US 5,847,534 AGranted

Control system for electric vehicle

AssigneeHitachi, Ltd.

InventorsTokunosuke Tanamachi, Kiyoshi Nakamura

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Abstract

The control system is constructed so that an inverter output frequency command is increased/decreased based on a frequency-to-time rate-of-change command, and the frequency-to-time rate-of-change command is controlled with a current control system. Further, it is also constructed so that the frequency-to-time rate-of-change command is adjusted and the current command is changed with a readhesion control system. The control system is capable of accelerating and decelerating the vehicle with a torque corresponding to an inverter output current command which is generated basically without using any rotational frequency of induction motor, and further capable of accelerating and decelerating the vehicle with a torque corresponding to a value near the limit adhesion between the wheel and the rail under a condition of occurrence of slip/skid.

Claims13

Dependent claims

A control system for an electric vehicle comprising:

at least one induction motor for driving an electric vehicle;
an inverter for driving said induction motor;
means for generating a current command for controlling a current output from said inverter;
means for detecting an output current of said inverter;
means for generating a reference frequency-to-time rate-of-change command corresponding to an acceleration/deceleration of said vehicle and being larger than a time-to-change rate of an output frequency of said inverter;
means for detecting a quantity of slip/skid of a driving wheel driven by said induction motor;
means for generating a frequency-to-time rate-of-change command by adjusting said reference frequency-to-time rate-of-change command corresponding to a difference between said detected value of said output current and said current command and said detected value of said quantity of slip/skid when said detected value of said output current is larger than said current command;
means for generating an output frequency command for controlling said inverter based on said frequency-to-time rate-of-change command;
and
readhesion means for changing said current command based on said detected value of said output current when a time period of a state where said detected value of said output current is smaller than said current command exceeds a given time period.

7 more elements

A control system for an electric vehicle comprising:

at least one induction motor for driving an electric vehicle;
an inverter for driving said induction motor;
means for generating a current command for controlling a current output from said inverter;
means for detecting an output current of said inverter;
means for generating a reference frequency-to-time rate-of-change command corresponding to an acceleration/deceleration of said vehicle and being larger than a time-to-change rate of an output frequency of said inverter;
means for detecting a quantity of slip/skid of a driving wheel driven by said induction motor;
means for generating a first frequency-to-time rate of-change command limited so as to not exceed said reference frequency-to-time rate-of-change command based on a difference between said current command and said detected value of said output current;
means for generating a second frequency-to-time rate-of-change command by adjusting said first frequency-to-time rate-of-change command corresponding to said detected value of said quantity of slip/skid;
means for generating an output frequency command for controlling said inverter based on said second frequency-to-time rate-of-change command;
and
readhesion means for changing said current command based on the detected value of said output current when the time period of a state where said detected value of said output current is smaller than said current command exceeds a given time period.

8 more elements

Dependencies are inferred from the claim text.