Kabushiki Kaisha Yaskawa Denki

Tomohiro Kawachi

Kenji Tomohara

Koji Higashikawa

Masashi Takenouchi

Zhenning Chen

Hideaki Iura

Yoichi Yamamoto

Mitsunori Kuzushima

A winding switching signal generator is configured to obtain information indicating a degree of field weakening from at least one of a current command calculator and a constant output controller, and to generate a winding switching signal for switching from a low speed rotation state to a high speed rotation state when the degree of the field weakening exceeds a predetermined condition in the low speed rotation state.

Motor control apparatus and motor control method

An inverter device according to an embodiment includes a constant power controller. The constant power controller computes and outputs, when a value of a voltage reference to an AC motor exceeds a predetermined threshold value, a d-axis current reference correction value on the basis of the value of the voltage reference and the predetermined threshold value. Moreover, the constant power controller generates the d-axis current reference correction value by using a constant power model determined by a torque reference or a speed reference and a supplied direct voltage at an output switching timing determined based on a winding switching signal and outputs the d-axis current reference correction value for a predetermined time.

Inverter device and electric motor drive system

Provided is an inverter apparatusconfigured to switch a current winding to an optimal winding when a rotation speed of a rotor of an AC electric motoris within a hysteresis region defined by first and second switch timings for switching a state of an armature winding between a first winding and a second winding and when the current winding differs from the optimal winding.

Inverter apparatus, method of controlling inverter apparatus, and electric motor drive system

A technique for controlling an AC motor. An electric power is output to the AC motor. The output current of an electric power converter is controlled based on a difference signal of an output current detection signal and a current command signal of the electric power converter. When the AC motor is in a free run condition, current control is conducted by forcing the current command signal to be zero so that a current in the AC motor is made zero. The amplitude and phase and angular velocity of a residual voltage of the AC motor are found based on a calculated output voltage command.

Growing community of inventors

Kitakyushu, Japan

Tomohiro Kawachi