Abstract: A PWM inverter in which high-surge voltage is not applied across terminals of a switching device thereof is provided by preventing multi-phase simultaneous switching.

Abstract: An insulated gate bipolar transistor and a protective circuit are incorporated. The protective circuit has first and second Zener diodes connected in series in directions opposite to each other between the gate and the current sense terminal of the insulated gate bipolar transistor, and third and fourth Zener diodes connected in series in directions opposite to each other between the gate and the emitter of the insulated gate bipolar transistor.

Abstract: An inrush current limiting circuit, a power source device, and a power conversion device. The circuit and devices limit an inrush current with high reliability and durability while reducing overall weight and volume of the device even under a high rated power. A switch, a capacitor, and a switching element are connected in series to one another, and the serial circuit formed thereof is connected to the main power source. An inverter is connected to the capacitor. A serial circuit formed of a capacitor and a resistor is connected between a collector and a gate of the switching element. A drive circuit drives a switching element to turn ON when the switch turns ON.

Abstract: A power conversion device that limits an inrush current while reducing overall weight and volume of the device even under a high rated power. One and the other ends of an initial charging circuit having a DC power source, a switch, and a diode connected in series are connected to an inductive load and a lower potential source line, respectively in a power conversion device. The initial charge controller unit turns ON and OFF one switching element of the power conversion device repeatedly during an initial charging operation prior to the normal operation. As a result, a charging current flowing through the initial charging circuit is supplied to a capacitor through the inductive load repeatedly. After the capacitor is sufficiently charged, the initial charging operation is finished and the normal operation is started.

Abstract: The present invention relates to a power conversion device. It is an object of the present invention to limit an inrush current while reducing overall weight and volume of the device even under a high rated power. In order to achieve the object, one and the other ends of an initial charging circuit (6) having a DC power source (16), a switch (18) and a diode (19) connected in series are connected to an inductive load (50) and a lower potential source line (NN), respectively in a power conversion device. The initial charge controller unit (70) turns ON and OFF one switching element (24) of the power conversion device repeatedly during an initial charging operation prior to the normal operation. As a result, a charging current (ICHG) flowing through the initial charging circuit (6) is supplied to a capacitor (12) through the inductive load (50) repeatedly. After the capacitor (12) is sufficiently charged, the initial charging operation is finished and the normal operation is started.

Abstract: The present invention relates to an inrush current limiting circuit, a power source device and a power conversion device. It is an object of the present invention to limit an inrush current with high reliability and durability while reducing overall weight and volume of the device even under a high rated power. In order to achieve the object, a switch (11) a capacitor (12) and a switching element (30) are connected in series to one another, and the serial circuit formed thereof is connected to the main power source (10). An invester 13 is connected to the capacitor (12). A serial circuit formed of a capacitor (32) and a resistor (33) is connected between a collector and a gate of the switching clement (30). A drive circuit (20) drives the switching clement (30) to turn ON when the switch (11) turns ON.

Abstract: To prevent malfunction or breakdown due to a surge voltage in a power converter for converting DC into AC or the like so as to supply electric power to a load, not only a control signal is transmitted via a level shift circuit which is provided correspondingly to each of switching semiconductor elements forming a main circuit and shifts a level of a reference potential at its output side so as to follow variations of a reference potential of the switching semiconductor element to the switching semiconductor element, but a DC control power source for supplying electric power to the level shift circuit and a negative pole of the switching semiconductor element are connected to each other through at least one of an inductor and a resistance.

Abstract: To prevent malfunction or breakdown due to a surge voltage in a power converter for converting DC into AC or the like so as to supply electric power to a load, not only a control signal is transmitted via a level shift circuit which is provided correspondingly to each of switching semiconductor elements forming a main circuit and shifts a level of a reference potential at its output side so as to follow variations of a reference potential of the switching semiconductor element to the switching semiconductor element, but a DC control power source for supplying electric power to the level shift circuit and a negative pole of the switching semiconductor element are connected to each other through at least one of an inductor and a resistance.

Abstract: An inverter circuit to reduce a resistor for overcurrent detection and decrease the number of filters in an inverter circuit for supplying polyphase power. Transistors each having a current detection terminal and a protective diode for regenerative current are adopted as switching elements on an “L” side and their current detection terminals are connected in common to a resistor. Therefore, a voltage drop caused by a current flowing in the resistor becomes larger when an overcurrent flows in at least one of the transistors and further when an overcurrent flows in a switching element on an “H” side even if no overcurrent flows in any one of the transistors.

Abstract: Current sense voltages (VCSl˜VCSn), which are the detected values of n (≧2) IGBTs connected in parallel, are converted into digital form, and thereafter, are subjected to an operation processing. After the current sense voltages (VCSl˜VCSn) are converted into collector currents (Il˜In) by use of constants (Gl˜Gn and VOFFSETl˜VOFFSETn)(step 103), current deviations (&Dgr;Il˜&Dgr;In) respectively defined as differences of the collector currents (Il˜In) from the average (IAVG) thereof are calculated (step 104, 105). Drive control voltages (VDl˜VDn) are renewed by changes (&Dgr;VDl˜&Dgr;VDn) which are respectively obtained by multiplying the current deviations (&Dgr;Il˜&Dgr;In) by factors (Kij)(step 106, 107). The drive control voltage (VDl˜VDn) are converted into analogue form, and thereafter, supplied to n IGBTs as their gate voltages (VGE).

Abstract: A capacitive element is charged with no excessive flow of current so that a potential to effect the operation of a switching element can be obtained with stability. A capacitor (30) is charged with a circulating current from a load (40). On the charging path, a resistor (21) is provided in series to prevent an excessive flow of the charging current. Between terminals (V.sub.B, V.sub.S) of an upper-arm driving circuit (25) which receive a voltage to effect the operation of an IGBT (34) of an upper arm, the capacitor (30) and the resistor (21) are provided to suppress a decrease in potential (V.sub.B) at the terminal (V.sub.B).

Abstract: An inverter circuit to reduce a resistor for overcurrent detection and decrease the number of filters in an inverter circuit for supply polyphase power. Transistors each having a current detection terminal and a protective diode for regenerative current are adopted as switching elements on an “L” side and their current detection terminals are connected in common to a resistor. Therefore, a voltage drop caused by a current flowing in the resisytor becomes larger when an overcurrent flows in at least one of the transistors and further when an overcurrent flows in a switching element on an “H” side even if no overcurrent flows in any one of the transistors.