Abstract: A converter includes switching devices connected between each of a plurality of input ends and a DC power supply line, and switching devices connected between each of the plurality of input ends and a DC power supply line. A capacitor, a resistor and a diode are connected in series with each other between the DC power supply lines.

Abstract: A motor control unit (10) includes: a power converter (40) having a rectifier circuit (20) which rectifies an AC voltage from an AC power supply (31), a capacitor circuit (22) which receives an output of the rectifier circuit (20) and outputs a rectified voltage having pulses from both ends of a capacitor (13) and an inverter circuit (25) which receives the rectified voltage and outputs an AC voltage to the motor (30); and a motor controller (41) controlling the motor (30) by controlling the inverter circuit (25). The motor controller (41) performs torque control to vary an output toque of the motor (30) in response to variation in load torque of the motor (30).

Abstract: In the case where a chip is made of wide band gap semiconductor, a power conversion apparatus is obtained in which a component having a low heat resistant temperature is prevented from receiving thermal damage by heat generated at the chip. In a configuration including: a chip portion (20) including a chip (21) made of wide band gap semiconductor and a member (22, 23) having a heat resistant temperature equal to or higher than that of the chip (21); and a peripheral component (25) arranged in the vicinity of the chip portion (20) and having a heat resistant temperature lower than that of the chip (21). The chip (21) and the peripheral component (25) are thermally insulated from each other so that the temperature of the peripheral component (25) does not exceed the heat resistant temperature of the peripheral component (25).

Abstract: A voltage control rate of an inverter has a DC component and an AC component. This AC component has a frequency which is six times a fundamental frequency of an AC voltage outputted by the inverter. Even when there are not only a fifth-order harmonic component but also a seventh-order harmonic component of a load current, a ratio between the magnitude of the AC component and the DC component can be appropriately set.

Abstract: In a direct converting apparatus including a converter and a plurality of inverters, substantial carrier frequencies of the plurality of inverters are made different from each other while performing an operation in synchronization with the converter. An original carrier has a carrier frequency twice as high as a carrier frequency of a first carrier used for controlling one of the inverters. A waveform of the original carrier is magnified twice with a value serving as the center thereof, so that a second carrier used for controlling the other of the inverters is obtained.

Abstract: A plurality of capacitors are interposed between ones of a plurality of input lines. The clamp capacitor is connected between two DC power supply lines. A current-source converter includes a plurality of switch devices, where x represents r, s and t. The switch device selects conduction/non-conduction through a first diode between corresponding one of the input lines and the first DC power supply line and conduction/non-conduction through a second diode between said corresponding one of input lines and the second DC power supply line based on external signals and brings corresponding one of the input lines with the first and second DC power supply lines in a state of not receiving the signals.

Abstract: An output voltage of a converter is given to a pair of DC power supply lines. Inverters are connected in parallel with each other between the DC power supply lines. When one inverter is operated based on a first zero vector and the other inverter is operated based on a second zero vector, a commutation is caused in the converter. The first zero vector and the second zero vector are different from each other. For example, all of high-arm side switching elements of the one inverter and low-arm side switching elements of the other inverter are rendered non-conducting, and all of side switching elements of the one inverter and high-arm side switching elements of the other inverter are rendered conducting.

Abstract: A converter section converts a three-phase ac input voltage into a dc voltage, and an inverter section converts the dc voltage converted by the converter section into a prescribed three-phase ac output voltage. The converter section converts the three-phase ac input voltage into the dc voltage on the basis of trapezoidal waveform voltage instruction signals from a trapezoidal waveform voltage instruction signal generating part and a carrier signal from a carrier signal generating part. The inverter section converts the dc voltage converted by the converter section 1 into a prescribed three-phase ac output voltage on the basis of an inverter section instruction signal corrected by an instruction signal correcting part. The trapezoidal waveform voltage instruction signal generating part generates sloped regions of the trapezoidal waveform voltage instruction signals by using a prescribed table.

Abstract: Controlled by switching is which reactor in a reactor group present between a power source and a three-level converter is to be connected to an intermediate point that outputs a midpoint potential. In the switching, the closer to the command value of the midpoint potential the command values of input potentials of the converter are, the greater the duty at which corresponding reactors are connected to the intermediate point is for pulse width modulation. Additionally, a predetermined range to be compared with the command values has a predetermined potential width with respect to an AC waveform centered around the command value of the midpoint potential.

Abstract: The inverter comprises a diode bridge (21) that rectifies an inputted three-phase AC voltage into a DC voltage, an inverter section (22) that converts the DC voltage converted by the diode bridge (21) into an AC voltage and outputs the resulting voltage, an LC filter that has an inductor Ldc connected between one output terminal of the diode bridge (21) and one input terminal of the inverter section and a capacitor Cdc connected across the input terminals of the inverter section, a voltage detecting section (24) that detects cross terminal voltage of the inductor Ldc, and a control section (100) that controls the inverter section (22). The control section (100) controls the inverter section (22) so that the transfer characteristic of the I/O voltage of the inverter section (22) becomes a characteristic of the first-order lag system on the basis of the cross terminal voltage of the inductor Ldc detected by the voltage detecting section (24).

Abstract: Choppers are provided respectively in the output stages of two diode bridges, and their output sides are connected in parallel to a smoothing capacitor. By controlling the operations of the two choppers, the currents which are allowed to be inputted to the diode bridges are made triangular waves of mutually opposite phases, or middle-phase waveforms of three phases.

Abstract: A converter and an inverter are connected via a clamp circuit. The converter performs commutation in accordance with any of a first commutation mode in which trapezoidal waves are compared with a carrier and a 120-degree conduction mode. A diode of the clamp circuit is short-circuited by a shorting switch. The shorting switch is rendered conductive when a power factor reduces or a power supply voltage reduces, and capacitors of the clamp circuit are connected in series between DC power supply lines. The converter performs commutation in accordance with the 120-degree conduction mode, not in accordance with the first commutation mode, while the shorting switch is conductive.

Abstract: An output voltage command signal for outputting a specified three-phase ac output voltage is generated by a line voltage control command signal generating section, and a signal representing a current flow ratio is generated by a current flow ratio generating section based on a specified input current command signal. The output voltage command signal is corrected by a command signal computing section based on the output voltage command signal generated by the line voltage control command signal generating section and the signal representing the current flow ratio generated by the current flow ratio generating section. A PWM conversion signal is generated by a PWM conversion signal generating section based on the corrected output voltage command signal and a carrier signal. Based on the generated PWM conversion signal, a three-phase ac input voltage is converted into a specified three-phase ac input voltage by a conversion section.

Abstract: A control section controls a current-source converter in a state in which a switch is in conduction, and performs voltage doubler rectification on a voltage between a neutral phase input line and any of input lines to provide for charging of clamp capacitors. Accordingly, the clamp capacitors are charged through a resistor, which prevents an inrush current from flowing therethrough. In addition, a voltage between both ends of a pair of the clamp capacitors is higher than, for example, a voltage between both ends of a pair of capacitors. Accordingly, even if the clamp capacitors and, for example, the capacitors are electrically connected to each other in a normal operation, it is possible to prevent the inrush current from flowing from the capacitors to the clamp capacitors.

Abstract: A transistor is brought into conduction when, for example, a voltage between both ends of a second clamp capacitor exceeds a predetermined reference voltage. A resistance value of a discharge resistor is smaller than a value obtained by dividing the reference voltage by the maximum value of a current flowing through the discharge resistor. When the transistor is brought into conduction as a result of a voltage between both ends of the second clamp capacitor exceeding the predetermined reference voltage, a voltage applied to the discharge resistor, which results from a regenerative current, is larger one of the voltage between both ends of the second clamp capacitor and a voltage drop of the discharge resistor due to the regenerative current. The voltage drop and the voltage between both ends are smaller than a voltage between DC power supply lines, whereby it is possible to reduce an electrostatic capacitance of the discharge resistor.

Abstract: A current-source converter includes high-arm side switching elements and low-arm side switching elements. A voltage between the DC power supply lines is detected as a line voltage of an input line, based on a conduction pattern of the high-arm side switching elements and the low-arm side switching elements.

Abstract: A control section controls a current-source converter while a switch is conducting, to render conducting a pair of a high-aim side transistor and a low-arm side transistor (for example, transistors) which are connected to any one of input lines, performs voltage doubler rectification on a voltage between a neutral phase input line on which a resistor is provided and any one of the input lines, to serve for charging of clamp capacitors.

Abstract: A current control type converter has a converter section and a control section that includes three controllers. A first controller calculates and outputs an active current instruction value by proportional-plus-integral control to perform proportional integration of a deviation between the value of a DC voltage outputted from the converter section and a DC voltage instruction value. A second controller calculates and outputs an active voltage correction value by proportional-plus-integral control to perform proportional integration of a deviation between the active current instruction value from the first controller and the value of an active current inputted to the converter section. A third controller calculates and outputs a reactive voltage correction value by proportional-plus-integral control to perform proportional integration of a deviation between the value of a reactive current inputted to the converter section and a reactive current instruction value.

Abstract: A control section controls a current-source converter simultaneously with or prior to conduction of a power supply switch to connect a clamp capacitor and capacitors between a first input line on which a resistor is provided and any one of second and third input lines in parallel with each other. Accordingly, current is transmitted to the clamp capacitor via the resistor when the power supply switch is brought into conduction, which prevents inrush current from flowing to the clamp capacitor. In addition, for example, the capacitors are not charged prior to the clamp capacitor, whereby it is possible to prevent the inrush current from flowing from the capacitors to the clamp capacitor when they are connected in parallel with each other.

Abstract: A switch device is brought into conduction in a case where a carrier takes a value zero to drt, a switch device is brought into conduction in a case where the carrier takes a value the drt to one, and one cycle of the carrier is divided into a period in which the carrier has a command value or more and a period in which the carrier has the command value or less. The periods are calculated by dst·T and drt·T, respectively. The same one as the carrier of a converter is employed in a carrier of an inverter, and based on the value drt set as a reference value, a command value of the inverter is provided in each of a side with a value larger than the reference value and a side with a value smaller than the reference value. The period in which the carrier takes the value or more is divided at a ratio among d0, d4 and d6, and the period in which the carrier takes the value drt or less is divided at the ratio among d0, d4 and d6.