Hitachi, Ltd.

Toshihiko Sekizawa

Kinji Mori

Katsumi Kawano

Atsushi Oda

Masayuki Orimo

Yasuo Suzuki

Hirokazu Kasashima

Kozo Nakai

Minoru Koizumi

Kiyoshi Nakata

Tetsuo Kojima

Eiichi Toyota

Motomi Shimada

Makoto Yasuda

Keiichi Katsuta

Yuhi Tsutsumi

Hiroyuki Matsumura

Minoru Koizumo

Takayoshi Nishino

Masataka Yokota

To determine the timing of the electrical brake for completely stopping in electrical braking control, and also to achieve both sure stopping and good riding comfort in an electric vehicle powered by the motor by decreasing the braking force at a prescribed rate of change, the torque of the electric motor is controlled by controlling the power converter which powers the motor using a power converter controller. The deceleration of the motor is computed based on the detected speed of the electric motor which is as an output of the speed detection means, the subsequent speed of the electric motor is estimated based on the detected speed and the deceleration rate of the electric motor at the time the detected rotational speed of the electric motor falls below a prescribed speed, and torque control is carried out using an electric power converter controller, based on the estimated speed.

Control apparatus of electric vehicle

In a distributed processing system wherein a plurality of processors are connected through a network and wherein programs are transmitted among the processors; each of the processors monitors the status of a program in the processor or the load status of any other of the processors as indicated by a message on the network. Upon performance of a judgement operator, the processor broadcasts a message indicative of the status of the processor or a program with a content indicating code affixed thereto, to another network, and the processor having received the message broadcasts a program existent in the other processor to the network along with the code indicative of the content of the program. The broadcast is performed in the other processor in accordance with the load statuses of the processors, and upon judging the content of the received message. Each processor judges whether or not the program being broadcast corresponds to a function necessary for a process of the processor based on the code indicative of the content of the program. If the program is needed, the processor loads and executes the program.

Program loading method and system for distributed processing system

Programs in a plurality of processors connected through a common network are started when a plurality of data necessary for starting the program are received from the network. When the processor receives data from an external equipment, it adds the event number to the data and sends it to the network, and each processor determines whether all data necessary for starting the program in itself have been received and checks the relation among the received data by comparison with the event numbers of the received data.

Method for processing data in a distributed processing system

A PWM (pulse width modulation) inverter generating an a.c. output having a variable voltage and a variable frequency supplies a.c. power to a linear induction motor. An electric car supported by wheels is driven by a driving torque produced by the linear induction motor. While the electric car is running, the motor torque varies due to various factors among which a variation of the air gap length is representative. The power factor cos .phi. of the PWM inverter is detected to calculate the motor torque, and the output voltage of the PWM inverter is regulated or mechanical brakes are controlled so as to compensate the torque variation. Thus, the variation of the air gap length, which is representative of the factors giving rise to torque variations and which has been difficult to be detected, can be reliably detected to permit torque control according to the torque variation of the linear induction motor.

Apparatus and method for controlling electric car

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Katsuta, Japan

Toshihiko Sekizawa