Abstract: A power conversion apparatus includes a power-conversion circuit unit that includes at least two voltage-type bridge circuits of an upper and lower arm configuration including switching elements connected in series, each of the switching elements including a transistor and a free wheel diode connected to the transistor in inverse parallel. Each of the voltage-type bridge circuits is configured to include, as the free wheel diodes: a SiC-SBD (SiC-Schottky-Barrier Diodes) in both upper and lower arms; a SiC-SBD only in the upper arm; a SiC-SBD only in the lower arm; or a diode other than the SiC-SBD in both the upper and lower arms; and the power-conversion circuit unit is configured by combining at least two configurations among the four configurations for the voltage-type bridge circuits.

Abstract: A power conversion device is provided in which destruction of a switching element can be avoided by preventing an excessive current from flowing into the switching element of a main circuit when, for example, a power supply for the power conversion device is interrupted. The power conversion device including a first switch unit in which a plurality of switching elements are series-connected is characterized by including, in the plurality of switching elements, at least one or more switching elements whose gate voltage thresholds are no more than a predetermined value and at least one or more switching elements whose gate voltage thresholds are more than the predetermined value.

Abstract: A power conversion apparatus includes a power-conversion circuit unit that includes at least two voltage-type bridge circuits of an upper and lower arm configuration including switching elements connected in series, each of the switching elements including a transistor and a free wheel diode connected to the transistor in inverse parallel. Each of the voltage-type bridge circuits is configured to include, as the free wheel diodes: a SiC-SBD (SiC-Schottky-Barrier Diodes) in both upper and lower arms; a SiC-SBD only in the upper arm; a SiC-SBD only in the lower arm; or a diode other than the SiC-SBD in both the upper and lower arms; and the power-conversion circuit unit is configured by combining at least two configurations among the four configurations for the voltage-type bridge circuits.

Abstract: A converter controllable in regenerative running mode, which is a power converting apparatus capable of suppressing harmonics without increasing the size of a reactor, and reducing power loss and electromagnetic noise. A power converter is configured by directly connecting AC sides of single-phase sub-converters having a DC voltage lower than a DC voltage of a 3-phase main converter to AC input lines of individual phases thereof in series. The main converter is driven by one gate pulse per half recurring cycle and a voltage produced by each sub-converter at AC terminals thereof is controlled to match a difference between an AC power supply voltage and a voltage produced by the main converter at AC terminals thereof, whereby phase voltages of the power converter are generated as the sums of phase voltages of the individual converters.

Abstract: A power conversion device including sub-inverters, each connected in series with respective phase of a three-phase main inverter including a smoothing capacitor, which is fed from a power supply via a converter, as a DC input thereof, and feeds power to a load using the sum of outputs of the inverters. A manipulative quantity is determined so that the DC voltage at each of smoothing capacitors which is an input of each of the sub-inverters will follow a command value. The manipulative quantity is added to an output voltage command for the three-phase main inverter, and is subtracted from an output voltage command for the sub-inverters. Thus, power is shifted from the three-phase main inverter to the smoothing capacitors of the sub-inverters.

Abstract: A converter controllable in regenerative running mode, which is a power converting apparatus capable of suppressing harmonics without increasing the size of a reactor, and reducing power loss and electromagnetic noise. A power converter is configured by directly connecting AC sides of single-phase sub-converters having a DC voltage lower than a DC voltage of a 3-phase main converter to AC input lines of individual phases thereof in series. The main converter is driven by one gate pulse per half recurring cycle and a voltage produced by each sub-converter at AC terminals thereof is controlled to match a difference between an AC power supply voltage and a voltage produced by the main converter at AC terminals thereof, whereby phase voltages of the power converter are generated as the sums of phase voltages of the individual converters.

Abstract: A power conversion device including sub-inverters, each connected in series with respective phase of a three-phase main inverter including a smoothing capacitor, which is fed from a power supply via a converter, as a DC input thereof, and feeds power to a load using the sum of outputs of the inverters. A manipulative quantity is determined so that the DC voltage at each of smoothing capacitors which is an input of each of the sub-inverters will follow a command value. The manipulative quantity is added to an output voltage command for the three-phase main inverter, and is subtracted from an output voltage command for the sub-inverters. Thus, power is shifted from the three-phase main inverter to the smoothing capacitors of the sub-inverters.

Abstract: An apparatus for controlling a power converter including a voltage-vector control unit that determines, based on voltage instruction value for the power converter, a voltage vector output from a power converter in one control cycle of pulse width modulation control and times for outputting of the voltage vector, a voltage-vector adjusting unit that adjusts the time of outputting of the voltage vector so that time of outputting of a zero-voltage vector is larger than a fixed time or zero, and a firing-pulse generating unit that generates a signal for turning on and off a semiconductor switching element included in the power converter, based on the time of outputting of the voltage vector adjusted by the voltage-vector adjusting unit.

Abstract: An apparatus for controlling a power converter including a voltage-vector control unit that determines, based on voltage instruction value for the power converter, a voltage vector output from a power converter in one control cycle of pulse width modulation control and times for outputting of the voltage vector, a voltage-vector adjusting unit that adjusts the time of outputting of the voltage vector so that time of outputting of a zero-voltage vector is larger than a fixed time or zero, and a firing-pulse generating unit that generates a signal for turning on and off a semiconductor switching element included in the power converter, based on the time of outputting of the voltage vector adjusted by the voltage-vector adjusting unit.

Abstract: The invention is an induction motor controller for measuring electrical constants of a polyphase induction motor (102) by supplying test power thereto and controlling driving of the polyphase induction motor with a polyphase inverter (105) by using parameters for controlling driving of a result of the measurement.

Abstract: A control device for a PWM controlled converter having a voltage control portion for comparing with a voltage set value a detected value of a DC voltage output from the PWM controlled converter, connected through reactors to a 3-phase AC power source, for controlling AC input currents supplied from the 3-phase AC power source, to thereby produce current reference signals; an AC reference signal generating portion for generating AC reference signals synchronized with the 3-phase AC power source; a current instruction portion for producing current instruction signals formed by varying the amplitudes of the AC reference signals output from the AC reference signal generating portion in accordance with the current reference signals, and a current control portion for producing control signals to the PWM controlled converter so that the AC input currents vary as instructed by the current instruction signals.

Abstract: A control unit for an induction motor which detects a primary current in an induction motor, obtains an error current which becomes zero when an actual value of the primary magnetic flux coincides with a set value provided as a product of I.sub.1d * and a primary self inductance L.sub.1, executes correction of the primary resistance, primary self-inductance, and leak factor according to the error current. Furthermore, the control unit has a correcting section control circuit in which a set error most influential for effecting coincidence between the primary magnetic flux in the induction motor with the primary magnetic flux is preferentially corrected.

Abstract: An error current component which becomes zero when an actual value of a primary flux coincides with a set value inducted by a product of an exciting current command and a primary self-inductance by detecting a primary current of an inductance motor, is inducted by an error current component processing circuit. A primary resistance compensation circuit processes a compensation amount of a primary resistance compensation amount. And a compensation voltage processing circuit processes a compensation voltage which directs the error current component to zero. A rotating speed of the induction motor can be controlled in a stable state even though a value of primary resistance of the induction motor is varied by temperature. Further, inadequate torque and excess current can be avoided.

Abstract: An object of the invention is to provide a control device of an induction motor where an inverter circuit can be protected from overcurrent by stable current limitation operation not only at steady operation but also at rapid acceleration/deceleration or at regenerative braking. A current component calculation circuit calculates a first current component from primary current detected by a current detector and output frequency. A correction frequency calculation circuit calculates a frequency correction value using a current limit value and the first current component according to prescribed function calculation. A subtractor subtracts the frequency correction value from a primary frequency command value. A voltage component calculation circuit calculates a primary voltage component command value according to the subtracted output.