Controlling apparatus and method for electric drive transmission of dual-motor electric vehicle

A controlling apparatus for an electric drive transmission used in a dual-motor electric vehicle, wherein dual motors of the electric vehicle comprise first and second motors, the electric drive transmission is coupled with the first and second motors in a way that the first motor outputs power with a single gear, and the second motor selectively outputs power with two gears by means of a single synchronizer, and the controlling apparatus is configured to receive information sent from a vehicle controller, to control operations of the first and second motors and the electric drive transmission, and to perform a gear-shifting procedure of the synchronizer by the steps of:

• (1) the controlling apparatus starts to intervene in torque distribution of the vehicle controller;
• (2) when the second motor is in a zero torque state, the synchronizer is shifted to a neutral position, and in this stage, the required torque of the second motor remains at zero;
• (3) after the synchronizer is shifted to the neutral position, if a target gear position that the synchronizer is to be moved to is the neutral position, the gear-shifting procedure is completed, and if the target gear position is not the neutral position, speed control to the second motor is conducted to adjust its speed towards a target speed;
• (4) once the speed of the second motor has been adjusted to the target speed, the second motor is subjected to zero torque control, the required torque of the second motor being zero;
• (5) once the second motor comes into a zero torque state, the synchronizer starts to be shifted to the target gear position, and in this stage, the required torque of the second motor remains at zero;
• (6) once the synchronizer is located in the target gear position, the required torque of the second motor changes towards a target value at a changing rate;
• and
• (7) when the second motor and has a real torque that is equal to or larger than a target torque, the gear-shifting procedure is judged as completed.