Motor control device for electric vehicle

An electric vehicle motor control device for an electric vehicle in which power from an electric motor is transmitted after an accelerator operation to driving wheels via an automatic transmission, the electric vehicle motor control device comprising:

• a vehicle speed detecting device that detects a vehicle speed of the electric vehicle;
• a controller including
• a required driving power calculating section that calculates a required driving power of the electric vehicle;
• and
• a target motor rotational speed calculating section that calculates a target motor rotational speed of the electric motor so that an efficiency of a product of a power consumption rate of the electric motor and a transmission efficiency of the automatic transmission will become a prescribed target efficiency, based on the vehicle speed and the required driving power, and
• a target gear ratio calculating section that calculates a target gear ratio of the automatic transmission from the target motor rotational speed and the vehicle speed,
• a shift control section that achieves the target motor rotational speed by shift control of the automatic transmission so that an actual gear ratio of the automatic transmission moves toward the target gear ratio that is calculated by the target gear ratio calculating section,
• a target motor torque calculating section that calculates a target motor torque of the electric motor to achieve the required driving power for the target motor rotational speed by dividing the required driving power by the target motor rotational speed, and
• a motor drive force controlling section that achieves the target motor torque by drive force controlling the electric motor so that an actual motor torque of the electric motor will move towards the target motor torque that is calculated by the target motor torque calculating section,
• the controller being programmed to control the electric motor based on the target motor rotational speed that is determined by the target motor rotational speed calculating section.