Hitachi, Ltd.

Hiatchi, Ltd.

Takeshi Ando

Akira Horie

Eiichi Toyota

Yoshio Tsutsui

Takayuki Matsui

Syuuji Saitoo

Masato Suzuki

Kiyoshi Nakata

Tokunosuke Tanamachi

Takashi Kaneko

Kouji Yasuda

Ken Itou

A controller for electric vehicles comprising a vector control inverter for controlling motors, which drive wheels of the electric vehicles, by dividing the primary current of the motors into an exciting current component and a torque current component, and controlling respective of the current components based on a respectively designated command, characterized in further comprising a dectector for detecting a wheel velocity (including a rotor frequency of the motor proportional to the wheel velocity), a detector for detecting slipping and skidding of the wheel based on a differential value (a changing rate with time) of the detected wheel velocity, a dectector for detecting re-adhesion of the wheel based on the differential value and a twice differential value of the detected wheel velocity, and an adjuster for adjusting the designated command for the torque current component in response to the detectors.

Controller for electric vehicles

Apparatus and method for controlling induction motor

A power converter including a snubber circuit which is smaller and regenerates more energy than a conventional snubber circuit. A plurality of self-quenching semiconductor switching elements are connected in series across a power supply. A capacitive element is connected to the switching elements, and is charged to more than the voltage of the power supply by a snubber action due to operation of any of the switching elements. The charge stored in the capacitive element is then regenerated to the power supply. The capacitance of the capacitive element can be almost as small as a minimum required capacitance, and can be as small as one-tenth of the capacitance required in a conventional snubber circuit, thereby providing a power converter which is smaller and has a smaller snubber loss than a conventional power converter.

Power converter

In a multi-series inverter arrangement comprising a DC circuit including a neutral point output terminal and a multi-series inverter including three series connections of first through fourth GTOs, each connected in parallel with the DC circuit, the juncture of the first and second GTOs and the juncture of the third and fourth GTOs being connected to the neutral point output terminal via respective clamping diodes and the first and third GTOs and the second and fourth GTOs being on and off controlled each other in a conjugate relationship, individual gate driving circuits for the second and third GTOs being designed to provide a larger gate current, in particular, a larger wide width gate forward current to the corresponding GTOs than that provided by individual gate driving circuits for the first and fourth GTOs to the corresponding GTOs.

Multi-series inverter arrangement

Growing community of inventors

Katsuta, Japan

Takeshi Ando