Anti-slip strategy for pure electric buses driven by permanent magnet motors on ramps

Abstract

The invention discloses an anti-slip strategy for hill starting of a pure electric bus driven by a permanent magnet motor. According to the strategy, when a brake pedal is stepped down and the rotating speed of the permanent magnet motor is smaller than a set value for a certain time period, a vehicle control unit generates a brake triggering signal; when the opening degree of an accelerator pedal is smaller than a set value and the gear position is located on a non-neutral position, a motor control unit generates an anti-slip function enabled signal and automatically carries out anti-slip control so that the permanent magnet motor can enter a rotating speed closed loop to be controlled at a certain target rotating speed; if the vehicle control unit detects that the brake pedal is still stepped down, the vehicle control unit limits the permanent magnet motor to output torque, or else restores the permanent magnet motor to output the torque; when detecting that the opening degree of the accelerator pedal is larger than the set value and the gear position is located on the non-neutral position or a hand brake is located on a parking position, the vehicle control unit exits from the anti-slip control and is switched to the torque control at the same time. According to the strategy, the anti-slipping of vehicles can be achieved without changing an existing vehicle structure or adding hardware such as an auxiliary sensor.

Description

technical field [0001] The invention relates to an anti-slip strategy for a pure electric bus driven by a permanent magnet motor when starting on a slope. Background technique [0002] Usually, a pure electric bus driven by a permanent magnet motor has a power system composed of a power battery and a permanent magnet motor without an engine assembly, so it is different from traditional fuel vehicles and hybrid vehicles. Since the permanent magnet motor has the characteristics of stepless speed change, its motor shaft is directly connected with the main reducer of the rear axle of the vehicle through the transmission shaft, and the reduction box and clutch are omitted in the power transmission, so the structure of the whole vehicle is different from that with a reducer. Pure electric vehicles. [0003] Like pure electric vehicles, all the power of pure electric direct drive buses comes from power batteries. In terms of power control, it includes power modules, motor control ...

AI Technical Summary

Problems solved by technology

Similarly, when the motor is used to lock the car at zero speed, the motor is in a locked-rotor state, which will cause the three-phase current imbalance of the motor, resulting in the risk of heat damage to the one-phase power module with a large current, and cannot be used for a long time

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