Hitachi, Ltd.

Unisia Jecs Corporation

Tatsuo Matsumura

Mitsuo Sasaki

Toru Takahashi

Yoshitaka Iwaji

Kazuaki Tobari

Ayumu Miyajima

Isamu Tsubono

Takaomi Nishigaito

Toshimitsu Sakaki

Kentaro Oi

A motor control apparatus which controls an output voltage reference for an inverter driving a permanent magnet synchronous motor based on d-axis and q-axis current references, d-axis and q-axis current detected values, and a computed frequency value. When a torque reference specifying torque greater than maximum torque that the motor can output is input, a limit value for a phase angle that is a deviation between a rotation phase reference of control and a rotation phase value of the motor is varied depending on a quantity of the predetermined state.

Field weakening control apparatus for permanent magnet motor and electric power steering using same

In a power steering system comprising a power cylinder for assisting a steering power of a steering mechanism, a hydraulic pump for supplying a hydraulic pressure to the power cylinder, a first oil passage and a second oil passage connecting the power cylinder and the hydraulic pump respectively, a motor for driving the hydraulic pump, and power steering control means for calculating a command value to the motor based on the steering torque, a flow rate of the working oil supplied from a high-pressure side oil passage to a low-pressure side oil passage is restrained at the transition from the end of the steering state (lock end) of the steering mechanism to the returning. The flow-rate restraint increasingly corrects a driving current of the motor in the steering direction or limits the flow rate of the working oil.

Power steering system

In an apparatus for variably controlling valve timing of engine by generating, between a crankshaft and a cam shaft, a phase difference which periodically varies in a manner synchronized with a rotational phase of the cam shaft: actual phase differences are obtained at two discrete rotational phases of the cam shaft, respectively; there is assumingly calculated an amount of deviation (phase deviation .theta.) of phase difference relative to the rotational phase of the cam shaft; and the phase difference is feedback controlled based on that value of the detected phase difference which is corrected in accordance with the amount of deviation (phase deviation .theta.).

Apparatus and method for controlling valve timing of engine

Growing community of inventors

Atsugi, Japan

Tatsuo Matsumura