US 4,757,240 A · Apparatus for controlling electric vehicle using induction motor

Abstract

A main circuit of an electric vehicle using an induction motor is constituted by an invertor for producing three phase AC power having a variable frequency and a variable voltage and a three-phase induction motor supplied with the AC power by the invertor. The rotational speed of the induction motor is detected and a slip frequency signal is added (in power running) or subtracted (in regenerating running) to or from the rotational speed to control the output frequency of the invertor. On the other hand, the output voltage of the invertor is controlled to be in proportion to the output frequency thereof. The output voltage of the invertor is limited in accordance with notch positions of a master controller of the electric vehicle so as to be provided with a voltage notch stopping characteristic of the conventional electric vehicle. A constant speed notch for producing a constant speed running command is additionally provided in the master controller, and in response to the constant speed running command, the speed command for constant speed running is selected to be a value equal to or a value higher by a predetermined value than an actual speed of the electric vehicle at that time. When the speed of the electric vehicle approaches the speed command for constant speed running, the slip frequency is reduced to realize the constant speed running.

Claims25

Dependent claims

An apparatus for controlling an electric vehicle provided with an electric power converter for producing an output having a variable voltage and a variable frequency, an induction motor supplied with said output of said electric power converter, speed detecting means for producing an actual speed signal corresponding to an actual speed of said vehicle, frequency control means for adding/reducing a first slip frequency command to/from said actual speed signal to thereby control a frequency of said output of said power converter, voltage control means for controlling a voltage of said output of said power converter so as to make said voltage be in proportion to a frequency control command from said frequency control means, or for controlling said voltage in accordance with a deviation of an actual motor current signal from a motor current command;

said apparatus further comprising:
means for limiting a voltage command of said voltage control means correspondingly to notch positions of a master controller;
operation means for generating a constant speed running command;
means for generating a speed command signal corresponding to said constant speed running command;
comparator means for comparing said actual speed signal with said speed command;
means for generating a second slip frequency command which changes positively or negatively in accordance with an output of said comparator means;
and
means for substituting said second slip frequency command for said first slip frequency command when said constant speed running command is generated.

5 more elements

An apparatus for controlling an electric vehicle comprising:

an electric power converter producing an output having a variable voltage and a variable frequency;
an induction motor supplied with said output of said electric power converter;
speed detecting means for detecting an actual speed of said vehicle and outputting a speed signal corresponding to said actual speed;
frequency control means for controlling a frequency of said output of said power converter by either adding a slip frequency signal to said speed signal or subtracting the slip frequency signal from said speed signal;
voltage control means for controlling a voltage of said output of said power converter;
a master controller including a first operation means having a plurality of notch positions for selecting one of said notch positions;
means for adjusting outputs of said slip frequency signal and/or voltage control means according to one of the notch positions selected by said first operation means by acting on one of said frequency control means and said voltage control means;
second operation means for commanding constant speed running of said induction motor;
means for producing a speed command signal corresponding to the command for constant speed running from said second operation means;
and
means associated with said frequency control means to produce an output related to said speed command signal in response to said command of constant speed running.

8 more elements

An apparatus for controlling an electric vehicle comprising:

an electric power converter producing an output having a variable voltage and a variable frequency;
an induction motor supplied with said output of said electric power converter;
speed detecting means for detecting an actual speed of said vehicle and outputting a speed signal corresponding to said actual speed;
frequency control means for controlling a frequency of said output of said power converter by either adding a slip frequency signal to said speed signal or subtracting the slip frequency signal from said speed signal;
voltage control means for controlling a voltage of said output of said power converter;
a master controller including a first operation means having a plurality of notch positions for selecting one of said notch positions;
means for limiting an output of said voltage control means according to one of the notch positions selected by said first operation means;
second operation means for commanding constant speed running of said induction motor;
means for producing a speed command signal corresponding to the command for constant speed running from said second operation means;
and
means associated with said frequency control means to produce an output related to said speed command signal in response to said command of constant speed running.

8 more elements

An apparatus for controlling an electric vehicle comprising:

an electric power converter producing an output having a variable voltage and a variable frequency;
an induction motor supplied with said output of said electric power converter;
speed detecting means for detecting an actual speed of said vehicle and outputting a speed signal corresponding to said actual speed;
frequency control means for controlling a frequency of said output of said power converter by either adding a first slip frequency signal to said speed signal or subtracting the slip frequency signal from said speed signal;
voltage control means for controlling a voltage of said output of said power converter in proportional to the output of said frequency control means;
a master controller including operation means having a plurality of notch positions of power running and constant speed runnning for selecting one of said notch positions;
means for limiting output of said voltage control means according to one of the notch positions of the power running selected by said operation means;
means, in response to the selecting of a notch position of constant speed running at said master controller, for producing a speed command signal corresponding to the speed signal at a time when said notch is selected;
means for comparing said speed command signal and said speed signal;
means for generating a second slip frequency signal which is varied according to the output of said comparing means;
and
means for replacing said first slip frequency signal with said second slip frequency signal when said notch position of constant speed running is selected.

9 more elements

Dependencies are inferred from the claim text.

Apparatus for controlling electric vehicle using induction motor

Life of this patent

Apparatus for controlling electric vehicle using induction motor

Life of this patent

Abstract

Claims25