Control apparatus and control method for motor drive vehicle

A method for controlling a vehicle driven by an electric motor, comprising the steps of:

• setting a target vehicle speed according to operation amount of an accelerator device;
• detecting actual speed of said vehicle;
• calculating difference between said target vehicle speed and the actual vehicle speed;
• and
• controlling a vehicle speed to make the difference zero, said vehicle speed controlling step further including the steps of:
• generating a target motor speed according to a predetermined high efficiency pattern whereon maximum efficiency points are plotted in relation to the motor speed values and motor power values obtained from values of said the difference;
• driving said electric motor in said target motor speed;
• determining a translation ratio on the basis of said target vehicle speed and said target motor speed;
• and
• varying rotation speed of said output of the motor in said transmission ratio so as to transfer the rotation to a drive shaft of said vehicle.

A control apparatus of a vehicle driven by an electric motor, comprising:

• a target vehicle speed generating unit providing a target vehicle speed according to an operator input of an accelerator device;
• vehicle speed control unit, having an actual speed detection unit and a difference calculating unit for calculating a difference between said target vehicle speed and the actual vehicle speed, for controlling a vehicle speed so as to make the difference zero;
• motor speed instruction device for receiving an instruction value corresponding to a value of said different and for generating a target motor speed according to a predetermined high efficiency pattern whereon maximum efficiency points are plotted in relation to the motor speed values and motor power values obtained from values of said difference;
• motor control unit for receiving said target motor speed from said motor speed instruction device and driving said electric motor in said target motor speed;
• a variable transmission for receiving output of said electric motor and varying rotation speed of said output of the motor in a transmission ratio instructed so as to transfer the rotation to a drive shaft of said vehicle;
• and
• transmission ratio calculating unit for determining said transmission ratio on the basis of said target vehicle speed and said target motor speed and instructing said transmission ratio to said variable transmission.