Power conversion device and semiconductor module suitable for use in the device

An inverter device used to drive a vehicle on a trolley voltage of at least 1500 volt, comprising:

• a pair of d.c. terminals;
• a node at an intermediate potential between the potentials of said pair of d.c. terminals;
• a.c. terminals as many as the number of phases;
• a plurality of arms each connected between the d.c. terminal and the a.c. terminal, comprising two parallel circuit in series, each parallel circuit including an insulated gate bipolar transistor and a diode opposite in conducting direction to said insulated gate bipolar transistor, each of the parallel circuits connected between the d.c. terminal and the a.c. terminal;
• and
• a plurality of diodes each connected between a node of said two parallel circuits of the arm and, said node at a potential intermediate between the potentials of said pair of d.c. terminals.

An inverter device comprising:

• a pair of d.c. terminals;
• a node at a potential intermediate between the potentials of said pair of d.c. terminals;
• a.c. terminals as many as the number of phases;
• a plurality of arms each connected between the d.c. terminal and the a.c. terminal, comprising two parallel circuits in series, each parallel circuit including a switching device and a diode opposite in polarity to said switching device;
• and
• a plurality of diodes each connected between a node of the two parallel circuits of the arm and, said node at a potential intermediate between the potentials of said pair of d.c. terminals,
• wherein a lifetime of the switching device close to the d.c. terminal and at least one of the devices forming the parallel circuit having the diode opposite in polarity to the device is different from that of device forming the parallel circuit close to the a.c. terminal.

An inverter device comprising:

• a pair of d.c. terminals;
• a node at a potential intermediate between the potentials of said pair of d.c. terminals;
• a.c. terminals as many as the number of phases;
• a plurality of arms each connected between the d.c. terminal and the a.c. terminal, comprising two parallel circuits in series, each parallel circuit including an insulated gate bipolar transistor and a diode opposite in polarity to said insulated gate bipolar transistor;
• and
• a plurality of diodes each connected between a node of the two parallel circuits of the arm and, said node at a potential intermediate between the potentials of said pair of d.c. terminals,
• wherein one of the insulated gate bipolar transistors and diode of the parallel circuit of each arm is formed on a semiconductor substrate produced by Czochralski method.

An inverter device comprising:

• a pair of d.c. terminals;
• a.c. terminals equal to the number of phases of the inverter device;
• and
• a plurality of arms each connected between one of the d.c. terminals and one of the a.c. terminals, each arm comprising at least one parallel circuit, each parallel circuit including an insulated gate bipolar transistor and a diode opposite in conducting direction to said insulated gate bipolar transistor, each of the parallel circuits connected between the d.c. terminal and the a.c. terminal to which the corresponding arm is connected;
• wherein in at least one of said parallel circuits said diode has a recovery current of which a peak-to-peak value is at most 0.55 times a rated current of the insulated gate bipolar transistor of said at least one parallel circuit, and a recovery time in which the recovery current is attenuated from the peak-to-peak value to one tenth thereof is at least 0.75 times a resonance period obtained from a wiring inductance and a parasitic capacitance of said insulated bipolar transistor and said diode of said at least one parallel circuit.

An inverter device comprising:

• a pair of d.c. terminals;
• a.c. terminals equal to the number of phases of the inverter device;
• and
• a plurality of arms each connected between one of the d.c. terminals and one of the a.c. terminals, each arm comprising at least one parallel circuit, each parallel circuit including an insulated gate bipolar transistor and a diode opposite in conducting direction to said insulated gate bipolar transistor, each of the parallel circuits connected between the d.c. terminal and the a.c. terminal to which the corresponding arm is connected;
• wherein in at least one of said parallel circuits said diode includes a first semiconductor region of one conductivity type having one main surface, a second semiconductor region of a second conductivity type extending from a plurality of selected portions of said main surface into the inside of said first semiconductor region, a third semiconductor region of the second conductivity type extending from said main surface into the inside of said first semiconductor region and across adjacent portions of said second semiconductor region, said third semiconductor region having a depth smaller than that of said second semiconductor region, a first electrode formed on said main surface so as to form an ohmic junction with said second semiconductor region and form a Schottky junction with said third semiconductor region, and a second electrode provided so as to form an ohmic junction with said first semiconductor region.