Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Kazutaka Takahashi

Kei Terada

Tetsuaki Nagano

Yasunobu Harada

Takashi Isoda

Kazuya Nakamura

Shigeo Jimbo

To provide an electric power conversion device that converts direct current power supplied from a direct-current power supply into alternating current power, the electric power conversion device includes six switching elements constituted by a voltage-driven transistor that uses a wide bandgap semiconductor and a diode, and a drive circuit that controls a voltage for driving the transistor at a time of turning off the switching elements based on a predetermined voltage profile specifying that the transistor is operated in a non-linear region.

Electric power conversion device and surge voltage suppressing method

In a servo controller according to the invention, a position feedback correction unit () calculates a first-axis position feedback signal (pmfb) based on a first-axis position (pm) as a self-axis position, and a second-axis position (pm) as an other-axis position; and a deviation between a model position (pa) and the first-axis position feedback signal (pmfb) is inputted from a subtracter () to a position control unit (), which performs positional control to output a velocity command. A velocity feedback correction unit () calculates a first-axis velocity feedback signal (wmfb) from a first-axis velocity (wm) as the self-axis velocity, and a second-axis velocity (wm) as the other-axis velocity; and the velocity control unit () adds a model velocity (wa) and the velocity command outputted from the position control unit (), and subtracts the first-axis velocity feedback signal (wmfb) therefrom, and outputs a feedback torque command (Tfb) based on the corrected velocity command.

Servo controller

In a motor control device according to the invention, upon velocity control of a motor, a superimposed signal generating unitoutputs a superimposed signal idh of a repetitive waveform, such as a triangular wave or a sine wave. A d-axis current command generating unitadds the superimposed signal idh generated by the superimposed signal generating unitto a d-axis current command idc*0 and outputs a d-axis current command idc*. An axial misalignment detecting unit(, and) receives the d-axis current command idc* and a q-axis current command iqc* and outputs an axial misalignment angle estimation value &#x394;&#x3b8;^. An axial misalignment correction unitreceives the axial misalignment angle estimation value &#x394;&#x3b8;^ and an actual detected position &#x3b8;m and outputs a position after correction &#x3b8;m'. Therefore, detection and correction can be performed in real time through calculation at a given timing during a normal operation.

Motor control device

A magnetic-pole detecting system for synchronous AC motors and a magnetic-pole detecting method therefor are provided. The magnetic-pole detecting system for synchronous AC motors includes a position detectorfor detecting the relative position between the moving elementand the stator of an AC motor; a phase-update command unitfor making a plurality of currents with different phases flow in coilsandso that the moving elementmoves to a plurality of stable points; a reversal command unitfor making currents flow in the coilsandso that the moving elementreverses from the previous direction in which the moving elementhas been moved by the phase-update command unit; a current cut-off command unitfor cutting off the currents flowing in the coilsandwhen the position-detectordetects a movement of the moving element; a reversal-determining unitfor determining, based on a position-detecting signal from the position-detector, a direction in which the moving element has moved based on the phase-update command unit, and for determining that the determined direction has reversed between the previous and the present instances; and a stable-point-simulator for simulating a stable point by means of the phase of the currents flowing in the moving elementwhen the reversal-determining unithas detected the reversal.

Growing community of inventors

Chiyoda-ku, Japan

Kazutaka Takahashi