Electric drive system based on two-gear speed changing and coordinated gear shifting control method of electric drive system

Abstract

The invention provides an electric drive system based on two-gear speed changing and a coordinated gear shifting control method of the electric drive system. The electric drive system comprises a power supplying unit, a motor controller, a motor, a vehicle controller, a gear shifting controller and a two-gear planet speed changer. The two-gear planet speed changer is internally provided with a planet transmission two-gear automatic speed changing box and a wet clutch to shift gears, gear shifting is convenient, and the size and the weight are greatly reduced. In the gear shifting process, the vehicle controller controls the motor controller and the gear shifting controller through a bus in a communication mode, the motor controller controls the motor output torque to track the optimal motor torque track, the gear shifting controller controls gear shifting oil pressure to track the optimal gear shifting oil pressure track, and therefore synchronous adjusting of the motor torque and the gear shifting oil pressure is achieved, the difference of the rotating speed of a main component and the rotating speed of an auxiliary component and the gear shifting impact when a clutch and a brake are combined or separated are reduced, and smooth gear shifting is achieved.

Description

technical field [0001] The invention relates to an electric drive system and a shift control method, in particular to an electric drive system based on two-speed shifting and a coordinated shift control method thereof. Background technique [0002] At present, the electric drive system of pure electric drive vehicles generally adopts the method of adding a gearbox between the motor and the driving wheel to adjust the output torque and speed of the motor to meet the traction demand of the vehicle. For pure electric vehicles, the fixed-shaft automatic transmission represented by AMT (automatic mechanical transmission) is widely used, but there is power interruption during the shifting process, the shifting impact is large and repeated calibration is required, and the transmission The dynamic load of the system affects the life of the transmission system; while the AT (hydraulic automatic transmission) has a complex structure, low transmission efficiency, and large power loss; ...

AI Technical Summary

Problems solved by technology

For pure electric vehicles, the fixed-shaft automatic transmission represented by AMT (automatic mechanical transmission) is widely used, but there is power interruption during the shifting process, the shifting impact is large and repeated calibration is required, and the transmission The dynamic load of the system affects the life of the transmission system; while the AT (hydraulic automatic transmission) has a complex structure, low transmission efficiency, and large power loss; the transmission belt of the CVT (mechanical continuously variable automatic transmission) is easily damaged and cannot bear large loads; DSG (Direct Shift Transmission) has complex structure and high manufacturing cost

If a fixed speed ratio reducer is used, there is no need to shift gears, but a drive motor with a larger torque needs to be selected, which has problems such as a large surplus of motor power, large volume and weight of the motor and the drive system, and high cost.

[0003] The fixed-shaft AMT gearboxes that have been disclosed generally have three gears, and the corresponding gear shifting control mechanism mostly uses a synchronizer. Clutch shifting, but this makes the gearbox structure and shifting control complex, and the volume and weight advantages are not obvious

[0004] In the selection of shift control methods, most of the current research only considers the efficiency of the motor itself, while ignoring the difference in efficiency of the gearbox at different speeds, which will lead to non-optimal results and make the shift process unstable.

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