Mitsubishi Denki Kabushiki Kaisha

Other

Mitsubishi Denki K.k.

Masahiko Iwasaki

Masato Koyama

Akira Imanaka

Masayuki Katto

Yuzuru Tunehiro

Masakatu Daijo

An inverter apparatus and a transport system using the same comprises a pair of current detectors for detecting output currents of at least two phases of output currents of three phases, a pair of converters for converting detected currents to two axes extending perpendicularly to each other, which are rotated in synchronism with output frequency of the inverter apparatus by an orthogonal projection, a computer for adding frequency correcting set frequency with respect to output voltage and the set frequency set from the outside, in accordance with current converted to the two axes, and for deciding predetermined output voltage and output frequency by the set frequency regardless of the current, and a switch in which ON/OFF can be assigned from the outside.

Inverter apparatus having two control modes and apparatus using the same

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.

Controller for induction motor

An inverter control apparatus includes a current detector for detecting currents of two phases from among output currents of an inverter that drives an induction motor, a current coordinate converter for converting currents detected by the current detector to a torque current component and an exciting current component, a computing device for computing the output frequency of the inverter corrected on the basis of a discrepancy proportional to the difference between an exciting current set value and an exciting current by using the torque current component and the exciting current component obtained by the current coordinate converter and for computing a torque voltage component and an exciting voltage component of the output voltage in synchronization with this output frequency, a voltage coordinate converter for converting the torque voltage component and the exciting voltage component computed by the computing device to a three-phase AC voltage of the output frequency of the inverter, and a PWM controller for generating switching control signals of the inverter on the basis of the three-phase AC voltage obtained by the voltage coordinate converter.

Inverter control apparatus

An inverter control apparatus contrived for improving the torque characteristic of an induction motor, wherein a current inputted to the induction motor is continuously detected, and the output voltage of the inverter is corrected by a voltage corresponding to a variation in the detected current.

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Nagoya, Japan

Masahiko Iwasaki