for applying both a forward bias and a reverse bias to the gate so as to set the emitter of the semiconductor element to a neutral potential, and a voltage dividing device for dividing a voltage appearing between the collector and the emitter of the semiconductor element, in which the drive signal is under OFF state, a voltage produced based upon the divided voltage by the voltage dividing device is applied to the gate, and the gate voltage is controlled in response to the voltage appearing between the collector and the emitter of the semiconductor element, thereby reducing the snubbed loss.

Semiconductor power converting apparatus

A switching power supply device includes a full-bridge circuit, a transformer, a rectifier circuit, a filter circuit, a first series connection of a snubber capacitor and a first diode, and a second diode. The full-bridge circuit includes switching elements which are controlled to be driven under phase-shift control. The first series connection is connected in parallel with the smoothing reactor, where one terminal is connected to a terminal on positive side of the rectifier circuit, and the other terminal is connected to an anode of the first diode. A cathode of the first diode is connected to one terminal of the smoothing capacitor which is applied with positive voltage. The second diode is provided between a terminal on negative side of the rectifier circuit and a connecting point of the snubber capacitor and the first diode. A cathode of the second diode is connected to the connecting point.

Switching power supply device

In a DC power supply including a transformer, for making a semiconductor switch operate with a high frequency, an auxiliary circuit that reduces switching loss and a countermeasure circuit for a surge voltage generated in a rectifier diode are provided. In a DC power supply in which a DC power source 101 and a transformer T are connected via a power conversion circuit and a secondary winding of the transformer T is connected to a load RL via a rectifier diode bridge and a filter circuit to supply power to the load RL, a resonance reactor Lz is provided on an output side of the transformer T, a resonant switch circuit 103 including a parallel circuit of a diode Dz and a semiconductor switch Qz and a resonant capacitor Cz is connected in parallel to the rectifier diode bridge and a snubber circuit including a snubber capacitor Cs, a snubber diode Ds1 and a diode Ds2 for discharge is connected to a serial resonant circuit including the resonance reactor Lz and the resonant capacitor Cz in the resonant switch circuit 103 to absorb a surge voltage.

DC power supply

PURPOSE: To suppress the application of overvoltage to a rectifier diode by connecting a series circuit of capacitor and diode in parallel with a smoothing reactor or by like means. CONSTITUTION: A DC power supply 1 is connected with the primary winding of a transformer 3 via a switching circuit 2, and with a load 8 from the secondary winding of said transformer via a full-wave rectifier circuit by rectifier diodes 41∼44 and a smoothing filter circuit by smoothing reactor 6 and capacitor 7. Then, a series circuit of capacitor 9 and diode 10 is connected in parallel with said smoothing reactor 6, and that of reactor 11 and diode 12 is connected between the junction of said capacitor 9 and diode 10 and the output end of said rectifier circuit, with which end the smoothing reactor 6 is not connected. Thus, the energy stored in the input side inductance at the OFF-time of said rectifier diodes is absorbed by said capacitor 9 and discharged into the load via a reactor 11 so that a loss in snubber circuit is eliminated. COPYRIGHT: (C)1989,JPO&Japio

Snubber circuit for dc power supply

PURPOSE:To eliminate the need for a semiconductor switch having high breakdown voltage by connecting a voltage clamp circuit, comprising a clamp diode and a clamp capacitor, in parallel with a snubber capacitor. CONSTITUTION:This snubber energy recovering circuit is different from a conventional circuit in that a positive pole side voltage clamp circuit 31, comprising a clamp capacitor(CC) 31C and a clamp diode(CD) 31D, is connected in parallel with a snubber capacitor(SC) 8C. A third energy recovery circuit 42, comprising a third recovery diode 42D and a third recovery reactor 42L, is inserted between the CC 31C and the negative pole side of a DC power supply 2. A negative pole side voltage clamp circuit 41, comprising a CC 41C and a CD 41D, is connected in parallel with an SC 9C. A fourth energy recovery circuit 32. comprising a fourth recovery diode 32D and a fourth recovery reactor 32L, is inserted between the CC 41C and the positive pole side of the DC power supply 2. When the voltage of the SC 9C exceeds that of the CC 41C, the CD 41D is conducted and the voltage of a semiconductor switch 4 is restricted to the same level as that of the CC 41C.

Kazuo Kuroki

Papers

Snubber circuit for dc power supply

Snubber energy recovery circuit for power converter