Hitachi, Ltd.

Takefumi Sawada

Ryoso Masaki

Satoru Kaneko

Hirokazu Matsui

Hiroshi Katayama

Shigeyuki Yoshihara

Mitsuyuki Hombu

Hiroshi Katada

Masamichi Nawa

There is provided an AC motor controller capable of detecting an abnormal state of a motor cable while an AC motor is operating without using a special circuit but using a processor. The AC motor controller includes an AC motor; an inverter for driving the AC motor with a motor current through a motor cable; and a motor current detector for detecting the motor current flowing in the motor cable of the AC motor, in which a processor detects an abnormal state of the motor cable such as an inter-phase short circuit and an open circuit based on the motor current detected by the motor current detector.

AC motor controller

An electric power converter which has improved accuracy in compensation of a dead time. A motor driving system employing the electric power converter is also provided. A power module includes a plurality of switching devices connected in series and converts DC power to AC power. A control circuit produces a voltage command value in accordance with a control command inputted from the exterior, and produces gate signals to drive the switching devices of the power module corresponding to a final voltage command value which is obtained from the voltage command value with dead time compensation. A dead time compensation logic circuit calculates a final dead time compensation voltage based on a change rate of the voltage command value, a gain (dead time compensation voltage value), and a polarity of a current, the gain being calculated from a DC voltage value supplied to the electric power converter, a dead time, and a switching frequency.

Electric power converter and motor driving system

A synchronous motor controlling apparatus which can be applied to the carrier synchronized position estimating method as well and have protection-related functions such as detection of inverted magnetic pole position of a motor in a simple method, and an electric motor using the synchronous motor control apparatus. A controller controls a voltage applied to an AC motor with a PWM signal. A magnetic pole position detector of the controller detects a current of the AC motor to estimate a pole position of the AC motor. A fault detector detects a fault in the estimated magnetic position of the AC motor.

Motor control apparatus and electric vehicle using same

A provide a position-sensorless motor control apparatus comprises a salient-pole AC motor , a PWM inverter for applying voltage to the AC motor , and a controller for controlling the PWM inverter by means of PWM signals, wherein the controller has a position estimation means which detects motor inductance in the pre-determined direction to the vector direction of the current that flows through the AC motor and estimates the AC motor's rotor position based on the motor inductance.

Position-sensorless motor control method and apparatus

An apparatus for executing field weakening control comprises a means for computing a start rotational speed of field weakening control based on a ratio of a battery voltage used in a normal operation to a detected battery voltage in execution of only field weakening control without generating a torque, and an interpolation means for carrying out linear interpolation on at least two values selectively fetched from a plurality of current tables in accordance with a battery voltage to find a field weakening current. The apparatus provided by the present invention is further characterized in that, in addition to correction of a start rotational speed of the field weakening control, a field weakening current is corrected in accordance with a ratio of a rated battery voltage used in a normal operation to a detected battery voltage.

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Ishioka, Japan

Takefumi Sawada