Control method and device for series-parallel connection mode switching of dual-motor power system

Abstract

The invention relates to a control method and device for series-parallel connection mode switching of a dual-motor power system. The method comprises the following steps: when a request for switchingthe dual motors from a series connection mode to a parallel connection mode is received, oil charging of a clutch is performed and the rotating speed of an engine is adjusted to reach preset conditions, and the dual motors comprise a first motor and a second motor; when oil charging of the clutch is performed and the rotating speed of the engine is adjusted to reach the preset conditions, whetherthe current working state of the clutch meets a locking state or not is judged; and if the current working state meets the locking state, the clutch starts locking, torque compensation is conducted onthe first motor or the second motor at the same time until the clutch completes locking, and after the clutch completes locking, the system is driven to be switched to the parallel connection mode from the series connection mode through torque exchange between the first motor and the second motor. Torque compensation of the two motors is adopted, the inertia torque difference value generated by inconsistent angular accelerations at the two ends of the clutch can be offset, clutch locking impact is reduced, smooth transition of series-parallel connection mode switching is achieved, and the drivability is improved.

Description

technical field [0001] The invention relates to the field of hybrid power technology, in particular to a control method and device for switching between series and parallel modes of a dual-motor power system. Background technique [0002] With the development of the economy and the reduction of traditional energy sources, more and more car manufacturers are developing hybrid vehicles to replace traditional energy vehicles, which can solve the traditional energy reduction and meet the daily travel needs of people. [0003] At present, the mainstream products of hybrid systems on the market are single-motor hybrid architectures. However, when the engine intervenes at low and medium speeds in a single-motor hybrid system, the efficiency of the vehicle will be reduced because the engine cannot work in the high-efficiency range. Many Automakers have developed a dual-motor hybrid system, which can solve the problem that the engine cannot work in the high-efficiency range at low an...

AI Technical Summary

Problems solved by technology

[0003] At present, the mainstream products of hybrid systems on the market are single-motor hybrid architectures. However, when the engine intervenes at low and medium speeds in a single-motor hybrid system, the efficiency of the vehicle will be reduced because the engine cannot work in the high-efficiency range. Many Automakers have developed a hybrid system with a dual-motor architecture, which can solve the problem that the engine cannot work in the high-efficiency range at low and medium speeds, and improve vehicle efficiency

[0004] However, in an architecture similar to the dual-motor architecture, the switch between the serial mode (Serial Mode) and the parallel mode (Parallel Mode) is switched by controlling the opening and closing of a clutch. In the serial mode, the low-speed battery SOC is insufficient or When the output power of the battery does not meet the demand, the engine starts, and the engine speed is adjusted to an optimal working condition to use the P1 motor to generate power. The power generation is mainly used to drive the P2 motor. In the working condition, the engine speed can be adjusted freely because the clutch is open; in parallel mode, when the vehicle is running at high speed, the engine power is directly output through the gearbox through the clutch engagement, and the engine speed is very high at this time, which can easily reach the optimum Efficiency working range; when switching from the series mode to the parallel mode, the clutch needs to be combined. Generally, the speed difference between the two ends of the clutch reaches a certain value through speed regulation (motor speed regulation or clutch friction speed regulation) and then the clutch is locked. Realize switching between series and parallel connection, however, in the prior art, at the end of the speed regulation, if there is a difference in the angular acceleration of the shafts at both ends of the clutch, the lock-up clutch will generate inertial impact, which will affect the drivability

[0005] Therefore, in the prior art, due to the difference in the angular acceleration of the shafts at both ends of the clutch, the inertial impact of the clutch is an urgent problem for those skilled in the art.

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